Self-supporting noncovalent Choline Alginate/Tannic acid/Ag antibacterial films for strawberry preservation.

Packaging materials with peculiar antibacterial properties can shield off and inhibit microorganism proliferation, thus achieving packaging goals such as fresh-keeping, good hygiene, and biosafety. Especially, antibacterial films made of biocompatible substances have received wide attentions, which could effectively extend the shelf life, enhance food security, and guarantee economic benefits. Herein, a self-supporting hybrid antibacterial film was prepared based on non-covalently linked choline hydroxide (ChOH) and alginic acid (HAlg). Then tannic acid (TA) and silver ions were added to improve the mechanical and antimicrobial properties of this hybrid film. The rich hydroxyl groups from TA not only form multiple hydrogen bonds with ChAlg, but can also in situ reduce silver ions to silver nanoparticles, which were confirmed with various characterizations. In addition, the quantitative antibacterial test proved that the antibacterial rate was significantly improved after adding silver ions, reaching >60 %. In an actual storage test, we found that choline cation (Ch+) captured in antibacterial film by electrostatic interaction could achieve sustained release, i.e. sustainable bacteriostasis, and keep strawberries fresh for 48 h at room temperature. This work offers a new strategy for preparing antibacterial films via non-covalent weak interactions, explored an alternative antibacterial film for food packaging applications.

DNA Nanobarrel-Based Drug Delivery for Paclitaxel and Doxorubicin.

Co-delivery of anticancer drugs and target agents by endogenous materials is an inevitable approach towards targeted and synergistic therapy. Employing DNA base pair complementarities, DNA nanotechnology exploits a unique nanostructuring method and has demonstrated its capacity for nanoscale positioning and templated assembly. Moreover, the water solubility, biocompatibility, and modifiability render DNA structure suitable candidate for drug delivery applications. We here report single-stranded DNA tail conjugated antitumor drug paclitaxel (PTX), and the co-delivery of PTX, doxorubicin and targeting agent mucin 1 (MUC-1) aptamer on a DNA nanobarrel carrier. We investigated the effect of tail lengths on drug release efficiencies and dual drug codelivery-enabled cytotoxicity. Owing to the rapidly developing field of structural DNA nanotechnology, functional DNA-based drug delivery is promising to achieve clinical therapeutic applications.

Photovoltaic Energy Conversion and Storage of Micro-Supercapacitors Based on Emulsion Self-Assembly of Upconverting Nanoparticles.

With the rapid need for new kinds of portable and wearable electronics, we must look to develop flexible, small-volume, and high-performance supercapacitors that can be easily produced and stored in a sustainable way. An integrated system simultaneously converting recyclable energy to electricity and storing energy is sought after. Here we report photovoltaic energy conversion and storage integrated micro-supercapacitors (MSCs) with asymmetric, flexible, and all-solid-state performances constructed from thousands of close-packed upconverting nanoparticles (UCNPs) via an emulsion-based self-assembly process using oleic acid (OA)-capped upconverting nanoparticles. The carbonated-UCNPs supraparticles (CSPs) are further coated with polypyrrole (PPy) to improve their electrochemical performance. Such a design can develop CSPs@PPy as electrode materials with high gravimetric capacitance, 308.6 F g-1 at 0.6 A g-1. The fabricated MSCs exhibit excellent areal capacitance, C s = 21.8 mF cm-2 at 0.36 A cm-2 and E = 0.00684 mWh cm-2, and have superior flexibility and cycling ability. The MSC devices have a sensitive near-infrared ray (NIR) photoelectrical response capability, which can capture the NIR of sunlight to convert it into electrical energy and store the electric energy due to an excellent capacitive performance. We propose a method for multifunctional integration of energy conversion and storage, and provide future research directions and potential applications of self-powered flexible wearable photonic electronics.