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Cellulose nanocrystals (CNCs) are an environmentally friendly natural material, consisting of rod‐like crystalline nanoparticles, called whiskers, or nanocrystalline cellulose. The derivation of different natural sources, aligned to their biocompatibility, biodegradability, and versatility, make them a class of fascinating materials with widespread industrial use. In addition, the cellulose species possess intriguing physicochemical and mechanical properties. This paper provides an overview of recent progress in the area of cellulosic nanocomposites, along with details of their structure and liquid crystalline behavior as nematic and cholesteric lyotropic materials. Guidance is subsequently provided for the physicochemical analysis of these materials, including X‐ray diffraction, transmission electron microscopy, optical evaluation, thermogravimetric analysis, and differential scanning calorimetry. Additionally, the functional chemical and physical properties of CNCs are correlated to the resulting nanotoxicity in in vitro and in vivo assays. This review points to relevant concerns, such as sources for the synthesis of CNCs, the nanomaterial size, and the surface chemistry, that must be overcome in order to attain safe use of CNC‐based nanomaterials. The challenging perspectives on the ongoing research are presented in order to explore the technological and industrial perspectives on the use of CNC for the generation of cost‐effective advanced nanomaterials based on cellulosic fibers. [ABSTRACT FROM AUTHOR]

Microfluidic devices that generate stable concentration gradients are efficient instruments for automated calibration for analytical and bioanalytical systems. However, little attention has been paid to the development of reusable microfluidic concentration gradient generators, which can be useful for a range of species through mathematical characterization. In this work, we develop a microfluidic device based on three steps of serial dilution that were able to generate nonlinear concentration gradient for dyes and biomolecules. The microfluidic device was described mathematically, statistically and was suitable for reusable analytical and bioanalytical analysis. The device reproducibility was assessed by experimental tests, which have shown the same gradient concentration profile for different dyes and statistical reproducibility with 95% confidence interval for bovine serum albumin (BSA). Moreover, the experimental data converged well with those  obtained by computational fluid dynamics simulation. Applicability was verified by coupling the microfluidic device to a surface plasmon resonance (SPR) biosensor, based on nanohole arrays with sensitivity of 358.7 nm RIU -1 determined by white-light SPR excitation exposed to different D-(+)-glucose aqueous solutions with 1.3361-1.4035 refractive index interval. The transmission light intensities obtained by the array of images allowed to quantify a pseudo-unknown BSA sample (160 µg mL -1 ) at 138 µg mL -1 . The SPR analysis has been validated in parallel by fluorescence emissions, which showed a concentration of 154.8 ± 16.6 µg mL -1 ., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)