Advances in inorganic nanoparticles trapping stiffness measurement: A promising tool for energy and environmental study

Optical tweezers system has emerged as an efficient tool to manipulate tiny particles in a non-invasive way. Trapping stiffness, as an essential parameter of an optical potential well, represents the trapping stability. Additionally, trapping inorganic nanoparticles such as metallic nanoparticles or other functionalized inorganic nanoparticles is important due to their properties of good stability, high conductivity, tolerable toxicity, etc., which makes it an ideal detection strategy for bio-sensing, force calculation, and determination of particle and environmental properties. However, the trapping stiffness measurement (TSM) methods of inorganic nanoparticles have rarely been analyzed and summarized. Here, in this review, the principle and methods of TSM are analyzed. We also systematically summarize the progress in acquiring inorganic particles trapping stiffness and its promising applications. In addition, we provide prospects of the energy and environment applications of optical tweezering technique and TSM. Finally, the challenges and future directions of achieving the nanoparticles trapping stiffness are discussed.