Zhenyu Li

George Washington University | GW · Department Biomedical Engineering

A prerequisite for single cell study is the capture and isolation of individual cells. In microfluidic devices, cell capture is often achieved by means of trapping. While many microfluidic trapping techniques exist, hydrodynamic methods are particularly attractive due to their simplicity and scalability. However, current design guidelines for singl...

Microfluidics and lab-on-a-chip technologies have made it possible to manipulate small volume liquids with unprecedented resolution, automation and integration. However, most current microfluidic systems still rely on bulky off-chip infrastructures such as compressed pressure sources, syringe pumps and computers to achieve complex liquid manipulati...

Microarray devices are powerful for detecting and analyzing biological targets. However, the potential of these devices may not be fully realized due to the lack of optimization of their design and implementation. In this work, we consider a microsphere-trap array device by employing microfluidic techniques and a hydrodynamic trapping mechanism. We...

A flexible technology is proposed to integrate smart electronics and microfluidics all embedded in an elastomer package. The microfluidic channels are used to deliver both liquid samples and liquid metals to the integrated circuits (ICs). The liquid metals are used to realize electrical interconnects to the IC chip. This avoids the traditional IC p...

This paper describes the design, fabrication, and preliminary testing of a low-cost, easy to manufacture microfluidics cartridge capable of fluid storage and manipulation through a custom pressure-driven check valve. Cartridge components are fabricated using a desktop CNC and laser cutter, the check valve is fabricated using PDMS in a custom acryli...

Biofilm infections represent a major public health threat due to their high tolerance to antimicrobials and the lack of specific anti-biofilm drugs. To develop such drugs, it is crucial to have high-throughput biofilm growth systems that can emulate in vivo conditions without the cost and complexity of animal models. However, no current biofilm rea...

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) represent a scalable experimental model relevant to human physiology. Oxygen consumption of hiPSC-CMs has not been studied in high-throughput (HT) format plates used in pre-clinical studies. Here, we provide comprehensive characterization and validation of a system for HT long-t...

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) represent a scalable experimental model relevant to human physiology. Oxygen consumption of hiPSC-CMs has not been studied in high-throughput (HT) format plates used in pre-clinical studies. Here, we provide comprehensive characterization and validation of a system for HT long-t...

This paper describes the design, fabrication, and preliminary testing of a low-cost, easy to manufacture microfluidics cartridge capable of fluid storage and manipulation through a custom pressure-driven check valve. Cartridge components are fabricated using a desktop CNC and laser cutter, the check valve is fabricated using PDMS in a custom acryli...

For metabolically active cells like cardiomyocytes, a balanced state of oxygen supply and demand is crucial for basic cell function. Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are a valuable experimental model due of their scalability and relevance to human physiology. Oxygen consumption and availability have not been c...

Background One of the most common pollutants in residences due to gas appliances, NO2 has been shown to increase the risk of asthma attacks after small increases in short term exposure. However, standard environmental sampling methods taken at the regional level overlook chronic intermittent exposure due to lack of temporal and spatial granularity....

The ability to acquire multi-lead electrocardiograms (ECGs) in a timely manner is critical to patient survival and better clinical outcomes after acute cardiac events, including myocardial infarctions (MI). However, current wearable ECG devices do not provide the traditional 12-lead information needed for clinical MI diagnosis. Here, we report, to...

This paper presents a cloud-connected indoor air quality sensor system that can be deployed to patients' homes to study personal microenvironmental exposure for asthma research and management. The system consists of multiple compact sensor units that can measure residential NO2, ozone, humidity, and temperature at one minute resolution and a cloud...

This work demonstrates a novel high-throughput (HT) microfluidics-enabled uninterrupted perfusion system (HT-μUPS) and validates its use with chronic all-optical electrophysiology in human excitable cells. HT-μUPS consists of a soft multichannel microfluidic plate cover which could button on a commercial HT 96-well plate. Herein, we demonstrate the...

Non-invasive continuous alcohol (ethanol) monitoring has potential applications in both population research and in clinical management of acute alcohol intoxication or chronic alcoholism. Current wearable monitors based on transdermal alcohol content (TAC) sensing have limited accessibility and blood alcohol content (BAC) quantification accuracy. H...

This paper presents a cloud-connected indoor air quality sensor system that can be deployed to patients’ homes to study personal microenvironmental exposure for asthma research and management. The system consists of multiple compact sensor units that can measure residential NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://...

This work demonstrates a novel high-throughput (HT) microfluidics-enabled uninterrupted perfusion system (HT-μUPS) and validates its use with chronic all-optical electrophysiology in human excitable cells. HT-μUPS consists of a soft multichannel microfluidic plate cover which could button on a commercial HT 96-well plate. Herein, we demonstrate the...

Non-invasive continuous alcohol monitoring has potential applications in both population research and in clinical management of acute alcohol intoxication or chronic alcoholism. Current wearable monitors based on transdermal alcohol content (TAC) sensing are relatively bulky and have limited quantification accuracy. Here we describe the development...

In article number 1900138, Shiqi Guo, Zhenyu Li, Yujie Xiong, and co‐workers develop a toxic gas sensing epidermal device for patients with asthma based on 2D materials with a wireless connection. This route is used to timely send data to the smartphone as well as cloud terminal uploading for further researching, sharing, and recording. The authors...

Toxic gases such as NO2 and irritant gases such as NH3 are two of the harshest aspects that trigger the exacerbation of the respiratory system for asthma patients. Monitoring and recording high‐risk gases are very important for tracking disease and alerting patients because humans can be exposed to a vulnerable environment with inconspicuous gases....

Mechanistic studies and personalized managements of pediatric asthma require objective measures of environmental exposure metrics correlated with patient's physiological responses. Here we report a cloud-based wearable IoT sensor system which can measure an asthma patient's exposure to aldehydes, a known class of airway irritants, in real-life sett...

Mechanistic studies of pediatric asthma require objective measures of environmental exposure metrics correlated with physiological responses. Here we report a cloud-based wearable IoT sensor system which can measure an asthma patient's exposure to aldehydes, a known class of airway irritants, in real-life settings. The wrist-watch form sensor measu...

Human cardiac slices have emerged as a promising model of the human heart for scientific research and drug testing. Retaining the normal tissue architecture, a multi-cell type environment, and the native extracellular matrix, human cardiac slices faithfully replicate organ-level adult cardiac physiology. Previously, we demonstrated that human cardi...

The development of medical-device technology is constrained by the financial and ethical considerations of animal testing and clinical trials. Organ-on-a-chip systems are being developed to speed up drug development, yet there has been little recognition or support for the use of this technology in the development and testing of medical devices. In...

We present a novel, microfluidic platform that integrates human tears (1µL) with commercial contact lens material to provide personalized assessment of lens care solution performance. This device enabled the detection of significant differences in cleaning and disinfection outcomes between subjects and between biofilm vs. planktonic bacteria, respe...

Block co-polymer surfactants have been used for cleaning hydrogel medical devices that contact the body (eg contact lenses) because of their biocompatibility. This work examined the relationship between concentration and detergency of two non-ionic polymeric surfactants (Pluronic F127 and Triton X-100) for cleaning protein soil, with anionic surfac...

Hemoglobin (Hb) is an important analyte in medicine, forensics, and research. One area of crucial need for real-world Hb quantitation is the validation and quality control (QC) of reprocessed medical device cleaning. Here, we show how a microplate reader and colorimetric blood test strips can be used to quantitate nanogram (ng) quantities of Hb in...

Video showing the bead based immunoassay in a microfluidic hydrodynamic trapping array.

Video showing the handheld microfluidic liquid handling system in operation for a bead based sandwich immunoassay.

Hydrogels are an increasingly important class of medical device materials that enable diverse and unique function, but can also be subject to significant biofouling and contamination. Although it is challenging to accurately quantify protein biofouling in hydrogels, spectroscopic detection of fluorescently labeled proteins is one method with the po...

Antibody-based proteomics is an enabling technology that has significant implications for cancer biomarker discovery, diagnostic screening, prognostic and pharmacodynamic evaluation of disease state, and targeted therapeutics. Quantum dot based fluoro-immunoconjugates possess promising features toward realization of this goal such as high photostab...

We propose an analytical framework to build a microfluidic microsphere-trap array device that enables simultaneous, efficient, and accurate screening of multiple biological targets in a single microfluidic channel. By optimizing the traps' geometric parameters, the trap arrays in the channel of the device can immobilize microspheres of different si...

Antibody-based proteomics is an enabling technology that has significant implications for cancer biomarker discovery, diagnostic screening, prognostic and pharmacodynamic evaluation of disease state, and targeted therapeutics. Quantum dot based fluoro-immunoconjugates possess promising features toward realization of this goal such as high photostab...

This paper presents a liquid metal based on-chip optofluidic grating spectrograph integrated with polydimethylsiloxane (PDMS) microfluidics for biomedical applications such as handheld fluorescence-actuated cell sorting, fluorescence immunosensing and Raman spectroscopy. We designed a Czerny-Turner spectrograph with 1.4nm spectral resolution, 300nm...

https://www.google.com/patents/US20130243655

Computational fluid dynamic (CFD) simulation is a powerful tool in the design and implementation of microfluidic systems, especially for systems that involve hydrodynamic behavior of objects such as functionalized microspheres, biological cells, or biopolymers in complex structures. In this work, we investigate hydrodynamic trapping of microspheres...

A novel rectangular shape differential CMOS split-drain Hall Effect magnetic field-effect transistor (MAGFET) was designed and fabricated employing a CMOS 0.5 μm process. The detection and monitoring of single 2.8 μm diameter magnetic beads was successfully performed using this MAGFET design. Based on the device modeling, simulation and the signal...

We have demonstrated flexible packaging and integration of CMOS IC chips with PDMS microfluidics. Microfluidic channels are used to deliver both liquid samples and liquid metals to the CMOS die. The liquid metals are used to realize electrical interconnects to the CMOS chip. As a demonstration we integrated a CMOS magnetic sensor die and matched PD...

We build a microfluidic trap-based microsphere array device. In the device, we design a novel geometric structure of the trap array and employ the hydrodynamic trapping mechanism to immobilize the microspheres. We develop a comprehensive and robust framework to optimize the values of the geometric parameters to maximize the microsphere arrays' pack...

Microsphere arrays can be used to effectively detect, identify, and quantify biological targets, such as mRNAs, proteins, antibodies, and cells. In this work, we design a microfluidic microsphere-trap array device that enables simultaneous, efficient, and accurate screening of multiple targets on a single platform. Different types of targets are ca...

Supplementary Information

A Single-Photon Avalanche Diode (SPAD) design solution that can be implemented in a low cost CMOS process, n-well 0.5μm process, is proposed. This SPAD design used the lateral diffusion of the n-wells to create a low n doping density area as the guard ring to prevent the premature breakdown at the edge of SPAD. Through the TCAD simulation and fabri...

We demonstrated an active optofluidic coupled micro-ring resonator for biosensing on a monolithic poly(dimethylsiloxane) (PDMS) chip. Biotin detection limit of ~20pm was achieved with a single mode liquid-core waveguide based micro-ring cavity.

https://www.google.com/patents/US20120091235

We proposed a portable molecular diagnostic tool implemented by CMOS and Microfluidic technology for the early HIV diagnosis. Our system diagnoses HIV by detecting the P24 antigen concentration in blood sample. We labeled P24 antigens with chemiluminescence signal, which can be detected by our CMOS photon detector. We designed the single photon ava...

Recently, Single Photon Avalanche Diode (SPAD) draws attentions because of its applications in bio-molecule detection [1] and optical communication [2]. In order to reduce the cost and improve the detection throughput, one trend is to integrate large number of SPAD pixels with readout circuit and signal processing circuit on one silicon chip. In th...

Recently, photo conductive properties of Graphene have been explored theoretically in [1] and experimentally in [2, 3]. In this paper we propose to build an optical bio sensor using Graphene Nano Ribbon (GNR). It is known that the band gap of GNR is controlled by the width of ribbon. The relation between the band gap and the width of the GNR is giv...

"Optofluidics" is the marriage of optics, optoelectronics and nanophotonics with fluidics. Such integration represents a new approach for dynamic manipulation of optical properties at length scales both greater than and smaller than the wavelength of light with applications ranging from reconfigurable photonic circuits to fluidically adaptable opti...

http://www.google.com/patents/US7817698

An amplifier design for broadband Mid-IR buried-hetero (BH) structure epitaxial laser is presented, and external cavity design based on this amplifier is described. Spectroscopy results characterizing such single frequency lasers are demonstrated with whispering gallery mode CaF2 disc/ball, saturated absorption in hollow waveguide and direct chemic...

We describe a multi-color microfluidic dye laser operating in whispering gallery mode based on a train of alternating droplets containing solutions of different dyes; this laser is capable of switching the wavelength of its emission between 580 nm and 680 nm at frequencies up to 3.6 kHz-the fastest among all dye lasers reported; it has potential ap...