Walid AlChamaa

High throughput, high sensitivity, and scalability point-of-care biosensors have the potential to significantly improve diagnosis and disease monitoring. Organic electrochemical transistors (OECTs) are a powerful platform for point-of-care biosensing given their sensitivity and performance. Unfortunately, this is seldom achieved with novel and cost-effective fabrication methods. In this work, we built high-performance OECTs using state-of-the-art inkjet printing technology a, scalable, highly reproducible, and low-cost fabrication process. The design utilizes unique high conductivity PEDOT: PSS formulations driving higher ion-to-electron conversion, and volumetric capacitance reaching a value of 18.524 F cm ⁻³ . The design included a high ratio of channel cross-sectional area to length reaching a maximum corresponding transconductance (g _m ) value of 15.2 mS, an order of magnitude improvement on published work. The design was also tested with Bovine Serum Albumin (BSA) protein and showed a limit of detection on the order of 1 pM of BSA. This work shows the potential of inkjet printing for fabricating low-cost, high-performance OECT-based point-of-care biosensors.

Neural interfaces are the part of the neural prosthesis that is in contact with the target tissue. The mechanical, chemical, and electrical properties of these interfaces can be a major determinant of the life of the implant and the neural tis-sue for chronic and even acute integrations. In this work, we developed a fully inkjet-printed, flexible neural interface on a bioresorbable backbone capable of recording high-fidelity neural activity. We utilized room temperature fabrication processes that overcome the limitations of semiconductor fabrication techniques for processing low-melting point polymers while maintaining high-spatial and single-cell recording resolution. The ~8 µm-thick devices in this study were fabricated onto two flexible polymers: (a) polyimide (PI), a biocompatible polymer commonly used for neural interfaces, and (b) polycaprolac-tone (PCL), a bioresorbable polyester with outstanding mechanical properties. Electrodes for neural recording were built at 30, 50, 75, 100 µm diameter using AgNPs/(3,4- ethylenedioxytiophene)-poly(styrenesulfonate) (AgNPs/PEDOT:PSS), which through our process achieved the lowest impedance reported in literature reaching ∼200 Ω at 1 kHz for a 50 µm elec-trode diameter. We further enhanced the electrochemical performance of AgNPs/PEDOT:PSS by an order of magnitude by incorporating exfoliated graphene into the electrodes. The biocompatibility of the fabricated devices and their ability to rec-ord single-unit activity were confirmed by in-vitro tests on both rat PC12 cells and isolated neural rat retina, respectively.

The potential clinical utility of circulating tumor cells (CTCs) in the diagnosis and management of cancer has drawn a lot of attention in the past 10 years. CTCs disseminate from tumors into the bloodstream and are believed to carry vital information about tumor onset, progression, and metastasis. In addition, CTCs reflect different biological aspects of the primary tumor they originate from, mainly in their genetic and protein expression. Moreover, emerging evidence indicates that CTC liquid biopsies can be extended beyond prognostication to pharmacodynamic and predictive biomarkers in cancer patient management. A key challenge in harnessing the clinical potential and utility of CTCs is enumerating and isolating these rare heterogeneous cells from a blood sample while allowing downstream CTC analysis. That being said, there have been serious doubts regarding the potential value of CTCs as clinical biomarkers for cancer due to the low number of promising outcomes in the published results. This review aims to present an overview of the current preclinical CTC detection technologies and the advantages and limitations of each sensing platform, while surveying and analyzing the published evidence of the clinical utility of CTCs.

Car accidents are becoming a growing concern to people with a history of chronic heart diseases. While some solutions have been proposed to detect the onset of heart attacks in automotive drivers, the existing applications are not comprehensive to provide the full accuracy of the detection process and encumber the driver to perform difficult tasks during a heart attack. Using pervasive technology, it is possible to collect in real-time the major symptoms at the onset of a heart attack. The heart rate, body temperature, and skin resistance can be quantitatively measured non-invasively; while, the qualitative symptoms of dizziness, nausea, fatigue, chest pain, and numbness in the left hand can be confirmed by the driver using an interactive system that non-intrusively asks the driver about his/her current physical state. In this sense, this paper describes the design, development, and validation of an instrumented steering wheel that guides an individual who is experiencing a heart attack through a safe process that may save his/her life and reduces the risks of accidents with bystanders or drivers in the vicinity. Data from various inputs are analyzed in real-time using a custom-developed smart algorithm implemented on an Arduino single-board microcontroller. If the algorithm determines that the user is at risk of a heart attack, the device performs the following actions automatically within 30 seconds: i) dispatches the current location of the driver to the paramedics with an SMS; ii) warns other drivers in the vicinity that there is a medical emergency situation on board; and, iii) asks the driver to park at the shoulder of the road and take a vasodilation pill from a built-in compartment. The developed system has undergone a rigorous bench-testing procedure and awaits to be tested in a real-life simulation. The originality of this device resides in the automation of the necessary tasks that a driver has to do in case of such emergency with minimum effort. Thus, the developed device provides an easy-to-use heart attack detection means that helps people with a history of chronic heart diseases to avoid car accidents while behind the steering wheel.