Optical Tweezers in Raman Spectroscopy

Optical tweezers and Raman spectroscopy (OTRS) are two powerful techniques widely used in the field of biophysics for studying the structural and mechanical properties of biological systems at the single-molecule level. By using laser beams focused on microscopic targets, optical tweezers can capture and manipulate biomolecules and cells precisely. On the other hand, Raman spectroscopy provides information about the chemical composition and conformation of a substrate in a non-invasive manner. Incorporating Raman spectroscopy with optical tweezers can allow molecular information to be obtained while controlled mechanical forces can be applied, leading to a better understanding of biological systems’ mechanical properties and structural dynamics. A review of optical tweezers combined with Raman spectroscopy is presented in this chapter. The working principle OTRS setup is discussed in detail, along with the various design configurations that have evolved over the years. Among other practical considerations, the potential for photodamage to biomolecules subjected to excitation and trapping is discussed, along with essential instrumentation requirements needed to realize the experimental setup. Various applications of OTRS are discussed along with ways to enhance the Raman signal, such as by using SERS.