Engineering of a Dual-Recognition Ratiometric Fluorescent Nanosensor with a Remarkably Large Stokes Shift for Accurate Tracking of Pathogenic Bacteria at the Single-Cell Level

Abstract

Rapid, accurate, reliable, and risk-free tracking of pathogenic microorganisms at the single-cell level is critical to achieve efficient source control and prevent outbreaks of microbial infectious diseases. For the first time, we report a promising approach for integrating the concepts of a remarkably large Stokes shift and dual-recognition into a single matrix to develop a pathogenic microorganism stimuli-responsive ratiometric fluorescent nanoprobe with speed, cost efficiency, stability, ultrahigh specificity, and sensitivity. As a proof-of-concept, we selected the Gram-positive bacterium Staphylococcus aureus (S. aureus) as the target analyte model, which easily bound to its recognition aptamer and the broad-spectrum glycopeptide antibiotic vancomycin (Van). To improve the specificity and short sample-to-answer time, we employed classic noncovalent π−π stacking interactions as a driving force to trigger the binding of Van and aptamer dual-functionalized near-infrared (NIR) fluorescent Apt-Van-QDs to the surface of an unreported blue fluorescent π-rich electronic carbon nanoparticles (CNPs), achieving S. aureus stimuli-responsive

Recent Advances in Aptasensors For Rapid and Sensitive Detection of Staphylococcus Aureus

“…(B) General design of the vancomycin and aptamer dual-recognition moieties-based ratiometric fluorescent nanoprobe with a remarkably large Stokes shift for ultrafast and accurate management of S. aureus at the single-cell level. Reproduced with permission ( Shen et al, 2020 ). (C) Schematic illustration of the multiplexed luminescence bioassay based on aptamers-modified UCNPs for the simultaneous detection of various pathogenic bacteria.…”

“…Since QDs of different sizes can be excited by the same wavelength and emit different emission peaks, Wang et al achieved the simultaneous detection of Escherichia coli O157:H7, S. aureus and Vibrio parahaemolyticus by modifying different aptamers with QDs of different sizes ( Wang et al, 2020 ). Shen et al constructed a ratiometric FRET-based aptasensor which involves target-induced emission intensity changes at two or more different wavelengths to reduces interference from various target-independent factors ( Shen et al, 2020 ). They employed novel π-electron-rich carbon nanoparticles (CNPs) with high photostability and blue fluorescence as energy donors, and bilayer-modified QDs with aptamers and vancomycin as energy acceptors (Apt-Van-QDs).…”

Biosensors and Point‐of‐Care Devices for Bacterial Detection: Rapid Diagnostics Informing Antibiotic Therapy

“…In their design, Van and S. Aureus specific aptamer dual-functionalized near-infrared (NIR) fluorescent N-acetyl-l-Cysteine cadmium telluride (NAC-CdTe) QDs were bound to the surface of unreported blue fluorescent 𝜋-rich electronic carbon NPs (CNPs) by noncovalent 𝜋−𝜋 stacking interactions (Apt-Van-QDs@CNPs). [97] With this design the blue CNPs acted as the energy donors while the NIR Apt-Van-QDs acted as the energy acceptors; as they were close enough, the phenomenon of FRET was made possible, thereby leading to a blue fluorescence quenching and a clear NIR fluorescence enhancement. Upon incubation with S. Aureus bacteria, this process was hindered, consequently exhibiting a ratiometric fluorescent response characterized by a large Stokes shift of ≈260 nm.…”

“…The high sensitivity of this sensing platform was due to the efficient targeting of the bacteria with the dual-functionalized QDs. [97] Finally, DNA technology has been incorporated in the design of optical biosensors as they are able to provide better sensitivity than nanomaterial or antibody-based transducing elements. Thus, Chang et al designed a graphdiyne-based fluorescent biosensing platform for the detection of Mycobacterium tuberculosis (M. tuberculosis).…”

Dual-detection fluorescent immunochromatographic assay for quantitative detection of SARS-CoV-2 spike RBD-ACE2 blocking neutralizing antibody

“…Because this single signal method is easily affected by interference from various factors unrelated to the target ( Guo et al, 2021 ; Hou et al, 2020 ), the accuracy and sensitivity of quantitative immunochromatographic assays remain unsatisfactory. However, dual-signal ratio bioassays provide higher precision and sensitivity than single-signal measurements ( Park et al, 2020 ; Shen et al, 2020 ; Spring et al, 2021 ). The classical ratiometric fluorescence assay uses one fluorescence intensity change as a reference to standardize the other changes that occur in response to the same analyte at different wavelengths, thereby providing a built-in self-calibration signal readout.…”