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23 pages, 9496 KiB

Open AccessArticle

Metal Organic Framework-Incorporated Three-Dimensional (3D) Bio-Printable Hydrogels to Facilitate Bone Repair: Preparation and In Vitro Bioactivity Analysis

by Cho-E Choi, Aishik Chakraborty, Hailey Adzija, Yasmeen Shamiya, Khaled Hijazi, Ali Coyle, Amin Rizkalla, David W. Holdsworth and Arghya Paul

Gels 2023, 9(12), 923; https://doi.org/10.3390/gels9120923 - 23 Nov 2023

Viewed by 1397

Abstract

Hydrogels are three-dimensional (3D) water-swellable polymeric matrices that are used extensively in tissue engineering and drug delivery. Hydrogels can be conformed into any desirable shape using 3D bio-printing, making them suitable for personalized treatment. Among the different 3D bio-printing techniques, digital light processing [...] Read more.

Hydrogels are three-dimensional (3D) water-swellable polymeric matrices that are used extensively in tissue engineering and drug delivery. Hydrogels can be conformed into any desirable shape using 3D bio-printing, making them suitable for personalized treatment. Among the different 3D bio-printing techniques, digital light processing (DLP)-based printing offers the advantage of quickly fabricating high resolution structures, reducing the chances of cell damage during the printing process. Here, we have used DLP to 3D bio-print biocompatible gelatin methacrylate (GelMA) scaffolds intended for bone repair. GelMA is biocompatible, biodegradable, has integrin binding motifs that promote cell adhesion, and can be crosslinked easily to form hydrogels. However, GelMA on its own is incapable of promoting bone repair and must be supplemented with pharmaceutical molecules or growth factors, which can be toxic or expensive. To overcome this limitation, we introduced zinc-based metal-organic framework (MOF) nanoparticles into GelMA that can promote osteogenic differentiation, providing safer and more affordable alternatives to traditional methods. Incorporation of this nanoparticle into GelMA hydrogel has demonstrated significant improvement across multiple aspects, including bio-printability, and favorable mechanical properties (showing a significant increase in the compressive modulus from 52.14 ± 19.42 kPa to 128.13 ± 19.46 kPa with the addition of ZIF-8 nanoparticles). The designed nanocomposite hydrogels can also sustain drug (vancomycin) release (maximum 87.52 ± 1.6% cumulative amount) and exhibit a remarkable ability to differentiate human adipose-derived mesenchymal stem cells toward the osteogenic lineage. Furthermore, the formulated MOF-integrated nanocomposite hydrogel offers the unique capability to coat metallic implants intended for bone healing. Overall, the remarkable printability and coating ability displayed by the nanocomposite hydrogel presents itself as a promising candidate for drug delivery, cell delivery and bone tissue engineering applications. Full article

(This article belongs to the Special Issue Advances in Responsive Hydrogels)

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26 pages, 8003 KiB

Open AccessArticle

Adsorption of Safranin O Dye by Alginate/Pomegranate Peels Beads: Kinetic, Isotherm and Thermodynamic Studies

by Amina Abbaz, Sihem Arris, Gianluca Viscusi, Asma Ayat, Halima Aissaoui and Yasser Boumezough

Gels 2023, 9(11), 916; https://doi.org/10.3390/gels9110916 - 18 Nov 2023

Cited by 2 | Viewed by 1461

Abstract

Water pollution is regarded as a dangerous problem that needs to be resolved right away. This is largely due to the positive correlation between the increase in global population and waste production, especially food waste. Hydrogel beads based on sodium alginate (Alg) and [...] Read more.

Water pollution is regarded as a dangerous problem that needs to be resolved right away. This is largely due to the positive correlation between the increase in global population and waste production, especially food waste. Hydrogel beads based on sodium alginate (Alg) and pomegranate fruit peels (PP) were developed for the adsorption of Safranin O dye (SO) in aqueous solutions. The obtained Alg−PP beads were widely characterized. The effects of the contact time (0–180 min), initial concentration (10–300 mg/L), initial pH (2–10), adsorbent dosage (1–40 g/L) and the temperature (293–333 K) were investigated through batch tests. The data proved that the adsorption kinetics of SO reached equilibrium within 30 min and up to 180 min. The dye adsorption is concentration dependent while a slight effect of pH was observed. The adsorption data of SO onto synthesized beads follow the pseudo second-order model. The experimental data fitted very well to Langmuir model with correlation factor of 0.92 which demonstrated the favourable nature of adsorption. The maximum adsorption capacity of Alg−PP could reach 30.769 mg/g at 293 K. Calculation of Gibbs free energy and enthalpy indicated that adsorption of SO onto Alg−PP is spontaneous (negative ΔG) and endothermic (ΔH = 9.30 kJ/mol). Analysis of diffusion and mass transport phenomena were presented. The removal efficiency was found to be 88% at the first cycle and decreased to 71% at the end of the seventh cycle. The reported results revealed that the Alg−PP beads could be used as a novel natural adsorbent for the removal of high concentrated solutions of Safranin O which is a cationic dye from liquid affluents and as future perspective, it can be used to remove various pollutants from wastewater. Full article

(This article belongs to the Special Issue Advances in Responsive Hydrogels)

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19 pages, 6916 KiB

Open AccessArticle

Thermo-Responsive Sol-Gel-Based Nano-Carriers Containing Terbinafine HCl: Formulation, In Vitro and Ex Vivo Characterization, and Antifungal Activity

by Maryam Bajwa, Naila Tabassam, Huma Hameed, Ali Irfan, Muhammad Zaman, Mahtab Ahmad Khan, Gamal A. Shazly, Tooba Mehboob, Tehseen Riaz and Yousef A. Bin Jardan

Gels 2023, 9(10), 830; https://doi.org/10.3390/gels9100830 - 20 Oct 2023

Cited by 4 | Viewed by 1007

Abstract

The current research aims to create a sol-gel-based nanocarrier containing terbinafine formulated for transdermal delivery of the drug into the skin. Sol-gel-based nanocarriers were prepared via the cold method using poloxamer-188, poloxamer-407, and distilled water. The prepared formulation was examined for pH, gelation [...] Read more.

The current research aims to create a sol-gel-based nanocarrier containing terbinafine formulated for transdermal delivery of the drug into the skin. Sol-gel-based nanocarriers were prepared via the cold method using poloxamer-188, poloxamer-407, and distilled water. The prepared formulation was examined for pH, gelation temperature, Fourier transform infrared spectrophotometer (FTIR) analysis, thermal stability analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), particle size analysis, zeta potential, and anti-microbial activity. The in-vitro drug release study of F1 was found to be 94%, which showed greater drug release as compared to F2 and F3. The pH of the formulation was found to be within the range applicable to the skin. The gelation temperature was detected at 28 °C. The SEM images of formulations have spotted various particles well-segregated from each other. Analysis of formulations showed a mean globule size diameter of 428 nm, zeta potential values of 0.04 mV, refractive index (1.329), and viscosity (5.94 cP). FTIR analysis confirmed various functional groups’ presence in the prepared formulation. Thermal analysis has confirmed the stability of the drug within the prepared formulation. The growth of inhibition was found to be 79.2% in 60 min, which revealed that the prepared formulation has shown good permeation from the membrane. Hence, the sol-gel-based nanocarrier formulation of terbinafine was successfully developed and evaluated. Full article

(This article belongs to the Special Issue Advances in Responsive Hydrogels)

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13 pages, 4651 KiB

Open AccessArticle

Mechanically Tunable Hydrogels with Self-Healing and Shape Memory Capabilities from Thermo-Responsive Amino Acid-Derived Vinyl Polymers

by Shin-nosuke Nishimura, Dan Sato and Tomoyuki Koga

Gels 2023, 9(10), 829; https://doi.org/10.3390/gels9100829 - 19 Oct 2023

Cited by 2 | Viewed by 1142

Abstract

In this study, we report the fabrication and characterization of self-healing and shape-memorable hydrogels, the mechanical properties of which can be tuned via post-polymerization crosslinking. These hydrogels were constructed from a thermo-responsive poly(N-acryloyl glycinamide) (NAGAm) copolymer containing N-acryloyl serine methyl [...] Read more.

In this study, we report the fabrication and characterization of self-healing and shape-memorable hydrogels, the mechanical properties of which can be tuned via post-polymerization crosslinking. These hydrogels were constructed from a thermo-responsive poly(N-acryloyl glycinamide) (NAGAm) copolymer containing N-acryloyl serine methyl ester (NASMe) units (5 mol%) that were readily synthesized via conventional radical copolymerization. This transparent and free-standing hydrogel is produced via multiple hydrogen bonds between PNAGAm chains by simply dissolving the polymer in water at a high temperature (~90 °C) and then cooling it. This hydrogel exhibited moldability and self-healing properties. The post-polymerization crosslinking of the amino acid-derived vinyl copolymer network with glutaraldehyde, which acts as a crosslinker between the hydroxy groups of the NASMe units, tuned mechanical properties such as viscoelasticity and tensile strength. The optimal crosslinker concentration efficiently improved the viscoelasticity. Moreover, these hydrogels exhibited shape fixation (~60%)/memory (~100%) behavior owing to the reversible thermo-responsiveness (upper critical solution temperature-type) of the PNAGAm units. Our multifunctional hydrogel, with moldable, self-healing, mechanical tunability via post-polymerization crosslinking, and shape-memorable properties, has considerable potential for applications in engineering and biomedical materials. Full article

(This article belongs to the Special Issue Advances in Responsive Hydrogels)

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20 pages, 5023 KiB

Open AccessArticle

Lamotrigine-Loaded Poloxamer-Based Thermo-Responsive Sol–Gel: Formulation, In Vitro Assessment, Ex Vivo Permeation, and Toxicology Study

by Maria Riaz, Muhammad Zaman, Huma Hameed, Hafiz Shoaib Sarwar, Mahtab Ahmad Khan, Ali Irfan, Gamal A. Shazly, Ana Cláudia Paiva-Santos and Yousef A. Bin Jardan

Gels 2023, 9(10), 817; https://doi.org/10.3390/gels9100817 - 14 Oct 2023

Cited by 3 | Viewed by 1192

Abstract

The present study aimed to prepare, characterize, and evaluate a thermo-responsive sol–gel for intranasal delivery of lamotrigine (LTG), which was designed for sustained drug delivery to treat epilepsy. LTG sol–gel was prepared using the cold method by changing the concentrations of poloxamer 407 [...] Read more.

The present study aimed to prepare, characterize, and evaluate a thermo-responsive sol–gel for intranasal delivery of lamotrigine (LTG), which was designed for sustained drug delivery to treat epilepsy. LTG sol–gel was prepared using the cold method by changing the concentrations of poloxamer 407 and poloxamer 188, which were used as thermo-reversible polymers. The optimized formulations of sol–gel were analyzed for clarity, pH, viscosity, gelation temperature, gelation time, spreadability, drug content, in vitro drug release studies, ex vivo permeation studies, and in vivo toxicological studies. FTIR, XRD, and DSC were performed to determine the thermal stability of the drug and polymers. The prepared formulations had a clear appearance in sol form; they were liquid at room temperature and became gel at temperatures between 31 °C and 36 °C. The pH was within the range of the nasal pH, between 6.2 and 6.4. The drug content was found to be between 92% and 94%. In vitro drug release studies indicated that the formulations released up to 92% of the drug within 24 h. The FTIR, DSC, and XRD analyses showed no interaction between the drug and the polymer. A short-term stability study indicated that the formulation was stable at room temperature and at 4–8 °C. There was a slight increase in viscosity at room temperature, which may be due to the evaporation of the vehicle. A histological study indicated that there were no signs of toxicity seen in vital organs, such as the brain, kidney, liver, heart, and spleen. It can be concluded from the above results that the prepared intranasal sol–gel for the delivery of LTG is safe for direct nose-to-brain delivery to overcome the first-pass effect and thus enhance bioavailability. It can be considered an effective alternative to conventional drug delivery for the treatment of epilepsy. Full article

(This article belongs to the Special Issue Advances in Responsive Hydrogels)

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16 pages, 6596 KiB

Open AccessArticle

Study on Bioresponsive Gelatin-Hyaluronic Acid-Genipin Hydrogel for High Cell-Density 3D Bioprinting

by Mst Rita Khatun, Amitava Bhattacharyya, Maral Gunbayar, Minsik Jung and Insup Noh

Gels 2023, 9(8), 601; https://doi.org/10.3390/gels9080601 - 26 Jul 2023

Cited by 1 | Viewed by 1610

Abstract

The Development of bioresponsive extrudable hydrogels for 3D bioprinting is imperative to address the growing demand for scaffold design as well as efficient and reliable methods of tissue engineering and regenerative medicine. This study proposed genipin (5 mg) cross-linked gelatin (1 to 1.5 [...] Read more.

The Development of bioresponsive extrudable hydrogels for 3D bioprinting is imperative to address the growing demand for scaffold design as well as efficient and reliable methods of tissue engineering and regenerative medicine. This study proposed genipin (5 mg) cross-linked gelatin (1 to 1.5 g)-hyaluronic acid (0.3 g) hydrogel bioink (20 mL) tailored for 3D bioprinting. The focus is on high cell loading and a less artificial extra-cellular matrix (ECM) effect, as well as exploring their potential applications in tissue engineering. The bioresponsiveness of these hydrogel scaffolds was successfully evaluated at 37 °C and room temperature (at pH 2.5, 7.4, and 9). The rheological and mechanical properties (more than three times) increased with the increase in gelatin content in the hydrogel; however, the hydrogel with the least amount of gelatin showed the best extrusion capability. This optimized hydrogel’s high extrusion ability and post-printing shape fidelity were evident from 3D and four-axis printing of complex structures such as hollow tubes, stars, pyramids, and zigzag porous tubular (four-axis) scaffolds (printed at 90 kPa pressure, 70 mm/s speed, 22G needle, fourth axis rotation of 4 rpm). 3 million/mL MC3T3-E1 mouse osteoblast cells were used in preparing 3D bioprinted samples. The in vitro cell culture studies have been carried out in a CO₂ incubator (at 37 °C, 5% CO₂). In the cytocompatibility study, almost three times more cell viability was observed in 3 days compared to day 1 control, proving the non-toxicity and cell-supportiveness of these hydrogels. High cell viability and cell-to-cell interactions observed at the end of day 3 using this moderately stable hydrogel in 3D bioprinting exhibit high potential for precise cell delivery modes in tissue engineering as well as regenerative medicine. Full article

(This article belongs to the Special Issue Advances in Responsive Hydrogels)

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14 pages, 8800 KiB

Open AccessArticle

Gamma Radiation-Induced Advanced 2,3-Dimethylacrylic Acid-(2-Acrylamido-2-methyl-1-propanesulfonic Acid) Superabsorbent Hydrogel: Synthesis and Characterization

by Md Murshed Bhuyan and Jae-Ho Jeong

Gels 2023, 9(5), 426; https://doi.org/10.3390/gels9050426 - 19 May 2023

Cited by 2 | Viewed by 1292

Abstract

Gamma radiation technique for the preparation of pure hydrogels is gaining popularity worldwide. Superabsorbent hydrogels play vital roles in different fields of application. The present work mainly focuses on the preparation and characterization of 2,3-Dimethylacrylic acid-(2-Acrylamido-2-methyl-1-propane sulfonic acid) (DMAA–AMPSA) superabsorbent hydrogel by applying [...] Read more.

Gamma radiation technique for the preparation of pure hydrogels is gaining popularity worldwide. Superabsorbent hydrogels play vital roles in different fields of application. The present work mainly focuses on the preparation and characterization of 2,3-Dimethylacrylic acid-(2-Acrylamido-2-methyl-1-propane sulfonic acid) (DMAA–AMPSA) superabsorbent hydrogel by applying gamma radiation and optimization of the proper dose. To prepare DMAA–AMPSA hydrogel, different doses ranging from 2 kGy to 30 kGy were imparted on the blend aqueous solution of the monomers. The equilibrium swelling increases with increasing radiation dose, followed by decreasing after reaching a certain level, and the highest result is found to be 26,324.9% at 10 kGy. Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy confirmed the formation of co-polymer by showing the characteristic functional groups and proton environment of the gel. X-ray Diffraction (XRD) pattern indicates the crystalline/amorphous nature of the gel. The Differential Scanning Calorimetry (DSC) and Thermogravimetry Analysis (TGA) revealed the thermal stability of the gel. The surface morphology and constitutional elements were analyzed and confirmed by Scanning Electron Microscopy (SEM) equipped with Energy Dispersive Spectroscopy (EDS). Finally, it can be stated that hydrogels can be usable in metal adsorption, drug delivery, and other relevant fields. Full article

(This article belongs to the Special Issue Advances in Responsive Hydrogels)

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17 pages, 9869 KiB

Open AccessArticle

Synthesis of NVCL-NIPAM Hydrogels Using PEGDMA as a Chemical Crosslinker for Controlled Swelling Behaviours in Potential Shapeshifting Applications

by Billy Shu Hieng Tie, Elaine Halligan, Shuo Zhuo, Gavin Keane and Luke Geever

Gels 2023, 9(3), 248; https://doi.org/10.3390/gels9030248 - 20 Mar 2023

Cited by 2 | Viewed by 1448

Abstract

Stimuli-responsive hydrogels have recently gained interest within shapeshifting applications due to their capabilities to expand in water and their altering swelling properties when triggered by stimuli, such as pH and heat. While conventional hydrogels lose their mechanical strength during swelling, most shapeshifting applications [...] Read more.

Stimuli-responsive hydrogels have recently gained interest within shapeshifting applications due to their capabilities to expand in water and their altering swelling properties when triggered by stimuli, such as pH and heat. While conventional hydrogels lose their mechanical strength during swelling, most shapeshifting applications require materials to have mechanical strength within a satisfactory range to perform specified tasks. Thus, stronger hydrogels are needed for shapeshifting applications. Poly (N-isopropylacrylamide) (PNIPAm) and poly (N-vinyl caprolactam) (PNVCL) are the most popular thermosensitive hydrogels studied. Their close-to-physiological lower critical solution temperature (LCST) makes them superior candidates in biomedicine. In this study, copolymers made of NVCL and NIPAm and chemically crosslinked using poly (ethylene glycol) dimethacrylate (PEGDMA) were fabricated. Successful polymerisation was proven via Fourier transform infrared spectroscopy (FTIR). The effects of incorporating comonomer and crosslinker on the LCST were found minimal using cloud-point measurements, ultraviolet (UV) spectroscopy, and differential scanning calorimetry (DSC). Formulations that completed three cycles of thermo-reversing pulsatile swelling are demonstrated. Lastly, rheological analysis validated the mechanical strength of PNVCL, which was improved due to the incorporation of NIPAm and PEGDMA. This study showcases potential smart thermosensitive NVCL-based copolymers that can be applied in the biomedical shapeshifting area. Full article

(This article belongs to the Special Issue Advances in Responsive Hydrogels)

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17 pages, 3693 KiB

Open AccessArticle

Study on the Interaction of Plasma-Polymerized Hydrogel Coatings with Aqueous Solutions of Different pH

by Monique Levien, Zahra Nasri, Klaus-Dieter Weltmann and Katja Fricke

Gels 2023, 9(3), 237; https://doi.org/10.3390/gels9030237 - 17 Mar 2023

Cited by 2 | Viewed by 1105

Abstract

Amphiphilic hydrogels from mixtures of 2-hydroxyethyl methacrylate and 2-(diethylamino)ethyl methacrylate p(HEMA-co-DEAEMA) with specific pH sensitivity and hydrophilic/hydrophobic structures were designed and polymerized via plasma polymerization. The behavior of plasma-polymerized (pp) hydrogels containing different ratios of pH-sensitive DEAEMA segments was investigated concerning possible applications [...] Read more.

Amphiphilic hydrogels from mixtures of 2-hydroxyethyl methacrylate and 2-(diethylamino)ethyl methacrylate p(HEMA-co-DEAEMA) with specific pH sensitivity and hydrophilic/hydrophobic structures were designed and polymerized via plasma polymerization. The behavior of plasma-polymerized (pp) hydrogels containing different ratios of pH-sensitive DEAEMA segments was investigated concerning possible applications in bioanalytics. In this regard, the morphological changes, permeability, and stability of the hydrogels immersed in solutions of different pHs were studied. The physico-chemical properties of the pp hydrogel coatings were analyzed using X-ray photoelectron spectroscopy, surface free energy measurements, and atomic force microscopy. Wettability measurements showed an increased hydrophilicity of the pp hydrogels when stored in acidic buffers and a slightly hydrophobic behavior after immersion in alkaline solutions, indicating a pH-dependent behavior. Furthermore, the pp (p(HEMA-co-DEAEMA) (ppHD) hydrogels were deposited on gold electrodes and studied electrochemically to investigate the pH sensitivity of the hydrogels. The hydrogel coatings with a higher ratio of DEAEMA segments showed excellent pH responsiveness at the studied pHs (pH 4, 7, and 10), demonstrating the importance of the DEAEMA ratio in the functionality of pp hydrogel films. Due to their stability and pH-responsive properties, pp (p(HEMA-co-DEAEMA) hydrogels are conceivable candidates for functional and immobilization layers for biosensors. Full article

(This article belongs to the Special Issue Advances in Responsive Hydrogels)

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Review

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16 pages, 4164 KiB

Open AccessReview

Probing the Molecular Mechanism of Viscoelastic Relaxation in Transient Networks

by Shota Michida, Ung-il Chung and Takuya Katashima

Gels 2023, 9(12), 945; https://doi.org/10.3390/gels9120945 - 01 Dec 2023

Cited by 1 | Viewed by 919

Abstract

Hydrogels, which have polymer networks through supramolecular and reversible interactions, exhibit various mechanical responsibilities to its surroundings. The influence of the reversible bonds on a hydrogel’s macroscopic properties, such as viscoelasticity and dynamics, is not fully understood, preventing further innovative material development. To [...] Read more.

Hydrogels, which have polymer networks through supramolecular and reversible interactions, exhibit various mechanical responsibilities to its surroundings. The influence of the reversible bonds on a hydrogel’s macroscopic properties, such as viscoelasticity and dynamics, is not fully understood, preventing further innovative material development. To understand the relationships between the mechanical properties and molecular structures, it is required to clarify the molecular understanding of the networks solely crosslinked by reversible interactions, termed “transient networks”. This review introduces our recent progress on the studies on the molecular mechanism of viscoelasticity in transient networks using multiple methods and model materials. Based on the combination of the viscoelasticity and diffusion measurements, the viscoelastic relaxation of transient networks does not undergo the diffusion of polymers, which is not explained by the framework of conventional molecular models for the viscoelasticity of polymers. Then, we show the results of the comparison between the viscoelastic relaxation and binding dynamics of reversible bonds. Viscoelastic relaxation is primarily affected by “dissociation dynamics of the bonds” and “network structures”. These results are explained in the framework that the backbone, which is composed of essential chains supporting the stress, is broken by multiple dissociation events. This understanding of molecular dynamics in viscoelasticity will provide the foundation for designing transient networks. Full article

(This article belongs to the Special Issue Advances in Responsive Hydrogels)

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