Development of a gallic acid-loaded chitosan and polyvinyl alcohol hydrogel composite: Release characteristics and antioxidant activity

Functional network copolymeric hydrogels derived from moringa gum: Physiochemical, drug delivery and biomedical properties

The article explores the synthesis of network hydrogels derived from moringa gum (MG) through a grafting reaction with poly (vinylsulfonic acid) and carbopol. These hydrogels are designed for use in drug delivery (DD) and wound hydrogels dressing (HYDR) applications. The copolymers were characterized by FESEM, EDX, AFM, FTIR, 13C NMR, XRD and DSC. Tetracycline release from hydrogel occurred gradually with a non-Fickian diffusion and was best described by the Hixson-Crowell kinetic model in artificial wound fluid. The HYDR demonstrated compatibility with blood, exhibited antioxidant properties and possessed tensile strength, in addition to their mucoadhesive characteristics. The copolymer dressings absorbed approximately 7 g of simulated fluid. The copolymers exhibited significant antioxidant activity, measuring at 84 % free radicals scavenging, during DPPH assay. These dressings demonstrated permeability to H2O and O2,. The hydrogel alone did not reveal antibacterial activities; however, when combined with antibiotic drug tetracycline, the dressings revealed notable antibacterial activities against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The observed biomedical properties suggested that these hydrogels could serve as promising materials for drug delivery HYDR applications.

An insight into the antioxidant activities and the exploration of record high quantities of quercetin and luteolin in the plant parts of Myxopyrum smilacifolium (wall.) Blume

This study attempts to reveal antioxidants in the plant parts of Myxopyrum smilacifolium (Wall.) Blume using antioxidant assays and LC-MS/MS analysis. Methanol is the most effective solvent for collecting antioxidants. The roots-derived methanol extract demonstrates the greatest antioxidant activity, corresponding to the extremely low IC50 values of 16.39 µg/mL and 19.80 µg/mL for DPPH and ABTS radicals, respectively. The high phenolic and flavonoid contents are the primary reason for outstanding total antioxidant capacity (TAC; i.e. 247.73 ± 1.62 mg GA/g or 163.93 ± 0.83 mg AS/g) of the root extract. LC-MS/MS quantification of five phenolic compounds reveals exceptionally high amounts of quercetin and luteolin in the root extract, ranging from 238.86 ± 5.74 to 310.99 ± 1.44 µg/g and from 201.49 ± 7.84 to 234.10 ± 2.54 µg/g, respectively, in the root-derived methanol extract. The achievement highlights M. smilacifolium as a promising source of natural antioxidants for large-scale medical applications.

Sponge-like porous polyvinyl alcohol/chitosan-based hydrogel with integrated cushioning, pH-indicating and antibacterial functions

Developing a packaging material with integrated cushioning, intelligent and active functions is highly desired but remains challenging in the food industry. Here we show that a sponge-like porous hydrogel with pH-indicating and antibacterial additives can meet this requirement. We use polyvinyl alcohol and chitosan as the primary polymers to construct a hydrogel with hierarchical structures through a freeze-casting method in combination with salting-out treatment. The synergy of aggregated polymer chains and the sponge-like porous structure makes the hydrogel resilient and efficient in energy absorption. It also enables rapid movement of molecules/particles and fast reaction due to the large specific surface area of the pore structures and the large amount of free water in it, leading to a sensitive pH-indicating function. The hydrogel shows an obvious color variation within a wide pH range in 3 min. The silver nanoparticles are fixed in the dense polymer networks, enabling a lasting release of silver ions. The porous structure makes the silver ion reach the protected item in a short time, achieving an antibacterial effect against S. aureus and E. coli with little cytotoxicity. This work paves the way for fabricating multifunctional hydrogels for diverse advanced packaging systems.

Construction of self-assembled nano cellulose crystals/chitosan nanobubbles composite hydrogel with improved gallic acid release property

Hydrogels are of great significance in the field of bioactive delivery. This study designed the self-assembly of gallic acid-loaded nano cellulose crystals/chitosan (NC/CS) hydrogels via Nano bubbles (NBs). NC/CS NBs 4:2 hydrogels improved the mechanical properties compared to those without NBs. The hardness of NC/CS (4:2) NBs hydrogels was greatly enhanced by 1.15 ± 0.05. The water-holding and swelling behavior can be tuned at different ratios. NC/CS NBs (4:2) showed the electrostatic interaction analyzed by FTIR, XRD, and XPS. SEM results displayed smoother and smaller pores along dense networks promoted by NBs. The antioxidant activity of hydrogels was increased by adding NBs (P < 0.05). In vitro and vivo release activity of gallic acid was higher in simulated intestinal fluid (SIF) at 4:2, depicting the controlled release mechanism. Thus, current work revealed that NBs and low concentrations of NC can be self-assembled with chitosan chains, producing a highly compact hydrogel structure.

Designing a bi-layer multifunctional hydrogel patch based on polyvinyl alcohol, quaternized chitosan and gallic acid for abdominal wall defect repair

In abdominal wall defect repair, surgical site infection (SSI) remains the primary cause of failure, while complications like visceral adhesions present significant challenges following patch implantation. We designed a Janus multifunctional hydrogel patch (JMP) with antibacterial, anti-inflammatory, and anti-adhesive properties. The patch comprises two distinct layers: a pro-healing layer and an anti-adhesion layer. The pro-healing layer was created by a simple mixture of polyvinyl alcohol (PVA), quaternized chitosan (QCS), and gallic acid (GA), crosslinked to form PVA/QCS/GA (PQG) hydrogels through GA's self-assembly effect and hydrogen bonding. Additionally, the PVA anti-adhesive layer was constructed using a drying-assisted salting method, providing a smooth and dense physical barrier to prevent visceral adhesion while offering essential mechanical support to the abdominal wall. The hydrogel patch demonstrates widely adjustable mechanical properties, exceptional biocompatibility, and potent antimicrobial properties, along with a sustained and stable release of antioxidants. In rat models of skin and abdominal wall defects, the JMP effectively promoted tissue healing by controlling infection, inhibiting inflammation, stimulating neovascularization, and successfully preventing the formation of visceral adhesions. These compelling results highlight the JMP's potential to improve the success rate of abdominal wall defect repair and reduce surgical complications.

A hydrogen-bonded curdlan-chitosan/polyvinyl alcohol edible dual functional hydrogel bandage against MRSA promotes wound healing

The most prevalent complication arising from skin injuries is bacterial infection, where pathogenic bacteria proliferate significantly at the wound site, leading to subsequent complications like septic shock and sepsis. Although antibiotics presently effectively manage wound infections caused by common bacteria, the escalating prevalence of antibiotic-resistant strains necessitates urgent novel approaches for addressing such infections. Here, we present CS9P1-RA, a dual functional hydrogel dressing, based on polyvinyl alcohol (PVA) matrix crosslinked through hydrogen bonding. CS9P1-RA combines chitosan (CS), a food-derived antibacterial agent, with the natural compound rosmarinic acid (RA) to specifically target skin injuries caused by MRSA. Computational and molecular biology assays illustrate RA's ability to selectively inhibit the activity of Staphylococcus aureus (S. aureus) serine/threonine phosphatase (Stp1), reducing the S. aureus pathogenicity. CS9P1-RA showcases exceptional antibacterial efficacy (MIC = 1 mg/mL) and demonstrates potency in reducing virulence (IC50 = 7.424 μM on Stp1). Notably, it effectively curbs bacterial growth and accelerates wound healing in the mice model, thereby fulfilling the practical requirements for clinical applications. Moreover, the mechanical properties of CS9P1-RA ensure user comfort during treatment. This work introduces a fresh design paradigm for dressing materials, offering a promising solution for treating skin injuries inflicted by antibiotic-resistant bacterial infections.

Effects of Phenolics on the Physicochemical and Structural Properties of Collagen Hydrogel

In the current era, the treatment of collagen hydrogels with natural phenolics for the improvement in physicochemical properties has been the subject of considerable attention. The present research aimed to fabricate collagen hydrogels cross-linked with gallic acid (GA) and ellagic acid (EA) at different concentrations depending on the collagen dry weight. The structural, enzymatic, thermal, morphological, and physical properties of the native collagen hydrogels were compared with those of the GA/EA cross-linked hydrogels. XRD and FTIR spectroscopic analyses confirmed the structural stability and reliability of the collagen after treatment with either GA or EA. The cross-linking also significantly contributed to the improvement in the storage modulus, of 435 Pa for 100% GA cross-linked hydrogels. The thermal stability was improved, as the highest residual weight of 43.8% was obtained for the hydrogels cross-linked with 50% GA in comparison with all the other hydrogels. The hydrogels immersed in 30%, 50%, and 100% concentrations of GA also showed improved swelling behavior and porosity, and the highest resistance to type 1 collagenase (76.56%), was obtained for 50% GA cross-linked collagen hydrogels. Moreover, GA 100% and EA 100% obtained the highest denaturation temperatures (Td) of 74.96 °C and 75.78 °C, respectively. In addition, SEM analysis was also carried out to check the surface morphology of the pristine collagen hydrogels and the cross-linked collagen hydrogels. The result showed that the hydrogels cross-linked with GA/EA were denser and more compact. However, the improved physicochemical properties were probably due to the formation of hydrogen bonds between the phenolic hydroxyl groups of GA and EA and the nitrogen atoms of the collagen backbone. The presence of inter- and intramolecular cross-links between collagen and GA or EA components and an increased density of intermolecular bonds suggest potential hydrogen bonding or hydrophobic interactions. Overall, the present study paves the way for further investigations in the field by providing valuable insights into the GA/EA interaction with collagen molecules.

Versatile and User-Friendly Anti-infective Hydrogel for Effective Wound Healing

Wound dressings play a crucial role in facilitating optimal wound healing and protecting against microbial infections. However, existing commercial options often fall short in addressing chronic infections due to antibiotic resistance and the limited spectrum of activity against both Gram-positive and Gram-negative bacteria frequently encountered at wound sites. Additionally, complex fabrication processes and cumbersome administration strategies pose challenges for cost-effective wound dressing development. Consequently, there is a pressing need to explore easily engineered biocompatible biomaterials as alternative solutions to combat these challenging wound infections. In this study, we present the development of an anti-infective hydrogel, P-BAC (polymeric bactericidal hydrogel), which exhibits simple administration and promotes efficient wound healing. P-BAC is synthesized via a one-step fabrication method that involves the noncovalent cross-linking of poly(vinyl alcohol), N-(2-hydroxypropyl)-3-trimethylammonium chitosan chloride-AgCl nanocomposite, and proline. Remarkably, P-BAC demonstrates broad-spectrum antibacterial activity against both planktonic and stationary cells of clinically isolated Gram-positive and Gram-negative bacteria, resulting in a significant reduction of bacterial load (5-7 log reduction). Moreover, P-BAC exhibits excellent efficacy in eradicating bacterial cells within biofilm matrices (>95% reduction). In vivo experiments reveal that P-BAC accelerates wound healing by stimulating rapid collagen deposition at the wound site and effectively inactivates ∼95% of Pseudomonas aeruginosa cells. Importantly, the shear-thinning property of P-BAC simplifies the administration process, enhancing its practicality and usability. Taken together, our findings demonstrate the potential of this easily administrable hydrogel as a versatile solution for effective wound healing with potent anti-infective properties. The developed hydrogel holds promise for applications in diverse healthcare settings, addressing the critical need for improved wound dressing materials.

β-Tricalcium Phosphate-Loaded Chitosan-Based Thermosensitive Hydrogel for Periodontal Regeneration

The current treatment for periodontitis is aimed at resolving gingival inflammation, whilst complete periodontal tissue regeneration is not predictable, and it represents a therapeutic challenge. Injectable biomaterials hold tremendous potential in dental tissue regeneration. This study aimed to investigate the ability of an injectable thermosensitive β-tricalcium phosphate (β-TCP) and chitosan-based hydrogel to carry cells and promote periodontal tissue regeneration. In this study, different concentrations of β-TCP-loaded chitosan hydrogels were prepared (0%, 2%, 4%, or 6% β-TCP, 10% β-glycerol phosphate, and 1.5% chitosan). The characteristics of the hydrogels were tested using rheology, a scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), degradation, and biological analyses. The new biomaterial showed a sol-gel transformation ability at body temperature and exhibited excellent chemical and physical characteristics, whilst the existence of β-TCP enhanced the structure and the properties of the hydrogels. The SEM confirmed the three-dimensional networks of the hydrogels, and the typical rheological properties of strong gel were observed. The EDX and XRD validated the successful incorporation of β-TCP, and similar patterns between different groups were found in terms of the FTIR spectra. The stable structure of the hydrogels under 100 °C was confirmed via DSC. Biological tests such as Alamar Blue assay and Live/Dead staining confirmed the remarkable biocompatibility of the hydrogels with pre-osteoblast MC3T3-E1 and human gingival fibroblast (HGF) cells for 14 days, and the results were validated with confocal imaging. This preliminary study shows great promise for the application of the β-TCP-loaded thermosensitive chitosan hydrogels as a scaffold in periodontal bone and soft tissue repair.

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.

Application of polyvinyl alcohol/chitosan copolymer hydrogels in biomedicine: A review

Hydrogels is a hydrophilic, cross-linked polymer of three-dimensional network structures. The application of hydrogels prepared from a single polymer in the biomedical field has many drawbacks. The functional blend of polyvinyl alcohol and chitosan allows hydrogels to have better and more desirable properties than those produced from a single polymer, which is a good biomaterial for development and design. In this paper, we have reviewed the progress in the application of polyvinyl alcohol/chitosan composite hydrogels in various medical fields, the different cross-linking agents and cross-linking methods, and the research progress in the optimization of composite hydrogels for their subsequent wide range of biomedical applications.

Improved hydrophobicity, antibacterial and mechanical properties of polyvinyl alcohol/quaternary chitosan composite films for antibacterial packaging

Polyvinyl alcohol (PVA) and chitosan (CS) are attractive polymeric feedstocks for developing eco-environmental materials. In this work, a biodegradable and antibacterial film was developed based on PVA blending with different long-chain alkyl and different contents of quaternary chitosan through solution casting, in which quaternary chitosan not only acted as an antibacterial agent but also improved hydrophobicity and mechanical properties. A novel peak appeared at 1470 cm^-1 in Transform Infrared Spectroscopy (FTIR) and a new CCl bond spectral peak at 200 eV in X-ray photoelectron spectroscopy (XPS) spectra suggested that CS was successfully modified by quaternary. Besides, the modified films have better antibacterial effects against Escherichia (E. coli) and Staphylococcus (S. aureus) and present stronger antioxidant properties. Optical properties demonstrated that the light transmittance on both UV and visible light showed a decreasing trend with the increase of the quaternary chitosan contents. Whereas the composite films have enhanced hydrophobicity than PVA film. Furthermore, the composite films had higher mechanical properties, in which Young's modulus, tensile strength, and elongation at break were 344.99 MPa, 39.12 MPa, and 507.09 %, respectively. This research demonstrated that the modified composite films could extend the shelf of life on antibacterial packaging.

Construction of an antibacterial hydrogel based on diammonium glycyrrhizinate and gallic acid for bacterial- infected wound healing

The current antibacterial wound dressings with antibiotic substances or metal bactericidal agents may lead to severe multidrug resistance and poor biocompatibilities. Herein, we report an inherent antibacterial hydrogel constructed by only two naturally small molecules gallic acid (GA) and diammonium glycyrrhizinate (DG) for promoting Staphylococcus aureus (S. aureus)-infected wound healing. The resultant GAD hydrogel can be fabricated by co-assembly of these two materials through simple steps. Thanks to the incorporation of GA and DG, GAD hydrogel enabled a strong mechanical performance and great self-healing property with a sustained-release of drugs into skin wounds. Moreover, the cell viability assays showed that GAD hydrogel had good cytocompatibility by promoting cell proliferation and migration. In addition, GAD hydrogel had broad antibacterial efficiency against both Gram-positive and Gram-negative bacteria. Taken together, GAD hydrogel is a promising dressing to accelerate bacterial-infected wound healing through reconstructing an intact and thick epidermis without antibiotics or cytokines.

Bilayer nanofibrous wound dressing prepared by electrospinning containing gallic acid and quercetin with improved biocompatibility, antibacterial, and antioxidant effects

OBJECTEIVES

The purpose of this study was to prepare an antibacterial, antioxidant, and biocompatible bilayer nanofibrous wound dressing by using electrospinning.

METHODS

The micromorphology and bilayer structure characteristics of the GA-Qe-PVP-PCL nanofibers were analyzed by SEM. The physicochemical characteristics were analyzed by XRD and FTIR. The uptake, mechanical properties, water contact angle, water vapor transmission and in vitro drug release were evaluated. In addition, the effect of antibacterial, antioxidant and biocompatability of the nanofibers were evaluated, respectively.

RESULTS

The SEM results showed that the GA-Qe-PVP-PCL nanofibers had a smooth surface, no beading phenomenon, and a prominent bilayer structure. The diameter and porosity of the drug-loading layer and waterproof support layer of the nanofibers were 842 ± 302 nm, 242 ± 50 nm, and 88.56 ± 1.67%, 94.49 ± 1.57%, respectively. Moreover, the water uptake, mechanical properties, water contact angle, and water vapor transmission showed ideal performance. The results of in vitro drug release indicated that GA and Qe were both released rapidly, which was conducive to accelerating wound healing. The GA-Qe-PVP-PCL nanofibers exhibited antibacterial effects against both bacteria as well as high antioxidant activity. Additionally, the GA-Qe-PVP-PCL nanofibers possessed good compatibility, could promote the proliferation, adhesion, and migration of L929 fibroblast cells.

CONCLUSION

The nanofibers we developed met the requirements of ideal materials for wound dressing, which makes the nanofibers the potential to be a wound dressing for wound care.

Highly stretchable, self-healing, and degradable ionic conductive cellulose hydrogel for human motion monitoring

Self-healing biomass-based conductive hydrogels are applied as flexible strain sensors for wearable devices and human movement monitoring. Cellulose is the most abundant biomass-based materials and exhibits excellent toughness, dispersion and degradability. In this paper, nanocellulose crystals (NCCs) prepared from sisal, used as reinforcing fillers were coated with tannic acid (TA) to prepare inexpensive bio-nanocomposite hydrogels that also included polyvinyl alcohol, okra polysaccharide (OP), and borax. These hydrogels exhibit excellent self-healing and mechanical properties with the maximum elongation, toughness, and self-healing efficiency (9 min) of 1426.2 %, 264.4 kJ/m³, and 62.1 %, respectively. A fabricated hydrogel strain sensor was successfully used to detect and monitor various human movements such as wrist bending, elbow bending, and slight changes in facial expression. In addition, this sensor possessed excellent durability and good working stability after repeated circulation. The nanocomposite hydrogel synthesized in this work utilized natural polysaccharide to manufacture flexible functional materials with good application prospects in the field of flexible sensors.

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.

Quercetin/Hydroxypropyl-β-Cyclodextrin Inclusion Complex-Loaded Hydrogels for Accelerated Wound Healing

This study concentrated on developing quercetin/cyclodextrin inclusion complex-loaded polyvinyl alcohol (PVA) hydrogel for enhanced stability and solubility. Quercetin was encapsulated in hydroxypropyl-β-cyclodextrin (HP-β-CD) by the solvent evaporation method. The prepared quercetin/HP-β-CD inclusion complex showed 90.50 ± 1.84% encapsulation efficiency (%EE) and 4.67 ± 0.13% loading capacity (%LC), and its successful encapsulation was confirmed by FT-IR and XRD. The quercetin/HP-β-CD inclusion complex was well dispersed in viscous solutions of PVA in various amounts (0.5, 1.0, 1.5. 2.5, and 5.0% w/v ratio), and the drug-loaded polymer solution was physically crosslinked by multiple freeze–thaw cycles to form the hydrogel. The cumulative amount of quercetin released from the prepared hydrogels increased with increasing concentrations of the inclusion complex. The introduction of the inclusion complex into the PVA hydrogels had no influence on their swelling ratio, but gelation and compressive strength reduced with increasing inclusion complex concentration. The potential cytotoxicity of quercetin/HP-β-CD inclusion complex hydrogels was evaluated by MTT assay and expressed as % cell viability. The results show biocompatibility toward NCTC 929 clone cells. The inhibitory efficacy was evaluated with 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay, and the results show a higher level of antioxidant activity for quercetin/HP-β-CD inclusion complex hydrogels compared with free quercetin. The findings of our study indicate that the developed quercetin/HP-β-CD inclusion complex hydrogels possess the required properties and can be proposed as a quercetin delivery system for wound-healing applications.

Hollow mesoporous silica nanoparticles-loaded ion-crosslinked bilayer films with excellent mechanical properties and high bioavailability for buccal delivery

Mucoadhesive buccal films (MBFs) become the most promising buccal mucosal delivery system duo to its advantageous properties, including simple preparation technique and better patient compliance. The mechanical properties and mucoadhesion of MBFs are crucial in their successful performance as well as manufacturing and administration. In this study, we prepared hollow mesoporous silica nanoparticles-loaded ion-crosslinked bilayer films (CCS-PVA-TPP-FSM@HMSNs) using carboxymethyl chitosan (CCS) and polyvinyl alcohol (PVA) for buccal delivery of furosemide (FSM). The FSM-loaded hollow mesoporous silica nanoparticles (FSM@HMSNs) were firstly characterized by SEM, TEM, and nitrogen adsorption/desorption. Then, we constructed an ion-crosslinked network using CCS and PVA employed with the solution casting method, and sodium tripolyphosphate (TPP) was used as a hydrogen bond crosslinking agent. The formulation was optimized through Box-Behnken design, where the impact of the proportion of the ingredients on the quality of the films was evaluated entirely. Herein, folding endurance, swelling, tensile strength, and adhesion force were selected as response variables. Morphology, mechanical, spectroscopic, thermal, and safety of CCS-PVA-TPP-FSM@HMSNs films were also investigated. The release and permeability behaviors of CCS-PVA-TPP-FSM@HMSNs films were evaluated by in vitro drug release, across isolated porcine buccal and TR146 cell model. The CCS-PVA-TPP-FSM@HMSNs films showed outstanding mechanical properties, suitable bioadhesion, high drug loading, significant sustained-release properties, and improved permeability. In pharmacokinetic study with golden hamster models, the relative bioavailability was increased by 191.54%, and the absolute bioavailability was 82.20%. In summary, this study provides evidence that this innovative CCS-PVA-TPP-FSM@HMSNs films could be a promising and industrialized buccal drug delivery system.

Preparation of a Chitosan-Lead Composite Carbon Aerogel and Its Catalytic Thermal Decomposition Performance on Ammonium Perchlorate

Chitosan-lead (CS-Pb) carbon aerogels were prepared by ionic cross-linking and high-temperature carbonization using chitosan (CS) as the carbon precursor. The obtained carbon aerogels were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). The obtained aerogels have a 3D structure and a large surface area, which can effectively prevent the agglomeration phenomenon of metals. Differential thermal analysis (DTA) was used to analyze the catalytic performance of a carbon aerogel for ammonium perchlorate (AP). The results showed that the CS-Pb carbon aerogel reduced the peak temperature of AP pyrolysis from 703.9 to 627.7 K. According to the Kissinger method calculations, the E_a of AP decomposition decreased about 27.2 kJ/mol. The TG data at different warming rates were analyzed by the Flynne-Walle-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods, which are two of the isoconversion methods, and the activation energies of AP and AP+CS-Pb-3.5 were calculated. Between the conversion degrees (α) of 0.1 and 0.9, the E_a values obtained by the two isoconversion methods are similar and have a certain match. Also, the two isoconversion methods confirm Kissinger's calculation. Finally, thermogravimetry-mass spectrometry (TG-MS) was used to monitor the gases generated during the thermal decomposition of the AP+CS-Pb-3.5 system in real time.

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.

The beauty of biocatalysis: sustainable synthesis of ingredients in cosmetics

Covering: 2015 up to July 2021The market for cosmetics is consumer driven and the desire for green, sustainable and natural ingredients is increasing. The use of isolated enzymes and whole-cell organisms to synthesise these products is congruent with these values, especially when combined with the use of renewable, recyclable or waste feedstocks. The literature of biocatalysis for the synthesis of ingredients in cosmetics in the past five years is herein reviewed.

Antimicrobial Food Packaging with Biodegradable Polymers and Bacteriocins

Innovations in food and drink packaging result mainly from the needs and requirements of consumers, which are influenced by changing global trends. Antimicrobial and active packaging are at the forefront of current research and development for food packaging. One of the few natural polymers on the market with antimicrobial properties is biodegradable and biocompatible chitosan. It is formed as a result of chitin deacetylation. Due to these properties, the production of chitosan alone or a composite film based on chitosan is of great interest to scientists and industrialists from various fields. Chitosan films have the potential to be used as a packaging material to maintain the quality and microbiological safety of food. In addition, chitosan is widely used in antimicrobial films against a wide range of pathogenic and food spoilage microbes. Polylactic acid (PLA) is considered one of the most promising and environmentally friendly polymers due to its physical and chemical properties, including renewable, biodegradability, biocompatibility, and is considered safe (GRAS). There is great interest among scientists in the study of PLA as an alternative food packaging film with improved properties to increase its usability for food packaging applications. The aim of this review article is to draw attention to the existing possibilities of using various components in combination with chitosan, PLA, or bacteriocins to improve the properties of packaging in new food packaging technologies. Consequently, they can be a promising solution to improve the quality, delay the spoilage of packaged food, as well as increase the safety and shelf life of food.

Blended Natural Support Materials-Collagen Based Hydrogels Used in Biomedicine

Due to their unique properties-the are biocompatible, easily accessible, and inexpensive with programmable properties-biopolymers are used in pharmaceutical and biomedical research, as well as in cosmetics and food. Collagen is one of the most-used biomaterials in biomedicine, being the most abundant protein in animals with a triple helices structure, biocompatible, biomimetic, biodegradable, and hemostatic. Its disadvantages are its poor mechanical and thermal properties and enzymatic degradation. In order to solve this problem and to use its benefits, collagen can be used blended with other biomaterials such as alginate, chitosan, and cellulose. The purpose of this review article is to offer a brief paper with updated information on blended collagen-based formulations and their potential application in biomedicine.

Preparation of chitosan/hydrolyzed collagen/hyaluronic acid based hydrogel composite with caffeic acid addition

In this work, biopolymer hydrogels were synthesized by mixing hyaluronic acid, hydrolyzed collagen, and chitosan through a solvent evaporation method and incorporating them with caffeic acid as an antioxidant agent. The obtained caffeic acid-loaded chitosan/hydrolyzed collagen/hyaluronic acid hydrogels were characterized by X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis. No significant change on structural and thermal properties was observed. Furthermore, scanning electron microscope reported that the surface morphology of the hydrogels was smooth, and no significant change in porosity was observed after the addition of hyaluronic acid. With high amount of hyaluronic acid, the swelling behaviour was superiority. The hydrogels showed an initial burst release of caffeic acid (~70%) within 60 min, followed by a gradual release of up to 80% by 480 min. The release was slightly higher with the presence of hyaluronic acid. In addition, DPPH, ABTS⁺, and FRAP assays revealed that the caffeic acid-loaded hyaluronic acid/hydrolyzed collagen/chitosan hydrogels exhibited antioxidant activity. Thus, these composites could potentially be used as dressing materials with antioxidant activity.

Recent Advances in Polymer Nanomaterials for Drug Delivery of Adjuvants in Colorectal Cancer Treatment: A Scientific-Technological Analysis and Review

Colorectal cancer (CRC) is the type with the second highest morbidity. Recently, a great number of bioactive compounds and encapsulation techniques have been developed. Thus, this paper aims to review the drug delivery strategies for chemotherapy adjuvant treatments for CRC, including an initial scientific-technological analysis of the papers and patents related to cancer, CRC, and adjuvant treatments. For 2018, a total of 167,366 cancer-related papers and 306,240 patents were found. Adjuvant treatments represented 39.3% of the total CRC patents, indicating the importance of adjuvants in the prognosis of patients. Chemotherapy adjuvants can be divided into two groups, natural and synthetic (5-fluorouracil and derivatives). Both groups can be encapsulated using polymers. Polymer-based drug delivery systems can be classified according to polymer nature. From those, anionic polymers have garnered the most attention, because they are pH responsive. The use of polymers tailors the desorption profile, improving drug bioavailability and enhancing the local treatment of CRC via oral administration. Finally, it can be concluded that antioxidants are emerging compounds that can complement today's chemotherapy treatments. In the long term, encapsulated antioxidants will replace synthetic drugs and will play an important role in curing CRC.

Reactive Nitrogen Species Releasing Hydrogel for Enhanced Wound Healing

Poor proliferation and migration of fibroblast, keratinocyte and endothelial cells delays the wound healing in diabetic patients and results into chronicity of wounds. Slow or decreased formation of blood vessels is another issue that increases the chronicity of non-healing wounds. These chronic wounds turn into an ulcer that may lead to limb amputation. Recently, nitric oxide (NO) has emerged as a potential agent for accelerating cell migration and proliferation to enhance wound healing. It increases the expression of necessary angiogenic growth factors which stimulates the proliferation and migration of major cell types involved in wound repair. Here we report the synthesis of chitosan (CS), polyvinyl alcohol (PVA) and a NO donor S-nitroso-N-acetyl-DL-penicillamine (SNAP) to enhance the wound healing activities in chronic wounds. A three-fold increase in the proliferation of 3T3 cells was observed with NO-releasing CS-PVA hydrogels. In vitro cell migration assay demonstrated a four-fold faster migration of cells to the scratched area compared to the control group. The results depict that the use of CS-PVA hydrogel impregnated with the NO donor (SNAP) can be a promising material for promoting cell migration and subsequent accelerated healing of the chronic wounds in burns and diabetic patients.

Development of hydroxyapatite from eggshell waste and a chitosan-based composite: In vitro behavior of human osteoblast-like cell (Saos-2) cultures

Hydroxyapatite was successfully synthesized using eggshell waste as a raw material. Eggshell waste and orthophosphoric acid were co-precipitated for 2 h at an ambient temperature. The pH of the solution was adjusted to 10 using ammonium hydroxide. Then, 10-30 wt% of hydroxyapatite was loaded into the chitosan film. Scanning electron microscopy and energy dispersive analyses confirmed the morphological properties and dispersion. A thermogravimetric analysis showed a significant enhancement in the thermal stability of the composite. The existence of hydroxyapatite resulted in a higher thermal stability. Furthermore, atomic force microscopy was used to investigate the roughness of the surface. With the addition of hydroxyapatite, the roughness significantly increased. The swelling behavior of the composite was observed in phosphate buffer saline solution. The hydroxyapatite offered the inferiority on the swelling behavior. A preliminary investigation on the in vitro behavior of Saos-2 was also performed. The composite presented good cytotoxicity, and thus, excellent properties as a tissue engineering material.

Design of a 3D BMP-2-Delivering Tannylated PCL Scaffold and Its Anti-Oxidant, Anti-Inflammatory, and Osteogenic Effects In Vitro

In this study, a novel three-dimensional (3D) bone morphogenic protein-2 (BMP-2)-delivering tannylated polycaprolactone (PCL) (BMP-2/tannic acid (TA)/PCL) scaffold with anti-oxidant, anti-inflammatory, and osteogenic activities was fabricated via simple surface coating with TA, followed by the immobilization of BMP-2 on the TA-coated PCL scaffold. The BMP-2/TA/PCL scaffold showed controlled and sustained BMP-2 release. It effectively scavenged reactive oxygen species (ROS) in cells, and increased the proliferation of MC3T3-E1 cells pre-treated with hydrogen peroxide (H₂O₂). Additionally, the BMP-2/TA/PCL scaffold significantly suppressed the mRNA levels of pro-inflammatory cytokines, including matrix metalloproteinases-3 (MMP-3), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), in lipopolysaccharide (LPS)-induced MC3T3-E1 cells. Furthermore, it showed outstanding enhancement of the osteogenic activity of MC3T3-E1 cells through increased alkaline phosphatase (ALP) activity and calcium deposition. Our findings demonstrated that the BMP-2/TA/PCL scaffold plays an important role in scavenging ROS, suppressing inflammatory response, and enhancing the osteogenic differentiation of cells.