ABSTRACT
Three functional magnetic nanocatalytic probe, which integrates recognition, catalytic amplification, and separation enrichment, is a new approach to construct a simple, fast, highly selective, and sensitive analytical method. In this article, a new magnetic nanosurface molecularly imprinted polymer nanoprobe (Fe3O4@MIP) with trifunctionality was rapidly prepared using a microwave-assisted method with magnetic Fe3O4 nanoparticles as a substrate, chloramphenicol (CAP) as a template molecule, and methacrylic acid as a functional monomer. The characterized nanoprobe was found that could specifically recognize CAP, strongly catalyze the new indicator nanoreaction of fructose (DF)-HAuCl4. The gold nanoparticles (AuNPs) exhibit strong resonance Rayleigh scattering (RRS) and surface enhanced Raman scattering (SERS) effects. Upon addition of CAP, the SERS/RRS signals were linearly weakened. Accordingly, a new SERS/RRS analysis platform for highly sensitive and selective determination of CAP was constructed. The SERS linear range was 0.0125-0.1 nmol/L, with detection limit (DL) of 0.004 nmol/L CAP. Furthermore, it could be combined with magnet-enriched separation to further improve the sensitivity, with a DL of 0.04 pmol/L CAP. The SERS method has been used for the determination of CAP in real samples, with relative standard deviations of 2.37-9.89 % and the recovery of 95.24-107.1 %.
ABSTRACT
Background: Metabolic syndrome (MetS) has attracted great interest, with an increasing prevalence. Recent studies have shown that the serum uric acid-to-creatinine ratio (SUACr) might be an excellent biomarker for MetS risk prediction in diabetic patients and postmenopausal women. However, the relationship between SUACr and MetS in a middle-aged and older population remains unclear. Methods: A total of 1277 participants were included in this cross-sectional study. Logistic regression modelling was performed to assess the association between SUACr and MetS in the total population. The dose-response relationship of SUACr and MetS was further assessed by a restricted cubic spline model (RCS). Furthermore, to explore the relationships between the levels of SUACr and the number of metabolic components, analysis of covariance (ANCOVA) was applied. Results: The levels of SUACr were lower in the non-MetS participants (OR 1.60, 95% CI 1.36 to 1.89; P<0.001),. Positive and dose-response relationships were further confirmed by the RCS model. We also found that, with increased number of components, the SUACr tended to increase. Moreover, values of SUACr were strongly related to levels of triglycerides (TGs), body mass index (BMI), blood glucose levels, systolic blood pressure/diastolic blood pressure (SBP/DBP), and hypertension. In addition, the positive association between SUACr and MetS also occurred in those patients with normal uric acid levels. Conclusion: Elevated values of SUACr were strongly associated with an increased risk of MetS; this positive relationship remained in those individuals with normal uric acid levels.
