Nanostructured materials have great potential as platforms for analytical assays and catalytic reactions. Herein, we report the synthesis of electrocatalytically active cobalt phosphate nanostructures (CPNs) using a simple, low-cost, and scalable preparation method. The electrocatalytic properties of the CPNs toward the electrooxidation of glucose (Glu) were studied by cyclic voltammetry and chronoamperometry in relevant biological electrolytes, such as phosphate-buffered saline (PBS), at physiological pH (7.4). Using the CPNs, Glu detection could be achieved over a wide range of biologically relevant concentrations, from 1 to 30 mM Glu in PBS, with a sensitivity of 7.90 nA/mM cm 2 and a limit of detection of 0.3 mM, thus fulfilling the necessary requirements for human blood Glu detection. In addition, the CPNs showed a high structural and functional stability over time at physiological pH. The CPN-coated electrodes could also be used for Glu detection in the presence of interfering agents (e.g., ascorbic acid and dopamine) and in human serum. Density functional theory calculations were performed to evaluate the interaction of Glu with different faceted cobalt phosphate surfaces; the results revealed that specific surface presentations of undercoordinated cobalt led to the strongest interaction with Glu, suggesting that enhanced detection of Glu by the CPNs can be achieved by lowering the surface coordination of cobalt.Our results highlight the potential use of phosphate-based nanostructures as catalysts for electrochemical sensing of biochemical analytes.Potassium chloride (KCl, CAS no. 7440-09-7) was purchased from Chem-Supply. All the chemicals were used as received. High purity (Milli-Q) water with a resistivity of 18.2 MΩ cm was obtained from an inline Millipore RiOs/Origin water purification system.Instrumentation. X-ray photoelectron spectroscopy (XPS) spectra were acquired using an Axis Ultra X-ray photoelectron spectrometer (Kratos Analytical, UK), equipped with a 165 mm concentric hemispherical electron energy analyzer and a monochromated Al Kα incident Xray source (1486.6 eV). Survey (wide) scans were recorded in the binding energy range of 0-1200 eV, with 1.0 eV steps, a dwell time of 100 ms, and an analyzer pass energy of 160 eV.Multiplex (narrow) high-resolution spectra were recorded with a pass energy of 20 eV, with 0.05 eV steps, and a dwell time of 250 ms, resulting in an energy resolution (ΔE/E) of ~300 meV. The base pressure in the analysis chamber during data collection was 1-2 × 10 −9 mbar, and these data were processed using the software CasaXPS. All binding energies were calibrated using the C 1s level of adventitious carbon at 285.0 eV. Fourier transform infrared (FTIR) spectra were obtained on a Tensor II (Bruker) attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectrometer and analyzed using the software OPUS 7.8. The number of scans was 64. A minimum resolution of 4 cm −1 and the absorbance/transmittance mode were used. Scanning electron microscopy (SEM) images were o...

Metal contamination of water bodies from industrial effluents presents a global threat to the aquatic ecosystem. To address this challenge, metal sequestration via adsorption onto solid media has been explored extensively. However, existing sorbent systems typically involve energy-intensive syntheses and are applicable to a limited range of metals. Herein, a sorbent system derived from physically cross-linked polyphenolic networks using tannic acid and Zr IV ions has been explored for high affinity, broad-spectrum metal sequestration. The network formation step (gelation) of the sorbent is complete within 3 min and requires no special apparatus. The key to this system design is the formation of a highly stable coordination network with an optimized metal-ligand ratio (1.2:1), affording access to a major portion of the chelating sites in tannic acid for capturing diverse metal ions. The sorbent system effectively sequesters 28 metals in single-and multi-element model wastes, with removal efficiencies exceeding 99% and is stable over a pH range of 1-9. Furthermore, it is demonstrated that this system can be processed as membrane coatings, thin films, or wet gels to capture metal ions, and that both the sorbent and captured metal ions can be regenerated or directly used as composite catalysts.

Bio-sourced nanoparticles have a range of desirable properties for therapeutic applications, including biodegradability and low immunogenicity. Glycogen, a natural polysaccharide nanoparticle, has garnered much interest as a component of advanced therapeutic materials. However, functionalizing glycogen for use as a therapeutic material typically involves synthetic approaches that can negatively affect the intrinsic physiological properties of glycogen. Herein, the protein component of glycogen is examined as an anchor point for the photopolymerization of functional poly(N-isopropylacrylamide) (PNIPAM) polymers. Oyster glycogen (OG) nanoparticles partially degrade to smaller spherical particles in the presence of protease enzymes, reflecting a population of surface-bound proteins on the polysaccharide. The grafting of PNIPAM to the native protein component of OG produces OG-PNIPAM nanoparticles of ~45 nm in diameter and 6.2 MDa in molecular weight. PNIPAM endows the nanoparticles with temperatureresponsive aggregation properties that are controllable, reversible, and which can be removed by the biodegradation of the protein. The OG-PNIPAM nanoparticles retain the native biodegradability of glycogen. Whole blood incubation assays revealed that the OG-PNIPAM nanoparticles have a low cell association and inflammatory response similar to that of OG. The reported strategy provides functionalized glycogen nanomaterials that retain their inherent biodegradability and low immune cell association.

Amphiphilic phytoglycogen nanoparticles are used as building blocks for engineering multifunctional hybrid films with catalytic and sensing properties.

Engineering reactive and functional nanostructured surfaces is important for enhancing the sensitivity and versatility of biosensors and microreactors. For example, the assembly of hybrid inorganic–organic porous microparticles on surfaces may provide a catalytic microenvironment for a wide range of reactions. Herein, the synthesis of catalytically active porous dextran sulfate–copper phosphate hybrid microparticles by a facile and rapid crystallization process in aqueous solution is reported. The sulfated polysaccharide enables control over the size and hierarchical morphology of the hybrid microparticles, as well as their assembly into stable macroporous coatings. The engineered microparticle coatings display intrinsic nonenzymatic peroxidase‐like catalytic activity when employed as a platform for the detection of hydrogen peroxide. Pairing of the microparticle coating with glucose oxidase affords a hybrid platform that is employed as a glucose sensor for monitoring physiological concentrations of a given analyte via a hybrid enzymatic/nonenzymatic cascade reaction. This work presents a strategy for the assembly of hybrid porous microparticles into enzyme‐mimicking surfaces for copper‐based catalysis and biochemical analyte sensing.