Toxicity, Biocompatibility, pH-Responsiveness and Methotrexate Release from PVA/Hyaluronic Acid Cryogels for Psoriasis Therapy

Targeting inflammation with hyaluronic acid-based micro- and nanotechnology: A disease-oriented review

Inflammation is a pivotal immune response in numerous diseases and presents therapeutic challenges. Traditional anti-inflammatory drugs and emerging cytokine inhibitors encounter obstacles such as limited bioavailability, poor tissue distribution, and adverse effects. Hyaluronic acid (HA), a versatile biopolymer, is widely employed to deliver therapeutic agents, including anti-inflammatory drugs, genes, and cell therapies owing to its unique properties, such as hydrophilicity, biodegradability, and safety. HA interacts with cell receptors to initiate processes such as angiogenesis, cell proliferation, and immune regulation. HA-based drug delivery systems offer dual strategies for effective inflammation management, capitalizing on passive and active mechanisms. This synergy permits the mitigation of inflammation by lowering the doses of anti-inflammatory drugs and their off-target adverse effects. A diverse array of micro- and nanotechnology techniques enable the fabrication of tailored HA-engineered systems, including hydrogels, microgels, nanogels, microneedles, nanofibers, and 3D-printed scaffolds, for diverse formulations and administration routes. This review explores recent insights into HA pharmacology in inflammatory conditions, material design, and fabrication methods, as well as its applications across a spectrum of inflammatory diseases, such as atherosclerosis, psoriasis, dermatitis, wound healing, rheumatoid arthritis, osteoarthritis, inflammatory bowel disease, and colitis, highlighting its potential for clinical translation.

Development, Characterization, and Evaluation of Potential Systemic Toxicity of a Novel Oral Melatonin Formulation

The need to create safe materials for biomedical and pharmaceutical applications has become a significant driving force for the development of new systems. Therefore, a chitosan-coated copolymer of itaconic acid, acrylic acid, and N-vinyl caprolactam (IT-AA-NVC) was prepared by radical polymerization and subsequent coating via nanoprecipitation to give a system capable of sustained delivery of melatonin. Although melatonin brings undoubted benefits to the human body, aspects of the optimal dose, route, and time of administration for the obtaining of suitable treatment outcomes remain under discussion. The entrapment of melatonin in biocompatible polymeric systems can prevent its oxidation, decrease its toxicity, and provide an increased half-life, resulting in an enhanced pharmacokinetic profile with improved patient compliance. The structures of the biopolymer and conjugate were proven by FTIR, thermal properties were tested by DSC, and the morphologies were followed by SEM. The loading efficiency and in vitro release profile were studied by means of HPLC, and a delayed release profile with an initial burst was obtained. The potential systemic toxicity of the formulation was studied in vivo; a mild hepatotoxicity was observed following administration of the melatonin-loaded formulation to mice, both by histopathology and blood clinical biochemistry. Histopathology showed a mild nephrotoxicity as well; however, kidney clinical biochemistry did not support this.

Exploring the Progress of Hyaluronic Acid Hydrogels: Synthesis, Characteristics, and Wide-Ranging Applications

This comprehensive review delves into the world of hyaluronic acid (HA) hydrogels, exploring their creation, characteristics, research methodologies, and uses. HA hydrogels stand out among natural polysaccharides due to their distinct features. Their exceptional biocompatibility makes them a top choice for diverse biomedical purposes, with a great ability to coexist harmoniously with living cells and tissues. Furthermore, their biodegradability permits their gradual breakdown by bodily enzymes, enabling the creation of temporary frameworks for tissue engineering endeavors. Additionally, since HA is a vital component of the extracellular matrix (ECM) in numerous tissues, HA hydrogels can replicate the ECM's structure and functions. This mimicry is pivotal in tissue engineering applications by providing an ideal setting for cellular growth and maturation. Various cross-linking techniques like chemical, physical, enzymatic, and hybrid methods impact the mechanical strength, swelling capacity, and degradation speed of the hydrogels. Assessment tools such as rheological analysis, electron microscopy, spectroscopy, swelling tests, and degradation studies are employed to examine their attributes. HA-based hydrogels feature prominently in tissue engineering, drug distribution, wound recovery, ophthalmology, and cartilage mending. Crafting HA hydrogels enables the production of biomaterials with sought-after qualities, offering avenues for advancements in the realm of biomedicine.

Hyaluronic Acid Aerogels Made Via Freeze-Thaw-Induced Gelation

The biodegradability, biocompatibility, and bioactivity of hyaluronic acid (HA), a natural polysaccharide, combined with the low density, high porosity, and high specific surface area of aerogels attract interest for biomedical applications such as wound dressings. In this work, physically cross-linked HA aerogels were prepared via the freeze-thaw (FT) induced gelation method, solvent exchange, and drying with supercritical CO2. The morphology and properties of HA aerogels (volume shrinkage, density, and specific surface area) were investigated as a function of several process parameters: HA concentration, solution pH, number of FT cycles, and type of nonsolvent used during solvent exchange. We demonstrate that the HA solution pH plays a key role in the aerogel formation, as not all conditions result in materials with high specific surface area. HA aerogels were of low density (<0.2 g/cm3), high specific surface area (up to 600 m2/g), and high porosity (≥90%). Scanning electron microscopy pictures revealed that HA aerogels present a porous structure with meso- and small macropores. The results show that HA aerogels are promising biomaterials with tunable properties and internal structure that offer high potential as, e.g., wound dressings.

Cryogels: Advancing Biomaterials for Transformative Biomedical Applications

Cryogels, composed of synthetic and natural materials, have emerged as versatile biomaterials with applications in tissue engineering, controlled drug delivery, regenerative medicine, and therapeutics. However, optimizing cryogel properties, such as mechanical strength and release profiles, remains challenging. To advance the field, researchers are exploring advanced manufacturing techniques, biomimetic design, and addressing long-term stability. Combination therapies and drug delivery systems using cryogels show promise. In vivo evaluation and clinical trials are crucial for safety and efficacy. Overcoming practical challenges, including scalability, structural integrity, mass transfer constraints, biocompatibility, seamless integration, and cost-effectiveness, is essential. By addressing these challenges, cryogels can transform biomedical applications with innovative biomaterials.

Green synthesis of lignin-based nanoparticles as a bio-carrier for targeted delivery in cancer therapy

Polymeric magnetic nanoparticles have shown higher efficacy in cancer diagnosis and treatment than conventional chemotherapies. Lignin is an abundantly available natural polymer that can be selectively modified using a rapidly expanding toolkit of biocatalytic and chemical reactions to yield 'intelligent' theranostic-nanoprobes. We aim to valorize lignin to develop a natural polymeric-magnetic-nano-system for the targeted delivery of methotrexate. In the current study, we synthesized nanoparticles of lignin and iron oxide with methotrexate using a new approach of anti-solvent precipitation with ultrasonication. The ensuing nanoparticles are magnetic, smooth, polyhedral with characteristic dimension of 110-130 nm. The drug loading and encapsulation efficiencies were calculated to be 66.06 % and 64.88 %, respectively. The nanoparticles exhibit a concentration-dependent release of methotrexate for the initial 24 h, followed by sustained release. Moreover, formulation is non-hemolytic and scavenges radicals owing to the antioxidant property of lignin. Additionally, methotrexate delivered using the nanoparticles exhibited higher cytotoxicity in cellular-viability assays employing breast cancer and macrophage cell lines compared to the pure form of the drug. Synergistic action of lignin, iron oxide, and methotrexate contribute to enhanced caspase-3 activity and reduced glutathione levels in the breast cancer cells, as well as elevated internalization of the drug on account of increased receptor-mediated endocytosis.

Unidirectional Nanopore Dehydration Induces an Anisotropic Polyvinyl Alcohol Hydrogel Membrane with Enhanced Mechanical Properties

As a biocompatible, degradable polymer material, polyvinyl alcohol (PVA) can have a wide range of applications in the biomedical field. PVA aqueous solutions at room temperature can be cast into very thin films with poor mechanical strength via water evaporation. Here, we describe a novel dehydration method, unidirectional nanopore dehydration (UND). The UND method was used to directly dehydrate a PVA aqueous solution to form a water-stable, anisotropic, and mechanically robust PVA hydrogel membrane (PVAHM), whose tensile strength, elongation at break, and swelling ratio reached values of up to ~2.95 MPa, ~350%, and ~350%, respectively. The film itself exhibited an oriented arrangement of porous network structures with an average pore size of ~1.0 μm. At 70 °C, the PVAHMs formed were even more mechanically robust, with a tensile strength and elongation at break of 10.5 MPa and 891%, almost 3.5 times and 2 times greater than the PVAHM prepared at 25 °C, respectively. The processing temperature affects the velocity at which the water molecules flow unidirectionally through the nanopores, and could, thus, alter the overall transformation of the PVA chains into a physically crosslinked 3D network. Therefore, the temperature setting during UND can control the mechanical properties of the hydrogel membrane to meet the requirements of various biomaterial applications. These results show that the UND can induce the ordered rearrangement of PVA molecular chains, forming a PVAHM with superior mechanical properties and exhibiting a greater number of stronger hydrogen bonds. Therefore, the novel dehydration mode not only induces the formation of a mechanically robust and anisotropic PVA hydrogel membrane with a porous network structure and an average pore size of ~1.0 μm, but also greatly enhances the mechanical properties by increasing the temperature. It may be applied for the processing of water-soluble polymers, including proteins, as novel functional materials.

Development of Vaginal Carriers Based on Chitosan-Grafted-PNIPAAm for Progesterone Administration

Chitosan-based hydrogels possess numerous advantages, such as biocompatibility and non-toxicity, and it is considered a proper material to be used in biomedical and pharmaceutical applications. Vaginal administration of progesterone represents a viable alternative for maintaining pregnancy and reducing the risk of miscarriage and in supporting the corpus luteum during fertilization cycles. This study aimed to develop new formulations for vaginal administration of progesterone (PGT). A previously synthesized responsive chitosan-grafted-poly (N-isopropylacrylamide) (CS-g-PNIPAAm) was formulated in various compositions with polyvinyl alcohol (PVA) as external crosslinking agent to obtain pH- and temperature-dependent hydrogels; the hydrogels had the capacity to withstand shear forces encountered in the vagina due to its mechanism of swelling once in contact with vaginal fluids. Three different hydrogels based on grafted chitosan were analyzed via Fourier-transform infrared spectroscopy (FTIR), swelling tests, in vitro drug release, and bioadhesion properties by TA.XTplus texture analysis. A higher amount of PVA decreased the swelling and the bioadhesion capacities of the hydrogel. All hydrogels showed sensitivity to temperature and pH in terms of swelling and in vitro delivery characteristics. By loading progesterone, the studied hydrogels seemed to possess even higher sensitivity than drug-free matrices. The release profile of the active substance and the bioadhesion characteristics recommended the CS-g-PNIPAAm/PVA 80/20 +PGT (P1) hydrogel as a proper constituent for the vaginal formulation for progesterone administration.

Biopolymers for Surgical Applications

Biopolymers have gained significant attention as a class of polymer materials with a wide range of applications, especially in the medical and pharmaceutical field. Due to particular characteristics, such as biocompatibility, biodegradability, non-toxicity, and functionality, they have become promising candidates for various surgical applications, including as bioadhesives, sealants, wound dressings, sutures, drug carriers, coating materials, etc. Recent research shows that further modification of biopolymers by advanced techniques can improve their functionality i.e., antibacterial activity, cell viability, drug-releasing capability, good wet adhesion performance, and good mechanical properties. This mini review aims to provide a brief report on the type of biopolymers and recent developments regarding their use in various surgical applications.

Biological Evaluation of Azetidine-2-One Derivatives of Ferulic Acid as Promising Anti-Inflammatory Agents

The purpose of this study was to evaluate the in vivo biological potential of new azetidine-2-one derivatives of ferulic acid (6a–f). First, the in vivo acute toxicity of azetidine-2-one derivatives of ferulic acid on Swiss white mice was investigated and, based on the obtained results, it can be stated that the studied derivatives belong to compounds with moderate toxicity. The in vivo anti-inflammatory potential of these derivatives was determined in a model of acute inflammation induced by carrageenan in rats and in a chronic inflammation model induced in rats using the granuloma test. In the acute inflammation model, all the studied compounds had a maximum anti-inflammatory effect 24 h after administration, which suggests that these compounds may be classified, from a pharmacokinetic point of view, in the category of long-acting compounds. The most active compound in the series was found to be compound 6b. In the case of the chronic inflammation model, it was observed that the studied compounds (6a–f) reduced the formation of granulation tissue compared to the control group, having an intense effect of inhibiting the proliferative component. The most important inhibitory effect of inhibiting the proliferative component was recorded for compound 6b. Additionally, the investigation of liver function was performed by determining the serum levels of liver enzymes aspartate transaminase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and bilirubin (total and direct). The results showed that, in the series of azetidin-2-one derivatives, the liver enzymes concentration values were close to those recorded for the reference anti-inflammatories (diclofenac sodium and indomethacin) and slightly higher compared to the values for the healthy control group. At the end of the experiment, the animals were euthanized and fragments of liver, lung, and kidney tissue were taken from all groups in the study. These were processed for histopathological examination, and we noticed no major changes in the groups treated with the azetidine 2-one derivatives of ferulic acid compared to the healthy groups.

Multi-Stimuli Nanocomposite Therapeutic: Docetaxel Targeted Delivery and Synergies in Treatment of Human Breast Cancer Tumor

A versatile breast cancer-targeting nanocomposite therapeutic combining docetaxel (DXL), polyvinyl alcohol (PVA) network for controlled release, and silica-protected magnetic iron oxide nanoparticles (Fe3 O4 NPs) for targeted delivery and gold nanoparticles (AuNPs) for plasmonic photothermal therapy (PPTT) is presented in this work. First, the designed nanocomposite is magnetically directed for cancer-targeted therapy confirmed by computerized tomography (CT) scans. Second, 10% DXL by mass is loaded into PVA, a pH and temperature responsive gel, for controlled release. Third, PPTT is confirmed with Au/Fe3 O4 /PVA-10%DXL using a prototype circulation system and then for tumor treatment in vivo; Au/Fe3 O4 /PVA-10%DXL is conveniently directed and the entrapped DXL is selectively released (≈96%) via the interaction of green and near-infrared (NIR) light with the localized surface plasmon resonance of AuNPs. A 75% cell death is reported from in vitro studies with DXL doses as low as 20 µg mL-1 of Au/Fe3 O4 /PVA-10%DXL, and a 70% tumor growth inhibition is demonstrated by in vivo experiments with the biosafety studies confirming minimal side effects to other organs. Overall, the developed Au/Fe3 O4 /PVA-10%DXL has a strong potential to simultaneously enhance CT imaging contrast together with the targeted delivery of DXL.

The Role of Two-Step Blending in the Properties of Starch/Chitin/Polylactic Acid Biodegradable Composites for Biomedical Applications

The current research trend for excellent miscibility in polymer mixing is the use of plasticizers. The use of most plasticizers usually has some negative effects on the mechanical properties of the resulting composite and can sometimes make it toxic, which makes such polymers unsuitable for biomedical applications. This research focuses on the improvement of the miscibility of polymer composites using two-step mixing with a rheomixer and a mix extruder. Polylactic acid (PLA), chitin, and starch were produced after two-step mixing, using a compression molding method with decreasing composition variation (between 8% to 2%) of chitin and increasing starch content. A dynamic mechanical analysis (DMA) was used to study the mechanical behavior of the composite at various temperatures. The tensile strength, yield, elastic modulus, impact, morphology, and compatibility properties were also studied. The DMA results showed a glass transition temperature range of 50 °C to 100 °C for all samples, with a distinct peak value for the loss modulus and factor. The single distinct peak value meant the polymer blend was compatible. The storage and loss modulus increased with an increase in blending, while the loss factor decreased, indicating excellent compatibility and miscibility of the composite components. The mechanical properties of the samples improved compared to neat PLA. Small voids and immiscibility were noticed in the scanning electron microscopy images, and this was corroborated by X-ray diffraction graphs that showed an improvement in the crystalline nature of PLA with starch. Bioabsorption and toxicity tests showed compatibility with the rat system, which is similar to the human system.

New isoniazid derivatives with improved pharmaco-toxicological profile: Obtaining, characterization and biological evaluation

Tuberculostatic drugs are the most common drug groups with global hepatotoxicity. Awareness of potentially severe hepatotoxic reactions is vital, as hepatic impairment can be a devastating and often fatal condition. The treatment problems that may arise, within this class of medicines, are mainly of two types: adverse reactions (collateral, toxic or hypersensitive reactions) and the initial or acquired resistance of Mycobacterium tuberculosis to one or more antituberculosis drugs. Prevention of adverse reactions, increase treatment adherence and success rates, providing better control of tuberculosis (TB). In this regard, obtaining new drugs with low toxicity and high tuberculostatic potential is essential. Thus, in this work, we have designed or synthesized new derivatives of isoniazid (INH), such as new Isonicotinoylhydrazone (INH-a, INH-b and INH-c). These derivatives demonstrated good biocompatibility, antimicrobial property similar to that of parent isoniazid and last but not least, a significantly improved Pharmacotoxicological profile compared to that of isoniazid.

Chitosan-Graft-Poly(N-Isopropylacrylamide)/PVA Cryogels as Carriers for Mucosal Delivery of Voriconazole

The objective of this study was to prepare and characterize physically crosslinked gel formulations of chitosan (CS)-graft-poly(N-isopropyl acrylamide) (PNIPAAm) and polyvinyl alcohol (PVA) for smart delivery of an antifungal drug, Voriconazole, for mucosal applications. For this purpose, cryogels of CS-g-PNIPAAm/PVA and CS/PVA were tested by means of texture profile analysis and rheology to determine optimal matrix properties for topical application. The ratio of 75/25 v/v % CS-g-PNIPAAm/PVA was selected to be used for formulation since it gave low compressibility and hardness (1.2 and 0.6 N) as well as high adhesion properties and non-Newtonian flow behavior. The cryogels and formulations were further characterized by means of FTIR spectroscopy, swelling behavior, texture analysis, scanning electron microscopy (SEM), thermal (differential scanning calorimetry (DSC) and TGA), and rheological behavior. The drug loading capacity and in vitro release profile of the drug, storage stability, and cytotoxicity tests were also performed for the gel formulation. The FTIR, DSC, and TGA results verified the successful formation of cryogels. Swelling studies revealed a pH-dependent swelling ability with a maximum swelling degree of 1200% in acid and 990% in phosphate buffer (pH = 7.4). Thermal studies showed that CS-g-PNIPAAm/PVA 75/25 had higher thermal stability proving the structural complexity of the polymer. The loading capacity of Voriconazole was found to be 70% (w/w). The in vitro release profiles of Voriconazole showed Fickian release behavior for CS-g-PNIPAAm/PVA 75/25 gel with an approximate delivery of 38% within 8 h, slower than matrices containing unmodified chitosan. The storage stability test exhibited that the gel formulation was still stable even after aging for two months. Moreover, the cell culture assays revealed a non-toxic character of the polymeric matrix. Overall results showed that the CS-g-PNIPAAm/PVA 75/25 hydrogel has the potential to be used as a smart polymeric vehicle for topical applications.

Injectable Click-Crosslinked Hyaluronic Acid Depot To Prolong Therapeutic Activity in Articular Joints Affected by Rheumatoid Arthritis

The aim of this study was to design a click-crosslinked hyaluronic acid (HA) (Cx-HA) depot via a click crosslinking reaction between tetrazine-modified HA and trans-cyclooctene-modified HA for direct intra-articular injection into joints affected by rheumatoid arthritis (RA). The Cx-HA depot had significantly more hydrogel-like features and a longer in vivo residence time than the HA depot. Methotrexate (MTX)-loaded Cx-HA (MTX-Cx-HA)-easily prepared as an injectable formulation-quickly formed an MTX-Cx-HA depot that persisted at the injection site for an extended period. In vivo MTX biodistribution in MTX-Cx-HA depots showed that a high concentration of MTX persisted at the intra-articular injection site for an extended period, with little distribution of MTX to normal tissues. In contrast, direct intra-articular injection of MTX alone or MTX-HA resulted in rapid clearance from the injection site. After intra-articular injection of MTX-Cx-HA into rats with RA, we noted the most significant RA reversal, measured by an articular index score, increased cartilage thickness, extensive generation of chondrocytes and glycosaminoglycan deposits, extensive new bone formation in the RA region, and suppression of tumor necrosis factor-α or interleukin-6 expression. Therefore, MTX-Cx-HA injected intra-articularly persists at the joint site in therapeutic MTX concentrations for an extended period, thus increasing the duration of RA treatment, resulting in an improved relief of RA.

Functional Hydrogels With Tunable Structures and Properties for Tissue Engineering Applications

Tissue engineering (TE) has been used as an attractive and efficient process to restore the original tissue structures and functions through the combination of biodegradable scaffolds, seeded cells, and biological factors. As a unique type of scaffolds, hydrogels have been frequently used for TE because of their similar 3D structures to the native extracellular matrix (ECM), as well as their tunable biochemical and biophysical properties to control cell functions such as cell adhesion, migration, proliferation, and differentiation. Various types of hydrogels have been prepared from naturally derived biomaterials, synthetic polymers, or their combination, showing their promise in TE. This review summarizes the very recent progress of hydrogels used for TE applications. The strategies for tuning biophysical and biochemical properties, and structures of hydrogels are first introduced. Their influences on cell functions and promotive effects on tissue regeneration are then highlighted.