In-Situ Synthesis of 3-D Nanostructures Within a Microfluidic Device and Their Applications As SERS Substrates

In-situ synthesis of 3-D nanostructures within a microfluidic device and their applications as SERS Substrates

 Joseph Parisi, Liang Su, Yixin Liu, Yu Lei

Department of Chemical, Materials, & Biomolecular Engineering, University of Connecticut, 191 Auditorium Road, Unit 3222, Storrs, Connecticut 06269

            Microfluidic devices have been used in many different applications and have continued to display their ability to shrink large scale experiments into small scale devices.  In this report, a microfluidic device with integrated novel silver nanoparticle (Ag NPs) decorated nanowall structures was fabricated via in-situ electrodeposition of Cu-core/C-sheath nanowalls, followed by a facile in-channel silver galvanic replacement reaction method at room temperature. These nanostructures are fabricated in a fraction of the time compared to similar CVD and hydrothermal structures and require much less reagents and complicated fabrication steps.  The integrated microfluidic devices with Ag NPs decorated nanowalls, serving as a highly active Raman substrate, was then applied for in-channel surface-enhanced Raman scattering (SERS) sensing. Single molecule detection is obtained using model compounds, and the detection of water contaminants is also presented. Because preparation of the active SERS substrate and subsequent finger-print SERS detection is completed within a microfluidic device, the developed method opens a new venue to integrate active SERS substrate within microfluidic channels and provides an excellent microfluidic SERS sensor platform for ultrasensitive and selective chemical and biological sensing.