Optical tweezers that rely on laser irradiation to capture and manipulate nanoparticles have provided powerful tools for biological and biochemistry studies. However, the existence of optical diffraction-limit and the thermal damage caused by high laser power hinder the wider application of optical tweezers in the biological field. For the past decade, the emergence of optothermal tweezers has solved the above problems to a certain extent, while the auxiliary agents used in optothermal tweezers still limit their biocompatibility. Here, we report a kind of nanotweezers based on the sign transformation of the thermophoresis coefficient of colloidal particles in low-temperature environment. Using a self-made microfluidic refrigerator to reduce the ambient temperature to around 0 °C in the microfluidic cell, we can control a single nanoparticle at lower laser power without adding additional agent solute in the solution. This novel optical tweezering scheme has provided a new path for the manipulation of inorganic nanoparticles as well as biological particles.

Surface plasmonic resonance (SPR) has been a corner stone for approaching single molecular detection due to its high-sensitivity capability and simple detection mechanism, and has brought major advancements in biomedicine and life science technology. Over decades, the successful integration of SPR with versatile techniques has been demonstrated. However, several crucial limitations have hindered this technique for practical applications, such as long detection time and low overall sensitivity. This review aims to provide a comprehensive summary of existing approaches in enhancing the performance of SPR sensors based on “passive” and “active” methods. Firstly, passive enhancement is discussed from a material aspect, including signal amplification tags and modifications of conventional substrates. Then, the focus is on the most popular active enhancement methods including electrokinetic, optical, magnetic, and acoustic manipulations that are summarized with highlights on their advantageous features and ability to concentrate target molecules at the detection sites. Lastly, prospects and future development directions for developing SPR sensing towards a more practical, single molecular detection technique in the next generation are discussed. This review hopes to inspire researchers’ interests in developing SPR-related technology with more innovative and influential ideas.