Hydrophilic Hydrogel Research Articles

Evaluation of hydrophilic hydrogel prepared using Cissus quadrangularis in enhancing osseointegration of dental implants‐ a preliminary research in rabbits

Evaluation of hydrophilic hydrogel prepared using Cissus quadrangularis in enhancing osseointegration of dental implants‐ a preliminary research in rabbits

Enabling polyketone membrane with underwater superoleophobicity via a hydrogel-based modification for high-efficiency oil-in-water emulsion separation

Membrane separation is regarded as an efficient technology in treating oily wastewater. However, the oil fouling of the membrane is an unavoidable issue during the separation process, which will largely reduce the permeation flux or even destruct membrane structure. While polyketone is a promising membrane material with favorable chemical resistance to be implemented in oil/water separation, its weak hydrophilicity and underwater oleophobicity limit the possibility of high-efficiency separation. In this work, a hydrophilic alginate hydrogel was successfully deposited onto the polyketone membrane through a facile electrostatic attraction force strategy. By optimizing the concentration of the alginate hydrogel, stable underwater superoleophobicity and ultralow oil adhesion of the membrane were obtained. The membrane showed the significantly improved separation efficiency for the rejection of various kinds of oil-in-water emulsions, indicating the effectiveness and durability of the method proposed in this work. It is expected that this modification method may also be applied for the improvement of other membrane materials.

Preparation, characterization, and drug release study of ibuprofen-loaded poly (vinyl alcohol)/poly (vinyl pyrrolidone) bilayer antibacterial membrane

Controlling wound pain, absorption of wound exudate, and minimizing the frequency of changing the dressing are necessary parameters to facilitate wound-healing process. Hence, stable hydrophilic hydrogels applied in the form of film with the capability of wound exudate absorption and anti-inflammatory drug release may be used as an ideal wound dressing. Furthermore, physically crosslinked hydrogels are preferred over chemical ones because of being free from remaining harmful chemicals and adverse effects on the entrapped drugs. Thus, in this study, we developed an antibacterial bilayer membrane composed of a combination of polyvinyl alcohol/polyvinyl pyrrolidone (PVA/PVP) with the ability to release Ibuprofen (IBP). First, 1% IBP was incorporated in different ratios of PVA/PVP solution (90:10, 80:20, and 70:30); then, the hydrogels were crosslinked through repetitive freeze-thawing cycles followed by lyophilization, as the bottom layer. Second, the top layer was made in the same way but without the drug. Morphology, mechanical properties, swelling ratio, degradation rate, water vapor transmission rate (WVTR), and in vitro drug release of bilayer membranes were evaluated, then the content of PVP was optimized. The results indicated that the sample with the PVA/PVP ratio of 80:20 encompassed large and interconnected pores and also a proper swelling degree (500% in 48 h), weight loss (60% during 12 days) and WVTR (2721.1 ± 93.3 g/m2); thus, it is considered as the optimized membrane. MTT and antibacterial assays also showed acceptable viability and bactericidal activity for the membranes containing IBP. In conclusion, the prepared bilayer membrane can absorb wound exudate within the dressing matrix, release IBP locally, and keep its stability at the wound site. The bilayer membrane also exhibited an excellent antibacterial feature for accelerating the wound-healing process.

Boosting the cyclic stability and supercapacitive performance of graphene hydrogels via excessive nitrogen doping: Experimental and DFT insights

Nitrogen-doped mesoporous graphene hydrogel (MGHG) enjoys many unique characteristics for use as an efficient energy storage electrode material. Herein, a green one-pot hydrothermal synthesis strategy was employed to synthesize highly hydrophilic nitrogen-doped mesoporous graphene hydrogel. The morphological, structural, and compositional analyses were performed using FESEM, XRD, and XPS techniques. The as-prepared MGHG exhibits high wettability (contact angle = 58.9o), high surface area (318.226 m2/g), and an unprecedented nitrogen doping content of 2.95%. The fabricated MGHG was evaluated as a supercapacitor material in 1 M aqueous K2SO4 electrolyte, revealing a maximum specific capacitance of 595.7 F.g−1 with a low equivalent series resistance (0.1664 Ω) that is ascribed to the high porosity, high surface area, and the available nitrogen redox active sites. To further elucidate the electrochemical performance of MGHG, a symmetric supercapacitor device was assembled using MGHM as negative and positive electrodes. The fabricated device shows a maximum specific energy of 30 Wh kg−1 corresponding to a specific power 1000 W kg−1. The density functional theory (DFT) computations were utilized to better understand the high performance of the assembled devices. These superior results demonstrate the excellent performance of MGHG as a potential material for highly-performing supercapacitor devices with a potential window of 2.2 V.

Monolithic macroporous hydrogels prepared from oil-in-water high internal phase emulsions for high-efficiency purification of Enterovirus 71

Monolithic macroporous hydrogels was prepared from oil-in-water high internal phase emulsions (HIPEs) and heparinized using polydopamine (PDA) and polyethyleneimine (PEI) as mediators, and then used as a support of affinity chromatography to purify Enterovirus 71 (EV71) from culture supernatant. Our innovative strategy was characterized by two remits. (1) Interconnected macropores (1–5 μm) and high porosity (76–93%) of hydrophilic hydrogels ensured an excellent permeability (6.95 × 10−13 m2); (2) PDA/PEI composite provided abundant amino groups to immobilize heparin on macroporous hydrogels and increased the amount of carboxyl group to 46.5 μmol per column. A selective recognition of EV71 was achieved by receptor-ligand interaction between heparin and EV71. The adsorption capacity for EV71 was 986.0 ng per column and the recovery for EV71 reached a maximum of 79.9%. It was verified that these high performances were ascribed to the high density of heparin immobilized via PDA and PEI as mediators. Our innovative strategy provided a useful paradigm as a preparation method for heparin-affinity chromatographic medium for virus purification.

Tuning the sensitivity of fluoroionophore-based K+ sensors via variation of polymer matrix: A comparative study

Optical sensors were prepared via immobilization of K+ fluoroionophore (K+FI) into different hydrophilic polymers and their properties (luminescence brightness, stability, sensitivity, cross talk to sodium, dynamic range, response time) were investigated. Depending on the character of the used polymeric matrix, the fluorescence quantum yields for the K+-fluoroionophore complex (500 mM K+) span from 44 % in commercial polyurethane hydrogel D1 to 18 % in poly(2-hydroxyethyl methacrylate). Dynamic intensity measurements show reversibility of the sensors and response times (t90) below 1 min for most of the materials. Blending of poly(2-hydroxyethyl methacrylate) with polyurethane hydrogels is necessary to ensure compatibility of the indicator and the matrix. Comparison of dissociation constants (Kd) reveals moderate sensitivity enhancement in more hydrophilic polyurethane hydrogel D1 (Kd 51.8 mM) and much stronger enhancement in poly(2-hydroxyethyl methacrylate) (Kd 15.4 mM) compared to previously used hydrogel D4 (Kd 60.4 mM). Drastic increase in the sensitivity upon addition of negatively-charged aliphatic sulfonates is observed (Kd < 3 mM). In case of the latter, the enhancement in the sensitivity is significantly lower in presence of sodium ions. Modification of a commercially available polyurethane hydrogel with sulfonate groups enables preparation of stable sensors with improved binding ability (Kd 11.1 mM). This study demonstrates the fundamental role of the polymer matrix in characteristics of the solid-state optical potassium sensors and provides the guidelines for general design of ion sensors with improved characteristics.

Monitoring graphene oxide’s efficiency for removing Re(VII) and Cr(VI) with fluorescent silica hydrogels

Supported carbon quantum dots (CQDs), used as fluorescent sensors for the detection of metal ions, have rarely been used to remove heavy metals from water. Nitrogen-doped CQDs immobilized in hydrophilic silica hydrogels exhibited a more superior sensitivity and selectivity for the detection of Re(VII) and Cr(VI) than other metal ions, including Fe(III), Fe(II), Zn(II), Cu(II) and Mn(II). For the first time, low limits of detection (LOD) of 2.3 μM for Re(VII) detection and 65 nM for Cr(VI) detection were reported by a facile method. Based on the high selectivity of fluorescent silica hydrogels for Re(VII) and Cr(VI) detection, the removal of Re(VII) and Cr(VI) by graphene oxide (GO) in water was monitored with the hydrogels used as a turn-off fluorescent sensing platform. The consistent results of the sorption isotherms of each metal on GO, which were obtained from the fluorescence spectra and by UV absorption, further verified the possibility of monitoring metal removal by fluorescence detection. Remarkably, GO removed 1186 mg/g of Re(VII) but only 178 mg/g of Cr(VI). The density functional theory (DFT) calculations indicated that both Re(VII) and Cr(VI) formed stable bonds with silica hydrogels, confirming that the interactions between the metal ions and the substrate would promote the fluorescence quenching of the supported CQDs. On the other hand, Re(VII) interacted more strongly with the carboxyl groups of GO than Cr(VI). In addition, a real-time detection system was designed to alarm the service life of a GO filter used for Re(VII) removal.

Bioinspired programmable wettability arrays for droplets manipulation

The manipulation of liquid droplets demonstrates great importance in various areas from laboratory research to our daily life. Here, inspired by the unique microstructure of plant stomata, we present a surface with programmable wettability arrays for droplets manipulation. The substrate film of this surface is constructed by using a coaxial capillary microfluidics to emulsify and pack graphene oxide (GO) hybrid N-isopropylacrylamide (NIPAM) hydrogel solution into silica nanoparticles-dispersed ethoxylated trimethylolpropane triacrylate (ETPTA) phase. Because of the distribution of the silica nanoparticles on the ETPTA interface, the outer surface of the film could achieve favorable hydrophobic property under selective fluorosilane decoration. Owing to the outstanding photothermal energy transformation property of the GO, the encapsulated hydrophilic hydrogel arrays could shrink back into the holes to expose their hydrophobic surface with near-infrared (NIR) irradiation; this imparts the composite film with remotely switchable surface droplet adhesion status. Based on this phenomenon, we have demonstrated controllable droplet sliding on programmable wettability pathways, together with effective droplet transfer for printing with mask integration, which remains difficult to realize by existing techniques.

Structural reorganization and crack-healing properties of hydrogels based on dynamic diselenide linkages

ABSTRACT We report the dynamic behavior of diselenide-containing hydrophilic polyurethanes and hydrogels based on diselenide exchange reactions in an aqueous media. Diselenide-containing linear and cross-linked polyurethanes were synthesized via polyaddition reactions using diselenide-containing diol in combination with pyridinium diol that enhances the hydrophilicity of the polymer chains. The obtained linear polyurethanes underwent photo-induced diselenide exchange reactions with small diselenide compounds and degraded to smaller fragments, confirming the dynamicity of the obtained hydrophilic polyurethanes. The prepared hydrogels displayed characteristic large swelling behavior based on the structural reorganization through diselenide exchange either under photo-irradiation at 365 nm or even in the dark at room temperature. The diselenide-containing hydrogels also showed crack-healing behavior under the same exchanging conditions, presenting the utility of diselenide linkages as simple and useful units to offer high dynamicity to hydrogels.

Preparation and Performance Analysis of Ophthalmic Polymer Using SWCNT and SWCCNT

The purpose of this study is to fabricate an ophthalmic lens by copolymerizing two types of carbon nanotubes and hydrophilic hydrogel lens materials, and to investigate its application as an ophthalmic lens material by analyzing its physical properties and antimicrobial effect. For polymerization, HEMA (2-hydroxyethyl methacrylate), EGDMA (ethylene glycol dimethacrylate), a crosslinking agent, and AIBN (azobisisobutyronitrile), an initiator, are used as a basic combination, and a single-walled carbon nanotube and a single-walled, carboxylic-acid-functionalized carbon nanotube are used as additives. To analyze the physical properties, the water content, refractive index, breaking strength, and antimicrobial effect of the fabricated lenses are measured. The fabricated lenses satisfies all the basic properties of the basic hydrogel ophthalmic lens. The water content increases with increasing amount of additive and decreases with addition of 0.2% ratio of nanoparticles. The refractive index is inversely proportional to the water content result. As a result of the antimicrobial test of the fabricated lens, the addition of carbon nanotubes shows an excellent antimicrobial effect. Therefore, it is considered that the fabricated lens can be applied as a functional material for basic ophthalmic hydrogel lenses.

Biomimetic nanocomposite scaffolds based on surface modified PCL-nanofibers containing curcumin embedded in chitosan/gelatin for skin regeneration

Recently, nanofibrous-hydrogel composites are luring attention for tissue regeneration applications as they mimic soft-tissues' microstructure. Mostly, the electrospun nanofibers based on synthetic polymers such as Polycaprolactone (PCL) are placed in a crosslinked hydrogels. Due to hydrophobic nature of PCL, integration of these nanofibers with the hydrophilic hydrogels of matrix is not sufficient. In this study, we applied Poly(ethylene glycol) methyl ether methacrylate (PEGMA)-surface-modified PCL nanofibers within chitosan-gelatin hydrogels for skin regeneration applications. In addition, curcumin was loaded into PCL nanofibers due to its great impact on skin regeneration process. Fabricated nanofibrous-hydrogel scaffolds were characterized using scanning electron microscopy (SEM), porosimetery, Fourier transform infrared spectroscopy (FTIR), mechanical compression test, and water uptake studies. Curcumin release was investigated using UV/Vis spectrophotometry. In order to study biocompatibility of scaffolds MTT assay and cell culture was performed using L929 cells. FTIR spectra confirmed PEGMA modification of PCL nanofibers. Results of mechanical test determined that surface modified PCL nanofibers improved mechanical strength and modulus of scaffolds. Porosimetery studies showed proper porosity of scaffolds for skin regeneration from 90.43 to 71.48% and pore size of 101–256 μm. Biological test confirmed proper biocompatibility and good cell attachment to the scaffolds. Taken together, the chitosan/gelatin hydrogel incorporating PEGMA modified PCL nanofibers containing curcumin shows great potential for skin regeneration.

UV LED Curing of Hydrogel-Modified Textiles with High Anti-Fouling Resistance

The hydrogel grafted polyethylene terephthalate (PET) textiles were envisioned to have oil-repelling properties due to the synergistic of combining hydrophilic hydrogel onto PET textiles surfaces. In this work, PAAm hydrogels were grafted i.e. via immersion or dipping methods onto pristine (PPET) and alkaline treated (APET) PET textile surfaces using UV LED light source. The obtained samples were then characterized based on the degree of grafting (DG), Fourier transformed infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), surface wettability by contact angle and oil fouling test. APET was found to be more efficient for grafting compared to the PPET due to the surface modification made after the alkaline treatment. APET surface turned to be more hydrophilic than PPET due to the presence of hydroxyl group (-OH) as proven in the FTIR. In addition, the PAAm hydrogel was confirmed to be successfully grafted onto the APET textile via immersion or dipping methods with the optimum DG obtained was at 20 minutes of UV time. This finding has also proven the potential of UV LED as a promising technology to replace the conventional UVA for hydrogel curing. Higher DG was obtained for immersed grafting sample (PAAm-g-APETimm; DG=160 wt%) when compared to the dipped sample (PAAm-g-APETdip; DG=60 wt%) which indicates that higher mass fraction of PAAm could be attached to the surface of PAAm-g-APETimm. Apart from that, PAAm-g-APETimm shows lower water contact angle (WCA) with WCA=60.90° as compared to PAAm-g-APETdip with WCA=83.15° which could be due to higher thickness of hydrophilic layer that resulted in slower rate of oil fouling performance. To summarize, the PAAm hydrogel grafted onto PET textiles were significantly improved and possessed excellent surface towards oil staining performance. By comparing both textile modifications, grafting via dipping was more preferable. Even though the DG obtained was slightly lower, its thin layer of hydrogel grafted on the APET textile surface was sufficient to de-stain oil from the textile surface at a faster rate (~0.60-0.70 seconds). To some extent; the hydrogel modified textiles via UV LED curing has bright vision in the near future as promising tools for oil/water separation.

Hydrogel-Templated Transfer-Printing of Conductive Nanonetworks for Wearable Sensors on Topographic Flexible Substrates.

Transfer-printing enables the assembly of functional nanomaterials on unconventional substrates with a desired layout in a controllable manner. However, transfer-printing to substrates with complex surfaces remains a challenge. Herein, we show that hydrogels serve as effective template material platforms for the assembly and transfer-printing of conductive nanonetwork patterns for flexible sensors on various topographic surfaces in a very simple yet versatile manner. The non-adherence, nanoporous structure, and molding capability of the hydrophilic hydrogel enable the assembly of conductive nanonetwork patterns on the hydrogel surface and transfer of the nanonetworks onto various flexible and topographic substrates. Flexible strain sensors and pressure sensors that monitor finger motions and arterial pulses are successfully demonstrated using the hydrogel-templated approach. The rich chemistry of polymeric networks, facile molding capability, and biocompatibility of hydrogels could be further combined with additive technology for hydrogels and electronic materials for emerging four-dimensional functional materials and soft bioelectronics.

Ionic Liquid Hydrogel Composite Membranes (IL-HCMs)

In this work, novel hydrogel composites membranes comprising [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide as monomer, N,N-methylene bisacrylamide as cross-linker, and 1-butyl-3-methylimidazolium hexafluorophosphate as ionic liquid additive, have been developed. Ionic liquid hydrogel composite membranes (IL-HCMs) were tested for membrane contactors applications, aiming to reduce surface hydrophobicity of the polypropylene support, to reduce wetting tendency due to interaction with hydrophobic foulants, while affecting salts rejection in desalination operation, because of the entrapment of ILs inside the porous mesh-like structure of the gel layer. Transmembrane flux comparable to the sole polypropylene support was observed for IL content &gt; 1 wt.%. Furthermore, all IL membranes presented a larger rejection to sodium chloride than the PP support or the composites without ionic liquid inside. Although the overall transmembrane flux of IL-HCMs developed in this work is comparable with that of state of the art MD membranes, this study demonstrated that the strong hydrophilic hydrogel layer, with C.A. &lt; 50° for IL content larger than 1 wt.%, serves as a stabilization coating, by providing the new media between the feed and the hydrophobic membrane surface, thus potentially controlling the diffusion of hydrophobic foulant molecules. This would result in a decrease in the membrane wetting and fouling aptitude.

Biocidal Efficacy of a Hydrogen Peroxide Lens Care Solution Incorporating a Novel Wetting Agent.

To compare the antimicrobial effects of CLEAR CARE, a 3% hydrogen peroxide (H2O2) solution formulated for simultaneous cleaning, daily protein removal, disinfection, and storage of soft (hydrophilic) hydrogel, silicone hydrogel, and gas-permeable contact lenses, and CLEAR CARE PLUS, consisting of the 3% H2O2 solution plus a novel wetting agent, polyoxyethylene-polyoxybutylene (EOBO-21). Three lots each of the 2 solutions were incubated with 5 compendial microorganisms required by the Food and Drug Administration (FDA) 510(k) and International Organization for Standardization (ISO) 14729 stand-alone procedures, 4 clinical isolates of Gram-positive and Gram-negative bacteria, and trophozoites and cysts of 2 Acanthamoeba strains that are associated with microbial keratitis. Microbial loads were evaluated after disinfection and neutralization. Both solutions exceeded the FDA/ISO stand-alone primary criteria against Gram-positive and Gram-negative compendial bacteria, yeast, and mold after only 1.5-hr disinfection/neutralization. At the recommended minimum disinfection time, bacteria were reduced by 4.4 to 5.1 logs, yeast by 4.4 to 4.9 logs, and mold by 2.9 to 3.5 logs with and without organic soil. In addition, both solutions eliminated or effectively reduced populations of clinically relevant ocular bacterial isolates (4.5-5.0 logs), Acanthamoeba trophozoites (3.4-4.2 logs), and cysts (1.5-2.1 logs). Both solutions eliminated or reduced populations of FDA/ISO compendial bacteria and fungi as well as clinically relevant microorganisms and Acanthamoeba trophozoites and cysts. The addition of EOBO-21 to the 3% H2O2 lens care solution had no impact on antimicrobial activity.

Super Hydrophilic Semi-IPN Fluorescent Poly(N-(2-hydroxyethyl)acrylamide) Hydrogel for Ultrafast, Selective, and Long-Term Effective Mercury(II) Detection in a Bacteria-Laden System.

Convenient, low-cost chemosensors for hazardous mercury ion detection have been receiving more and more attention in recent studies. However, most of these practical studies are based on an ideal sterile detecting atmosphere and ignore the role of bacteria in actual Hg(II) analytes. Herein, we demonstrate a new type of hydrophilic semi-IPN fluorescent polyHEAA hydrogel chemosensors fabricated by UV polymerization in situ interpenetrating fluorescent polymer PA-NDBCB with a polyHEAA network. Because of specific intermolecular interaction, i.e., hydrogen bonding between hydrophilic fluorescent polymer and polyHEAA matrix comprising a distinct semi-IPN structure, the mechanical property of bulk fluorescent hydrogels can be greatly improved over that of pure polyHEAA hydrogels. Moreover, the design of the hydrogel chemosensors rely on the highly efficient cyclization reaction between Hg(II) ions and the thiourea moieties that induce a visible "green-to-blue" fluorescence color change. On account of the hydrophilic porous structures, these hydrogel chemosensors achieve ultrafast, sensitive, selective Hg(II) detection (detection limit of 0.067 μM) and enable facile ratiometric actual detection in real-world aqueous system. Notably, they maintain fluorescence emission and detection property even under long-term coculture in a complex E. coli bacteria-laden environment. This novel strategy could inspire future construction of soft interfaces/fluorescent apparatus for hazardous Hg(II) detection in a complex real-world system.

In Situ Synthesis of Silver Nanoparticles within Hydrogel-Conjugated Membrane for Enhanced Antibacterial Properties.

Biofouling negatively impacts water treatment performance of membranes by reducing water permeability, increasing energy consumption, and shortening the lifetime of the membranes. In this study, we integrated the bactericidal property of silver nanoparticles (AgNPs) with hydrophilicity of hydrogels to modify membranes that not only reduce adhesion, but also deactivate the adhered bacteria. Two approaches for AgNP synthesis were adopted-in situ synthesis and encapsulation in single step, and immobilization in multistep. Formation of AgNPs was confirmed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) studies. Compared to the pristine membrane, AgNP/hydrogel-modified membranes displayed no adverse effect in water flux under gravitational flow condition. The AgNP/hydrogel-modified membranes also exhibited better antibacterial properties (inhibition of adhesion and growth of Escherichia coli) as demonstrated by the bacterial growth, inhibition zone, and coculture (with the membranes) studies. The improvements could be attributed to the synergistic effect of hydrophilic hydrogel networks and the presence of bactericidal AgNPs. In addition, comparison of the antibacterial studies revealed the superiority of the encapsulated AgNPs over the immobilized AgNPs. This could be attributed to the efficient release of the former over the latter. To the best of our knowledge, this is the first study that demonstrates the enhancement of antibacterial properties of membrane via in situ synthesis and encapsulation of AgNPs within hydrogel matrices.

Dual pH‐ and thermal‐responsive nanocomposite hydrogels for controllable delivery of hydrophobic drug baicalein

AbstractHydrogels have been widely used as mild biomaterials due to their bio‐affinity, high drug loading capability and controllable release profiles. However, hydrogel‐based carriers are greatly limited for the delivery of hydrophobic payloads due to the lack of hydrophobic binding sites. Herein, nano‐liposome micelles were embedded in semi‐interpenetrating poly[(N‐isopropylacrylamide)‐co‐chitosan] (PNIPAAm‐co‐CS) and poly[(N‐isopropylacrylamide)‐co‐(sodium alginate)] (PNIPAAm‐co‐SA) hydrogels which were responsive to both temperature and pH, thereby establishing tunable nanocomposite hydrogel delivery systems. Nano‐micelles formed via the self‐assembly of phospholipid could serve as the link between hydrophobic drug and hydrophilic hydrogel due to their special amphiphilic structure. The results of transmission and scanning electron microscopies and infrared spectroscopy showed that the porous hydrogels were successfully fabricated and the liposomes encapsulated with baicalein could be well contained in the network. In addition, the experimental results of response release in vitro revealed that the smart hydrogels showed different degree of sensitiveness under different pH and temperature stimuli. The results of the study demonstrate that combining PNIPAAm‐co‐SA and PNIPAAm‐co‐CS hydrogels with liposomes encapsulated with hydrophobic drugs is a feasible method for hydrophobic drug delivery and have potential application prospects in the medical field. © 2018 Society of Chemical Industry

Tough hydrophilic polyurethane-based hydrogels with mechanical properties similar to human soft tissues

Biocompatible tough hydrogels are ideal for the fabrication of flexible medical devices such as prosthetics.

Sonochemically Synthesized Lignin Nanoparticles and its Application in the Development of Nanocomposite Hydrogel

Abstract The hydrophilic gels or hydrogels are chemically or physically crosslinked polymeric network which are capable in absorbing a large quantity of water in their three-dimensional polymeric network. In contrast with synthetic polymer hydrogels, biopolymeric hydrogels are biocompatible, flexible, biodegradable, and non-toxic, hence they have received a great attention in numerous biomedical, engineering, and industrial applications. Conventionally developed synthetic polymer [i.e., polyvinyl alcohol (PVA)] and biopolymer [i.e., chitosan (CS)] hydrogels have insignificant physical as well as chemical properties, which can be overcome by the development of these hydrogels in association with nanoparticles. The present study focuses on the synthesis of lignin nanoparticles derived from natural resources by using ultrasound and its application in the development of CS–PVA hydrogel. The nanoparticles were found to be in the range of 10–50 nm. Physical crosslinking method has been adopted for the development of hydrogel. Further to examine the thermal stability of hydrogel TGA was performed. Post addition of nanoparticles in CS–PVA hydrogel manifested a significant increase in the thermal stability. Considering numerous advantages of the proposed nanocomposite hydrogel, this could be possibly used in drug delivery, food packaging and wound dressing