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1 – 10 of 500Dennis Patrick Webb, Benedikt Knauf, Chanqing Liu, David Hutt and Paul Conway
Microfluidic or “lab‐on‐a‐chip” technology is seen as a key enabler in the rapidly expanding market for medical point‐of‐care and other kinds of portable diagnostic device. The…
Abstract
Purpose
Microfluidic or “lab‐on‐a‐chip” technology is seen as a key enabler in the rapidly expanding market for medical point‐of‐care and other kinds of portable diagnostic device. The purpose of this paper is to discuss two proposed packaging processes for large‐scale manufacture of microfluidic systems.
Design/methodology/approach
In the first packaging process, polymer overmoulding of a microfluidic chip is used to form a fluidic manifold integrated with the device in a single step. The anticipated advantages of the proposed method of packaging are ease of assembly and low part count. The second process involves the use of low‐frequency induction heating (LFIH) for the sealing of polymer microfluidics. The method requires no chamber, and provides fast and selective heating to the interface to be joined.
Findings
Initial work with glass microfluidics demonstrates feasibility for overmoulding through two separate sealing principles. One uses the overmould as a physical support structure and providing sealing using a compliant ferrule. The other relies on adhesion between the material of the overmould and the microfluidic device to provide a seal. As regards LFIH work on selection and structuring of susceptor materials is reported, together with analysis of the dimensions of the heat‐affected zone. Acrylic plates are joined using a thin (<10 μm) nickel susceptor providing a fluid seal that withstands a pressure of 590 kPa.
Originality/value
Microfluidic chips have until now been produced in relatively small numbers. To scale‐up from laboratory systems to the production volumes required for mass markets, packaging methods need to be adapted to mass manufacture.
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Amin TermehYousefi, Samira Bagheri and Nahrizul Adib
Biotechnology is closely associated to microfluidics. During the last decade, designs of microfluidic devices such as geometries and scales have been modified and improved…
Abstract
Purpose
Biotechnology is closely associated to microfluidics. During the last decade, designs of microfluidic devices such as geometries and scales have been modified and improved according to the applications for better performance. Numerous sensor technologies existing in the industry has potential use for clinical applications. Fabrication techniques of microfluidics initially rooted from the electromechanical systems (EMS) technology.
Design/methodology/approach
In this review, we emphasized on the most available manufacture approaches to fabricate microchannels, their applications and the properties which make them unique components in biological studies.
Findings
Major fundamental and technological advances demonstrate the enhancing of capabilities and improving the reliability of biosensors based on microfluidic. Several researchers have been reported verity of methods to fabricate different devices based on EMS technology due to the electroconductivity properties and their small size of them. Therefore, controlled fabrication method of MEMS plays an important role to design and fabricate a highly selective detection of medical devices in a variety of biological fluids. Stable, tight and reliable monitoring devices for biological components still remains a massive challenge and several studies focused on MEMS to fabricate simple and easy monitoring devices.
Originality/value
This paper is not submitted or under review in any other journal.
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Darko Belavic, Andraž Bradeško and Hana Uršič
The purpose of this study is to design, fabricate and investigate low-temperature co-fired ceramic (LTCC) structures with integrated microfluidic elements. Special attention is…
Abstract
Purpose
The purpose of this study is to design, fabricate and investigate low-temperature co-fired ceramic (LTCC) structures with integrated microfluidic elements. Special attention is paid to the study of fluid properties of micro-channels and microvalves, which are important constitutive parts of both, microfluidic systems and individual microfluidic devices.
Design/methodology/approach
Several test patterns of fluid channels with different geometry and different types of valves were designed and realized in LTCC technology. All test structures were tested under the flow of two fluids (liquids): water and isopropyl alcohol. Flow rates at different applied pressure were measured and hydrodynamic resistance and diode effect were calculated.
Findings
The investigation of the channels showed that viscosity of fluidic media has significant influence on the hydrodynamic resistance in channels with rectangular cross-section, while this effect is small on channels with square cross-section. The viscosity also has a decisive influence on the diode effect of different shape of valves, and therefore, it is important in the selection of the valve in practical applications.
Research limitations/implications
In this work, the investigation of hydrodynamic resistance of channels and diode effect of passive valves is limited on selected geometry and only on two fluidic media and two applied pressures. All these and some other parameters have a significant influence on fluidic properties, but this will be the topic of the next research work, which will be supported by numerical modelling.
Practical implications
The presented results are useful in the future designing process of LTCC-based microfluidic devices and systems.
Originality/value
Microfluidic in the LTCC structures is an unconventional use of this technology. Therefore, the fluid properties are relatively unsearched. On the other hand, the global use of microfluidic devices and systems is growing rapidly in various applications. They are mostly made by polymer materials, however, in more demanding applications; ceramic is a useful alternative.
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Majid Monajjemi and Fatemeh Mollaamin
Recently, powerful instruments for biomedical engineering research studies, including disease modeling, drug designing and nano-drug delivering, have been extremely investigated…
Abstract
Purpose
Recently, powerful instruments for biomedical engineering research studies, including disease modeling, drug designing and nano-drug delivering, have been extremely investigated by researchers. Particularly, investigation in various microfluidics techniques and novel biomedical approaches for microfluidic-based substrate have progressed in recent years, and therefore, various cell culture platforms have been manufactured for these types of approaches. These microinstruments, known as tissue chip platforms, mimic in vivo living tissue and exhibit more physiologically similar vitro models of human tissues. Using lab-on-a-chip technologies in vitro cell culturing quickly caused in optimized systems of tissues compared to static culture. These chipsets prepare cell culture media to mimic physiological reactions and behaviors.
Design/methodology/approach
The authors used the application of lab chip instruments as a versatile tool for point of health-care (PHC) applications, and the authors applied a current progress in various platforms toward biochip DNA sensors as an alternative to the general bio electrochemical sensors. Basically, optical sensing is related to the intercalation between glass surfaces containing biomolecules with fluorescence and, subsequently, its reflected light that arises from the characteristics of the chemical agents. Recently, various techniques using optical fiber have progressed significantly, and researchers apply highlighted remarks and future perspectives of these kinds of platforms for PHC applications.
Findings
The authors assembled several microfluidic chips through cell culture and immune-fluorescent, as well as using microscopy measurement and image analysis for RNA sequencing. By this work, several chip assemblies were fabricated, and the application of the fluidic routing mechanism enables us to provide chip-to-chip communication with a variety of tissue-on-a-chip. By lab-on-a-chip techniques, the authors exhibited that coating the cell membrane via poly-dopamine and collagen was the best cell membrane coating due to the monolayer growth and differentiation of the cell types during the differentiation period. The authors found the artificial membrane, through coating with Collagen-A, has improved the growth of mouse podocytes cells-5 compared with the fibronectin-coated membrane.
Originality/value
The authors could distinguish the differences across the patient cohort when they used a collagen-coated microfluidic chip. For instance, von Willebrand factor, a blood glycoprotein that promotes hemostasis, can be identified and measured through these type-coated microfluidic chips.
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Keryn Lian, Shawn O'Rourke, Daniel Sadler, Claudia Gamboa, Robert Terbrueggen and Marc Chason
The purpose of this paper is to present the development of printed wiring board (PWB)‐based microfluidic building blocks and their integration into systems for DNA amplification…
Abstract
Purpose
The purpose of this paper is to present the development of printed wiring board (PWB)‐based microfluidic building blocks and their integration into systems for DNA amplification and electronic detection.
Design/methodology/approach
Technologies from embedded passives (EP) and photolithographic high‐density interconnect are integrated into a traditional PWB platform to enable multifunctional electrochemical sensors for on‐chip detection of biological assays.
Findings
PWB materials and processes can be applied to develop microelectromechanical systems (MEMS) and microfluidic systems. On‐chip heaters using EP have been demonstrated with excellent accuracy. The on‐chip heaters can be used for localized temperature control as well as heat air pumps. The integration of EP and microchannels is a promising approach to add functionalities to the PWB‐based microsystems.
Research limitations/implications
Further integration of microchannels with the embedded heaters and electrochemical sensors will increase the compactness, functionality, and value of the PWB‐based microfluidic systems.
Originality/value
The paper describes the development and integration of PWB‐based building‐blocks such as EP and microchannels for MEMS and microfluidic applications. These elements will enable new applications and enhanced functionalities of PWB.
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Reza Hadjiaghaie Vafaie, Hossein Dehganpour and Abolfazl Moradpour
Digital microfluidic devices have been demonstrated to have great potential for a wide range of applications. These devices need expensive photolithography process and clean room…
Abstract
Purpose
Digital microfluidic devices have been demonstrated to have great potential for a wide range of applications. These devices need expensive photolithography process and clean room facilities, while printed circuit board (PCB) technology provides high configurability and at low cost. This study aims to investigate the mechanism of electrowetting-on-a-dielectric (EWOD) on PCB by solving the multiphysics interaction between fluid droplet and electric field. The performance of system will be improved by inducing an efficient electric field inside the droplet.
Design/methodology/approach
To induce an electric field inside the droplet on a PCB and change the initial contact angle, the mechanism of EWOD is studied based on energy minimization method and a set of simulations are carried out by considering multiphysics interaction between the fluid droplet and external electric field. The performance of EWOD on a PCB system is investigated using different electrode structures.
Findings
Surface tension plays an efficient role in smaller sizes and can be used to move and control a fluid droplet on a surface by changing the interfacial surface tension. EWOD on a PCB system is studied. and it revealed that any change in electric field affects the droplet contact angle and as a result droplet deformation and movement. The electrode pattern is an important parameter which could change the electric potential distribution inside the droplet. Array of electrodes with square, zigzag interdigitated and crescent shapes are studied to enhance the EWOD force on a PCB substrate. Based on the results, the radial shape of the crescent electrodes keeps almost the same actuated contact line, applies uniform force on the droplet periphery and prevents the droplet from large deformation. A droplet velocity of 0.6 mm/s is achieved by exciting the crescent electrodes at 315 V. Furthermore, the behavior of system is characterized for process parameters such as actuation voltage, dielectric constant of insulator layer, fluidic material properties and the resultant velocity and contact angle. The study of contact angle distribution and droplet motion revealed that it is helpful to generate EWOD mechanism on a PCB which does not need more complicated fabrication processes.
Originality/value
The ability to handle and manipulate the droplets is very important for chemistry on-chip analysis such as immunoassay chips. Furthermore, a PCB-based electrowetting-on-dielectric device is of high interest because it does not need cleanroom facilities and avoids additional high-cost fabrication processes. In the present research, the EWOD mechanism is studied on a PCB by using different electrode patterns.
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P.S. Maher, R.P. Keatch and K. Donnelly
The area of microfluidic systems has greatly enhanced the in vitro field of tissue engineering. Microfluidic systems such as microchannelled assays are now widely used for…
Abstract
Purpose
The area of microfluidic systems has greatly enhanced the in vitro field of tissue engineering. Microfluidic systems such as microchannelled assays are now widely used for mimicking in vivo cell behaviour and studies into basic biological research. In certain cases engineered tissue cell design use 3D ordered geometrical configurations in vitro (such as microchannel assays) to reproduce native in vivo functions. The most common approach for manufacturing micro‐assays is now rapid prototyping (RP) technology. The choice of assay material is dependent on the proposed cell type and ultimately the tissue application. However, many RP technologies can be unsuitable for cell growth applications because of the construction methods and materials they employ. The purpose of this paper is to describe a comparison between two different RP 3D printing methods of fabrication and investigates the merits of each technology for direct cell culture applications using micro‐assays, while also examining the dispensing accuracy of both techniques.
Design/methodology/approach
Using a Thermojet and Spectrum Z510 printer pre‐designed micro‐assays incorporating different size microchannels are dispensed. The base materials of both methods are examined for cytotoxic effects while in solution with primary tendon fibroblasts (PFB) cells. After obtaining favorable results from the toxicology experiments, PFB cells are seeded onto the thermojet structures with a view to investigate cell adherence, encapsulation and how the channel width influences cell alignment.
Findings
This research concluded that the thermojet had a higher degree of accuracy when manufacturing structures that incorporate microchannels when compared with the Spectrum Z510. Both techniques show that the accuracy of the build decreases with reduction in channel width. The fact that the Spectrum Z510 structures have to be infiltrated with a hardening glue as a post‐processing technique (since the dispensed material is water‐based and hence soluble) causes a cytotoxic effect compared to the thermojet plastic which is not cytotoxic in solution with PFB cells. Seeding the PBF cells directly onto the thermoplastic structure caused problems due to the hydrophobic nature of the material and this necessitated the technique of soaking the structures in a collagen bath to penetrate the surface and reduce the interactions of hydrophobic species enhancing cell attachment and proliferation. Without this coating the thermojet structures induced strong hydrophobic interactions at the surfaces of the microchannels with the culture media resulting in non‐attachment and poor cell mortality.
Originality/value
This research paper describes a comparison between the base materials and methodology of two 3D printing techniques for applications in basic biological studies. This is achieved by analysing the dispensing accuracy of both technologies and the interaction between cells and surface at the interface.
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A.K. Abdul Hakeem, Priya S., Ganga Bhose and Sivasankaran Sivanandam
The purpose of this study is to provide that porous media and viscous dissipation are crucial considerations when working with hybrid nanofluids in various applications.Recent…
Abstract
Purpose
The purpose of this study is to provide that porous media and viscous dissipation are crucial considerations when working with hybrid nanofluids in various applications.Recent years have witnessed significant progress in optimizing these fluids for enhanced heat transfer within porous (Darcy–Forchheimer) structures, offering promising solutions for various industries seeking improved thermalmanagement and energy efficiency.
Design/methodology/approach
The first step is to transform the original partial differential equations into a system of first-order ordinary differential equations (ODEs). The fourth-order Runge–Kutta method is chosen for its accuracy in solving ODEs. The present study investigates the free convective boundary layer flow of hybrid nanofluids over a moving thin inclined needle with the slip flow brought about by inclined Lorentz force and Darcy–Forchheimer porous matrix, viscous dissipation.
Findings
It is found that slip conditions (velocity and Thermal) exist for a range of the natural convection boundary layer flow. In the hybrid nanofluid flow, which consists of Al2O3 and Fe3O4 are nanoparticles, H2O − C2H6O2 (50:50) are considered as the base fluid. The consequence of the governing parameter on the momentum and temperature profile distribution is graphically depicted. The range of the variables is 1 ≤ M ≤ 4, 1 ≤ d ≤ 2.5, 1 ≤ δ ≤ 4, 1 ≤ Fr ≤ 7, 1 ≤ Kr ≤ 7 and 0.5≤λ ≤ 3.5. The Nusselt number and skin friction factors are used to calculate the numerical values of various parameters, which are displayed in Table 4. These analyses elucidate that upsurges in the value of the Fr noticeably diminish the momentum and temperature. It is investigated to see if the contemporary results are in outstanding promise with the outcomes reported in earlier works.
Practical implications
The results can be very helpful to improve the energy efficiency of thermal systems.
Social implications
The hybrid nanofluids in heat transfer have the potential to improve the energy efficiency and performance of a wide range of systems.
Originality/value
This study proposes that in the combined effects of hybrid nanofluid properties, the inclined Lorentz force, the Darcy–Forchheimer model for porous media and viscous dissipation on the boundary layer flow of a conducting fluid over a moving thin inclined needle. Assessing the potential practical applications of the hybrid nanofluids in inclined needles, this could involve areas such as biomedical engineering, drug delivery systems or microfluidic devices. In future should explore the benefits and limitations of using hybrid nanofluids in these applications.
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Jinwei Zhao, Shuolei Feng, Xiaodong Cao and Haopei Zheng
This paper aims to concentrate on recent innovations in flexible wearable sensor technology tailored for monitoring vital signals within the contexts of wearable sensors and…
Abstract
Purpose
This paper aims to concentrate on recent innovations in flexible wearable sensor technology tailored for monitoring vital signals within the contexts of wearable sensors and systems developed specifically for monitoring health and fitness metrics.
Design/methodology/approach
In recent decades, wearable sensors for monitoring vital signals in sports and health have advanced greatly. Vital signals include electrocardiogram, electroencephalogram, electromyography, inertial data, body motions, cardiac rate and bodily fluids like blood and sweating, making them a good choice for sensing devices.
Findings
This report reviewed reputable journal articles on wearable sensors for vital signal monitoring, focusing on multimode and integrated multi-dimensional capabilities like structure, accuracy and nature of the devices, which may offer a more versatile and comprehensive solution.
Originality/value
The paper provides essential information on the present obstacles and challenges in this domain and provide a glimpse into the future directions of wearable sensors for the detection of these crucial signals. Importantly, it is evident that the integration of modern fabricating techniques, stretchable electronic devices, the Internet of Things and the application of artificial intelligence algorithms has significantly improved the capacity to efficiently monitor and leverage these signals for human health monitoring, including disease prediction.
Fabio Mota, Luiza Amara Maciel Braga, Bernardo Pereira Pereira Cabral and Carlos Gilbert Conte Filho
Lab on-a-chip (LOC) may lead to low-cost point-of-care devices for the diagnosis of human diseases, possibly making laboratories dispensable. However, as it is still an emerging…
Abstract
Purpose
Lab on-a-chip (LOC) may lead to low-cost point-of-care devices for the diagnosis of human diseases, possibly making laboratories dispensable. However, as it is still an emerging technology, very little is known about its future impact on the diagnosis of human diseases, and on the laboratory industry. Hence, the purpose of this study is to foresee possible developments of this technology through a consultation with researchers in the field in two distinct time periods.
Design/methodology/approach
Based on Technology Foresight, this study addresses this gap by assessing the opinions of over five hundred LOC researchers and tracking changes in their views on the future of LOC diagnostic devices. These researchers participated in a two-wave global survey with an interval of two and a half years
Findings
Although second-wave (2020) respondents are less optimistic than those of the first wave (2017), the results of both surveys show that LOC diagnostic devices are expected to: move from proof-of-concept demonstrations to industrial development, becoming commercially feasible worldwide; integrate all laboratory processes, delivering cheaper, faster and more reliable diagnoses than laboratories; and provide low-cost point-of-care solutions, improving access to healthcare.
Research limitations/implications
Although it would be desirable to collect and explore the views of different sets of stakeholders, the method of generating lists of survey respondents shows a bias toward academic/scientific circles because the respondents are authors of scientific publications. These publications may as well be authored by stakeholders from other fields but it is reasonable to assume that most of them are researchers affiliated with universities and research and development organizations. Therefore, this study lacks in providing an image of the future based on a more diverse set of respondents.
Social implications
The results show that these devices are expected to radically change the diagnostic testing market and the way laboratories are organized, perhaps moving to a non-laboratory-based model. In conclusion, in the coming decades, these devices may promote substantial changes in the way human diseases are diagnosed.
Originality/value
Only a few studies have attempted to foresee the future of LOC devices, and most are based on literature reviews. Thus, this study goes beyond the existing research by providing a broad understanding of what the future will look like from the views of researchers who are contributing to the advancement of knowledge in the field. The researchers invited to take part in this study are authors of LOC-related scientific publications indexed in the Web of Science Core Collection.
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