We demonstrate a high performance microfabricated FACS system with highly integrated microfluidics, optics, acoustics, and electronics. Single cell manipulation at a high speed is made possible by the fast response time (~0.1 ms) of the integrated PZT actuator and the nozzle structure at the sorting junction. A Teflon AF-coated optofluidic waveguide along the microfluidic channel guides the illumination light, enabling multi-spot detection, while a novel space-time coding technology enhances the detection sensitivity of the μFACS system. The real-time control loop system is implemented using a field-programmable-gate-array (FPGA) for automated and accurate sorting. The μFACS achieves a high purification enrichment factor: up to ~230 fold for both polystyrene microbeads and suspended human mammalian cells (K562) at a high throughput (>1000 cells s−1). The sorting mechanism is independent of cell properties such as size, density, and shape, thus the presented system can be applied to sort out any pure sub-populations. This new lab-on-a-chip FACS system, therefore, holds promise to revolutionize microfluidic cytometers to meet cost, size, and performance goals.

Microfluidics and photonics come together to form a field commonly referred to as ‘optofluidics’. Flow cytometry provides the field with a technology base from which both microfluidic and photonic components be developed and integrated into a useful device. This article reviews some of the more recent developments to familiarize a reader with the current state of the technologies and also highlights the requirements of the device and how researchers are working to meet these needs. A microfluidic flow cytometer protoype employing on-chip lenses for illumination and light collection in conjunction with a microfluidic sample flow system for device miniaturization.

We demonstrate a low-power (<0.1 mW), low-voltage (<10 Vp-p) on-chip piezoelectrically actuated micro-sorter that can deflect single particles and cells at high-speed. With rhodamine in the stream, switching of flow between channels can be visualized at high actuation frequency (~1.7 kHz). The magnitude of the cell deflection can be precisely controlled by the magnitude and waveform of input voltage. Both simulation and experimental results indicate that the drag force imposed on the suspended particle/cell by the instantaneous fluid displacement can alter the trajectory of the particle/cell of any size, shape, and density of interest in a controlled manner. The open-loop E. Coli cell deflection experiment demonstrates that the sorting mechanism can produce a throughput of at least 330 cells/s, with a promise of a significantly higher throughput for an optimized design. To achieve close-loop sorting operation, fluorescence detection, real-time signal processing, and field-programmable-gate-array (FPGA) implementation of the control algorithms were developed to perform automated sorting of fluorescent beads. The preliminary results show error-free sorting at a sorting efficiency of ~70%. Since the piezoelectric actuator has an intrinsic response time of 0.1–1 ms and the sorting can be performed under high flowrate (particle speed of ~1–10 cm/s), the system can achieve a throughput of >1,000 particles/s with high purity.

When attempting to probe the genetic makeup of diverse bacterial communities that elude cell culturing, researchers face two primary challenges: isolation of rare bacteria from microbial samples and removal of contaminating cell-free DNA. We report a compact, low-cost, and high-performance microfabricated fluorescence-activated cell sorting (μFACS) technology in combination with a tyramide signal amplification fluorescence in situ hybridization (TSA-FISH) to address these two challenges. The TSA-FISH protocol that was adapted for flow cytometry yields a 10-30-fold enhancement in fluorescence intensity over standard FISH methods. The μFACS technology, capable of enhancing its sensitivity by ~18 dB through signal processing, was able to enrich TSA-FISH-labeled E. coli cells by 223-fold. The μFACS technology was also used to remove contaminating cell-free DNA. After two rounds of sorting on E. coli mixed with λ-phage DNA (10 ng/μL), we demonstrated over 100,000-fold reduction in λ-DNA concentration. The integrated μFACS and TSA-FISH technologies provide a highly effective and low-cost solution for research on the genomic complexity of bacteria as well as single-cell genomic analysis of other sample types.

We report the achievement of a highly versatile imager consisting of a tunable fluidic lens with a wide tuning range and three fixed lenses. The device has a volume of less than 1 cm(3) and a short total track length of 12.5 cm. It can function as a regular camera with an ultrawide autofocusing range and as a microscope with 3 microm resolution.

We describe a fluorescent detection technique for a lab-on-a-chip flow cytometer. Fluorescent emission is encoded into a time-dependent signal as a fluorescent cell or bead traverses a waveguide array with integrated spatial filters and color filters. Different from conventional colored filters with well-defined transmission spectral window, the integrated color filters are designed to have broad transmission characteristics, similar to the red-green-blue photoreceptors in the retina of human eye. This unique design allows us to detect multiple fluorescent colors with only three color filters based on the technique of color-space-time coding using only one single photomultiplier tube or avalanche photodetector.

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Abstract. This work reports a miniaturized laparoscopic zoom camera that can significantly improve vision for minimally invasive surgery ͑MIS͒, also known as laparoscopic surgery. The laparoscopic zoom camera contains bioinspired fluidic lenses that can change curvature and focal length in a manner similar to the crystalline lenses in human eyes. The traditional laparoscope is long, rigid, and made of fixed glass lenses with a fixed field of view. The constricted vision of a laparoscope is often an inconvenience and plays a role in many surgical injuries. To further advance MIS technology, we developed a new type of laparoscopic camera that has a total length of less than 17 mm, greater than 4ϫ optical zoom, and 100 times higher sensitivity than today's laparoscope allowing it to work under illumination as low as 300 lux. All these unique features are enabled by the technology of bioinspired fluidic lenses having a dynamic range over 100 diopters and being convertible between a convex and concave shape.