Am T‐Stück angesetzt: Poly‐T‐Einzelstrang‐DNA (blau, siehe Schema) dient als Templat für die Bildung fluoreszierender Kupfernanopartikel (CuNPs, rote Kugeln). Größe und Fluoreszenz der CuNPs sind über die Länge der Poly‐T‐Sequenz einstellbar. Andere Einzelstrang‐DNAs (grün) sind keine geeigneten Template für CuNPs und können daher zum Aufbau von Nanostrukturen mit wechselnden metallierten und nichtmetallierten Bereichen genutzt werden.
Measuring the levels of Fe in human body has attracted considerable attention for health monitoring as it plays an essential role in many physiological processes. In this work, we reported a selective fluorescent nanoprobe for Fe detection in biological samples based on ultrabright N/P codoped carbon dots. By employing adenosine 5'-triphosphate (ATP) as the carbon, nitrogen, and phosphorus source, the N/P codoped carbon dots could be simply prepared through hydrothermal treatment. The obtained carbon dots exhibited high quantum yields up to 43.2%, as well as excellent photostability, low toxicity, and water solubility. Because of the Fe-O-P bonds formed between Fe and the N/P codoped carbon dots, this nanoprobe showed high selectivity toward Fe against various potential interfering substances in the presence of EDTA. The fluorescence quenching of as-fabricated carbon dots was observed with the increasing Fe concentration, and the calibration curve displayed a wide linear region over the range of 1-150 μM with a detection limit of 0.33 μM. The satisfactory accuracy was further confirmed with the river samples and ferrous sulfate tablets, respectively. With the above outstanding properties, these N/P codoped carbon dots were successfully applied for direct detection of Fe in biological samples including human blood serum and living cells. As compared to the most reported carbon dots-based Fe sensors, this nanoprobe showed high fluorescence, good accuracy, and excellent selectivity, which presents the potential practical application for diagnosis of Fe related disease.
An intramolecular catalytic hairpin assembly is implemented on a DNA tetrahedron for mRNA imaging in living cells. The spatial confinement effect enables the acceleration of target-triggered signal generation, with excellent cell permeability and FRET signal stability.
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The infection and spread of pathogens (e.g., COVID-19) pose an enormous threat to the safety of human beings and animals all over the world. The rapid and accurate monitoring and determination of pathogens are of great significance to clinical diagnosis, food safety and environmental evaluation. In recent years, with the evolution of nanotechnology, nano-sized graphene and graphene derivatives have been frequently introduced into the construction of biosensors due to their unique physicochemical properties and biocompatibility. The combination of biomolecules with specific recognition capabilities and graphene materials provides a promising strategy to construct more stable and sensitive biosensors for the detection of pathogens. This review tracks the development of graphene biosensors for the detection of bacterial and viral pathogens, mainly including the preparation of graphene biosensors and their working mechanism. The challenges involved in this field have been discussed, and the perspective for further development has been put forward, aiming to promote the development of pathogens sensing and the contribution to epidemic prevention.
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