Nitrogen-doped Carbon Dots Mediated Fluorescent on-off Assay for Rapid and Highly Sensitive Pyrophosphate and Alkaline Phosphatase Detection

Abstract

In this report, a novel fluorescent sensing platform using nitrogen-doped carbon dots (N-CDs) as probes for fluorescence signal transmission has been designed for the detection of significant biomolecules pyrophosphate (PPi) and alkaline phosphatase (ALP). The high fluorescent N-CDs could be selectively quenched by Cu2+, and recovered by the addition of PPi because PPi preferentially binds to Cu2+. Once ALP was introduced into the system, ALP can specifically hydrolyze PPi into Pi, the intense fluorescence of N-CDs could be quenched again due to the recombination of the as-released Cu2+ with N-CDs. So, fluorescence of N-CDs is regulated by an ALP-triggered reaction. Based on this strategy, we demonstrated that N-CDs could serve as a very effective fluorescent sensing platform for label-free, sensitive and selective detection of PPi and ALP with low detection limit of 0.16 μM and 0.4 U/L for PPi and ALP, respectively. Moreover, the assay time is just around 0.5 min for PPi and 30 min for ALP. This developed strategy shows remarkable advantages including sensitive, rapid, simple, convenient, and low-cost and so forth. Furthermore, this method was also successfully applied to monitor ALP in human serum, which indicates its great potential for practical applications in biological and clinical diagnosis.

Nitrogen-Doped Carbon Quantum Dots as Fluorescent Probes for Sensitive and Selective Detection of Nitrite

“…Carbon quantum dots (CQDs) are small nanoparticles (less than 10 nm diameter) [ 19 ]. They were found to exhibit photoluminescent properties when first discovered accidentally by Xu et al in 2004 [ 20 ].…”

Overview of Optical and Electrochemical Alkaline Phosphatase (ALP) Biosensors: Recent Approaches in Cells Culture Techniques

“…Increased fluorescence intensity during high-level ALP expression provides a rapid and non-toxic method for cellular detection of ALP activity. Hu et al (2017) proposed a new fluorescent sensing platform that uses nitrogen-doped carbon dots (N-CDs) as a probe for fluorescence signal transmission for ALP and PPi [144]. Cu 2+ quench high fluorescent N-CDs and can be recovered when PPi is added since PPi binds to Cu 2+ .…”

Smart probe for simultaneous detection of copper ion, pyrophosphate, and alkaline phosphatase in vitro and in clinical samples

“…Such a combined detection scheme has already developed before making use of different kinds of nanoparticles. More specifically, Mo oxide quantum dots [40], carbon dots [41–43], Au nanoclusters [44], carbon dots and Au nanoclusters [45], silver nanocluster [46], upconversion nanoparticle [47], Eu(DPA)3@Lap nanohybrid material [48], or anionic conjugated polymers [49] were utilized. Several of these have superior sensitivity.…”