Supplementary Material
Multiplexed Biomolecular Detection based on single
nanoparticles immobilized on pneumatically controlled
Microfluidic Chip
Bo Wu, Li-Chan Chen, Youju Huang, Zhang Yiming, Yuejun Kang, and Dong-Hwan
Kim*
School of Chemical and Biomedical Engineering, Nanyang Technological University,
637457, Singapore
Pneumatic system
A pneumatic system was experimentally designed to infuse the microfluidic chip with
reagents by controlling the integrated valves. As illustrated in Fig. S1(a), a pump was
used as a high pressure source to compress the air passing into the filter (Festo, USA) for
dust removal and desiccation. Down the line, a low-pressure regulator (0~10 bar outlet
range, Festo) protected the downstream of the system and stabilized the pressure
primarily. The compressed air was stored in a cylinder tanker (volume: 0.25 L, Festo) for
further pressure stabilization. Using a quadruple distributor (QSQ-6-4, Festo), four
control channels were branched off from the main channel. Each consisted of two air
flow valves (GRO-QS-4, Festo) and a gauge (MAP-40-1-1/8-EN, Festo) connected in
series. The pressure used to control the liquid flow rate was monitored by the gauge that
was controlled by the two air flow valves. As illustrated in Fig. S1(b), the valves were
operated at 2 bar and the reagent stored in the 1-mL tube was infused into the
microfluidic chip at 0.5 bar.
Fig. S1 (a) Schematic of the pneumatic system. (b) Schematic of the fluid reservoir.
Figures
Fig. S2 SEM image of gold nanorods. The gold nanorods were synthesized in length of
76.7±5.5 nm in width of 25.6±2.5 nm.
Fig. S3 UV-VIS absorption spectrum of gold nanorod suspension.
Fig. S4 Thickness of cured PDMS layers in function of spin-coating speed in range from
600 rpm to 900 rpm. The spin-coating time was 5 min. The PDMS prepolymer was
prepared by mixing PDMS base and its curing reagent in ratio of 20:1.
Fig. S5 Thickness of cured PDMS layers in function of spin-coating speed in range from
40 rpm to 150 rpm. The spin-coating time was 5 min. The PDMS prepolymer was
prepared by mixing PDMS base and its curing reagent in ratio of 5:1.