A microfluidic lab-on-a-chip (LOC) device for in-situ synthesis of gold nano-particles
was developed. The long term goal is to develop a portable hand-held diagnostic
platform for monitoring water quality (e.g., detecting metal ion pollutants).
The LOC consists of micro-chambers 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 reagents/ samples to flow into and out of
the reaction chamber. Passive flow actuation is obtained by capillary driven flow
(wicking) and dissolvable microstructures called ‘salt pillars’. The LOC does not require
any external power source for actuation and the passive microvalves enable flow
actuation at predefined intervals. The LOC and the dissolvable microstructures are
fabricated using a combination of photolithography and soft lithography techniques.
Experiments were conducted to demonstrate the variation in the valve actuation time
with respect to valve position and geometric parameters. Subsequently, analytical models were developed using one dimensional linear diffusion theory. The analytical
models were in good agreement with the experimental data. The microvalves were
developed using various salts: polyethylene glycol, sodium chloride and sodium acetate.
Synthesized in-situ in our experiments, gold nano-particles exhibit specific colorimetric
and optical properties due to the surface plasmon resonance effect. These stabilized
mono-disperse gold nano-particles can be coated with bio-molecular recognition motifs
on their surfaces. A colorimetric peptide assay was thus developed using the intrinsic
property of noble metal nano-particles. The LOC device was further developed on a
paper microfluidics platform. This platform was tested successfully for synthesis of gold
nano-particles using a peptide assay and using passive salt-bridge microvalves.
This study proves the feasibility of a LOC device that utilizes peptide assay for
synthesis of gold nano-particles in-situ. It could be highly significant in a simple
portable water quality monitoring platform.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-3189 |
| Date | 15 May 2009 |
| Creators | Datta, Sayak |
| Contributors | Banerjee, Debjyoti |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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