A low-cost, rapid deposition method for "smart" films: applications in mammalian cell release.

The "smart" polymer poly (N-isopropyl acrylamide), or pNIPAM, has been studied for bioengineering applications. The polymer's abrupt change in hydrophobicity near physiologic temperatures makes it ideal for use as a substrate in many applications, including protein separation and prevention of biofouling. To tether pNIPAM, many techniques such as plasma deposition, have been utilized, but most are expensive and require long equipment calibration or fabrication periods. Recently, a novel method for codepositing this smart polymer with a sol-gel, tetraethyl orthosilicate (TEOS), was developed. In this work, we adapt this technique for applications in mammalian cell attachment/detachment. In addition, we compare the effects of the pNIPAM/TEOS ratio to functionality using surface analysis techniques (XPS and contact angles). We found the optimal ratio to be 0.35 wt % pNIPAM/TEOS. Cell detachment from these substrates indicate that they would be ideal for applications that do not require intact cell sheets, such as biofouling prevention and protein separation, as this technique is a simple and affordable technique for pNIPAM deposition.