Multi-function PtCo nanozymes/CdS nanocrystals@graphene oxide luminophores and KSO/HO coreactants-based dual amplified electrochemiluminescence immunosensor for ultrasensitive detection of anti-myeloperoxidase antibody. Yang Wei,Zhou Zheng,Wu Haiping,Liu Changjin,Shen Bo,Ding Shijia,Zhou Yonglie Journal of nanobiotechnology BACKGROUND:Anti-myeloperoxidase antibody (anti-MPO) is an important biomarker for anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitides (AAVs). However, the complicated operation procedures and insufficient sensitivity of conventional anti-MPO detection methods limit their application in monitoring efficacy of AAVs in clinical diagnosis. Herein, a dual amplified electrochemiluminescence (ECL) immunosensor based on multi-function PtCo nanozymes/CdS nanocrystals@graphene oxide (PtCo/CdS@GO) luminophores and KSO/HO coreactants has been fabricated for ultrasensitive detection of anti-MPO. RESULTS:PtCo/CdS@GO luminophores as novel signal amplification labels and nanocarriers to load rabbit anti-mouse IgG were synthesized by co-doping with Pt and Co nanozymes simultaneously with several considerable advantages, including astonishing peroxidase-like catalytic activity, high-efficiency luminescence performance and superior stability in aqueous solutions. Meanwhile, upon the KSO/HO coreactants system, benefiting from the efficient peroxidase-like activity of the PtCo/CdS@GO toward HO, massive of transient reactive intermediates could react with KSO, thus obtaining higher ECL emission. Therefore, the developed ECL immunosensor for anti-MPO detection displayed good analytical performance with good concentration linearity in the range of 0.02 to 1000 pg/mL and low detection limit down to 7.39 fg/mL. CONCLUSIONS:The introduction of multi-function PtCo/CdS@GO luminophores into the established ECL immunoassay not only was successfully applied for specific detection of anti-MPO in clinical serum samples, but also provided a completely new concept to design other high-performance luminophores. Meaningfully, the ECL immunoassay strategy held wide potential for biomarkers detection in clinical diagnosis. 10.1186/s12951-021-00968-4

A dual-quenched ECL immunosensor for ultrasensitive detection of retinol binding protein 4 based on luminol@AuPt/ZIF-67 and MnO@CNTs. Gong Wei,Yang Suqing,Zhang Fen,Tian Fengshun,Chen Junman,Yin Zhigang,Ding Shijia,Yang Wei,Luo Rong Journal of nanobiotechnology BACKGROUND:Retinol binding protein 4 (RBP4) has been regarded as an important serological biomarker for type 2 diabetes mellitus (T2DM). Hence, the construction of a highly sensitive detection method for RBP4 is the key to early prevention and multidisciplinary intervention of T2DM. In this work, a dual-quenched electrochemiluminescence (ECL) immunosensor has been fabricated for ultrasensitive detection of RBP4 by combining zeolitic imidazolate framework-67/AuPt-supported luminol (luminol@AuPt/ZIF-67) with MnO nanosheets-grown on carbon nanotubes (MnO@CNTs). RESULTS:AuPt/ZIF-67 hybrids with high-efficiency peroxidase-like activity could provide multipoint binding sites for luminol and antibodies and significantly boost the amplified initial signal of the ECL immunosensor. Upon glutathione/HO coreactants system, MnO@CNTs composites could quench the initial signal by inhibiting mimic peroxidase activity of luminol@AuPt/ZIF-67. Moreover, the absorption spectrum of the MnO@CNTs composites completely overlaps with the emission spectrum of luminol, which can further reduce initial signal by ECL resonance energy transfer (ECL-RET). CONCLUSIONS:Benefiting from the above-mentioned properties, the designed immunoassay sensitivity exhibited excellent sensitivity and relative stability for RBP4 detection range from 0.0001 to 100 ng mL with a low detection limit of 43 fg mL. Therefore, our ECL immunosensor provides an alternative assaying strategy for early diagnosis of T2DM. 10.1186/s12951-021-01020-1

Reversible capturing and voltammetric determination of circulating tumor cells using two-dimensional nanozyme based on PdMo decorated with gold nanoparticles and aptamer. Yang Wei,Fan Lu,Guo Zhen,Wu Haiping,Chen Junman,Liu Changjin,Yan Yurong,Ding Shijia Mikrochimica acta A novel cytosensor was constructed for the ultrasensitive detection and nondestructive release of circulating tumor cells (CTCs) by combining Au nanoparticles-loaded two-dimensional bimetallic PdMo (2D Au@PdMo) nanozymes and electrochemical reductive desorption. The 2D Au@PdMo nanozymes possessed high-efficiency peroxidase-like activity and were assembled with an aptamer composed of a thiol-modified epithelial specific cell adhesion molecule (EpCAM) to strengthen CTCs adhesion. Moreover, the electrode surface was decorated with highly fractal Au nanostructures (HFAuNSs) composites due to the similarity in fractal nanostructure with the CTCs membrane to enhance the CTCs anchoring efficiency and release capability. The captured CTCs could be further efficiently dissociated and nondestructively released from the modified electrodes upon electrochemical reductive desorption. The designed cytosensor showed an excellent analytical performance, with a wide linear range from 2 to 1 × 10 cells mL and low limit of detection (LOD) of 2 cells mL (S/N = 3) at the working potential in the range  -0.6 to 0.2 V. A satisfactory CTCs release reaching a range of 93.7-97.4% with acceptable RSD from 3.55 to 6.41% and good cell viability was obtained. Thus, the developed cytosensor might provide a potential alternative to perform CTC-based liquid biopsies, with promising applications in early diagnosis of tumors. Preparation and mechanism of desorption of the cytosensor based on 2D Au@PdMo nanozymes and electrochemical reductive desorption for the detection and release of CTCs. A Preparation procedure of the Apt/Au@PbMo bioconjugates. B Fabrication process of the sandwich-type cytosensor. C Electrochemical signal produced by the Au@PdMo nanozymes. D Mechanism of electrochemical reductive desorption for CTCs release. 10.1007/s00604-021-04927-6

Multiple RNA Rapid In Situ Imaging Based on Cas9 Code Key System. Small methods Existing RNA in situ imaging strategies mostly utilize parallel repetitive nucleic acid self-assembly to achieve multiple analysis, with limitations of complicated systems and cumbersome steps. Here, a Cas9 code key system with key probe (KP) encoder and CRISPR/Cas9 signal exporter is developed. This system triggers T-protospacer adjacent motif (T-PAM structural transitions of multiple KP encoders to form coding products with uniform single-guide RNA (sgRNA) target sequences as tandem nodes. Only single sgRNA/Cas9 complex is required to cleave multiple coding products, enabling efficient "many-to-one" tandem signaling, and non-collateral cleavage activity-dependent automatic signaling output through active introduction of mismatched bases. Compared with conventional parallel multiple signaling analysis model, the proposed system greatly simplifies reaction process and enhances detection efficiency. Further, a rapid multiple RNA in situ imaging system is developed by combining the Cas9 code key system with a T-strand displacement amplification (T-SDA) signal amplifier. The constructed system is applied to tumor cells and clinicopathology slices, generating clear multi-mRNA imaging profiles in less than an hour with just one step. Therefore, this work provides reliable technical support for clinical tumor typing and molecular mechanism investigation. 10.1002/smtd.202400195

PtCo nanocubes/reduced graphene oxide hybrids and hybridization chain reaction-based dual amplified electrochemiluminescence immunosensing of antimyeloperoxidase. Yang Wei,Peng Qiling,Guo Zhen,Wu Haiping,Ding Shijia,Chen Yongjian,Zhao Min Biosensors & bioelectronics Antimyeloperoxidase (anti-MPO) is regarded as one of the most important circulating autoantibodies for anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitides (AAVs). Hence, it is crucial for highly sensitive detection of anti-MPO to monitor efficacy of AAVs in clinical diagnosis. Herein, a highly sensitive electrochemiluminescence (ECL) immunosensor for anti-MPO detection was constructed by combining reduced graphene oxide-supported PtCo nanocubes hybrids (PtCo@rGO) with hybridization chain reaction (HCR) as signal amplification. Multiple ECL luminophores (Dox-ABEI) prepared by cross-linking of N-(aminobutyl)-N-(ethylisoluminol) (ABEI) and doxorubicin (Dox) were intercalated into dsDNA products of HCR, achieving the effective immobilization of ECL luminophores to obtain strong ECL emission. Benefiting from the efficient catalytic activity of PtCo@rGO toward HO, the massive the superoxide radical (O-) were generated to further react with ABEI for ECL emission. Thus, the designed ECL immunoassay for anti-MPO detection exhibited excellent sensitivity of a concentration variation from 50 fg/mL to 1 ng/mL and a detection limit of 15.68 fg/mL. Importantly, this work proposed an enzyme-free ECL immunoassay with high sensitivity, excellent specificity for protein detection in clinical diagnosis. 10.1016/j.bios.2019.111548