Authors: Seyed Y. S. Lisar, Rouhollah Motafakkerazad, Mosharraf M. Hossain and Ismail M. M. Rahman

Screen printing technology provides a cheap and easy means to fabricate disposable electrochemical devices in bulk quantities which are used for rapid, low-cost, on-site, real-time and recurrent industrial, pharmaceutical or environmental analyses. Recent developments in micro-fabrication and nano-characterization made it possible to screen print reproducible feature on materials including plastics, ceramics and metals. The processed features forms screen-printed disposable biochip (SPDB) upon the application of suitable bio-chemical recognition receptors following appropriate methods. Adequacy of biological and non-biological materials is the key to successful biochip development. We can further improve recognition ability of SPDBs by adopting new screen printed electrode (SPE) configurations. This review covers screen-printing theory with special emphasis on the technical impacts of SPE architectures, surface treatments, operational stability and signal sensitivity. The application of SPE in different areas has also been summarized. The article aims to highlight the state-of-the-art of SPDB at the laboratory scale to enable us in envisaging the deployment of emerging SPDB technology on the commercial scale.

Rapid and definitive diagnosis is critical to the prevention of the spread of endemic human pathogenic viruses. Detection of variant specific genes by reverse transcription polymerase chain reaction (RT-PCR) has become a routine diagnostic test for accurate subtyping of RNA viruses, such as influenza. In this paper, we demonstrate the use of a continuous-flow polydimethylsiloxane (PDMS) microfluidic RT-PCR chip and disposable electrical printed (DEP) chips for rapid amplification and sensing of new influenza (AH1pdm) virus of swine-origin. The RT-PCR chip consisted of four zones: RT reaction zone, initial denaturation zone, thermal cycle zone for PCR (2-step PCR) and pressurizing-channel zone for preventing air-bubble formation. In order to measure electrochemical signals, methylene blue (MB), an electro-active DNA intercalator, was added to the RT-PCR mixture. The RT-PCR was completed within 15 min which was the total flow-through time from the inlet to the outlet, and the reduction signals from amplifications could be detected quickly on the DEP chip. The MB reduction current on the DEP chip with the amplicon significantly reduced compared to non-amplified controls. This microfluidic platform for rapid RT-PCR and the DEP chip for quick electrochemical sensing are suitable for integration, and have the potential to be a portable system for diagnostic tests.