Stimuli‐Responsive Polymeric Systems for Biomedical Applications

Abstract

Smart polymeric‐based devices and surfaces that reversibly alter their physico‐chemical characteristics in response to their environment are the center of many studies related to the development of materials and concepts in a broad‐range of biomedical fields. Although the initial interests were more focused in systems for the delivery of therapeutic molecules, other applications have been raised in topics ranging from actuators to biomaterials for tissue engineering and regenerative medicine. The general aspects of the different types of stimuli that can be used to modulate the response are reviewed mainly for the case of hydrogels and surfaces, based on natural‐origin or biodegradable macromolecules. Thermosensitive or light responsive surfaces that can modulate cell adhesion or protein adsorption are addressed as well as less conventional smart surfaces, such as substrates onto which biomineralization may be triggered. Injectable liquids that turn to gels by the action of heating (sol‐gel thermo‐reversible hydrogels) or by changing pH or the ionic milieu (bioinspired self‐assembling systems) may find great applicability as temporary scaffolds in non invasive procedures to deliver drugs or cells to particular places in the body. Examples of systems that recognize independently or simultaneously more than one stimulus will also be presented. Besides the typical response to temperature and pH, recent developments on materials that react to biochemical stimuli, including specific enzymes, antibodies or cells, are also highlighted.

Biopolymer-based Stimuli-Responsive Polymeric Systems for Functional Finishing of Textiles

“…Hydrogels responsive to temperature and pH have been the most widely studied systems since these two factors have a physiological significance. Versatile dual responsive hydrogels have been reported mainly for biomedical applications and a number of reviews coming up in this area in recent times address the latest developments (Kumar et al, 2007;Mano, 2008;Kopecek & Yang, 2007). However, due to the need for biocompatibility and biodegradability, biopolymer based hydrogels are currently of great interest.…”

Whole-organ engineering with natural extracellular materials

“…Traditionally, 'smart materials' include materials such as piezoelectric sensors, shape memory alloys and polymer-responsive gels, which can respond to environmental fluctuations through physical or chemical changes. Smart polymers respond to changes in pH, ionic strength, chemical species, enzyme-substrate interactions, magnetic fields, temperature, electric fields, mechanical stimulation, as well as ultrasound irradiation [58,59]. These materials exploit responsiveness for a triggered release.…”

Functionalization of cotton with poly-NiPAAm/chitosan microgel: Part II. Stimuli-responsive liquid management properties

“…Since temperature and pH have a physiological significance, versatile dual responsive hydrogels have been reported mainly for biomedical applications (Kopecek and Yang 2007;Kumar et al 2007;Mano 2008). Simultaneously, an increasing amount of research is being done on functional finishing of textile materials by incorporating stimuliresponsive polymeric systems, which resulted in publishing two extensive review papers (Crespy and Rossi 2007;Liu and Hu 2005).…”