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Biopolymers are essential building blocks that constitute cells and tissues with well‐defined molecular structures and diverse biological functions. Their three‐dimensional (3D) complex architectures are used to analyze, control, and mimic various cells and their ensembles. However, the free‐form and high‐resolution structuring of various biopolymers remain challenging because their structural and rheological control depend critically on their polymeric types at the submicron scale. Here, direct 3D writing of intact biopolymers is demonstrated using a systemic combination of nanoscale confinement, evaporation, and solidification of a biopolymer‐containing solution. A femtoliter solution is confined in an ultra‐shallow liquid interface between a fine‐tuned nanopipette and a chosen substrate surface to achieve directional growth of biopolymer nanowires via solvent‐exclusive evaporation and concurrent solution supply. The evaporation‐dependent printing is biopolymer type‐independent, therefore, the 3D motor‐operated precise nanopipette positioning allows in situ printing of nucleic acids, polysaccharides, and proteins with submicron resolution. By controlling concentrations and molecular weights, several different biopolymers are reproducibly patterned with desired size and geometry, and their 3D architectures are biologically active in various solvents with no structural deformation. Notably, protein‐based nanowire patterns exhibit pin‐point localization of spatiotemporal biofunctions, including target recognition and catalytic peroxidation, indicating their application potential in organ‐on‐chips and micro‐tissue engineering. [ABSTRACT FROM AUTHOR]

Quantifying humidity has long been an unavoidable task in science, industry, and society. Recent developments of nanoscience and technology that deal with ultrasmall droplets have aroused interest in microscopic moisture. Utilization of nanomaterials has been emerging as a promising strategy to miniaturize hygrometers for high‐sensitive, ultrasmall‐area sensing. However, a lack of high‐precision, on‐demand position control of sensing nanomaterials makes it difficult to explore spatial distribution of humidity at the micro‐ and nanoscale. Here, a scanning probe hygrometry (SPH) is developed that enables not only micro/nanoresolution but also scalable spatial mapping of humidity distribution. The SPH is realized with an unprecedented scanning nanowire probe interferometer (NPI) that is produced by direct 3D nanoprinting of a moisture‐sensitive polymer on a tapered optical fiber. Notably, the interferometric response of the NPI probe in ultrasmall areas quantitatively depends on humidity, arising from its refractive index change and volumetric swelling. By scanning the NPI probe and reading out the interferometric signals, multiscale spatial mapping of humidity distribution with versatile scanning steps from ≈102 nm to a few mm is demonstrated. The NPI is expected to provide a new nanoscale metrology that can answer fundamental questions about evaporation‐related science and engineering. [ABSTRACT FROM AUTHOR]

Phase contrast imaging study and computer simulations of microvoids located in solid materials of complex structure have been reported. Images of microvoids arise as interference fringes due to coherent scattering of synchrotron radiation (SR) in matter. In the first part of this work, the simulation of the experimental image of a single tubular microvoid in a SiC crystal to illustrate the advantages and limitations of one‐dimensional (1D) phase‐contrast method and to discuss the approach to 2D objects has been performed. In the second part, a new iterative method for the variable wave function of radiation is employed to examine the applicability of the phase‐contrast method for an array of tubules. The latter method has been shown to be sufficiently accurate to be useful when a number of tubules along the beam is limited. Finally, the interference patterns generated by waves passing through a phantom dentin specimen have been calculated and analyzed. It has been demonstrated that both methods have extensive possibilities to determine the period in the lattice of tubules, even in the presence of some disorder. [ABSTRACT FROM AUTHOR]

It has been generally accepted that any reaction between micropipes in silicon carbide (SiC) crystals requires a direct contact of the micropipes. We propose a new model of contact-free reactions that are realized through the emission and absorption of full-core dislocations by micropipes. This model can explain the correlated reduction in micropipe radii in the samples with low micropipe densities which has been observed in synchrotron radiation (SR) phase contrast images supported by computer simulations. We provide a theoretical description of a contact-free reaction between two parallel micropipes. [ABSTRACT FROM AUTHOR]