Microchimica Acta最新文献

An aptamer-gated metal-organic framework-based biosensing platform for highly sensitive detection of multidrug-resistant bacteria (MDRB) has been developed. This biosensing platform utilizes aptamers as specific "gated" switches, which are integrated with the UiO-66-NH₂ MOFs to construct a "gated" sensing system loaded with 3,3',5,5'-tetramethylbenzidine (TMB). The entry of target bacteria induces specific dissociation of sDNA/Apt, forming an aptamer-bacteria complex on the UiO-66-NH₂ surface while releasing TMB into the solution. Subsequently, the PCN-224-Mn nanozyme catalyzes the oxidation of TMB, generating a colorimetric signal. This biosensing platform demonstrates a broad linear range for detecting New Delhi metallo-β-lactamase-1 Klebsiella pneumoniae (NDM-1 KP) and multidrug-resistant Acinetobacter baumannii (MDR-AB), achieving ultra-high sensitivity with detection limits of 5 CFU/mL and 7 CFU/mL, respectively. The practical performance of this biosensing platform was evaluated through spiked recovery experiments. Its excellent recovery demonstrates that the method maintains high reliability and stability even when applied to complex real-world samples, providing an effective technical solution for addressing challenges in microbial detection in practical scenarios.

Acinetobacter baumannii (A. baumannii) is a Gram-negative bacterium that creates an increasing burden on the healthcare system due to its ability to develop multidrug resistance. Sensitive, rapid and on-site detection of A. baumannii, which has been declared a critical priority pathogen by the World Health Organization, is of great importance. Today, secretory proteins of pathogenic organisms attract attention not only for their role in invasive processes but also as targets for early diagnosis. In this context, SPSFQ, a recently identified secretory protease, is a valuable target for the detection of A. baumannii at very low initial levels, before significant colonization occurs. In this study, ssDNA aptamers for SPSFQ were selected for the first time using the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) method. The two aptamer sequences identified through SELEX were named Apt1 and Apt2, with Kd values of 42.10 ± 6.7 nM and 26.98 ± 1.35 nM, respectively. An ultrasensitive EIS-based biosensor was developed using Apt2, achieving a detection limit of 5.44 fg/mL and a linear range of 1.0-10,000 fg/mL. The aptasensor exhibited good repeatability (RSD: 2.62%) and reproducibility (RSD: 6.62%), and also maintained satisfactory stability during storage. Furthermore, the developed biosensor demonstrated reliable and remarkable performance in real commercial human serum samples, with recovery values of 110.84% and 104.40% for serum samples spiked with 250 and 6500 fg/mL SPSFQ, respectively.

ZnO has been used as template to prepare and regulate the structures of functional nanomaterials. Due to the structural characteristics of Zn, its nanomaterials are generally considered inert. This study presents an innovative ZnO-templated synthesis of hollow N-doped carbon materials with atomically dispersed Zn single atoms (Zn SA/NC), where ZnO uniquely serves dual roles as both structural template and Zn precursor. The synthesized Zn SA/NC exhibits remarkable bifunctionality, demonstrating exceptional electrocatalytic activity for H₂O₂ reduction (detection limit: 3.7 µM, sensitivity: 1285.7 µA·mM⁻¹·cm⁻²) and intrinsic peroxidase-like activity for TMB oxidation. Leveraging these properties, we developed a dual-mode H₂O₂ detection platform integrating electrochemical and colorimetric readouts. The work challenges conventional views on Zn's catalytic inertness by revealing that Zn-Nₓ sites enable efficient charge redistribution, while the hollow architecture enhances mass transport. This strategy bridges the gap between structural control and atomic dispersion in single-atom catalyst design.