1
|
A Cataño J, Farthing S, Mascarenhas Z, Lake N, Yarlagadda PKDV, Li Z, Toh YC. A User-Centric 3D-Printed Modular Peristaltic Pump for Microfluidic Perfusion Applications. MICROMACHINES 2023; 14:mi14050930. [PMID: 37241553 DOI: 10.3390/mi14050930] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/17/2023] [Accepted: 04/23/2023] [Indexed: 05/28/2023]
Abstract
Microfluidic organ-on-a-chip (OoC) technology has enabled studies on dynamic physiological conditions as well as being deployed in drug testing applications. A microfluidic pump is an essential component to perform perfusion cell culture in OoC devices. However, it is challenging to have a single pump that can fulfil both the customization function needed to mimic a myriad of physiological flow rates and profiles found in vivo and multiplexing requirements (i.e., low cost, small footprint) for drug testing operations. The advent of 3D printing technology and open-source programmable electronic controllers presents an opportunity to democratize the fabrication of mini-peristaltic pumps suitable for microfluidic applications at a fraction of the cost of commercial microfluidic pumps. However, existing 3D-printed peristaltic pumps have mainly focused on demonstrating the feasibility of using 3D printing to fabricate the structural components of the pump and neglected user experience and customization capability. Here, we present a user-centric programmable 3D-printed mini-peristaltic pump with a compact design and low manufacturing cost (~USD 175) suitable for perfusion OoC culture applications. The pump consists of a user-friendly, wired electronic module that controls the operation of a peristaltic pump module. The peristaltic pump module comprises an air-sealed stepper motor connected to a 3D-printed peristaltic assembly, which can withstand the high-humidity environment of a cell culture incubator. We demonstrated that this pump allows users to either program the electronic module or use different-sized tubing to deliver a wide range of flow rates and flow profiles. The pump also has multiplexing capability as it can accommodate multiple tubing. The performance and user-friendliness of this low-cost, compact pump can be easily deployed for various OoC applications.
Collapse
Affiliation(s)
- Jorge A Cataño
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia
- Centre for Biomedical Technologies, Queensland University of Technology, Kelvin Grove 4059, Australia
| | - Steven Farthing
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia
| | - Zeus Mascarenhas
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia
| | - Nathaniel Lake
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia
| | - Prasad K D V Yarlagadda
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia
- Centre for Biomedical Technologies, Queensland University of Technology, Kelvin Grove 4059, Australia
- School of Engineering, University of Southern Queensland, Springfield Central 4300, Australia
| | - Zhiyong Li
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia
- Centre for Biomedical Technologies, Queensland University of Technology, Kelvin Grove 4059, Australia
| | - Yi-Chin Toh
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia
- Centre for Biomedical Technologies, Queensland University of Technology, Kelvin Grove 4059, Australia
- Max Planck Queensland Centre (MPQC) for the Materials Science of Extracellular Matrices, Queensland University of Technology, Kelvin Grove 4059, Australia
- Centre for Microbiome Research, Queensland University of Technology, Woolloongabba 4102, Australia
| |
Collapse
|
2
|
Dradrach K, Zmyślony M, Deng Z, Priimagi A, Biggins J, Wasylczyk P. Light-driven peristaltic pumping by an actuating splay-bend strip. Nat Commun 2023; 14:1877. [PMID: 37015926 PMCID: PMC10073117 DOI: 10.1038/s41467-023-37445-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 03/15/2023] [Indexed: 04/06/2023] Open
Abstract
Despite spectacular progress in microfluidics, small-scale liquid manipulation, with few exceptions, is still driven by external pumps and controlled by large-scale valves, increasing cost and size and limiting complexity. By contrast, optofluidics uses light to power, control and monitor liquid manipulation, potentially allowing for small, self-contained microfluidic devices. Here we demonstrate a soft light-propelled actuator made of liquid crystal gel that pumps microlitre volumes of water. The strip of actuating material serves as both a pump and a channel leading to an extremely simple microfluidic architecture that is both powered and controlled by light. The performance of the pump is well explained by a simple theoretical model in which the light-induced bending of the actuator competes with the liquid's surface tension. The theory highlights that effective pumping requires a threshold light intensity and strip width. The proposed system explores the benefits of shifting the complexity of microfluidic systems from the fabricated device to spatio-temporal control over stimulating light patterns.
Collapse
Affiliation(s)
- Klaudia Dradrach
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom.
- Faculty of Physics, University of Warsaw, Warsaw, Poland.
| | - Michał Zmyślony
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Zixuan Deng
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland
| | - Arri Priimagi
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland
| | - John Biggins
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom.
| | | |
Collapse
|
3
|
|
4
|
Cantoni F, Werr G, Barbe L, Porras AM, Tenje M. A microfluidic chip carrier including temperature control and perfusion system for long-term cell imaging. HARDWAREX 2021; 10:e00245. [PMID: 35607686 PMCID: PMC9123440 DOI: 10.1016/j.ohx.2021.e00245] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 10/26/2021] [Accepted: 10/30/2021] [Indexed: 06/03/2023]
Abstract
Microfluidic devices are widely used for biomedical applications but there is still a lack of affordable, reliable and user-friendly systems for transferring microfluidic chips from an incubator to a microscope while maintaining physiological conditions when performing microscopy. The presented carrier represents a cost-effective option for sustaining environmental conditions of microfluidic chips in combination with minimizing the device manipulation required for reagent injection, media exchange or sample collection. The carrier, which has the outer dimension of a standard well plate size, contains an integrated perfusion system that can recirculate the media using piezo pumps, operated in either continuous or intermittent modes (50-1000 µl/min). Furthermore, a film resistive heater made from 37 µm-thick copper wires, including temperature feedback control, was used to maintain the microfluidic chip temperature at 37 °C when outside the incubator. The heater characterisation showed a uniform temperature distribution along the chip channel for perfusion flow rates up to 10 µl/min. To demonstrate the feasibility of our platform for long term cell culture monitoring, mouse brain endothelial cells (bEnd.3) were repeatedly monitored for a period of 10 days, demonstrating a system with both the versatility and the potential for long imaging in microphysiological system cell cultures.
Collapse
|
5
|
Forouzandeh F, Alfadhel A, Arevalo A, Borkholder DA. A review of peristaltic micropumps. SENSORS AND ACTUATORS. A, PHYSICAL 2021; 326:112602. [PMID: 35386682 PMCID: PMC8979372 DOI: 10.1016/j.sna.2021.112602] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
This report presents a review of progress on peristaltic micropumps since their emergence, which have been widely used in many research fields from biology to aeronautics. This paper summarizes different techniques that have been used to mimic this elegant physiological transport mechanism that is commonly found in nature. The analysis provides definitions of peristaltic micropumps and their different features, distinguishing them from other mechanical micropumps. Important parameters in peristalsis are presented, such as the operating frequency, stroke volume, and various actuation sequences, along with introducing design rules and analysis for optimizing actuation sequences. Actuation methods such as piezoelectric, motor, pneumatic, electrostatic, and thermal are discussed with their advantages and disadvantages for application in peristaltic micropumps. This review evaluates research efforts over the past 30 years with comparison of key features and outputs, and suggestions for future development. The analysis provides a starting point for researchers designing peristaltic micropumps for a broad range of applications.
Collapse
Affiliation(s)
- Farzad Forouzandeh
- Corresponding author at: Microsystem Engineering, Kate Gleason College of Engineering, Rochester Institute of Technology, 168 Lomb Memorial Drive, Rochester, NY 14623, USA.
| | | | | | | |
Collapse
|
6
|
Wang Y, Seidel M. Integration of 3D Hydrodynamic Focused Microreactor with Microfluidic Chemiluminescence Sensing for Online Synthesis and Catalytical Characterization of Gold Nanoparticles. SENSORS 2021; 21:s21072290. [PMID: 33805892 PMCID: PMC8036713 DOI: 10.3390/s21072290] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/19/2021] [Accepted: 03/23/2021] [Indexed: 11/16/2022]
Abstract
Chemiluminescence assays have shown great advantages compared with other optical techniques. Gold nanoparticles have drawn much attention in chemiluminescence analysis systems as an enzyme-free catalyst. The catalytic activity of gold nanoparticles for chemiluminescence sensing depends on size, shape and the surface charge property, which is hard to characterize in batches. As there is no positive or negative correlation between chemiluminescence signals and sizes of gold nanoparticles, the best way to get optimal gold nanoparticles is to control the reaction conditions via online chemiluminescence sensing systems. Therefore, a new method was developed for online synthesis of gold nanoparticles with a three-dimension hydrodynamic focusing microreactor, directly coupled with a microfluidic chemiluminescence sensing chip, which was coupled to a charge-coupled device camera for direct catalytical characterization of gold nanoparticles. All operations were performed in an automatic way with a program controlled by Matlab. Gold nanoparticles were synthesized through a single-phase reaction using glucose as a reducing agent and stabilizer at room temperature. The property of gold nanoparticles was easily controlled with the three-dimension microreactor during synthesis. The catalyst property of synthesized gold nanoparticles was characterized in a luminol-NaOCl chemiluminescence system. After optimizing parameters of synthesis, the chemiluminescence signal was enhanced to a factor of 171. The gold nanoparticles synthesized under optimal conditions for the luminol-NaOCl system were stable for at least one month. To further investigate the catalytic activity of synthesized gold nanoparticles in various situations, two methods were used to change the property of gold nanoparticles. After adding a certain amount of salt (NaCl), gold nanoparticles aggregated with a changed surface charge property and the catalytic activity was greatly enhanced. Glutathione was used as an example of molecules with thiol groups which interact with gold nanoparticles and reduce the catalytic activity. The chemiluminescence intensity was reduced by 98.9%. Therefore, we could show that using a microreactor for gold nanoparticles synthesis and direct coupling with microfluidic chemiluminescence sensing offers a promising monitoring method to find the best synthesis condition of gold nanoparticles for catalytic activity.
Collapse
Affiliation(s)
| | - Michael Seidel
- Correspondence: ; Tel.: +49-89-2180-78252; Fax: +49-89-2180-78255
| |
Collapse
|
7
|
Huang SP, Chuang YJ, Lee WB, Tsai YC, Lin CN, Hsu KF, Lee GB. An integrated microfluidic system for rapid, automatic and high-throughput staining of clinical tissue samples for diagnosis of ovarian cancer. LAB ON A CHIP 2020; 20:1103-1109. [PMID: 32040102 DOI: 10.1039/c9lc00979e] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Accurate cancer diagnostic methods are of urgent need. Since traditional immunohistochemistry (IHC)-based approaches, while reliable, are labor-intensive and require well-trained technicians, we developed an integrated microfluidic platform capable of labeling ovarian cancer biomarkers (i.e. aptamer) within formalin-fixed, paraffin embedded tissues via molecular probes. Both aptamer-based 1) fluorescent staining and 2) IHC staining of clinical tissue samples could be automated in the microfluidic system in only 2-3 h (40-50% faster than conventional approaches) with <0.5 mL of reagents, signifying that this device could serve as a promising diagnostic tool for ovarian cancer.
Collapse
Affiliation(s)
- Sheng-Po Huang
- Institute of NanoEngineering and MicroSystems, National Tsing Hua University, Hsinchu, Taiwan
| | - Yuan-Jhe Chuang
- Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, 70403 Taiwan.
| | - Wen-Bin Lee
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
| | - Yi-Cheng Tsai
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
| | - Chang-Ni Lin
- Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, 70403 Taiwan.
| | - Keng-Fu Hsu
- Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, 70403 Taiwan.
| | - Gwo-Bin Lee
- Institute of NanoEngineering and MicroSystems, National Tsing Hua University, Hsinchu, Taiwan and Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan. and Institute of Biomedical Engineering, National Tsing Hua University, Hsinchu, Taiwan
| |
Collapse
|
8
|
Chiu CH, Tong YW, Yeh WL, Lei KF, Chen ACY. Self-Renewal and Differentiation of Adipose-Derived Stem Cells (ADSCs) Stimulated by Multi-Axial Tensile Strain in a Pneumatic Microdevice. MICROMACHINES 2018; 9:E607. [PMID: 30463251 PMCID: PMC6267491 DOI: 10.3390/mi9110607] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/15/2018] [Accepted: 11/15/2018] [Indexed: 02/06/2023]
Abstract
Adipose-derived stem cells (ADSCs) were suggested for treating degenerative osteoarthritis, suppressing inflammatory responses, and repairing damaged soft tissues. Moreover, the ADSCs have the potential to undergo self-renewal and differentiate into bone, tendon, cartilage, and ligament. Recently, investigation of the self-renewal and differentiation of the ADSCs has become an attractive area. In this work, a pneumatic microdevice has been developed to study the gene expression of the ADSCs after the stimulation of multi-axial tensile strain. The ADSCs were cultured on the microdevice and experienced multi-axial tensile strain during a three-day culture course. Self-renewal and differentiation abilities were investigated by mRNA expressions of NANOG, sex determining region Y-box 2 (SOX2), octamer-binding transcription factor 4 (OCT4), sex determining region Y-box9 (SOX9), peroxisome proliferator-activated receptor gamma (PPAR-γ), and runt-related transcription factor 2 (RUNX2). The result showed that the genes related self-renewal were significantly up-regulated after the tensile stimulation. Higher proliferation ratio of the ADSCs was also shown by cell viability assay. The microdevice provides a promising platform for cell-based study under mechanical tensile stimulation.
Collapse
Affiliation(s)
- Chih-Hao Chiu
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan.
- Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou 333, Taiwan.
| | - Yun-Wen Tong
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan.
| | - Wen-Ling Yeh
- Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou 333, Taiwan.
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Linkou 333, Taiwan.
| | - Kin Fong Lei
- Graduate Institute of Biomedical Engineering, Chang Gung University, Taoyuan 333, Taiwan.
- Department of Radiation Oncology, Chang Gung Memorial Hospital, Linkou 333, Taiwan.
| | - Alvin Chao-Yu Chen
- Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou 333, Taiwan.
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Linkou 333, Taiwan.
| |
Collapse
|
9
|
Shirai A, Nakashima K, Sueyoshi K, Endo T, Hisamoto H. Development of a single-step immunoassay microdevice based on a graphene oxide-containing hydrogel possessing fluorescence quenching and size separation functions. Analyst 2018; 142:472-477. [PMID: 28091627 DOI: 10.1039/c6an02485h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An immunoassay, which is an indispensable analytical method both in biological research and in medical fields was successfully integrated into a "single-step" by developing a microdevice composed of a graphene oxide (GO)-containing hydrogel and a poly (dimethylsiloxane) (PDMS) microchannel array with a polyethylene glycol (PEG) coating containing a fluorescently-labelled antibody. Here we used 2-hydroxyethylmethacrylate (HEMA) as a monomer that is easily, and homogeneously, mixed with GO to synthesize the hydrogel. The fluorescence quenching and size separation functions were then optimized by controlling the ratios of HEMA and GO. Free fluorescently-labelled antibody was successfully separated from the immunoreaction mixture by the hydrogel network structure, and the fluorescence was subsequently quenched by GO. In comparison to the previously reported immunoassay system using GO, the present system achieved a very high fluorescence resonance energy transfer (FRET) efficiency (∼90%), due to the use of direct adsorption of the fluorescently-labelled antibody to the GO surface; in contrast, the former reported method relied on indirect adsorption of the fluorescently-labelled antibody via immunocomplex formation at the GO surface. Finally, the single-step immunoassay microdevice was made by combining the developed hydrogel and the PDMS microchannel with a coating containing the fluorescently-labelled antibody, and successfully applied for the single-step analysis of IgM levels in diluted human serum by simple introduction of the sample via capillary action.
Collapse
Affiliation(s)
- Akihiro Shirai
- Graduate School of Engineering, Osaka Prefecture University, 1-1, Gakuen-cho Nakaku, Sakai City, Osaka, 599-8531, Japan.
| | - Kaho Nakashima
- Graduate School of Engineering, Osaka Prefecture University, 1-1, Gakuen-cho Nakaku, Sakai City, Osaka, 599-8531, Japan.
| | - Kenji Sueyoshi
- Graduate School of Engineering, Osaka Prefecture University, 1-1, Gakuen-cho Nakaku, Sakai City, Osaka, 599-8531, Japan.
| | - Tatsuro Endo
- Graduate School of Engineering, Osaka Prefecture University, 1-1, Gakuen-cho Nakaku, Sakai City, Osaka, 599-8531, Japan.
| | - Hideaki Hisamoto
- Graduate School of Engineering, Osaka Prefecture University, 1-1, Gakuen-cho Nakaku, Sakai City, Osaka, 599-8531, Japan.
| |
Collapse
|
10
|
Tu YK, Tsai MZ, Lee IC, Hsu HY, Huang CS. Integration of a guided-mode resonance filter with microposts for in-cell protein detection. Analyst 2018; 141:4189-95. [PMID: 27170945 DOI: 10.1039/c6an00023a] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present an integrated microfluidic system consisting of a label-free biosensor of a guided-mode resonance filter (GMRF) and a microfluidic channel with a micropost filter. The GMRF was fabricated through replica molding using an ultraviolet-curable polymer and a plastic substrate. An array of microposts (a diameter and height of 26.5 and 56 μm, respectively, and a spacing between 7.5 and 9.5 μm), fabricated on a silicon substrate through photolithography, was used as the filter. A double-sided tape was used to laminate the GMRF and a microfluidic chip such that the integrated device provides two functions: filtration of the cell debris and quantification of the in-cell protein concentration. By measuring the changes in the resonant wavelength from the GMRF, the detection of β-actin in an unprocessed lysed cell sample was demonstrated; the cell debris was separated using the micropost filter to prevent false measurement.
Collapse
Affiliation(s)
- Yi-Kai Tu
- Department of Mechanical Engineering, National Chiao Tung University, 1001 Ta Hsueh Rd., Hsinchu, Taiwan 30010.
| | - Meng-Zhe Tsai
- Department of Mechanical Engineering, National Chiao Tung University, 1001 Ta Hsueh Rd., Hsinchu, Taiwan 30010.
| | - I-Chin Lee
- Department of Applied Chemistry, National Chiao Tung University, 1001 Ta Hsueh Rd., Hsinchu, Taiwan 30010
| | - Hsin-Yun Hsu
- Department of Applied Chemistry, National Chiao Tung University, 1001 Ta Hsueh Rd., Hsinchu, Taiwan 30010
| | - Cheng-Sheng Huang
- Department of Mechanical Engineering, National Chiao Tung University, 1001 Ta Hsueh Rd., Hsinchu, Taiwan 30010.
| |
Collapse
|
11
|
Shirai A, Henares TG, Sueyoshi K, Endo T, Hisamoto H. Fast and single-step immunoassay based on fluorescence quenching within a square glass capillary immobilizing graphene oxide-antibody conjugate and fluorescently labelled antibody. Analyst 2018; 141:3389-94. [PMID: 27127806 DOI: 10.1039/c5an02637g] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A single-step, easy-to-use, and fast capillary-type immunoassay device composed of a polyethylene glycol (PEG) coating containing two kinds of antibody-reagents, including an antibody-graphene oxide conjugate and fluorescently labelled antibody, was developed in this study. The working principle involved the spontaneous dissolution of the PEG coating, diffusion of reagents, and subsequent immunoreaction, triggered by the capillary action-mediated introduction of a sample solution. In a sample solution containing the target antigen, two types of antibody reagents form a sandwich-type antigen-antibody complex and fluorescence quenching takes place via fluorescence resonance energy transfer between the labelled fluorescent molecules and graphene oxide. Antigen concentration can be measured based on the decrease in fluorescence intensity. An antigen concentration-dependent response was obtained for the model target protein sample (human IgG, 0.2-10 μg mL(-1)). The present method can shorten the reaction time to within 1 min (approximately 40 s), while conventional methods using the same reagents require reaction times of approximately 20 min because of the large reaction scale. The proposed method is one of the fastest immunoassays ever reported. Finally, the present device was used to measure human IgG in diluted serum samples to demonstrate that this method can be used for fast medical diagnosis.
Collapse
Affiliation(s)
- Akihiro Shirai
- Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho Nakaku, Sakai City, Osaka 599-8531, Japan.
| | - Terence G Henares
- Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho Nakaku, Sakai City, Osaka 599-8531, Japan.
| | - Kenji Sueyoshi
- Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho Nakaku, Sakai City, Osaka 599-8531, Japan.
| | - Tatsuro Endo
- Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho Nakaku, Sakai City, Osaka 599-8531, Japan.
| | - Hideaki Hisamoto
- Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho Nakaku, Sakai City, Osaka 599-8531, Japan.
| |
Collapse
|
12
|
Optimization of Micropump Performance Utilizing a Single Membrane with an Active Check Valve. MICROMACHINES 2017; 9:mi9010001. [PMID: 30393278 PMCID: PMC6187502 DOI: 10.3390/mi9010001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 12/11/2017] [Accepted: 12/18/2017] [Indexed: 11/17/2022]
Abstract
In this study, we successfully designed and tested a new micropump that utilizes an active check valve and bottom-protruding structure to achieve sample transportation. We performed theoretical analyses and numerical simulations to determine the optimal location of the active check valve. We also experimentally analyzed variations in the generated flow rate with respect to the pneumatic frequencies, actuated air pressures, and locations of the active check valve. The experimental results indicate the optimum air pressure, driving frequency, and location of the active check valve to be 68.9 kPa, 26.0 Hz, and 2.0 mm, respectively. We obtained a maximum pumping rate of 488 μL/min and a maximum pumping efficiency of 35.4%. The proposed micropump could perform a crucial function in the transportation of microfluids and could be incorporated into micro total analysis systems.
Collapse
|
13
|
|
14
|
Fei J, Wu L, Zhang Y, Zong S, Wang Z, Cui Y. Pharmacokinetics-on-a-Chip Using Label-Free SERS Technique for Programmable Dual-Drug Analysis. ACS Sens 2017; 2:773-780. [PMID: 28723125 DOI: 10.1021/acssensors.7b00122] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Synergistic effects of dual or multiple drugs have attracted great attention in medical fields, especially in cancer therapies. We provide a programmable microfluidic platform for pharmacokinetic detection of multiple drugs in multiple cells. The well-designed microfluidic platform includes two 2 × 3 microarrays of cell chambers, two gradient generators, and several pneumatic valves. Through the combined use of valves and gradient generators, each chamber can be controlled to infuse different kinds of living cells and drugs with specific concentrations as needed. In our experiments, 6-mercaptopurine (6MP) and methimazole (MMI) were chosen as two drug models and their pharmacokinetic parameters in different living cells were monitored through intracellular SERS spectra, which reflected the molecular structure of these drugs. The dynamic change of SERS fingerprints from 6MP and MMI molecules were recorded during drug metabolism in living cells. The results indicated that both 6MP and MMI molecules were diffused into the cells within 4 min and excreted out after 36 h. Moreover, the intracellular distribution of these drugs was monitored through SERS mapping. Thus, our microfluidic platform simultaneously accomplishes the functions to monitor pharmacokinetic action, distribution, and fingerprint of multiple drugs in multiple cells. Owing to its real-time, rapid-speed, high-precision, and programmable capability of multiple-drug and multicell analysis, such a microfluidic platform has great potential in drug design and development.
Collapse
Affiliation(s)
- Jiayuan Fei
- Advanced Photonics Center, Southeast University, Nanjing, 210096, China
| | - Lei Wu
- Advanced Photonics Center, Southeast University, Nanjing, 210096, China
| | - Yizhi Zhang
- Advanced Photonics Center, Southeast University, Nanjing, 210096, China
| | - Shenfei Zong
- Advanced Photonics Center, Southeast University, Nanjing, 210096, China
| | - Zhuyuan Wang
- Advanced Photonics Center, Southeast University, Nanjing, 210096, China
| | - Yiping Cui
- Advanced Photonics Center, Southeast University, Nanjing, 210096, China
| |
Collapse
|
15
|
Polovnikov KE, Gumerov RA, Potemkin II. Stress-Induced Solvent Redistribution in Lamellae-Forming Diblock Copolymer Systems. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kirill E. Polovnikov
- Physics
Department, Lomonosov Moscow State University, Moscow 119991, Russian Federation
| | - Rustam A. Gumerov
- Physics
Department, Lomonosov Moscow State University, Moscow 119991, Russian Federation
| | - Igor I. Potemkin
- Physics
Department, Lomonosov Moscow State University, Moscow 119991, Russian Federation
| |
Collapse
|
16
|
Zhou W, Niu L, Cai F, Li F, Wang C, Huang X, Wang J, Wu J, Meng L, Zheng H. Spatial selective manipulation of microbubbles by tunable surface acoustic waves. BIOMICROFLUIDICS 2016; 10:034121. [PMID: 27462381 PMCID: PMC4930446 DOI: 10.1063/1.4954934] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Accepted: 06/15/2016] [Indexed: 05/05/2023]
Abstract
A microfluidic device based on a pair of slant-finger interdigital transducers (SFITs) is developed to achieve a selective and flexible manipulation of microbubbles (MBs) by surface acoustic waves (SAWs). The resonance frequency of SAWs generated by the SFITs depends on the location of its parallel pathway; the particles at different locations of the SAWs' pathway can be controlled selectively by choosing the frequency of the excitation signal applied on the SFITs. By adjusting the input signal continuously, MBs can be transported along the acoustic aperture precisely. The displacement of MBs has a linear relationship with the frequency shift. The resolution of transportation is 15.19 ± 2.65 μm when the shift of input signal frequency is at a step of 10 kHz. In addition, the MBs can be controlled in a two-dimensional plane by combining variations of the frequency and the relative phase of the excitation signal applied on the SFITs simultaneously. This technology may open up the possibility of selectively and flexibly manipulating MBs using a simple one-dimensional device.
Collapse
Affiliation(s)
- Wei Zhou
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences , Shenzhen 518055, People's Republic of China
| | - Lili Niu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences , Shenzhen 518055, People's Republic of China
| | - Feiyan Cai
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences , Shenzhen 518055, People's Republic of China
| | - Fei Li
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences , Shenzhen 518055, People's Republic of China
| | - Chen Wang
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences , Shenzhen 518055, People's Republic of China
| | - Xiaowei Huang
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences , Shenzhen 518055, People's Republic of China
| | - Jingjing Wang
- Research Center for Micro/Nano Systems and Bionic Medicine, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology , Chinese Academy of Sciences, Shenzhen 518055, People's Republic of China
| | - Junru Wu
- Department of Physics, University of Vermont , Burlington, Vermont 05405 USA
| | - Long Meng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences , Shenzhen 518055, People's Republic of China
| | - Hairong Zheng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences , Shenzhen 518055, People's Republic of China
| |
Collapse
|
17
|
|
18
|
Wang CH, Weng CH, Che YJ, Wang K, Lee GB. Cancer cell-specific oligopeptides selected by an integrated microfluidic system from a phage display library for ovarian cancer diagnosis. Theranostics 2015; 5:431-42. [PMID: 25699101 PMCID: PMC4329505 DOI: 10.7150/thno.10891] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/07/2015] [Indexed: 12/03/2022] Open
Abstract
Ovarian cancer is one of the leading causes of female mortality worldwide. Unfortunately, there are currently few high-specificity candidate oligopeptide targeting agents that can be used for early diagnosis of this cancer. It has been suggested that cancer-specific oligopeptides could be screened from a phage display library. However, conventional methods are tedious, labor-intensive, and time consuming. Therefore, a novel, integrated microfluidic system was developed to automate the entire screening process for ovarian cancer cell-specific oligopeptides. An oligopeptide screened with microfluidic chip-based technique was demonstrated to have high affinity to ovarian cancer cells and demonstrated relatively low binding to other cancer cells, indicating a high specificity. Furthermore, the developed method consumed relatively low volumes of samples and reagents; only 70 μL of reactant was used within the whole experimental process. Each panning process was also significantly shortened to only 7.5 hours. Therefore, the screened oligopeptide could be used to isolate ovarian cancer cells in a rapid manner, thus greatly expediting the diagnosis and its application as oligopeptide targeting agent for theranostics of this cancer.
Collapse
|
19
|
Deformation Analysis of a Pneumatically-Activated Polydimethylsiloxane (PDMS) Membrane and Potential Micro-Pump Applications. MICROMACHINES 2015. [DOI: 10.3390/mi6020216] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
20
|
Hu SW, Xu BY, Ye WK, Xia XH, Chen HY, Xu JJ. Versatile microfluidic droplets array for bioanalysis. ACS APPLIED MATERIALS & INTERFACES 2015; 7:935-940. [PMID: 25525675 DOI: 10.1021/am5075216] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We propose a novel method to obtain versatile droplets arrays on a regional hydrophilic chip that is fabricated by PDMS soft lithography and regional plasma treatment. It enables rapid liquid dispensation and droplets array formation just making the chip surface in contact with solution. By combining this chip with a special Christmas Tree structure, the droplets array with concentrations in gradient is generated. It possesses the greatly improved performance of convenience and versatility in bioscreening and biosensing. For example, high throughput condition screening of toxic tests of CdSe quantum dots on HL-60 cells are conducted and cell death rates are successfully counted quickly and efficiently. Furthermore, a rapid biosensing approach for cancer biomarkers carcinoma embryonic antigen (CEA) is developed via magnetic beads (MBs)-based sandwich immunoassay methods.
Collapse
Affiliation(s)
- Shan-Wen Hu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, P.R. China
| | | | | | | | | | | |
Collapse
|
21
|
Microfluidic platform towards point-of-care diagnostics in infectious diseases. J Chromatogr A 2014; 1377:13-26. [PMID: 25544727 DOI: 10.1016/j.chroma.2014.12.041] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 12/06/2014] [Accepted: 12/09/2014] [Indexed: 01/09/2023]
Abstract
Rapid and timely diagnosis of infectious diseases is a critical determinant of clinical outcomes and general public health. For the detection of various pathogens, microfluidics-based platforms offer many advantages, including speed, cost, portability, high throughput, and automation. This review provides an overview of the recent advances in microfluidic technologies for point-of-care (POC) diagnostics for infectious diseases. The key aspects of such technologies for the development of a fully integrated POC platform are introduced, including sample preparation, on-chip nucleic acid analysis and immunoassay, and system integration/automation. The current challenges to practical implementation of this technology are discussed together with future perspectives.
Collapse
|
22
|
Yi P, Awang RA, Rowe WST, Kalantar-zadeh K, Khoshmanesh K. PDMS nanocomposites for heat transfer enhancement in microfluidic platforms. LAB ON A CHIP 2014; 14:3419-26. [PMID: 25007921 DOI: 10.1039/c4lc00615a] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Increasing the thermal conductivity of PDMS (polydimethylsiloxane) based microfluidics is an important issue for the thermal management of hot spots produced by embedding electronic circuits in such systems. This paper presents a solution for enhancing the thermal conductivity of such PDMS based microfluidics by introducing thermally conductive alumina (Al2O3) nanoparticles, forming PDMS/Al2O3 nanocomposites. The materials are fully characterized for different concentrations of Al2O3 in PDMS for experiments which are conducted at different flow rates. Our results suggest that incorporation of Al2O3 nanoparticles at 10% w/w in the PDMS based nanocomposite significantly enhances the heat conduction from hot spots by enhancing the thermal conductivity, while maintaining the flexibility and decreasing the specific heat capacity of the developed materials. This proof-of-concept study offers potential for a practical solution for the cooling of future embedded electronic systems.
Collapse
Affiliation(s)
- Pyshar Yi
- RMIT University, School of Electrical and Computer Engineering, Melbourne, Victoria 3001, Australia.
| | | | | | | | | |
Collapse
|
23
|
Jing W, Jiang X, Zhao W, Liu S, Cheng X, Sui G. Microfluidic Platform for Direct Capture and Analysis of Airborne Mycobacterium tuberculosis. Anal Chem 2014; 86:5815-21. [DOI: 10.1021/ac500578h] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Wenwen Jing
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science & Engineering, Fudan University, 220 Handan Road, Shanghai, 200433, P.R. China
- Department
of Medical Microbiology and Parasitology, School of Basic Medical
Sciences, Fudan University, Shanghai, 200032, P.R. China
| | - Xiran Jiang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science & Engineering, Fudan University, 220 Handan Road, Shanghai, 200433, P.R. China
| | - Wang Zhao
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science & Engineering, Fudan University, 220 Handan Road, Shanghai, 200433, P.R. China
| | - Sixiu Liu
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science & Engineering, Fudan University, 220 Handan Road, Shanghai, 200433, P.R. China
| | - Xunjia Cheng
- Department
of Medical Microbiology and Parasitology, School of Basic Medical
Sciences, Fudan University, Shanghai, 200032, P.R. China
- Institute
of Biomedical Science, Fudan University, Shanghai, 200433, P.R. China
| | - Guodong Sui
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science & Engineering, Fudan University, 220 Handan Road, Shanghai, 200433, P.R. China
- Institute
of Biomedical Science, Fudan University, Shanghai, 200433, P.R. China
| |
Collapse
|
24
|
Protein binding reaction enhanced by bi-directional flow driven by on-chip thermopneumatic actuator. Biomed Microdevices 2014; 16:325-32. [DOI: 10.1007/s10544-014-9835-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
25
|
A micro blood sampling system for catheterized neonates and pediatrics in intensive care unit. Biomed Microdevices 2013; 15:241-53. [PMID: 23150205 DOI: 10.1007/s10544-012-9724-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A new micro blood sampling system has been designed, fabricated, and characterized to reduce iatrogenic blood loss from the catheterized neonates and pediatrics in intensive care unit by providing micro-volume of blood to analytical biomedical microdevices which can do point-of-care testing for their critical care. The system can not only save enormous iatrogenic blood loss through 1 to 10 μL of blood sampling and re-infusion of 1 to 5 mL of discard blood but also reduce the infection risk through the closed structure while satisfying the key criteria of the blood sampler. The sampled blood preserved its quality without rupturing of red blood cells verified by blood potassium concentrations of 3.86 ± 0.07 mM on the sampled blood which is similar to 3.81 ± 0.04 mM measured from the blood which did not go through the system. The sampling volume among the sampling channels showed consistency with the relative standard deviation of 1.41 %. In addition to the micro blood sampling capability, the sampling system showed negligible sample cross-contamination. The analyte-free samples collected after aspirating 7,500 times higher signal sample showed the same output signal as blank. The system was also demonstrated not to cause air-embolism by having no bubble generation during flushing procedure and the system was verified as leak-free since there was no fluid leakage under 30 times higher pressure than central venous pressure for 24 h.
Collapse
|
26
|
Valtiner M, Banquy X, Kristiansen K, Greene GW, Israelachvili JN. The electrochemical surface forces apparatus: the effect of surface roughness, electrostatic surface potentials, and anodic oxide growth on interaction forces, and friction between dissimilar surfaces in aqueous solutions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:13080-13093. [PMID: 22877582 DOI: 10.1021/la3018216] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present a newly designed electrochemical surface forces apparatus (EC-SFA) that allows control and measurement of surface potentials and interfacial electrochemical reactions with simultaneous measurement of normal interaction forces (with nN resolution), friction forces (with μN resolution), and distances (with Å resolution) between apposing surfaces. We describe three applications of the developed EC-SFA and discuss the wide-range of potential other applications. In particular, we describe measurements of (1) force-distance profiles between smooth and rough gold surfaces and apposing self-assembled monolayer-covered smooth mica surfaces; (2) the effective changing thickness of anodically growing oxide layers with Å-accuracy on rough and smooth surfaces; and (3) friction forces evolving at a metal-ceramic contact, all as a function of the applied electrochemical potential. Interaction forces between atomically smooth surfaces are well-described using DLVO theory and the Hogg-Healy-Fuerstenau approximation for electric double layer interactions between dissimilar surfaces, which unintuitively predicts the possibility of attractive double layer forces between dissimilar surfaces whose surface potentials have similar sign, and repulsive forces between surfaces whose surface potentials have opposite sign. Surface roughness of the gold electrodes leads to an additional exponentially repulsive force in the force-distance profiles that is qualitatively well described by an extended DLVO model that includes repulsive hydration and steric forces. Comparing the measured thickness of the anodic gold oxide layer and the charge consumed for generating this layer allowed the identification of its chemical structure as a hydrated Au(OH)(3) phase formed at the gold surface at high positive potentials. The EC-SFA allows, for the first time, one to look at complex long-term transient effects of dynamic processes (e.g., relaxation times), which are also reflected in friction forces while tuning electrochemical surface potentials.
Collapse
Affiliation(s)
- Markus Valtiner
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United States
| | | | | | | | | |
Collapse
|
27
|
Abstract
Because of intensive developments in recent years, the microfluidic system has become a powerful tool for biological analysis. Entire analytic protocols including sample pretreatment, sample/reagent manipulation, separation, reaction, and detection can be integrated into a single chip platform. A lot of demonstrations on the diagnostic applications related to genes, proteins, and cells have been reported because of their advantages associated with miniaturization, automation, sensitivity, and specificity. The aim of this article is to review recent developments in microfluidic systems for diagnostic applications. Based on the categories of various fluid-manipulating mechanisms and biological detection approaches, in-depth discussion of the microfluidic-based diagnostic systems is provided. Moreover, a brief discussion on materials and manufacturing techniques will be included. The current excellent integration of microfluidic systems and diagnostic applications suggests a solid foundation for the development of practical point-of-care devices.
Collapse
|
28
|
Balasuriya S, Finn MD. Energy constrained transport maximization across a fluid interface. PHYSICAL REVIEW LETTERS 2012; 108:244503. [PMID: 23004278 DOI: 10.1103/physrevlett.108.244503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Indexed: 06/01/2023]
Abstract
With enhancing mixing in micro- or nanofluidic applications in mind, the problem of maximizing fluid transport across a fluid interface subject to an available energy budget is examined. The optimum cross-interface perturbing velocity is obtained explicitly in the time-periodic instance using an Euler-Lagrange constrained optimization approach. Numerical investigations which calculate transferred lobe areas and cross-interface flux are used to verify that the predicted strategy achieves optimum transport. Explicit active protocols for achieving this optimal transport are suggested.
Collapse
Affiliation(s)
- Sanjeeva Balasuriya
- Department of Mathematics, Connecticut College, New London, Connecticut 06320, USA.
| | | |
Collapse
|
29
|
Cao Q, Mahalanabis M, Chang J, Carey B, Hsieh C, Stanley A, Odell CA, Mitchell P, Feldman J, Pollock NR, Klapperich CM. Microfluidic chip for molecular amplification of influenza A RNA in human respiratory specimens. PLoS One 2012; 7:e33176. [PMID: 22457740 PMCID: PMC3310856 DOI: 10.1371/journal.pone.0033176] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 02/05/2012] [Indexed: 11/18/2022] Open
Abstract
A rapid, low cost, accurate point-of-care (POC) device to detect influenza virus is needed for effective treatment and control of both seasonal and pandemic strains. We developed a single-use microfluidic chip that integrates solid phase extraction (SPE) and molecular amplification via a reverse transcription polymerase chain reaction (RT-PCR) to amplify influenza virus type A RNA. We demonstrated the ability of the chip to amplify influenza A RNA in human nasopharyngeal aspirate (NPA) and nasopharyngeal swab (NPS) specimens collected at two clinical sites from 2008-2010. The microfluidic test was dramatically more sensitive than two currently used rapid immunoassays and had high specificity that was essentially equivalent to the rapid assays and direct fluorescent antigen (DFA) testing. We report 96% (CI 89%,99%) sensitivity and 100% (CI 95%,100%) specificity compared to conventional (bench top) RT-PCR based on the testing of n = 146 specimens (positive predictive value = 100%(CI 94%,100%) and negative predictive value = 96%(CI 88%,98%)). These results compare well with DFA performed on samples taken during the same time period (98% (CI 91%,100%) sensitivity and 96%(CI 86%,99%) specificity compared to our gold standard testing). Rapid immunoassay tests on samples taken during the enrollment period were less reliable (49%(CI 38%,61%) sensitivity and 98%(CI 98%,100%) specificity). The microfluidic test extracted and amplified influenza A RNA directly from clinical specimens with viral loads down to 10³ copies/ml in 3 h or less. The new test represents a major improvement over viral culture in terms of turn around time, over rapid immunoassay tests in terms of sensitivity, and over bench top RT-PCR and DFA in terms of ease of use and portability.
Collapse
Affiliation(s)
- Qingqing Cao
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Madhumita Mahalanabis
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Jessie Chang
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Brendan Carey
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Christopher Hsieh
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Ahjegannie Stanley
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Christine A. Odell
- Department of Pediatrics, Division of Pediatric Emergency Medicine, Boston Medical Center and Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Patricia Mitchell
- Department of Emergency Medicine, Boston Medical Center and Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - James Feldman
- Department of Emergency Medicine, Boston Medical Center and Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Nira R. Pollock
- Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Catherine M. Klapperich
- Department of Mechanical Engineering, Boston University, Boston, Massachusetts, United States of America
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
30
|
Kim J, Kang M, Jensen EC, Mathies RA. Lifting gate polydimethylsiloxane microvalves and pumps for microfluidic control. Anal Chem 2012; 84:2067-71. [PMID: 22257104 DOI: 10.1021/ac202934x] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We describe the development and characterization of pneumatically actuated "lifting gate" microvalves and pumps. A fluidic layer containing the gate structure and a pneumatic layer are fabricated by soft-lithography in PDMS and bonded permanently with an oxygen plasma treatment. The microvalve structures are then reversibly bonded to a featureless glass or plastic substrate to form hybrid glass-PDMS and plastic-PDMS microchannel structures. The break-through pressures of the microvalve increase linearly up to 65 kPa as the closing pressure increases. The pumping capability of these structures ranges from the nanoliter to microliter scale depending on the number of cycles and closing pressure employed. The micropump structures exhibit up to 86.2% pumping efficiency from flow rate measurements. The utility of these structures for integrated sample processing is demonstrated by performing an automated immunoassay. These lifting gate valve and pump structures enable facile integration of complex microfluidic control systems with a wide range of lab-on-a-chip substrates.
Collapse
Affiliation(s)
- Jungkyu Kim
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | | | | | | |
Collapse
|
31
|
Rapp BE, Schickling B, Prokop J, Piotter V, Rapp M, Länge K. Design and integration of a generic disposable array-compatible sensor housing into an integrated disposable indirect microfluidic flow injection analysis system. Biomed Microdevices 2011; 13:909-22. [DOI: 10.1007/s10544-011-9560-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
32
|
Noroozi Z, Kido H, Peytavi R, Nakajima-Sasaki R, Jasinskas A, Micic M, Felgner PL, Madou MJ. A multiplexed immunoassay system based upon reciprocating centrifugal microfluidics. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:064303. [PMID: 21721711 PMCID: PMC3188650 DOI: 10.1063/1.3597578] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
A novel, centrifugal disk-based micro-total analysis system (μTAS) for low cost and high throughput semi-automated immunoassay processing was developed. A key innovation in the disposable immunoassay disk design is in a fluidic structure that enables very efficient micro-mixing based on a reciprocating mechanism in which centrifugal acceleration acting upon a liquid element first generates and stores pneumatic energy that is then released by a reduction of the centrifugal acceleration, resulting in a reversal of direction of flow of the liquid. Through an alternating sequence of high and low centrifugal acceleration, the system reciprocates the flow of liquid within the disk to maximize incubation/hybridization efficiency between antibodies and antigen macromolecules during the incubation/hybridization stage of the assay. The described reciprocating mechanism results in a reduction in processing time and reagent consumption by one order of magnitude.
Collapse
Affiliation(s)
- Zahra Noroozi
- Department of Mechanical and Aerospace Engineering, University of California, Irvine, 4200 Engineering Gateway, Irvine, California 92697-3975, USA
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Valtiner M, Kristiansen K, Greene GW, Israelachvili JN. Effect of surface roughness and electrostatic surface potentials on forces between dissimilar surfaces in aqueous solution. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:2294-2299. [PMID: 21608041 DOI: 10.1002/adma.201003709] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 11/23/2010] [Indexed: 05/30/2023]
Affiliation(s)
- Markus Valtiner
- Department of Chemical Engineering, University of California-Santa Barbara, Santa Barbara, CA 93106-5080, USA
| | | | | | | |
Collapse
|
34
|
Browne AW, Ahn CH. An in-line microfluidic blood sampling interface between patients and saline infusion systems. Biomed Microdevices 2011; 13:661-9. [DOI: 10.1007/s10544-011-9536-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
|
35
|
Wang W, Huang Y, Liu J, Xie Y, Zhao R, Xiong S, Liu G, Chen Y, Ma H. Integrated SPPS on continuous-flow radial microfluidic chip. LAB ON A CHIP 2011; 11:929-935. [PMID: 21270975 DOI: 10.1039/c0lc00542h] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A novel integrated continuous-flow microfluidic system was designed and fabricated for solid phase peptide synthesis (SPPS) using conventional reactants. The microfluidic system was composed of a glass-based radial reaction chip, a diffluent chip, amino acid feeding reservoirs and continuous-flow reagent pathways. A tri-row cofferdam-fence structure was designed for solid phase supports trapping. Highly cross-linked, porous and high-loading 4-(hydroxymethyl)phenoxymethyl polystyrene (HMP) beads were prepared for microfluidic SPPS. The transfer losses, hazardous handling and time-consuming processes in traditional peptide cleavage steps were avoided by being replaced with the on-chip cleavage treatment. Six peptides from an antibody affinity peptide library against β-endorphin with different lengths and sequences were obtained simultaneously on the constructed continuous-flow microfluidic system within a short time. This microfluidic system is automatic, integrated, effective, low-cost, recyclable and environment-friendly for not only SPPS but also other solid phase chemical syntheses.
Collapse
Affiliation(s)
- Weizhi Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun North First Street 2, 100190 Beijing, PR China
| | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Panini NV, Salinas E, Messina GA, Raba J. Modified paramagnetic beads in a microfluidic system for the determination of zearalenone in feedstuffs samples. Food Chem 2011. [DOI: 10.1016/j.foodchem.2010.09.035] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
37
|
Microfluidic cell culture chip with multiplexed medium delivery and efficient cell/scaffold loading mechanisms for high-throughput perfusion 3-dimensional cell culture-based assays. Biomed Microdevices 2011; 13:415-30. [DOI: 10.1007/s10544-011-9510-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
38
|
Wang C, Trau D. A portable generic DNA bioassay system based on in situ oligonucleotide synthesis and hybridization detection. Biosens Bioelectron 2010; 26:2436-41. [PMID: 21094597 DOI: 10.1016/j.bios.2010.10.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 10/05/2010] [Accepted: 10/17/2010] [Indexed: 11/28/2022]
Abstract
In this study, we present a portable and generic DNA bioassay system based on in situ oligonucleotide synthesis followed by hybridization based detection. The system include two main parts, an oligonucleotide synthesizer and a fluorescence detection system. The oligonucleotide synthesizer is based on microfluidic technology and capable of synthesizing any desired oligonucleotide which can be either used as a primer for PCR based detection (external) or a probe for hybridization based detection (integrated) of a target DNA analyte. The oligonucleotide sequence can be remotely sent to the system. The integrated fluorescence detection system is based on a photodiode to detect Texas Red fluorophore as low as 0.5 fmol. The complete system, integrating the oligonucleotide synthesizer and fluorescence detection system, was successfully used to distinguish DNA from two different bacteria strains. The presented generic portable instrument has the potential to detect any desired DNA target sequence in the field. Potential applications are for homeland security and fast responses to emerging bio-threats.
Collapse
Affiliation(s)
- Chen Wang
- Division of Bioengineering, National University of Singapore, Singapore
| | | |
Collapse
|
39
|
Takashima A, Kojima K, Suzuki H. Autonomous Microfluidic Control by Chemically Actuated Micropumps and Its Application to Chemical Analyses. Anal Chem 2010; 82:6870-6. [DOI: 10.1021/ac1009657] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Atsushi Takashima
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan
| | - Kenichi Kojima
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan
| | - Hiroaki Suzuki
- Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan
| |
Collapse
|
40
|
Biosensors with label-free detection designed for diagnostic applications. Anal Bioanal Chem 2010; 398:2403-12. [DOI: 10.1007/s00216-010-3906-2] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 06/07/2010] [Accepted: 06/07/2010] [Indexed: 01/15/2023]
|
41
|
Lin CC, Tseng CC, Huang CJ, Wang JH, Lee GB. An integrated microfluidic chip for non-immunological determination of urinary albumin. Biomed Microdevices 2010; 12:887-96. [DOI: 10.1007/s10544-010-9443-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
42
|
Huang SB, Wu MH, Lee GB. Microfluidic device utilizing pneumatic micro-vibrators to generate alginate microbeads for microencapsulation of cells. SENSORS AND ACTUATORS B: CHEMICAL 2010; 147:755-764. [DOI: 10.1016/j.snb.2010.04.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
|
43
|
Lien KY, Lee GB. Miniaturization of molecular biological techniques for gene assay. Analyst 2010; 135:1499-518. [PMID: 20390199 DOI: 10.1039/c000037j] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The rapid diagnosis of various diseases is a critical advantage of many emerging biomedical tools. Due to advances in preventive medicine, tools for the accurate analysis of genetic mutation and associated hereditary diseases have attracted significant interests in recent years. The entire diagnostic process usually involves two critical steps, namely, sample pre-treatment and genetic analysis. The sample pre-treatment processes such as extraction and purification of the target nucleic acids prior to genetic analysis are essential in molecular diagnostics. The genetic analysis process may require specialized apparatus for nucleic acid amplification, sequencing and detection. Traditionally, pre-treatment of clinical biological samples (e.g. the extraction of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA)) and the analysis of genetic polymorphisms associated with genetic diseases are typically a lengthy and costly process. These labor-intensive and time-consuming processes usually result in a high-cost per diagnosis and hinder their practical applications. Besides, the accuracy of the diagnosis may be affected owing to potential contamination from manual processing. Alternatively, due to significant advances in micro-electro-mechanical-systems (MEMS) and microfluidic technology, there are numerous miniature systems employed in biomedical applications, especially for the rapid diagnosis of genetic diseases. A number of advantages including automation, compactness, disposability, portability, lower cost, shorter diagnosis time, lower sample and reagent consumption, and lower power consumption can be realized by using these microfluidic-based platforms. As a result, microfluidic-based systems are becoming promising platforms for genetic analysis, molecular biology and for the rapid detection of genetic diseases. In this review paper, microfluidic-based platforms capable of identifying genetic sequences and diagnosis of genetic mutations are surveyed and reviewed. Some critical issues with the use of microfluidic-based systems for diagnosis of genetic diseases are also highlighted.
Collapse
Affiliation(s)
- Kang-Yi Lien
- Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, Tainan, 701, Taiwan
| | | |
Collapse
|
44
|
Hannig C, Dirschka M, Länge K, Neumaier S, Rapp B. Synthesis and application of photo curable perfluoropolyethers as new material for microfluidics. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.proeng.2010.09.246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
45
|
Huang SB, Wu MH, Lee GB. A tunable micro filter modulated by pneumatic pressure for cell separation. SENSORS AND ACTUATORS B: CHEMICAL 2009; 142:389-399. [DOI: 10.1016/j.snb.2009.07.046] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
|
46
|
Kuo CH, Wang JH, Lee GB. A microfabricated CE chip for DNA pre-concentration and separation utilizing a normally closed valve. Electrophoresis 2009; 30:3228-35. [DOI: 10.1002/elps.200900112] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|
47
|
Kong J, Jiang L, Su X, Qin J, Du Y, Lin B. Integrated microfluidic immunoassay for the rapid determination of clenbuterol. LAB ON A CHIP 2009; 9:1541-7. [PMID: 19458860 DOI: 10.1039/b818430e] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
An integrated microfluidic immunoassay system was established for high throughput analysis of clenbuterol. This system consisted of an integrated microchip and a linear confocal laser induced fluorescence (LIF) scanner. The microchip was composed of three layers: a fluidic channel layer, a PDMS membrane layer and a pneumatic control layer. The multi-layer chip was integrated with 36 pneumatic micro-valves and multiple micro-pumps to realize the flexible reagent delivery, facilitating the automatic assays with less consumption of samples and reduced analysis time. The homemade LIF scanner was able to simultaneously detect multi-channels and provide the potential capability of high throughput assays. The performance of the system was demonstrated by the determination of clenbuterol, one of the most widely used beta-agonists. Under the optimal conditions, the linear range and the limit of detection of clenbuterol were 0 approximately 5.0 ng mL(-1) and 0.088 ng mL(-1), respectively. The recovery rates determined with pig urine samples of 1.0 ng mL(-1) and 2.0 ng mL(-1) were 98.74% and 102.51% (n = 3), respectively. The total detection time was less than 30 min. The system had the potential application for rapid detection of multiple beta-agonists in clinical, pharmaceutical and chemical analyses.
Collapse
Affiliation(s)
- Jing Kong
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | | | | | | | | | | |
Collapse
|
48
|
Magnetic-bead-based microfluidic system for ribonucleic acid extraction and reverse transcription processes. Biomed Microdevices 2009; 11:339-50. [PMID: 19034667 DOI: 10.1007/s10544-008-9240-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
This paper presents a new integrated microfluidic chip that automatically performs ribonucleic acid (RNA) extraction and reverse transcription (RT) processes. The microfluidic system consists of a microfluidic control module and a magnetic bio-separator. The microfluidic control module can perform pumping and mixing of small amount of fluids and subsequent purification and concentration of RNA samples by incorporating with the magnetic bio-separator consisting of 2-dimension twisted microcoils. Notably, the magnetic bio-separators are developed either to generate the required magnetic field to perform the separation of magnetic beads or to work as a micro-heater to control the temperature field for the following RT process. Experimental results show that the total RNA can be successfully purified and extracted by using magnetic beads and the subsequent RT processing of the RNA can be performed automatically. Total RNA is successfully extracted and purified from T98 cells utilizing the microfluidic system, which is comparable with the conventional methods. The whole automatic procedure of RNA sample extraction only takes 35 min, which is much faster than the conventional method (more than 2 h). As a whole, the developed microfluidic system may provide a powerful platform for rapid RNA extraction and RT processes for further biomedical applications.
Collapse
|
49
|
An integrated microfluidic system for C-reactive protein measurement. Biosens Bioelectron 2009; 24:3091-6. [PMID: 19403298 DOI: 10.1016/j.bios.2009.03.034] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Revised: 03/06/2009] [Accepted: 03/25/2009] [Indexed: 11/20/2022]
Abstract
This study presents a new microfluidic chip integrated with pneumatic micropumps, normally close microvalves and vortex-type micromixers for C-reactive protein (CRP) measurement. CRP is a protein produced during the inflammation process. It has been reported that CRP in serum can be used for risk assessment of cardiovascular diseases. In this study, CRP measurements were performed by using the integrated microfluidic chip incorporated with magnetic beads. The magnetic beads coated with CRP-specific DNA aptamers were used to recognize, purify and enrich the target CRP. The entire process including sample pre-treatment, and the interaction between the target CRP and anti-CRP antibody was automatically performed on a single chip. The chemiluminescence signal was measured using a luminometer to detect the concentration of CRP afterwards. The entire reaction time is less then 25 min, which is only about 20% of the time required when compared to using traditional bench-top machines (150 min). More importantly, the detection limit has been improved from 0.125 to 0.0125 mg/L with only half the amount of reagent consumption. The development of this microfluidic system is promising for fast, accurate, and sensitive detection of CRP.
Collapse
|
50
|
Schulze H, Giraud G, Crain J, Bachmann TT. Multiplexed optical pathogen detection with lab-on-a-chip devices. JOURNAL OF BIOPHOTONICS 2009; 2:199-211. [PMID: 19367588 DOI: 10.1002/jbio.200910009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Infectious diseases are still a main cause of human morbidity and mortality. Advanced diagnostics is considered to be a key driver to improve the respective therapeutic outcome. The main factors influencing the impact of diagnostics include: assay speed, availability, information content, in-vitro diagnostics and cost, for which molecular assays are providing the most promising opportunities. Miniaturisation and integration of assay steps into lab-on-a-chip devices has been described as an appropriate way to speed up assay time and make assays available onsite at competitive costs. As meaningful assays for infectious diseases need to include a whole range of clinical relevant information about the pathogen, multiplexed functionality is often required for which optical transduction is particularly well suited. The aim of this review is to assess existing developments in this field and to give an outlook on future requirements and solutions.
Collapse
Affiliation(s)
- Holger Schulze
- Division of Pathway Medicine, Medical School, The University of Edinburgh, Edinburgh, Scotland UK
| | | | | | | |
Collapse
|