Electrochemically driven optical and SERS immunosensor for the detection of a therapeutic cardiac drug

Ultrasensitive detection of vital biomolecules based on a multi-purpose BioMEMS for Point of care testing: digoxin measurement as a case study

Rapid and label-free detection of very low concentrations of biomarkers in disease diagnosis or therapeutic drug monitoring is essential to prevent disease progression in Point of Care Testing. For this purpose, we propose a multi-purpose optical Bio-Micro-Electro-Mechanical-System (BioMEMS) sensing platform which can precisely measure very small changes of biomolecules concentrations in plasma-like buffer samples. This is realized by the development of an interferometric detection method on highly sensitive MEMS transducers (cantilevers). This approach facilitates the precise analysis of the obtained results to determine the analyte type and its concentrations. Furthermore, the proposed multi-purpose platform can be used for a wide range of biological assessments in various concentration levels by the use of an appropriate bioreceptor and the control of its coating density on the cantilever surface. In this study, the present system is prepared for the identification of digoxin medication in its therapeutic window for therapeutic drug monitoring as a case study. The experimental results represent the repeatability and stability of the proposed device as well as its capability to detect the analytes in less than eight minutes for all samples. In addition, according to the experiments carried out for very low concentrations of digoxin in plasma-like buffer, the detection limit of LOD = 300 fM and the maximum sensitivity of S = 5.5 × 1012 AU/M are achieved for the implemented biosensor. The present ultrasensitive multi-purpose BioMEMS sensor can be a fully-integrated, cost-effective device to precisely analyze various biomarker concentrations for various biomedical applications.

Overview of therapeutic drug monitoring and clinical practice

With the rapid development of clinical pharmacy in China, therapeutic drug monitoring (TDM) has become an essential tool for guiding rational clinical drug use and is widely concerned. TDM is a tool that combines pharmacokinetic and pharmacodynamic knowledge to optimize personalized drug therapy, which can improve treatment outcomes, reduce drug-drug toxicity, and avoid the risk of developing drug resistance. To effectively implement TDM, accurate and sophisticated analytical methods are required. By researching the literature published in recent years, we summarize the types of commonly monitored drugs, therapeutic windows, and clinical assays and track the trends and hot spots of therapeutic drug monitoring. The purpose is to provide guidelines for clinical blood drug concentration monitoring, to implement individualized drug delivery programs better, to ensure the rational use of drugs for patients, and to provide a reference for the group to carry out related topics in the future.

CRISPR/Cas12a-Powered Competitive Immunosorbent Assay for Small Molecules

CRISPR/Cas systems are powerful tools for sensitive nucleic acid molecular diagnosis due to their specific nucleic acid recognition and high trans-cleavage activity and have also allowed for quantification of non-nucleic acid targets, relying on a strategy to convert the target detection to analysis of nucleic acids. Here, we describe a CRISPR/Cas12a-powered immunosorbent assay for sensitive small-molecule detection by using the antibody coated on the microplate to recognize the target and the small molecule-labeled active DNA (acDNA) to trigger the activity of CRISPR/Cas12a. In the absence of small-molecule targets, acDNA probes are captured by the antibody on the microplate and then activate Cas12a in catalytic trans-cleavage of fluorescent DNA reporters, generating strong fluorescence. The presence of small-molecule targets displaces the acDNA probes from the antibody, causing a decrease of acDNA probes on the microplate and reduction of activated Cas12a, so the fluorescence signal decreases, and small molecules can be detected by monitoring the fluorescence change. After systematically optimizing experimental conditions (e.g., Cas12a reaction), the proposed method achieved the detection of three model small molecules, biotin, digoxin, and folic acid, with low detection limits, and a flexible detection concentration range was obtained by simply changing the amount of acDNA probes and immobilized antibodies. The assay showed high selectivity and good applicability in complex media. The integration of the CRISPR/Cas12a system improves the analytical performance of immunoassay, broadening and facilitating its applications in rapid, simple, and sensitive small molecule analysis.