Stimuli‐Responsive Thin Coatings Using Elastin‐Like Polymers for Biomedical Applications

Abstract

AbstractSmart thin coatings using a recombinant elastin‐like polymer (ELP) containing the cell attachment sequence arginine–glycine–(aspartic acid) (RGD) are fabricated for the first time through simple deposition of the ELP dissolved in aqueous‐based solutions. The biopolymer is produced and characterized using electrophoresis and mass spectroscopy. The temperature and pH responsiveness are assessed by aggregate size measurements and differential scanning calorimetry. The deposition of the studied ELP onto chitosan is followed in situ with a quartz‐crystal microbalance with dissipation monitoring (QCM‐D). Contact angle measurements are performed at room temperature and at 50 °C, showing reversible changes from a moderate hydrophobic behavior to an extremely wettable surface. AFM analysis performed at room temperature reveals a smooth surface and no organized structure. At 50 °C, the surface presents spherical nanometer‐sized structures of collapsed biopolymer chains. Such results suggest that the ELP chains, when collapsed, aggregate into micelle‐like structures at the surface of the substrate, increasing its water affinity. Cell adhesion tests on the developed coatings are conducted using a SaOS‐2 cell line. Enhanced cell adhesion could be observed in the H‐RGD6‐coated surfaces, as compared with the original chitosan monolayer. An intermediate behavior is found in chitosan coated with the corresponding ELP without the RGD sequence. Therefore, the developed films have great potential as biomimetic coatings of biomaterials for different biomedical applications, including tissue engineering and controlled delivery of bioactive agents. Their thermo‐responsive behavior can also be exploited for tunable cell adhesion and controlled protein adsorption.