具有高电渗迁移率和亲水性通道壁特性的溶胶-凝胶改性聚二甲基硅氧烷微流控器件。

Sol-gel modified poly(dimethylsiloxane) microfluidic devices with high electroosmotic mobilities and hydrophilic channel wall characteristics.

作者信息

Roman Gregory T, Hlaus Tyler, Bass Kevin J, Seelhammer Todd G, Culbertson Christopher T

机构信息

Kansas State University, 111 Willard Hall, Manhattan, Kansas 66506, USA.

出版信息

Anal Chem. 2005 Mar 1;77(5):1414-22. doi: 10.1021/ac048811z.

DOI:10.1021/ac048811z

PMID:15732926

Abstract

Using a sol-gel method, we have fabricated poly(dimethylsiloxane) (PDMS) microchips with SiO2 particles homogeneously distributed within the PDMS polymer matrix. These particles are approximately 10 nm in diameter. To fabricate such devices, PDMS (Sylgard 184) was cast against SU-8 molds. After curing, the chips were carefully removed from the mold and sealed against flat, cured pieces of PDMS to form enclosed channel manifolds. These chips were then solvated in tetraethyl orthosilicate (TEOS), causing them to expand. Subsequently, the chips were placed in an aqueous solution containing 2.8% ethylamine and heated to form nanometer-sized SiO2 particles within the cross-linked PDMS polymer. The water contact angle for the PDMS-SiO2 chips was approximately 90.2 degrees compared to a water contact angle for Sylgard 184 of approximately 108.5 degrees . More importantly, the SiO2 modified PDMS chips showed no rhodamine B absorption after 4 h, indicating a substantially more hydrophilic and nonabsorptive surface than native PDMS. Initial electroosmotic mobilities (EOM) of (8.3+/-0.2)x10(-4) cm2/(V.s) (RSD=2.6% (RSD is relative standard deviation); n=10) were measured. This value was approximately twice that of native Sylgard 184 PDMS chips (4.21+/-0.09)x10(-4) cm2/(V.s) (RSD=2.2%; n=10) and 55% greater than glass chips (5.3+/-0.4)x10(-4) cm2/(V.s) (RSD=7.7%; n=5). After 60 days of dry storage, the EOM was (7.6+/-0.3)x10(-4) cm2/(V.s) (RSD=3.9%; n=3), a decrease of only 8% below that of the initially measured value. Separations performed on these devices generated 80,000-100,000 theoretical plates in 6-14 s for both tetramethylrhodamine succidimidyl ester and fluorescein-5-isothiocyanate derivatized amino acids. The separation distance was 3.5 cm. Plots of peak variance vs analyte migration times gave diffusion coefficients which indicate that the separation efficiencies are within 15% of the diffusion limit.

摘要

我们采用溶胶-凝胶法制备了聚二甲基硅氧烷（PDMS）微芯片，其中SiO₂颗粒均匀分布在PDMS聚合物基质中。这些颗粒直径约为10纳米。为了制造这种器件，将PDMS（Sylgard 184）浇铸在SU-8模具上。固化后，小心地将芯片从模具中取出，并与平坦的、已固化的PDMS片密封，以形成封闭的通道歧管。然后将这些芯片在原硅酸四乙酯（TEOS）中溶剂化，使其膨胀。随后，将芯片置于含有2.8%乙胺的水溶液中加热，以在交联的PDMS聚合物中形成纳米级SiO₂颗粒。PDMS-SiO₂芯片的水接触角约为90.2度，而Sylgard 184的水接触角约为108.5度。更重要的是，SiO₂改性的PDMS芯片在4小时后未显示罗丹明B吸收，表明其表面比天然PDMS具有更高的亲水性和非吸收性。测得初始电渗迁移率（EOM）为(8.3±0.2)×10⁻⁴ cm²/(V·s)（相对标准偏差RSD = 2.6%；n = 10）。该值约为天然Sylgard 184 PDMS芯片(4.21±0.09)×10⁻⁴ cm²/(V·s)（RSD = 2.2%；n = 10）的两倍，比玻璃芯片(5.3±0.4)×10⁻⁴ cm²/(V·s)（RSD = 7.7%；n = 5）高55%。干燥储存60天后，EOM为(7.6±0.3)×10⁻⁴ cm²/(V·s)（RSD = 3.9%；n = 3），比初始测量值仅降低了8%。在这些器件上进行的分离，对于四甲基罗丹明琥珀酰亚胺酯和异硫氰酸荧光素衍生的氨基酸，在6 - 14秒内产生了80,000 - 100,000理论塔板数。分离距离为3.5厘米。峰方差与分析物迁移时间的关系图给出的扩散系数表明，分离效率在扩散极限的15%以内。