Integrated Sensors for Biomedical Applications

Speaker Name: 
Efthymios Papageorgiou
Speaker Title: 
Ph.D Candidate
Speaker Organization: 
UC Berkeley
Start Time: 
Monday, March 4, 2019 - 10:40am
End Time: 
Monday, March 4, 2019 - 11:40am
Holger Schmidt

Abstract: There are numerous challenges facing the medical community that can benefit from innovative microelectronic devices and systems. For instance, there is a large need for small-scale sensors that are either implantable or designed for intraoperative use. The design of these sensors requires experience in the synthesis of electronic, optical, and biomedical engineering. In particular, there is a persistent need for such an intraoperative device that is capable of detecting microscopic residual disease (MRD), small clusters of hundreds to thousands of cancer cells left behind after the gross tumor is removed during a surgical resection. Fluorescence microscopes for intraoperative navigation lack the necessary sensitivity for imaging MRD and are too bulky to maneuver within a 1–3 cm diameter tumor cavity.


We have developed integrated circuit-based image sensors that can be easily fabricated to any convenient size scale to fit inside a resection cavity. We have enhanced the resolution of these contact image sensors using optical microstructures, called angle-selective gratings (ASGs), fabricated in the metal layers of the CMOS process. The ASGs enable the detection of clusters of cancer containing as few as 25 cells. We have demonstrated detection of residual breast tumor in mice. Using a thin-film amorphous silicon absorption filter in conjunction with the sensor, we maintain greater than 105 rejection of the fluorescence excitation light. We estimate the original image using deconvolution algorithms incorporating the angle-selectivity response of the ASGs. This work can be extended by incorporating additional computational techniques along with structured illumination and multispectral imaging to further enhance image resolution. Photoactivatable fluorophores can be used to provide axial resolution. Moreover, the general-purpose nature of our imaging device and its modality allow its extension not only to other medical applications, such as radiotherapy, but also to non-medical applications, such as fingerprint sensing and scanning.


Biography: Efthymios Papageorgiou received his B.Sc. from Columbia University in 2014 where he worked with Prof. Yannis Tsividis on continuous time hybrid analog-digital circuits. Since then, he has been working towards a Ph.D. in Prof. Bernhard Boser’s research group in the Department of Electrical Engineering and Computer Sciences at UC Berkeley. He is co-advised by Prof. Mekhail Anwar at UCSF. He will graduate in Spring 2019. His research is focused on biomedical circuits and systems, especially concerning devices for intraoperative cancer detection. He has received the Edwin Howard Armstrong Memorial Award from Columbia University in 2014, the Berkeley Fellowship for Graduate Study in 2014, the ADI Outstanding Student Designer Award in 2016, and the NSF Fellowship for Graduate Study in 2016.