Dual-triggered nanoaggregates of cucurbit[7]uril and gold nanoparticles for multi-spectroscopic quantification of creatinine in urinalysis

Abstract

A novel nanosensing platform was developed for the quantitative detection of creatinine of clinically relevant concentrations via UV-Vis spectroscopy and surface-enhanced Raman spectroscopy.

Quantitative SERS Detection of Uric Acid via Formation of Precise Plasmonic Nanojunctions within Aggregates of Gold Nanoparticles and Cucurbit[<em>n</em>]uril

“…Further characterization can be performed to elucidate the fundamental property of the CB complexes. For instance, the formation of host-guest complexes can typically be confirmed using 1 H nuclear magnetic resonance (NMR), which should show upfield shift and broadening of signals in case of complexation 21,22,25 . Yet 1 H NMR is not applicable to UA due to its lack of nonexchangeable protons.…”

“…Alternative techniques such as 13 C NMR and mass spectrometry could also be employed to characterize the complexation. Binding constants between CB7 and UA can be measured using titration techniques, such as UV-Vis spectroscopy titration and isothermal titration calorimetry (ITC) 21,22,25 . Meanwhile molecular modelling based on force-field and density functional theory (DFT) models can be computed to obtain theoretical insights into the binding geometry of the host-guest complexes 21,22,25,29 .…”

“…Binding constants between CB7 and UA can be measured using titration techniques, such as UV-Vis spectroscopy titration and isothermal titration calorimetry (ITC) 21,22,25 . Meanwhile molecular modelling based on force-field and density functional theory (DFT) models can be computed to obtain theoretical insights into the binding geometry of the host-guest complexes 21,22,25,29 . Moreover IR and Raman spectra can be computed by frequencies calculations 21,25,29 .…”

“…Meanwhile molecular modelling based on force-field and density functional theory (DFT) models can be computed to obtain theoretical insights into the binding geometry of the host-guest complexes 21,22,25,29 . Moreover IR and Raman spectra can be computed by frequencies calculations 21,25,29 . SERS is a highly sensitive and selective analytical technique which allows identification of trace analytes via their molecule-specific vibrational fingerprints.…”

“…Attachment of macrocyclic molecules, cucurbit[n]urils (CBn, where n = 5-8, 10), onto the surface of Au NPs can further enhance the SERS signals of the analyte molecules as the highly symmetric and rigid CB molecules can control the precise spacing between the Au NPs and localize the analyte molecules at the center or in close proximity to the plasmonic hotspots via formation of host-guest complexes (Figure 1) [17][18][19][20] . Previous examples of SERS studies using Au NP: CBn nanoaggregates include nitroexplosives, polycyclic aromatics, diaminostilbene, neurotransmitters and creatinine [21][22][23][24][25] , with the SERS measurements either being performed in a cuvette or by loading a small droplet onto a custommade sample holder. This detection scheme is particularly useful to rapidly quantify biomarkers in a complex matrix with a high reproducibility.…”