Fe3O4@Au SERS tags-based lateral flow assay for simultaneous detection of serum amyloid A and C-reactive protein in unprocessed blood sample
SENSORS AND ACTUATORS B-CHEMICAL
Authors: Liu, Xiaoxian; Yang, Xingsheng; Li, Kang; Liu, Haifeng; Xiao, Rui; Wang, Weiyun; Wang, Chongwen; Wang, Shengqi
Abstract
Accurate detection of mutiple biomarkers in unprocessed blood via lateral flow immunoassay (LFA) strips remains challenging. Herein, we reported a novel surface-enhanced Raman scattering (SERS)-based LFA strip for ultrasensitive and simultaneous analysis of dual infection biomarkers by using functionalized Fe3O4@Au magnetic nanoparticles (MNPs). Antibody-modified Fe3O4@Au MNPs were designed as SERS nanotags and efficient enrichment tool. The target infection biomarkers were quickly captured and enriched from the blood sample by Fe3O4@Au nanotags. After washing to remove impurities, Fe3O4@Au nanotags acted as high-performance SERS reporters for quantitative detection of the target in the LFA strip. Through this strategy, the proposed Fe3O4@Au based LFA allowed quantified analysis of target infection biomarkers in unprocessed blood samples with the limits of detection of 0.1 ng/mL and 0.01 ng/mL for serum amyloid A (SAA) and C-reactive protein (CRP), respectively. By comparison, the proposed assay for SAA and CRP was 100-fold and 1000-fold more sensitive than standard colloidal gold strip by using the same antibodies, respectively. This magnetic SERS strip also exhibited excellent stability, specificity, and selectivity for complex samples and could be used as an effective tool for infectious disease diagnostics.
The association between leptin and inflammatory markers with obesity indices in Zanzibari children, adolescents, and adults
OBESITY SCIENCE & PRACTICE
Authors: Nyangasa, Maria Adam; Buck, Christoph; Kelm, Soerge; Sheikh, Mohammed Ali; Guenther, Kathrin; Hebestreit, Antje
Abstract
Background Research from Western populations describes abdominal obesity as a low-grade inflammatory disease; less is known from tropical areas with high pathogen burden. Objectives This cross-sectional study investigated whether obesity contributes to low-grade inflammation in 587 individuals from randomly selected households in Zanzibar. Materials and Methods The Association between obesity indices (body mass index [BMI], waist circumference [WC], and percentage body fat [%BF]), leptin, and inflammatory markers (C-reactive protein [CRP], interleukin-6 [IL-6] and tumor-necrosis factor-alpha [TNF-alpha]) was investigated using multinomial logistic regression analysis, accounting for ordinal outcome variables with four categories; 1st-4th quartile. Results Study participants were between 5 and 95 years; 49.6% were male. Mean serum levels were; leptin: 4.3 +/- 5.2 ng/ml, CRP: 0.19 +/- 0.42 mu g/ml, IL-6: 2.8 +/- 5 pg/ml, and TNF-alpha: 5.3 +/- 5.2 pg/ml. Obesity indices were associated with leptin and CRP in the third and fourth quartiles in single models. In combined models, associations were observed between BMI (OR = 6.36 [95% CI, 1.09; 34.12]); WC (OR = 4.87 [95% CI, 1.59; 14.94]); and %BF (OR = 19.23 [95% CI, 4.70; 78.66]) and leptin in the fourth quartile; also between %BF and CRP in the third quartile (OR = 3.49 [95% CI 1.31; 9.31]). Conclusion Total body fat was associated with low-grade inflammation in this tropical population rather than body fat distribution such as abdominal obesity. This may increase the risk of insulin resistance and other obesity-related metabolic and cardiovascular health endpoints.