Volume 13 | N

umber 13 | 2013

Lab on a Chip Themed issue: Focus on Canada

Pages 2421–2662 1473-0197(2013)13:13;1-W

ISSN 1473-0197

Lab on a ChipMiniaturisation for chemistry, physics, biology, materials science and bioengineering

www.rsc.org/loc Volume 13 | Number 13 | 7 July 2013 | Pages 2421–2662

Themed issue: Focus on Canada

OFC COVER SCAN

TO FIT INTO THIS BOX

www.rsc.org/locRegistered Charity Number 207890

Featuring work from the Laboratory of Prof. Axel

Guenther, University of Toronto, Canada.

Title: Bubble gate for in-plane fl ow control

Simultaneous operation of 128 miniature gate valves is used to controllably trap a red-coloured solution in a pattern that display the Maple Leaf, the National Flag of Canada. Bubble gates are miniature gate valves that provide for simple, substrate-independent and scalable control of liquid fl ow in microfl uidic devices.

EDITORIAL David Juncker, Aaron R. Wheeler, David Sinton Lab on a chip Canada – rapid dif fusion over large length scales

As featured in:

See Axel Günther et al., Lab Chip, 2013, 13, 2515.

LC013013_cover_PRINT.indd 1LC013013_cover_PRINT.indd 1 6/3/2013 12:24:18 PM6/3/2013 12:24:18 PM

Cite this: Lab Chip, 2013, 13, 2438

Lab on a chip Canada – rapid diffusion over large lengthscales

DOI: 10.1039/c3lc90052e

www.rsc.org/loc

David Juncker,*a Aaron R. Wheeler*b and David Sinton*c

The roots of lab on a chip in Canada are deep, comprising of some of the

earliest contributions and first demonstrations of the potential of

microfluidic chips. In an editorial leading off this special issue, Jed Harrison of

University of Alberta reflects on these early days and Canada’s role in the

field’s development (DOI: 10.1039/c3lc50522g). Over the last decade,

microfluidics and lab-on-a-chip research efforts grew exponentially – rapidly

diffusing across the vast Canadian length scales.

A recurring theme in the microfluidicscommunity is commercialization andthe discovery of the ‘‘killer app’’.

Among the Canadian vastness andmaple (syrup) trees, a factory the sizeof several football fields producesy140 000 labs-on-a-chip daily and gen-erates tens of millions in annual rev-enue. In 1983, Imants Lauks left afaculty position at the University ofPennsylvania and moved to Ottawa tolaunch Integrated Ionics Incorporated,commonly known as i-STAT. Lauks’pioneering vision that integrated anelectrochemical chip, a cartridge, and ahand-held reader with a pneumatic

actuation system to displace liquidsacross the chip was a lab-on-a-chipbefore its time. i-STAT was acquired byAbbott Point-of-Care in 1999 and is nowdistributed globally. Although thei-STAT system initially only measuredphysiological parameters, such as pH,salt, and O2 concentration, it nowcomprises 25 different tests, includingprotein immunoassays for Troponin Iand a cardiac biomarker (measured injust 10 min with a 20 pg ml21 limit-of-detection). In 2002 Lauks founded a

aBiomedical Engineering Department, Genome Quebec

Innovation Centre and Department of Neurology and

Neurosurgery, McGill University, Montreal, Canada.

E-mail: david.juncker@mcgill.cabDepartment of Chemistry, University of Toronto, 80

St. George St., Toronto, ON M5S 3H6, Canada.

E-mail: aaron.wheeler@utoronto.cacInstitute for Sustainable Energy and Department of

Mechanical and Industrial Engineering, University of

Toronto, 5 King’s College Rd., Toronto, ON M5S3G8,

Canada. E-mail: sinton@mie.utoronto.ca

David Juncker is an AssociateProfessor in the BiomedicalEngineering Department ofMcGill University and a principalinvestigator at the McGillUniversity and Genome QuebecInnovation Centre. He holds aCanada Research Chair inMicro- and Nanobioengineering.His current interest is the explora-tion of miniaturization and inte-gration in biology and medicine,including capillary microfluidicson chips and threads for point-of-

care diagnosis, novel antibody microarrays formats and chip-based liquid manipulation for biomarker discovery and valida-tion, as well as 2D and 3D tissue engineering.

Aaron Wheeler is an AssociateProfessor in the Department ofChemistry and in the Institute forBiomaterials and BiomedicalEngineering at the University ofToronto, where he holds theCanada Research Chair inBioanalytical Chemistry. Hisresearch interests are broad, witha focus on the development ofmicrofluidic techniques for clini-cal sample handling and proces-sing and for cell culture andanalysis.

David Juncker Aaron R. Wheeler

Lab on a Chip

EDITORIAL

2438 | Lab Chip, 2013, 13, 2438–2440 This journal is � The Royal Society of Chemistry 2013

second point-of-care company calledEpocal, which was recently acquired byAlere in another multimillion dollardeal. Canada also hosts Edmonton-based Micralyne Inc., one of the firstglobal leaders in commercial microflui-dic chip fabrication. Their ‘standard’microfluidic-cross glass chips wereindeed a mainstay of many researchprograms in the early 2000s, andMicralyne continues as a stalwart ofmicrofluidic instrumentation andMEMS technologies.

This Canadian special issue bringstogether 24 contributions from acrossthe country, and includes a notableconcentration of young research groupswith exciting new directions. The papersgive a snapshot, both of Canadianefforts and those of the larger field,with a combination of advanced nano-sensing and trapping, process integra-tion for health applications, newfunctionalities for droplet- and paper-based devices, and applications reach-ing beyond analytical chemistry andmedicine into energy and the environ-ment.

The diversification of microfluidics isapparent from these Canadian contribu-tions. There are contributions on elec-trokinetics and on-chip valving, whichwere the focus of the early micro-TotalAnalysis Systems community, but withnew twists. Many of the major micro-fluidic areas are covered, includingdroplet-, digital- CD- and PDMS- andpaper-based microfluidics, but alsoemerging areas, such as plantmechanics, microfluidic batteries, saltprecipitation, gas-oil bubbles, and a

lung-assist device, as well as a point-of-care system using modular capillarytubes. Harrison argued that microflui-dics is rooted in the concept of planarnetworks of microscale channels run-ning across chips, and indeed mostmanuscripts conform to this paradigm.However, a number of papers break outof flatland, and into vertical filtration,3D tissue engineering, and even chipsfolded into cones. Finally, a series ofcontributions describe chip-based elec-trochemical and plasmonic sensors andprotein traps. Interestingly, there is alsoa healthy balance between integrationfor practical applications, and the studyof basic phenomena including on-chipgelation, salt precipitation, bubble trap-ping and allosteric effects in enzymeinhibition, reflecting the tremendousflexibility and utility of the lab-on-a-chipapproach.

Canadian scientists have led the wayin the emerging area of nanohole-basedplasmonic sensors. Carlos Escobedofrom Queens University reviews nano-hole array based sensing, detailing thedevelopment of these photonic-turned-fluidic structures and their implicationsfor on-chip sensing (DOI: 10.1039/c3lc50107h). He outlines the optofluidicconcepts and fabrication advances thathave enabled this area, as well as newdirections. The issue also includes twonotable additions in the Canadiannanohole technology narrative.Zehtabi-Oskuie et al. from University ofVictoria describe the optical trappingdynamics of double nanohole struc-tures, and the co-trapping and bindingof individual biomolecules (DOI:

10.1039/c3lc00003f). Tellez et al. fromUniversity of Victoria, University ofOttawa and Carleton University demon-strate highly sensitive refractive indexsensing enabled by atomically flat sym-metric nanohole arrays (DOI: 10.1039/c3lc41411f).

Applications involving cells andmicrofluidics have long been a topic ofinterest for Canadian scientists. Zhenget al. from University of Toronto providea comprehensive review of recentadvances in single-cell biophysical char-acterization (DOI: 10.1039/c3lc50355k).The wide spectrum of microfluidics-based approaches to assessing mechan-ical and electrical properties of livingcells are detailed, as well as futuretechnological opportunities and healthapplications. Lin et al. provide a com-prehensive review of recent develop-ments in microfluidics-basedchemotaxis studies (DOI: 10.1039/c3lc50415h). Advances in exploring cellmigration in controlled chemical gradi-ents are reviewed, as well as chemotaxisin complex environments and high-throughput approaches. Nezhad et al.from Concordia University andUniversite de Montreal present a micro-fluidic approach to the study of themechanical properties of plant cells(DOI: 10.1039/c3lc00012e). Their bend-ing-lab-on-a-chip quantifies the stiffnessof the cell wall of a single pollen tube.Lilge et al. from the University ofToronto approach cell propulsion froman optical perspective, employing radia-tion pressure from end-faced wave-guides integrated on-chip (DOI:10.1039/c3lc41199k). They assess theoptical and geometrical variables influ-encing the motion of leukemia cells.Chen et al. from University of Torontodescribe an ‘‘organ-on-a-chip’’ devicethat is useful for modeling cardiovascu-lar systems (DOI: 10.1039/c3lc00051f).Endothelial cells in one channel werefound to profoundly affect the pheno-type of interstitial cells in a separatechannel (separated by a porous mem-brane), particularly when the endothe-lial cells were exposed to shear stress.Wu et al. from McMaster Universitypresent a chip-based lung assist devicefor newborn infants (DOI: 10.1039/

David Sinton is an Associate Professor in the Departmentof Mechanical and Industrial Engineering, and theDirector of the Institute for Sustainable Energy at theUniversity of Toronto. His research interests are inmicrofluidics for energy applications. Prior to joiningthe University of Toronto, he was an Associate Professorand Canada Research Chair at the University of Victoria,and a Visiting Associate Professor at Cornell University.

David Sinton

This journal is � The Royal Society of Chemistry 2013 Lab Chip, 2013, 13, 2438–2440 | 2439

Lab on a Chip Editorial

c3lc41417e). The porous PDMS micro-fluidic oxygenator provides excellent gasexchange of oxygen and carbon dioxide,and would connect directly to umbilicalvessels. Finally, Shahini and Yeow fromUniversity of Waterloo describe a systemfor on-chip electroporation that makesuse of the unique properties of carbonnanotubes (CNTs) (DOI: 10.1039/c3lc00014a). CNT-modified structuresallow for electroporation at much lowervoltages and with higher efficiency thanthe alternatives.

New device and instrument formatsare also strengths among Canadianscientists. Lam et al. of University ofToronto demonstrate the bottom-upelectrochemical growth of low-cost sen-sors with clinically-relevant levels ofsensitivity and specificity (DOI:10.1039/c3lc41416g). Intricate 3D elec-trode structures were grown here onglass, substantially reducing cost with-out sacrificing performance. Oskooeiet al. from the University of Torontoreport the development of a microflui-dic microvalve enabled by fine controlover gas bubbles (DOI: 10.1039/c3lc50075f). Excellent scalability wasdemonstrated via a network of 128valves, which were used to generatespatial patterns of particular‘‘Canadian’’ interest. The work ofManage et al. brings together research-ers from the University of Alberta, anAlberta Provincial Laboratory for PublicHealth, Aquila Diagnostics Inc., andWestern University (DOI: 10.1039/c3lc41419a) in the development of aself-contained disposable and inexpen-sive gel capillary cassette for DNAamplification. Targeting point-of-careapplications, the PCR reagents aredesiccated and stable for months, priorto rehydration with a raw sample, withtest results from multiple patients inunder an hour. Kirby et al. fromUniversity of Toronto put a new twiston digital microfluidics (DOI: 10.1039/c3lc41431k). In developing a roll-updevice they link the sample handling

advantages of digital microfluidics-based synthesis to the analytical cap-abilities of mass spectrometry (ms). Liet al. from McGill bring valve function-ality to paper-based microfluidics (DOI:10.1039/c3lc00006k). A fluid-triggeredelectromagnetic circuit engages a paperbridge, accommodating automated pro-tocols for multi-step assays in paper. Liet al. from Western University presentan electrochemical lab-on-a-CD devicefor parallel whole blood analysis (DOI:10.1039/c3lc00020f). By incorporatingsimple blood separation and electroche-mical detection, glucose, lactate anduric acids are quantified from 16 mLwhole blood samples in minutes.Tamanna et al. from York Universitypresent electrospray ms-coupled micro-fluidics for protein structural analysisusing rapid hydrogen/deuteriumexchange pulse labelling (DOI: 10.1039/c3lc00007a). Hua et al. from theUniversity of Alberta and the NationalResearch Council present a multichan-nel sample pretreatment device withsheath flow-assisted electrokineticpumping (DOI: 10.1039/c3lc50401h).Their approach enables multiple frac-tionation beds leading to a single down-stream analysis channel as required forintegrated fractionation and proteomicanalysis.

Chemically functionalized particlesare also a hot topic among Canadianscientists with expertise in materials.Wang et al. from University of Torontoexplore a direct injection method ofgenerating polymer microgels in micro-fluidics (DOI: 10.1039/c3lc41385c). Byseparating emulsification and subse-quent gelation unit operations, thisapproach expands the range of accessi-ble gel constituents, most notably toinclude highly viscous polymer solu-tions. Didar et al. from McGillUniversity and the National ResearchCouncil present a particle sortingmethod based on a fully thermoplasticmultilayer device with polycarbonatemembrane filters (DOI: 10.1039/

c3lc50181g). Tuning via integratedpneumatic peristaltic pumps and valvesenables separation of a range of micro-and nanoparticles, as well as cells.

Three papers showcase the potentialof lab-on-a-chip devices in energy, tar-geting oil recovery, energy storage, andthe mitigation of carbon dioxide emis-sions. Fisher et al. from theSchlumberger DBR Technology Centerin Edmonton present a microfluidicapproach to measuring equilibriumgas-oil-ratios of reservoir fluids (DOI:10.1039/c3lc00013c). The microfluidictechnique offers several improvementsover conventional methods for measure-ments central to oil recovery operations.Lee et al. of Simon Fraser Universitydeveloped a membraneless microfluidicredox battery (DOI: 10.1039/c3lc50499a).Dual-pass flow-through porous electro-des enable efficient charging and dis-charging in a compact unit. Kim et al. ofUniversity of Toronto present the aqui-fer-on-a-chip concept providing a pore-scale view of carbon sequestration – agreen house gas mitigation strategy.Pore-scale quantification shows twodominant forms of salt precipitationduring CO2 injection into deep subsur-face saline aquifers (DOI: 10.1039/c3lc00031a).

We thank Lab on a Chip for thisspecial issue and their editorial support,and we thank the lab-on-a-chip commu-nity and all our contributors for a greatsample of Canadian efforts. We thankAndrea Kirby and Thomas de Haas forgenerating the distinctly Canadian coverart, and perhaps most importantly, weacknowledge two decades of support formicrofluidics and lab-on-a-chipresearch from the Canadian governmentthrough the Natural Sciences andEngineering Research Council ofCanada (NSERC) and the CanadianInstitutes for Health Research (CIHR).Thank you for enabling Canadian excel-lence in this area; you put the Canada inlab-on-a-chip.

2440 | Lab Chip, 2013, 13, 2438–2440 This journal is � The Royal Society of Chemistry 2013

Editorial Lab on a Chip