(436e) Achieving Both Antifouling and Selective Adsorption in a PDMS-Based Microfluidic Device By Using a Functional Surface-Segregating Zwitterionic Copolymer Additive

Nonspecific protein adsorption has been a persistent challenge in the use of poly (dimethyl siloxane) (PDMS)-based microfluidic devices due to PDMS’s hydrophobicity. This issue has led to the development of various post-processing techniques to make the surface antifouling, such as plasma treatment and surface grafting of hydrophilic polymers. However, these approaches often complicate the manufacturing process of the devices and can adversely affect critical properties such as mechanical properties and transparency. Many also have limited stability, with the surface becoming hydrophobic again within days. Additionally, for many applications, it is of interest to selectively adsorb only specific analytes while preventing the adhesion of others, specifically for use in protein capture for diagnostics, biochemical assays, and cell capture for organ-on-a-chip models with drug screening. Achieving both of these simultaneously is particularly challenging. To address this challenge, we have synthesized a surface segregating copolymer additive that self-assembles to create a hydrophilic, antifouling zwitterionic surface interspersed with functionalizable groups when blended with PDMS during the manufacture of microfluidic devices, with no additional processing steps needed. Using this approach, we have been able to decrease the nonspecific adsorption of Bovine Serum Albumin (BSA) on PDMS surfaces by at least 95%. We have also shown that we can utilize the functionality of this polymer additive to attach desired functional groups to mediate the adsorption of specific analytes. We expect this novel method for simultaneous fouling prevention and surface functionalization of PDMS surfaces to enable the development of better-performing biomicrofluidic devices as well as other silicone-based biomaterials such as catheters and implants.