Low-Cost Photolithographic Fabrication of Nanowires and Microfilters for Advanced Bioassay Devices

Sensors

Nhi M. Doan²  Liangliang Qiang²  Zhe Li²  Santhisagar Vaddiraju²  Gregory W. Bishop¹  James F. Rusling¹  Fotios Papadimitrakopoulos² 

[1] Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA; E-Mails:;Nanomaterials Optoelectronics Laboratory, Polymer Program, University of Connecticut, Storrs, CT 06269, USA; E-Mails:

关键词: nanowire;    nanogaps;    microelectrode arrays;    sensor;    immunoassay;    microfluidic;    photolithography;    isotropic etching;   

DOI  :  10.3390/s150306091

来源: mdpi

【 摘 要 】

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 µm gaps and an aspect ratio of 3. These microfilters were capable of retaining 6 µm 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.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.