Ultrasensitive Fluorometric Angling Determination of Staphylococcus aureus in Vitro and Fluorescence Imaging in Vivo Using Carbon Dots with Full-Color Emission

Abstract

Rapid, accurate, and safe screening of foodborne pathogenic bacteria is essential to effectively control and prevent outbreaks of foodborne illness. Fluorescent sensors constructed from carbon dots (CDs) and nanomaterial-based quenchers have provided an innovative method for screening of pathogenic bacteria. Herein, an ultrasensitive magnetic fluorescence aptasensor was designed for separation and detection of Staphylococcus aureus (S. aureus). Multicolor fluorescent CDs with a long fluorescent lifetime (6.73 ns) and high fluorescence stability were synthesized using a facile hydrothermal approach and modified cDNA as a highly sensitive fluorescent probe. CD fluorescence was quenched by Fe3O4 + aptamer via fluorescence resonance energy transfer (FRET). Under optimal conditions, the FRET-based aptasensor can detect S. aureus accompanied by a wide linear range of 50–107 CFU·mL–1 and a detection limit of 8 CFU·mL–1. Compared with other standard methods, this method was faster and more convenient, and the entire test was finished within 30 min. The capability of the aptasensor was simultaneously investigated on food samples. Additionally, the developed CDs exhibited excellent biocompatibility and were thus applied as fluorescent probes for bioimaging both in vitro and in vivo. This new platform provided an excellent application of the CDs for detecting and bioimaging pathogenic bacteria.

Green Synthesis of Full-Color Fluorescent Carbon Nanoparticles from Eucalyptus Twigs for Sensing the Synthetic Food Colorant and Bioimaging

“…This phenomenon could be related to the sizes obtained for different CNPs, based on the quantum confinement effect. 61 …”

Harnessing versatile dynamic carbon precursors for multi-color emissive carbon dots

“…Because CDs have good stability and low biological toxicity, they can be used for in vitro cell imaging and in vivo tumor tissue imaging. 232 Moreover, the water-soluble phosphorescent carbon nanodots (CNDs) with high stability and good biocompatibility prepared by Shan et al could be used as afterglow agents for afterglow imaging for in vivo / in vitro bio-imaging. 233…”

Carbon dot composites for bioapplications: a review

“…9A–D). 255 In a different study, Lu and co-workers injected dopamine–CD composites into the back of a mouse and a strong fluorescence signal was observed when excitation and emission wavelengths were 540 and 600 nm, respectively. 201 Among the CD composites applied for in vivo fluorescence imaging, there are also many reports on N-doped CDs.…”

“…For instance, in Yan and co-workers’ study, glyoxylic acid-modified CDs (GA-CDs) were used as a FRET ratiometric fluorescent probe for the detection of Cu 2+ in aqueous solution. 388 Similarly, Chen et al also applied cyclam-functionalized CDs as a FRET nanoprobe for the detection of Cu 2+ and S. 2–389 In addition to the above examples, the detection of other important metal ions such as Ag + , Cu 2+ , Cr 6+ , and Pb 2+ has also been successfully realized with CD composite-based sensing platforms. 390–401…”