Microfabricated Reference Electrodes and their Biosensing Applications

Over the past two decades, there has been an increasing trend towards miniaturization of both biological and chemical sensors and their integration with miniaturized sample pre-processing and analysis systems. These miniaturized lab-on-chip devices have several functional advantages including low cost, their ability to analyze smaller samples, faster analysis time, suitability for automation, and increased reliability and repeatability. Electrical based sensing methods that transduce biological or chemical signals into the electrical domain are a dominant part of the lab-on-chip devices. A vital part of any electrochemical sensing system is the reference electrode, which is a probe that is capable of measuring the potential on the solution side of an electrochemical interface. Research on miniaturization of this crucial component and analysis of the parameters that affect its performance, stability and lifetime, is sparse. In this paper, we present the basic electrochemistry and thermodynamics of these reference electrodes and illustrate the uses of reference electrodes in electrochemical and biological measurements. Different electrochemical systems that are used as reference electrodes will be presented, and an overview of some contemporary advances in electrode miniaturization and their performance will be provided

Infertile Women in Developing Countries at Potentially High Risk of HIV Transmission

One hundred infertile women and 200 proven fertile women were recruited in Montepuez District, northern Mozambique, in order to elucidate the risk of syphilis and HIV seropositivity. TPHA seropositivity occurred in 55.0 per cent of infertile and 18.5 per cent of fertile women (OR 4.7; 95% CI 3.0-7.4). Among women with 2 lifetime spouses, 64.6 per cent of infertile women were TPHA seropositive, compared to 22.3 per cent of fertile women (OR 7.1; 95% CI 3.6-14.1). Three women (all infertile had HIV-1 antibodies and one, fertile, had HIV-2 antibodies. It concluded that infertile women constitute a group at potentially high risk of HIV infection once this infection is introduced into the community. (Afr J Reprod Health 1999; 3 (1): 98 - 102) Key Words: Infertility, syphilis, HIV infectio