Lab-on-a Chip platforms for manipulation and sensing of biological entities.
advent and continuous scaling of micro-fabrication technology has offered new
capabilities in realization of Lab-on-a-Chip (LoC) platforms. More specifically, they
offer the potential to perform spatial control and manipulation of biological targets
with embedded transducers to sense and process them. If such platforms can be integrated
transistors and readout circuitry, it has ... read morethe potential to offer truly miniaturized
solution. From a standpoint of LoC platform design, we present two platforms for
biosensing and manipulation of cells. First, I present a CMOS LoC platform for DEP
trapping and repositioning of cells and microorganisms. Given the need to perform the
operation in real-time, in-situ impedance monitoring of the trapping function is
demonstrated. We present EM simulation results for DEP force and reorientation by novel
three-dimensional (3D) octapole electrode geometry, all realized in a commercial
0.5µm CMOS process. This CMOS LoC platform integrates an analog front end for
impedance monitoring of biological targets as they are repositioned on electrodes due to
DEP in real-time. Experimental results with yeast cells validate the design. Second, I
present a compact AC susceptometer for biosensing based on Brownian relaxation of
magnetic nanoparticle (MNP). A novel multiplexed sensing scheme based on the measurement
of the magnetic susceptibility of the affinity captured target molecules on magnetic
nanoparticles in liquid suspension is proposed. The AC magnetic susceptibility provides
a measurement of Brownian relaxation behavior of biomolecules bound to MNPs that is
related to its hydrodynamic size. The miniaturized AC susceptometer exhibits high
sensitivity in magnetic fields as low as 10 µT for 1 mg ml−1 concentration
and 5 µl volume, and is fully software programmable. The capability of biological
sensing using the proposed scheme has been demonstrated in proof of principle using the
binding of biotinylated horseradish peroxidase (HRP) to streptavidin-coated MNPs. The
technique and instrument are readily compatible with lab-on-chip applications for
point-of-care medical applications.
Thesis (Ph.D.)--Tufts University, 2015.
Submitted to the Dept. of Electrical Engineering.
Advisor: Sameer Sonkusale.
Committee: Anil Saigal, Usman Khan, and Youngho Suh.
Keywords: Electrical engineering, and Biomedical engineering.read less