Aptamer Turn-On SERS/RRS/Fluorescence Tri-mode Platform for Ultra-trace Urea Determination Using Fe/N-Doped Carbon Dots

Abstract

Sensitive and selective methods for the determination of urea in samples such as dairy products are important for quality control and health applications. Using ammonium ferric citrate as a precursor, Fe/N-codoped carbon dots (CDFeN) were prepared by a hydrothermal procedure and characterized in detail. CDFeN strongly catalyzes the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2 to turn on an indicator molecular reaction, forming an oxidized tetramethylbenzidine (TMBox) probe with surface-enhanced Raman scattering, resonance Rayleigh scattering, and fluorescence (SERS, RRS, and FL) signals at 1,598 cm−1, 370 nm, and 405 nm, respectively. The urea aptamer (Apt) can turn off the indicator reaction to reduce the tri-signals, and the addition of urea turns on the indicator reaction to linearly enhance the SERS/RRS/FL intensity. Thus, a novel Apt turn-on tri-mode method was developed for the assay determination of ultra-trace urea with high sensitivity, good selectivity, and accuracy. Trace adenosine triphosphate and estradiol can also be determined by the Apt-CDFeN catalytic analytical platform.

Portable, multi-modal Raman and fluorescence spectroscopic platform for point-of-care applications

“…Most of the previous work within the scope of dual Raman and fluorescence detection applications is centered around endoscopic/imaging approaches for spatial localization within diseased tissues, detection of DNA or RNA sequences, and environmental monitoring. 38 – 46 , 55 – 57 The imaging applications typically utilize fluorescence labeling to determine the general location of target biomarkers within a larger field of view, and the Raman detection is used to discriminate between healthy and diseased regions of interest. The DNA and RNA detection applications focus on developing novel particles, substrates, and sensing schemes to improve detection sensitivity.…”

“…The development of dual Raman and fluorescence active sensing probes are well documented in the literature. 38 – 46 However, to our knowledge, no commercially available small form factor multimodal spectrometer combines the benefits of fluorescence and Raman for POC monitoring. The spectroscopic platform proposed here integrates the excitation and collection optics into a single portable package with the flexibility to collect signals from a solid surface or liquid interface.…”

Recent Advances in the DNA-Mediated Multi-Mode Analytical Methods for Biological Samples

“…Integrating DNA structure to construct accurate, selective, sensitive and efficient multi-mode nanoprobes will improve the anti-interference capability, specificity, sensitivity and accuracy of multi-mode analytical methods, as well as the detection throughput [29][30][31]. At present, common DNA-mediated multi-mode analytical methods include surface-enhanced Raman scattering (SERS)/FL [32], SERS/colorimetric [33], FL/colorimetric [34], FL/photothermal (PT) [35] and SERS/electrochemistry (EC) [36], SERS/FL/colorimetric [37], SERS/resonant Rayleigh scattering (RRS)/FL [38] methods, etc. It has become a popular research interest to utilize the characteristics of DNA to design sensitive, reliable and efficient multi-mode DNA-mediated analytical methods in recent years.…”

Nanogold sol plasmon discattering assay for trace carbendazim in tea coupled aptamer with Au3+-glyoxal-carbon dot nanocatalytic reaction

“…Similarly, a non-pretreatment SERS detection was completed by using a plasma platform functionalized (16). To improve the selectivity and detection range, some selective bioreactions such as Apt and peptide were used in SERS (17)(18)(19). Yang et al ( 20) established an Apt-SERS sensor for the highly selective detection of thrombin, combining the nanocatalyzed SERS reaction of gold nanoparticles (AuNPs) on HAuCl 4 -H 2 O 2 with the Apt reaction, which could effectively detect the concentration range of 0.13-53.33 nmol/L Pb 2+ .…”