Near‐Field Optical Tweezers for Chemistry and Biology

Abstract

Near‐field optical tweezer techniques have been essential for the development for manipulation and identification of micro‐ and nanoparticles (NPs) in lab‐on‐a‐chip systems. Optical waveguide, which has been exploited as a fascinating manipulation approach, provides valuable insights into the biology of the specific type of cells and potential for enhanced Raman spectroscopy. Specific waveguides and its own structures in near‐field optical techniques can be used to trap, transport, sort, levitate, and deform a micro‐ or NP in colloid chemistry and pharmaceutical biology. Given the precise manipulation and trapping stiffness with low light power, a diverse range of micro/nanostructured optical fiber, silicon‐on‐insulator resonator, photonic crystal cavity, and plasmonic waveguide have been proposed in many theoretical models and experimental observations, including polystyrene bead, silica bead, metal particle, erythrocyte, virus, and DNA. Considering the optical pressure fundamental, fabrication process, and structure categorization, this review describes recent mainstream developments and future perspectives of near‐field optical tweezers for chemical and biological applications.