Microchimica Acta最新文献

A high-throughput aptamer-based photothermal (PT) sensing platform has been developed using MnO₂@CuS nanoprobes for the noninvasive detection of exfoliated bladder cancer cells (HT-1376) in simulated liquid biopsy samples. A specific aptamer (Apt1) targeting epithelial cell adhesion molecule (EpCAM) was immobilized on an amino-functionalized glass slide to selectively capture target cells, and a thiolated aptamer-conjugated MnO₂@CuS nanoprobe (Apt2) was employed for photothermal signal output. Upon 808 nm laser irradiation, infrared thermographic imaging was used to monitor temperature elevation, enabling quantitative determination of cell concentration. The platform demonstrated a strong linear relationship between photothermal signal and HT-1376 concentration in the range 1.0 × 10 to 1.0 × 10⁶ cells/mL (R² = 0.993), with excellent sensitivity, selectivity, and repeatability. This is the first report of applying photothermal infrared imaging in a high-throughput format for tumor cell detection, offering a promising strategy for early and noninvasive diagnosis of bladder cancer via liquid biopsy.

Graphene-based biosensors are recognized as one of the most innovative tools in the fields of biological and medical diagnostics. This paper investigates the laser-induced graphene process and its impact on the electrical and chemical properties of biosensors. By employing advanced laser methods, researchers can finely tune both the architecture and functional characteristics of graphene, thereby improving the sensor’s ability to detect specific substances with greater accuracy and selectivity. We analyze the effects of various laser parameters, including wavelength and power, on the formation of graphene and the performance of biosensors. Experimental results demonstrate that laser-induced biosensors are capable of detecting biological analytes with high accuracy and rapid response times. These advancements contribute to the development of novel technologies for early disease detection and personal health monitoring. Finally, the challenges and future opportunities for further research on laser-induced graphene biosensors will be discussed.

Graphical Abstract

There is an urgent need for strategies that enable the rapid synthesis of long-wavelength fluorescent carbon dots (CDs). In forensic science, the development and analysis of latent fingerprints (LFPs) are vital for criminal investigations. This process involves two steps: enhancing LFP visualization for better detectability and using digital processing techniques for accurate database comparisons. Long-wavelength-emitting CDs can significantly improve LFP visualization by enhancing contrast and minimizing background interference. This study focuses on synthesizing dual green/red-emissive nitrogen and iron co-doped carbon dots (N, Fe-CD _green/red) using microwave-assisted methods. These N, Fe-CD _green/red were integrated into a plaster and starch composite, resulting in N, Fe-CD _green/red @plaster-starch phosphors. The phosphors effectively enhanced LFP development through dusting techniques. Under blue/green light excitation, the emitted green/red fluorescence from the N, Fe-CD _green/red significantly improved LFP visualization, proving their usefulness in forensic applications. Additionally, artificial intelligence (AI) algorithms were utilized to analyze fluorescence images of developed LFPs, achieving match scores exceeding 73.0%, which indicates a high similarity to control references. These findings highlight the AI algorithms’ effectiveness in reliably identifying and comparing fingerprint features.

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The development of cost-effective nanozymes with signal amplification function to overcome the limited sensitivity of lateral flow immunoassays (LFIAs) is of great significance. Here, we introduce the first Mn₂O₃-based colorimetric LFIA platform for sensitive C-reactive protein (CRP) detection. By confining Mn₂O₃ within dendritic mesoporous silica nanoparticles (DMSNs), DMSN-Mn₂O₃ nanozymes have been synthesized with enhanced active site exposure and uniform particle sizes. It is demonstrated that DMSN-Mn₂O₃ exhibits better catalytic performance compared to DMSN-MnO₂ and pure Mn₂O₃, showing the importance of control over both composition and nanostructure in enhancing the nanozyme functions. In the built H₂O₂-free colorimetric LFIA platform, DMSN-Mn₂O₃ demonstrates rapid catalytic amplification (30 s) for CRP detection, achieving a limit of detection of 0.25 ng mL⁻¹, a 6-fold improvement over conventional colloidal gold-based LFIAs. This work contributes to the rational design of high-performance nanozymes and provides a platform technology for point-of-care diagnostics with enhanced sensitivity.

Graphical Abstract

Rapid, low-cost, practical, disposable electrochemical panel immunosensor systems were developed for the individual and simultaneous determination of anterior gradient-2 protein (AGR2), folate receptor alpha (FOLR1), glycodelin (GLY), and soluble mesothelin-associated protein (SMRP), which are significantly increased in physiological fluids, particularly in ovarian cancer, and are potential biomarkers in the diagnosis of specific cancer types. To reduce the cost of the panel immunosensor system, the electrodes were hand-fabricated (HSPE), and then the HSPE surfaces were modified with gold nanoparticles (AuNPs). Surface analyses (SEM, XPS, FTIR) have confirmed that the sensor was manufactured robustly. The electrochemical characterization and analysis of the immunosensors were performed using electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry methods. Optimal operating conditions (antibody concentration, antigen, and antibody incubation times) were determined for the prepared single immunosensors. Detection limits, linear detection ranges, selectivity, shelf lives, repeatability, and reproducibility of single and panel immunosensors were determined. The clinical validity of the multi-platform was confirmed by recoveries of over 95% in human serum samples and by ELISA. In this study, low-cost electrochemical panel systems that enable the simultaneous determination of AGR2, GLY, FOLR1, and SMRP biomarkers with high selectivity and accuracy, a wide linear range (1-500 pg mL⁻¹), low detection limits, and good reproducibility were produced for the first time.

A pH-responsive carbon dot (CD) was synthesized using o-phenylenediamine and tyrosine as precursors via a one-step solvothermal method. The synthesized CDs were characterized using multiple analytical techniques, revealing UV-visible absorbance and excitation-independent fluorescence emission, diverse hydrophilic functional groups, crystalline structure with notable defects, and excellent optical stability, which is a key feature for their use as robust and reliable sensing material. The resulting CDs demonstrated visible absorbance and fluorescent intensity changes across the full pH range from 1 to 14, with a notable color change in solution, which has rarely been reported in the field of pH sensing by CDs. This pH responsiveness was further validated through tests on real solution samples, including fruit and vegetable juices, vinegar, and water, demonstrating the CDs’ reliability and practicality as a pH sensor in diverse environments. Additionally, the integration of these CDs into a paper strip enabled straightforward and visible-light-based monitoring of seafood freshness, like fish and shrimp. This work offers a cost-effective and sensitive platform for pH detection applications in different fields.

A surface-enhanced Raman scattering (SERS) sensor of Au/Ag nanoparticles (NPs) grown on ZnO/polypyrrole@Poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonate) (PPy@PEDOT:PSS) film for detecting norfloxacin (NFX) residues in milk is presented. The ZnO/PPy@PEDOT:PSS film was prepared by the electrochemical deposition method. Subsequently, Ag NPs and Au NPs were deposited on the surface of ZnO/PPy@PEDOT:PSS film to form a Au/Ag/ZnO/PPy@PEDOT:PSS film by an electrochemical deposition process and the magnetron sputtering process, respectively. Owing to the charge transfer between the SERS substrate and the NFX molecules, this SERS sensor could effectively identify low-concentration NFX molecules with a limit of detection (LOD) of 0.84 nM. Moreover, it could also recognize NFX residues in milk with recoveries of 91.2% to 108.4%. The SERS sensor of Au/Ag/ZnO/PPy@PEDOT:PSS film had a high sensitivity, excellent long-term stability, and significant potential in food safety monitoring applications.

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A novel electrochemical aptamer-based biosensor is reported for label-free detection of prostate-specific membrane antigen (PSMA)-positive exosomes in human urine. The platform integrates magnetic nanoparticles functionalized with CD63-specific aptamers (mMNPs) for efficient exosome capture, and screen-printed electrodes (SPEs) modified with carbon nanofibers (CNFs) and immobilized PSMA-specific aptamers for targeted detection. Differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) confirmed the successful stepwise modification of the electrode surface and target recognition. The biosensor demonstrated excellent analytical performance for PSMA protein detection in exosome isolates, with a detection limit of 3 pg/mL and a linear response from 10 to 1400 pg/mL as quantified by ELISA. Specificity was confirmed using exosomes from PSMA-negative PC3 cell cultures and benign samples. Reproducibility and stability tests were conducted using exosomes isolated from the LNCaP cell culture, which confirmed operational robustness. Clinical urine testing showed high agreement with PSMA ELISA results, and urinary creatinine normalization improved data reliability across samples. This dual-aptamer biosensor offers a highly specific, reproducible, and non-invasive strategy for early prostate cancer diagnosis, with strong potential for point-of-care and clinical translation.