Human Neutrophil Elastase Activated Fluorescent Probe for Pulmonary Diseases Based on Fluorescence Resonance Energy Transfer Using CdSe/ZnS Quantum Dots

Abstract

There is an increasing demand for effective noninvasive diagnosis against common pulmonary diseases, which are rising sharply due to the serious air pollution. Human neutrophil elastase (HNE), a typical protease highly involved in pulmonary inflammatory diseases and lung cancer, is a potential predictor for disease progression. Currently, few of the HNE-targeting probes are applicable in vivo due to the limitation in sensitivity and biocompatibility. Herein, we reported the achievement of in vitro detection and in vivo imaging of HNE by incorporating the HNE-specific peptide substrate, quantum dots (QDs), and organic dyes into the fluorescence resonance energy transfer (FRET) system. The refined nanoprobe, termed QDP, could specifically measure the HNE with excellent sensitivity of 7.15 pM in aqueous solution and successfully image the endogenous and exogenous HNE in living cells. In addition, this nanoprobe enabled HNE imaging in mouse models of lung cancer and acute lung injury, and the HNE activity at high temporal and spatial resolution was continuously monitored. Most importantly, QDP successfully discriminated the serums of patients with lung diseases from those of the healthy controls based on the HNE activity determination. Overall, this study demonstrates the advantages of a FRET-system-based nanoprobe in imaging performance and provides an applicable tool for in vivo HNE detection and pulmonary disease diagnosis.

Ultrahigh Efficient FRET Ratiometric Fluorescence Biosensor for Visual Detection of Alkaline Phosphatase Activity and Its Inhibitor

“…The linear equation was F 572 / F 427 = −0.5549 + 0.2126 C ALP , and the linear coefficient ( R 2 ) and limit of detection (LOD) were 0.994 and 0.396 U/L, respectively (Figure C). Indeed, the FRET efficiency reached up to 93.2%, which was higher than most reported FRET strategies for sensing , and imaging − (Table S1). Furthermore, the DAP produced in the solution was a yellow substance, and the absorbance value of DAP was in a positive correlation with ALP activity in the range of 0–30 U/L (Figure D–F).…”

Horseradish peroxidase-triggered direct in situ fluorescent immunoassay platform for sensing cardiac troponin I and SARS-CoV-2 nucleocapsid protein in serum

“…The detection limit was 0.19 ng/mL, as calculated from 3σ/S, which was superior to those previously reported assay for cTnI detection ( Table S3 ) ( Liu et al, 2016 ; Wu et al, 2010 , 2017 ; Guo et al, 2019 ; Song et al, 2011 ; Dorraj et al, 2015 ; Zuo et al, 2016 ; Tsaloglou et al, 2014 ; Periyakaruppan et al, 2013 ). Comprehensive consideration of performance, cost, and detection time, our method still showed obvious overall advantages compared with other fluorescence-based methods ( Liu et al, 2020 , Liu et al, 2020 , Liu et al, 2020 ; Jarvenpaa et al, 2012 ; Zhao et al, 2019 ; Liu et al, 2020 , Liu et al, 2020 , Liu et al, 2020 ) ( Table S4 ). To validate the sensing ability and specificity of our sensor toward target antigen cTnI, nonspecific proteins, including alpha fetoprotein, lysozyme, pepsin and trypsin were administrated, and some co-existing reducing species, such as AA, GSH, Cys, as well as metal ions (Fe 3+ , Cu 2+ ) had been added the system for target sensing.…”

“…For example, Shiddiky's group developed an enhanced colorimetric molecular sensor for detecting auto-antibodies by coupling HRP with gold-containing nanoporous iron oxide nanoparticles (Shiddiky et al, 2017). In contrast with colorimetric immunoassay, fluorescence immunoassay has drawn increasing attention owing to the advantages of high sensitivity, fast response, and real-time monitoring ( Murfin et al, 2019 ; Liu et al, 2020 , Liu et al, 2020 , Liu et al, 2020 ; Zhou et al, 2020 ). Yang and his colleagues developed a fluorescent immunoassay for alpha-fetoprotein (AFP) based on fluorescein and p-phenylenediamine ( Yuan et al, 2012 ).…”

Cell‐Based Bio‐Hybrid Delivery System for Disease Treatments

“…The recruitment and infiltration cascade of neutrophils are initiated by the endothelium following the gradient of inflammatory factors like cytokine and chemokine. Therefore, neutrophil is usually taken as an indicator of inflammation and relevant diseases, [ 34–37 ] and has been widely studied as a drug delivery system in recent years. [ 38 ] For example, neutrophil‐based delivery system can cross the blood–brain barrier (BBB) and overcome the blood–brain–tumor barrier (BBTB) for malignant glioma treatment.…”