2023

Jump to: 2022, 2021

14 pages, 6488 KiB

Open AccessArticle

Biodegradation Studies of Polyhydroxybutyrate and Polyhydroxybutyrate-co-Polyhydroxyvalerate Films in Soil

by Jihyeon Kim, Nevin S. Gupta, Lindsey B. Bezek, Jacqueline Linn, Karteek K. Bejagam, Shounak Banerjee, Joseph H. Dumont, Sang Yong Nam, Hyun Woo Kang, Chi Hoon Park, Ghanshyam Pilania, Carl N. Iverson, Babetta L. Marrone and Kwan-Soo Lee

Int. J. Mol. Sci. 2023, 24(8), 7638; https://doi.org/10.3390/ijms24087638 - 21 Apr 2023

Cited by 5 | Viewed by 2764

Abstract

Due to increased environmental pressures, significant research has focused on finding suitable biodegradable plastics to replace ubiquitous petrochemical-derived polymers. Polyhydroxyalkanoates (PHAs) are a class of polymers that can be synthesized by microorganisms and are biodegradable, making them suitable candidates. The present study looks [...] Read more.

Due to increased environmental pressures, significant research has focused on finding suitable biodegradable plastics to replace ubiquitous petrochemical-derived polymers. Polyhydroxyalkanoates (PHAs) are a class of polymers that can be synthesized by microorganisms and are biodegradable, making them suitable candidates. The present study looks at the degradation properties of two PHA polymers: polyhydroxybutyrate (PHB) and polyhydroxybutyrate-co-polyhydroxyvalerate (PHBV; 8 wt.% valerate), in two different soil conditions: soil fully saturated with water (100% relative humidity, RH) and soil with 40% RH. The degradation was evaluated by observing the changes in appearance, chemical signatures, mechanical properties, and molecular weight of samples. Both PHB and PHBV were degraded completely after two weeks in 100% RH soil conditions and showed significant reductions in mechanical properties after just three days. The samples in 40% RH soil, however, showed minimal changes in mechanical properties, melting temperatures/crystallinity, and molecular weight over six weeks. By observing the degradation behavior for different soil conditions, these results can pave the way for identifying situations where the current use of plastics can be replaced with biodegradable alternatives. Full article

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25 pages, 2729 KiB

Open AccessReview

Overview of Antimicrobial Biodegradable Polyester-Based Formulations

by Oana Gherasim, Valentina Grumezescu and Stefan Andrei Irimiciuc

Int. J. Mol. Sci. 2023, 24(3), 2945; https://doi.org/10.3390/ijms24032945 - 02 Feb 2023

Cited by 1 | Viewed by 2510

Abstract

As the clinical complications induced by microbial infections are known to have life-threatening side effects, conventional anti-infective therapy is necessary, but not sufficient to overcome these issues. Some of their limitations are connected to drug-related inefficiency or resistance and pathogen-related adaptive modifications. Therefore, [...] Read more.

As the clinical complications induced by microbial infections are known to have life-threatening side effects, conventional anti-infective therapy is necessary, but not sufficient to overcome these issues. Some of their limitations are connected to drug-related inefficiency or resistance and pathogen-related adaptive modifications. Therefore, there is an urgent need for advanced antimicrobials and antimicrobial devices. A challenging, yet successful route has been the development of new biostatic or biocide agents and biomaterials by considering the indisputable advantages of biopolymers. Polymers are attractive materials due to their physical and chemical properties, such as compositional and structural versatility, tunable reactivity, solubility and degradability, and mechanical and chemical tunability, together with their intrinsic biocompatibility and bioactivity, thus enabling the fabrication of effective pharmacologically active antimicrobial formulations. Besides representing protective or potentiating carriers for conventional drugs, biopolymers possess an impressive ability for conjugation or functionalization. These aspects are key for avoiding malicious side effects or providing targeted and triggered drug delivery (specific and selective cellular targeting), and generally to define their pharmacological efficacy. Moreover, biopolymers can be processed in different forms (particles, fibers, films, membranes, or scaffolds), which prove excellent candidates for modern anti-infective applications. This review contains an overview of antimicrobial polyester-based formulations, centered around the effect of the dimensionality over the properties of the material and the effect of the production route or post-processing actions. Full article

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17 pages, 2850 KiB

Open AccessArticle

The Influence of Constraints on Gelation in a Controlling/Living Copolymerization Process

by Piotr Polanowski and Andrzej Sikorski

Int. J. Mol. Sci. 2023, 24(3), 2701; https://doi.org/10.3390/ijms24032701 - 31 Jan 2023

Viewed by 1099

Abstract

We developed a simple model of the copolymerization process in the formation of crosslinked macromolecular systems. A living copolymerization was carried out for free chains, in bulk and in a slit, as well as for grafted chains in a slit. In addition, polymer [...] Read more.

We developed a simple model of the copolymerization process in the formation of crosslinked macromolecular systems. A living copolymerization was carried out for free chains, in bulk and in a slit, as well as for grafted chains in a slit. In addition, polymer 2D brushes were placed in a slit with initiator molecules attached to one of the confining walls. Coarse-grained chains were embedded in the vertices of a face-centered cubic lattice with the excluded volume interactions. The simulations of the copolymerization processes were performed using the Dynamic Lattice Liquid algorithm, a version of the Monte Carlo method. The influence of the initial initiator to cross-linker ratio, slit width and grafting on the polymerization and on the gelation was examined. It was also shown that the influence of a confining slit was rather small, while the grafting of chains affected the location of the gel pint significantly. Full article

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2022

Jump to: 2023, 2021

13 pages, 2782 KiB

Open AccessArticle

Electrical Detection of Vibrations of Electrospun PVDF Membranes

by Petr Slobodian, Robert Olejnik, Jiri Matyas, Berenika Hausnerova, Pavel Riha, Romana Danova and Dusan Kimmer

Int. J. Mol. Sci. 2022, 23(22), 14322; https://doi.org/10.3390/ijms232214322 - 18 Nov 2022

Cited by 3 | Viewed by 1359

Abstract

We prepared electroactive PVDF membranes, which were subjected to mechanical as well as dual electro–mechanical signals and their responses were detected by the evoked electrical pulses. The aim was to obtain primarily electric energy that could be used for light signalling, sensing of [...] Read more.

We prepared electroactive PVDF membranes, which were subjected to mechanical as well as dual electro–mechanical signals and their responses were detected by the evoked electrical pulses. The aim was to obtain primarily electric energy that could be used for light signalling, sensing of the membrane properties and membrane motion detection. The obtained data showed the unique as well as usable properties of PVDF membranes. From this point of view, the gain and analysis of the electrical responses to combined electro–mechanical loads of PVDF membranes have been important in terms of identifying the mechanism. The detected electrical response of the PVDF membrane to their electro–mechanical pulses also indicated the possibility of using this phenomenon. Among others, it suggests monitoring of membrane fouling and use for a self-cleaning mechanism. Full article

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23 pages, 8493 KiB

Open AccessArticle

Highly Organized Porous Gelatin-Based Scaffold by Microfluidic 3D-Foaming Technology and Dynamic Culture for Cartilage Tissue Engineering

by Hsia-Wei Liu, Wen-Ta Su, Ching-Yi Liu and Ching-Cheng Huang

Int. J. Mol. Sci. 2022, 23(15), 8449; https://doi.org/10.3390/ijms23158449 - 30 Jul 2022

Cited by 9 | Viewed by 2345

Abstract

A gelatin-based hydrogel scaffold with highly uniform pore size and biocompatibility was fabricated for cartilage tissue engineering using microfluidic 3D-foaming technology. Mainly, bubbles with different diameters, such as 100 μm and 160 μm, were produced by introducing an optimized nitrogen gas and gelatin [...] Read more.

A gelatin-based hydrogel scaffold with highly uniform pore size and biocompatibility was fabricated for cartilage tissue engineering using microfluidic 3D-foaming technology. Mainly, bubbles with different diameters, such as 100 μm and 160 μm, were produced by introducing an optimized nitrogen gas and gelatin solution at an optimized flow rate, and N₂/gelatin bubbles were formed. Furthermore, a cross-linking agent (1-ethyl-3-(3-dimethyl aminopropyl)-carbodiimide, EDC) was employed for the cross-linking reaction of the gelatin-based hydrogel scaffold with uniform bubbles, and then the interface between the close cells were broken by degassing. The pore uniformity of the gelatin-based hydrogel scaffolds was confirmed by use of a bright field microscope, conjugate focus microscope and scanning electron microscope. The in vitro degradation rate, mechanical properties, and swelling rate of gelatin-based hydrogel scaffolds with highly uniform pore size were studied. Rabbit knee cartilage was cultured, and its extracellular matrix content was analyzed. Histological analysis and immunofluorescence staining were employed to confirm the activity of the rabbit knee chondrocytes. The chondrocytes were seeded into the resulting 3D porous gelatin-based hydrogel scaffolds. The growth conditions of the chondrocyte culture on the resulting 3D porous gelatin-based hydrogel scaffolds were evaluated by MTT analysis, live/dead cell activity analysis, and extracellular matrix content analysis. Additionally, a dynamic culture of cartilage tissue was performed, and the expression of cartilage-specific proteins within the culture time was studied by immunofluorescence staining analysis. The gelatin-based hydrogel scaffold encouraged chondrocyte proliferation, promoting the expression of collagen type II, aggrecan, and sox9 while retaining the structural stability and durability of the cartilage after dynamic compression and promoting cartilage repair. Full article

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13 pages, 2801 KiB

Open AccessArticle

Regiospecific Grafting of Chitosan Oligomers Brushes onto Silicon Wafers

by Cyrielle Garreau, Corinne Gablin, Didier Léonard, Thierry Delair, Guillaume Sudre and Stéphane Trombotto

Int. J. Mol. Sci. 2022, 23(14), 8013; https://doi.org/10.3390/ijms23148013 - 20 Jul 2022

Cited by 1 | Viewed by 1451

Abstract

The functionalization of surfaces using chitosan oligomers is of great interest for a wide range of applications in biomaterial and biomedical fields, as chitosan oligomers can provide various functional properties including biocompatibility, wetting, adhesion, and antibacterial activity. In this study, an innovative process [...] Read more.

The functionalization of surfaces using chitosan oligomers is of great interest for a wide range of applications in biomaterial and biomedical fields, as chitosan oligomers can provide various functional properties including biocompatibility, wetting, adhesion, and antibacterial activity. In this study, an innovative process for the regiospecific chemical grafting of reducing-end-modified chitosan oligomers brushes onto silicon wafers is described. Chitosan oligomers (COS) with well-defined structural parameters (average DP ~19 and DA ~0%) and bearing a 2,5-anhydro-d-mannofuranose (amf) unit at the reducing end were obtained via nitrous acid depolymerization of chitosan. After a silanization step where silicon wafers were modified with aromatic amine derivatives, grafting conditions were studied to optimize the reductive amination between aldehydes of amf-terminated COS and aromatic amines of silicon wafers. Functionalized surfaces were fully characterized by AFM, ATR-FTIR, ellipsometry, contact angle measurement, and ToF-SIMS techniques. Smooth surfaces were obtained with a COS layer about 3 nm thick and contact angle values between 72° and 76°. Furthermore, it was shown that the addition of the reducing agent NaBH₃CN could positively improve the COS grafting density and/or led to a better stability of the covalent grafting to hydrolysis. Finally, this study also showed that this grafting process is also efficient for chitosan oligomers of higher DA (i.e., ~21%). Full article

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26 pages, 8056 KiB

Open AccessArticle

Synthesis of Shape-Memory Polyurethanes: Combined Experimental and Simulation Studies

by Karolina Rolińska, Magdalena Mazurek-Budzyńska, Paweł G. Parzuchowski, Dominik Wołosz, Maria Balk, Krzysztof Gorący, Miroslawa El Fray, Piotr Polanowski and Andrzej Sikorski

Int. J. Mol. Sci. 2022, 23(13), 7064; https://doi.org/10.3390/ijms23137064 - 25 Jun 2022

Cited by 2 | Viewed by 1961

Abstract

The presented research focuses on the synthesis and structure–properties relationship of poly(carbonate-urea-urethane) (PCUU) systems including investigations on shape-memory effect capability. Furthermore, we approached the topic from a broader perspective by conducting extensive analysis of the relationship between the synthesized compounds and the results [...] Read more.

The presented research focuses on the synthesis and structure–properties relationship of poly(carbonate-urea-urethane) (PCUU) systems including investigations on shape-memory effect capability. Furthermore, we approached the topic from a broader perspective by conducting extensive analysis of the relationship between the synthesized compounds and the results of computer simulations by means of the Monte Carlo method. For the first time, by using a unique simulation tool, the dynamic lattice liquid model (DLL), all steps of multi-step synthesis of these materials were covered by the simulations. Furthermore, broad thermal, mechanical, and thermomechanical characterization of synthesized PCUUs was performed, as well as determining the shape-memory properties. PCUUs exhibited good mechanical properties with a tensile strength above 20 MPa, elongation at break around 800%, and an exhibited shape-memory effect with shape fixity and shape recovery ratios above 94% and 99%, respectively. The dynamic lattice liquid model was employed to show the products and their molar mass distribution, as well as monomer conversion or the dispersity index for individual reaction steps. The results obtained in the following manuscript allow the planning of syntheses for the PCUUs of various structures, including crosslinked and soluble systems, which can provide a broad variety of applications of these materials, as well as a better understanding of the composition–properties relationship. Full article

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18 pages, 766 KiB

Open AccessReview

Chitosan and Chitooligosaccharide: The Promising Non-Plant-Derived Prebiotics with Multiple Biological Activities

by Zhiwei Guan and Qiang Feng

Int. J. Mol. Sci. 2022, 23(12), 6761; https://doi.org/10.3390/ijms23126761 - 17 Jun 2022

Cited by 39 | Viewed by 3837

Abstract

Biodegradable chitin is the second-most abundant natural polysaccharide, widely existing in the exoskeletons of crabs, shrimps, insects, and the cell walls of fungi. Chitosan and chitooligosaccharide (COS, also named chitosan oligosaccharide) are the two most important deacetylated derivatives of chitin. Compared with chitin, [...] Read more.

Biodegradable chitin is the second-most abundant natural polysaccharide, widely existing in the exoskeletons of crabs, shrimps, insects, and the cell walls of fungi. Chitosan and chitooligosaccharide (COS, also named chitosan oligosaccharide) are the two most important deacetylated derivatives of chitin. Compared with chitin, chitosan and COS not only have more satisfactory physicochemical properties but also exhibit additional biological activities, which cause them to be widely applied in the fields of food, medicine, and agriculture. Additionally, due to their significant ability to improve gut microbiota, chitosan and COS are deemed prospective prebiotics. Here, we introduced the production, physicochemical properties, applications, and pharmacokinetic characteristics of chitosan and COS. Furthermore, we summarized the latest research on their antioxidant, anti-inflammatory, and antimicrobial activities. Research progress on the prebiotic functions of chitosan and COS is particularly reviewed. We creatively analyzed and discussed the mechanisms and correlations underlying these activities of chitosan and COS and their physicochemical properties. Our work enriched people’s understanding of these non-plant-derived prebiotics. Based on this review, the future directions of research on chitosan and COS are explored. Collectively, optimizing the production technology of chitin derivatives and enriching understanding of their biological functions will shed more light on their capability to improve human health. Full article

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11 pages, 2083 KiB

Open AccessArticle

Effect of PEGylation on the Drug Release Performance and Hemocompatibility of Photoresponsive Drug-Loading Platform

by Hayato L. Mizuno, Yasutaka Anraku, Ichiro Sakuma and Yuki Akagi

Int. J. Mol. Sci. 2022, 23(12), 6686; https://doi.org/10.3390/ijms23126686 - 15 Jun 2022

Cited by 3 | Viewed by 1824

Abstract

Coronary stenosis has been one of the most common heart diseases that drastically increases the risk of fatal disorders such as heart attack. Angioplasty using drug coated balloons (DCB) has been one of the most safe and promising treatments. To minimize the risk [...] Read more.

Coronary stenosis has been one of the most common heart diseases that drastically increases the risk of fatal disorders such as heart attack. Angioplasty using drug coated balloons (DCB) has been one of the most safe and promising treatments. To minimize the risk of thrombosis of such DCBs during intervention, a different approach that can secure high hemocompatibility under blood flow is necessary. Here we report a method of improving the photoresponsive platform’s hemocompatibility by conjugating polyethylene glycol (PEG), onto the functional groups located at the balloon surface. In this study, latex microbeads were used as models for balloons to enable precise observation of its surface under microscopy. These beads were decorated with PEG polymers of a variety of lengths and grafting densities, along with the Cy5-Photoclevable (PC) linker conjugate to mimic drugs to be loaded onto the platform. Results showed that PEG length and grafting density are both critical factors that alter not only its hemocompatibility, but also the drug load and release efficiency of such platform. Thus, although further investigation is necessary to optimize the tradeoff between hemocompatibility, drug load, and release efficiency, it is safe to conclude that PEGylation of DCB surface is an effective method of enhancing and maintaining high hemocompatibility to minimize the risk of thrombosis during angioplasty. Full article

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18 pages, 3140 KiB

Open AccessArticle

Modeling and Optimization of β-Galactosidase Entrapping in Polydimethylsiloxane-Modified Silica Composites

by Leszek Kadziński, Robert Łyżeń, Katarzyna Bury and Bogdan Banecki

Int. J. Mol. Sci. 2022, 23(10), 5395; https://doi.org/10.3390/ijms23105395 - 12 May 2022

Cited by 2 | Viewed by 1614

Abstract

Protein entrapment has multiple applications in enzymatic hydrolysis, drug delivery, etc. Here, we report the studies that successfully utilized the Box–Behnken design to model and optimize the parameters of β-galactosidase entrapment in sol–gel-derived silica composites. We have also demonstrated the influence of polymer–polydimethylsiloxane [...] Read more.

Protein entrapment has multiple applications in enzymatic hydrolysis, drug delivery, etc. Here, we report the studies that successfully utilized the Box–Behnken design to model and optimize the parameters of β-galactosidase entrapment in sol–gel-derived silica composites. We have also demonstrated the influence of polymer–polydimethylsiloxane as a composite modifying agent on the activity of entrapped enzymes. We have determined how different sol-gel process parameters influence the activity of entrapped enzymes. The highest impact on β-galactosidase activity was exerted by the water:tetramethoxysilane ratio, followed by polydimethylsiloxane content. Optimized synthesis parameters have been utilized to obtain a composite with maximum β-galactosidase activity. Performed porosity studies have shown that the addition of polydimethylsiloxane increased the pore diameter. Microscopy studies demonstrated that polydimethylsiloxane-modified composites are softer and less rough. Studies of β-galactosidase activity using the o-NPG test showed statistically significant shifts in the enzyme temperature and pH profiles compared to the soluble form. An improvement in the reusability of the enzyme and a significant increase in the thermal stability was also observed. When lactose was used, a strong correlation was observed between the substrate concentration and the type of the catalyzed reaction. Moreover, we have demonstrated that the yields and rates of both lactose hydrolysis and galactooligosaccharides formation were correlated with reaction temperature and with the presence of polydimethylsiloxane. All these findings provide the opportunity for industrial use of optimized PDMS-modified silica composites in lactose elimination from dairy products, e.g., milk or whey. Full article

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10 pages, 1188 KiB

Open AccessBrief Report

Optimizing Chain Topology of Bottle Brush Copolymer for Promoting the Disorder-to-Order Transition

by Jihoon Park, Hyun-Woo Shin, Joona Bang and June Huh

Int. J. Mol. Sci. 2022, 23(10), 5374; https://doi.org/10.3390/ijms23105374 - 11 May 2022

Viewed by 1656

Abstract

The order-disorder transitions (ODT) of core-shell bottle brush copolymer and its structural isomers were investigated by dissipative particle dynamics simulations and theoretically by random phase approximation. Introducing a chain topology parameter

λ

which parametrizes linking points between M diblock chains each with N [...] Read more.

The order-disorder transitions (ODT) of core-shell bottle brush copolymer and its structural isomers were investigated by dissipative particle dynamics simulations and theoretically by random phase approximation. Introducing a chain topology parameter

λ

which parametrizes linking points between M diblock chains each with N monomers, the degree of incompatibility at ODT (

{(χ N)}_{ODT}

;

χ

being the Flory–Huggins interaction parameter between constituent monomers) was predicted as a function of chain topology parameter (

λ

) and the number of linked diblock chains per bottle brush copolymer (M). It was found that there exists an optimal chain topology about

λ

at which

{(χ N)}_{ODT}

gets a minimum while the domain spacing remains nearly unchanged. The prediction provides a theoretical guideline for designing an optimal copolymer architecture capable of forming sub-10 nm periodic structures even with non-high

χ

components. Full article

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22 pages, 6237 KiB

Open AccessArticle

Materials Based on Quaternized Polysulfones with Potential Applications in Biomedical Field: Structure–Properties Relationship

by Alexandra Bargan, Mihaela Dorina Onofrei, Iuliana Stoica, Florica Doroftei, Simona Dunca and Anca Filimon

Int. J. Mol. Sci. 2022, 23(9), 4721; https://doi.org/10.3390/ijms23094721 - 25 Apr 2022

Cited by 1 | Viewed by 1504

Abstract

Starting from the bactericidal properties of functionalized polysulfone (PSFQ) and due to its excellent biocompatibility, biodegradability, and performance in various field, cellulose acetate phthalate (CAP) and polyvinyl alcohol (PVA), as well as their blends (PSFQ/CAP and PSFQ/PVA), have been tested to evaluate their [...] Read more.

Starting from the bactericidal properties of functionalized polysulfone (PSFQ) and due to its excellent biocompatibility, biodegradability, and performance in various field, cellulose acetate phthalate (CAP) and polyvinyl alcohol (PVA), as well as their blends (PSFQ/CAP and PSFQ/PVA), have been tested to evaluate their applicative potential in the biomedical field. In this context, because the polymer processing starts from the solution phase, in the first step, the rheological properties were followed in order to assess and control the structural parameters. The surface chemistry analysis, surface properties, and antimicrobial activity of the obtained materials were investigated in order to understand the relationship between the polymers’ structure–surface properties and organization form of materials (fibers and/or films), as important indicators for their future applications. Using the appropriate organization form of the polymers, the surface morphology and performance, including wettability and water permeation, were improved and controlled—these being the desired and needed properties for applications in the biomedical field. Additionally, after antimicrobial activity testing against different bacteria strains, the control of the inhibition mechanism for the analyzed microorganisms was highlighted, making it possible to choose the most efficient polymers/blends and, consequently, the efficiency as biomaterials in targeted applications. Full article

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13 pages, 2082 KiB

Open AccessArticle

Unsaturated Copolyesters from Macrolactone/Norbornene: Toward Reaction Kinetics of Metathesis Copolymerization Using Ruthenium Carbene Catalysts

by Araceli Martínez, Daniel Zárate-Saldaña, Joel Vargas and Arlette A. Santiago

Int. J. Mol. Sci. 2022, 23(9), 4521; https://doi.org/10.3390/ijms23094521 - 20 Apr 2022

Viewed by 1617

Abstract

Unsaturated copolyesters are of great interest in polymer science due to their broad potential applications and sustainability. Copolyesters were synthesized from the ring-opening metathesis copolymerization of ω-6-hexadecenlactone (HDL) and norbornene (NB) using ruthenium-alkylidene [Ru(Cl₂)(=CHPh)(1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)(PCy₃)] (Ru1 [...] Read more.

Unsaturated copolyesters are of great interest in polymer science due to their broad potential applications and sustainability. Copolyesters were synthesized from the ring-opening metathesis copolymerization of ω-6-hexadecenlactone (HDL) and norbornene (NB) using ruthenium-alkylidene [Ru(Cl₂)(=CHPh)(1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)(PCy₃)] (Ru1), [Ru(Cl)₂(=CHPh)(PCy₃)₂] (Ru2), and ruthenium-vinylidene [RuCl₂(=C=CH(p-C₆H₄CF₃))(PCy₃)₂] (Ru3) catalysts, respectively, yielding HDL-NB copolymers with different ratios of the monomer HDL in the feed. The activity of N-heterocyclic-carbene (NHC) (Ru1) and phosphine (Ru2 and Ru3) ligands containing ruthenium-carbene catalysts were evaluated in the synthesis of copolymer HDL-NB. The catalysts Ru1 with an NHC ligand showed superior activity and stability over catalysts Ru2 and Ru3 bearing PCy₃ ligands. The incorporation of the monomers in the copolymers determined by ¹H-NMR spectroscopy was similar to that of the HDL-NB values in the feed. Experiments, at distinct monomer molar ratios, were carried out using the catalysts Ru1–Ru3 to determine the copolymerization reactivity constants by applying the Mayo–Lewis and Fineman–Ross methods. The copolymer distribution under equilibrium conditions was studied by the ¹³C NMR spectra, indicating that the copolymer HDL-NB is a gradient copolymer. The main factor determining the decrease in melting temperature is the inclusion of norbornene units, indicating that the PNB units permeate trough the HDL chains. The copolymers with different molar ratios [HDL]/[NB] have good thermal stability up to 411 °C in comparison with the homopolymer PHDL (384 °C). Further, the stress–strain measurements in tension for these copolymers depicted the appreciable increment in stress values as the NB content increases. Full article

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17 pages, 9274 KiB

Open AccessArticle

Nickel(II) Coordination Polymers Supported by Bis-pyridyl-bis-amide and Angular Dicarboxylate Ligands: Role of Ligand Flexibility in Iodine Adsorption

by Wei-Te Lee, Tsung-Te Liao and Jhy-Der Chen

Int. J. Mol. Sci. 2022, 23(7), 3603; https://doi.org/10.3390/ijms23073603 - 25 Mar 2022

Cited by 5 | Viewed by 1903

Abstract

Reactions of N‚N’-bis(3-pyridylmethyl)oxalamide (L¹), N‚N’-bis(4-pyridylmethyl)oxalamide (L²), or N,N’-bis(3-pyridylmethyl)adipoamide) (L³) with angular dicarboxylic acids and Ni(II) salts under hydro(solvo)thermal conditions afforded a series of coordination polymers: {[Ni(L¹)(OBA)(H₂O)]·H [...] Read more.

Reactions of N‚N’-bis(3-pyridylmethyl)oxalamide (L¹), N‚N’-bis(4-pyridylmethyl)oxalamide (L²), or N,N’-bis(3-pyridylmethyl)adipoamide) (L³) with angular dicarboxylic acids and Ni(II) salts under hydro(solvo)thermal conditions afforded a series of coordination polymers: {[Ni(L¹)(OBA)(H₂O)]·H₂O}_n (H₂OBA = 4,4-oxydibenzoic acid), 1, {[Ni(L¹)(SDA)(H₂O)₂]·H₂O·CH₃OH}_n (H₂SDA = 4,4-sulfonyldibenzoic acid), 2, {[Ni(L²)(OBA)]·C₂H₅OH}_n, 3, {[Ni(L²)(OBA)]·CH₃OH}_n, 4, {[Ni₂(L²)(SDA)₂(H₂O)₃]·5H₂O}_n, 5, {[Ni₂(L²)(SDA)₂(H₂O)₃]·H₂O·2C₂H₅OH}_n, 6, {[Ni(L³)(OBA)(H₂O)₂]·2H₂O}_n, 7, {[Ni(L³)(SDA)(H₂O)₂]·2H₂O}_n, 8, and {[Ni(L³)₀.₅(SDA)(H₂O)₂]·0.5C₂H₅OH}_n, 9, which have been structurally characterized by using single-crystal X-ray crystallography. Complex 1 exhibits an interdigitated 2D layer with the 2,4L2 topology and 2 is a 2D layer with the sql topology, while 3 and 4 are 3D frameworks resulting from polycatenated 2D nets with the sql topology and 5 and 6 are 2-fold interpenetrated 3D frameworks with the dia topology. Complexes 7 and 8 are 1D looped chains and 9 is a 2D layer with the 3,4L13 topology. The various structural types in 1–9 indicate that the structural diversity is subject to the flexibility and donor atom position of the neutral spacer ligands and the identity of the angular dicarboxylate ligands, while the role of the solvent is uncertain. The iodine adsorption of 1–9 was also investigated, demonstrating that that the flexibility of the spacer L¹–L³ ligands can be an important factor that governs the feasibility of the iodine adsorption. Moreover, complex 9 shows a better iodine adsorption and encapsulates 166.55 mg g⁻¹ iodine in the vapor phase at 60 °C, which corresponded to 0.38 molecules of iodine per formula unit. Full article

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12 pages, 3142 KiB

Open AccessArticle

Controlling the Phase Behavior and Reflection of Main-Chain Cholesteric Oligomers Using a Smectic Monomer

by Lansong Yue, Xiuyi Shi, Guofu Zhou and Laurens T. de Haan

Int. J. Mol. Sci. 2022, 23(6), 3275; https://doi.org/10.3390/ijms23063275 - 18 Mar 2022

Cited by 3 | Viewed by 1946

Abstract

Cholesteric liquid crystals (CLCs) are a significant class of temperature-responsive photonic materials that have the ability to selectively reflect light of a specific wavelength. However, the fabrication of main-chain CLC oligomers with dramatic reflection band variation upon varying the temperatures remains a challenge. [...] Read more.

Cholesteric liquid crystals (CLCs) are a significant class of temperature-responsive photonic materials that have the ability to selectively reflect light of a specific wavelength. However, the fabrication of main-chain CLC oligomers with dramatic reflection band variation upon varying the temperatures remains a challenge. Here, a feasible method for improving and controlling the responsiveness of main-chain cholesteric liquid crystal oligomers by the incorporation of a smectic monomer is reported. The smectic monomer strengthens the smectic character of the oligomers and enhances the magnitude of the change of the pitch as a function of temperature upon approaching the cholesteric–smectic phase transition temperature. The central wavelength of the reflection band can be easily modified by mixing in an additional chiral dopant. This promising method will open the door to the preparation of temperature-responsive photonic devices with excellent responsiveness. Full article

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13 pages, 4116 KiB

Open AccessArticle

Use of Nanocellulose to Produce Water-Based Conductive Inks with Ag NPs for Printed Electronics

by Sandra Martinez-Crespiera, Belén Pepió-Tàrrega, Rosa M. González-Gil, Francisco Cecilia-Morillo, Javier Palmer, Ana M. Escobar, Sirio Beneitez-Álvarez, Tiffany Abitbol, Andreas Fall, Christian Aulin, Yuval Nevo, Valerio Beni, Enrico Tolin and Achim Bahr

Int. J. Mol. Sci. 2022, 23(6), 2946; https://doi.org/10.3390/ijms23062946 - 09 Mar 2022

Cited by 5 | Viewed by 2237

Abstract

The need for more sustainable printed electronics has emerged in the past years. Due to this, the use of nanocellulose (NC) extracted from cellulose has recently been demonstrated to provide interesting materials such as functional inks and transparent flexible films due to its [...] Read more.

The need for more sustainable printed electronics has emerged in the past years. Due to this, the use of nanocellulose (NC) extracted from cellulose has recently been demonstrated to provide interesting materials such as functional inks and transparent flexible films due to its properties. Its high specific surface area together with the high content of reactive hydroxyl groups provide a highly tailorable surface chemistry with applications in ink formulations as a stabilizing, capping, binding and templating agent. Moreover, NC mechanical, physical and thermal properties (high strength, low porosity and high thermal stability, respectively) provide an excellent alternative for the currently used plastic films. In this work, we present a process for the production of water-based conductive inks that uses NC both as a template for silver nanoparticles (Ag NPs) formation and as an ink additive for ink formulation. The new inks present an electrical conductivity up to 2 × 10⁶ S/m, which is in the range of current commercially available conductive inks. Finally, the new Ag NP/NC-based conductive inks have been tested to fabricate NFC antennas by screen-printing onto NC-coated paper, demonstrating to be operative. Full article

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13 pages, 18519 KiB

Open AccessArticle

Effect of Irradiation on Structural Changes of Levan

by Dorota Chelminiak-Dudkiewicz, Aleksander Smolarkiewicz-Wyczachowski, Katarzyna Wegrzynowska-Drzymalska and Marta Ziegler-Borowska

Int. J. Mol. Sci. 2022, 23(5), 2463; https://doi.org/10.3390/ijms23052463 - 23 Feb 2022

Cited by 5 | Viewed by 1499

Abstract

Levan, as a biocompatible and renewable biopolymer with anticancer properties, is a promising candidate for a wide range of applications in various fields of industry. However, in the literature, there is a lack of information about its behavior under the influence of UV [...] Read more.

Levan, as a biocompatible and renewable biopolymer with anticancer properties, is a promising candidate for a wide range of applications in various fields of industry. However, in the literature, there is a lack of information about its behavior under the influence of UV irradiation, which may limit its potential application, including medical science. Therefore, this study describes the effects of irradiation on the structural properties of levan. This type of fructan was subjected to stability tests under radiation conditions using LED and polychromatic lamps. The results showed that the photodegradation of levan irradiated with a polychromatic light occurs faster and more efficiently than the photodegradation of levan irradiated with an LED lamp. Furthermore, AFM analysis showed that the surface became smoother after irradiation, as evidenced by decreasing values of roughness parameters. Moreover, UV irradiation causes the decrease of total surface free energy and both its components in levan; however, more significant changes occur during irradiation of the sample with a polychromatic lamp. Full article

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16 pages, 3335 KiB

Open AccessArticle

Mechanisms Affecting Physical Aging and Swelling by Blending an Amphiphilic Component

by Shifen Huang, Yiming Zhang, Chenhong Wang, Qinghua Xia, Muhammad Saif Ur Rahman, Hao Chen, Charles Han, Ying Liu and Shanshan Xu

Int. J. Mol. Sci. 2022, 23(4), 2185; https://doi.org/10.3390/ijms23042185 - 16 Feb 2022

Cited by 6 | Viewed by 1712

Abstract

Polymer blending is a promising method to overcome stability obstacles induced by physical aging and swelling of implant scaffolds prepared from amorphous polymers in biomedical application, since it will not bring potential toxicity compared with chemical modification. However, the mechanism of polymer blending [...] Read more.

Polymer blending is a promising method to overcome stability obstacles induced by physical aging and swelling of implant scaffolds prepared from amorphous polymers in biomedical application, since it will not bring potential toxicity compared with chemical modification. However, the mechanism of polymer blending still remains unclearly explained in existing studies that fail to provide theoretical references in material R&D processes for stability improvement of the scaffold during ethylene oxide (EtO) sterilization, long-term storage, and clinical application. In this study, amphiphilic poly(ethylene glycol)-co-poly(lactic acid) (PELA) was blended with amorphous poly(lactic-co-glycolic acid) (PLGA) because of its good miscibility so as to adjust the glass transition temperature (Tg) and hydrophilicity of electrospun PLGA membranes. By characterizing the morphological stability and mechanical performance, the chain movement and the glass transition behavior of the polymer during the physical aging and swelling process were studied. This study revealed the modification mechanism of polymer blending at the molecular chain level, which will contribute to stability improvement and performance adjustment of implant scaffolds in biomedical application. Full article

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25 pages, 5471 KiB

Open AccessReview

Gemini and Bicephalous Surfactants: A Review on Their Synthesis, Micelle Formation, and Uses

by Lluvia Guerrero-Hernández, Héctor Iván Meléndez-Ortiz, Gladis Y. Cortez-Mazatan, Sandra Vaillant-Sánchez and René D. Peralta-Rodríguez

Int. J. Mol. Sci. 2022, 23(3), 1798; https://doi.org/10.3390/ijms23031798 - 04 Feb 2022

Cited by 21 | Viewed by 4726

Abstract

The use of surfactants in polymerization reactions is particularly important, mainly in emulsion polymerizations. Further, micelles from biocompatible surfactants find use in pharmaceutical dosage forms. This paper reviews recent developments in the synthesis of novel gemini and bicephalous surfactants, micelle formation, and their [...] Read more.

The use of surfactants in polymerization reactions is particularly important, mainly in emulsion polymerizations. Further, micelles from biocompatible surfactants find use in pharmaceutical dosage forms. This paper reviews recent developments in the synthesis of novel gemini and bicephalous surfactants, micelle formation, and their applications in polymer and nanoparticle synthesis, oil recovery, catalysis, corrosion, protein binding, and biomedical area, particularly in drug delivery. Full article

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13 pages, 1515 KiB

Open AccessReview

Implantable Immunosuppressant Delivery to Prevent Rejection in Transplantation

by Madonna Rica Anggelia, Ren-Wen Huang, Hui-Yun Cheng, Chih-Hung Lin and Cheng-Hung Lin

Int. J. Mol. Sci. 2022, 23(3), 1592; https://doi.org/10.3390/ijms23031592 - 29 Jan 2022

Cited by 8 | Viewed by 3266

Abstract

An innovative immunosuppressant with a minimally invasive delivery system has emerged in the biomedical field. The application of biodegradable and biocompatible polymer forms, such as hydrogels, scaffolds, microspheres, and nanoparticles, in transplant recipients to control the release of immunosuppressants can minimize the risk [...] Read more.

An innovative immunosuppressant with a minimally invasive delivery system has emerged in the biomedical field. The application of biodegradable and biocompatible polymer forms, such as hydrogels, scaffolds, microspheres, and nanoparticles, in transplant recipients to control the release of immunosuppressants can minimize the risk of developing unfavorable conditions. In this review, we summarized several studies that have used implantable immunosuppressant delivery to release therapeutic agents to prolong allograft survival. We also compared their applications, efficacy, efficiency, and safety/side effects with conventional therapeutic-agent administration. Finally, challenges and the future prospective were discussed. Collectively, this review will help relevant readers understand the different approaches to prevent transplant rejection in a new era of therapeutic agent delivery. Full article

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2021

Jump to: 2023, 2022

21 pages, 3919 KiB

Open AccessArticle

Zein-Based Films Containing Monolaurin/Eugenol or Essential Oils with Potential for Bioactive Packaging Application

by Jana Sedlarikova, Magda Janalikova, Petra Peer, Lucie Pavlatkova, Antonin Minarik and Pavel Pleva

Int. J. Mol. Sci. 2022, 23(1), 384; https://doi.org/10.3390/ijms23010384 - 29 Dec 2021

Cited by 11 | Viewed by 2836

Abstract

Zein is renewable plant protein with valuable film-forming properties that can be used as a packaging material. It is known that the addition of natural cross-linkers can enhance a film’s tensile properties. In this study, we aimed to prepare antimicrobial zein-based films enriched [...] Read more.

Zein is renewable plant protein with valuable film-forming properties that can be used as a packaging material. It is known that the addition of natural cross-linkers can enhance a film’s tensile properties. In this study, we aimed to prepare antimicrobial zein-based films enriched with monolaurin, eugenol, oregano, and thyme essential oil. Films were prepared using the solvent casting technique from ethanol solution. Their physicochemical properties were investigated using structural, morphological, and thermal techniques. Polar and dispersive components were analyzed using two models to evaluate the effects on the surface free energy values. The antimicrobial activity was proven using a disk diffusion method and the suppression of bacterial growth was confirmed via a growth kinetics study with the Gompertz function. The films’ morphological characteristics led to systems with uniform distribution of essential oils or eugenol droplets combined with a flat-plated structure of monolaurin. A unique combination of polyphenolic eugenol and amphiphilic monoglyceride provided highly stretchable films with enhanced barrier properties and efficiency against Gram-positive and Gram-negative bacteria, yeasts, and molds. The prepared zein-based films with tunable surface properties represent an alternative to non-renewable resources with a potential application as active packaging materials. Full article

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12 pages, 1038 KiB

Open AccessReview

Design of Polymeric Films for Antioxidant Active Food Packaging

by Wing-Fu Lai

Int. J. Mol. Sci. 2022, 23(1), 12; https://doi.org/10.3390/ijms23010012 - 21 Dec 2021

Cited by 29 | Viewed by 3321

Abstract

Antioxidant active food packaging can extend the shelf life of foods by retarding the rate of oxidation reactions of food components. Although significant advances in the design and development of polymeric packaging films loaded with antioxidants have been achieved over the last several [...] Read more.

Antioxidant active food packaging can extend the shelf life of foods by retarding the rate of oxidation reactions of food components. Although significant advances in the design and development of polymeric packaging films loaded with antioxidants have been achieved over the last several decades, few of these films have successfully been translated from the laboratory to commercial applications. This article presents a snapshot of the latest advances in the design and applications of polymeric films for antioxidant active food packaging. It is hoped that this article will offer insights into the optimisation of the performance of polymeric films for food packaging purposes and will facilitate the translation of those polymeric films from the laboratory to commercial applications in the food industry. Full article

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18 pages, 3750 KiB

Open AccessArticle

Study of the Spatio-Chemical Heterogeneity of Tannin-Furanic Foams: From 1D FTIR Spectroscopy to 3D FTIR Micro-Computed Tomography

by Nicola Cefarin, Diana E. Bedolla, Artur Surowka, Sandro Donato, Thomas Sepperer, Gianluca Tondi, Diego Dreossi, Nicola Sodini, Giovanni Birarda and Lisa Vaccari

Int. J. Mol. Sci. 2021, 22(23), 12869; https://doi.org/10.3390/ijms222312869 - 28 Nov 2021

Cited by 7 | Viewed by 2553

Abstract

Tannin-furanic rigid foams are bio-based copolymers of tannin plant extract and furfuryl alcohol, promising candidates to replace synthetic insulation foams, as for example polyurethanes and phenolics, in eco-sustainable buildings thanks to their functional properties, such as lightness of the material and fire resistance. [...] Read more.

Tannin-furanic rigid foams are bio-based copolymers of tannin plant extract and furfuryl alcohol, promising candidates to replace synthetic insulation foams, as for example polyurethanes and phenolics, in eco-sustainable buildings thanks to their functional properties, such as lightness of the material and fire resistance. Despite their relevance as environmental-friendly alternatives to petroleum derivatives, many aspects of the polymerization chemistry still remain unclear. One of the open issues is on the spatial heterogeneity of the foam, i.e., whether the foam constituents prevalently polymerize in spatially segregated blocks or distribute almost homogenously in the foam volume. To address this matter, here we propose a multiscale FTIR study encompassing 1D FTIR spectroscopy, 2D FTIR imaging and 3D FTIR micro-tomography (FTIR-μCT) on tannin-furanic rigid foams obtained by varying the synthesis parameters in a controlled way. Thanks to the implementation of the acquisition and processing pipeline of FTIR-μCT, we were able for the first time to demonstrate that the polymer formulations influence the spatial organization of the foam at the microscale and, at the same time, prove the reliability of FTIR-μCT data by comparing 2D FTIR images and the projection of the 3D chemical images on the same plane. Full article

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13 pages, 5615 KiB

Open AccessArticle

Towards Understanding the Chemical Structure Modification of EVA Copolymer upon MAPLE Processing of Thin Films

by Agata Niemczyk, Simona Brajnicov, Veronica Satulu, Jolanta Baranowska, Bogdana Mitu and Maria Dinescu

Int. J. Mol. Sci. 2021, 22(21), 11686; https://doi.org/10.3390/ijms222111686 - 28 Oct 2021

Cited by 1 | Viewed by 1797

Abstract

A series of coatings from poly(ethylene-co-vinyl acetate) (EVA) were obtained using the matrix-assisted pulsed laser evaporation (MAPLE) technique. By changing the process parameters, i.e., laser fluence and EVA co-polymer concentration in the target, coatings with various morphologies and topographies were produced. [...] Read more.

A series of coatings from poly(ethylene-co-vinyl acetate) (EVA) were obtained using the matrix-assisted pulsed laser evaporation (MAPLE) technique. By changing the process parameters, i.e., laser fluence and EVA co-polymer concentration in the target, coatings with various morphologies and topographies were produced. The evaluation of the film structure was based on an analysis of optical and atomic force microscopy and profilometry measurements. A detailed chemical structure investigation, conducted based on Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra, revealed that although the general structure was preserved, some alterations of ethylene (Et) and vinyl acetate (VAc) blocks took place. The most noticeable change was in the ester group that was transformed into ketone and carboxyl groups; nevertheless, some changes in the aliphatic main chain were also present. The chemical structure changes in EVA coatings took place regardless of the process parameters used. The use of chloroform as a solvent to dissolve the EVA copolymer was indicated as a possible reason of the changes as well as the tendency of EVA macromolecules to form clusters. Nevertheless, due to low level of structure alteration, it has been shown that the MAPLE technique can be successfully used to obtain coatings from polymers with more complex structures, which are soluble in a limited number of solvents. Full article

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24 pages, 5413 KiB

Open AccessArticle

Prediction of Viscoelastic Properties of Enzymatically Crosslinkable Tyramine–Modified Hyaluronic Acid Solutions Using a Dynamic Monte Carlo Kinetic Approach

by Filippos F. Karageorgos and Costas Kiparissides

Int. J. Mol. Sci. 2021, 22(14), 7317; https://doi.org/10.3390/ijms22147317 - 07 Jul 2021

Cited by 5 | Viewed by 2694

Abstract

The present study deals with the mathematical modeling of crosslinking kinetics of polymer–phenol conjugates mediated by the Horseradish Peroxidase (HRP)-hydrogen peroxide (H₂O₂) initiation system. More specifically, a dynamic Monte Carlo (MC) kinetic model is developed to quantify the effects [...] Read more.

The present study deals with the mathematical modeling of crosslinking kinetics of polymer–phenol conjugates mediated by the Horseradish Peroxidase (HRP)-hydrogen peroxide (H₂O₂) initiation system. More specifically, a dynamic Monte Carlo (MC) kinetic model is developed to quantify the effects of crosslinking conditions (i.e., polymer concentration, degree of phenol substitution and HRP and H₂O₂ concentrations) on the gelation onset time; evolution of molecular weight distribution and number and weight average molecular weights of the crosslinkable polymer chains and gel fraction. It is shown that the MC kinetic model can faithfully describe the crosslinking kinetics of a finite sample of crosslinkable polymer chains with time, providing detailed molecular information for the crosslinkable system before and after the gelation point. The MC model is validated using experimental measurements on the crosslinking of a tyramine modified Hyaluronic Acid (HA-Tyr) polymer solution reported in the literature. Based on the rubber elasticity theory and the MC results, the dynamic evolution of hydrogel viscoelastic and molecular properties (i.e., number average molecular weight between crosslinks, M_c, and hydrogel mesh size, ξ) are calculated. Full article

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15 pages, 3611 KiB

Open AccessArticle

Thermally-Induced Shape-Memory Behavior of Degradable Gelatin-Based Networks

by Axel T. Neffe, Candy Löwenberg, Konstanze K. Julich-Gruner, Marc Behl and Andreas Lendlein

Int. J. Mol. Sci. 2021, 22(11), 5892; https://doi.org/10.3390/ijms22115892 - 31 May 2021

Cited by 10 | Viewed by 4366

Abstract

Shape-memory hydrogels (SMH) are multifunctional, actively-moving polymers of interest in biomedicine. In loosely crosslinked polymer networks, gelatin chains may form triple helices, which can act as temporary net points in SMH, depending on the presence of salts. Here, we show programming and initiation [...] Read more.

Shape-memory hydrogels (SMH) are multifunctional, actively-moving polymers of interest in biomedicine. In loosely crosslinked polymer networks, gelatin chains may form triple helices, which can act as temporary net points in SMH, depending on the presence of salts. Here, we show programming and initiation of the shape-memory effect of such networks based on a thermomechanical process compatible with the physiological environment. The SMH were synthesized by reaction of glycidylmethacrylated gelatin with oligo(ethylene glycol) (OEG) α,ω-dithiols of varying crosslinker length and amount. Triple helicalization of gelatin chains is shown directly by wide-angle X-ray scattering and indirectly via the mechanical behavior at different temperatures. The ability to form triple helices increased with the molar mass of the crosslinker. Hydrogels had storage moduli of 0.27–23 kPa and Young’s moduli of 215–360 kPa at 4 °C. The hydrogels were hydrolytically degradable, with full degradation to water-soluble products within one week at 37 °C and pH = 7.4. A thermally-induced shape-memory effect is demonstrated in bending as well as in compression tests, in which shape recovery with excellent shape-recovery rates R_r close to 100% were observed. In the future, the material presented here could be applied, e.g., as self-anchoring devices mechanically resembling the extracellular matrix. Full article

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19 pages, 3834 KiB

Open AccessReview

Plastic Degradation by Extremophilic Bacteria

by Nikolina Atanasova, Stoyanka Stoitsova, Tsvetelina Paunova-Krasteva and Margarita Kambourova

Int. J. Mol. Sci. 2021, 22(11), 5610; https://doi.org/10.3390/ijms22115610 - 25 May 2021

Cited by 63 | Viewed by 11744

Abstract

Intensive exploitation, poor recycling, low repeatable use, and unusual resistance of plastics to environmental and microbiological action result in accumulation of huge waste amounts in terrestrial and marine environments, causing enormous hazard for human and animal life. In the last decades, much scientific [...] Read more.

Intensive exploitation, poor recycling, low repeatable use, and unusual resistance of plastics to environmental and microbiological action result in accumulation of huge waste amounts in terrestrial and marine environments, causing enormous hazard for human and animal life. In the last decades, much scientific interest has been focused on plastic biodegradation. Due to the comparatively short evolutionary period of their appearance in nature, sufficiently effective enzymes for their biodegradation are not available. Plastics are designed for use in conditions typical for human activity, and their physicochemical properties roughly change at extreme environmental parameters like low temperatures, salt, or low or high pH that are typical for the life of extremophilic microorganisms and the activity of their enzymes. This review represents a first attempt to summarize the extraordinarily limited information on biodegradation of conventional synthetic plastics by thermophilic, alkaliphilic, halophilic, and psychrophilic bacteria in natural environments and laboratory conditions. Most of the available data was reported in the last several years and concerns moderate extremophiles. Two main questions are highlighted in it: which extremophilic bacteria and their enzymes are reported to be involved in the degradation of different synthetic plastics, and what could be the impact of extremophiles in future technologies for resolving of pollution problems. Full article

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