Hybrid Thermo-Responsive Polymer Systems and Their Biomedical Applications

Abstract

Targeted and controlled drug delivery employing "smart materials" is a widely investigated field, within which stimuli-responsive polymers, particularly those which are thermo-responsive, have received considerable attention. Thermo-responsive polymers have facilitated the formulation of in situ gel forming systems which undergo a sol-gel transition at physiological body temperature, and have revolutionized the fields of tissue engineering, cell encapsulation, and controlled, sustained delivery of both drugs and genes. However, the use of single thermo-responsive polymers in the creation of these systems has posed numerous problems in terms of physico-mechanical properties, such as poor mechanical strength, high critical gelation concentrations (CGC) resulting in increased production costs and solutions that are too viscous, toxicity, as well as gelation temperatures that are incompatible with physiological body temperatures. Hybridization of these thermo-responsive polymers with other polymers has therefore been employed, resulting in the creation of tailor-made drug delivery systems that have optimal gelation temperatures and concentrations, ideal viscosities and improved gel strengths. This article reviews various thermo-responsive polymers that have been employed in the formulation of thermo-gelling systems. Special attention has been given to the hybridization of each of these polymers, the resulting systems that have been created, and their biomedical applications.

Exploration of Bioengineered Scaffolds Composed of Thermo-Responsive Polymers for Drug Delivery in Wound Healing

“…Nevertheless, these polymers may not present the same biodegradable performance as the natural, as well as exhibit lower biocompatibility [ 53 , 54 ]. Remarkably, the limitations exhibited by natural and synthetic polymers can be overcome by their blending, obtaining a hybrid polymer [ 55 , 56 , 57 ].…”

Bioengineered Scaffolds for Thermo-responsive Drug Delivery in Wound Healing

“…Nevertheless, these polymers may not present the same biodegradable performance as the natural, as well as exhibit lower biocompatibility [45,46]. Remarkably, the limitations exhibited by natural and synthetic polymers can be overcome by their blending, obtaining a hybrid polymer [47][48][49].…”

“…Scaffolds provide templates for tissue regeneration and physical support for cell growth [78]. These can be made of artificial or natural thermo-responsive polymers, which can condition the different biomedical applications due to their effect on the functional attributes [47,79,80]. This type of smart polymers has been widely used as a scaffold in non-invasive methods for different tissues, such as skin and heart [81,82].…”

Thermoresponsive Nanogels Based on Different Polymeric Moieties for Biomedical Applications

“…Hydrogels are three-dimensional cross-linked structures based on natural or synthetic polymers. Hydrogels can be produced in different physical forms, such as slabs, macroparticles, nanoparticles and films [ 1 , 2 ]. Promising properties, such as high water content, biocompatibility and degradability, make hydrogels very useful for biomedical applications [ 3 , 4 , 5 ].…”