Gold nanocluster-encapsulated glucoamylase as a biolabel for sensitive detection of thrombin with glucometer readout

The Personal Glucose Meter as the Measurement Principle in Point-of-Care Applications

A personal glucose meter (PGM) is a medical device that measures blood glucose levels and can be found worldwide. Owing to their sensitivity, simplicity, portability, and low cost, PGMs stand as one of the most frequently utilized analytical methods. This work reviews the different applied methodologies for detecting analytes other than glucose employing a PGM and how it can be incorporated for point-of-care diagnosis needs. To visualize the variants, first, a classification is made according to the biorecognition elements used (aptamers, antibodies, etc.), and where the determination of different analytes is done through the glucose signal using different glucose-generating enzymes such as invertase or glucosidase. Transduction can also be based on the use of nanocarriers that generally encapsulate glucose, although it is also possible to find a combination of the two aforementioned strategies. The PGM can also be used for the direct detection of interfering substances of the biosensor, such as NADH or paracetamol. Lastly, we discuss how a PGM might have been implemented to detect COVID-19 and how it could be used on a massive scale for the point-of-care diagnosis of a pandemic.

Size and shape trump charge in interactions of oxovanadates with self-assembled interfaces: application of continuous shape measure analysis to the decavanadate anion

Using ⁵¹V NMR spectroscopy, dynamic light scattering and continuous shape analysis to characterize two polyoxometalate-encapsulation in reverse micelles.

Exonuclease III-based target recycling for ultrasensitive homogeneous monitoring of HIV DNA using Ag(+)-coordinated hairpin probe

A new homogeneous electrochemical sensing strategy based on exonuclease III-assisted target recycling amplification was utilized for simple, rapid and highly sensitive detection of human immunodeficiency virus (HIV) DNA on an immobilization-free Ag(I)-assisted hairpin DNA through the cytosine-Ag(+)-cytosine coordination chemistry. The assay involved target-induced strand-displacement reaction accompanying dissociation of the chelated Ag(+) in the hairpins and exonuclease III-triggered target recycling. Initially, the added target DNA hybridized with hairpin DNA to disrupt the Ag(I)-coordinated hairpin probe and releases the coordinated Ag(+) ion. Then, the newly formed DNA double-stranded DNA could be cleaved by exonuclease III, and released target HIV DNA, which retriggered the strand-displacement reaction with the hairpin for target recycling, thereby resulting in formation of numerous free Ag(+) ions in the detection cell. The released Ag(+) ions can be readily captured by the negatively charged electrode, and subsequent anodic-stripping voltammetric detection of the captured Ag(+) ions are conducted to form the anodic current for the production of the electronic signal within the applied potential. Under optimal conditions, the exonuclease III-based sensing system exhibited good electrochemical responses for the detection of HIV DNA at a concentration as low as 23 fM.

Sensitive electrochemical immunoassay with signal enhancement based on nanogold-encapsulated poly(amidoamine) dendrimer-stimulated hydrogen evolution reaction

A new electrochemical immunosensor with signal enhancement was designed for sensitive detection of disease-related protein (human carbohydrate antigen 19-9, CA 19-9 used in this case).

Glutathione-directed synthesis of luminescent Ag2S nanoclusters as nanosensors for copper(ii) ions and temperature

Highly red luminescent Ag₂S nanoclusters were synthesized and they show higher sensitivity as nanosensors for copper(ii) ion and temperature.