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Objective: We aimed to evaluate cytocompatibility of hyaluronic acid (HA) and gelatin (Gela) conjugation with phenolic groups (Phs) via enzyme-mediated crosslinking. Phenolic moieties were substituted on the backbone of HA (HA-Ph) and Gela (Gela-Ph) and subsequently were subjected for horseradish peroxidase crosslinking in the presence of H 2 O 2 as an electron donor to create a stable hybrid microenvironment for cellular behavior and cartilage tissue engineering., Results: Successful synthesis of biopolymers confirmed by NRM and UV-Vis spectrophotometry. The physical characteristic of hydrogels including mechanical properties and water contact angle of hydrogels enhanced with addition of Gela-Ph in HA-based hydrogel. The Gela-Ph showed longest gelation time and highest degradation rate. The cellular studies showed cells did not attach to HA-Ph hydrogel. While, proper cell attachment and proliferation observed on blend hydrogel surface compared with the neat hydrogels which interpret by the existence of cell-adhesive motifs of utilized Gela-Ph in this hydrogel. The encapsulated cells in HA-Ph hydrogel were spheroid and just maintained their viability. Hydrogels containing Gela-Ph, the cells were spindle shape with high degrees of cytoplasmic extension. Overall, the results suggest that hybrid biomimetic hydrogel can provide a superior biological microenvironment for chondrocytes in 3D cartilage tissue engineering., (© 2022. The Author(s).)

Current hyaluronic acid-based hydrogels often cause cytotoxicity to encapsulated cells and lack the adhesive property required for effective biomedical and tissue engineering applications. Provision of the cell-adhesive surface is an important requirement to improve its biocompatibility. An aqueous solution of hyaluronic acid possessing phenolic hydroxyl (HA-Ph) moieties is gellable via a horseradish peroxidase (HRP)-catalyzed oxidative cross-linking reaction. This study evaluates the effect of different degrees of cross-linked Ph moieties on cellular adhesiveness and proliferation on the resultant enzymatically cross-linked HA-Ph hydrogels. Mechanical characterization demonstrated that the compression force of engineered hydrogels could be tuned in the range of 0.05-35 N by changing conjugated Ph moieties in the precursor formulation. The water contact angle and water content show hydrophobicity of hydrogels increased with increasing content of cross-linked Ph groups. The seeded mouse embryo fibroblast-like cell line and human cervical cancer cell line, on the HA-Ph hydrogel, proved cell attachment and spreading with a high content of cross-linked Ph groups. The HA-Ph with a higher degree of Ph moieties shows the maximum degree of cell adhesion, spreading, and proliferation which presents this hydrogel as a suitable biomaterial for biomedical and tissue engineering applications., (© 2020 Wiley Periodicals LLC.)

One of the most effective approaches for treatment of chronic rhinosinusitis is the use of hydrogel scaffolds with the sustained release of a given required drug. With this in mind, first, we synthesized and characterized poly (lactide-co-glycolide) (PLGA) micro and nano particles loaded with dexamethasone (DEX). We observed a 7-day release of DEX from nanoparticles, while the microparticles showed a 22-day release profile. Due to their slower rate of release, the PLGA microparticles loaded with DEX (PLGADEX microparticles) were specifically chosen for this study. As a second step, chitosan/polyvinylpyrrolidone (PVP) based hydrogels were prepared in various weight ratios and the PLGADEX microparticles were optimized in their structure based on variable gelation times. The morphological studies showed PLGADEX microparticles homogenously dispersed in the hydrogels. Moreover, the effect of weight ratio in the presence and absence of optimum percentage of PLGADEX microparticles was studied. The resultant hydrogels demonstrated a range of advantages, including good mechanical strength, porous morphology, amorphous structure, high swelling ratio, controlled biodegradability rate, and antibacterial activity. Additionally, a cytotoxicity analysis confirmed that the hydrogel scaffolds do not have adverse effects on the cells; our release studies in the hydrogel with the highest PVP content also showed 80% release after 30 days. Based on these results we were able to predict and control some of the mechanical properties, including the microstructure of the scaffolds, as well as the drug release, by optimizing the polymers - microparticle concentration, plus their resulting interactions. This optimized hydrogel can become part of a suitable alternative for treatment of allergic rhinitis and chronic sinusitis., (Copyright © 2020 Elsevier B.V. All rights reserved.)