Fabrication and testing of microfluidic devices for blood cell separation

This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.Blood separation is a strategic preliminary step in preparation to on-chip biological analysis. Two microfluidic devices for on-chip blood separation are presented. Both devices will be integrated to form the separation module of a Lab on Chip for non-invasive prenatal diagnosis. In the first device, a blood plasma separator, the separation of blood cells from plasma is made possible in microchannels by bio-physical effects such as an axial migration effect and Zweifach-Fung bifurcation law. Behaviour of mussel and human blood suspensions were studied alongside the effect of different geometries. The second device aims to separate fetal nucleated red blood cells based on their magnetic susceptibility. Biocompatible materials are used in the manufacturing of both devices.The authors acknowledge the financial support of the Engineering and Physical Science Research Council (EPSRC) through the funding of the Grand Challenge Project ‘3DMintegration’, reference EP/C534212/1. This work has also been supported by the EPSRC through a Doctoral Training Account (DTA) and has been performed at the Microsystems Engineering Centre (MISEC), Heriot-Watt University, Edinburgh. We thank Tim Ryan and Phil Summersgill, Epigem Ltd. for the fabrication of the blood plasma chips. The fabrication work was carried out in the Fluence Microfluidics Application Centre supported by the DTI and the OneNE Regional Development Agency as part of the UK's MNT Network

Advances in Microfluidics and Lab-on-a-Chip Technologies

Advances in molecular biology are enabling rapid and efficient analyses for effective intervention in domains such as biology research, infectious disease management, food safety, and biodefense. The emergence of microfluidics and nanotechnologies has enabled both new capabilities and instrument sizes practical for point-of-care. It has also introduced new functionality, enhanced sensitivity, and reduced the time and cost involved in conventional molecular diagnostic techniques. This chapter reviews the application of microfluidics for molecular diagnostics methods such as nucleic acid amplification, next-generation sequencing, high resolution melting analysis, cytogenetics, protein detection and analysis, and cell sorting. We also review microfluidic sample preparation platforms applied to molecular diagnostics and targeted to sample-in, answer-out capabilities

Reusable Ionogel-based Photo-actuators in a Lab-on-a-disc

This paper describes the design, fabrication and performance of a reusable ionogel-based photo-actuator, in-situ photopolymerised into a lab-on-a-disc microfluidic device, for flow control. The ionogel provides an effective barrier to liquids during storage of reagents and spinning of the disc. A simple LED (white light) triggers actuation of the ionogel for selective and precise channel opening at a desired location and time. The mechanism of actuation is reversible, and regeneration of the actuator is possible with an acid chloride solution. In order to achieve regeneration, the Lab-on-a-Disc device was designed with a microchannel connected perpendicularly to the bottom of the ionogel actuator (regeneration channel). This configuration allows the acid solution to reach the actuator, independently from the main channel, which initiates ionogel swelling and main channel closure, and thereby enables reusability of the whole device.Economía y Competitividad), Spain. This project has receivedfunding from the European Union Seventh Framework Programme(FP7) for Research, Technological Development and Demonstrationunder grant agreement no. 604241. JS and FBL acknowledge fund-ing support from Gobierno de Espa˜na, Ministerio de Economía yCompetitividad, with Grant No. BIO2016-80417-P and personallyacknowledge to Marian M. De Pancorbo for letting them to use herlaboratory facilities at UPV/EHU. A.T., L.F., and D.D. are grateful forfinancial support from the Marie Curie Innovative Training Net-work OrgBIO (Marie Curie ITN, GA607896) and Science FoundationIreland (SFI) under the Insight Centre for Data Analytics initiative,Grant Number SFI/12/RC/2289

Integrating microfluidics and biosensing on a single flexible acoustic device using hybrid modes

Integration of microfluidics and biosensing functionalities on a single device holds promise in continuous health monitoring and disease diagnosis for point-of-care applications. However, the required functions of fluid handling and biomolecular sensing usually arise from different actuation mechanisms. In this work, we demonstrate that a single acoustofluidic device, based on a flexible thin film platform, is able to generate hybrid waves modes, which can be used for fluidic actuation (Lamb waves) and biosensing (thickness shear waves). On this integrated platform, we show multiple and sequential functions of mixing, transport and disposal of liquid volumes using Lamb waves, whilst the thickness bulk shear waves allow us to sense the chemotherapeutic Imatinib, using an aptamer-based strategy, as would be required for therapy monitoring. Upon binding, the conformation of the aptamer results in a change in coupled mass, which has been detected. This platform architecture has the potential to generate a wide range of simple sample-to-answer biosensing acoustofluidic devices

Design, test and biological validation of microfluidic systems for blood plasma separation

Sample preparation has been described as the weak link in microfluidics. In particular, plasma has to be extracted from whole blood for many analysis including protein analysis, cell-free DNA detection for prenatal diagnosis and transplant monitoring. The lack of suitable devices to perform the separation at the microscale means that Lab On Chip (LOC) modules cannot be fully operated without sample preparation in a full-scale laboratory. In order to address this issue, blood flow in microchannels has been studied, and red blood cells behaviours in different geometrical environments have been classified. Several designs have been subsequently proposed to exploit some natural properties of blood flow and extract pure plasma without disturbing the cells. Furthermore, a high-level modelling method was developed to predict the behaviour of passive microfluidic networks. Additionally, the technique proposed provides useful guidance over the use of systems in more complex external environments. Experimental results have shown that plasma could be separated from undiluted whole blood in 10μm width microchannels at a flow rate of 2mL/hr. Using slightly larger structures (20μm) suitable for mass-manufacturing, diluted blood can be separated with 100% purity efficiency at high flow rate. An extensive biological validation of the extracted plasma was carried out to demonstrate its quality. To this effect Polymerase Chain Reaction (PCR) was performed to amplify targeted human genomic sequence from cell-free DNA present in the plasma. Furthermore, the influence of the sample dilution and separation efficiency on the amplification was characterised. It was shown that the sample dilution does have an influence on the amplification of house-keeping gene, but that amplification can be achieved even on high diluted samples. Additionally amplification can also be obtained on plasma samples with a range of separation efficiencies from 100% to 84%. In particular, two main points have been demonstrated (i) the extraction of plasma using combination of constrictions and bifurcations, (ii) the biological validation of the extracted plasma

MakerFluidics: low cost microfluidics for synthetic biology

Recent advancements in multilayer, multicellular, genetic logic circuits often rely on manual intervention throughout the computation cycle and orthogonal signals for each chemical “wire”. These constraints can prevent genetic circuits from scaling. Microfluidic devices can be used to mitigate these constraints. However, continuous-flow microfluidics are largely designed through artisanal processes involving hand-drawing features and accomplishing design rule checks visually: processes that are also inextensible. Additionally, continuous-flow microfluidic routing is only a consideration during chip design and, once built, the routing structure becomes “frozen in silicon,” or for many microfluidic chips “frozen in polydimethylsiloxane (PDMS)”; any changes to fluid routing often require an entirely new device and control infrastructure. The cost of fabricating and controlling a new device is high in terms of time and money; attempts to reduce one cost measure are, generally, paid through increases in the other. This work has three main thrusts: to create a microfluidic fabrication framework, called MakerFluidics, that lowers the barrier to entry for designing and fabricating microfluidics in a manner amenable to automation; to prove this methodology can design, fabricate, and control complex and novel microfluidic devices; and to demonstrate the methodology can be used to solve biologically-relevant problems. Utilizing accessible technologies, rapid prototyping, and scalable design practices, the MakerFluidics framework has demonstrated its ability to design, fabricate and control novel, complex and scalable microfludic devices. This was proven through the development of a reconfigurable, continuous-flow routing fabric driven by a modular, scalable primitive called a transposer. In addition to creating complex microfluidic networks, MakerFluidics was deployed in support of cutting-edge, application-focused research at the Charles Stark Draper Laboratory. Informed by a design of experiments approach using the parametric rapid prototyping capabilities made possible by MakerFluidics, a plastic blood--bacteria separation device was optimized, demonstrating that the new device geometry can separate bacteria from blood while operating at 275% greater flow rate as well as reduce the power requirement by 82% for equivalent separation performance when compared to the state of the art. Ultimately, MakerFluidics demonstrated the ability to design, fabricate, and control complex and practical microfluidic devices while lowering the barrier to entry to continuous-flow microfluidics, thus democratizing cutting edge technology beyond a handful of well-resourced and specialized labs