ABSTRACT
A peptide microarray-based fluorescence and resonance light scattering ( RLS ) two readout assay was developed for screening thrombin inhibitors in blood samples. In this assay, the biotinylated peptide microarray was used as the platform. The peptide C-terminal fragments carried biotin sites departed from the slide when the biotinylated peptides were digested by thrombin hydrolysis reaction. The hydrolysis progress was labeled by fluorescence and 30 nm peptide-stabilized gold nanoparticles through the biotin-avidin reaction. In the presence of thrombin inhibitors, the hydrolysis reactions were blocked, and the inhibition capability of inhibitors could be detected by the fluorescent and RLS signal changes. The order of the half maximal inhibitory concentration ( IC50 ) of thrombin inhibitors in pure thrombin solution and spiked human serum were argatrobanHAT-Ⅲ>trypsin inhibitor>E-64>AEBSF. The reversible or irreversible characters of argatroban and HAT-Ⅲ had been estimated in human plasma. Compared with the experimental data of fluorescent and RLS assay in blood sample, the RLS assay labeled by 30 nm gold nanoparticles are more suitable for the inhibitor detection in complicated blood sample.
ABSTRACT
Objective To quantitatively detect CA125 with self-designed synthetic gold nanoparticle probes by the colorimetric immunoassay and to initially investigate the feasibility of clinical application .Methods The capture antibody of detective CA125 was conjugated to the gold nanoparticle surface for preparing the gold nanoparticle probes .The gold nanoparticle aggregation was formed by the antigen-antibody immunoreaction .CA125 was quantitatively detected by the colorimetric immunoassay .Results The gold nanoparticle probes was successfully prepared ,which could detect the serum CA125 content rapidly and conveniently ,the de-tection results were coincident with the pathological diagnosis .The lowest limit of quantitation was 0 .5 U/mL ,which was far lower than that in ELISA .Conclusion This gold nanoparticle probes are simple to be prepared ,rapid and easy to operate with low cost , and have the important application value in clinical early detection of ovarian cancer marker CA 125 ,especially in the primary hospi-tals .