Enhanced optical trapping of ZrO₂@TiO₂ photonic force probe with broadened solvent compatibility

Abstract

Optical trapping and manipulating nanoparticles are essential tools for interrogating biomedicine at the limits of space and time. Typically, silica or polystyrene microspheres are used as photonic force probes. However, adapting those probes to organic solvents is an ongoing challenge due to the limited solvent compatibility and low refractive index mismatch. Here we report on the optical force enhancement and solvent compatibility that utilizes ZrO2@TiO2 core-shell nanoparticles. We experimentally demonstrate that the 450-nm-diameter ZrO2@TiO2 core-shell nanoparticles achieve the lateral and axial trap stiffness up to 0.45 pN µm−1 mW−1 and 0.43 pN µm−1 mW−1 in water, showing more than fivefold and ninefold improvement on the ordinary SiO2 particle of the same size. In addition, ZrO2@TiO2 core-shell nanoparticles can realize stable three-dimensional trapping in both polyethylene glycol and glucose solutions. This optical trapping enhancement property, coupled with solvent compatibility, expands the range of feasible optical trapping experiments and will pave the way toward more advanced biological applications.

Optically levitated micro gyroscopes with an MHz rotational vaterite rotor

“…Compared to multiaxis combined inertial sensing technology, this scheme can greatly reduce the complexity of the system and is expected to become a new generation of high-precision measuring elements. Although the sensitivity and instability of the gyroscopes are not ideal at present, the performance of the gyroscopes can be greatly improved by laser cooling, customized levitated rotors, and enhanced optical trap stiffness [40][41][42] , thus providing new sensing technology for inertial navigation. These experiments are implemented in a free space optical system; however, the presented optically levitated gyroscope has the potential to be realized on a chip [43][44][45] , and hybrid methods can be used to calculate the optical force and torque in an integrated system 46,47 .…”

Detection and photothermal inactivation of Gram-positive and Gram-negative bloodstream bacteria using photonic crystal biosensor and plasmonic core–shell

“…To experimentally fabricate FeO@AuBiS 2 core–shell structures, begin by synthesizing FeO nanoparticles through a method such as co-precipitation or thermal decomposition. 76 Next, prepare the AuBiS 2 shell by adding gold and bismuth precursors to a sulfur-containing solution under controlled conditions to facilitate shell formation around the FeO nanoparticles. 68 Utilize techniques like solvothermal or sonochemical methods for the core–shell assembly, ensuring proper shell growth and uniform coverage.…”

Optical manipulation of anisotropic spherical shell particles in a dual-beam trap

“…Recently, anisotropic spherical shell particles hold great promise for applications in optical manipulation [36], biomedicine [37] and materials science [38]. For example, in colloidal systems, anisotropic thin films are commonly utilized to decrease the van der Waals interactions between particles and the solvent, thereby enhancing the optical trapping performance of particles [39,40]. Besides, certain anisotropic materials can serve as anti-reflection coatings and efficiently encapsulate microparticles, reducing the scattering forces and further improving the optical trapping efficiency [41].…”