Authors: C. Lo Presti
Affilation: Merck Serono, Italy
Pages: 141 - 142
Keywords: polymer chemistry, biomaterials, biopharma
Continuous advances in polymer chemistry are enabling the synthesis of novel responsive biomaterials. This class of biomaterials are polymers able to undergo significant changes in their properties in response to external stimuli. Depending on their chemical architecture, responsive polymers can reversibly or irreversibly vary characteristics such as mechanical properties, appearance, structure, viscosity, volume, electrical conductivity, colour, fluorescence, opacity, shape and, ultimately, function. Some examples of nanostructured responsive materials for the biopharma industry will be shown. pH responsive hydrogels based on poly(N-2-HydroxyEthyl)-DL-Aspartamide (PHEA-MA) have been synthesized without the use of any toxic reagent via gamma-irradiation. The nanoporosity of hydrogels could be tailored by controlling irradiation parameters, such as total absorbed dose and dose rate, leading to “on-off” release of encapsulated proteins depending on the external pH. The ability of hydrogels to protect the encapsulated protein from harsh conditions, such as highly acidic pH, crowding and high temperatures has also been assessed. A “synthetic virus” has been produced that is able to enter cells, escape from the endocytic pathway, and efficiently deliver actives within cells without perturbing their metabolic activity. This biomimetic nanovector is based on the self-assembly of amphiphilic block copolymers into nanometer-sized vesicles (or polymersomes). The cellular-uptake kinetics can be regulated by controlling the surface chemistry, the polymersome size, and the polymersome surface topology. This latter can be controlled by the extent of polymer phase separation on the outer shell of the polymersome. Finally, “soft” nanocomposites will be presented as candidates for biosensors, based on polyaniline (PANI) nanoparticles finely dispersed into biocompatible hydrogels, able to emit light and conduct electricity depending on pH.