Use of poly(glycerol sebacate) as an alternative to poly(dimethylsiloxane) as a platform for making micro-fluidic channels

Poly(dimethylsiloxane) (PDMS) has been used extensively for making microfluidic devices because of several favorable features: optical transparency, bio-compatibility, easy moldability and its inertness towards most materials. However, PDMS is non-biodegradable and swells when in contact with most solvents. It is also an expensive material. As an alternative, here we have presented the application of poly(glycerol sebacate) (PGS), a thermoset elastomer for fabrication of microchannels. PGS is synthesized <i>via</i> the condensation reaction of sebacic acid, a non-edible vegetable oil, and glycerol which results in a flexible, biocompatible and optically transparent bio-elastomer; its Young's modulus has been varied over a wide range: 0.125-1.4 MPa. We have shown that controlled etching with an aqueous solution of NaOH yields microchannels of a variety of shapes, sizes and complexities: straight and spiral channels and ones with patterned surfaces of the channel wall and depth. The PGS surface shows hydrophobicity initially but turns hydrophilic over time, with minimal swelling effect, thereby highlighting its suitability for both aqueous and non-aqueous media. With acidic and neutral buffers, PGS shows negligible leaching, thereby suggesting usability of microfluidic channels under physiological conditions. PGS channels were used also in multiple layers with a membrane in-between, to explore controlled transport of drug and nutrient molecules and to determine possible bioanalytical applications.