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Functional platinum-based carbonous nanostructures play important roles in exploring new electrode materials by constructing sensitive and selective platform in the electrochemical detection. In recent years, intense research efforts have focused on boosting the performance of platinum with desirable activity and stability. This work reports a facile strategy for the synthesis of platinum-based nitrogen-doped porous C x N 1-x compounds (Pt-pC x N 1-x ) with excellent enzyme-like activity. In the strategy, Pt-pC x N 1-x was simply prepared by in situ synthesis through a one-step microwave-assisted heating procedure, resulting with subnanometer-size (∼2.5 nm) platinum-based nanoparticles (Pt-BNPs) loaded on the multi-dimensional C x N 1-x structure. Due to the enriched edge and corner atoms, Pt-pC x N 1-x showed excellent intrinsic peroxidase-like activity. Meanwhile, it was demonstrated that Pt-pC x N 1-x possessed a lower Michaelis Constant ( K m = 0.104) compared with horseradish peroxidase (HRP) ( K m = 0.416) in the presence of 3,3,5,5-tetramethylbenzidine (TMB) and hydrogen peroxide (H 2 O 2 ). Moreover, the Pt-pC x N 1-x behaved better property and lower cost in H 2 O 2 electrochemical detection compared with the pC x N 1-x and Pt-BNPs. The detection results exhibited a low detection limit (2.29 μM) and a wide linear range (0.025 to 5.725 mM), which revealed its superior potential in H 2 O 2 electrochemical detection. Therefore, the Pt-pC x N 1-x may find a potential application in constructing electrochemical biosensors.

Improving the performance of conventional enzyme-linked immunosorbent assay (ELISA) is of great importance to meet the demand of early clinical diagnosis of various diseases. Herein, we report a feasible enzyme-free immunosorbent assay (EFISA) system using antibody conjugated Au-Pt/SiO2 nanocomposites (APS NCs) as labels. In this system, Au-Pt/SiO2 nanospheres (APS NPs) were first synthesized by wet chemical method and exhibited intrinsic peroxidase and catalase-like activity with excellent water-solubility. Then APS NCs were utilized as labels to replace HRP conjugated antibody, and Fe3O4 magnetic beads (MBs) to entrap the analyte. To discuss the performance of EFISA system, Human IgG was served as a model analyte, and porcine circovirus type 2 (PCV2) serums as real samples. The system boosted the detection limit of HIgG to 75pgmL(-1) with a RSD below 5%, a 264-fold improvement as compared with conventional ELISA. This is the first time that APS NCs have been used and successfully optimized for the sensitive dilution detection of PCV2 antibody (5:10(7)) in ELISA. Besides, APS NCs have advantages related to low cost, easy preparation, good stability and tunable catalytic activity, which make them a potent enzyme mimetic candidate and may find potential applications in bioassays and clinical diagnostics.

Control of structure-enriched abundant unsaturated or dangling bonds can precisely and effectively tune the activity and durability of materials. In this study, a new strategy to obtain fusiform nanoarchitectures (FNAs) has been found for the first time using Te nanostructures as the model materials. TeFNA could be transformed from Te nanorods (NRs) with different diameter (50, 25 nm), even the ultrathin nanowires (NWs) (10 nm). Besides, a novel perspective into the preliminary mechanism combining collision theory with density functional theory simulations was proposed to explain the transformation progress. In the mixing system of hexadecyl trimethylammonium bromide (CTAB) solution, the Te NR/NWs keep the translational motion together with the centroid rotation. The velocity of the two ends of TeNR/NWs is higher than that in the center under the reaction condition based on collision theory; meanwhile, the summation energy of both O2 and CTAB put on Te (0001) surface is −606.992 eV, which means that the T...

A novel and green multifunctional nanoplatform as a nanocarrier for drug delivery, cell imaging, and phototherapy has been engineered. The nanoplatform is composed of stabilized carbon spheres (CSs) as cores, a coated polydopamine (PDA) shell, targeted folic acid (FA), and the loaded anticancer drug indocyanine green (ICG), obtaining CSs@PDA-FA@ICG nanocomposites (NCs). The biocompatible PDA shell provided a high fluorescence quenching efficiency and a surface rich in functional groups for anchoring FA for targeting cancer cells. Aromatic ICG could be effectively loaded into the CSs@PDA-FA system via hydrophobic interactions and π-π stacking with a loading efficiency of 58.9%. Notably, the activated NIR fluorescence in an intracellular environment made CSs@PDA-FA@ICG a sensitive "OFF" to "ON" nanoprobe that can be used for NIR imaging. Moreover, compared to ICG alone, the CSs@PDA-FA@ICG NCs could induce efficient photoconversion for simultaneous synergetic photodynamic therapy (PDT) and photothermal therapy (PTT) under a single NIR laser irradiation. The results demonstrated that CSs@PDA-FA@ICG NCs as a targeted and activated nanoplatform provide new opportunities to facilitate the accurate diagnosis of cancer and enhanced treatment efficacy. This work stimulates more interest in the design of the facile surface functionalization strategy to construct other multifunctional nanocomposites, such as nanotubes and nanorods.