Superresolution Line Scan Image Sensor for Multimodal Microscopy.

A low-cost contact scanning microscope is presented which performs optical imaging of millimeter-scale samples with multiple sensory modalities at a spatial resolution better than the pixel size in both x and y dimensions. The 7.5 mm 3.2 mm 0.35 m CMOS image sensor is comprised of 214 scanning lines of 256 pixels, each line horizontally shifted by 300 nm with respect to the adjacent lines. When scanning in the y dimension, this results in a staircase-like staggered-pixels organization with an effective spatial resolution in the x dimension of less than the pixel size, with a theoretical limit of 300 nm, subject to the light diffraction limit and to photodiode size-dependent spatial aliasing. The height of the resulting pixel "staircases" is capped at 2.5 mm by wrapping the 215th row back to the first row, yielding an approximately 2 mm 2.5 mm instantaneous scanning window size. The spatial resolution in the y dimension is set by the sample scanning rate and the frame rate, subject to the same limitations. Integration of multiple scanning lines naturally lends itself to the inclusion of multiple sensory modalities, with five modalities included as an example: High-resolution (up to 300 nm), fluorescence-sensitive, and triple-orientation light polarization-sensitive pixels. The resulting modified scanning pattern is digitized by on-chip column-parallel 2nd order Delta-Sigma ADCs with ENOB of 9.1 and is reconstructed into a full-resolution image in software. Experimental measurements, where contact-scanning is emulated by the sample image moving on an LCD monitor and projected through a lens, support the validity of the presented concept.

SecureMed: Secure Medical Computation Using GPU-Accelerated Homomorphic Encryption Scheme.

Sharing the medical records of individuals among healthcare providers and researchers around the world can accelerate advances in medical research. While the idea seems increasingly practical due to cloud data services, maintaining patient privacy is of paramount importance. Standard encryption algorithms help protect sensitive data from outside attackers but they cannot be used to compute on this sensitive data while being encrypted. Homomorphic Encryption presents a very useful tool that can compute on encrypted data without the need to decrypt it. In this paper, we describe an optimized NTRU-based implementation of the GSW homomorphic encryption scheme. Our results show a factor of 58 × improvement in CPU performance compared to other recent work on encrypted medical data under the same security settings. Our system is built to be easily portable to GPUs resulting in an additional speedup of up to a factor of 104 × (and 410 ×) to offer an overall speedup of 6085 × (and 24011 ×) using a single GPU (or four GPUs), respectively.

CMOS spectrally-multiplexed FRET-on-a-chip for DNA analysis.

A spectral-multiplexed fluorescence contact imaging microsystem for DNA analysis is presented. The microsystem integrates a filterless CMOS Color PhotoGate (CPG) sensor that exploits the polysilicon gate as an optical filter, and therefore does not require an external color filter. The CPG is applied to fluorescence-based transduction in a spectrally multiplexed format by differentiating among multiple emission bands, hence replacing the functionality of a bank of emission filters. A microsystem has been quantitatively modeled and prototyped based on the CPG fabricated in a standard 0.35 µm CMOS technology. The multi-color imaging capability of the microsystem in analyzing DNA targets has been validated in the detection of marker gene sequences for spinal muscular atropy disease and Escherichia coli (E. coli). Spectral-multiplexing enables the two DNA targets to be simultaneously detected with a measured detection limits of 240 nM and 210 nM for the two target concentrations at a sample volume of 10 µL for the green and red transduction channels, respectively.

CMOS tunable-wavelength multi-color photogate sensor.

A CMOS tunable-wavelength multi-color photogate (CPG) sensor is presented. Sensing of a small set of well-separated wavelengths (e.g., > 50 nm apart) is achieved by tuning the spectral response of the device with a bias voltage. The CPG employs the polysilicon gate as an optical filter, which eliminates the need for an external color filter. A prototype has been fabricated in a standard 0.35 µm digital CMOS technology and demonstrates intensity measurements of blue (450 nm), green (520 nm), and red (620 nm) illumination with peak signal-to-noise ratios (SNRs) of 34.7 dB , 29.2 dB, and 34.8 dB, respectively. The prototype is applied to fluorescence detection of green-emitting quantum dots (gQDs) and red-emitting quantum dots (rQDs). It spectrally differentiates among multiple emission bands, effectively implementing on-chip emission filtering. The prototype demonstrates single-color measurements of gQD and rQD concentrations to a detection limit of 24 nM, and multi-color measurements of solutions containing both colors of QDs to a detection limit of 90 nM and 120 nM of gQD and rQD, respectively.