Ultra-sensitive detection of ATP in serum and lysates based on nitrogen-doped carbon dots

An abiotic carbon dots@ ZIF-90 fluorescent probe for rapid and reliable detection of adenosine triphosphate

ATP is a high-energy compound that plays a vital role in biological metabolism. Abnormal changes in ATP concentration are related to various diseases and reflect microbial metabolism in biofilms. In this work, we prepared carbon quantum dots (CDs) with aggregation-induced fluorescence inhibition effect using the bacterial culture medium as raw material with a hydrothermal method. Then, an abiotic fluorescent nanoprobe named CDs@zeolitic imidazolate frameworks-90 (ZIF-90) was facilely synthesized by encapsulating CDs into ZIF-90. Owing to the encapsulation of CDs in the hollow structure of ZIF-90, the blue fluorescence emission of CDs@ZIF-90 decreased significantly. In the presence of ATP, the ZIF-90 framework was destroyed due to the strong coordination between ATP and Zn²⁺. The released CDs exhibited stronger fluorescence intensity, which was closely related to the ATP concentration. The convenient synthesis process and rapid ATP-responsive ability make CDs@ZIF-90 highly promising for clinical and environmental analysis.

Metal ions mediated carbon dots nanoprobe for fluorescent turn-on sensing of N-acetyl-L-cysteine

Carbon dots (CDs) was facilely synthesized from aspartic acid through a pyrolysis method in this work. Based on their favorable fluorescence property, CDs was utilized to design a metal ions-mediated fluorescent probe for N-acetyl-L-cysteine (NAC) detection. The fluorescence intensity of CDs was firstly quenched by manganese ion (Mn²⁺ ) through static quenching effect and subsequently restored by NAC via the combination with Mn²⁺ owing to the coordination effect. Therefore, the fluorescent turn-on sensing of NAC was actuated based on the fluorescence quenching stimulated by Mn²⁺ and recovery induced by coordination. The fluorescence recovery efficiencies showed a proportional range to the concentration of NAC in the range of 0.04-5 mmol L^-1 and the detection limit was 0.03 mmol L^-1 . Further, this metal ions-mediated fluorescent nanoprobe was applied to human urine sample detection and the standard recovery rates were located in the range of 97.62-102.34 %. It was the first time that Mn²⁺ was used to construct fluorescent nanoprobe for NAC. Compared to other heavy metal ions, Mn²⁺ with good biosecurity prevented the risk of application, which made the nanoprobe green and bio-practical. The facile synthesis of CDs and novel metal ions-mediated sensing mode made it a promising method for pharmaceutical analysis.