Fluidic adaptive lenses with an adjustable focal length over a wide range were demonstrated in this letter. The focal length adjustment was achieved by changing the shape of the fluidic lens without any mechanical moving parts. The shortest focal length demonstrated in such devices is 41 mm, which corresponds to a large numerical aperture of 0.24 and a small F number of 2.05. The highest resolution measured using a positive standard is 25.39 lp/mm in this fluidic adaptive lens.

Fluorescent colloidal particles, fabricated by depositing a thin gold film on one side of the particle, show intensity fluctuation (blinking) under an optical microscope because of their rotational Brownian motion. Interactions between molecules immobilized on the surfaces of the particle and the solid substrate restrict the rotation of the particle, thus modulating the intensity fluctuations. Because we can obtain the time-dependent rotational angle from the fluorescent intensity, we can use the intensity signals to investigate the weak interactions between unlabeled molecules by analyzing the angular distribution of the particle. To the best of our knowledge, this is the first demonstration of an optical measurement of the rotations of nanoparticles and the first attempt at using such a technique to study molecular interactions.

We elucidate the major mechanism of microparticle removal in the megasonic cleaning process through the direct visualization experiments. It is revealed that particles sitting on solids are removed by adjacent microbubbles that oscillate near the substrates and exert interfacial and pressure gradient forces on the particles. Other pressure and streaming effects are shown to be too weak to detach the particles.

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In this study, the chemo-drug doxorubicin (DOX) was successfully encapsulated in PEG–biotin conjugated porphyrin SANs (DOX@TPP–PEG–biotin) and had synergistic effects after PDT action.