Aggregated silver nanoparticles based surface-enhanced Raman scattering enzyme-linked immunosorbent assay for ultrasensitive detection of protein biomarkers and small molecules.
Lowering the detection limit is critical to the design of bioassays required for medical diagnostics, environmental monitoring, and food safety regulations. The current sensitivity of standard color-based analyte detection limits the further use of enzyme-linked immunosorbent assays (ELISAs) in research and clinical diagnoses. Here, we demonstrate a novel method that uses the Raman signal as the signal-generating system of an ELISA and combines surface-enhanced Raman scattering (SERS) with silver nanoparticles aggregation for ultrasensitive analyte detection. The enzyme label of the ELISA controls the dissolution of Raman reporter-labeled silver nanoparticles through hydrogen peroxide and generates a strong Raman signal when the analyte is present. Using this assay, prostate-specific antigen (PSA) and the adrenal stimulant ractopamine (Rac) were detected in whole serum and urine at the ultralow concentrations of 10(-9) and 10(-6) ng/mL, respectively. The methodology proposed here could potentially be applied to other molecules detection as well as PSA and Rac.
Jiajie
J
Liang
Hongwu
H
Liu
Caihong
C
Huang
Cuize
C
Yao
Qiangqiang
Q
Fu
Xiuqing
X
Li
§Department of Laboratory Medicine, Guangdong No. 2 Provincial People's Hospital, Guangzhou 510317, People's Republic of China.
Donglin
D
Cao
Zhi
Z
Luo
Yong
Y
Tang
D001681:Biological Assay / Q000379:methods*; D015415:Biomarkers / Q000097:blood* / Q000652:urine*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D057230:Limit of Detection; D053758:Nanoparticles / Q000737:chemistry*; D010627:Phenethylamines / Q000097:blood; D017430:Prostate-Specific Antigen / Q000097:blood / Q000652:urine; D012680:Sensitivity and Specificity; D018030:Silver Compounds / Q000737:chemistry*; D013499:Surface Properties
D015415:Biomarkers; D010627:Phenethylamines; D018030:Silver Compounds; C060897:ractopamine; D017430:Prostate-Specific Antigen