Microfluidic design for bio-sample delivery to silicon nanowire biosensor - a simulation study
01 Apr 2006-Vol. 34, Iss: 1, pp 626-630
TL;DR: In this article, the authors examined various microfluidic channel designs for sample delivery to silicon nano-wire biosensors pertaining to the modeling and simulation, and established the viability of hydrodynamic focusing through splitting a single flow into two and permitting focusing of bio-samples at the flow recombination region.
Abstract: We examine various microfluidic channel designs for sample delivery to silicon nano-wire biosensors pertaining to the modeling and simulation. Nano-wires with its high sensitivity permits label free detection of bio-molecules. Without careful considerations to its fluidic delivery network, effects of detection can be limited. Different micro-channel designs of relatively larger width aid in fluid release and sensors are placed strategically to attain high efficiency in bio-sample delivery. One design establishes the viability of hydrodynamic focusing through splitting a single flow into two and permits focusing of bio-samples at the flow recombination region. It avoids the delicated fluidic delivery systems generally used in hydrodynamic focusing. A focusing effect of 71.3% based on the movement of a massless particle in the fluid is achieved using a straight channel design with a partition wall inside. Moreover, sample is focused in low velocity region which maintains minimal impact to nanowire sensor. This provides a simple and efficient delivery system for the nano-wire sensor upon integration.
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TL;DR: Aiming to provide a comprehensive roadmap for the development of SiNW FET based sensing platforms, this work critically review and discuss the key design and fabrication aspects relevant to their development and integration within complementary metal-oxide-semiconductor (CMOS) technology.
Abstract: Owing to their two-dimensional confinements, silicon nanowires display remarkable optical, magnetic, and electronic properties. Of special interest has been the development of advanced biosensing approaches based on the field effect associated with silicon nanowires (SiNWs). Recent advancements in top-down fabrication technologies have paved the way to large scale production of high density and quality arrays of SiNW field effect transistor (FETs), a critical step towards their integration in real-life biosensing applications. A key requirement toward the fulfilment of SiNW FETs’ promises in the bioanalytical field is their efficient integration within functional devices. Aiming to provide a comprehensive roadmap for the development of SiNW FET based sensing platforms, we critically review and discuss the key design and fabrication aspects relevant to their development and integration within complementary metal-oxide-semiconductor (CMOS) technology.
81 citations
Cites background from "Microfluidic design for bio-sample ..."
...Such microfluidic design has the advantage of low mechanical influence on the flow velocity while maintaining the hydrodynamic focusing effect [104]....
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01 Sep 2012
TL;DR: In this article, a simulation of fluid flow, the mixing concentration distribution to the interaction of protein and other biological reagents, fluid flow pressure, and fluid flow velocity field with designing Micromixer, Microchannel and Microchamber for Microfluidic devices using simulation software COMSOL Multiphysics 3.5.
Abstract: Microfluidic devices present a unique powerful platform for working with living cells. The length and volume scales of these devices in miniaturize system make it possible to perform detailed analyses with several advantages. The small volume facilitates response detection by effectively increasing the local concentration of the analyte. Microfluidic lab-on-chip technologies represent a revolution in laboratory experimentation, bringing the benefits of miniaturization to many researchers. This project aim on simulation of the fluid flow, the mixing concentration distribution to the interaction of protein and other biological reagents, fluid flow pressure, and fluid flow velocity field with designing Micromixer, Microchannel and Microchamber for Microfluidic devices using simulation software COMSOL Multiphysics 3.5. Fluid flow patterns, concentration distribution and velocity field were observed by using simulation software. Fluid flow patterns obtained at the junction and The component consists of a PDMS microchannel to give a continuous open circuit flow, a 0.7μm/s was obtained.
27 citations
Cites background from "Microfluidic design for bio-sample ..."
...The other two designs produce similar effects (Tan et al, 2006)....
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TL;DR: In this article, the most appealing sensing devices are discussed, starting from electronic transducers, with Si nanowires field effect transistor (FET) and porous Si, to their optical alternatives, such as effective optical thickness porous silicon, photonic crystals, luminescent Si quantum dots, and finally luminecent Si NWs, with a specific focus on the possibility of their industrial transfer and which ones may be preferred for a medical device.
26 citations
TL;DR: In this paper, the microstructure of SiNWs was characterized by field emission scanning electron microscopy (FESEM) and TEM, and it was shown that the SiNW consists of crystalline core silicon surrounded by thick amorphous silicon oxide and the total diameter including the outer SiO2 sheath was 60-80nm.
11 citations
Journal Article•
TL;DR: In this paper, a single atom sensor was used for biological application and the possibility of creating interatomic interaction between sensor and biological species through strong, fundamental and natural force of attraction that exist between the protons of the sensing element and ionic properties of biological species could be used as a source for introduction of natural binding chemistry of electrostatic attraction of the particles to bind biological species on a sensing element.
Abstract: The paper contain a report on proposal to use a single atom sensor for biological application, we are reporting a possibility of creating interatomic interaction between sensor and biological species through strong, fundamental and natural force of attraction that exist between the protons of the sensing element and ionic properties of biological species could be used as a source for introduction of natural binding chemistry of electrostatic attraction of the particles to bind biological species on a sensing element.
9 citations
References
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TL;DR: The small size and capability of these semiconductor nanowires for sensitive, label-free, real-time detection of a wide range of chemical and biological species could be exploited in array-based screening and in vivo diagnostics.
Abstract: Boron-doped silicon nanowires (SiNWs) were used to create highly sensitive, real-time electrically based sensors for biological and chemical species. Amine- and oxide-functionalized SiNWs exhibit pH-dependent conductance that was linear over a large dynamic range and could be understood in terms of the change in surface charge during protonation and deprotonation. Biotin-modified SiNWs were used to detect streptavidin down to at least a picomolar concentration range. In addition, antigen-functionalized SiNWs show reversible antibody binding and concentration-dependent detection in real time. Lastly, detection of the reversible binding of the metabolic indicator Ca2+ was demonstrated. The small size and capability of these semiconductor nanowires for sensitive, label-free, real-time detection of a wide range of chemical and biological species could be exploited in array-based screening and in vivo diagnostics.
5,841 citations
TL;DR: Highly sensitive, label-free, multiplexed electrical detection of cancer markers using silicon-nanowire field-effect devices in which distinct nanowires and surface receptors are incorporated into arrays opens up substantial possibilities for diagnosis and treatment of cancer and other complex diseases.
Abstract: We describe highly sensitive, label-free, multiplexed electrical detection of cancer markers using silicon-nanowire field-effect devices in which distinct nanowires and surface receptors are incorporated into arrays. Protein markers were routinely detected at femtomolar concentrations with high selectivity, and simultaneous incorporation of control nanowires enabled discrimination against false positives. Nanowire arrays allowed highly selective and sensitive multiplexed detection of prostate specific antigen (PSA), PSA-a1-antichymotrypsin, carcinoembryonic antigen and mucin-1, including detection to at least 0.9 pg/ml in undiluted serum samples. In addition, nucleic acid receptors enabled real-time assays of the binding, activity and small-molecule inhibition of telomerase using unamplified extracts from as few as ten tumor cells. The capability for multiplexed real-time monitoring of protein markers and telomerase activity with high sensitivity and selectivity in clinically relevant samples opens up substantial possibilities for diagnosis and treatment of cancer and other complex diseases.
2,396 citations
TL;DR: Direct, real-time electrical detection of single virus particles with high selectivity by using nanowire field effect transistors is reported, suggesting potential for simultaneous detection of a large number of distinct viral threats at the single virus level.
Abstract: We report direct, real-time electrical detection of single virus particles with high selectivity by using nanowire field effect transistors. Measurements made with nanowire arrays modified with antibodies for influenza A showed discrete conductance changes characteristic of binding and unbinding in the presence of influenza A but not paramyxovirus or adenovirus. Simultaneous electrical and optical measurements using fluorescently labeled influenza A were used to demonstrate conclusively that the conductance changes correspond to binding/unbinding of single viruses at the surface of nanowire devices. pH-dependent studies further show that the detection mechanism is caused by a field effect, and that the nanowire devices can be used to determine rapidly isoelectric points and variations in receptor-virus binding kinetics for different conditions. Lastly, studies of nanowire devices modified with antibodies specific for either influenza or adenovirus show that multiple viruses can be selectively detected in parallel. The possibility of large-scale integration of these nanowire devices suggests potential for simultaneous detection of a large number of distinct viral threats at the single virus level.
1,257 citations
TL;DR: The calculations reveal that reported femtomolar detection limits for biomolecular assays are very likely an analyte transport limitation, not a signal transduction limitation.
Abstract: We examine through analytical calculations and finite element simulations how the detection efficiency of disk and wire-like biosensors in unmixed fluids varies with size from the micrometer to nanometer scales. Specifically, we determine the total flux of DNA-like analyte molecules on a sensor as a function of time and flow rate for a sensor incorporated into a microfluidic system. In all cases, sensor size and shape profoundly affect the total analyte flux. The calculations reveal that reported femtomolar detection limits for biomolecular assays are very likely an analyte transport limitation, not a signal transduction limitation. We conclude that without directed transport of biomolecules, individual nanoscale sensors will be limited to picomolar-order sensitivity for practical time scales.
603 citations
TL;DR: In this article, a micromachine-based flow chamber is designed and fabricated on plastic substrates as a micro flow cytometer, and the effect of the device geometry and relative sheath and sample flow rate on the focusing of the center flow is explored systematically.
Abstract: This paper describes hydrodynamic focusing inside a micromachined flow cytometer. Flow cytometry is a process whereby cells are analyzed and sorted based on hydrodynamic focusing phenomenon and specific cellular characteristics. In this study, the hydrodynamic focusing phenomenon is first modeled by employing potential flow theory. Then the flow field inside the flow cytometer is numerically simulated. The effect of the device geometry and relative sheath and sample flow rate on the focusing of the center flow is explored systematically. At last, a micromachine-based flow chamber is designed and fabricated on plastic substrates as a micro flow cytometer. Hydrodynamic focusing is verified with the use of microscopic visualization of water sheath flows and dyecontaining sample flow. Experimental data indicate that the size of focused sample stream can be reduced to about 3mm, which is applicable to cell sorting and counting. @DOI: 10.1115/1.1385514#
145 citations