Continuous Sensing of blood by dark-field microscopy and surface-enhanced Raman Spectroscopy

A.-I. Henry, B. Sharma, L.B. Sagle, R.P. Van Duyne
Northwestern university, US

Keywords: chemical sensing, SERS, dark-field microscopy

Summary:

Surface-enhanced Raman spectroscopy (SERS) is a rapid, label-free technique with multiplexing capabilities, making it very relevant for the sensitive real-time detection for biomedical applications,, . Demonstration of in vivo glucose detection with unprecedented sensitivity (micromolar to picomolar concentration sensitivity) in a rat model has been made recently in our group. We have developed a combined SERS-active microfluidic substrate that has been integrated with a SERS imaging system for the detection of biomarkers. The SERS substrate has been functionalized with optimized surface chemistries (mixed self-assembled monolayers) for the capture of small molecules and bacteria. Microfluidic channels on top of the SERS-active surface allow for flowing blood, which is distributed over the substrate (see Figure). SERS imaging uses a line focus parallel to the channels, which accounts for measuring the SERS signal continuously and visualize the SERS activity across the microfluidic channel with the imaging capability of this system.