Polímeros termorresponsivos: principais características do hidrogel e aplicações biomédicas

Abstract

The need to improve efficiency in drug administration has resulted in incentives in scientific research for the development of new materials with biomedical applications that can act in vivo, allowing the release of drugs in specific locations, improving their use, and reducing the loss of principle active. Polymers processed in the form of hydrogels are highlighted due to their excellent biocompatibility with human tissues and organs, non-toxicity, biodegradability, similarity to extracellular matrices in terms of structure and properties, as well as their ability to respond to external stimuli. Among the possible stimuli, hydrogels that respond to changes in temperature, the so-called thermosensitive hydrogels, stand out. These polymers can change their solubility through temperature variation, that is, they are materials capable of gelling without any additional external factor. Some of the thermosensitive polymers that can be mentioned are poly (N-isopropylacrylamide) (PNIPAm), Poly (acrylic acid) (PAA), Poly (N-vinylcaprolactam) (PNVCL), Poloxamer 407 (P407), among others. These hydrogels have presented interesting applications in several areas, with an emphasis on biomedical uses, being used as vehicles for the controlled release of drugs. Many of these polymers can be combined with other polymers or inorganic molecules, enhancing their intrinsic characteristics, which could lead to an increase in the drug's controlled release capability and an adjustment in the sol-gel transition temperature. It is noteworthy that thermosensitive hydrogels can also have applications beyond the biomedical area, as in the case of making smart equipment, but this use is still not widespread and is an expanding area for its use. This work consists of a literature review on the use of thermosensitive hydrogels, where some of the main polymers used for their synthesis and their best-known applications were described.