Hamidreza Afzal (Member, IEEE) received the B.Sc. degree in electrical engineering from the K. N. Toosi University of Technology, Tehran, Iran, in 2015, and the M.S. degree in electrical engineering from the Sharif University of Technology, Tehran, in 2017. He received his Ph.D. degree with the Department of Electrical Engineering, University of California at Davis, Davis, CA, USA in 2024. He is currently a postdoctoral researcher at the University of California, Berkeley. His research interests include radio frequency (RF), millimeter-wave (mm-wave), and terahertz integrated...
This paper introduces a microfluidics platform embedded within a silicon chip implemented in CMOS technology. The platform utilizes a one-step wet etching method to create fluidic channels by selectively removing CMOS back-end-of-line (BEOL) routing metals. We term our technique “subtractive” microfluidics, to complement those fabricated with additive manufacturing. Three types of structures are presented in a TSMC I80-nm CMOS chip: (1) passive microfluidics in the form of a micro-mixer and a 1: 64 splitter, (2) fluidic channels with embedded ion-sensitive field-effect transistors (ISFETs...
We have previously demonstrated electrochemical circuits for measuring the concentration of various biomolecules and drugs using structure-switching aptamers. Structure-switching aptamers are single-stranded nucleic acids that can be sequenced to exhibit conformational changes when bound to specific biomolecules. By conjugating aptamers with a redox reporter, voltammetry or amperometry-based measurements can be applied and signals in the nano to pico-amp scale can be captured using transimpedance amplifiers (TIA). Because the signals of interest are very small, noise-cancellation...
Integrating microelectronics with microfluidics, especially those implemented in silicon-based CMOS technology, has driven the next generation of in vitro diagnostics. This CMOS/microfluidics platform offers close interfaces between electronics and biological samples and tight integration of readout circuits with multi-channel microfluidics, both of which are crucial factors in achieving enhanced sensitivity and detection throughput. Importantly, conventionally bulky benchtop instruments are now being transformed into millimeter-sized form factors at low cost, making the deployment for...
Aptamers, often referred to as ""synthetic antibodies,"" are nucleic acid-based molecules that selectively bind to target analytes in complex biological samples, such as whole blood. They can undergo reversible structural changes upon binding, allowing for real-time detection. By conjugating electroactive reporters to aptamers, these structural changes can be monitored electrochemically. Due to their reagentless nature, these biosensors are highly suitable for both in vitro and in vivo applications. Our lab specializes in aptamer-based sensors and has published several studies on their...
Current quantum processor units (QPUs) have achieved over 1,000 qubits (e.g., IBM's Condor processor). However, scaling quantum platforms toward 1 million qubits demands breakthroughs in quantum hardware, connectivity, error correction, and system architecture. To address the scalability of quantum interconnects, Cryo-CMOS control and readout circuits have demonstrated efficacy in reducing wiring complexity, latency, and thermal loads. However, the CMOS circuits limit the active heat load to 1–2 mW/qubit, imposing a limit of approximately 1,000 qubits in state-of-the-art dilution...
Endoscopic ultrasound imaging systems require compact, low-power probes with a dense array of sensing elements. At the same time, the cabling inside the probe tube that interfaces with the external processing unit should be minimal. State-of-the-art ultrasound imagers that utilize CMUTs and PMUTs require integrating each transducer’s power-hungry analog frontend on probe, making it more difficult to satisfy the safe power limit. To address this, we propose the use of silicon microring resonators (MRRs) as ultrasound sensors. Their small element size (10-20 μm in diameter) allows us to...
The Electrochemical Aptamer-based (E-AB) sensors provide continuous and real-time monitoring of specific target molecules, including proteins, antibiotics, neurotransmitters, and more. Due to the cost-effectiveness compared to enzyme sensing assays, E-AB platforms hold significant promise for point-of-care devices and precision medicine. However, sensitivity remains a challenge, particularly in the complicated environment, such as blood and serum. While research has achieved a noise level in the picoampere range, enhancing sensitivity is crucial for detecting trace amounts of certain...
