Sandwich-type Surface Stress Biosensor Based on Self-Assembled Gold Nanoparticles in PDMS Film for BSA Detection

A mechanical biosensor based on membrane-mediated magneto-stress-electric coupled sensitization for human serum albumin detection

Recently, mechanical biosensors have attracted more attention on single molecule detection due to its high accuracy, low cost, and convenience. However, the sensitivity of the mechanical biosensors restricted their clinical application. Herein, a mechanical biosensor based on membrane-mediated magneto-stress-electric coupled sensitization (MSEC-MMB) was developed to enhance performance. Through introducing Fe3O4 nanoparticles (MNPs) to traditional stress-electric biosensors and applying a magnetic field, a magneto-stress-electric coupled biosensing system was constructed. The sensitivity of the MSEC-MMB was improved via enhancing the deformation of the mechanical membrane, which was demonstrated by detecting HSA. The optimal limit of detection (LOD) was 24 pg mL-1 under a magnetic field of 50 mT. The LOD was significantly 1 order of magnitude lower than that without the magnetic field. Besides, the MSEC-MMB showed a high specificity, selectivity, and stability. The clinical proteinuria samples were accurately detected, suggesting a good practicability of the MSEC-MMB. All these results proved the high sensitivity and practicality of the MSEC-MMB and provide a platform for early nephropathy diagnosis.

Multilayer Heterogeneous Membrane Biosensor Based on Multiphysical Field Coupling for Human Serum Albumin Detection

A factor closely associated with renal disease status in clinical diagnosis is abnormal human serum albumin (HSA) concentration levels in human body fluids urine, serum, etc. The surface stress biosensor was developed as a new type of biosensor to detect protein molecule concentration and has a wide range of clinical applications. However, further sensitivity improvement is required to achieve higher detection performance. Herein, MXene/PDMS/Fe₃O₄/PDMS of the multilayer heterogeneous membrane biosensor (MHBios) based on the coupling of the magnetic field, electric field, and surface stress field was successfully developed to achieve high sensitivity HSA detection through magnetic sensitization. The modified antibody specifically binds to HSA at the AuNP layer, allowing the biosensor to convert the surface stress caused by PDMS film deformation into an electrical signal. When the biosensor was exposed to a uniform magnetic field, the conductive path of the conductive layer was reshaped further as the magnetic force amplified the deformation of the PDMS film, enhancing the conversion of biological signals to electrical signals. The results exhibited that the detection limit (LOD) of the MHBios was 78 ng/mL when HSA concentration was 0-50 μg/mL, which was markedly lower than the minimum diagnostic limit of microalbuminuria. Furthermore, the MHBios detected HSA in actual samples, confirming the potential for early disease screening.

The synthesis and application of a colour-switch β-arylethenesulfonyl fluoride fluorescent probe in the detection of serum albumin

Proteins play a pivotal role in regulating important physiological processes and serve as important biomarkers for many diseases. Herein, we present a new strategy for bovine serum albumin (BSA) detection using a novel colour-switch fluorescent probe CPV-ESF ((E)-2-(4-((Z)-1-cyano-2-(4-(diethylamino)phenyl)vinyl)phenyl)ethene-1-sulfonyl fluoride). CPV-ESF reacts with nucleophilic amino acids of BSA via 1,4-Michael addition click chemistry to create a covalently linked CPV-ESF:BSA complex, which can be easily detected by a fluorescence colour-switch response. The sensing mechanism, sensitivity and selectivity of CPV-ESF for BSA detection as well as its application for cell imaging have been investigated.