Poster V20 - Microfluidic Sensor for Point-of-care Acetaminophen Toxicity Detection

Introduction: Acetaminophen toxicity in children poses a significant public health issue due to its potentially severe consequences. Often arising from accidental overdoses or dosage misjudgment, acetaminophen toxicity can lead to acute liver failure, a life-threatening condition. In fact, acetaminophen overdose is the leading cause of acute liver failure in the United States. Therefore, monitoring acetaminophen dosage is crucial to prevent overdoses and enable timely intervention. Blood sampling, an invasive procedure, is particularly challenging in children. Since salivary concentrations of acetaminophen closely correlate with plasma levels, measuring it in saliva is both valuable and non-invasive.

We introduce a microfluidic sensor for saliva collection and a laser-induced graphene (LIG) electrode to monitor salivary levels of acetaminophen at the point of care.

Materials and

Methods: Electrochemical techniques are analytical methods that typically involve the transfer of electrons between electrodes and chemical species in a solution. In Square Wave Voltammetry (SWV), a voltage is applied to the working electrode, and the resulting current produced by a redox reaction is measured. The capacitive/background current is eliminated by incrementally increasing the voltage through consecutive pulses, ultimately lowering the detection limit.

Laser-induced graphene (LIG) is a 3D porous carbon material formed using a laser source to pattern and convert a polymer into graphene. The fabrication of LIG electrodes is cost-effective and scalable, demonstrating favorable qualities for electrochemical sensor applications.

The microfluidic device is fabricated using polydimethylsiloxane (PDMS) by 3D printing a master mold using the MiiCraft Ultra 50 3D printer.

Results, Conclusions, and Discussions: Scaling up the fabrication process of LIG electrodes allows for a cost-effective production method. Examination of these electrodes shows the formation of a graphene layer on the PI film. Optimizing the laser machine parameters has resulted in electrodes with consistent reproducibility and improved electrochemical performance. The sensor can collect over 100 µL of saliva within 30 seconds, sufficient for conducting electrochemical measurements.

We have created a low-cost LIG-based microfluidic device designed to monitor acetaminophen levels in saliva, integrated with a portable potentiostat.

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