Point-of-Care Device with Plasmonic Gold Nanoarray Sensing Chip for Biomarker Detections
Point-of-care devices are highly desired not only in developing countries, but also in developed countries for the medical detection for remote/rural areas and home use. Compared with conventional bulky immunosystem widely used in central laboratories and
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Xiaodong Zhou, Ten It Wong, Ling Ling Sun, and Jie Deng
14.1 Introduction LSPR is generated on metal nanostructures upon the illumination of light whose energy can be absorbed by the nanostructures and cause collective electron charge oscillations on its surface. LSPR traps the light on the metal nanostructures surface within tens of nanometers, where the light is strongly enhanced by tens to hundreds of times. LSPR is particularly beneficial for chemical or biological detections. Because the sizes of the chemical or biological molecules are usually in a few nanometer range, they will be attached to the metal nanostructure surface roughly within the coverage of the strong LSPR field, thus the LSPR signal variation is relatively specific to the molecule attachment, i.e., the molecules not bound to the metal nanostructure will not much affect the detection signal, thus raw samples could possibly be tested without wash or purifications (Anker et al. 2008; Lee and El-Sayed 2006; Sherry et al. 2005). There are two methods to use LSPR for biosensors. One is to detect the shift of the LSPR absorption due to the refractive index change upon molecule binding. This is a direct assay that requires less time and cost; however, for some applications, the sensitivity might not be enough. The other is to utilize the LSPR to excite the fluorescent labels in a sandwich assay, because the labeled sandwich assay is intrinsically more sensitive than direct assay, and LSPR field is 10–100 times stronger than the incident light, the LSPR amplifies the fluorescent labels and
X. Zhou (*) • T.I. Wong • J. Deng Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, #08-03, Innovis, Singapore 138634, Singapore e-mail: [email protected] L.L. Sun Temasek Microelectronics Centre, School of Engineering, Temasek Polytechnic, 21 Tampines Avenue 1, Singapore 529757, Singapore © Springer Nature Singapore Pte Ltd. 2017 P. Chandra et al. (eds.), Next Generation Point-of-care Biomedical Sensors Technologies for Cancer Diagnosis, DOI 10.1007/978-981-10-4726-8_14
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324 Assay decision
X. Zhou et al. Nanostructure simulation
Nanochip fabrication
Biofunction -alization
Microfluidic chip
Point -of-care development
Fig. 14.1 The development process of a LSPR-based point-of-care device
achieves quite high sensitivity. Since both methods can be applied on the development of a point-of-care device, the selection of detection methods is based on sensitivity requirements for different applications. The development of a LSPR-based point-of-care device has a flow chart illustrated in Fig. 14.1. The first step is to identify the nanoparticles and the related bioassay that can meet the requirement of the specific application. After which, some plasmonic simulation is required to identify the plasmonic peak and the LSPR field distribution, thus the suitable light source can be found and the size, shape, and inter-distance of the nanoparticles can be optimized. LSPR can
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