1
|
Saha S, Özden C, Samkutty A, Russi S, Cohen A, Stratton MM, Perry SL. Polymer-based microfluidic device for on-chip counter-diffusive crystallization and in situ X-ray crystallography at room temperature. LAB ON A CHIP 2023; 23:2075-2090. [PMID: 36942575 PMCID: PMC10631519 DOI: 10.1039/d2lc01194h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Proteins are long chains of amino acid residues that perform a myriad of functions in living organisms, including enzymatic reactions, signalling, and maintaining structural integrity. Protein function is determined directly by the protein structure. X-ray crystallography is the primary technique for determining the 3D structure of proteins, and facilitates understanding the effects of protein structure on function. The first step towards structure determination is crystallizing the protein of interest. We have developed a centrifugally-actuated microfluidic device that incorporates the fluid handling and metering necessary for protein crystallization. Liquid handling takes advantage of surface forces to control fluid flow and enable metering, without the need for any fluidic or pump connections. Our approach requires only the simple steps of pipetting the crystallization reagents into the device followed by either spinning or shaking to set up counter-diffusive protein crystallization trials. The use of thin, UV-curable polymers with a high level of X-ray transparency allows for in situ X-ray crystallography, eliminating the manual handling of fragile protein crystals and streamlining the process of protein structure analysis. We demonstrate the utility of our device using hen egg white lysozyme as a model system, followed by the crystallization and in situ, room temperature structural analysis of the hub domain of calcium-calmodulin dependent kinase II (CaMKIIβ).
Collapse
Affiliation(s)
- Sarthak Saha
- Department of Chemical Engineering, University of Massachusetts Amherst, MA 01003, USA.
| | - Can Özden
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, MA 01003, USA
| | - Alfred Samkutty
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, MA 01003, USA
| | - Silvia Russi
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Aina Cohen
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Margaret M Stratton
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, MA 01003, USA
| | - Sarah L Perry
- Department of Chemical Engineering, University of Massachusetts Amherst, MA 01003, USA.
| |
Collapse
|
2
|
Driver R, Mishra S. Organ-On-A-Chip Technology: An In-depth Review of Recent Advancements and Future of Whole Body-on-chip. BIOCHIP JOURNAL 2022. [DOI: 10.1007/s13206-022-00087-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
3
|
Bremer A, Mittag T, Heymann M. Microfluidic characterization of macromolecular liquid-liquid phase separation. LAB ON A CHIP 2020; 20:4225-4234. [PMID: 33057557 PMCID: PMC7658026 DOI: 10.1039/d0lc00613k] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Liquid-liquid phase separation plays important roles in the compartmentalization of cells. Developing an understanding of how phase separation is encoded in biomacromolecules requires quantitative mapping of their phase behavior. Given that such experiments require large quantities of the biomolecule of interest, these efforts have been lagging behind the recent breadth of biological insights. Herein, we present a microfluidic phase chip that enables the measurement of saturation concentrations over at least three orders of magnitude for a broad spectrum of biomolecules and solution conditions. The phase chip consists of five units, each made of twenty individual sample chambers to allow the measurement of five sample conditions simultaneously. The analytes are slowly concentrated via evaporation of water, which is replaced by oil, until the sample undergoes phase separation into a dilute and dense phase. We show that the phase chip lowers the required sample quantity by 98% while offering six-fold better statistics in comparison to standard manual experiments that involve centrifugal separation of dilute and dense phases. We further show that the saturation concentrations measured in chips are in agreement with previously reported data for a variety of biomolecules. Concomitantly, time-dependent changes of the dense phase morphology and potential off-pathway processes, including aggregation, can be monitored microscopically. In summary, the phase chip is suited to exploring sequence-to-binodal relationships by enabling the determination of a large number of saturation concentrations at low protein cost.
Collapse
Affiliation(s)
- Anne Bremer
- Department of Structural Biology, St. Jude Children's Research Hospital Memphis, TN, USA.
| | - Tanja Mittag
- Department of Structural Biology, St. Jude Children's Research Hospital Memphis, TN, USA.
| | - Michael Heymann
- Institute for Biomaterials and Biomolecular Systems, University Stuttgart, Germany.
| |
Collapse
|
4
|
Abstract
Obtaining diffracting quality crystals remains a major challenge in protein structure research. We summarize and compare methods for selecting the best protein targets for crystallization, construct optimization and crystallization condition design. Target selection methods are divided into algorithms predicting the chance of successful progression through all stages of structural determination (from cloning to solving the structure) and those focusing only on the crystallization step. We tried to highlight pros and cons of different approaches examining the following aspects: data size, redundancy and representativeness, overfitting during model construction, and results evaluation. In summary, although in recent years progress was made and several sequence properties were reported to be relevant for crystallization, the successful prediction of protein crystallization behavior and selection of corresponding crystallization conditions continue to challenge structural researchers.
Collapse
|
5
|
Bao B, Riordon J, Mostowfi F, Sinton D. Microfluidic and nanofluidic phase behaviour characterization for industrial CO 2, oil and gas. LAB ON A CHIP 2017; 17:2740-2759. [PMID: 28731086 DOI: 10.1039/c7lc00301c] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Microfluidic systems that leverage unique micro-scale phenomena have been developed to provide rapid, accurate and robust analysis, predominantly for biomedical applications. These attributes, in addition to the ability to access high temperatures and pressures, have motivated recent expanded applications in phase measurements relevant to industrial CO2, oil and gas applications. We here present a comprehensive review of this exciting new field, separating microfluidic and nanofluidic approaches. Microfluidics is practical, and provides similar phase properties analysis to established bulk methods with advantages in speed, control and sample size. Nanofluidic phase behaviour can deviate from bulk measurements, which is of particular relevance to emerging unconventional oil and gas production from nanoporous shale. In short, microfluidics offers a practical, compelling replacement of current bulk phase measurement systems, whereas nanofluidics is not practical, but uniquely provides insight into phase change phenomena at nanoscales. Challenges, trends and opportunities for phase measurements at both scales are highlighted.
Collapse
Affiliation(s)
- Bo Bao
- Interface Fluidics, 11421 Saskatchewan Dr. NW, Edmonton, Alberta, Canada
| | | | | | | |
Collapse
|
6
|
Ghazal A, Lafleur JP, Mortensen K, Kutter JP, Arleth L, Jensen GV. Recent advances in X-ray compatible microfluidics for applications in soft materials and life sciences. LAB ON A CHIP 2016; 16:4263-4295. [PMID: 27731448 DOI: 10.1039/c6lc00888g] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The increasingly narrow and brilliant beams at X-ray facilities reduce the requirements for both sample volume and data acquisition time. This creates new possibilities for the types and number of sample conditions that can be examined but simultaneously increases the demands in terms of sample preparation. Microfluidic-based sample preparation techniques have emerged as elegant alternatives that can be integrated directly into the experimental X-ray setup remedying several shortcomings of more traditional methods. We review the use of microfluidic devices in conjunction with X-ray measurements at synchrotron facilities in the context of 1) mapping large parameter spaces, 2) performing time resolved studies of mixing-induced kinetics, and 3) manipulating/processing samples in ways which are more demanding or not accessible on the macroscale. The review covers the past 15 years and focuses on applications where synchrotron data collection is performed in situ, i.e. directly on the microfluidic platform or on a sample jet from the microfluidic device. Considerations such as the choice of materials and microfluidic designs are addressed. The combination of microfluidic devices and measurements at large scale X-ray facilities is still emerging and far from mature, but it definitely offers an exciting array of new possibilities.
Collapse
Affiliation(s)
- Aghiad Ghazal
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark.
| | - Josiane P Lafleur
- Dept. of Pharmacy, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Kell Mortensen
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark.
| | - Jörg P Kutter
- Dept. of Pharmacy, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Lise Arleth
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark.
| | - Grethe V Jensen
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark.
| |
Collapse
|
7
|
Sui S, Wang Y, Kolewe KW, Srajer V, Henning R, Schiffman JD, Dimitrakopoulos C, Perry SL. Graphene-based microfluidics for serial crystallography. LAB ON A CHIP 2016; 16:3082-96. [PMID: 27241728 PMCID: PMC4970872 DOI: 10.1039/c6lc00451b] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Microfluidic strategies to enable the growth and subsequent serial crystallographic analysis of micro-crystals have the potential to facilitate both structural characterization and dynamic structural studies of protein targets that have been resistant to single-crystal strategies. However, adapting microfluidic crystallization platforms for micro-crystallography requires a dramatic decrease in the overall device thickness. We report a robust strategy for the straightforward incorporation of single-layer graphene into ultra-thin microfluidic devices. This architecture allows for a total material thickness of only ∼1 μm, facilitating on-chip X-ray diffraction analysis while creating a sample environment that is stable against significant water loss over several weeks. We demonstrate excellent signal-to-noise in our X-ray diffraction measurements using a 1.5 μs polychromatic X-ray exposure, and validate our approach via on-chip structure determination using hen egg white lysozyme (HEWL) as a model system. Although this work is focused on the use of graphene for protein crystallography, we anticipate that this technology should find utility in a wide range of both X-ray and other lab on a chip applications.
Collapse
Affiliation(s)
- Shuo Sui
- Department of Chemical Engineering, The University of Massachusetts Amherst, Amherst, MA 01003, USA.
| | - Yuxi Wang
- Department of Chemical Engineering, The University of Massachusetts Amherst, Amherst, MA 01003, USA.
| | - Kristopher W Kolewe
- Department of Chemical Engineering, The University of Massachusetts Amherst, Amherst, MA 01003, USA.
| | - Vukica Srajer
- BioCARS Center for Advanced Radiation Sources, The University of Chicago, Argonne, IL 60439, USA
| | - Robert Henning
- BioCARS Center for Advanced Radiation Sources, The University of Chicago, Argonne, IL 60439, USA
| | - Jessica D Schiffman
- Department of Chemical Engineering, The University of Massachusetts Amherst, Amherst, MA 01003, USA.
| | - Christos Dimitrakopoulos
- Department of Chemical Engineering, The University of Massachusetts Amherst, Amherst, MA 01003, USA.
| | - Sarah L Perry
- Department of Chemical Engineering, The University of Massachusetts Amherst, Amherst, MA 01003, USA.
| |
Collapse
|
8
|
Wu AR, Quake SR. Microfluidics Technologies for Low Cell Number Chromatin Immunoprecipitation. Cold Spring Harb Protoc 2016; 2016:pdb.prot084996. [PMID: 26700100 DOI: 10.1101/pdb.prot084996] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Protein-DNA interactions are responsible for numerous critical cellular events: For example, gene expression and silencing are mediated by transcription factor protein binding and histone protein modifications, and DNA replication and repair rely on site-specific protein binding. Chromatin immunoprecipitation (ChIP) is the only molecular assay that directly determines, in a living cell, the binding association between a protein of interest and specific genomic loci. It is an indispensible tool in the biologist's toolbox, but the many limitations of this technique prevent broad adoption of ChIP in biological studies. The typical ChIP assay can take up to 1 wk to complete, and the process is technically tricky, yet tedious. The ChIP assay yields are also low, thus requiring on the order of millions to billions of cells as starting material, which makes the assay unfeasible for studies using rare or precious samples. For example, fluorescence-activated cell sorting (FACS) of cancer stem cells (CSCs) obtained from primary tumors, rarely yields more than ~100,000 CSCs per tumor. This protocol describes a microfluidics-based strategy for performing ChIP, which uses automation and scalability to reduce both total and hands-on assay time, and improve throughput. It allows whole fixed cells as input, and enables automated ChIP from as few as 2000 cells.
Collapse
Affiliation(s)
- Angela R Wu
- Department of Bioengineering, Stanford University, Stanford, California 94305
| | - Stephen R Quake
- Department of Bioengineering, Stanford University, Stanford, California 94305; Howard Hughes Medical Institute, Stanford, California 94305
| |
Collapse
|
9
|
Altan I, Charbonneau P, Snell EH. Computational crystallization. Arch Biochem Biophys 2016; 602:12-20. [PMID: 26792536 DOI: 10.1016/j.abb.2016.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 12/22/2015] [Accepted: 01/07/2016] [Indexed: 11/28/2022]
Abstract
Crystallization is a key step in macromolecular structure determination by crystallography. While a robust theoretical treatment of the process is available, due to the complexity of the system, the experimental process is still largely one of trial and error. In this article, efforts in the field are discussed together with a theoretical underpinning using a solubility phase diagram. Prior knowledge has been used to develop tools that computationally predict the crystallization outcome and define mutational approaches that enhance the likelihood of crystallization. For the most part these tools are based on binary outcomes (crystal or no crystal), and the full information contained in an assembly of crystallization screening experiments is lost. The potential of this additional information is illustrated by examples where new biological knowledge can be obtained and where a target can be sub-categorized to predict which class of reagents provides the crystallization driving force. Computational analysis of crystallization requires complete and correctly formatted data. While massive crystallization screening efforts are under way, the data available from many of these studies are sparse. The potential for this data and the steps needed to realize this potential are discussed.
Collapse
Affiliation(s)
- Irem Altan
- Department of Chemistry, Duke University, Durham, NC 27708, USA
| | - Patrick Charbonneau
- Department of Chemistry, Duke University, Durham, NC 27708, USA; Department of Physics, Duke University, Durham, NC 27708, USA
| | - Edward H Snell
- Hauptman-Woodward Medical Research Institute, 700 Ellicott St., NY 14203, USA; Department of Structural Biology, SUNY University of Buffalo, 700 Ellicott St., NY 14203, USA.
| |
Collapse
|
10
|
Fusco D, Charbonneau P. Soft matter perspective on protein crystal assembly. Colloids Surf B Biointerfaces 2016; 137:22-31. [DOI: 10.1016/j.colsurfb.2015.07.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 07/07/2015] [Accepted: 07/09/2015] [Indexed: 01/24/2023]
|
11
|
Wu P, Noland C, Ultsch M, Edwards B, Harris D, Mayer R, Harris SF. Developments in the Implementation of Acoustic Droplet Ejection for Protein Crystallography. ACTA ACUST UNITED AC 2015; 21:97-106. [PMID: 26275619 DOI: 10.1177/2211068215598938] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Indexed: 11/16/2022]
Abstract
Acoustic droplet ejection (ADE) enables crystallization experiments at the low-nanoliter scale, resulting in rapid vapor diffusion equilibration dynamics and efficient reagent usage in the empirical discovery of structure-enabling protein crystallization conditions. We extend our validation of this technology applied to the diverse physicochemical property space of aqueous crystallization reagents where dynamic fluid analysis coupled to ADE aids in accurate and precise dispensations. Addition of crystallization seed stocks, chemical additives, or small-molecule ligands effectively modulates crystallization, and we here provide examples in optimization of crystal morphology and diffraction quality by the acoustic delivery of ultra-small volumes of these cofactors. Additional applications are discussed, including set up of in situ proteolysis and alternate geometries of crystallization that leverage the small scale afforded by acoustic delivery. Finally, we describe parameters of a system of automation in which the acoustic liquid handler is integrated with a robotic arm, plate centrifuge, peeler, sealer, and stacks, which allows unattended high-throughput crystallization experimentation.
Collapse
Affiliation(s)
- Ping Wu
- Department of Structural Biology, Genentech, Inc, South San Francisco, CA, USA
| | - Cameron Noland
- Department of Structural Biology, Genentech, Inc, South San Francisco, CA, USA
| | - Mark Ultsch
- Department of Structural Biology, Genentech, Inc, South San Francisco, CA, USA
| | | | | | - Robert Mayer
- Department of Structural Biology, Genentech, Inc, South San Francisco, CA, USA
| | - Seth F Harris
- Department of Structural Biology, Genentech, Inc, South San Francisco, CA, USA
| |
Collapse
|
12
|
Gorrec F. Progress in macromolecular crystallography depends on further miniaturization of crystallization experiments. Drug Discov Today 2014; 19:1505-7. [PMID: 25048082 DOI: 10.1016/j.drudis.2014.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 07/01/2014] [Accepted: 07/03/2014] [Indexed: 01/08/2023]
Affiliation(s)
- Fabrice Gorrec
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK.
| |
Collapse
|
13
|
Berg A, Schuetz M, Dismer F, Hubbuch J. Automated measurement of apparent protein solubility to rapidly assess complex parameter interactions. FOOD AND BIOPRODUCTS PROCESSING 2014. [DOI: 10.1016/j.fbp.2013.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
14
|
Fusco D, Headd JJ, De Simone A, Wang J, Charbonneau P. Characterizing protein crystal contacts and their role in crystallization: rubredoxin as a case study. SOFT MATTER 2014; 10:290-302. [PMID: 24489597 PMCID: PMC3907588 DOI: 10.1039/c3sm52175c] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The fields of structural biology and soft matter have independently sought out fundamental principles to rationalize protein crystallization. Yet the conceptual differences and the limited overlap between the two disciplines have thus far prevented a comprehensive understanding of the phenomenon to emerge. We conduct a computational study of proteins from the rubredoxin family that bridges the two fields. Using atomistic simulations, we characterize the protein crystal contacts, and accordingly parameterize patchy particle models. Comparing the phase diagrams of these schematic models with experimental results enables us to critically examine the assumptions behind the two approaches. The study also reveals features of protein–protein interactions that can be leveraged to crystallize proteins more generally.
Collapse
Affiliation(s)
- Diana Fusco
- Program in Computational Biology and Bioinformatics, Duke University, Durham, NC 27708, USA
| | - Jeffrey J. Headd
- Department of Biochemistry, Duke University, Durham, NC 27708, USA
| | - Alfonso De Simone
- Division of Molecular Biosciences, Imperial College London, South Kensington SW7 2AZ, UK
| | - Jun Wang
- Department of Chemistry, Duke University, Durham, NC 27708, USA
| | - Patrick Charbonneau
- Program in Computational Biology and Bioinformatics, Duke University, Durham, NC 27708, USA
- Department of Chemistry, Duke University, Durham, NC 27708, USA
- Department of Physics, Duke University, Durham, NC 27708, USA
| |
Collapse
|
15
|
Pneumatic oscillator circuits for timing and control of integrated microfluidics. Proc Natl Acad Sci U S A 2013; 110:18104-9. [PMID: 24145429 DOI: 10.1073/pnas.1310254110] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Frequency references are fundamental to most digital systems, providing the basis for process synchronization, timing of outputs, and waveform synthesis. Recently, there has been growing interest in digital logic systems that are constructed out of microfluidics rather than electronics, as a possible means toward fully integrated laboratory-on-a-chip systems that do not require any external control apparatus. However, the full realization of this goal has not been possible due to the lack of on-chip frequency references, thus requiring timing signals to be provided from off-chip. Although microfluidic oscillators have been demonstrated, there have been no reported efforts to characterize, model, or optimize timing accuracy, which is the fundamental metric of a clock. Here, we report pneumatic ring oscillator circuits built from microfluidic valves and channels. Further, we present a compressible-flow analysis that differs fundamentally from conventional circuit theory, and we show the utility of this physically based model for the optimization of oscillator stability. Finally, we leverage microfluidic clocks to demonstrate circuits for the generation of phase-shifted waveforms, self-driving peristaltic pumps, and frequency division. Thus, pneumatic oscillators can serve as on-chip frequency references for microfluidic digital logic circuits. On-chip clocks and pumps both constitute critical building blocks on the path toward achieving autonomous laboratory-on-a-chip devices.
Collapse
|
16
|
Khvostichenko DS, Kondrashkina E, Perry SL, Pawate AS, Brister K, Kenis PJ. An X-ray transparent microfluidic platform for screening of the phase behavior of lipidic mesophases. Analyst 2013; 138:5384-95. [PMID: 23882463 PMCID: PMC3800112 DOI: 10.1039/c3an01174g] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Lipidic mesophases are a class of highly ordered soft materials that form when certain lipids are mixed with water. Understanding the relationship between the composition and the microstructure of mesophases is necessary for fundamental studies of self-assembly in amphiphilic systems and for applications, such as the crystallization of membrane proteins. However, the laborious formulation protocol for highly viscous mesophases and the large amounts of material required for sample formulation are significant obstacles in such studies. Here we report a microfluidic platform that facilitates investigations of the phase behavior of mesophases by reducing sample consumption 300-fold, and automating and parallelizing sample formulation. The mesophases were formulated on-chip using less than 80 nL of material per sample and their microstructure was analyzed in situ using small-angle X-ray scattering (SAXS). The 220 μm-thick X-ray compatible platform was comprised of thin polydimethylsiloxane (PDMS) layers sandwiched between cyclic olefin copolymer (COC) sheets. Uniform mesophases were prepared using an active on-chip mixing strategy coupled with periodic cooling of the sample to reduce viscosity. We validated the platform by preparing and analyzing mesophases of the lipid monoolein (MO) mixed with aqueous solutions of different concentrations of β-octylglucoside (βOG), a detergent frequently used in membrane protein crystallization. Four samples were prepared in parallel on chip, by first metering and automatically diluting βOG to obtain detergent solutions of different concentration, then metering MO, and finally mixing by actuation of pneumatic valves. Integration of detergent dilution and subsequent mixing significantly reduced the number of manual steps needed for sample preparation. Three different types of mesophases typical for MO were successfully identified in SAXS data from on-chip samples. Microstructural parameters of identical samples formulated in different chips showed excellent agreement. Phase behavior of samples on-chip (~80 nL per sample) corresponded well with that of samples prepared via the traditional coupled-syringe method using at least two orders of magnitude more material ("off-chip", 35-40 μL per sample), further validating the applicability of the microfluidic platform for on-chip characterization of mesophase microstructure.
Collapse
Affiliation(s)
- Daria S. Khvostichenko
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Matthews Avenue, Urbana, IL, 61801 USA. Tel:+1-217-265-0523
| | - Elena Kondrashkina
- Northwestern University, Synchrotron Research Center, LS-CAT, Argonne, IL, USA. Fax: +1-630-252-4664; Tel: +1-630-343-9532
| | - Sarah L. Perry
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Matthews Avenue, Urbana, IL, 61801 USA. Tel:+1-217-265-0523
| | - Ashtamurthy S. Pawate
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Matthews Avenue, Urbana, IL, 61801 USA. Tel:+1-217-265-0523
| | - Keith Brister
- Northwestern University, Synchrotron Research Center, LS-CAT, Argonne, IL, USA. Fax: +1-630-252-4664; Tel: +1-630-343-9532
| | - Paul J.A. Kenis
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Matthews Avenue, Urbana, IL, 61801 USA. Tel:+1-217-265-0523
| |
Collapse
|
17
|
Perry SL, Guha S, Pawate AS, Bhaskarla A, Agarwal V, Nair SK, Kenis PJ. A microfluidic approach for protein structure determination at room temperature via on-chip anomalous diffraction. LAB ON A CHIP 2013; 13:3183-7. [PMID: 23828485 PMCID: PMC3755953 DOI: 10.1039/c3lc50276g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We report a microfluidic approach for de novo protein structure determination via crystallization screening and optimization, as well as on-chip X-ray diffraction data collection. The structure of phosphonoacetate hydrolase (PhnA) has been solved to 2.11 Åvia on-chip collection of anomalous data that has an order of magnitude lower mosaicity than what is typical for traditional structure determination methods.
Collapse
Affiliation(s)
- Sarah L. Perry
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, USA
| | - Sudipto Guha
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, USA
| | - Ashtamurthy S. Pawate
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, USA
| | - Amrit Bhaskarla
- School of Molecular & Cellular Biology, University of Illinois at Urbana-Champaign, USA
| | - Vinayak Agarwal
- Department of Biochemistry, University of Illinois at Urbana-Champaign, USA
| | - Satish K. Nair
- Department of Biochemistry, University of Illinois at Urbana-Champaign, USA
| | - Paul J.A. Kenis
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana-Champaign, USA
| |
Collapse
|
18
|
|
19
|
Daubersies L, Leng J, Salmon JB. Steady and out-of-equilibrium phase diagram of a complex fluid at the nanolitre scale: combining microevaporation, confocal Raman imaging and small angle X-ray scattering. LAB ON A CHIP 2013; 13:910-919. [PMID: 23319166 DOI: 10.1039/c2lc41207a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We engineered specific microfluidic devices based on the pervaporation of water through a PDMS membrane, to formulate continuous and steady concentration gradients of a binary aqueous molecular mixture at the nanolitre scale. In the case of a model complex fluid (a triblock copolymer solution), we demonstrate that such a steady gradient crosses the phase diagram from pure water up to a succession of highly viscous mesophases. We then performed in situ spatially resolved measurements (confocal spectroscopy and small-angle X-ray scattering) to quantitatively measure the concentration profile and to determine the microstructure of the different textures. Within a single microfluidic channel, we thus screen quantitatively and continuously the phase diagram of a complex fluid. Beside, as such a gradient corresponds to an out-of-equilibrium regime, we also extract from the concentration measurement a precise estimate of the collective diffusion coefficient of the mixture as a function of the concentration. In the present case of the triblock copolymer, this transport coefficient features discontinuities at some phase boundaries, which have never been observed before.
Collapse
|
20
|
Streets AM, Huang Y. Chip in a lab: Microfluidics for next generation life science research. BIOMICROFLUIDICS 2013; 7:11302. [PMID: 23460772 PMCID: PMC3574129 DOI: 10.1063/1.4789751] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 01/14/2013] [Indexed: 05/06/2023]
Abstract
Microfluidic circuits are characterized by fluidic channels and chambers with a linear dimension on the order of tens to hundreds of micrometers. Components of this size enable lab-on-a-chip technology that has much promise, for example, in the development of point-of-care diagnostics. Micro-scale fluidic circuits also yield practical, physical, and technological advantages for studying biological systems, enhancing the ability of researchers to make more precise quantitative measurements. Microfluidic technology has thus become a powerful tool in the life science research laboratory over the past decade. Here we focus on chip-in-a-lab applications of microfluidics and survey some examples of how small fluidic components have provided researchers with new tools for life science research.
Collapse
Affiliation(s)
- Aaron M Streets
- Biodynamic Optical Imaging Center (BIOPIC), Peking University, Beijing 100871, China ; College of Engineering, Peking University, Beijing 100871, China
| | | |
Collapse
|
21
|
Dolega ME, Jakiela S, Razew M, Rakszewska A, Cybulski O, Garstecki P. Iterative operations on microdroplets and continuous monitoring of processes within them; determination of solubility diagrams of proteins. LAB ON A CHIP 2012; 12:4022-5. [PMID: 22868285 DOI: 10.1039/c2lc40174f] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We demonstrate a technique for controlling the content of multiple microdroplets in time. We use this system to rapidly and quantiatively determine the solubility diagrams of two model proteins (lysozyme and ribonuclease A).
Collapse
Affiliation(s)
- Monika E Dolega
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | | | | | | | | | | |
Collapse
|
22
|
Luft JR, Wolfley JR, Snell EH. What's in a drop? Correlating observations and outcomes to guide macromolecular crystallization experiments. CRYSTAL GROWTH & DESIGN 2011; 11:651-663. [PMID: 21643490 PMCID: PMC3106348 DOI: 10.1021/cg1013945] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Observations of crystallization experiments are classified as specific outcomes and integrated through a phase diagram to visualize solubility and thereby direct subsequent experiments. Specific examples are taken from our high-throughput crystallization laboratory which provided a broad scope of data from 20 million crystallization experiments on 12,500 different biological macromolecules. The methods and rationale are broadly and generally applicable in any crystallization laboratory. Through a combination of incomplete factorial sampling of crystallization cocktails, standard outcome classifications, visualization of outcomes as they relate chemically and application of a simple phase diagram approach we demonstrate how to logically design subsequent crystallization experiments.
Collapse
Affiliation(s)
- Joseph R. Luft
- Hauptman-Woodward Medical Research Institute, 700 Ellicott St., Buffalo, NY 14203, USA
- Department of Computational and Structural Biology, SUNY Buffalo, 700 Ellicott St., Buffalo, NY 14203, USA
| | - Jennifer R. Wolfley
- Hauptman-Woodward Medical Research Institute, 700 Ellicott St., Buffalo, NY 14203, USA
| | - Edward H. Snell
- Hauptman-Woodward Medical Research Institute, 700 Ellicott St., Buffalo, NY 14203, USA
- Department of Computational and Structural Biology, SUNY Buffalo, 700 Ellicott St., Buffalo, NY 14203, USA
| |
Collapse
|
23
|
Barikbin Z, Rahman MT, Parthiban P, Rane AS, Jain V, Duraiswamy S, Lee SHS, Khan SA. Ionic liquid-based compound droplet microfluidics for 'on-drop' separations and sensing. LAB ON A CHIP 2010; 10:2458-2463. [PMID: 20697661 DOI: 10.1039/c004853d] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We present a new and general scheme for analytical applications of droplet-based microfluidics in which flowing droplets function not only as isolated reaction flasks, but are also capable of on-drop separation and sensing. To demonstrate this, we choose ionic liquids as designer fluids whose chemical and physical properties can be tailored in task-specific fashion. We create aqueous-ionic liquid compound droplets with tunable structures using an imidazolium-based ionic liquid, and present two analytical applications-separation of a binary aqueous mixture of organic dyes and dynamic pH sensing-to highlight the salient features of this scheme. By combining designer fluids with designer microfluidic emulsions, our work opens up a rich space of exploration for analytical microfluidics.
Collapse
|
24
|
Kim B, Song J, Song X. Calculations of the binding affinities of protein-protein complexes with the fast multipole method. J Chem Phys 2010; 133:095101. [DOI: 10.1063/1.3474624] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
25
|
Li L, Ismagilov RF. Protein crystallization using microfluidic technologies based on valves, droplets, and SlipChip. Annu Rev Biophys 2010; 39:139-58. [PMID: 20192773 DOI: 10.1146/annurev.biophys.050708.133630] [Citation(s) in RCA: 148] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To obtain protein crystals, researchers must search for conditions in multidimensional chemical space. Empirically, thousands of crystallization experiments are carried out to screen various precipitants at multiple concentrations. Microfluidics can manipulate fluids on a nanoliter scale, and it affects crystallization twofold. First, it miniaturizes the experiments that can currently be done on a larger scale and enables crystallization of proteins that are available only in small amounts. Second, it offers unique experimental approaches that are difficult or impossible to implement on a larger scale. Ongoing development of microfluidic techniques and their integration with protein production, characterization, and in situ diffraction promises to accelerate the progress of structural biology.
Collapse
Affiliation(s)
- Liang Li
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | | |
Collapse
|
26
|
Huang Y, Reimann J, Singh LM, Ädelroth P. Substrate binding and the catalytic reactions in cbb3-type oxidases: The lipid membrane modulates ligand binding. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:724-31. [DOI: 10.1016/j.bbabio.2010.03.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Revised: 03/11/2010] [Accepted: 03/12/2010] [Indexed: 11/25/2022]
|
27
|
Abstract
Obtaining well-diffracting crystals remains a major challenge in protein structure research. In this chapter, we review currently available computational methods to estimate the crystallization potential of a protein, to optimize amino acid sequences toward improved crystallization likelihood, and to design optimal crystal screen conditions.
Collapse
|
28
|
Abstract
We describe a model for protein crystallization equilibria. The model includes four terms, (1) protein translational entropy opposes crystallization, (2) proteins are attracted to each other by a nonelectrostatic contact free energy favoring crystallization, (3) proteins in the crystal repel each other but, to a greater extent, attract counterions sequestered in the crystal, which favors crystallization, and (4) the translational entropy of the counterions opposes their sequestration into the crystal, opposing crystallization. We treat the electrostatics using the nonlinear Poisson-Boltzmann equation, and we use unit cell information from native protein crystals to determine the boundary conditions. This model predicts the stabilities of protein crystals as functions of temperature, pH, and salt concentrations, in good agreement with the data of Pusey et al. on tetragonal and orthorhombic crystal forms of lysozyme. The experiments show a weak dependence of crystal solubility on pH. According to the model, this is because the entropic cost to neutralize the crystal is compensated by favorable protein-salt interactions. Experiments also show that adding salt stabilizes the crystal. Cohn's empirical law predicts that the logarithm of solubility should be a linear function of salt. The present theory predicts nonlinearity, in better agreement with the experiments. The model shows that the salting out phenomena is not due to more counterion shielding but to lowered counterion translational entropy. Models of this type may help guide faster and better ways to crystallize proteins.
Collapse
Affiliation(s)
- Jeremy D. Schmit
- Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, CA 94158
| | - Ken A. Dill
- Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, CA 94158
| |
Collapse
|
29
|
Li L, Du W, Ismagilov RF. Multiparameter screening on SlipChip used for nanoliter protein crystallization combining free interface diffusion and microbatch methods. J Am Chem Soc 2010; 132:112-9. [PMID: 20000709 PMCID: PMC2805062 DOI: 10.1021/ja908558m] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This paper describes two SlipChip-based approaches to protein crystallization: a SlipChip-based free interface diffusion (FID) method and a SlipChip-based composite method that simultaneously performs microbatch and FID crystallization methods in a single device. The FID SlipChip was designed to screen multiple reagents, each at multiple diffusion equilibration times, and was validated by screening conditions for crystallization of two proteins, enoyl-CoA hydratase from Mycobacterium tuberculosis and dihydrofolate reductase/thymidylate synthase from Babesia bovis, against 48 different reagents at five different equilibration times each, consuming 12 microL of each protein for a total of 480 experiments using three SlipChips. The composite SlipChip was designed to screen multiple reagents, each at multiple mixing ratios and multiple equilibration times, and was validated by screening conditions for crystallization of two proteins, enoyl-CoA hydratase from Mycobacterium tuberculosis and dihydrofolate reductase/thymidylate synthase from Babesia bovis. To prevent cross-contamination while keeping the solution in the neck channels for FID stable, the plates of the SlipChip were etched with a pattern of nanowells. This nanopattern was used to increase the contact angle of aqueous solutions on the surface of the silanized glass. The composite SlipChip increased the number of successful crystallization conditions and identified more conditions for crystallization than separate FID and microbatch screenings. Crystallization experiments were scaled up in well plates using conditions identified during the SlipChip screenings, and X-ray diffraction data were obtained to yield the protein structure of dihydrofolate reductase/thymidylate synthase at 1.95 A resolution. This free-interface diffusion approach provides a convenient and high-throughput method of setting up gradients in microfluidic devices and may find additional applications in cell-based assays.
Collapse
Affiliation(s)
- Liang Li
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 E 57th St, Chicago, Illinois 60637
| | - Wenbin Du
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 E 57th St, Chicago, Illinois 60637
| | - Rustem F. Ismagilov
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 E 57th St, Chicago, Illinois 60637
| |
Collapse
|
30
|
Mark D, Haeberle S, Roth G, Von Stetten F, Zengerle R. Microfluidic Lab-on-a-Chip Platforms: Requirements, Characteristics and Applications. MICROFLUIDICS BASED MICROSYSTEMS 2010. [DOI: 10.1007/978-90-481-9029-4_17] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
31
|
Mark D, Haeberle S, Roth G, von Stetten F, Zengerle R. Microfluidic lab-on-a-chip platforms: requirements, characteristics and applications. Chem Soc Rev 2010; 39:1153-82. [PMID: 20179830 DOI: 10.1039/b820557b] [Citation(s) in RCA: 765] [Impact Index Per Article: 54.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Daniel Mark
- HSG-IMIT-Institut für Mikro- und Informationstechnik, Wilhelm-Schickard-Strasse 10, 78052 Villingen-Schwenningen, Germany
| | | | | | | | | |
Collapse
|
32
|
Dhouib K, Khan Malek C, Pfleging W, Gauthier-Manuel B, Duffait R, Thuillier G, Ferrigno R, Jacquamet L, Ohana J, Ferrer JL, Théobald-Dietrich A, Giegé R, Lorber B, Sauter C. Microfluidic chips for the crystallization of biomacromolecules by counter-diffusion and on-chip crystal X-ray analysis. LAB ON A CHIP 2009; 9:1412-21. [PMID: 19417908 DOI: 10.1039/b819362b] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Microfluidic devices were designed to perform on micromoles of biological macromolecules and viruses the search and the optimization of crystallization conditions by counter-diffusion, as well as the on-chip analysis of crystals by X-ray diffraction. Chips composed of microchannels were fabricated in poly-dimethylsiloxane (PDMS), poly-methyl-methacrylate (PMMA) and cyclo-olefin-copolymer (COC) by three distinct methods, namely replica casting, laser ablation and hot embossing. The geometry of the channels was chosen to ensure that crystallization occurs in a convection-free environment. The transparency of the materials is compatible with crystal growth monitoring by optical microscopy. The quality of the protein 3D structures derived from on-chip crystal analysis by X-ray diffraction using a synchrotron radiation was used to identify the most appropriate polymers. Altogether the results demonstrate that for a novel biomolecule, all steps from the initial search of crystallization conditions to X-ray diffraction data collection for 3D structure determination can be performed in a single chip.
Collapse
Affiliation(s)
- Kaouthar Dhouib
- Architecture et réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 15 rue René Descartes, F-67084, Strasbourg, France
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Abstract
Microfluidics offers a wide range of new tools that permit one to revisit the formation of crystals in solution and yield insights into crystallization processes. We review such recent microfluidic devices and particularly emphasize lab-on-chips dedicated to the high-throughput screening of crystallization conditions of proteins with nanolitre consumption. We also thoroughly discuss the possibilities offered by the microfluidic tools to acquire thermodynamic and kinetic data that may improve industrial processes and shed a new light on nucleation and growth mechanisms.
Collapse
Affiliation(s)
- Jacques Leng
- Université Bordeaux-1, Laboratoire du Futur, Pessac cedex, France
| | | |
Collapse
|
34
|
Chapter 8 Advances in Microfluidic Membrane Protein Crystallization Techniques. CURRENT TOPICS IN MEMBRANES 2009. [DOI: 10.1016/s1063-5823(09)63008-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
|
35
|
Witek MA, Hupert ML, Park DSW, Fears K, Murphy MC, Soper SA. 96-well polycarbonate-based microfluidic titer plate for high-throughput purification of DNA and RNA. Anal Chem 2008; 80:3483-91. [PMID: 18355091 DOI: 10.1021/ac8002352] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a simple and effective method for the high-throughput purification of a variety of nucleic acids (NAs) from whole cell lysates or whole blood using a photactivated polycarbonate solid-phase reversible immobilization (PPC-SPRI) microfluidic chip. High-throughput operation was achieved by placing 96 purification beds, each containing an array of 3800 20 microm diameter posts, on a single 3" x 5" polycarbonate (PC) wafer fabricated by hot embossing. All beds were interconnected through a common microfluidic network that permitted parallel access through the use of a vacuum and syringe pump for delivery of immobilization buffer (IB) and effluent. The PPC-SPRI purification was accomplished by condensation of NAs onto a UV-modified PC surface in the presence of the IB comprised of polyethylene glycol, NaCl, and ethanol with a composition dependent on the length of the NAs to be isolated and the identity of the sample matrix. The performance of the device was validated by quantification of the recovered material following PCR (for DNA) or RT-PCR (for RNA). The extraction bed load capacity of NAs was 206 +/- 93 ng for gDNA and 165 +/- 81 ng for TRNA from Escherichia coli. Plate-to-plate variability was found to be 35 +/- 10%. The purification process was fast (<30 min) and easy to automate, and the low cost of wafer fabrication makes it appropriate for single-use applications.
Collapse
Affiliation(s)
- Małgorzata A Witek
- Center for Bio-Modular Multi-Scale Systems, Louisiana State University and Agricultural and Mechanical College, 8000 GSRI Road, Baton Rouge, Louisiana 70820, USA
| | | | | | | | | | | |
Collapse
|
36
|
Abstract
Abstract
Background: Particle-based agglutination tests consisting of receptors grafted to colloidal microparticles are useful for detecting small quantities of corresponding ligands of interest in fluid test samples, but detection limits of such tests are limited to a certain concentration and it is most desirable to lower the detection limits and to enhance the rate of recognition of ligands.
Methods: A mixture of receptor-coated colloidal microparticles and corresponding ligand was sandwiched between 2 indium tin oxide–coated glass plates. Electrohydrodynamic drag from an alternating-current electric field applied perpendicular to the plates increased the local concentration of the colloidal particles, improving the chances of ligand-receptor interaction and leading to the aggregation of the colloidal particles.
Results: With this technique the sensitivity of the ligand-receptor recognition was increased by a factor as large as 50.
Conclusions: This method can improve the sensitivity of particle-based agglutination tests used in immunoassays and many other applications such as immunoprecipitation and chemical sniffing.
Collapse
Affiliation(s)
- Ajay Singh Negi
- Department of Physics, Indian Institute of Science, Bangalore, India
| | | |
Collapse
|
37
|
Mahmud G, Bishop KJM, Chegel Y, Smoukov SK, Grzybowski BA. Wet-stamped precipitant gradients control the growth of protein microcrystals in an array of nanoliter wells. J Am Chem Soc 2008; 130:2146-7. [PMID: 18225903 DOI: 10.1021/ja078051k] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Goher Mahmud
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA
| | | | | | | | | |
Collapse
|
38
|
Kang L, Chung BG, Langer R, Khademhosseini A. Microfluidics for drug discovery and development: from target selection to product lifecycle management. Drug Discov Today 2007; 13:1-13. [PMID: 18190858 DOI: 10.1016/j.drudis.2007.10.003] [Citation(s) in RCA: 209] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Revised: 10/01/2007] [Accepted: 10/05/2007] [Indexed: 01/09/2023]
Abstract
Microfluidic technologies' ability to miniaturize assays and increase experimental throughput have generated significant interest in the drug discovery and development domain. These characteristics make microfluidic systems a potentially valuable tool for many drug discovery and development applications. Here, we review the recent advances of microfluidic devices for drug discovery and development and highlight their applications in different stages of the process, including target selection, lead identification, preclinical tests, clinical trials, chemical synthesis, formulations studies and product management.
Collapse
Affiliation(s)
- Lifeng Kang
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | | | | |
Collapse
|
39
|
Shim JU, Cristobal G, Link DR, Thorsen T, Jia Y, Piattelli K, Fraden S. Control and measurement of the phase behavior of aqueous solutions using microfluidics. J Am Chem Soc 2007; 129:8825-35. [PMID: 17580868 PMCID: PMC2531156 DOI: 10.1021/ja071820f] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A microfluidic device denoted the Phase Chip has been designed to measure and manipulate the phase diagram of multicomponent fluid mixtures. The Phase Chip exploits the permeation of water through poly(dimethylsiloxane) (PDMS) in order to controllably vary the concentration of solutes in aqueous nanoliter volume microdrops stored in wells. The permeation of water in the Phase Chip is modeled using the diffusion equation, and good agreement between experiment and theory is obtained. The Phase Chip operates by first creating drops of the water/solute mixture whose composition varies sequentially. Next, drops are transported down channels and guided into storage wells using surface tension forces. Finally, the solute concentration of each stored drop is simultaneously varied and measured. Two applications of the Phase Chip are presented. First, the phase diagram of a polymer/salt mixture is measured on-chip and validated off-chip, and second, protein crystallization rates are enhanced through the manipulation of the kinetics of nucleation and growth.
Collapse
Affiliation(s)
| | - Galder Cristobal
- Department of Physics and HSEAS, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Darren R. Link
- Department of Physics and HSEAS, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Todd Thorsen
- Department of Mechanical Engineering, MIT, Cambridge, MA 02139, USA
| | | | | | | |
Collapse
|