Research PaperLabel-free SERS analysis of proteins and exosomes with large-scale substrates from recordable compact disks

- Inexpensive and large-scale SERS-active materials were easily fabricated from regular CD-R and DVD-R disks.
- The nanostructured silver-coated materials were characterized and key parameters in the Raman enhancement were studied.
- The Raman fingerprint of hemoglobin and exosomes was obtained in label-free conditions with the developed SERS substrates.
- Potential lab-on-a-disk biosensing devices for Raman analysis in point-of-care settings are suggested.

A central aspect to fully reach the biosensing scope of plasmonics beyond the research environment is its implementation in inexpensive and homogeneous functional nanostructured materials that can be manufactured in a large-scale fashion. Herein, we study the capabilities of consumer-grade compact disk technology for label-free SERS analysis of complex biological targets. Substrates from regular recordable disks (CD-R and DVD-R) coated with silver exhibit significant Raman enhancement. The magnitude of this enhancement depends on the nanostructure on the polycarbonate substrate, the silver thickness, and the excitation wavelength. The Raman fingerprint of hemoglobin and exosome samples were experimentally obtained in label-free conditions, which demonstrates the biosensing potential of this approach and suggests prospective developments towards fully exploiting the bioanalytical capabilities of SERS in point-of-care settings.