Since natural cellulose is mostly cellulose I and has a fibrous form, most cellulose-based adsorbents are fibrous/rod-shaped and exhibit the cellulose I crystal structure. This study reports a cellulose II-based spherical nanoparticle microcluster adsorbent (SNMA), synthesized from biomass by a bottom-up approach, for removing toxic hexavalent chromium (Cr(VI)). The basic structure of SNMA was investigated. Notably, the prepared adsorbent was a microcluster composed of spherical nanoparticles, while exhibiting cellulose II crystal structure, resulting in higher thermal stability and significantly enhanced adsorption performance. The adsorption process and mechanism of SNMA on Cr(VI) were studied in detail. The SNMA achieved a high adsorption capacity (225.94 mg/g) and receptor site density. The SNMA is expected to be used as a bio-based spherical nanoparticle microcluster adsorbent platform for the adsorption of different toxic substances by changing the surface functional groups of its components, spherical nanoparticles.
A facile and ultrasensitive sensor based on gold microclusters (AuMCs) electrodeposited on sulfonate functionalized graphene (SF-GR) was fabricated, and applied for the simultaneous determination of gallic acid (GA) and uric acid (UA). Taking advantage of the unique plane structure of the functionalized graphene (GR), the AuMCs were successfully electrodeposited on functionalized GR immobilized on the surface of a GCE. The results of scanning electron microscope (SEM) and energy spectrum analysis illustrated that AuMCs were deposited on the functionalized GR film. In comparison with the bare GCE, the pristine AuMCs and the pristine SF-GR modified electrode, AuMCs/SF-GR/GCE exhibited excellent electrochemical oxidation toward GA and UA. In addition, the two compounds were separated completely in 0.10 M citric acid-sodium citrate buffer (pH 4.0) by differential pulse voltammetry (DPV) under optimum conditions. The anodic current was linearly related with 0.05–8.0 μM GA and 0.2–50.0 μM UA, with the detection limit of 10.7 nM and 0.12 μM, respectively. Furthermore, AuMCs/SF-GR/GCE was successfully applied to the independent determination of GA in black tea and Cortex moutan as well as the simultaneous determination of GA and UA in urine samples.
Bitao Lu,Enling Hu,Ruiqi Xie,Kun Yu,Fei Lu,Rong Bao,Chenhui Wang,Guangqian Lan,Fangyin Dai
Complex yet lethal wounds with uncontrollable bleeding hinder conventional hemostats from clotting blood at the source or deep sites of injury vasculature, thereby causing massive blood loss and significantly increased mortality. Inspired by the attack action of torpedoes, we synthesized microcluster (MC) colloidosomes equipped with magnetic-mediated navigation and “blast” systems to deliver hemostats into the cavity of vase-type wounds. CaCO 3 /Fe 2 O 3 (CF) microparticles functionalized with Arg-Gly-Asp (RGD) modified polyelectrolyte multilayers were co-assembled with oppositely charged zwitterionic carbon dots (CDs) to form MC colloidosomes, which were loaded with thrombin and protonated tranexamic acid (TXA-NH 3 + ). The composite microparticles moved against blood flow under magnetic mediation and simultaneously disassembled for the burst release of thrombin stimulated by TXA-NH 3 + . The CO 2 bubbles generated during disassembly produced a “blast” that propelled thrombin into the wound cavity. Severe bleeding in a vase-type hemorrhage model in the rabbit liver was rapidly controlled within ∼60 s. Furthermore, in vivo subcutaneous muscle and liver implantation models demonstrated excellent biodegradability of MC colloidosomes. This study is the first to propose a novel strategy based on the principle of torpedoes for transporting hemostats into vase-type wounds to achieve rapid hemostasis, creating a new paradigm for combating trauma treatment.
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