Poly(N-isopropylacrylamide) hydrogel: Effect of hydrophilicity on controlled release of ibuprofen at different pH

PNIPAM-MAPOSS Hybrid Hydrogels with Excellent Swelling Behavior and Enhanced Mechanical Performance: Preparation and Drug Release of 5-Fluorouracil

Poly(N-isopropylacrylamide) (PNIPAM) is a widely-studied polymers due to its excellent temperature sensitivity. PNIPAM-MAPOSS hybrid hydrogel, based on the introduction of acrylolsobutyl polyhedral oligomeric silsesquioxane (MAPOSS) into the PNIPAM matrix in the presence of polyethylene glycol, was prepared via radical polymerization. The modified hydrogels exhibited a thick, heterogeneous porous structure. PEG was used as a pore-forming agent to adjust the pore size. MAPOSS reduced the swelling ratios of gels, and decreased the LCST, causing the hydrogels to shrink at lower temperatures. However, its hydrophobicity helped to improve the temperature response rate. The incorporation of rigid MAPOSS into the polymer network greatly increased the compressive modulus of the hydrogel. It is worth noting that, by adjusting the amount of MAPOSS and PEG, the hydrogel could have both ideal mechanical properties and swelling behavior. In addition, hydrogel containing 8.33 wt % MAPOSS could achieve stable and sustained drug release. Thus, the prepared PNIPAM-MAPOSS hybrid hydrogel can serve as drug carrier for 5-fluorouracil and may have potential application in other biomedical fields.

Stimulus-responsive hydrogels: Theory, modern advances, and applications

Over the past century, hydrogels have emerged as effective materials for an immense variety of applications. The unique network structure of hydrogels enables very high levels of hydrophilicity and biocompatibility, while at the same time exhibiting the soft physical properties associated with living tissue, making them ideal biomaterials. Stimulus-responsive hydrogels have been especially impactful, allowing for unprecedented levels of control over material properties in response to external cues. This enhanced control has enabled groundbreaking advances in healthcare, allowing for more effective treatment of a vast array of diseases and improved approaches for tissue engineering and wound healing. In this extensive review, we identify and discuss the multitude of response modalities that have been developed, including temperature, pH, chemical, light, electro, and shear-sensitive hydrogels. We discuss the theoretical analysis of hydrogel properties and the mechanisms used to create these responses, highlighting both the pioneering and most recent work in all of these fields. Finally, we review the many current and proposed applications of these hydrogels in medicine and industry.