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A major goal of environmental agencies today is to conduct point-of-collection monitoring of excess inorganic phosphate (Pi) in environmental water samples for tracking aquatic “dead zones” caused by algae blooms. However, there are no existing commercial devices which have been miniaturized and are suitable for the point-of-need-testing (“PONT”) that is required to fully map a large region, such as the Florida Everglades. To solve this challenge, a reflection-mode fluorescence-sensing apparatus was developed, leveraging an environmentally sensitive fluorophore (MDCC) bound to a bacterial phosphate-binding protein to generate a fluorescent optical signal proportional to the concentration of (Pi) present. The combined end-to-end integrated sensor system had a response time of only 4 s, with minimal effects of common interfering agents and a linear range spanning from 1.1 to 64 ppb. To support ease-of-use during PONT, the platform incorporated disposable wax-printed paper strip sample pads and a smartphone camera detection system. Since the EPA threshold is currently 30 ppb to prevent eutrophication, this system serves as a rapid test of whether a region is compliant.

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Non-glucose biomarker-DNA oxidative damage biomarker 8-hydroxy-2′-deoxyguanosine (8-OHdG) has been successfully detected using a smartphone-enabled glucose meter. Through a series of immune reactions and enzymatic reactions on a solid lateral flow platform, 8-OHdG concentration has been converted to a relative amount of glucose, and therefore can be detected by conventional glucose meter directly. The device was able to detect 8-OHdG concentrations in phosphate buffer saline as low as 1.73 ng mL −1 with a dynamic range of 1–200 ng mL −1 . Considering the inherent advantages of the personal glucose meter, the demonstration of this device, therefore, should provide new opportunities for the monitoring of a wide range of biomarkers and various target analytes in connection with different molecular recognition events.

The phrase "oxidative-stress induced DNA damage" is commonly used in both the scientific literature and common media outlets, and is frequently linked to detrimental elements of aging as well as the onset of illnesses. Due to the growing focus on this topic, a clear need has emerged to develop a quantitative, low-cost methodology to allow for periodic monitoring of oxidative-stress induced DNA damage within individuals. Recent literature examining the link between oxidative stress and the onset of various cancers has made monitoring an even more pressing need. The mechanism of oxidative-stress induced DNA damage originates in chronic inflammation, which in turn activates various transcription factors and diseases that influence the onset of tumor development, chemoresistance, radioresistance, and other harmful cellular processes. While current technologies that aim to provide quantitative metrics require extremely expensive equipment and significant technical expertise, our laboratory has designed a low-cost methodology utilizing a combination of carbon nanotubes, paper electrodes, and immunochromatographic strips.

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