奈米工程與微系統研究所　書報討論

Seminar of Inst. NanoEngineering and MicroSystems

Saving Lives with Micro/Nano-Beads

Abstract

Early diagnosis is an ideal measure for effective treatments. However, dilute analytes form a high barrier in detection. To tackle the problem, micro/nano-beads are commonly functionalized with ligands to capture target molecules. As a result, they can be employed as smart probes to alarm users the occurrences of diseases or pathogens in the early stage. In this presentation, two self-developed techniques in our laboratory involving with functional micro/nano-beads will be introduced to show how they were used in some specific biomedical applications. In the first case, an optoelectrokinetic technique, termed rapid electrokinetic patterning (REP), was developed to manipulate micro/nano-beads. A comprehensive repertoire of manipulation, including size sorting, translation, concentration, and single particle trapping were all explored. By properly concentrating dye-labelled beads, weak biosignal can be enhanced. Two biomarkers in tears, LCN1 and TNF-α, for diabetic retinopathy were successfully detected in a concentration level down to 100 pg/mL. In another case, Brownian motion, a thermal random noise, was employed here to harness functional micro/nano-beads. According to the Einstein relation, particle diameter is inversely proportional to diffusivity. Therefore, the concentration variation of any target in a sample medium can be simply estimated from its diffusivity change. Micro/nano-beads were coated with specific antibodies to induce immunoreactions with their corresponding targets. For microbial tests, bacteria, P. aeruginosa, S. aureus, and E. coli were respectively studied for their diffusivity responses. It was found that the diffusivity changes were in relation to the numbers of the bacteria. A limit of detection (LOD) as low as one bacterium per particle was achieved. The result was further used to improve the anti-microbial susceptibility testing (AST). The turnaround time for each AST measurement was then significantly reduced from days to hours (~2 h). Notably, the same platform but conjugated with additional gold nanoparticles was further attempted to challenge the detection limit of a trace amount of food toxin, botulinum. The LOD for such a configuration eventually achieved 10 pg/mL. Overall, the diffusion-enabled technique requires neither complicated fabrication nor sophisticated instruments. In conclusion, both proposed techniques provide great insight to saving lives with micro/nano-beads by enabling early diagnosis. An attempt to build a prototype to bring the diffusion-enabled technique from theory to practice is also under way.

15:30-17:20 on Mar. 26(Mon), 2018 at Room 108 of Eng. Building I

Host：Prof. J.Andrew Yeh jayeh@mx.nthu.edu.tw Ext:42912 ,TA：Eva Huang crazy8826@gmail.com