Detection of Plastic Nanoparticles in Aqueous Enviroment Based on Optical Manipulation in Combination with Raman Spectroscopy

Our planet's ecosystem is supersaturated with non-degradable plastic waste. The degradation of plastic items results in the generation of microplastic and nanoplastic particles. Detection of these kinds of particles still faces challenges due to the limitations of current detection methods and instruments, especially for what concerns the sub-10μm fraction. Herein, we report on a new optical method for optical aggregation that allows us to detect nanoplastics. We summarize recent progress in our experiments that use optical nanoimprinting of plasmonic metal nanoparticles to create the 'active' aggregates that can be used for Surface Enhanced Raman Spectroscopy (SERS) detection of biomolecules in microfluidic circuits and as plasmon-enhanced thermoplasmonic concentrators for nanoscale particulate matter such as nanoplastics. In both cases enhanced sensitivity is demonstrated, enabling the detection of nanoparticles/molecules of size/concentration orders of magnitude lower than what can be done by Raman spectroscopy or Raman Tweezers.