New Sensor Promises Rapid Detection

Photo: Lab-on-a-Chip Sensor

Researchers have created a sensor that provides fast feedback related to the presence and levels of heavy metals – specifically manganese – in humans. The key aspect of the project was the development of a low-cost, disposable lab-on-a-chip sensor that detects highly electronegative heavy metals more quickly than current technology generally available in health-care settings. It’s envisioned that the new sensor technology will be used in point-of-care devices that provide needed feedback on heavy-metal levels within about ten minutes.

Explained one of the researchers, Ian Papautsky, “The conventional methods for measuring manganese levels in blood currently requires about five milliliters of whole blood sent to a lab, with results back in 48 hours. For a clinician monitoring health effects by measuring these levels in a patient’s blood – where a small level of manganese is normal and necessary for metabolic functions – you want an answer much more quickly about exposure levels, especially in a rural, high-risk area where access to a certified metals lab is limited. Our sensor will only require about two droplets of blood serum and will provide results in about ten minutes. It’s portable and usable anywhere.”

The new sensor uses a technology called anodic stripping voltammetry that incorporates three electrodes: a working electrode, a reference electrode and an auxiliary electrode.

A critical challenge for such sensors is the detection of electronegative metals like manganese. Detection is difficult because hydrolysis, the splitting of a molecule into two parts by the addition of a water molecule, at the auxiliary electrode severely limits a sensor’s ability to detect an electronegative metal. To resolve this challenge, the UC team developed a thin-film bismuth working electrode vs. the conventional mercury or carbon electrode. The favorable performance of the bismuth working electrode combined with its environmentally friendly nature means the new sensor will be especially attractive in settings where a disposable lab-on-a-chip is wanted.

In addition, the team also optimized the sensor layout and working-electrode surface to further reduce the effects of hydrolysis and to boost the reliability and sensitivity in detecting heavy metals. The new sensor layout better allowed for its functioning, which consists of taking of a blood serum sample, stripping out the heavy metal and then measuring that heavy metal.

The end result is the first lab-on-a-chip able to consistently pinpoint levels of highly electronegative manganese in humans. The new sensor also exhibits high reliability over multiple days of use, with hours of continuous operation. With further developments, the chip may even be converted into a self-check mechanism, such as with glucose screening for diabetics.; Source: University of Cincinnati