Calcitic Prisms of The Giant Seashell Pinna Nobilis Form Light Guide Arrays.

The shells of the Pinnidae family are based on a double layer of single-crystal-like calcitic prisms and inner aragonitic nacre, a structure known for its outstanding mechanical performance. However, on the posterior side, shells are missing the nacreous layer, which raises the question of whether there can be any functional role in giving up this mechanical performance. Here, it is demonstrated that the prismatic part of the Pinna nobilis shell exhibits unusual optical properties, whereby each prism acts as an individual optical fiber guiding the ambient light to the inner shell cavity by total internal reflection.

Interplay of surface interaction and magnetic torque in single-cell motion of magnetotactic bacteria in microfluidic confinement.

Swimming microorganisms often experience complex environments in their natural habitat. The same is true for microswimmers in envisioned biomedical applications. The simple aqueous conditions typically studied in the lab differ strongly from those found in these environments and often exclude the effects of small volume confinement or the influence that external fields have on their motion.

3D particle tracking using transport of intensity equation (TIE).

This article presents a simple and high-speed approach for tracking colloidal spheres in three dimensions. The method uses the curvature of the wavefront as determined by the transport of intensity equation (TIE) technique. Due to the fact that the TIE is applicable under partially coherent light, our technique is fully compatible with standard bright field microscopes, requiring no demanding environmental stability requirements or restrictions on the noise produced by related laser speckles.

Self-/Magnetic-Propelled Catalytic Nanomotors Based on a Janus SPION@PEG-Pt/PCL Hybrid Nanoarchitecture: Single-Particle versus Collective Motions.

In this paper, we synthesized superparamagnetic iron oxide nanoparticles (NPs) functionalized with (3-aminopropyl)triethoxysilane (FeO@APTES). The synthesized NPs were coated with succinic anhydride (FeO@COOH) in the next step. Half the surface of the NPs was shielded with wax microparticles via the Pickering emulsion technique, and the unshielded side was covered with poly(ethylene glycol) methyl ether.

3D imaging using scanning diffractometry.

Imaging of cells is a challenging problem as they do not appreciably change the intensity of the illuminating light. Interferometry-based methods to do this task suffer from high sensitivity to environmental vibrations. We introduce scanning diffractometry as a simple non-contact and vibration-immune methodology for quantitative phase imaging.

High-speed motility originates from cooperatively pushing and pulling flagella bundles in bilophotrichous bacteria.

Bacteria propel and change direction by rotating long, helical filaments, called flagella. The number of flagella, their arrangement on the cell body and their sense of rotation hypothetically determine the locomotion characteristics of a species. The movement of the most rapid microorganisms has in particular remained unexplored because of additional experimental limitations.

Surface proximity effect in sedimentation investigated by digital holographic microscopy.

In this paper, we measure the proximity effect of a flat wall on the sedimentation of colloidal particles by the use of digital holographic microscopy (DHM). DHM provides quantitative phase contrast and three-dimensional (3D) imaging in arbitrary time scales that are suitable to investigate various phenomena, including dynamic behavior of colloids. 3D information is obtained by post-processing of the recorded digital holograms through the angular spectrum propagation approach for numerical reconstruction.

Digital holographic microscopy for 3D surface characterization of polymeric nanocomposites.

The aim of this paper is to introduce digital holographic microscopy (DHM) as a non-contact, inexpensive, and non-abrasive method for 3D surface characterization of polymeric nanocomposites. A common-path and vibration-immune Mirau system with a microsphere-assisted arrangement is utilized to increase the lateral resolution of the images. The characterization is performed through the measurement of roughness parameters of the surfaces, which are derived from the recorded holograms.

Efficient in-depth trapping with an oil-immersion objective lens.

Maximum trapping efficiency in optical tweezers occurs close to the coverslip because spherical aberration owing to a mismatch in the refractive indices of the specimen (water) and the immersion oil dramatically decreases the trap efficiency as the trap depth increases. Measuring the axial trap efficiency at various tube lengths by use of an oil-immersion objective has shown that such an aberration can be balanced by another source of spherical aberration, leading to a shift in the position of the maximum efficiency in the Z direction. For a 1.