Patterning multiplex protein microarrays in a single microfluidic channel.

The development of versatile biofunctional surfaces is a fundamental prerequisite in designing Lab on a Chip (LOC) devices for applications in biosensing interfaces and microbioreactors. The current paper presents a rapid combinatorial approach to create multiplex protein patterns in a single microfluidic channel. This approach consists of coupling microcontact printing with microfluidic patterning, where microcontact printing is employed for silanization using (3-Aminopropyl) triethoxysilane (APTES), followed by microfluidic patterning of multiple antibodies. As a result, the biomolecules of choice could be covalently attached to the microchannel surface, thus creating a durable and highly resistant functional interface. Moreover, the experimental procedure was designed to create a microfluidic platform that maintains functionality at high flow rates. The functionalized surfaces were characterized using X-ray photoelectron spectroscopy (XPS) and monitored with fluorescence microscopy at each step of functionalization. To illustrate the possibility of patterning multiple biomolecules along the cross section of a single microfluidic channel, microarrays of five different primary antibodies were patterned onto a single channel and their functionality was evaluated accordingly through a multiplex immunoassay using secondary antibodies specific to each patterned primary antibody. The resulting patterns remained stable at shear stresses of up to 50 dyn/cm(2). The overall findings suggest that the developed multiplex functional interface on a single channel can successfully lead to highly resistant multiplex functional surfaces for high throughput biological assays.