Synthesis of Nano-Particles using a Lab-On-Chip (LOC) Device for Water Quality Monitoring Applications
Objective: Our aim is to investigate the synthesis of gold nano-particles using a lab-on-chip (LOC) platform using peptide assays. The purpose of this research is to develop a portable hand held diagnostics platform for monitoring water quality and detecting metal pollutants.
Problem Definition: Detection of metal ions form an integral part of water quality monitoring and health management. Traces of arsenic and similar toxic elements are major pollutants in various sources of water which need to be detected. Gold nano-particles are synthesized in-situ in our experiments using peptide assays. The gold nano-particles exhibit various optical properties due to Surface Plasmon Resonance (SPR). These stabilized mono-disperse gold nano-particles are coated with bio-molecular recognition motifs on their surfaces for reacting with specific metal ions. The stabilization and functionalization with bio-molecular recognition motif provides flexibility for various applications. For example, the gold nano-particles synthesized by this process are tested for their ability to be recognized by a surface coated with antibodies.
General Procedure: The LOC consists of microwells (or reservoirs) housing different reagents and samples that feed to a common reaction chamber. The reaction products are delivered to several waste chambers in a pre-defined sequence to enable subsequent reagents/ samples to flow into the reaction chamber. Passive flow actuation is obtained by capillary driven flow (wicking), and dissolvable micro-structures that act as passive microvalves. The advantage of these microvalves is that they actuate at predefined intervals and do not require any external power source for actuation. The microfluidic chip (LOC) and the dissolvable microstructures are fabricated using the soft lithography techniques. The passive valves are incorporated into the micro-fluidics platform by novel micro-fabrication and bonding techniques.
Conclusion and Future Direction: We have successfully demonstrated the synthesis of the gold nano-particles using these Lap-On-Chip platforms in our labortory. We are developing a two-layer microfluidic chip. Also, we are characterizing the passive microvalves for the actuation time as a function of geometric parameters and property values.