Search

The synthetic route presented for acrylate-modified hyaluronic acid (HA-A-BEA) offers a simple and efficient process, reducing reaction time and purification steps while retaining biocompatibility. This study demonstrates the ability of HA-A-BEA to form tunable hydrogels via versatile techniques suitable for biomedical applications. [ABSTRACT FROM AUTHOR]

Frequent removal and reapplication of wound dressings can cause mechanical disruption to the healing process and significant physical discomfort for patients. In response to this challenge, a dynamic covalent hydrogel has been developed to advance wound care strategies. This system comprises aldehyde functionalized chondroitin sulfate (CS-CHO) and thiolated hyaluronic acid (HA-SH), with the distinct ability to form in situ via thiol–aldehyde addition and dissolve on-demand via the thiol–hemithioacetal exchange reaction. Although rarely reported, the dynamic covalent reaction of thiol–aldehyde addition holds great promise for the preparation of dynamic hydrogels due to its rapid reaction kinetics and easy reversible dissociation. The thiol–aldehyde addition chemistry provides the hydrogel system with highly desirable characteristics of rapid gelation (within seconds), self-healing, and on-demand dissolution (within 30 min). The mechanical and dissolution properties of the hydrogel can be easily tuned by utilizing CS-CHO materials of different aldehyde functional group contents. The chemical structure, rheology, self-healing, swelling profile, degradation rate, and cell biocompatibility of the hydrogels are characterized. The hydrogel possesses excellent biocompatibility and proves to be significant in promoting cell proliferation in vitro when compared to a commercial hydrogel (HyStem® Cell Culture Scaffold Kit). This study introduces the simple fabrication of a new dynamic hydrogel system that can serve as an ideal platform for biomedical applications, particularly in wound care treatments as an on-demand dissolvable wound dressing. [ABSTRACT FROM AUTHOR]

Copper‐catalyzed reversible deactivation radical polymerization (RDRP) of N,N‐dimethylacrylamide (DMA) has been a significant challenge, particularly in aqueous environments, such as low yields, broad molecular weight distribution (MWD), and ill‐controlled molecular weights (MWs). In this work, we report the synthesis of well‐defined poly(N,N‐dimethylacrylamide) (PDMA) via a facile Cu(0)‐mediated RDRP in water. The results show that, unlike other acrylamide monomers, for DMA with abundant tertiary amide groups, the sufficient deactivation—the key to realizing control in copper‐catalyzed RDRP—cannot be simply fulfilled by just increasing the amount of deactivator (i.e., CuII species). The enhanced deactivation must be appropriately determined by also considering and selecting other reaction parameters. It is demonstrated that the use of methyl 2‐chloropropionate (MCP) as initiator and copper(II) chloride (CuCl2) as the additional catalyst is an effective combination to simultaneously enhance the deactivation control and facilitate the chain growth in aqueous Cu(0)‐mediated RDRP of DMA. This strategy successfully achieved the fast and well‐controlled synthesis of PDMAs with high monomer conversion, narrow MWDs, and a range of predefined MWs, and the well‐controlled in situ chain extensions. [ABSTRACT FROM AUTHOR]

A kind of commercial hybrid carrageenan (HC)/agarose composite sponge containing κ‐, μ‐, ι‐, and ν‐carrageenan, which could turn into hydrogel and release carrageenan at human body temperature was fabricated for immune stimulation and modulation. Release behavior demonstrated that the hybrid carrageenan contained sponge was mechanically stable and could release carrageenan constantly. RT‐PCR and ELISA experiments showed that the leaching liquor of the sponge could stimulate RAW264.7 from M0 state to a polarized state by secreting more anti‐inflammatory factor IL‐10 than pro‐inflammatory ones, such as, IL‐6 and TNF‐α. Transwell experiments also indicated that the leaching liquor could promote the proliferation of NIH‐3T3 by stimulating RAW264.7 of M0 state after 7 days. Results of particle size and intracellular concentration analyses suggested that the released carrageenan might enter into the cellular interior of RAW264.7 in the form of microgels or protein complexes. The sponge would be a promising candidate for skin wound dressing. [ABSTRACT FROM AUTHOR]