Poly(N-isopropylacrylamide)-Based Thermoresponsive Composite Hydrogels for Biomedical Applications

Abstract

Poly(N-isopropylacrylamide) (PNIPAM)-based thermosensitive hydrogels demonstrate great potential in biomedical applications. However, they have inherent drawbacks such as low mechanical strength, limited drug loading capacity and low biodegradability. Formulating PNIPAM with other functional components to form composited hydrogels is an effective strategy to make up for these deficiencies, which can greatly benefit their practical applications. This review seeks to provide a comprehensive observation about the PNIPAM-based composite hydrogels for biomedical applications so as to guide related research. It covers the general principles from the materials choice to the hybridization strategies as well as the performance improvement by focusing on several application areas including drug delivery, tissue engineering and wound dressing. The most effective strategies include incorporation of functional inorganic nanoparticles or self-assembled structures to give composite hydrogels and linking PNIPAM with other polymer blocks of unique properties to produce copolymeric hydrogels, which can improve the properties of the hydrogels by enhancing the mechanical strength, giving higher biocompatibility and biodegradability, introducing multi-stimuli responsibility, enabling higher drug loading capacity as well as controlled release. These aspects will be of great help for promoting the development of PNIPAM-based composite materials for biomedical applications.

Effect of Iron-Oxide Nanoparticles Impregnated Bacterial Cellulose on Overall Properties of Alginate/Casein Hydrogels: Potential Injectable Biomaterial for Wound Healing Applications

“…Biomaterials at present are used in a variety of forms such as hydrogels, sponges, scaffolds, electrospun mesh and so on [ 3 ]. Out of all these, hydrogels have emerged as the most promising candidate for use in biomedical applications such as targeted drug delivery and tissue regeneration due to favorable biocompatibility, biodegradability and low cytotoxicity [ 4 , 5 ]. Hydrogels are essentially porous, with matching physical and mechanical properties to the extracellular matrix (ECM), allowing for the transport of oxygen and moisture, and movement of nutrients, payloads such as drugs, genes and other biomolecules [ 6 ].…”

Thermoresponsive Polymer Gating System on Mesoporous Shells of Silica Particles Serving as Smart Nanocontainers

“…There have been numerous examples of nanocarriers composed of thermoresponsive polymers that can be applied for releasing active substances using either temperature-triggered or other types of mechanisms [23][24][25][26][27]. One may observe also a growing interest concerning mechanized silica nanoparticles that utilize supramolecular nanovalves responding to external stimuli for controlled release of encapsulated substances [28][29][30][31][32].…”

Retention of poly(N‐isopropylacrylamide) thin films on polycarbonate via polymer interdiffusion

“…The retention of pNIPAAm, which is highly soluble in water at room temperature, on PC was determined by thoroughly rinsing the processed samples with room temperature water. All the retained pNIPAAm films (3–50 nm) exhibited thermoresponsive behaviors, verified by water contact angles above and below the lower critical solution temperature (LCST) of pNIPAAm (i.e., 32°C 21 ). The thermoresponsive behavior was more pronounced for a thicker retained pNIPAAm film, which resulted when the underlying PC layer was pretreated with Air Plasma (AP) for 5–10 min.…”

“…One of the polymers that has attracted great interests in recent years to be retained on a support is thermoresponsive poly( N ‐isopropylacrylamide) (pNIPAAm). The retained pNIPAAm has wide applications ranging from cell therapy and cell sheet engineering to oil–water separation, antifouling and drug delivery 16–21 . A common approach for retaining pNIPAAm is grafting pNIPAAm as brushes to a surface, 2–422 ; such an approach could be expensive and laborious 2–5 .…”