Surface-Enhanced Raman Spectroscopic Probing in Digital Microfluidics through a Microspray Hole

We report a novel approach for surface-enhanced Raman spectroscopy (SERS) detection in digital microfluidics (DMF). This is made possible by a microspray hole (mu SH) that uses an electrostatic spray (ESTAS) for sample transfer from inside the chip to an external SERS substrate. To realize this, a new ESTAS-compatible stationary SERS substrate was developed and characterized for sensitive and reproducible SERS measurements. In a proof-of-concept study, we successfully applied the approach to detect various analyte molecules using the DMF chip and achieved micro-molar detection limits. Moreover, this technique was exemplarily employed to study an organic reaction occurring in the DMF device, providing vibrational spectroscopic data.

Automated summary

We present a new approach for surface-enhanced Raman spectroscopy (SERS) detection in digital microfluidics (DMF) using a microspray hole (mu SH) that utilizes electrostatic spray (ESTAS) for sample transfer. A novel ESTAS-compatible stationary SERS substrate was developed and characterized for sensitive and reproducible SERS measurements. Proof-of-concept experiments showed successful detection of various analyte molecules with micro-molar detection limits using the DMF chip and provided vibrational spectroscopic data of an organic reaction occurring in the DMF device.