Gold nanoparticles amplified ultrasensitive quantification of human urinary protein by capillary electrophoresis with on-line inductively coupled plasma mass spectroscopic detection.
Quantitative analysis of proteins play pivotal roles in basic discovery research and clinical applications, and the analytical challenge is to provide sufficient sensitivity to determine the proteins at endogenous levels. Here, we report a strategy for ultrasensitive quantification of human urinary protein by capillary electrophoresis with on-line inductively coupled plasma mass spectroscopic detection (CE-ICPMS) in conjunction with gold nanoparticles (AuNPs) amplification. The albumin in the sample solution was incubated with excess AuNPs to form the AuNP-albumin adduct. The excess AuNPs and the AuNP-albumin adduct were then effectively separated by CE for on-line ICPMS detection. As a result of AuNPs-tagging, more than 2000 gold atoms on average were attached to each albumin molecule to successfully achieve a significant amplification of ICPMS signal with extremely low limit of detection (0.5 pM for 280 nL of sample injection, corresponding to 0.1 amol) and a wide linear response over 4 orders of magnitude. The relative standard deviations of the migration time, peak area, and peak height for seven replicate injections of a mixture of 0.4 pM AuNPs and 9.0 pM albumin ranged from 1.8% to 4.4%. The developed method was successfully applied for detecting albumin in human urine samples with quantitative recoveries in the range of 93.0-99.7%. The methodology demonstrated here has potential for simultaneous determination of low-abundance multiple biomarkers of interest via multiple nanomaterials tags because of high-resolution CE separation and ultrasensitive ICPMS detection.
Liu
Jing-Min
JM
Research Center for Analytical Sciences, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin 300071, China.
Li
Yan
Y
Jiang
Yan
Y
Yan
Xiu-Ping
XP
D000419:Albuminuria / Q000652:urine*; D019075:Electrophoresis, Capillary / Q000379:methods*; D006046:Gold / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D013058:Mass Spectrometry / Q000379:methods*; D053768:Metal Nanoparticles / Q000737:chemistry; D053761:Nanocomposites / Q000737:chemistry; D010316:Particle Size; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D006046:Gold