Buffer‐Stable Chitosan–Polyglutamic Acid Hybrid Nanoparticles for Biomedical Applications

In spite of their attractive features, widespread biomedical applications of CS nanoparticles are yet to be realized due to their poor stability in physiological conditions, such as in buffer system at pH 7.4. Buffer‐stable chitosan‐based hybrid NPs (HNPs) are reported and characterized. Buffer stability is achieved by introducing polyglutamic acid to chitosan. The effect of PGA to CS molar ratio and crosslinking on HNP integrity, buffer stability, and biodegradability are studied. Preliminary in vitro studies are carried out to evaluate targeted uptake efficiency of folate conjugated HNPs. Successful demonstration of buffer stability and cancer cell targeting by HNPs achieves important milestones for chitosan‐based nanoparticle technology.

     

Screen‐Printed Electrochemical 96‐Well Plate: a High‐Throughput Platform for Multiple Analytical Applications

A new screen‐printed electrochemical array formed by 96 three‐electrode electrochemical cells with carbon‐based working electrodes (DRP‐96X110) was developed by DropSens. The electrochemical and electro(analytical) performance of this multiple‐analysis plate is herein presented. Different proofs of concept relying on reference benchmark redox compounds, streptavidin‐biotin high affinity interactions and magnetic‐based immunoassays were carried out. The results showed the electrochemical plate versatility and usefulness as an innovative high‐throughput transducer surface for multiple and decentralized applications.     

Mesoporous Bubble‐like Manganese Silicate as a Versatile Platform for Design and Synthesis of Nanostructured Catalysts

Manganese silicate in bubble‐like morphology was used as a versatile platform to prepare a new class of yolk–shell hybrids. The mesoporosity of the shell was generated from the interbubble space and the bubble structure of manganese silica was used to hold and support nanoparticles (e.g., Au, Ag, Pt, Co, Ni, Au–Pd alloy, MoO₂, Fe₃O₄, carbon nanotubes and their combinations). We also used heterogeneous catalysis reactions to demonstrate the workability of these catalysts in both liquid and gas phases.     

Azidopropylvinylsulfonamide as a New Bifunctional Click Reagent for Bioorthogonal Conjugations: Application for DNA–Protein Cross‐Linking

N‐(3‐Azidopropyl)vinylsulfonamide was developed as a new bifunctional bioconjugation reagent suitable for the cross‐linking of biomolecules through copper(I)‐catalyzed azide–alkyne cycloaddition and thiol Michael addition reactions under biorthogonal conditions. The reagent is easily clicked to an acetylene‐containing DNA or protein and then reacts with cysteine‐containing peptides or proteins to form covalent cross‐links. Several examples of bioconjugations of ethynyl‐ or octadiynyl‐modified DNA with peptides, p53 protein, or alkyne‐modified human carbonic anhydrase with peptides are given.     

“Clickable” and Antifouling Block Copolymer Brushes as a Versatile Platform for Peptide‐Specific Cell Attachment

To tailor cell–surface interactions, precise and controlled attachment of cell‐adhesive motifs is required, while any background non‐specific cell and protein adhesion has to be blocked effectively. Herein, a versatile and highly reproducible antifouling surface modification based on “clickable” groups and hierarchically structured diblock copolymer brushes for the controlled attachment of cells is reported. The polymer brush architecture combines an antifouling bottom block of poly(2‐hydroxyethyl methacrylate) poly(HEMA) and an ultrathin azide‐bearing top block, which can participate in well‐established “click” reactions including the highly selective copper‐catalyzed alkyne‐azide cycloaddition (CuAAC) reaction under mild conditions. This straightforward approach allows the rapid conjugation of a cell‐adhesive, alkyne‐bearing cyclic RGD peptide motif, enabling subsequent specific attachment of NIH 3T3 fibroblasts, their extensive proliferation and confluent cell sheet formation after 48 h of incubation. The generally applicable strategy presented in this report can be employed for surface functionalization with diverse alkyne‐bearing biological moieties via CuAAC or copper‐free alkyne‐azide cycloaddition protocols, making it a versatile functionalization approach and a promising tool for tissue engineering, biomaterial implant design, and other applications that require surfaces supporting highly specific cell attachment.     

Reactive Hybrid of Polyhedral Oligomeric Silsesquioxane (POSS) and Sulfur as a Building Block for Self‐Healing Materials

This work demonstrates a new reactive and functional hybrid (S‐MMA‐POSS) of polyhedral oligomeric silsesquioxane (POSS) and sulfur prepared with a direct reaction between a multifunctional methacrylated POSS compound (MMA‐POSS) and elemental sulfur (S₈) through the “inverse vulcanization” process. S‐MMA‐POSS is an effective building block for imparting self‐healing ability to the corresponding thermally crosslinked POSS‐containing nanocomposites through a self‐curing reaction and co‐curing reaction with conventional thermosetting resins. Moreover, S‐MMA‐POSS is also a useful precursor for preparation of materials with high transparency in mid‐infrared region.