Sensors for General Health Diagnostics Using Biomarkers in Bodily Fluids

The development of sensors for simple and low-cost everyday general health self-testing is receiving increasing attention. A key approach involves the detection of biomarkers levels in various bodily fluids: blood, urine, sweat, saliva [1]. Hormones produced by glands in the endocrine system and neurotransmitters produced by the nervous system control many bodily functions. The concentrations of these molecules in the body are an indication of its state, hence the use of the term biomarker. Excess concentrations of biomarkers, such as cortisol, serotonin, epinephrine, dopamine, are released by the body in response to a variety of conditions - emotional state (euphoria, stress), disease, etc. The development of simple, low-cost modalities for point-of-use (PoU) measurements of biomarkers levels in various bodily fluids (blood, urine, sweat, saliva) as opposed to conventional hospital or lab settings is receiving increasing attention. First, a review is presented of the basic properties of primary stress-related biomarkers: origin in the body (i.e. if they are produced as hormones, neurotransmitters or both), chemical composition, molecular weight (small or medium size molecules and polymers, ranging from ~ 100Da to ~ 100kDa), hydro- or lipo-philic nature [1].