Nanorefrigerative tweezers for optofluidic manipulation

Plasmonic optical tweezers with the ability to manipulate nano-sized particles or molecules that are beyond the diffraction limit have been developed rapidly in recent years. However, plasmonic heat generation always limits its applications in capturing particles or biomacromolecules that are vulnerable to high temperatures. Here, we propose nanorefrigerative tweezers based on a single refrigerative nanocrystal, which can form a nanometer-sized cold-spot via anti-Stokes fluorescence. Numerical simulations are performed to compute the temperature and velocity fields. The results show that thermo-osmosis and thermophoresis play major roles in nanoparticle manipulation, while natural convection in the nanoscale is negligible. This tweezing scheme not only offers a sub-diffraction-limit way to manipulate nano-objects but also avoids possible thermal damage to the trapped targets. Therefore, it will potentially become a powerful tool in biomedical and biosensing research studies. Published under an exclusive license by AIP Publishing.

Automated summary

Plasmonic optical tweezers have been rapidly developed to manipulate nano-sized particles or molecules. However, plasmonic heat generation limits its applications. In this study, nanorefrigerative tweezers based on a single refrigerative nanocrystal are proposed, which can create a cold spot through anti-Stokes fluorescence. Numerical simulations show that thermo-osmosis and thermophoresis play major roles in nanoparticle manipulation. This tweezing scheme has the potential to become a powerful tool in biomedical and biosensing research.