Schizophrenia is a challenging and complex disorder with 30–50% of patients not responding to first line antipsychotic treatment. Clozapine is the only antipsychotic approved by the FDA for treatment-resistant schizophrenia and is the most effective antipsychotic medication currently available. Yet, clozapine remains underutilized because of the requirements for frequent invasive and burdensome monitoring to 1) titrate doses to achieve effective blood levels, as well as 2) monitor white blood cells on a weekly basis for the first six months due to risk of agranulocytosis, a rare but potentially fatal side effect of clozapine. These blood draws, and the time lag in receiving reports from central labs, can add several more visits to the caregivers' treatment plan, which may not be feasible for the patient nor the treatment team. This contributes to a very low prescription rate for clozapine, making it one of the most underutilized evidence-based treatments in the field of mental health.

The objective of this work is to progress toward a point-of-care approach to monitor both white blood cells and clozapine within a clinical setting. This would significantly lower the burden associated with clozapine treatment by allowing both tests to be performed rapidly during a single doctor's office visit or at the pharmacy. Specifically, I have developed and studied novel clozapine detection schemes based on electrochemical signal amplification in chitosan-based films. Moreover, I have investigated impedance cytometry coupled with hydrodynamic focusing and osmotic lysis to provide label- and reagent-free differential white blood cell counting capabilities. Finally, I have integrated the components in a microsystem capable of concurrent sensing of both biomarkers in whole blood samples. This proof-of-concept device lays the foundation for a fully integrated and automated lab-on-a-chip for point-of-care or even at-home testing to ensure treatment adherence, efficacy, and safety. This will allow for broader use of clozapine by increasing convenience to patients as well as medical professionals, thus improving the lives of people affected by schizophrenia through personalized medicine.