Direct detection and identification of low concentrated biological molecules selectively and sensitively without any labeling is necessary to obtain molecular finger printing information in short time, decrease significantly the mortality rate and reduce the cost of treating the sample. However, there is no existing technology to detect a variety size and shape of biological molecule from the biomedical sample in short time effectively. Here, we have developed a sensing platform of digital microfluidics to achieve label free detection of biological molecule. We reports that self-assembled plasmonic nanoparticles on the surface of droplets at hydrophilic / hydrophobic interface termed here as plasmonic droplet. The self- assembly mechanism is hydrophobic interaction between cetyltrimetyl ammonium bromide modified plasmonic nanoparticle and oil at interface junction. The dynamics of the plasmonic nanoparticle assembly is observed using dark field microscopy. This plasmonic droplet is generated in microfludic device with high throughput in size variation from 40 ~ 120 µm in 50 µm channel dimension. We can simply change optical property of the plasmonic droplet by altering the species of plasmonic nanoparticle. Until now, gram negative and positive bacteria could be distinguished in this plasmonic droplet and now cytokine detection is targeting. Potentially, this plasmonic droplet enables a sensing platform of digital microfluidics for artificial cell, immune-system analysis and cytokine detection.
Project end date: 01/18/12