Candidate: Fatemeh Keyvani
Date: April 8, 2026
Time: 12:30 PM
Location: Online
Supervisor: Mahla Poudineh
All are welcome!
Abstract:
Conventional disease diagnosis and health monitoring rely on centralized laboratory testing that requires invasive biofluid collection, complex processing, and specialized equipment. These methods are costly, time-consuming, and provide only intermittent data, limiting their utility for timely decision-making. This thesis addresses these challenges by developing advanced biosensing platforms that combine minimally invasive sampling with different detection modalities to enable point-of-care (POC) diagnostics and continuous monitoring. The overarching vision is to enable on-site biomarker quantification and continuous monitoring of disease-relevant indicators. The first platform focuses on POC screening for cervical cancer (CC), a disease that disproportionately affects women in low- and middle-income countries due to limited access to screening. We developed an Integrated Microfluidic Electrochemical Assay for Cervical Cancer (IMEAC), a low-cost and user-friendly system that combines a force-free plasma separation module with a graphene oxide-based electrochemical biosensor. The plasma separator isolates high-purity plasma directly from whole blood, while the biosensor employs sequence-specific probes to detect circulating tumor nucleic acid. The second platform expands the concept of decentralized diagnostics toward general clinical biomarker monitoring. We designed a hydrogel microneedle (HMN)–based assay capable of sampling interstitial fluid (ISF) in a minimally invasive manner. The extracted ISF is analyzed using a graphene oxide–nucleic acid (GO.NA) fluorescence biosensor, enabling real-time detection of clinically relevant biomarkers. This system was complemented with a portable fluorescence detector, yielding a complete and user-friendly POC solution.
Building upon these foundations, the third platform centers on therapeutic drug monitoring (TDM), a clinical necessity for optimizing treatment efficacy. We developed a hybrid microneedle–flexible electrode biosensor (HMN-Flex) capable of real-time monitoring of two widely used antibiotics: vancomycin and gentamicin. The HMN array extracts dermal ISF and delivers it to an electrode, where target antibiotic concentrations are quantified electrochemically. The HMN-Flex system was validated in-vivo using rat models, with pharmacokinetic profiles showing strong concordance with conventional blood-based assays. The fourth platform translates the principles of minimally invasive, continuous biosensing into the neurocritical care environment. Patients with external ventricular drains (EVDs) require close monitoring of cerebrospinal fluid (CSF) to detect complications such as infection and drain malfunction. We developed NeuroSense, a multiplexed sensing platform that integrates seamlessly with standard EVD systems to provide continuous, real-time monitoring of CSF. NeuroSense provides measurements of CSF glucose, lactate, pH, and flow rate, thus reporting about potential infection and EVD malfunction. Taken together, the works presented in this thesis demonstrate how integrating novel sampling strategies, nanomaterial-enabled biosensors, and system-level design with interdisciplinary advances in microfluidics, microneedles, and electrochemical and optical sensing can overcome intrinsic limitations of laboratory-based diagnostics. These platforms establish a technological foundation for next-generation healthcare systems that prioritize accessibility, timeliness, and personalization, with the potential to improve patient outcomes in high-resource clinical settings and expand access to quality care in underserved regions worldwide.