Bead-Based Bio-Signal Enhancement with an Optoelectrokinetic Technique

摘要

In the early stage of diseases biomarkers may be hard to detect due to low concentration As a result improving the bio-signal is an important issue A considerable number of research studies have proven particles to be useful carriers in many bead-based bioassays However most of them require complex fabrication to achieve efficient collection of beads To solve this problem this thesis presents a simple optoelectrokinetic method for bead-based sensing carrier concentration Since the optoelectrokinetic method combines the laser and AC electric field laser intensity voltage and frequency were investigated for the optoelectrokinetic manipulation The result shows that concentration efficiency increases as the light intensity or voltage is elevated Our study shows that carefully tuning of frequency path of irradiation and voltage several manipulation capabilities such as particle concentration translation single particle trapping sorting and patterning can be achieve Accordingly this optoelectrokinetic method can be developed to a versatile examination platform For assessment of low-dose sample detection streptavidin functionalized particles (6 μm) and FITC tagged biotin were used The biotin-FITC represents a biomarker in a biological fluid while the streptavidin functionalized particles represent a platform of an immunoassay The results showed that trace amounts of biotin (3 87 nM) signals were detected by confined the biotins in a micro scale domain As compared with the conventional instrument ELISA Reader the signal was improved by at least two orders of magnitude To assess the effect of signal enhancement by the optoelectrokinetic method the mixture of sensing carrier and analyte is concentrated by optoelectrokinetic method The results show that bio-signals make noticeable enhancement over time These results indicated that both bead-based bioassay and optoelectrokinetic method can effectively improve the bio-signal The final goal of this thesis is to detect the diabetic retinopathy Diabetic retinopathy is the most common diabetic eye disease and a leading cause of blindness in many countries To achieve simple examination FRET-based immunoassay was used to detect the LCN1 which is known as one of the diabetic retinopathy biomarker This sensing system uses dye (acceptor) labeled antibody linked to polystyrene bead to capture antigen The antigen binds to a quantum dot (donor) functionalized antibody thus forming a FRET donor–acceptor ensemble Subsequently FRET-based immunecomplexes were concentrated by optoelectrokinetic method The result reveals that the signal improves noticeably within 40 seconds and the FRET-induced dye s ignal intensity is higher with the target protein than in its absence This result indicates that biomarker LCN1 can be detected by FRET-based immunoassay In the future the others biomarker of disease can be detected with the different identify antibody in the same fashion

獎項日期	2014 8月 28
原文	English
監督員	Han-Sheng Chuang (Supervisor)