Publication

Low-cost photolithographic fabrication of nanowires and microfilters for advanced bioassay devices

Doan, Nhi
; 
Qiang, Liangliang
; 
Li, Zhe
; 
Vaddiraju, Santhisagar
; 
Bishop, Gregory
; 
Rusling, James
; 
Papadimitrakopoulos, Fotios
Repository DOI
Publication Date
2015-03-12
Keywords
nanowire, nanogaps, microelectrode arrays, sensor, immunoassay, microfluidic, photolithography, isotropic etching, cancer biomarker proteins, microfluidic chips, alpha-fetoprotein, magnetic beads, scale features, electron-beam, arrays, immunoassay, lithography, electrodeposition
Type
Article
Downloads
Show all metadata
Citation
Doan, Nhi; Qiang, Liangliang; Li, Zhe; Vaddiraju, Santhisagar; Bishop, Gregory; Rusling, James; Papadimitrakopoulos, Fotios (2015). Low-cost photolithographic fabrication of nanowires and microfilters for advanced bioassay devices. Sensors 15 (3), 6091-6104
Abstract
Integrated microfluidic devices with nanosized array electrodes and microfiltration capabilities can greatly increase sensitivity and enhance automation in immunoassay devices. In this contribution, we utilize the edge-patterning method of thin aluminum (Al) films in order to form nano- to micron-sized gaps. Evaporation of high work-function metals (i.e., Au, Ag, etc.) on these gaps, followed by Al lift-off, enables the formation of electrical uniform nanowires from low-cost, plastic-based, photomasks. By replacing Al with chromium (Cr), the formation of high resolution, custom-made photomasks that are ideal for low-cost fabrication of a plurality of array devices were realized. To demonstrate the feasibility of such Cr photomasks, SU-8 micro-pillar masters were formed and replicated into PDMS to produce micron-sized filters with 3-4 mu m gaps and an aspect ratio of 3. These microfilters were capable of retaining 6 mu m beads within a localized site, while allowing solvent flow. The combination of nanowire arrays and micro-pillar filtration opens new perspectives for rapid R&D screening of various microfluidic-based immunoassay geometries, where analyte pre-concentration and highly sensitive, electrochemical detection can be readily co-localized.
Funder
Publisher
MDPI AG
Publisher DOI
10.3390/s150306091
Rights
Attribution-NonCommercial-NoDerivs 3.0 Ireland
cbn
Collections
Externally hosted open access publications with University of Galway authors (2)