Rapid prototyping of microfluidic devices with integrated wrinkled gold micro-/nano textured electrodes for electrochemical analysis

The Analyst ◽  
2015 ◽  
Vol 140 (16) ◽  
pp. 5781-5788 ◽  
Author(s):  
C. M. Gabardo ◽  
R. C. Adams-McGavin ◽  
O. M. Vanderfleet ◽  
L. Soleymani
Keyword(s):  
Rapid Prototyping ◽  
Environmental Monitoring ◽  
Biological Sample ◽  
Lab On A Chip ◽  
Microfluidic Devices ◽  
Electrochemical Analysis ◽  
Sample Processing ◽  
Fully Integrated ◽  
Nano Scale ◽  
Wide Range

Fully-integrated electro-fluidic systems with micro-/nano-scale features have a wide range of applications in lab-on-a-chip systems used for biosensing, biological sample processing, and environmental monitoring.

Rapid Prototyping of PDMS Devices With Applications to Protein Crystallization

2007 ◽  
Author(s):  
Walter Gonzalez-Domenzain ◽  
Ashwin A. Seshia
Keyword(s):  
Rapid Prototyping ◽  
Protein Crystallization ◽  
Three Dimensional ◽  
Vertical Channel ◽  
Microfluidic Devices ◽  
Sample Processing ◽  
Channel Geometry ◽  
Parallel Sample ◽  
Ink Jet ◽  
Reaction Volumes

This paper describes a microfabrication process for constructing three-dimensional microfluidic structures in polydimethylsiloxane (PDMS). Rapid prototyping of microfluidic devices is possible starting from ink-jet printed masks and by utilising replica molding to create fluidic structures in PDMS from SU-8 and SPR-220 masters pre-patterned on a silicon or glass substrate. Multi-layer bonded and stacked alignment of up to 13 different functional polymer microfluidic layers with through-layer fluidic interconnects has been demonstrated. Pneumatically actuated valves have also been demonstrated for the regulation of sub-10 nL of fluid volumes. The geometric design of the valves is described with experimental verification conducted on rounded and vertical channel profiles to examine the effects of channel geometry on valve leak rates. The PDMS-based technology allows for the fabrication of devices with extremely small reaction volumes and parallel sample processing, making these devices ideally suited to applications which require high throughput processing and the ability to conduct parallel assays with very limited volumes of reagent and sample. We describe the applications of this technology to protein crystallization in particular.

scholarly journals A cost-effective micromilling platform for rapid prototyping of microdevices

TECHNOLOGY ◽  
2016 ◽  
Vol 04 (04) ◽  
pp. 234-239 ◽  
Author(s):  
Daniel P. Yen ◽  
Yuta Ando ◽  
Keyue Shen
Keyword(s):  
Rapid Prototyping ◽  
Low Cost ◽  
Lab On A Chip ◽  
Microfluidic Devices ◽  
Cost Effective ◽  
Multi Scale ◽  
Organ On A Chip

Micromilling has great potential in producing microdevices for lab-on-a-chip and organ-on-a-chip applications, but has remained under-utilized due to the high machinery costs and limited accessibility. In this paper, we assessed the machining capabilities of a low-cost 3-D mill in polycarbonate material, which were showcased by the production of microfluidic devices. The study demonstrates that this particular mill is well suited for the fabrication of multi-scale microdevices with feature sizes from micrometers to centimeters.

To the 70th anniversary of World Meteorological Organization. Scientific and technical cooperation of Hydrometeorological Center of the USSR/Russia in the Programs of World Meteorological Organization

2020 ◽  
pp. 117-138
Author(s):  
S.V. Borshch ◽  
◽  
R.M. Vil’fand ◽  
D.B. Kiktev ◽  
V.M. Khan ◽  
...  
Keyword(s):  
Environmental Monitoring ◽  
High Efficiency ◽  
World Meteorological Organization ◽  
70Th Anniversary ◽  
Technical Level ◽  
Technical Cooperation ◽  
Wide Range

The paper presents the summary and results of long-term and multi-faceted experience of international scientific and technical cooperation of Hydrometeorological Center of Russia in the field of hydrometeorology and environmental monitoring within the framework of WMO programs, which indicates its high efficiency in performing a wide range of works at a high scientific and technical level. Keywords: World Meteorological Organization, major WMO programs, representatives of Hydrometeorological Center of Russia in WMO

scholarly journals Emerging Lab-on-a-Chip Approaches for Liquid Biopsy in Lung Cancer: Status in CTCs and ctDNA Research and Clinical Validation

Cancers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 2101
Author(s):  
Ângela Carvalho ◽  
Gabriela Ferreira ◽  
Duarte Seixas ◽  
Catarina Guimarães-Teixeira ◽  
Rui Henrique ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Liquid Biopsy ◽  
Residual Disease ◽  
Lab On A Chip ◽  
Microfluidic Devices ◽  
Early Recurrence ◽  
Circulating Tumor Dna ◽  
Clinical Validation ◽  
Liquid Biopsies ◽  
Lung Cancer Patients

Despite the intensive efforts dedicated to cancer diagnosis and treatment, lung cancer (LCa) remains the leading cause of cancer-related mortality, worldwide. The poor survival rate among lung cancer patients commonly results from diagnosis at late-stage, limitations in characterizing tumor heterogeneity and the lack of non-invasive tools for detection of residual disease and early recurrence. Henceforth, research on liquid biopsies has been increasingly devoted to overcoming these major limitations and improving management of LCa patients. Liquid biopsy is an emerging field that has evolved significantly in recent years due its minimally invasive nature and potential to assess various disease biomarkers. Several strategies for characterization of circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) have been developed. With the aim of standardizing diagnostic and follow-up practices, microfluidic devices have been introduced to improve biomarkers isolation efficiency and specificity. Nonetheless, implementation of lab-on-a-chip platforms in clinical practice may face some challenges, considering its recent application to liquid biopsies. In this review, recent advances and strategies for the use of liquid biopsies in LCa management are discussed, focusing on high-throughput microfluidic devices applied for CTCs and ctDNA isolation and detection, current clinical validation studies and potential clinical utility.

Integrated Heterogeneous Micro-Nano Systems via Modular Designing and Flexible Assembly

2011 ◽  
Author(s):  
Aditya Das ◽  
Rakesh Murthy
Keyword(s):  
Uncertainty Propagation ◽  
Systems Development ◽  
Surface Machining ◽  
Flexible Assembly ◽  
Nano Scale ◽  
Wide Range ◽  
Standard Design ◽  
Novel Algorithms ◽  
And Control ◽  
Dedicated Hardware

One of the major challenges in commercializable micro-nano systems development is the high cost and turnaround that are incurred through multiple product-optimization iterations and expensive fabrication processes for specific systems. Development of complex and heterogeneous micro-nano systems, that are only possible through assembly and not by conventional surface machining approaches, are further impeded by lack of standard design rules and off-the-shelf robotic manipulation systems. Dedicated hardware and system specific component designs, although possible, are not commercially viable for addressing the wide range of opportunities that exists in the prevailing micro-nano domain. In this paper, we present an alternative and holistic top-down approach for micro-nano manufacturing using modular part designs and flexible assembly systems. We incorporate, seamlessly, multiple novel algorithms related to microrobotics and scaling of physics, obtained both analytically as well as experimentally; in order to predict, track and control the uncertainty propagation in a typical manufacturing process, in micro-nano scale, throughout production steps including design, machining, setup, assembly, testing etc. We demonstrate, through multiple examples, the implementation of the proposed framework in micro-nano scale manufacturing.

scholarly journals Holistic Approach to Design, Test, and Optimize Stand-Alone SOFC-Reformer Systems

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 348
Author(s):  
Michael Höber ◽  
Benjamin Königshofer ◽  
Philipp Wachter ◽  
Gjorgji Nusev ◽  
Pavle Boskoski ◽  
...  
Keyword(s):  
Rural Communities ◽  
High Efficiency ◽  
Diffusion Processes ◽  
Holistic Approach ◽  
Maximum Error ◽  
Gas Diffusion ◽  
Electrochemical Analysis ◽  
Internal Reforming ◽  
Operation Conditions ◽  
Wide Range

Reliable electrical and thermal energy supplies are basic requirements for modern societies and their food supply. Stand-alone stationary power generators based on solid oxide fuel cells (SOFC) represent an attractive solution to the problems of providing the energy required in both rural communities and in rurally-based industries such as those of the agricultural industry. The great advantages of SOFC-based systems are high efficiency and high fuel flexibility. A wide range of commercially available fuels can be used with no or low-effort pre-treatment. In this study, a design process for stand-alone system consisting of a reformer unit and an SOFC-based power generator is presented and tested. An adequate agreement between the measured and simulated values for the gas compositions after a reformer unit is observed with a maximum error of 3 vol% (volume percent). Theoretical degradation free operation conditions determined by employing equilibrium calculations are identified to be steam to carbon ratio (H2O/C) higher 0.6 for auto-thermal reformation and H2O/C higher 1 for internal reforming. The produced gas mixtures are used to fuel large planar electrolyte supported cells (ESC). Current densities up to 500 mA/cm2 at 0.75 V are reached under internal reforming conditions without degradation of the cells anode during the more than 500 h long-term test run. More detailed electrochemical analysis of SOFCs fed with different fuel mixtures showed that major losses are caused by gas diffusion processes.

Οπτικοί βιοαισθητήρες για την ανίχνευση βιομορίων χωρίς τη χρήση ιχνηθετών

2015 ◽  
Author(s):  
Αιμιλία Ψαρούλη
Keyword(s):  
Light Source ◽  
Silicon Substrate ◽  
Serum Samples ◽  
Fully Integrated ◽  
Monolithically Integrated ◽  
Immunochemical Determination ◽  
Wide Range ◽  
Myocardial Infraction ◽  
Biological Recognition

Recent developments in the fields of bioanalytical chemistry and microelectronics have resulted in a growing trend of transferring the classical analytical methods from the laboratory bench to the field through the development of portable devices or microsystems based on biosensors. Biosensors are self-contained integrated devices capable to provide analytical information using biological recognition molecules in direct spatial contact with a transducer. Biosensors using antibodies or antigens as biological recognition elements are termed as immunosensors and they are based on the same principle as the classical solid-phase immunoassays.The aim of this thesis was to develop and evaluate an optical immunosensor based on Mach-Zehnder Interferometry and integrated on silicon substrate for the immunochemical determination of clinical analytes. The optical sensor developed is fabricated entirely by mainstream silicon technology by the Optical Biosensors group of the Institute of Nanoscience and Nanotechnology of NCSR “Demokritos” and combines arrays of ten sensors in a single silicon chip. Each sensor consists of an integrated on silicon light source that emits a broad spectrum in visible-near ultraviolet range and it is coupled to an integrated silicon nitride waveguide which has been patterned into Mach-Zehnder interferometer. The signal is recorded either through a photodetector monolithically integrated onto the same silicon chip (fully integrated configuration) or through an external spectrometer (semi-integrated configuration). In the fully integrated configuration, the signal recorded is the total photocurrent across the whole spectral range, while in semi-integrated configuration the whole transmission spectrum is continuously recorded and is mathematically transformed (Fourier Transform) to phase shift. As in the classical Mach-Zehnder interferometers, the waveguide in the proposed sensor is split into two arms, the sensing one which is appropriately modified with recognition biomolecule and the reference arm that is covered by a protective layer. The specific binding of the analyte with the immobilized onto the surface recognition biomolecule causes an effective refractive index change at the surface of the sensing arm thus affecting the phase of the waveguided light with respect to the reference arm. Thus, when the two arms converge again, an interference spectrum is generated that is altered during bioreaction providing the ability of monitoring in real-time and without using labels. The main difference of the sensor developed with respect to classical Mach-Zehnder interferometers is that the light source is monolithically integrated on the same silicon substrate with the waveguides and the waveguided light is not monochromatic, but broad spectrum.At first in this study, the method for chemical activation of biofunctionalization of chips was optimized. It was found that the highest signals were obtained when chips where activated by (3-aminopropyl)triethoxysilane and deposition of biomolecules solutions using a microarray spotter. Then, a comparison of the two sensor configurations, i.e. the fully and the semi-integrated configuration was performed using a model binding assay namely the streptavidin-biotin reaction. Semi-integrated configuration provided higher detection sensitivities mainly due to lower between-sensor signal variation in the same chip and between different chips. Thus, this configuration was selected for further evaluation with respect to the determination of analytes of clinical interest and especially of immunochemical determination of C-reactive protein in human serum samples. CRP is a marker of inflammation widely used in everyday clinical practice for diagnosis and therapy monitoring of inflammatory situations. Nevertheless, CRP has been also proposed as a prognostic marker of myocardial infraction and three risk levels have been established; low risk for serum CRP concentrations < 1 μg/mL; medium risk for concentrations in the range 1-3 μg/mL; and high risk for concentrations >3 μg/mL. In the frame of the present thesis, enzyme immunoassays for the determination of CRP in microtitration plates both competitive and non-competitive were developed in order to select the most appropriate reagents and define the immunoassay conditions. Then both assay format were transferred and evaluated on the sensor. It was found that the non-competitive format offered higher responses and ability for regeneration of immobilized onto the sensor antibody against CRP and was therefore selected for the final sensor evaluation. The assay developed following the competitive format was sensitive and accurate as was demonstrated through recovery and dilution linearity experiments, and provided for analysis of samples with a wide range of CRP concentrations since it was immune to the presence of serum. In addition, the CRP values determined with the immunosensor developed in serum samples from unknown donors were in good agreement with those determined for the same samples by commercially available kits and instruments showing the reliability of the determinations performed with the immunosensor developed and its potential for analysis of clinical samples.

A fully integrated passive microfluidic Lab-on-a-Chip for real-time electrochemical detection of ammonium: Sewage applications

2019 ◽  
Vol 653 ◽  
pp. 1223-1230 ◽  
Author(s):  
J. Gallardo-Gonzalez ◽  
A. Baraket ◽  
S. Boudjaoui ◽  
T. Metzner ◽  
F. Hauser ◽  
...  
Keyword(s):  
Real Time ◽  
Electrochemical Detection ◽  
Lab On A Chip ◽  
Fully Integrated

Manipulation of Clinical Materials Using AC Electrokinetics

2010 ◽  
Author(s):  
Mandy L. Y. Sin ◽  
Pak Kin Wong
Keyword(s):  
Experimental Data ◽  
Sample Preparation ◽  
Theoretical Prediction ◽  
Fluid Motion ◽  
Lab On A Chip ◽  
Clinical Samples ◽  
Electrochemical Reactions ◽  
Ac Electrokinetics ◽  
Wide Range ◽  
Electrothermal Flow

AC electrokinetics is a promising approach for sample preparation and reaction enhancement in lab-on-a-chip devices. However, relative little has been done on the electrokinetic manipulation of physiological fluids and buffers with similar properties, such as conductivity. Herein, electrokinetic manipulation of fluids with a wide range of conductivities has been studied as a function of voltage and frequency. AC electrothermal flow is determined to dominate the fluid motion when the applied frequency of the AC potential is above 100 kHz. Interestingly, experimental data deviate from theoretical prediction for fluids with high conductivities (> 1 Sm−1). The deviation can be understood by voltage modulated electrochemical reactions and should be accounted for when manipulating clinical materials with high conductivities. The study will provide useful in sights in designing lab-on-a-chip devices for manipulating clinical samples in the future.

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