Natural and synthetic materials based CMCh/PVA hydrogels for oxaliplatin delivery: Fabrication, characterization, In-Vitro and In-Vivo safety profiling

Multilayered hydrogel scaffold construct with native tissue matched elastic modulus: A regenerative microenvironment for urethral scar-free healing

The unsuitable deformation stimulus, harsh urine environment, and lack of a regenerative microenvironment (RME) prevent scaffold-based urethral repair and ultimately lead to irreversible urethral scarring. The researchers clarify the optimal elastic modulus of the urethral scaffolds for urethral repair and design a multilayered PVA hydrogel scaffold for urethral scar-free healing. The inner layer of the scaffold has self-healing properties, which ensures that the wound effectively resists harsh urine erosion, even when subjected to sutures. In addition, the scaffold's outer layer has an extracellular matrix-like structure that synergizes with adipose-derived stem cells to create a favorable RME. In vivo experiments confirm successful urethral scar-free healing using the PVA multilayered hydrogel scaffold. Further mechanistic study shows that the PVA multilayer hydrogel effectively resists the urine-induced inflammatory response and accelerates the transition of urethral wound healing to the proliferative phase by regulating macrophage polarization, thus providing favorable conditions for urethral scar-free healing. This study provides mechanical criteria for the fabrication of urethral tissue-engineered scaffolds, as well as important insights into their design.

Glucose detection: In-situ colorimetric analysis with double-layer hydrogel microneedle patch based on polyvinyl alcohol and carboxymethyl chitosan

Skin interstitial fluid (ISF) has emerged as a significant reservoir of biomarkers for disease diagnosis and prevention. Microneedle (MN) patches are regarded as an optimal platform for ISF extraction from the skin due to their non-invasive nature. However, challenges such as prolonged sampling durations and complex detection procedures impede timely metabolic analysis. In this investigation, we amalgamated MN technology with immobilized enzyme technology to fabricate a dual-layer MN patch integrating sampling and detection functionalities, thereby enabling in-situ colorimetric detection of hyperglycemia. The tip layer of the patch, comprising polyvinyl alcohol/carboxymethyl chitosan (PVA/CMCS) MN, was synthesized utilizing a chemical crosslinking approach for the first time, with glucose oxidase (GOx) being incorporated. The hydrophilicity of CMCS expedited the extraction process, facilitating the retrieval of approximately 10 mg of ISF within 10 min. The backing layer consisted of an immobilized polyvinyl alcohol-chitosan-horseradish peroxidase (PVA-CS-HRP) hydrogel film loaded with 3,3', 5,5'-tetramethylbenzidine (TMB). Incorporating macromolecular polymer PVA and CS for HRP immobilization addressed the issue of poor stability associated with traditional natural enzymes, thereby enhancing the sensitivity of the reaction system. The in-situ colorimetric sensor facilitated minimally invasive ISF extraction and swift conversion of glucose levels into detectable color changes.

Pharmaceutical chitosan hydrogels: A review on its design and applications

Chitosan (CS) has become a focal point of extensive research in the pharmaceutical industry due to its remarkable biodegradability, biocompatibility and sustainability. Chitosan hydrogels (CS HGs) are characterized by their viscoelasticity, flexibility and softness. The polar surfaces exhibit properties that mitigate interfacial tension between the hydrogel and body fluids. The inherent compatibility of CS HGs with body tissues and fluids positions them as outstanding polymers for delivering therapeutic proteins, peptides, DNA, siRNA, and vaccines. Designed to release drugs through mechanisms such as swelling-based diffusion, bioerosion, and responsiveness to stimuli, CS HGs offer a versatile platform for drug delivery. CS HGs play pivotal roles in serving purposes such as prolonging the duration of preprogrammed drug delivery, enabling stimuli-responsive smart delivery to target sites, protecting encapsulated drugs within the mesh network from adverse environments, and facilitating mucoadhesion and penetration through cell membranes. This review comprehensively outlines various novel preparation methods of CS HGs, delving into the parameters influencing drug delivery system design, providing a rationale for CS HG utilization in drug delivery, and presenting diverse applications across the pharmaceutical landscape. In synthesizing these facets, the review seeks to contribute to a nuanced understanding of the multifaceted role that CS HGs play in advancing drug delivery methodologies.

Melitoxin Inhibits Proliferation, Metastasis, and Invasion of Glioma U251 Cells by Down-regulating F2RL1

As the principal active component of bee venom, melittin has an anti-cancer effect in different cancers. This study was aimed to investigate the effect of melittin in glioma and explore whether F2RL1 is closely involved in glioblastoma cells proliferation. TCGA and GES databases were used to evaluate the role of F2RL1 in gliomas. The U251 cells were divided into a control lentivirus + PBS group (NC-PBS), F2RL1 intervention lentivirus + PBS group (KD-PBS), control lentivirus + melittin group (NC-melittin), and F2RL1 intervention lentivirus + melittin group (KD-melittin). Cell proliferation was detected by MTT and EDU staining assays. The apoptosis rate was assessed by flow cytometry. Expressions of genes related to apoptosis, cycle arrest, migration, and invasion were detected by qRT-PCR. Cellular LDH concentrations were detected by ELISA. The subcutaneous tumor volume of nude mice was analyzed by xenograft method. F2RL1 was significantly overexpressed in glioma tissues and were reduced in the melittin-treated group compared to the blank group. F2RL1 knockdown and melittin alone or in combination increased the proportion of cells in the G1-phase, and the combination was more pronounced. The KD-melittin group showed a decrease in the number of viable cells at 24, 48, 72, and 96 h compared to the NC-PBS group. The number of cell migration and invasion was decreased in the KD-melittin group compared to the other groups. Moreover, the genes related to cell cycle arrest and apoptosis were significantly changed in the KD-melittin group. At weeks 4, 5, and 6, the tumor volume in the KD-melittin group was smaller than that in the KD-PBS group and NC-melittin group. Interference with the target gene F2RL1 inhibited the proliferation of glioma U251 cells, and melittin treatment inhibited the proliferation of glioma U251 cells. Melittin inhibited the proliferation of glioma U251 cells by suppressing the expression of target gene F2RL1.

Injectable Chitosan-Methoxy Polyethylene Glycol Hybrid Hydrogel Untangling the Wound Healing Behavior: In Vitro and In Vivo Evaluation

Wound healing, particularly for difficult-to-treat wounds, presents a serious threat and may lead to complications. Currently available dressings lack mucoadhesion, safety, efficacy, and, most importantly, patient compliance. Herein, we developed a unique, simple, and inexpensive injectable chitosan-methoxy polyethylene glycol (chitosan-mPEG) hybrid hydrogel with tunable physicochemical and mechanical properties for wound healing. The detailed physicochemical and rheological characterization of the chitosan-mPEG hydrogel has revealed chemical interaction between available -NH2 groups of chitosan and -COOH groups of mPEG acid, which, to our perspective, enhanced the mechanical and wound healing properties of hybrid chitosan and mPEG hydrogel compared to solo chitosan or PEG hydrogel. By introducing mPEG, the wound healing ability of hydrogel is synergistically improved due to its antibacterial feature, together with chitosan's innate role in hemostasis and wound closure. The detailed hemostasis and wound closure potential of the chitosan-mPEG hydrogel were investigated in a rat model, which confirmed a significant acceleration in wound healing and ultimately wound closure. In conclusion, the developed chitosan-mPEG hydrogel met all the required specifications and could be developed as a promising material for hemostasis, especially wound management, and as an excellent candidate for wound healing application.

Carboxymethyl chitosan/polyvinyl alcohol double network hydrogels prepared by freeze-thawing and calcium chloride cross-linking for efficient dye adsorption

The discharge of dye wastewater resulting from rapid industrial development has become a serious environmental concern. Therefore, there is a pressing need to develop efficient methods and technologies for the removal of dye pollutants. This study introduced a double network hydrogel, with varying carboxymethyl chitosan (CMCS) contents and polyvinyl alcohol (PVA), employing a combination of freeze- thawing and calcium chloride cross-linking. The investigation focused on the rheological properties of the hydrogels and their removal ability of acidic blue 93 (AB). The results showed that the strength and viscoelastic modulus of composite hydrogels were positively correlated with the CMCS content, and all composite hydrogels exhibited the typical weak strain overshoot behavior. The pore size of the gel initially decreased and then increased, with the densest pores observed at 4 wt% CMCS, showing the optimal removal ability for AB. The adsorption process followed pseudo second-order kinetic model, dominated by external diffusion, and exhibited inhomogeneous multilayer adsorption. This study unveils the potential of CMCS/PVA gels as adsorbents, offering inspirations for the design and development of polyvinyl alcohol-based gels for applications in the food industry.

Water-Responsive 3D Electronics for Smart Biological Interfaces

Three-dimensional (3D) electronic systems with their potential for enhanced functionalities often require complex fabrication processes. This paper presents a water-based, stimuli-responsive approach for creating self-assembled 3D electronic systems, particularly suited for biorelated applications. We utilize laser scribing to programmatically shape a water-responsive bilayer, resulting in smart 3D electronic substrates. Control over the deformation direction, actuation time, and surface curvature of rolling structures is achieved by adjusting laser-scribing parameters, as validated through experiments and numerical simulations. Additionally, self-locking structures maintain the integrity of the 3D systems. This methodology enables the implementation of spiral twining electrodes for electrophysiological signal monitoring in plants. Furthermore, the integration of self-rolling electrodes onto peripheral nerves in a rodent model allows for stimulation and recording of in vivo neural activities with excellent biocompatibility. These innovations provide viable paths to next-generation 3D biointegrated electronic systems for life science studies and medical applications.

Development of Poly(sorbitol adipate)-g-poly(ethylene glycol) Mono Methyl Ether-Based Hydrogel Matrices for Model Drug Release

Hydrogels were prepared by Steglich esterification and by crosslinking pre-synthesized poly(sorbitol adipate)-graft-poly(ethylene glycol) mono methyl ether (PSA-g-mPEG) using different-chain-length-based disuccinyl PEG. PSA and PSA-g-mPEG were investigated for polymer degradation as a function of time at different temperatures. PSA-g-mPEG hydrogels were then evaluated for their most crucial properties of swelling that rendered them suitable for many pharmaceutical and biomedical applications. Hydrogels were also examined for their Sol-Gel content in order to investigate the degree of cross-linking. Physical structural parameters of the hydrogels were theoretically estimated using the modified Flory-Rehner theory to obtain approximate values of polymer volume fraction, the molecular weight between two crosslinks, and the mesh size of the hydrogels. X-ray diffraction was conducted to detect the presence or absence of crystalline regions in the hydrogels. PSA-g-mPEG hydrogels were then extensively examined for higher and lower molecular weight solute release through analysis by fluorescence spectroscopy. Finally, the cytotoxicity of the hydrogels was also investigated using a resazurin reduction assay. Experimental results show that PSA-g-mPEG provides an option as a biocompatible polymer to be used for pharmaceutical applications.

Platinum-based drugs and hydrogel: a promising anti-tumor combination

Platinum-based drugs are widely used as first-line anti-tumor chemotherapy agents. However, they also have nonnegligible side effects due to the free drugs in circulation. Therefore, it is necessary to develop efficient and safe delivery systems for better tumor cell targeting. Hydrogel is a promising anti-tumor drug carrier that can form a platinum/hydrogel combination system for drug release, which has shown better anti-tumor effects in some studies. However, there is a lack of systematic summary in this field. This review aims to provide a comprehensive overview of the platinum/hydrogel combination system with the following sections: firstly, an introduction of platinum-based drugs; secondly, an analysis of the platinum/hydrogel combination system; and thirdly, a discussion of the advantages of the hydrogel-based delivery system. We hope this review can offer some insights for the development of the platinum/hydrogel combination system for better cancer therapy.

Dual-network hydrogels based on dynamic imine and borate ester bonds with antibacterial and self-healing properties

Polymeric hydrogel materials with multiple functions are in great demand in practical biomedical scenarios. In this work, a self-healing hydrogel with both antimicrobial properties was prepared using a strategy that combines dynamic imine and borate ester bonds. In this hydrogel, polyvinyl alcohol (PVA) is used as the base network, and borax solution as the cross-linking agent, and borate ester bonds can be formed between these two. Dialdehyde carboxymethyl cellulose (DCMC) was selected to cross-link with the amino groups in carboxymethyl chitosan (CMCS) and polyethyleneimine (PEI) to form dynamic imine bonds. The PVA/PEI/DCMC/CMCS hydrogels prepared by double chemical cross-linking have good mechanical properties (maximum tensile strength up to 289 KPa and strain at the break up to 1025%). Due to the uniqueness of the two chemical bonds, the hydrogel material is self-healing at room temperature without additional stimulation. In addition, the inherent antibacterial properties of the raw materials in this hydrogel confer antibacterial properties, with a kill rate of up to 99% against E. coli and S. aureus. The multifunctional hydrogels developed in this study provide more ideas and references for the future application of hydrogel materials in practical scenarios.

Carboxymethyl Chitosan Microgels for Sustained Delivery of Vancomycin and Long-Lasting Antibacterial Effects

Carboxymethyl chitosan (CMCh) is a unique polysaccharide with functional groups that can develop positive and negative charges due to the abundant numbers of amine and carboxylic acid groups. CMCh is widely used in different areas due to its excellent biocompatibility, biodegradability, water solubility, and chelating ability. CMCh microgels were synthesized in a microemulsion environment using divinyl sulfone (DVS) as a crosslinking agent. CMCh microgel with tailored size and zeta potential values were obtained in a single stem by crosslinking CMCh in a water-in-oil environment. The spherical microgel structure is confirmed by SEM analysis. The sizes of CMCh microgels varied from one micrometer to tens of micrometers. The isoelectric point of CMCh microgels was determined as pH 4.4. Biocompatibility of CMCh microgels was verified on L929 fibroblasts with 96.5 ± 1.5% cell viability at 1 mg/mL concentration. The drug-carrying abilities of CMCh microgels were evaluated by loading Vancomycin (Van) antibiotic as a model drug. Furthermore, the antibacterial activity efficiency of Van-loaded CMCh microgels (Van@CMCh) was investigated. The MIC values of the released drug from Van@CMCh microgels were found to be 68.6 and 7.95 µg/mL against E. coli and S. aureus, respectively, at 24 h contact time. Disk diffusion tests confirmed that Van@CMCh microgels, especially for Gram-positive (S. aureus) bacteria, revealed long-lasting inhibitory effects on bacteria growth up to 72 h.

Hyaluronic acid/alginate-based biomimetic hydrogel membranes for accelerated diabetic wound repair

The study aims to develop a new multifunctional biopolymer-based hydrogel membrane dressing by adopting a solvent casting method for the controlled release of cefotaxime sodium at the wound site. Sodium alginate enhances collagen production in the skin, which provides tensile strength to healing tissue. Moreover, the significance of extracellular molecules such as hyaluronic acid in the wound the healing cascade renders these biopolymers an essential ingredient for the fabrication of hydrogel membranes via physical crosslinking (hydrogen bonding). These membranes were further investigated in terms of their structure, and surface morphology, as well as cell viability analysis. A membrane with the most suitable characteristics was chosen as a candidate for cefotaxime sodium loading and in vivo analysis. Results show that the 3D porous nature of developed membranes allows optimum water vapor and oxygen transmission (>8.21 mg/mL) to divert excessive wound exudate away from the diabetic wound bed, MTT assay confirmed cell viability at more than 80%. In vivo results confirmed that the CTX-HA-Alg-PVA hydrogel group showed rapid wound healing with accelerated re-epithelization and a decreased inflammatory response. Conclusively, these findings indicate that CTX-HA-Alg-PVA hydrogel membranes exhibit a suitable niche for use as dressing membranes for healing of diabetic wounds.

A Novel Multifunctional Crosslinking PVA/CMCS Hydrogel Containing Cyclic Peptide Actinomycin X2 and PA@Fe with Excellent Antibacterial and Commendable Mechanical Properties

Bacterial infected environments and resulting bacterial infections have been threatening the human health globally. Due to increased bacterial resistance caused by improper and excessive use of antibiotics, antibacterial biomaterials are being developed as alternatives to antibiotics in some cases. Herein, an advanced multifunctional hydrogel with excellent antibacterial properties, enhanced mechanical properties, biocompatibility and self-healing performance, was designed through freezing-thawing method. This hydrogel network is composed of polyvinyl alcohol (PVA), carboxymethyl chitosan (CMCS), protocatechualdehyde (PA), ferric iron (Fe) and an antimicrobial cyclic peptide actinomycin X2 (Ac.X2). The double dynamic bonds among protocatechualdehyde (PA), ferric iron (Fe) and carboxymethyl chitosan containing coordinate bond (catechol-Fe) as well as dynamic Schiff base bonds and hydrogen bonds endowed the hydrogel with enhanced mechanical properties. Successful formation of hydrogel was confirmed through ATR-IR and XRD, and structural evaluation through SEM analysis, whereas mechanical properties were tested with electromechanical universal testing machine. The resulting PVA/CMCS/Ac.X2/PA@Fe (PCXPA) hydrogel has favorable biocompatibility and excellent broad-spectrum antimicrobial activity against both S. aureus (95.3 %) and E. coli (90.2 %) compared with free-soluble Ac.X2, which exhibited subpar performance against E. coli reported in our previous studies. This work provides a new insight on preparing multifunctional hydrogels containing antimicrobial peptides as antibacterial material.

Development and evaluation of bioinspired pH-responsive sericin-chitosan-based hydrogel for controlled colonic delivery of PETase: Harnessing PETase-triggered degradation of microplastics

The gravity of threats posed by microplastic pollution to the environment cannot be overestimated. Being ubiquitous in the living environment, microplastics reach humans through the food chain causing various hazardous effects. Microplastics can be effectively degraded by PETase enzymes. The current study reports, for the first time, a hydrogel-encapsulated, bioinspired colonic delivery of PETase. A free radical polymerization-assisted hydrogel system was synthesized from sericin, chitosan, and acrylic acid using N,N'-methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. The hydrogel was characterized with FTIR, PXRD, SEM, and thermal analysis to confirm the development of a stabilized hydrogel system. The hydrogel showed 61 % encapsulation efficiency, maximum swelling, and cumulative PETase release (96 %) at pH 7.4. The mechanism of PETase release exhibited the Higuchi pattern of release with an anomalous transport mechanism. SDS-PAGE analysis confirmed the preservation of the post-release structural integrity of PETase. The released PETase exhibited concentration- and time-dependent degradation of polyethylene terephthalate in vitro. The developed hydrogel system exhibited the intended features of a stimulus-sensitive carrier system that can be efficiently used for the colonic delivery of PETase.

Polymeric Nanogel for Oral Delivery of the Chemotherapeutic Agent: Fabrication and Evaluation Alongside Toxicological Studies and Histopathological Examination

Nanogel has attracted considerable attention as one of the most versatile drug delivery systems, especially for site-specific and/or time-controlled delivery of the chemotherapeutic agent. The main objective of this study was to prepare the polymeric nanogel characterized by Fourier transform infrared spectroscopy, x-ray diffraction, thermogravimetric analysis, differential scanning, and oral acute toxicity. Free radical polymerization was done for the fabrication of polymeric nanogel. Fourier transform infrared spectroscopy was used to confirm the successful free radical polymerization. Various techniques such as x-ray diffraction, differential scanning calorimetric, and thermogravimetric analysis measurement were used to investigate the thermal behavior and crystallinity of developed nanogel. Parameters such as swelling, drug loading, and in vitro drug release is enhanced as polymers and monomers concentrations increase while these parameters decrease in case of increasing crosslinker concentration. The oral biocompatibility results of developed nanogel exhibited no toxicity in rabbits. Histopathological changes were observed between empty and loaded group. The nanosized gel offers a specific surface area which increases the stability of loaded drug (oxaliplatin) and bioavailability of the drug (oxaliplatin) as compared to the conventional drug delivery systems.

Mucoadhesive Polymers and Their Applications in Drug Delivery Systems for the Treatment of Bladder Cancer

Bladder cancer (BC) is the tenth most common type of cancer worldwide, affecting up to four times more men than women. Depending on the stage of the tumor, different therapy protocols are applied. Non-muscle-invasive cancer englobes around 70% of the cases and is usually treated using the transurethral resection of bladder tumor (TURBIT) followed by the instillation of chemotherapy or immunotherapy. However, due to bladder anatomy and physiology, current intravesical therapies present limitations concerning permeation and time of residence. Furthermore, they require several frequent catheter insertions with a reduced interval between doses, which is highly demotivating for the patient. This scenario has encouraged several pieces of research focusing on the development of drug delivery systems (DDS) to improve drug time residence, permeation capacity, and target release. In this review, the current situation of BC is described concerning the disease and available treatments, followed by a report on the main DDS developed in the past few years, focusing on those based on mucoadhesive polymers as a strategy. A brief review of methods to evaluate mucoadhesion properties is also presented; lastly, different polymers suitable for this application are discussed.

Designing and In Vitro Characterization of pH-Sensitive Aspartic Acid-Graft-Poly(Acrylic Acid) Hydrogels as Controlled Drug Carriers

Acetaminophen is an odorless and white crystalline powder drug, used in the management of fever, pain, and headache. The half-life of acetaminophen is very short; thus, multiple intakes of acetaminophen are needed in a day to maintain a constant pharmacological action for an extended period of time. Certain severe adverse effects are produced due to the frequent intake of acetaminophen, especially hepatotoxicity and skin rashes. Therefore, a drug carrier system is needed which not only prolongs the release of acetaminophen, but also enhances the patient compliance. Therefore, the authors prepared novel aspartic acid-graft-poly(acrylic acid) hydrogels for the controlled release of acetaminophen. The novelty of the prepared hydrogels is based on the incorporation of pH-sensitive monomer acrylic acid with polymer aspartic acid in the presence of ethylene glycol dimethacrylate. Due to the pH-sensitive nature, the release of acetaminophen was prolonged for an extended period of time by the developed hydrogels. Hence, a series of studies was carried out for the formulated hydrogels including sol-gel fraction, FTIR, dynamic swelling, polymer volume analysis, thermal analysis, percent porosity, SEM, in vitro drug release studies, and PXRD analysis. FTIR analysis confirmed the grafting of acrylic acid onto the backbone of aspartic acid and revealed the development of hydrogels. The thermal studies revealed the high thermal stability of the fabricated hydrogels as compared to pure aspartic acid. An irregular surface with a few pores was indicated by SEM. PXRD revealed the amorphous state of the developed hydrogels and confirmed the reduction in the crystallinity of the unreacted aspartic acid by the formulated hydrogels. An increase in gel fraction was observed with the increasing concentration of aspartic acid, acrylic acid, and ethylene glycol dimethacrylate due to the availability of a high amount of free radicals. The porosity study was influenced by the various compositions of developed hydrogels. Porosity was increased due to the enhancement in the concentrations of aspartic acid and acrylic acid, whereas it decreased with the increase in ethylene glycol dimethacrylate concentration. Similarly, the pH-responsive properties of hydrogels were evaluated by dynamic swelling and in vitro drug release studies at two different pH levels (1.2 and 7.4), and a greater dynamic swelling and acetaminophen release were exhibited at pH 7.4 as compared to pH 1.2. An increase in swelling, drug loading, and drug release was seen with the increased incorporation of aspartic acid and acrylic acid, whereas a decrease was detected with the increase in the concentration of ethylene glycol dimethacrylate. Conclusively, the formulated aspartic acid-based hydrogels could be employed as a suitable nonactive pharmaceutical ingredient for the controlled delivery of acetaminophen.

Polyvinyl alcohol/carboxymethyl chitosan hydrogel loaded with silver nanoparticles exhibited antibacterial and self-healing properties

Hydrogel materials are gradually increasing research in biological aspects due to their unique properties. In order to prepare hydrogels with the potential to be used in clinical wound therapy, the authors prepared a bifunctional hydrogel with antibacterial and self-healing properties. The hydrogel was composed of borax cross-linked polyvinyl alcohol (PVA) and carboxymethyl chitosan (CMCS), which realizes self-healing between polymers through hydrogen bonds and borate ester bonds. The double cross-linking of hydrogen bonds and borate ester bonds also endows the hydrogel with better mechanical properties (toughness and tensile stress can reach 22.30 MJ/m³ and 70.35 KPa, respectively). On this basis, adding highly stable silver nanoparticles (AgNPs) to the hydrogel can effectively inhibit the growth of E. coli and S. aureus. This idea provides the possibility for the application of hydrogels in the process of biological wound healing.

Development, characterization and In-vitro evaluation of guar gum based new polymeric matrices for controlled delivery using metformin HCl as model drug

Currently, hydrogels are considered as ideal biomaterials due to their unique structure and characteristics that facilitates considerable hydrophilicity, swelling, drug loading and release. In this study, we report pH-responsive GG-MAA-AMPS hydrogel delivery system prepared via free radical polymerization technique. Hydrogels were loaded with Metformin HCl as a model drug. Hydrogels were characterized through Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). FTIR confirmed the successful crosslinking of reactants, hydrogel network formation and drug loading. TGA and DSC proved the higher thermal stability of reactants after crosslinking and drug loading. XRD analysis showed decrease in crystallinity of drug after loading into the hydrogels. SEM revealed smooth and glassy appearance of both loaded and unloaded hydrogels. Gel content was increased with increase in concentration of reactants. Drug entrapment was decreased by increasing concentration of GG and AMPS while MAA acted inversely. Hydrogels displayed pH-dependent swelling and drug release behavior being high at pH 6.8 and 7.4 while low at acidic pH (1.2). Oral tolerability in rabbits showed that hydrogels were safe without causing any hematological or histopathological changes in healthy rabbits. Based on the obtained results, GG-MAA-AMPS can be considered as potential carrier for metformin HCl as well as other hydrophilic drugs.

Bioactive and multifunctional keratin-pullulan based hydrogel membranes facilitate re-epithelization in diabetic model

Hydrogel membrane dressings with multifunctional tunable properties encompassing biocompatibility, anti-bacterial, oxygen permeability, and adequate mechanical strength are highly preferred for wound healing. The present study aimed to develop biopolymer-based hydrogel membranes for the controlled release of therapeutic agent at the wound site. Toward this end we developed Cefotaxime sodium (CTX) loaded keratin (KR)-pullulan (PL) based hydrogel membrane dressings. All membranes show optimized vapor transmission rate (≥1000 g/ m²/day), oxygen permeability >8.2 mg/mL, MTT confirmed good biocompatibility and sufficient tensile strength (17.53 ± 1.9) for being used as a wound dressing. Nonetheless, KR-PL-PVA membranes show controlled CTX release due to enriched hydrophilic moieties which protect the wound from getting infected. In vivo results depict that CTX-KR-PL-PVA membrane group shows a rapid wound closure rate (p < 0.05) with appreciable angiogenesis, accelerated re-epithelization, and excessive collagen deposition at the wound site. These results endorsed that CTX-KR-PL-PVA hydrogel membranes are potential candidates for being used as dressing material in the diabetic wound.

Self-crosslinked chitosan/κ-carrageenan-based biomimetic membranes to combat diabetic burn wound infections

Diabetic wound infection often leads to compromised healing with frequent chances of sepsis, amputation and even death. Traditional patient care emphasized on early debridement and fluid resuscitation followed by intravenous antibiotics therapy. However, compromised vasculature often limit the systemic effect of antibiotics. Current study focused formulation of chitosan HCl, κ- carrageenan and PVA based physical cross-linked hydrogel membrane dressings loaded with cefotaxime sodium (CTX), for potential diabetic burn wound healing by adopting solvent casting method. Results of mechanical strength shows tensile strength and % elongation of 12.63 ± 0.25 and 48 ±3.05 respectively. Water vapor transmission rate (WVTR) depicts that despite of formulation KCP3 and KCP6, all hydrogel membranes have WVTR value in range of ideal dressing i.e., 2000-2500 g/m2/day. Whereas, all hydrogel membranes have oxygen permibility values more than 8.2 mg/ml. Bacterial penetration analysis confirms the barrier property of formulated membranes. Drug loaded hydrogel membrane showed control release up to 24 hr which provide protection against bacterial proliferation. Present study aims to constructs diabetic burn rat model which demonstrate that CTX loaded hydrogel membrane shown significantly rapid wound closure higher re-epithelization and numerous granulation tissue formation as compared to positive and negative control group. Conclusively, it is confirmed that formulated hydrogel membranes are beneficial and can be considered as a promising membrane dressing to treat diabetic burn wound.

Synthesis and In Vitro Evaluation of Aspartic Acid Based Microgels for Sustained Drug Delivery

The main focus of the current study was to sustain the releasing behavior of theophylline by fabricated polymeric microgels. The free radical polymerization technique was used for the development of aspartic acid-co-poly(2-acrylamido-2-methylpropanesulfonic acid) microgels while using various combinations of aspartic acid, 2-acrylamido-2-methylpropanesulfonic acid, and N′,N′-methylene bisacrylamide as a polymer, monomer, and cross-linker, respectively. Ammonium peroxodisulfate and sodium hydrogen sulfite were used as initiators. Characterizations such as DSC, TGA, SEM, FTIR, and PXRD were performed for the fabricated microgels to assess their thermal stability with unreacted polymer and monomer, their surface morphology, the formation of a new polymeric system of microgels by evaluating the cross-linking of functional groups of the microgels’ contents, and to analyze the reduction in crystallinity of the theophylline by fabricated microgels. Various studies such as dynamic swelling, drug loading, sol–gel analysis, in vitro drug release studies, and kinetic modeling were carried out for the developed microgels. Both dynamic swelling and percent drug release were found higher at pH 7.4 as compared to pH 1.2 due to the deprotonation of functional groups of aspartic acid and AMPS. Similarly, sol–gel analysis was performed and an increase in gel fraction was observed with the increasing concentration of microgel contents, while sol fraction was decreased. Conclusively, the prepared carrier system has the potential to sustain the release of the theophylline for an extended period of time.

Enhancement of dispersion stability of inorganic additives via poly(sodium-4-styrenesulfonate) treatment geared to hydrogel applications

This study reports the preparation of poly(sodium-4-styrene sulfonate) (PSS) treated bentonite and clinoptilolite to prevent the agglomeration and sedimentation of these inorganic fillers during the preparation of hydrogel. For this purpose PSS treated fillers were prepared by using various techniques (dip and dry, hydrothermal, one-step ball milling and ultrasonication methods). The most suitable technique for preparing these PSS treated inorganic fillers (abbreviated as BP-dip and CP-dip) was the dip and dry method. BP-dip and CP-dip based polyvinyl alcohol/polyvinylpyrrolidone (PVA/PVP) composite hydrogels were prepared using the freeze/thawing method after the addition of one of BP-dip and CP-dip inorganic fillers in various amounts. The swelling properties, stability behaviors and Rhodamine B (RhB) adsorption of the composite hydrogels were studied. It was found that the swelling degrees of CP-dip and BP-dip based composite hydrogels with 25 mg of filler were higher than that of all other samples. The kinetic mechanism of RhB adsorption process and the related characteristic kinetic parameters were investigated by Pseudo kinetic models. The adsorption kinetics results for RhB adsorption were found best fitted with pseudo-second-order kinetics model. The maximum RhB adsorption capacity was determined to be for PVA/PVP-CP-dip25, which was 3.3 times higher than that of the unfilled PVA/PVP hydrogel.

β-cyclodextrin chitosan-based hydrogels with tunable pH-responsive properties for controlled release of acyclovir: design, characterization, safety, and pharmacokinetic evaluation

In this work, series of pH-responsive hydrogels (FMA1-FMA9) were synthesized, characterized, and evaluated as potential carrier for oral delivery of an antiviral drug, acyclovir (ACV). Different proportions of β-cyclodextrin (β-CD), chitosan (CS), methacrylic acid (MAA) and N' N'-methylenebis-acrylamide (MBA) were used to fabricate hydrogels via free radical polymerization technique. Fourier transform infrared spectroscopy confirmed fabrication of new polymeric network, with successful incorporation of ACV. Scanning electron microscopy (SEM) indicated presence of slightly porous structure. Thermal analysis indicated enhanced thermal stability of polymeric network. Swelling studies were carried out at 37 °C in simulated gastric and intestinal fluids. The drug release data was found best fit to zero-order kinetics. The preliminary investigation of developed hydrogels showed a pH-dependent swelling behavior and drug release pattern. Acute oral toxicity study indicated no significant changes in behavioral, clinical, or histopathological parameters of Wistar rats. Pharmacokinetic study indicated that developed hydrogels caused a significant increase in oral bioavailability of ACV in rabbit plasma as compared to oral suspension when both were administered at a single oral dose of 20 mg kg-1 bodyweight. Hence, developed hydrogel formulation could be used as potential candidate for controlled drug delivery of an antiviral drug acyclovir.

Formulation and In-Vitro Characterization of pH-Responsive Semi-Interpenetrating Polymer Network Hydrogels for Controlled Release of Ketorolac Tromethamine

Ketorolac tromethamine is a non-steroidal anti-inflammatory drug used in the management of severe pain. The half-life of Ketorolac tromethamine is within the range of 2.5–4 h. Hence, repeated doses of Ketorolac tromethamine are needed in a day to maintain the therapeutic level. However, taking several doses of Ketorolac tromethamine in a day generates certain complications, such as acute renal failure and gastrointestinal ulceration. Therefore, a polymeric-controlled drug delivery system is needed that could prolong the release of Ketorolac tromethamine. Therefore, in the current study, pH-responsive carbopol 934/sodium polystyrene sulfonate-co-poly(acrylic acid) (CP/SpScPAA) hydrogels were developed by the free radical polymerization technique for the controlled release of Ketorolac tromethamine. Monomer acrylic acid was crosslinked with the polymers carbopol 934 and sodium polystyrene sulfonate by the cross-linker N’,N’-methylene bisacrylamide. Various studies were conducted to evaluate and assess the various parameters of the fabricated hydrogels. The compatibility of the constituents used in the preparation of hydrogels was confirmed by FTIR analysis, whereas the thermal stability of the unreacted polymers and developed hydrogels was analyzed by TGA and DSC, respectively. A smooth and porous surface was indicated by SEM. The crystallinity of carbopol 934, sodium polystyrene sulfonate, and the prepared hydrogels was evaluated by PXRD, which revealed a reduction in the crystallinity of reactants for the developed hydrogels. The pH sensitivity of the polymeric hydrogel networks was confirmed by dynamic swelling and in vitro release studies with two different pH media i.e., pH 1.2 and 7.4, respectively. Maximum swelling was exhibited at pH 7.4 compared to pH 1.2 and, likewise, a greater percent drug release was perceived at pH 7.4. Conclusively, we can demonstrate that the developed pH-sensitive hydrogel network could be employed as a suitable carrier for the controlled delivery of Ketorolac tromethamine.

Doxorubicin-Loaded Gold Nanoarchitectures as a Therapeutic Strategy against Diffuse Intrinsic Pontine Glioma

Diffuse Intrinsic Pontine Gliomas (DIPGs) are highly aggressive paediatric brain tumours. Currently, irradiation is the only standard treatment, but is palliative in nature and most patients die within 12 months of diagnosis. Novel therapeutic approaches are urgently needed for the treatment of this devastating disease. We have developed non-persistent gold nano-architectures (NAs) functionalised with human serum albumin (HSA) for the delivery of doxorubicin. Doxorubicin has been previously reported to be cytotoxic in DIPG cells. In this study, we have preclinically evaluated the cytotoxic efficacy of doxorubicin delivered through gold nanoarchitectures (NAs-HSA-Dox). We found that DIPG neurospheres were equally sensitive to doxorubicin and doxorubicin-loaded NAs. Colony formation assays demonstrated greater potency of NAs-HSA-Dox on colony formation compared to doxorubicin. Western blot analysis indicated increased apoptotic markers cleaved Parp, cleaved caspase 3 and phosphorylated H2AX in NAs-HSA-Dox treated DIPG neurospheres. Live cell content and confocal imaging demonstrated significantly higher uptake of NAs-HSA-Dox into DIPG neurospheres compared to doxorubicin alone. Despite the potency of the NAs in vitro, treatment of an orthotopic model of DIPG showed no antitumour effect. This disparate outcome may be due to the integrity of the blood-brain barrier and highlights the need to develop therapies to enhance penetration of drugs into DIPG.

Polyvinyl alcohol based-drug delivery systems for cancer treatment

Polyvinyl alcohol (PVA) is a biodegradable semicrystalline synthetic polymer that has been used for biomedical applications for several years. In the pharmaceutical area, PVA has been widely used to prepare solid dispersions to improve the solubility of drugs. Furthermore, it has been demonstrated that PVA is highly biocompatible and non-toxic in in-vitro and in-vivo studies. Several reports provided in this review suggest a promising strategy for cancer treatment. Thus far, the current therapy includes a combination of surgery, chemotherapy, and radiotherapy, the effectivity can be limited due to the heterogeneous manifestations of the disease, dose-related toxicity, and side effects. A promising strategy is the implementation of a targeted therapy using hydrogels, microparticles, or nanoparticles (NPs), capable of encapsulating, protecting, transporting, and targeted administration of a therapeutic agent. Considering the relevance of the PVA in conjunction with their copolymers, it has become a promising biodegradable material to build novel functional composites used in the fabrication of hydrogels, microparticles, nanoparticles, and nanocomposites for drug delivery systems in cancer treatment.

Synthesis, Characterization and Safety Evaluation of Sericin-Based Hydrogels for Controlled Delivery of Acyclovir

Conventional formulations of antiviral drug acyclovir have various limitations such as low bioavailability. The current study was aimed at developing polymeric matrices for the controlled delivery of acyclovir using sericin as polymer and acrylic acid (AA) as a monomer. The free radical polymerization technique was used for hydrogel formulation. Briefly, sericin was chemically cross-linked with acrylic acid. N′-N′-methylene bis-acrylamide (MBA) and ammonium persulfate (APS) were used as cross-linker and initiator, respectively. FTIR spectra showed that acyclovir was successfully loaded into sericin hydrogel. SEM micrographs revealed that the outer surface was solid-like and smooth. According to DSC thermograms, the developed polymeric network was thermally stable. Amorphous nature of acyclovir was observed in XRD. The pH of medium and reactants’ concentration affected swelling dynamics and acyclovir release pattern. In addition, drug release occurred through a diffusion-controlled process. Sericin hydrogel suspension was well tolerable up to 3800 mg/kg of rabbits’ body weight. Haematology and serum chemistry results were well within the range signifying normal liver and kidney functions. Similarly, histopathology slides of the rabbit’s vital organs were also in normal condition without causing any histopathological change. It was concluded from the findings that sericin-co-AA polymeric matrices are ideal for the pH-dependent delivery of acyclovir.

Natural proteins and polysaccharides in the development of micro/nano delivery systems for the treatment of inflammatory bowel disease

Treatments for inflammatory bowel disease (IBD) are typically immunosuppressive. Despite a range of treatment options, limited efficacy, systemic toxicities like bone marrow suppression, infections and malignancy are their serious setbacks. There exists an unmet medical need for novel therapeutic agents without safety concerns resulting from chronic, systemic immunosuppression. Of late, several natural agents with better therapeutic potential have been reported. It is very likely that restricting the release of the active molecules to the intestine would further improve their clinical efficacy and safety. To this end, novel polymer-based micro/nano formulations protect the drug from gastric environment and slowly release the drug in the colon. However, cost and side-effects associated to synthetic polymers have led to the development of biocompatible, economic and pharmaceutically well-accepted biomacromolecules in exploring their potential in IBD. Since last few years, biological proteins, polysaccharides and their combinations have shown great efficacy in colitis induced animal models. In this review, micro/nano formulations developed using biomacromolecules like chitosan, zein, pectin, casein, alginate, dextran, glucomannan and hyaluronic acid have been reviewed focusing on their potential in protecting active cargo, avoiding premature release, distal colon targeting along with their impact on reshaping the altered gut microbiota and how it can ameliorate the colitis conditions.

Novel versatile 3D bio-scaffold made of natural biocompatible hagfish exudate for tissue growth and organoid modeling

Hagfish exudate is a natural biological macromolecule made of keratin intermediate filament protein skeins and mucin vesicles. Here, we successfully examined this remarkable biomaterial as a substrate for three-dimensional (3D) cell culturing purposes. After the sterilization with chloroform vapor, Dulbecco's modified eagle medium was mixed with the exudate to rupture the vesicles and skeins; a highly soft, adherent, fibrous and biocompatible hydrogel was formed. A variety of cells, including Hela-FUCCI, NMuMG-FUCCI, 10T1/2 and C2C12, was cultured on the hagfish exudate. A remarkable 3D growth by ~2.5 folds after day 3, ~5 folds after day 5, ~10 folds after day 7 and ~15 folds after day 14 were seen compared to day one of culturing in the hagfish exudate scaffold. In addition, the phase contrast, fluorescent and confocal microscopy observations confirmed the organoid shape formation within the three-week culture. The viability of cells was almost 100% indicating the great in vitro and in vivo potential of this exceptional biomaterial with no cytotoxic effect.

An injectable carboxymethyl chitosan-methylcellulose-pluronic hydrogel for the encapsulation of meloxicam loaded nanoparticles

Hydrogel scaffolds have been frequently utilized due to their ability to absorb water and develop similar body cell conditions. Specific drug delivery to the tissues ensures less adverse side effects and more efficiency. In the present study, carboxymethyl chitosan (CMC)-methylcellulose (MC)-pluronic (P) and zinc chloride hydrogels containing meloxicam loaded into nanoparticles were developed and characterized. Nanoparticles were incorporated at 3.5, 4.5 and 5.5% (w/v). Hydrogels containing the same amounts of the meloxicam solution were also prepared. Gelation time, swelling and degradation of the hydrogels were investigated. Hydrogels were characterized by scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, and rheological analysis. Meloxicam release, chondrocytes attachment and growth on the hydrogels were also studied. Gelation time, swelling and the degradation rate of the hydrogels were found to be decreased by nanoparticles and increased with the addition of the meloxicam solution. SEM images also showed three-dimensional networks. The ATR-FTIR bands were shifted to the lower wave numbers in the hydrogels containing nanoparticles and shifted to the upper ones in the hydrogels containing meloxicam solution. Storage (G') and loss (G″) modulus were increased by the nanoparticles and reduced by the meloxicam solution. 100% of meloxicam was released from the hydrogels containing the meloxicam solution within 20 days, but it was released slowly from the hydrogels containing nanoparticles in 37days. Chondrocytes metabolic activity was increased on the 6th and 10th days for all hydrogels. Hydrogel containing nanoparticles showed good biocompatibility, bioadhesion, cell growth and expansion. The hydrogel could be, therefore, suitable as a new composite biomaterial for the regeneration of articular cartilage and meloxicam delivery to control the pain and inflammation in osteoarthritis.

Antitumor activity of a hydrogel loaded with lipophilic bismuth nanoparticles on cervical, prostate, and colon human cancer cells

The objective of this study was to analyze the antitumor activity of a hydrogel loaded with lipophilic bismuth nanoparticles on human cervical, prostate, and colon cancer cell lines. The effect of lipophilic bismuth nanoparticles on the viability of cancer cell lines (HeLa, DU145, and HCT-116) and non-cancer lung fibroblasts (HLF; LL 47[MaDo]) was determined with the MTT cell viability assay and compared with known antineoplastic drugs. The biocompatibility at an organismal level was verified in a murine model by histological examination. A lipophilic bismuth nanoparticle hydrogel at 50 µM time-dependently inhibited the growth of the three cancer cell lines, in a time-dependent way. A 1-hour exposure to 250 µM lipophilic bismuth nanoparticle hydrogel, inhibited the growth of the three cancer cell lines. The in-vitro efficacy of lipophilic bismuth nanoparticle was similar to the one of docetaxel and cisplatin, but without inhibiting the growth of non-cancer control cells. Histology confirmed the biocompatibility of lipophilic bismuth nanoparticles as there were no signs of cytotoxicity or tissue damage in any of the evaluated organs (kidney, liver, brain, cerebellum, heart, and jejunum). In conclusion, a lipophilic bismuth nanoparticle hydrogel is an innovative, low-cost alternative for the topical treatment of cervicouterine, prostate, and colon human cancers.