样品分配是在聚合物微流体平台上实现生物测定数字化的关键步骤。然而,有效的液体填充到微孔和长期亲水性仍然是聚合物微流体装置的挑战,阻碍诊断和细胞培养研究的适用性。为了克服这一点,提出了一种使用环烯烃共聚物(COC)微流体芯片生产永久性超亲水3维微孔的方法。COC基材使用UV处理氧化,然后超声喷涂聚乙烯醇溶液,提供高纵横比微观特征的均匀和长期涂层。涂覆的COC表面在与疏水性压敏粘合剂粘合之前被UV固化以驱动选择性填充到孔中。使用此方法获得的表面亲水性保持不变(水接触角为9°)长达6个月,并且对改性表面进行了物理表征(接触角和表面能,形态学,微观特征和粗糙度的完整性),化学成分(FTIR,拉曼光谱)和涂层稳定性(pH,温度,时间)。建立改性表面在生物应用中的可行性,PVA涂层的COC微流控芯片进行DNA传感(CMV的数字LAMP检测)测试,通过蛋白质吸附和细胞培养研究(细胞粘附,生存能力,和代谢活动)。肾和乳腺细胞在该改性表面上的测试期间(7天)保持存活,涂层不影响蛋白质含量,培养细胞的形态或质量。超声波喷涂系统,用0.25%PVA涂覆15个循环,UV氧化后电流为0.12A,将COC(天然疏水)的表面能从22.04增加到112.89mJ/m2,并将微孔中的填充效率从40%(天然未处理的COC)提高到94%,而不会干扰表面的生物相容性,证明是有效的,用于诊断和细胞生长应用的高通量和可扩展的微流控表面处理方法。
Sample partitioning is a crucial step towards digitization of biological assays on polymer microfluidic platforms. However, effective liquid filling into microwells and long-term hydrophilicity remain a challenge in polymeric microfluidic devices, impeding the applicability in diagnostic and cell culture studies. To overcome this, a method to produce permanent superhydrophilic 3-dimensional microwells using cyclic olefin copolymer (COC) microfluidic chips is presented. The COC substrate is oxidized using UV treatment followed by ultrasonic spray coating of polyvinyl alcohol solution, offering uniform and long-term coating of high-aspect ratio microfeatures. The coated COC surfaces are UV-cured before bonding with a hydrophobic pressure-sensitive adhesive to drive selective filling into the wells. The surface hydrophilicity achieved using this method remains unchanged (water contact angle of 9°) for up to 6 months and the modified surface is characterized for physical (contact angle & surface energy, morphology, integrity of microfeatures and roughness), chemical composition (FTIR, Raman spectroscopy) and coating stability (pH, temperature, time). To establish the feasibility of the modified surface in biological applications, PVA-coated COC microfluidic chips are tested for DNA sensing (digital LAMP detection of CMV), and biocompatibility through protein adsorption and cell culture studies (cell adhesion, viability, and metabolic activity). Kidney and breast cells remained viable for the duration of testing (7 days) on this modified surface, and the coating did not affect the protein content, morphology or quality of the cultured cells. The ultrasonic spray coated system, coating with 0.25 % PVA for 15 cycles with 0.12 A current after UV oxidation, increased the surface energy of the COC (naturally hydrophobic) from 22.04 to 112.89 mJ/m2 and improved the filling efficiency from 40 % (native untreated COC) to 94 % in the microwells without interfering with the biocompatibility of the surface, proving to be an efficient, high-throughput and scalable method of microfluidic surface treatment for diagnostic and cell growth applications.