Congyu Wang,Peng Wang,Jiawei Li,Yihan Sun,Wei Lu,Dun Zhang,Yi Wan,Shiyun Ai
Single-droplet electricity generator (SDEG) has superior potential over other solid–liquid triboelectric nanogenerators (TENGs) for energy harvesting. However, its shunting effect of parasitic capacitance is adverse and unavoidable, resulting in the reduction of the SDEG voltage. In addition, TENG-based bacterial biosensors are still facing issues of incompetence in resolution, precision, and specificity. Therefore, a novel SDEG-based bacterial biosensor is developed by making use of parasitic capacitance. By taking the advantages of aptamer and parasitic capacitance, the Pseudomonas aeruginosa ( P. aeruginosa ) can be specifically and precisely detected via signal change from a single droplet without energy accumulation. This study proves that the SDEG-based bacterial biosensor exhibits an excellent performance for P . aeruginosa detection in low limit of detection (4.5×10 3 CFU mL −1 ) with high selectivity. Meanwhile, the established mathematical model yields consistent results to the experimental ones, which serves as a solid basis for quantifying bacterial concentration. This work contributes to TENG-based bacterial biosensor, and opens up a new way for the diversified application of SDEG.
In this work, we propose a Ti 3 C 2 T x -based electrochemiluminescence (ECL) sensing platform, combined with a programmable entropy-driven cycling strategy and inverted DNA tetrahedral nanomachines to detect the SARS-CoV-2 RdRp gene. The use of Ti 3 C 2 T x in the ECL sensing platform provides unique advantages that improve the assay's sensitivity. Firstly, the SARS-CoV-2 RdRp gene triggers an entropy-driven cyclic amplification reaction to obtain a large number of Output strands. Subsequently, the Output strand reacts with an inverted DNA tetrahedral swing arm strand to start the self-driven process. Finally, the ferrocene (Fc)-labeled hairpin DNA strand of the inverted DNA tetrahedron is severed to achieve the signal change. Under optimal conditions, the ECL platform integrated with entropy-driven cycle amplification reaction and inverted DNA tetrahedral nanomachines obtained a wide range of 100 aM to 10 nM and a limit of detection (LOD) of 48.3 aM for the SARS-CoV-2 RdRp gene. Moreover, the recovery rates of 97% to 103.3% and 98.34% to 103% were obtained in real environments and human pharyngeal swabs, respectively. This ECL sensing platform, which combines an entropy-driven cycle amplification reaction and inverted DNA tetrahedral nanomachines, opens up new opportunities for the detection of other substances.
Rapid and accurate detection of pathogenic bacteria of Staphylococcus aureus ( S. aureus ) is of importance in the field of clinical research and practical application. Herein, we report a magnetic relaxation switching (MRS)-based strategy for detecting S. aureus in complex samples via the assistance of signal amplification system of liposome. In this design, vancomycin (Van) modified 200 nm magnetic beads (MB 200 -Van) and biotinylated immunoglobulin (Biotin-IgG) were employed as capture probes for S. aureus which following labelled by biotinylated liposomes loading with glucose molecule (Biotin-liposome@Glu, BLGs) based on the affinity of biotin with streptavidin. The released glucose molecules combining with glucose oxidase generated Fe 3+ , causing transverse relaxation time ( T 2 ) signal change. The combination of dual recognition of S. aureus , liposome assisted signal amplification, and the MRS-based assay achieved direct and specific detection of S. aureus in blood and abscess samples. The as-proposed method for S. aureus assay in this study shows potential application for infectious diagnosis in clinical.
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