Rapid FRET-based homogeneous immunoassay of procalcitonin using matched carbon dots labels

Abstract

A novel method for the detection of procalcitonin in a homogeneous system by matched carbon dots (CDs) labeled immunoprobes was proposed based on the principle of FRET and double antibody sandwich method. Blue-emitting carbon dots with a strong fluorescence emission range of 400–550 nm and red-emitting carbon dots with the best excitation range of 410–550 nm were prepared before they reacted with procalcitonin protoclone antibody pairs to form immunoprobes. According to the principles of FRET, blue-emitting carbon dots were selected as the energy donor and red-emitting carbon dots as the energy receptor. The external light source excitation (310 nm) could only cause weak luminescence of CDs. However, once procalcitonin was added, procalcitonin and antibodies would be combined with each other quickly (≤20 min). Here, blue-emitting carbon dots acquired energy could be transferred to red-emitting carbon dots efficiently, causing the emitted fluorescence enhancement of red-emitting carbon dots. The fluorescence detection results in PBS buffer solution and diluted rabbit blood serum showed that the fluorescence intensity variation was linear with the concentration of procalcitonin. There was a good linear relationship between F/F0 and procalcitonin concentrations in PBS buffer solution that ranged from 0 to 100 ng ml−1, and the linear equation was F/F0 = 0.004 * C pct + 0.98359. Detection in the diluted rabbit serum led to the results that were linear in two concentration ranges, including 0–40 ng ml−1 and 40–100 ng ml−1, and the detection limit based on 3σ K−1 was 0.52 ng ml−1. It is likely that this matched CDs labeled immunoprobes system can provide a new mode for rapid homogeneous detection of disease markers.

Microwave synthesized novel biomass carbon dots applied in the fluorescent detection of crystal violet

“…Thus, the IFE or FRET was thought to be the quenching mechanism [43]. The difference between IFE and FRET is that FRET occurs with a decay of the fluorescence lifetime of the fluorescence donor, whereas IFE does not accompany with this phenomenon [44,45]. In order to further determine the quenching mechanism, the fluorescence lifetimes of CDs before and after CV addition were determined in Figure 5c, and the average lifetime of CDs was 3.97 ns without CV and 3.93 ns in the presence of CV, which verified that the fluorescence lifetime of CDs did not change.…”

Progress in Procalcitonin Detection Based on Immunoassay

“…This strategy enables trace-level quantification of PCT within a detection range of 1 to 1,000 pg/ml (Fig. 7 D) [ 70 ]. In PCT detection, paired mouse mAbs were usually used to bind to 2 different antigen binding sites, thereby forming a sandwich complex.…”

“…Copyright 2022 American Chemical Society. (D) Preparation of immunofluorescent nanocapsules and immunomagnetic carbon dots and 2 sensing systems for PCT detection [ 70 ]. Copyright 2023 Elsevier.…”

Nanotechnology in inflammation: cutting-edge advances in diagnostics, therapeutics and theranostics

“…CDs are versatile fluorescent nanomaterials prized for their adjustable luminescence and excellent biocompatibility in biosensing applications 95 . Immunomagnetic CDs are a class of carbon-based nanomaterials that integrate magnetic functionalities and specific antibodies 95 .…”

“…CDs are versatile fluorescent nanomaterials prized for their adjustable luminescence and excellent biocompatibility in biosensing applications 95 . Immunomagnetic CDs are a class of carbon-based nanomaterials that integrate magnetic functionalities and specific antibodies 95 . They are valuable in analytical chemistry and biosensing due to their ability to recognize and isolate specific targets efficiently without complex sample preparation procedures 95 .…”