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Cellulose from vegetable sources is the most abundant biopolymer on earth. In plants, cellulose is a reinforcement element that conforms to a hierarchical structure. Cellulose micro-/nanofibers can be isolated from the cell wall by top-down strategies involving mechanical processes to be used in applications as a reinforcing material. Nonetheless, its use has been limited as its extraction in an aqueous medium is unfavorable when employed in low-hydrophilic matrices. Therefore, this work proposes a novel homogenization route in which cellulose micro-/nanofibers are directly obtained and dispersed in propylene glycol (PG), which generates more possibilities for these (nano) structures in applications that require water-free environments. Moreover, the influence on the cycle numbers in the morphological, chemical, thermal, and rheological properties was researched. Thus, the obtained micro-/nanofibers presented TEM diameters even below 20 nm. XRD analysis evidenced crystalline planes located at 1 1 ¯ 0 , 110, and 200, and crystallinity degree values up to 80%. Also, FTIR spectra bands in 3340 cm−1, 2890 cm−1, 1314 cm−1, and in the fingerprint region corresponded to native cellulose Iβ. FTIR and TGA confirmed no influence of mechanical cycles on cellulose fibers' chemical and thermal properties. Furthermore, the increase in the cycle number evidenced a shear-thinning rheological behavior of the suspensions. Considering the above results, it was concluded that the proposed high-pressure homogenization within PG is an approach for vegetable nanocellulose homogenization while maintaining high crystallinity, thermal, and chemical features with huge importance for subsequent processes in the development of nanocomposites with hydrophilic matrices for industrial applications. [ABSTRACT FROM AUTHOR]

Echinochrome A (EchA), a marine bioactive pigment isolated from various sea urchin species, is the active agent of the clinically approved drug Histochrome®. EchA is currently only available in the form of an isotonic solution of its di- and tri-sodium salts due to its poor water solubility and sensitivity to oxidation. Electrospun polymeric nanofibers have lately emerged as promising drug carriers capable of improving the dissolution and bioavailability of drugs with limited water solubility. In the current study, EchA isolated from sea urchins of the genus Diadema collected at the island of Kastellorizo was incorporated in electrospun micro-/nanofibrous matrices composed of polycaprolactone and polyvinylpyrrolidone in various combinations. The physicochemical properties of the micro-/nanofibers were characterized using SEM, FT-IR, TGA and DSC analyses. The fabricated matrices exhibited variable dissolution/release profiles of EchA, as evidenced in in vitro experiments using gastrointestinal-like fluids (pH 1.2, 4.5 and 6.8). Ex vivo permeability studies using the EchA-loaded micro-/nanofibrous matrices showed an increased permeation of EchA across the duodenum barrier. The results of our study clearly show that electrospun polymeric micro-/nanofibers represent promising carriers for the development of new pharmaceutical formulations with controlled release, as well as increased stability and solubility of EchA, suitable for oral administration, while offering the potential for targeted delivery. [ABSTRACT FROM AUTHOR]

Developing multifunctional triboelectric nanogenerators (TENGs) with special intelligence is of great significance for next‐generation self‐powered electronic devices. However, the relevant work on the intelligent TENGs, especially those spontaneously responsive to external stimuli, is rarely reported. Herein, an intelligent TENG with thermal‐triggered switchable functionality and high triboelectric outputs is developed by designing a movable triboelectric layer, which is driven by a two‐way shape memory polyurethane. The resultant TENG device can be spontaneously switched on/off in response to the environmental temperature change, i.e., switching on at 0 °C and off at 60 °C. At the "on" state, the developed TENG exhibits excellent triboelectric performance with a maximum output power density of 5.15 W m−2 at a pressure of 30 kPa due to the unique advantages of micro‐/nanofiber triboelectric surfaces. Furthermore, the great potential of the switchable TENG in intelligent wearable electronic applications is demonstrated, which can serve as not only the sensing element for monitoring human movement and physical condition in a cold environment but also the thermal‐driven switch for turning on/off the heating function on demand. The intelligent "on–off" switchable TENG combined with excellent triboelectric performance may provide new opportunities for future self‐powered wearable electronics. [ABSTRACT FROM AUTHOR]

Echinochrome A (EchA), a marine bioactive pigment isolated from various sea urchin species, is the active agent of the clinically approved drug Histochrome®. EchA is currently only available in the form of an isotonic solution of its di- and tri-sodium salts due to its poor water solubility and sensitivity to oxidation. Electrospun polymeric nanofibers have lately emerged as promising drug carriers capable of improving the dissolution and bioavailability of drugs with limited water solubility. In the current study, EchA isolated from sea urchins of the genus Diadema collected at the island of Kastellorizo was incorporated in electrospun micro-/nanofibrous matrices composed of polycaprolactone and polyvinylpyrrolidone in various combinations. The physicochemical properties of the micro-/nanofibers were characterized using SEM, FT-IR, TGA and DSC analyses. The fabricated matrices exhibited variable dissolution/release profiles of EchA, as evidenced in in vitro experiments using gastrointestinal-like fluids (pH 1.2, 4.5 and 6.8). Ex vivo permeability studies using the EchA-loaded micro-/nanofibrous matrices showed an increased permeation of EchA across the duodenum barrier. The results of our study clearly show that electrospun polymeric micro-/nanofibers represent promising carriers for the development of new pharmaceutical formulations with controlled release, as well as increased stability and solubility of EchA, suitable for oral administration, while offering the potential for targeted delivery.

Abstract: Organic–inorganic halide perovskite (OHP) materials have attracted remarkable attention for the great promise of optoelectronic applications. Unfortunately, hysteresis in the current–voltage response links to the stability and reliability assessment of OHP photovoltaic device that must be addressed. Here, light‐induced antipolar resistive switching (RS) effect is demonstrated in an individual MAPbI3 micro‐/nanofiber–based two‐terminal device after aging for 4 d. The antipolar RS is attributed to reversible electrochemical reactions in the vicinity of Ag electrode, where Ag serves as the work electrode and MAPbI3 acts as the solid electrolyte. That makes conductive behavior of antipolar RS similar with cyclic voltammetry curves of capacitances. Concomitantly, the antipolar RS shows slow dissipation kinetics, which is employed to realize the application of nonvolatile memories. This work establishes the potential for the versatile solid state devices that can efficiently couple interface reaction, charge migration, and photoelectrical effects in an individual micro‐/nanodevice. [ABSTRACT FROM AUTHOR]

In this paper, we reported the preparation of micro-/nanofibers via co-assembly with paclitaxel (PTX) and dextran (DEX). The co-assembly fibers formed in PTX and DEX mixture solution via non-covalent interactions including hydrophilic/hydrophobic interactions and π-π stacking. The micro-/nanofibers could be obviously observed when the mixed solution became turbid and ivory-white in color. The properties of fibers were characterized by SEM, TEM, FTIR, DSC, XRD, in vitro release and MTT assay. The length of fibers could reach several centimeters. The diameter of microfibers and nanofibers was about 800 nm and 80 nm, respectively. In addition, the PTX loading efficiency was over 78% in co-assembly fibers and up to 84% when PTX and DEX (Mw: 40,000) both were 2 mg/mL. The sustained drug release and low cytotoxicity in vitro of PTX/DEX fibers were also demonstrated. Therefore, we believe that PTX/DEX micro-/nanofibers would have great potential for drug delivery of PTX. [ABSTRACT FROM AUTHOR]