Microfluidic Synthesis Of ZnO Nanorods For Fluorescence Biodetection

Biomarker is s kind of proteins associated with the structural and functional change of organs,tissues and cells.It played an important role in the diagnosis and therapy of diseases and the evaluations of drugs.In particular,it is significant to develop the detection devices with high specificity and sensitivity to perform rapid and accurate detection of biomarkers in early diagnosis and therapy.Fluorescence immunoassay has been widely used in the detection of various biomarkers,because of its good specificity,easy manipulation,high sensitivity and high signal-to-noise ratio.Recently,nanomaterials have been extensively utilized in the detection of biomarkers due to the excellent optical and electrical properties.At the meantime,integration of nanomaterials into multiplexed microfluidic device for the detection of biomarkers can improve the sensitivity and efficiency of detection,and provides a novel approach for the miniaturization,integration,and portability of medical detection.In this work,insitu synthesis of Zinc Oxide(ZnO)nanorods was carried out on microfluidic chip and used to detect C-reactive protein.The main content of this paper were summarized as follows:1.A simple multichannel chip was designed and prepared.ZnO nanorods of different diameters and lengths were hydrothermally synthesized in multichannel chips by changing the growth time(0.5 h,1 h,2 h)and flow rate(7.2 ?L/min,14.4 ?L/min,21.6 ?L/min,28.8 ?L/min,36.0 ?L/min).The results showed that the ZnO nanorods synthesized by localized heating held better homogeneity.FITC conjugated anti-bovine immunoglobulin G(FITC-IgG)was used to investigate the fluorescence enhancement of ZnO nanorods synthesized by global heating and localized heating at different flow rates.ZnO nanorods synthesized by localized heating showed better performance.ZnO nanorods prepared at the flow rate of 28.8 ?L/min for 1 h showed optimal detection performance.2.ZnO nanorods were prepared using optimized synthesis conditions and utilized to detect the cardiovascular disease marker CRP.Firstly,taking FITC-anti bovine IgG as a sample to test the response time.The continuous perfusion and perfusion followed by incubation were both used for detection.The results showed that the response time of the latter was shorter.The fluorescence intensity reached saturation after 12 min of perfusion followed by 6 min of incubation.The detection of CRP was performed by direct immunofluorescence assay and sandwich immunofluorescence assay,respectively.The results showed that the latter has higher sensitivity and lower detection limit,and achieving the detection limit(LOD)of 10 fg/mL.Finally,the investigation of interfering proteins including Myoglobin and BSA was performed at the same concentration of 1 ?g/mL.The results showed that slight decrease in fluorescence intensity was observed in the presence of interfering proteins.It further demonstrated that this integrated microfluidic chip can detect different concentrations of protein,improve detection efficiency and show good prospects in clinical trials and POC detection.