Piccin Evandro, Coltro Wendell Karlos Tomazelli, Fracassi da Silva José Alberto, Neto Salvador Claro, Mazo Luiz Henrique, Carrilho Emanuel
Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil.
J Chromatogr A. 2007 Nov 30;1173(1-2):151-8. doi: 10.1016/j.chroma.2007.09.081. Epub 2007 Oct 10.
This paper presents the use of elastomeric polyurethane (PU), derived from castor oil (CO) biosource, as a new material for fabrication of microfluidic devices by rapid prototyping. Including the irreversible sealing step, PU microchips were fabricated in less than 1h by casting PU resin directly on the positive high-relief molds fabricated by standard photolithography and nickel electrodeposition. Physical characterization of microchannels was performed by scanning electron microscopy (SEM) and profilometry. Polymer surface was characterized using contact angle measurements and the results showed that the hydrophilicity of the PU surface increases after oxygen plasma treatment. The polymer surface demonstrated the capability of generating an electroosmotic flow (EOF) of 2.6 x 10(-4)cm(2)V(-1)s(-1) at pH 7 in the cathode direction, which was characterized by current monitoring method at different pH values. The compatibility of PU with a wide range of solvents and electrolytes was tested by determining its degree of swelling over a 24h period of contact. The performance of microfluidic systems fabricated using this new material was evaluated by fabricating miniaturized capillary electrophoresis systems. Epinephrine and l-DOPA, as model analytes, were separated in aqueous solutions and detected with end-channel amperometric detection.
本文介绍了一种源自蓖麻油生物源的弹性体聚氨酯（PU）作为通过快速成型制造微流控器件的新材料的应用。包括不可逆密封步骤在内，通过将PU树脂直接浇铸在通过标准光刻和镍电沉积制造的正性高浮雕模具上，在不到1小时的时间内制造出了PU微芯片。通过扫描电子显微镜（SEM）和轮廓测量法对微通道进行了物理表征。使用接触角测量对聚合物表面进行了表征，结果表明，氧等离子体处理后PU表面的亲水性增加。聚合物表面在pH值为7时，在阴极方向产生了2.6×10⁻⁴cm²V⁻¹s⁻¹的电渗流（EOF），这是通过在不同pH值下的电流监测方法表征的。通过在24小时接触期内测定其溶胀程度，测试了PU与多种溶剂和电解质的兼容性。通过制造小型化毛细管电泳系统，评估了使用这种新材料制造的微流控系统的性能。作为模型分析物的肾上腺素和左旋多巴在水溶液中被分离，并用通道末端安培检测法进行检测。
