Super-High-Resolution Densitometry by Optical Trapping of a Single-Molecularly Imprinted Polymer Particle for Subsingle Molecule Detection.

In this study, for the first time, we have shown that the single nano-/microparticle trapping ability of optical tweezers combined with the high selectivity of molecularly imprinted polymers (MIPs) provides an indispensable molecular-level instrument for chemical sciences. Trapping a single MIP inside a solution and analyzing its Brownian motion allow for real-time determination of its target molecule [trimipramine (TMP) in our case] content. This method is also utilized to precisely measure TMP concentration in the bulk solution.

Hexagonal arrays of gold triangles as plasmonic tweezers.

We present theoretical and experimental studies of the plasmonic properties of hexagonal arrays of gold triangles, fabricated by angle-resolved nanosphere lithography method. Our numerical and experimental results both show that a change in the angle of gold deposition affects the size and the distance between the triangles, leading to a controlled shift in their absorption and scattering spectra. We calculate the force exerted on the polystyrene particles of 650 nm radii numerically while passing above the hexagonal arrays.

Atorvastatin treatment softens human red blood cells: an optical tweezers study.

Optical tweezers are proven indispensable single-cell micro-manipulation and mechanical phenotyping tools. In this study, we have used optical tweezers for measuring the viscoelastic properties of human red blood cells (RBCs). Comparison of the viscoelastic features of the healthy fresh and atorvastatin treated cells revealed that the drug softens the cells.

Fluorescent quantification of size and lamellarity of membrane nanotubes.

Membrane nanotubes, ubiquitous in cellular systems, adopt a spectrum of curvatures and shapes that are dictated by their intrinsic physical characteristics as well as their interactions with the local cellular environment. A high bending flexibility is needed in the crowded cytoplasm where tubes often need to bend significantly in the axial direction at sub-micron length scales. We find the stiffness of spontaneously formed membrane nanotubes by measuring the persistence length of reconstituted membrane nanotubes freely suspended in solution and imaged by fluorescence microscopy.