Polymer gradient surfaces for biomedical applications

Biological systems interact with artificial polymeric materials in a complex, multistage, and iterative process of sensing and response. The biological response at the cellular level to polymeric substrates has been studied at great length. However, this is often done on individual samples with a homogeneous feature. This results in experiments which are limited only to samples that the investigator can imagine — leaving potentially interesting samples or sample combinations hidden from use. Subtle variations in surface properties can have a drastic impact on cell response, and therefore a considered and careful approach must be employed in surface design and fabrication. Following the example set by combinatorial chemistry and high-throughput screening (HTS) applied to drug discovery by the pharmaceutical industry in the 1990s, researchers are increasingly turning to similar methodologies in biomaterial design. This involves creating high content samples for exploring the full sample space, usually taking the form of a highly multiplexed array platform, or a continuous variation of a single material property as a gradient. Creating such dense sample formats presents a series of unique challenges in both their fabrication and implementation. In the case of surface modification for biomedical applications, platforms must be created which offer broad variations in surface properties, and they must also be designed in such a way as to allow meaningful interpretation of often complex responses