A-409 Development of Zelas™ CP for suppressing nonspecific protein binding in advanced diagnostic and microfluidic applications

Abstract Background In recent years, the diagnostic market has expanded rapidly with the advancement in microfluidics devices for testing biomacromolecules such as DNA, RNA, and protein. Sensitivity is one of the crucial properties for developing the advanced microfluidics device to detect the extremely small amounts of target proteins in patient samples. However, the materials typically used in current devices such as COP, COC, and PMMA can cause the nonspecific binding of proteins on the surface that leads to a limitation in sensitivity. Also, these materials often require laborious assembly steps, including surface treatment with excimer and corona, or the use of adhesives However, both lead to additional time/cost for the assembly and pose potential risks of material degradation or contamination with adhesive eluents. Therefore, the development of advanced microfluidics chip with the enhanced sensitivity and high/multi functionality with complicated channel structures demands a material that suppresses protein binging on the surface while offering good processability. Methods (Protein binding on material surface) Injection-molded plate samples were prepared with Zelas™ CP, COP, and PMMA, respectively, and were incubated with human-derived fibrinogen solution (0.3 mg/ml) at 37 C for 2 hours. The absorbed protein on the surface was collected using a 5% SDS solution with sonification, and the amount was evaluated by uBCA assay. (Bondability for microfluidics chip assembly) The sets of substrates with channels and the lid were prepared by injection-molding of Zelas™ CP and COP, respectively. Thermo-welding at different temperatures (90 C – 120 C) was performed for the assembly to evaluate the bonding behavior and the damage to channel structure. Results (Protein binding on material surface) Zelas™ CP showed the least amount of absorbed protein on the surface among the tested materials (COP and PMMA), attributed to its unique surface with a micro-phase separation structure featuring polar/non-polar domains, similar to those found on biological surfaces such as cell membrane, DNA, and protein. (Bondability for microfluidics chip assembly) Thermo-welding at different temperatures revealed that 100 C is sufficient to assemble the substrate with the lid made from Zelas™ CP. On the other hand, COP material either didn’t adhere or caused damage to the channel structure due to its high glass transition temperature (102 C). The results indicated that Zelas™ CP doesn’t require any pre-treatment by corona or excimer, or the use of adhesives, enabling high-throughput and cost reduction in manufacturing. Also, the workable temperature range of Zelas™ CP is customizable, as CP 211 demonstrated an even lower temperature for assembly, allowing access to the microfluidics channel with a complex channel structure. Conclusion Zelas™ CP exhibits suppressed protein adsorption on the surface and excellent processability, making it ideal for advanced microfluidics applications requiring enhanced sensitivity or high/multi functionality with complex channel structures. The material also possesses other characteristics such as low autofluorescence, which is important for suppressing detection noise and widening the detection window in diagnostic applications.