Vanillin/fungal-derived carboxy methyl chitosan/polyvinyl alcohol hydrogels prepared by freeze-thawing for wound dressing applications.

In this study, we developed hydrogels using polyvinyl alcohol (PVA), vanillin (V), and a fungus-derived carboxymethyl chitosan (FC) using a freeze-thaw-based method. These hydrogels were strengthened by bonding, including Schiff's base bonding between V and FC and hydrogen bonding between PVA, FC, and V. The physiological properties of these PFCV hydrogels were characterized by FTIR, TGA, compressive mechanical testing, and rheology and water contact angle measurements. FTIR spectra confirmed the effective integration of FC and V into the PVA network. TGA results showed that FC and V enhanced the thermal stability of PFCV hydrogels. Mechanical tests showed increasing the amount of V reduced mechanical properties but did not alter the elastic character of hydrogels. SEM images displayed a well-interconnected porous structure with excellent swelling capacity. In addition, we examined biological properties using cell-based in vitro studies and performed antibacterial assessments to assess suitability for potential wound dressing applications. Prestoblue™ and live/dead cell analysis strongly supported skin fibroblast attachment and viability, DPPH assays indicated substantial antioxidant activity, and PFCV hydrogels showed enhanced antibacterial effects against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). In summary, incorporating V and FC into PVA hydrogels appears to be attractive for wound dressing applications.

Novel, Biosynthesis of Palladium Nanoparticles using Strychnos Potatorum Polysaccharide as a Green sustainable approach; and their effective Catalytic Hydrogenation of 4-Nitrophenol.

In the current study, we successfully used strychnos potatorum polysaccharide through autoclaving to synthesize palladium nanoparticles in a green, sustainable process. These polysaccharide act as a stabilizing, capping, and reducing agent. It also used various analytical characterizations, including UV-Visible spectroscopy, FT-IR spectroscopy, X-Ray diffraction (XRD), Scanning electron microscopy (FE-SEM), EDAX, and X-ray photoelectron spectroscopy (XPS), TEM and gel permeation chromatography (GPC) are used to analyze biosynthesized pallidum nanoparticles (PdNPs). The surface plasmon resonance (SPR) band at 276 nm and UV-visible spectroscopy revealed the presence of the generated PdNPs. The XRD data show that PdNPs have crystalline behavior and a pristine face-centered cubic (FCC) structure. The PdNPs were successfully developed by catalytic reduction of 4-nitrophenol (4-NP). The catalytic activity and reusability of the environmentally friendly PdNPs catalyst were demonstrated by achieving a remarkable transformation of 95 % nitrophenol to 4-aminophenol after five cycles. The reaction rate constant (k) for the degradation of 4-nitrophenol (4-NP) using SP-PdNPs as a catalyst is 0.1201 min-1 and R2 0.9867, with a normalized rate constant of (Knor = K/m) of 7.206 s-1 mM-1. These findings provide fundamental knowledge of the catalytic process governing the hydrogenation of p-nitrophenol, which will help designers of effective catalysts. An innovative and affordable technique for creating PdNPs that are environmentally acceptable and can be utilized as effective catalysts in environmental applications is the use of strychnos potatorum gum polysaccharide. The green-synthesized PdNPs can be used for pollutant remediation, including pharmaceutical, domestic, heavy metal, industrial, and pesticide pollutants.

ROS-generating, pH-responsive and highly tunable reduced graphene oxide-embedded microbeads showing intrinsic anticancer properties and multi-drug co-delivery capacity for combination cancer therapy.

The development of effective carriers enabling combination cancer therapy is of practical importance due to its potential to enhance the effectiveness of cancer treatment. However, most of the reported carriers are monofunctional in nature. The carriers that can be applied to concomitantly mediate multiple treatment modalities are highly deficient. This study fills this gap by reporting the design and fabrication of ROS-generating carbohydrate-based pH-responsive beads with intrinsic anticancer therapy and multidrug co-delivery capacity for combination cancer therapy. Sodium alginate (SA) microspheres and reduced graphene oxide (rGO)-embedded chitosan (CS) beads are developed via emulsion-templated ionic gelation for a combination therapy involving co-delivery of curcumin (CUR) and 5-fluororacil (5-FU). Drug-encapsulated microbeads are characterized by FTIR, DSC, TGA, XRD, and SEM. 5-FU and CUR-encapsulated microbeads are subjected to in vitro drug release studies at pH 6.8 and 1.2 at 37 °C. Various release kinetic parameters are evaluated. The results show that the Korsmeyer-Peppas model and non-Fickian release kinetics are best suited. The microspheres and microbeads are found to effectively act against MCF7 cells and show intrinsic anticancer capacity. These results indicate the promising performance of our beads in mediating combination drug therapy to improve the effectiveness of cancer treatment.

Strychnos Potatorum L. Seed Polysaccharide-Based Stimuli-Responsive Hydrogels and Their Silver Nanocomposites for the Controlled Release of Chemotherapeutics and Antimicrobial Applications.

Natural Strychnos potatorum L. (SPL) polysaccharide-based dual-responsive semi-IPN-type (SPL-DMA) hydrogels have been fabricated using dimethylaminoethyl methacrylate by simple free radical polymerization. Furthermore, a facial and eco-friendly method has been developed for the green synthesis of silver nanoparticles on SPL-DMA hydrogel templates (SPL-DMA-Ag) using an aqueous leaf extract of Carissa spinarum (as a bioreducing agent). SPL-DMA and SPL-DMA-Ag were characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and evaluated network parameters. 5-Fluorouracil and doxorubicin were successfully encapsulated, and in vitro drug release studies were performed at pH values of 1.2 and 7.4 and at 25 and 37 °C. To understand the drug release mechanism of SPL-DMA hydrogels, various kinetic parameters were calculated. Biocompatibility and anticancer activities of SPL-DMA hydrogels were proved by an antioxidant activity study and in vitro cell viability studies against HeLa and 3T3-L1 cell lines. SPL-DMA-Ag hydrogels were used for antibacterial application.

Tragacanth gum-based multifunctional hydrogels and green synthesis of their silver nanocomposites for drug delivery and inactivation of multidrug resistant bacteria.

This study investigated natural polymer-based stimuli-responsive hydrogels (TGIAVE) and their silver nanocomposites (TGIAVE-Ag). The hydrogels were composed of tragacanth gum, N-isopropyl acrylamide, and 2-(vinlyoxy) ethanol and were prepared via simple redox polymerization using N,N'-methylene-bis-acrylamide as a crosslinker and potassium persulfate as an initiator. The TGIAVE-Ag were synthesized via a green method involving an aqueous extract of Terminalia bellirica seeds. Structural, thermal, crystallinity, morphology, and size characteristics of the TGIAVE and TGIAVE-Ag were investigated by FTIR, UV-Vis, XRD, DSC, SEM, EDS, DLS, and TEM. To understand the physicochemical interaction and diffusion characteristics of TGIAVEs, network parameters such as zero-order, first-order, Hixson-Crowell, Higuchi, and Korsmeyer-Peppas values were calculated by assessing swelling data. TGIAVE hydrogels at pH 1.2 and 7.4 and temperatures of 25 and 37 °C may be used for time-dependent controlled release of 5-fluorouracil, an anticancer drug, TGIAVE-Ag may be applied for the inactivation of multidrug resistant (MDR) bacteria.

Nanoparticles of pH-Responsive, PEG-Doxorubicin Conjugates: Interaction with an in Vitro Model of Lung Adenocarcinoma and Their Direct Formulation in Propellant-Based Portable Inhalers.

Pulmonary administration of polymer drug conjugates is of great potential clinical significance for treating lung cancer as such regimen significantly increases local drug concentrations while decreases systemic and local side effects. In this work, we demonstrate that nanoparticles prepared with methoxypoly(ethylene glycol) (mPEG)-doxorubicin (DOX) conjugates (mPEG-DOX) that have a pH-sensitive imine bond (Schiff base) can at the same time work as efficient carriers for DOX to kill cancer cells and also as a strategy to directly formulate nanoparticles in propellant-based inhalers. Nanoparticles prepared by precipitation in water had a diameter in the range between 100 and 120 nm. We investigated the effects of molecular weight (MW) of mPEG (1K, 2K, and 5K Da) on the in vitro release kinetics, cellular internalization, and cytotoxicity on in vitro model of lung adenocarcinoma and aerosol characters. It is observed that the DOX released from mPEG-DOX nanoparticles was significantly accelerated in acidic environment, pH 5.5 (endosomal/lysosomal pH) in comparison with pH 7.4 (physiological pH), as designed. Release of DOX from mPEG1K-DOX nanoparticles was significantly greater than those from mPEG2K and mPEG5K counterparts. In vitro cytotoxicity of nanoparticles followed the sequence of mPEG1K-DOX > free DOX > mPEG2K-DOX ≫ mPEG5K-DOX, a trend closely following their rate and extent of cellular internalization. mPEG-DOX nanoparticles with mPEG1K and mPEG2K were directly dispersed in hydrofluoroalkane (HFA), while a trace of ethanol was required to disperse mPEG5K-DOX nanoparticles in HFA. These pMDI formulations with high physical stability in HFAs display superior aerosol characteristics conducive to deep lung deposition. The fine particle fractions of these formulations ranged from 40-60%, higher than those of commercial products. Such formulations prepared from nanoparticles of pH-sensitive PEG-drug conjugates may also be envisioned to be extended to formulate other hydrophobic drugs for local delivery with propellant-based inhalers to other pulmonary disorders, thus broadening the impact of the proposed strategy.

Phosphate crosslinked pectin based dual responsive hydrogel networks and nanocomposites: Development, swelling dynamics and drug release characteristics.

Potential dual responsive hydrogel networks (PPAD) are fabricated from pectin, poly((2-dimethylamino)ethyl methacrylate)) and phosphate crosslinker bis[2-methacryloyloxy] ethyl phosphate (BMEP) by a simple free radical polymerization. These hydrogel networks are successfully utilized for encapsulation of an anti-cancer drug, 5-fluorouracil (5-FU) and also employed as versatile platforms for production of silver nanoparticles. Fabricated hydrogel networks and silver nanocomposites were characterized by FTIR, SEM, EDX, TEM, DLS, DSC, TGA and XRD. Different polymer network parameters such as MC¯, χ, ξ and υe and diffusion constant (D) were evaluated to assess the drug release profile. The 5FU loaded PPAD hydrogels were used to perform in vitro release studies in both gastric and intestinal conditions of GIT (pH 1.2 & pH 7.4) at two different temperatures (25 and 37°C). On the other hand various kinetic models (zero, first, Higuchi & Koresmeyer-Peppas) have also been employed to fit drug release profile. In addition, the antibacterial activity of PPAD silver nanocomposites were tested against four bacterial species Escherichia coli (-ve), Klebsiella pneumoniae (-ve), Bacillus cereus (+ve) and Staphylococcus aereus (+ve) using zone of inhibition test.

Synthesis of dual responsive carbohydrate polymer based IPN microbeads for controlled release of anti-HIV drug.

The present study aims at preparation of dual responsive interpenetrating polymer network hydrogel microbeads from sodium alginate and functionally modified guar gum. Guar gum was modified by graft copolymerization using N-vinylcaprolactam, the maximum % grafting 123.2, obtained at different optimized conditions. The graft copolymer was blended with sodium alginate to form hydrogel microbeads by emulsion crosslinking method using glutaraldehyde as crosslinker. Zidovudine, an anti-HIV drug was encapsulated with 68% encapsulation efficiency. Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance spectroscopy, scanning electron microscopy, differential scanning calorimetry and X-ray diffraction studies justified the grafting reaction, structure, morphology and polymer-drug interactions, respectively. Swelling studies ascertained that microbeads were potentially sensitive to both pH and temperature. In vitro release studies were investigated in pH 1.2 and 7.4, the release time enhanced up to 34h in pH 7.4 at 37°C.

Biodegradable sodium alginate-based semi-interpenetrating polymer network hydrogels for antibacterial application.

A series of biodegradable, semi-interpenetrating polymer network (semi-IPN) hydrogels were synthesized from a combination of carbohydrate polymer and sodium alginate (NaAlg) with acrylamide and dimethyl aminoethyl methacrylate, and crosslinked with N,N-methylenebisacrylamide via radical redox polymerization. The cytocompatibility of the hydrogels with respect to their monomers and semi-IPN hydrogels was evaluated in vitro using cultures of mouse fibroblast cell lines. This study allowed the entrapment of silver nanoparticles (NPs) into semi-IPN hydrogel networks by the in situ reduction of Ag(+) ions using NaBH4 as a reducing agent. UV-visible spectroscopy confirmed the formation of silver NPs in the semi-IPN hydrogel matrix. The formation of silver NPs was also confirmed from a themogravimetric analysis weight loss difference between hydrogel and silver nanocomposite as 32%. The morphology and structure of the AgNPs present in the hydrogel networks were examined by scanning electron microscopy. Transmission electron microscopy revealed silver NPs with a size of ∼5 nm. The silver nanocomposite hydrogel exhibited good antibacterial activity against both gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria. These results suggest that the hydrogel can be applied as wound dressings and for water purification purposes.