Physically Cross-Linked Gels and Their Applications

A special issue of Gels (ISSN 2310-2861). This special issue belongs to the section "Gel Applications".

Deadline for manuscript submissions: 30 May 2024 | Viewed by 13695

Special Issue Editors


E-Mail Website
Guest Editor
Ufa Institute of Chemistry, Ufa Federal Research Centre of the Russian Academy of Sciences, 450054 Ufa, Russia
Interests: biopolymers; polyelectrolytes; hydrogels; chitosan; hyaluronic acid; drug delivery; rheology; cross-linking

E-Mail Website
Guest Editor
Ufa Institute of Chemistry, Ufa Federal Research Centre of the Russian Academy of Sciences, 450054 Ufa, Russia
Interests: chemical transformations of polymers (modification, destruction, stabilization); physiologically active polymers and polymer systems; technology of polymers and polymer materials

E-Mail Website
Guest Editor

Special Issue Information

Dear Colleagues,

This Special Issue is focused on physically cross-linked gels and their applications in various areas, including biomedicine, drug delivery, cosmetics, food technology, oil recovery, and other industries. A unique substance called gel was first prepared by the Scottish chemist Thomas Graham in the 19th century, namely, it was a physically cross-linked gelatin gel. In the 21st century, there is a rapid development in polymer and materials science, dedicated to the development of methods for the synthesis and optimization of conditions for the preparation of composite polymer materials with a nanoscale structure, as well as the study of their properties for various applications. Physically cross-linked gels have a number of advantages, including the simplicity of their preparation without the need for cross-linking agents. Different methods have been developed for preparing physical gels. Well-known examples of these systems include  formation of gels by alginates and pectinates in the presence of calcium ions due to ionic interactions; formation of poly(vinyl alcohol)-based cryogels via cross-linking due to crystallization; formation of gels based on amphiphilic block copolymers, such as Pluronics due to hydrophobic effects, and cross-linking due to protein-protein interactions. Physically cross-linked gels may also be prepared in the form of cryogels, aerogels, xerogels, films, micro- and nanogels, and hybrid materials in combination with micro- and nanoparticles. Although the use of synthetic polymers provides gels with controlled properties, the use of natural polymers improves the biocompatibility of the material and appears to be more environmentally friendly.

Our team of guest editors hopes that this Special Issue will attract submissions of high-quality reviews and original research manuscripts from the international community of researchers, specializing in different types of physical gels. We believe that physically cross-linked gels are not only interesting and promising objects for research, but also have a great potential for practical applications in various fields, expanding the capabilities of traditional objects and improving the quality of people's lives.

Dr. Regina R. Vildanova
Prof. Dr. Sergey V. Kolesov
Prof. Dr. Vitaliy V. Khutoryanskiy
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Gels is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • physical cross-linking
  • poly(vinyl alcohol)-based cryogels
  • hydrogels
  • aerogels
  • synthetic polymers
  • natural biopolymers
  • Pluronics
  • polyelectrolyte complex
  • molecular interactions
  • biomaterials
  • applications
  • rheology
  • drug delivery

Published Papers (9 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

16 pages, 4132 KiB  
Article
Fabrication of Alginate/Ozoile Gel Microspheres by Electrospray Process
by Gianluca Ciarleglio, Tiziana Russo, Elisa Toto and Maria Gabriella Santonicola
Gels 2024, 10(1), 52; https://doi.org/10.3390/gels10010052 - 11 Jan 2024
Cited by 1 | Viewed by 1038
Abstract
Natural polymers, such as alginate and chitosan, are widely exploited for drug delivery applications due to their biocompatibility, low toxicity, and sustainable sourcing. In this study, pH-responsive gel microspheres were fabricated from an alginate/Ozoile emulsion. Ozoile (Stable Ozonides) is a biological inducer, derived [...] Read more.
Natural polymers, such as alginate and chitosan, are widely exploited for drug delivery applications due to their biocompatibility, low toxicity, and sustainable sourcing. In this study, pH-responsive gel microspheres were fabricated from an alginate/Ozoile emulsion. Ozoile (Stable Ozonides) is a biological inducer, derived from olive oil, which stimulates the endogenous defense system by promoting the repair of tissue damage and restoration of proper physiology through the regulation of gene transcription. Here, the versatile and cost-effective electrospray technique without the use of organic solvents was used to fabricate alginate/Ozoile microspheres with high throughput. The process parameters (voltage, flow rate, and needle gauge) were optimized to obtain microspheres with good sphericity factor and tailored diameter (250–700 μm). The microspheres were additionally optimized through a chitosan coating to enhance their stability and regulate the gel matrix’s degradation process. Morphological analysis, FTIR spectroscopy, and degradation tests confirmed the structural integrity and pH-responsive behavior of the gel microspheres. This research offers a promising route for targeted drug delivery systems, particularly in applications related to the modulation of oxidative stress and management of inflammation. Full article
(This article belongs to the Special Issue Physically Cross-Linked Gels and Their Applications)
Show Figures

Graphical abstract

20 pages, 15454 KiB  
Article
Effect of Phytic Acid Addition on the Structure of Collagen-Hyaluronic Acid Composite Gel
by Yuliya Nashchekina, Evgeny Guryanov, Alexey Lihachev, Gleb Vaganov, Elena Popova, Natalya Mikhailova and Alexey Nashchekin
Gels 2023, 9(12), 963; https://doi.org/10.3390/gels9120963 - 08 Dec 2023
Viewed by 1181
Abstract
Composite collagen gels with hyaluronic acid are developed tissue-engineered structures for filling and regeneration of defects in various organs and tissues. For the first time, phytic acid was used to increase the stability and improve the mechanical properties of collagen gels with hyaluronic [...] Read more.
Composite collagen gels with hyaluronic acid are developed tissue-engineered structures for filling and regeneration of defects in various organs and tissues. For the first time, phytic acid was used to increase the stability and improve the mechanical properties of collagen gels with hyaluronic acid. Phytic acid is a promising cross-linker for collagen hydrogels and is a plant-derived antioxidant found in rich sources of beans, grains, and oilseeds. Phytic acid has several benefits due to its antioxidant, anticancer, and antitumor properties. In this work, studies were carried out on the kinetics of the self-assembly of collagen molecules in the presence of phytic and hyaluronic acids. It was shown that both of these acids do not lead to collagen self-assembly. Scanning electron microscopy showed that in the presence of phytic and hyaluronic acids, the collagen fibrils had a native structure, and the FTIR method confirmed the chemical cross-links between the collagen fibrils. DSC and rheological studies demonstrated that adding the phytic acid improved the stability and modulus of elasticity of the collagen gel. The presence of hyaluronic acid in the collagen gel slightly reduced the effect of phytic acid. The presence of phytic acid in the collagen gel improved the stability of the scaffold, but, after 1 week of cultivation, slightly reduced the viability of mesenchymal stromal cells cultured in the gel. The collagen type I gel with hyaluronic and phytic acids can be used to replace tissue defects, especially after the removal of cancerous tumors. Full article
(This article belongs to the Special Issue Physically Cross-Linked Gels and Their Applications)
Show Figures

Graphical abstract

13 pages, 7380 KiB  
Article
A Study on Enhanced Electrorheological Performance of Plate-like Materials via Percolation Gel-like Effect
by Suk Jekal, Minki Sa, Yeon-Ryong Chu, Chan-Gyo Kim, Jungchul Noh, Jiwon Kim, Ha-Yeong Kim, Won-Chun Oh, Zambaga Otgonbayar and Chang-Min Yoon
Gels 2023, 9(11), 891; https://doi.org/10.3390/gels9110891 - 10 Nov 2023
Viewed by 865
Abstract
The use of plate-like materials to induce a percolation gel-like effect in electrorheological (ER) fluids is sparsely documented. Hence, we dispersed plate-like materials, namely natural mica, synthetic mica, and glass, as well as their pulverized particles, in various concentrations in silicone oil to [...] Read more.
The use of plate-like materials to induce a percolation gel-like effect in electrorheological (ER) fluids is sparsely documented. Hence, we dispersed plate-like materials, namely natural mica, synthetic mica, and glass, as well as their pulverized particles, in various concentrations in silicone oil to form ER fluids. Subsequently, the rheological properties of the fluids were evaluated and compared to identify the threshold concentration for percolating a gel-like state. The shear stress and viscoelastic moduli under zero-field conditions confirmed that plate-like materials can be used to induce percolation gel-like effects in ER fluids. This is because of the high aspect ratio of the materials, which enhances their physical stability. In practical ER investigations, ER fluids based on synthetic mica (30.0 wt%) showed the highest yield stress of 516.2 Pa under an electric field strength of 3.0 kV mm−1. This was attributed to the formation of large-cluster networks and additional polarization induced by the ions. This study provides a practical approach for developing a new type of gel-like ER fluid. Full article
(This article belongs to the Special Issue Physically Cross-Linked Gels and Their Applications)
Show Figures

Graphical abstract

15 pages, 7086 KiB  
Article
Characterizing a Cost-Effective Hydrogel-Based Transparent Soil
by Kanghu Li, Lin Ma, Yang Gao, Jiyang Zhang and Sen Li
Gels 2023, 9(10), 835; https://doi.org/10.3390/gels9100835 - 21 Oct 2023
Viewed by 1195
Abstract
Transparent soil (TS) was specifically designed to support root growth in the presence of air, water, and nutrients and allowed the time-resolved phenotyping of roots in vivo. Nevertheless, it is imperative to further optimize the reagent cost of TS to enable its wider [...] Read more.
Transparent soil (TS) was specifically designed to support root growth in the presence of air, water, and nutrients and allowed the time-resolved phenotyping of roots in vivo. Nevertheless, it is imperative to further optimize the reagent cost of TS to enable its wider utilization. We substituted the costly Phytagel obtained from Sigma with two more economical alternatives, namely Biodee and Coolaber. TS beads from each brand were prepared using 12 different polymer concentrations and seven distinct crosslinker concentrations. A comprehensive assessment encompassing transparency, mechanical characteristics, particle size, porosity, and stability of TS was undertaken. Compared to the Sigma Phytagel brand, both Biodee and Coolaber significantly reduced the transparency and collapse stress of the TS they produced. Consequently, this led to a significant reduction in the allowable width and height of the growth box, although they could still simultaneously exceed 20 cm and 19 cm. There was no notable difference in porosity and stability among the TS samples prepared using the three Phytagel brands. Therefore, it is feasible to consider replacing the Phytagel brand to reduce TS production costs. This study quantified the differences in TS produced using three Phytagel brands at different prices that will better promote the application of TS to root phenotypes. Full article
(This article belongs to the Special Issue Physically Cross-Linked Gels and Their Applications)
Show Figures

Figure 1

16 pages, 4045 KiB  
Article
Poly(vinyl alcohol)/Pullulan Composite Hydrogels as a Potential Platform for Wound Dressing Applications
by Ioana-Alexandra Plugariu, Maria Bercea, Luiza Madalina Gradinaru, Daniela Rusu and Alexandra Lupu
Gels 2023, 9(7), 580; https://doi.org/10.3390/gels9070580 - 16 Jul 2023
Cited by 2 | Viewed by 1312
Abstract
Hydrogels are 3D networks with an excellent ability to retain a high amount of water or biological fluids, representing suitable candidates for wound dressing applications. They can provide a protective barrier and a moist environment, facilitating wound treatment. The present paper focuses on [...] Read more.
Hydrogels are 3D networks with an excellent ability to retain a high amount of water or biological fluids, representing suitable candidates for wound dressing applications. They can provide a protective barrier and a moist environment, facilitating wound treatment. The present paper focuses on physical hydrogels obtained from poly(vinyl alcohol) (PVA) and pullulan (PULL) mixtures in different weight ratios by using the freezing/thawing method. Hybrid hydrogels of similar polymer compositions were prepared in the presence of 0.5% Laponite® RD. The influence of polysaccharide and clay addition on the properties of PVA hydrogels was investigated. Scanning electron microscopy showed evidence of the inner porous structure. The viscoelastic properties were investigated in different shear conditions and revealed the influence of the hydrogel composition on the network strength. The swelling behavior was followed in physiological saline solutions at 37 °C and pH = 7.4. For all samples, a quasi-Fickian diffusion mechanism was found. The delivery of neomycin sulfate was studied in similar conditions as for the swelling tests (0.15 M NaCl solutions; 37 °C; pH = 7.4) and different kinetic models were used to determine the release mechanism. The Peppas–Sahlin approach described very well the in vitro drug release mechanism from the polymeric hydrogels in the absence of clay. However, the hybrid polymer/clay hydrogels showed the best fit with the Korsmeyer–Peppas model. According to the present study, the porous membranes containing 40–60% PULL (in absence of clay) are suitable for the release of therapeutic agents at wound sites in physiological conditions. Full article
(This article belongs to the Special Issue Physically Cross-Linked Gels and Their Applications)
Show Figures

Figure 1

22 pages, 5729 KiB  
Article
Alginate Hydrogel Formulation with Ketorolac for the Treatment of Pain Related Sialolithiasis
by Cristina Silva, Gladys Ramos-Yacasi, Mireia Mallandrich, Helena Colom-Codina, Joaquim Suñer-Carbó, Noelia Pérez-González, Ana Cristina Calpena and Francisco Fernández-Campos
Gels 2023, 9(5), 415; https://doi.org/10.3390/gels9050415 - 16 May 2023
Cited by 1 | Viewed by 1100
Abstract
Sialolithiasis mainly affects the oral salivary glands due to the presence of small stones that obstruct the secretion of saliva. The treatment and control of pain and inflammation during the course of this pathology is essential to guarantee the patient’s comfort. For this [...] Read more.
Sialolithiasis mainly affects the oral salivary glands due to the presence of small stones that obstruct the secretion of saliva. The treatment and control of pain and inflammation during the course of this pathology is essential to guarantee the patient’s comfort. For this reason, a ketorolac calcium cross-linked alginate hydrogel was developed, and it was then applied in the area of the buccal cavity. The formulation was characterized (swelling and degradation profile, extrusion, extensibility, surface morphology, viscosity, and drug release). The drug release was studied ex vivo in static Franz cells and with a dynamic ex vivo method under artificial saliva continuous flow. The product exhibits adequate physicochemical properties considering the intended purpose, and the drug concentrations retained in the mucosa were high enough to deliver a therapeutic local concentration able to reduce the pain associated with the patient’s conditions. The results confirmed the suitability of the formulation for application in the mouth. Full article
(This article belongs to the Special Issue Physically Cross-Linked Gels and Their Applications)
Show Figures

Figure 1

14 pages, 2684 KiB  
Article
Biodegradable Hydrogels Based on Chitosan and Pectin for Cisplatin Delivery
by Regina R. Vildanova, Svetlana F. Petrova, Sergey V. Kolesov and Vitaliy V. Khutoryanskiy
Gels 2023, 9(4), 342; https://doi.org/10.3390/gels9040342 - 17 Apr 2023
Cited by 4 | Viewed by 1606
Abstract
Preparation of stable hydrogels using physically (electrostatically) interacting charge-complementary polyelectrolyte chains seems to be more attractive from a practical point of view than the use of organic crosslinking agents. In this work natural polyelectrolytes—chitosan and pectin—were used, due to their biocompatibility and biodegradability. [...] Read more.
Preparation of stable hydrogels using physically (electrostatically) interacting charge-complementary polyelectrolyte chains seems to be more attractive from a practical point of view than the use of organic crosslinking agents. In this work natural polyelectrolytes—chitosan and pectin—were used, due to their biocompatibility and biodegradability. The biodegradability of hydrogels is confirmed by experiments with hyaluronidase as an enzyme. It has been shown that the use of pectins with different molecular weights makes it possible to prepare hydrogels with different rheological characteristics and swelling kinetics. These polyelectrolyte hydrogels loaded with cytostatic cisplatin as a model drug provide an opportunity for its prolonged release, which is important for therapy. The drug release is regulated to a certain extent by the choice of hydrogel composition. The developed systems can potentially improve the effects of cancer treatment due to the prolonged release of cytostatic cisplatin. Full article
(This article belongs to the Special Issue Physically Cross-Linked Gels and Their Applications)
Show Figures

Figure 1

13 pages, 4509 KiB  
Article
Synthesis and Degradation Properties of Sericin/PVA Hydrogels
by William Ekasurya, Joses Sebastian, Dita Puspitasari, Putri P. P. Asri and Lia A. T. W. Asri
Gels 2023, 9(2), 76; https://doi.org/10.3390/gels9020076 - 17 Jan 2023
Cited by 6 | Viewed by 2124
Abstract
One method of treating diabetic foot ulcers, mainly superficial and deep ulcers, is using a wound dressing in the form of a hydrogel. Sericin derived from silkworm cocoons is a promising hydrogel material candidate because it has anti-inflammatory properties and stimulates collagen production. [...] Read more.
One method of treating diabetic foot ulcers, mainly superficial and deep ulcers, is using a wound dressing in the form of a hydrogel. Sericin derived from silkworm cocoons is a promising hydrogel material candidate because it has anti-inflammatory properties and stimulates collagen production. Sericin was combined with PVA to increase the stability of the resulting hydrogel. Sericin/PVA hydrogel was prepared using the freeze–thawing method with variations in the solution concentration and volume ratio of PVA and sericin. Sericin was successfully extracted using an autoclave method. The FTIR results confirmed that sericin extracted from the cocoon had a dominant secondary structure in the form of a β-sheet. Hydrogel with a concentration of 4% with a 1:1 ratio of PVA and sericin showed good stability and resulted in a hydrogel with characteristics that combine PVA and sericin. The resulting hydrogel had an average pore size range of 24–191 µm and a porosity range of 70–85%, which meets the requirements for wound dressings. Through degradation testing in PBS solution, it was found that the sericin/PVA hydrogel experienced degradation of 60–75% after 672 h of testing. Full article
(This article belongs to the Special Issue Physically Cross-Linked Gels and Their Applications)
Show Figures

Graphical abstract

14 pages, 2124 KiB  
Article
Sodium Alginate-Quaternary Polymethacrylate Composites: Characterization of Dispersions and Calcium Ion Cross-Linked Gel Beads
by Wanwisa Khunawattanakul, Napaphak Jaipakdee, Thitiphorn Rongthong, Narin Chansri, Pathomthat Srisuk, Padungkwan Chitropas and Thaned Pongjanyakul
Gels 2022, 8(11), 739; https://doi.org/10.3390/gels8110739 - 15 Nov 2022
Cited by 3 | Viewed by 1248
Abstract
The objective of this work was to examine the effect of quaternary polymethacrylate (QPM), a water-insoluble polymer with a positive charge, on the characteristics of the sodium alginate (SA) dispersions and the calcium alginate (CA) gel beads containing propranolol HCl (PPN). The SA-QPM [...] Read more.
The objective of this work was to examine the effect of quaternary polymethacrylate (QPM), a water-insoluble polymer with a positive charge, on the characteristics of the sodium alginate (SA) dispersions and the calcium alginate (CA) gel beads containing propranolol HCl (PPN). The SA-QPM composite dispersions presented the formation of flocculates with a negative charge due to the electrostatic interaction of both substances. The QPM addition did not affect the SA dispersions’ Newtonian flow, but the composite dispersions’ viscosity enhancement was found. The PPN-loaded CA-QPM gel beads had more spherical than the PPN-loaded CA gel beads. The incorporation of QPM caused a bigger particle size, higher drug entrapment efficiency, and greater particle strength of the gel beads. Despite the similar water uptake property, the PPN-loaded CA-QPM gel beads displayed lower burst release and slower drug release rate than the PPN-loaded CA gel beads. However, the drug release from the PPN-loaded CA-QPM gel beads involved drug diffusion and matrix swelling mechanisms. This study demonstrated that adding QPM into the SA dispersions leads to a viscosity synergism. The CA-QPM gel beads display a good potential for use as a bioactive compound delivery system. Full article
(This article belongs to the Special Issue Physically Cross-Linked Gels and Their Applications)
Show Figures

Graphical abstract

Back to TopTop