Yong-ak Song - Academia.edu (original) (raw)

Papers by Yong-ak Song

Research paper thumbnail of Sample Preparation with Free-Flowing Biochips using Microfluidic Binary-Tree Network

2020 IEEE International Symposium on Circuits and Systems (ISCAS), 2020

Microfluidic biochips enable low-cost automation of biochemical protocols with numerous applicati... more Microfluidic biochips enable low-cost automation of biochemical protocols with numerous applications to medical diagnostics, forensics, molecular biology, and drug design. An important component of protocol design is sample preparation, which involves dilution or mixing of two or more fluids in a desired ratio of concentration factors (CF). Existing continuous-flow microfluidic biochips deploy either free-flowing networks where only a single layer of flow-channels is used devoid of any control valves, or valve-based technology where the flow-layer is augmented with a control layer of valves. While the former is easy to fabricate, reliable, and less expensive, they are typically hardwired for specific applications only. The latter class, although programmable, is expensive and prone to various manufacturing and operational defects. In this paper, we present the physical design of a microfluidic network that is free-flowing as well as programmable. The proposed valve-free network rese...

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Research paper thumbnail of A single pressure pulse-actuated 3D-printed microfluidic tip for high throughput dispensing of C. elegans worms

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Research paper thumbnail of Security Assessment of Microfluidic Fully-Programmable-Valve-Array Biochips

2019 32nd International Conference on VLSI Design and 2019 18th International Conference on Embedded Systems (VLSID), 2019

The fully-programmable-valve-array (FPVA) is a general-purpose programmable flow-based microfluid... more The fully-programmable-valve-array (FPVA) is a general-purpose programmable flow-based microfluidic platform, akin to the VLSI field-programmable gate array (FPGA). FPVAs are dynamically reconfigurable and hence are suitable in a broad spectrum of applications involving immunoassays and cell analysis. Since these applications are safety-critical, addressing security concerns is vital for the success and adoption of FPVAs. This study evaluates the security of FPVA biochips. We show that FPVAs are vulnerable to malicious operations similar to digital and flow-based microfluidic biochips. FPVAs are further prone to new classes of attacks - tunneling and deliberate aging. The study establishes security metrics and describes possible attacks on real-life bioassays.

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Research paper thumbnail of Microfluidic Trojan Design in Flow-based Biochips

2020 Design, Automation & Test in Europe Conference & Exhibition (DATE), 2020

Microfluidic technologies find application in various safety-critical fields such as medical diag... more Microfluidic technologies find application in various safety-critical fields such as medical diagnostics, drug research, and cell analysis. Recent work has focused on security threats to microfluidic-based cyberphysical systems and defenses. So far the threat analysis has been limited to the cases of tampering with control software/hardware, which is common to most cyberphysical control systems in general; in a sense, such an approach is not exclusive to microfluidics. In this paper, we present a stealthy attack paradigm that uses characteristics exclusive to the microfluidic devices - a microfluidic trojan. The proposed trojan payload is a valve whose height has been perturbed to vary its pressure response. This trojan can be triggered in multiple ways based on time or specific operations. These triggers can occur naturally in a bioassay or added into the controlling software. We showcase the trojan application in carrying out practical attacks -contamination, parameter-tampering and denial-of-service - on a real-life bioassay implementation. Further, we present guidelines to launch stealthy attacks and to counter them.

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Research paper thumbnail of Microfluidic Electrokinetic Preconcentration Chip for Enhanced Detection of Nucleic Acids and Exosomes

IEEE Nanotechnology Magazine, 2020

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Research paper thumbnail of Author Correction: A Multiwell-Based Detection Platform with Integrated PDMS Concentrators for Rapid Multiplexed Enzymatic Assays

Scientific Reports, 2018

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Research paper thumbnail of Toward Secure Microfluidic Fully Programmable Valve Array Biochips

IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 2019

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Research paper thumbnail of Rapid Detection and Trapping of Extracellular Vesicles by Electrokinetic Concentration for Liquid Biopsy on Chip

Micromachines, 2018

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Research paper thumbnail of A Multiwell-Based Detection Platform with Integrated PDMS Concentrators for Rapid Multiplexed Enzymatic Assays

Scientific reports, Jan 17, 2018

We report an integrated system for accelerating assays with concentrators in a standard 12-well p... more We report an integrated system for accelerating assays with concentrators in a standard 12-well plate (ISAAC-12) and demonstrate its versatility for rapid detection of matrix metalloproteinase (MMP)-9 expression in the cell culture supernatant of breast cancer cell line MDA-MB-231 by accelerating the enzymatic reaction and end-point signal intensity via electrokinetic preconcentration. Using direct printing of a conductive ion-permselective polymer on a polydimethylsiloxane (PDMS) channel, the new microfluidic concentrator chip can be built without modifying the underlying substrate. Through this decoupling fabrication strategy, our microfluidic concentrator chip can easily be integrated with a standard multiwell plate, the de facto laboratory standard platform for high-throughput assays, simply by reversible bonding on the bottom of each well. It increases the reaction rate of enzymatic assays by concentrating the enzyme and the reaction product inside each well simultaneously for ...

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Research paper thumbnail of High-throughput sorting of eggs for synchronization of C. elegans in a microfluidic spiral chip

Lab on a chip, Jan 13, 2018

In this study, we report the use of a high-throughput microfluidic spiral chip to screen out eggs... more In this study, we report the use of a high-throughput microfluidic spiral chip to screen out eggs from a mixed age nematode population, which can subsequently be cultured to a desired developmental stage. For the sorting of a mixture containing three different developmental stages, eggs, L1 and L4, we utilized a microfluidic spiral chip with a trapezoidal channel to obtain a sorting efficiency of above 97% and a sample purity (SP) of above 80% for eggs at different flow rates up to 10 mL min. The result demonstrated a cost-effective, simple, and highly efficient method for synchronizing C. elegans at a high throughput (∼4200 organisms per min at 6 mL min), while eliminating challenges such as clogging and non-reusability of membrane-based filtration. Due to its simplicity, our method can be easily adopted in the C. elegans research community.

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Research paper thumbnail of Detecting and Trapping of a Single C. elegans Worm in a Microfluidic Chip for Automated Microplate Dispensing

SLAS TECHNOLOGY: Translating Life Sciences Innovation, 2016

Microfluidic devices offer new technical possibilities for a precise manipulation of Caenorhabdit... more Microfluidic devices offer new technical possibilities for a precise manipulation of Caenorhabditis elegans due to the comparable length scale. C. elegans is a small, free-living nematode worm that is a popular model system for genetic, genomic, and high-throughput experimental studies of animal development and neurobiology. In this paper, we demonstrate a microfluidic system in polydimethylsiloxane (PDMS) for dispensing of a single C. elegans worm into a 96-well plate. It consists of two PDMS layers, a flow and a control layer. Using five microfluidic pneumatic valves in the control layer, a single worm is trapped upon optical detection with a pair of optical fibers integrated perpendicular to the constriction channel and then dispensed into a microplate well with a dispensing tip attached to a robotic handling system. Due to its simple design and facile fabrication, we expect that our microfluidic chip can be expanded to a multiplexed dispensation system of C. elegans worms for hi...

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Research paper thumbnail of Accelerating the Mass Transport of DNA Biomolecules Onto DNA Microarray for Enhanced Detection by Electrokinetic Concentration in a Microfluidic Chip

Volume 1: Micro/Nanofluidics and Lab-on-a-Chip; Nanofluids; Micro/Nanoscale Interfacial Transport Phenomena; Micro/Nanoscale Boiling and Condensation Heat Transfer; Micro/Nanoscale Thermal Radiation; Micro/Nanoscale Energy Devices and Systems, 2016

Morpholinos (MOs) are synthetic nucleic acids analogues with a non-charged backbone of morpholine... more Morpholinos (MOs) are synthetic nucleic acids analogues with a non-charged backbone of morpholine rings. To enhance the MO-DNA hybridization assay speed, we propose the integration of a MO microarray with an ion concentration polarization (ICP) based microfluidic concentrator. The ICP concentrator collects target biomolecules from a ∼μL fluidic DNA sample and concentrates them electrokinetically into a ∼nL plug located in the vicinity of the MO probes. ICP preconcentration not only reduces the analyte diffusion length but also increases the binding reaction rate, and as a result, ICP-enhanced MO microarrays allow much faster hybridization than standard diffusion-limited MO microarrays.

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Research paper thumbnail of Integration of Multiplexed Microfluidic Electrokinetic Concentrators with a Morpholino Microarray via Reversible Surface Bonding for Enhanced DNA Hybridization

Analytical Chemistry, 2016

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Research paper thumbnail of Enhancing the speed of morpholino-DNA biosensor by electrokinetic concentration of DNA in a microfluidic chip

Biosensors and Bioelectronics, 2015

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Research paper thumbnail of Creating sub-50 nm nanofluidic junctions in a PDMS microchip via self-assembly process of colloidal silica beads for electrokinetic concentration of biomolecules

Lab on a chip, Jan 7, 2014

In this work we describe a novel and simple self-assembly process of colloidal silica beads to cr... more In this work we describe a novel and simple self-assembly process of colloidal silica beads to create a nanofluidic junction between two microchannels. The nanoporous membrane was used to induce ion concentration polarization inside the microchannel and this electrokinetic preconcentration system allowed rapid concentration of DNA samples by ~1700 times and of protein samples by ~100 times within 5 minutes.

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Research paper thumbnail of Capillary-valve-based fabrication of ion-selective membrane junction for electrokinetic sample preconcentration in PDMS chip

Lab on a Chip, 2010

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Research paper thumbnail of Multiplexed proteomic sample preconcentration device using surface-patterned ion-selective membrane

Lab on a Chip, 2008

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Research paper thumbnail of Enhancing Protease Activity Assay in Droplet-Based Microfluidics Using a Biomolecule Concentrator

Journal of the American Chemical Society, 2011

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Research paper thumbnail of Experimental investigations into rapid prototyping of composites by novel hybrid deposition process

Journal of Materials Processing Technology, 2006

Solid Freeform Fabrication (SFF) gives engineers a new freedom to build parts that have been impo... more Solid Freeform Fabrication (SFF) gives engineers a new freedom to build parts that have been impossible to manufacture using conventional techniques. However, the surface finish and accuracy of SFF parts remain lower than those of parts that have been machined in conventional methods such as milling. A process combination of additive and subtractive techniques is currently being developed by our

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Research paper thumbnail of 3D welding and milling: Part I–a direct approach for freeform fabrication of metallic prototypes

International Journal of Machine Tools and Manufacture, 2005

Solid Freeform Fabrication (SFF) gives engineers a new freedom to build parts that have thus far ... more Solid Freeform Fabrication (SFF) gives engineers a new freedom to build parts that have thus far proved difficult to manufacture using conventional machining. However, the surface finish and accuracy of SFF parts are lower than those of conventionally machined parts. A process combination of additive and subtractive techniques is currently being developed in order to overcome this problem. A novel

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Research paper thumbnail of Sample Preparation with Free-Flowing Biochips using Microfluidic Binary-Tree Network

2020 IEEE International Symposium on Circuits and Systems (ISCAS), 2020

Microfluidic biochips enable low-cost automation of biochemical protocols with numerous applicati... more Microfluidic biochips enable low-cost automation of biochemical protocols with numerous applications to medical diagnostics, forensics, molecular biology, and drug design. An important component of protocol design is sample preparation, which involves dilution or mixing of two or more fluids in a desired ratio of concentration factors (CF). Existing continuous-flow microfluidic biochips deploy either free-flowing networks where only a single layer of flow-channels is used devoid of any control valves, or valve-based technology where the flow-layer is augmented with a control layer of valves. While the former is easy to fabricate, reliable, and less expensive, they are typically hardwired for specific applications only. The latter class, although programmable, is expensive and prone to various manufacturing and operational defects. In this paper, we present the physical design of a microfluidic network that is free-flowing as well as programmable. The proposed valve-free network rese...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A single pressure pulse-actuated 3D-printed microfluidic tip for high throughput dispensing of C. elegans worms

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Security Assessment of Microfluidic Fully-Programmable-Valve-Array Biochips

2019 32nd International Conference on VLSI Design and 2019 18th International Conference on Embedded Systems (VLSID), 2019

The fully-programmable-valve-array (FPVA) is a general-purpose programmable flow-based microfluid... more The fully-programmable-valve-array (FPVA) is a general-purpose programmable flow-based microfluidic platform, akin to the VLSI field-programmable gate array (FPGA). FPVAs are dynamically reconfigurable and hence are suitable in a broad spectrum of applications involving immunoassays and cell analysis. Since these applications are safety-critical, addressing security concerns is vital for the success and adoption of FPVAs. This study evaluates the security of FPVA biochips. We show that FPVAs are vulnerable to malicious operations similar to digital and flow-based microfluidic biochips. FPVAs are further prone to new classes of attacks - tunneling and deliberate aging. The study establishes security metrics and describes possible attacks on real-life bioassays.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Microfluidic Trojan Design in Flow-based Biochips

2020 Design, Automation & Test in Europe Conference & Exhibition (DATE), 2020

Microfluidic technologies find application in various safety-critical fields such as medical diag... more Microfluidic technologies find application in various safety-critical fields such as medical diagnostics, drug research, and cell analysis. Recent work has focused on security threats to microfluidic-based cyberphysical systems and defenses. So far the threat analysis has been limited to the cases of tampering with control software/hardware, which is common to most cyberphysical control systems in general; in a sense, such an approach is not exclusive to microfluidics. In this paper, we present a stealthy attack paradigm that uses characteristics exclusive to the microfluidic devices - a microfluidic trojan. The proposed trojan payload is a valve whose height has been perturbed to vary its pressure response. This trojan can be triggered in multiple ways based on time or specific operations. These triggers can occur naturally in a bioassay or added into the controlling software. We showcase the trojan application in carrying out practical attacks -contamination, parameter-tampering and denial-of-service - on a real-life bioassay implementation. Further, we present guidelines to launch stealthy attacks and to counter them.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Microfluidic Electrokinetic Preconcentration Chip for Enhanced Detection of Nucleic Acids and Exosomes

IEEE Nanotechnology Magazine, 2020

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Author Correction: A Multiwell-Based Detection Platform with Integrated PDMS Concentrators for Rapid Multiplexed Enzymatic Assays

Scientific Reports, 2018

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Toward Secure Microfluidic Fully Programmable Valve Array Biochips

IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 2019

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Rapid Detection and Trapping of Extracellular Vesicles by Electrokinetic Concentration for Liquid Biopsy on Chip

Micromachines, 2018

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A Multiwell-Based Detection Platform with Integrated PDMS Concentrators for Rapid Multiplexed Enzymatic Assays

Scientific reports, Jan 17, 2018

We report an integrated system for accelerating assays with concentrators in a standard 12-well p... more We report an integrated system for accelerating assays with concentrators in a standard 12-well plate (ISAAC-12) and demonstrate its versatility for rapid detection of matrix metalloproteinase (MMP)-9 expression in the cell culture supernatant of breast cancer cell line MDA-MB-231 by accelerating the enzymatic reaction and end-point signal intensity via electrokinetic preconcentration. Using direct printing of a conductive ion-permselective polymer on a polydimethylsiloxane (PDMS) channel, the new microfluidic concentrator chip can be built without modifying the underlying substrate. Through this decoupling fabrication strategy, our microfluidic concentrator chip can easily be integrated with a standard multiwell plate, the de facto laboratory standard platform for high-throughput assays, simply by reversible bonding on the bottom of each well. It increases the reaction rate of enzymatic assays by concentrating the enzyme and the reaction product inside each well simultaneously for ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of High-throughput sorting of eggs for synchronization of C. elegans in a microfluidic spiral chip

Lab on a chip, Jan 13, 2018

In this study, we report the use of a high-throughput microfluidic spiral chip to screen out eggs... more In this study, we report the use of a high-throughput microfluidic spiral chip to screen out eggs from a mixed age nematode population, which can subsequently be cultured to a desired developmental stage. For the sorting of a mixture containing three different developmental stages, eggs, L1 and L4, we utilized a microfluidic spiral chip with a trapezoidal channel to obtain a sorting efficiency of above 97% and a sample purity (SP) of above 80% for eggs at different flow rates up to 10 mL min. The result demonstrated a cost-effective, simple, and highly efficient method for synchronizing C. elegans at a high throughput (∼4200 organisms per min at 6 mL min), while eliminating challenges such as clogging and non-reusability of membrane-based filtration. Due to its simplicity, our method can be easily adopted in the C. elegans research community.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Detecting and Trapping of a Single C. elegans Worm in a Microfluidic Chip for Automated Microplate Dispensing

SLAS TECHNOLOGY: Translating Life Sciences Innovation, 2016

Microfluidic devices offer new technical possibilities for a precise manipulation of Caenorhabdit... more Microfluidic devices offer new technical possibilities for a precise manipulation of Caenorhabditis elegans due to the comparable length scale. C. elegans is a small, free-living nematode worm that is a popular model system for genetic, genomic, and high-throughput experimental studies of animal development and neurobiology. In this paper, we demonstrate a microfluidic system in polydimethylsiloxane (PDMS) for dispensing of a single C. elegans worm into a 96-well plate. It consists of two PDMS layers, a flow and a control layer. Using five microfluidic pneumatic valves in the control layer, a single worm is trapped upon optical detection with a pair of optical fibers integrated perpendicular to the constriction channel and then dispensed into a microplate well with a dispensing tip attached to a robotic handling system. Due to its simple design and facile fabrication, we expect that our microfluidic chip can be expanded to a multiplexed dispensation system of C. elegans worms for hi...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Accelerating the Mass Transport of DNA Biomolecules Onto DNA Microarray for Enhanced Detection by Electrokinetic Concentration in a Microfluidic Chip

Volume 1: Micro/Nanofluidics and Lab-on-a-Chip; Nanofluids; Micro/Nanoscale Interfacial Transport Phenomena; Micro/Nanoscale Boiling and Condensation Heat Transfer; Micro/Nanoscale Thermal Radiation; Micro/Nanoscale Energy Devices and Systems, 2016

Morpholinos (MOs) are synthetic nucleic acids analogues with a non-charged backbone of morpholine... more Morpholinos (MOs) are synthetic nucleic acids analogues with a non-charged backbone of morpholine rings. To enhance the MO-DNA hybridization assay speed, we propose the integration of a MO microarray with an ion concentration polarization (ICP) based microfluidic concentrator. The ICP concentrator collects target biomolecules from a ∼μL fluidic DNA sample and concentrates them electrokinetically into a ∼nL plug located in the vicinity of the MO probes. ICP preconcentration not only reduces the analyte diffusion length but also increases the binding reaction rate, and as a result, ICP-enhanced MO microarrays allow much faster hybridization than standard diffusion-limited MO microarrays.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Integration of Multiplexed Microfluidic Electrokinetic Concentrators with a Morpholino Microarray via Reversible Surface Bonding for Enhanced DNA Hybridization

Analytical Chemistry, 2016

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Enhancing the speed of morpholino-DNA biosensor by electrokinetic concentration of DNA in a microfluidic chip

Biosensors and Bioelectronics, 2015

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Creating sub-50 nm nanofluidic junctions in a PDMS microchip via self-assembly process of colloidal silica beads for electrokinetic concentration of biomolecules

Lab on a chip, Jan 7, 2014

In this work we describe a novel and simple self-assembly process of colloidal silica beads to cr... more In this work we describe a novel and simple self-assembly process of colloidal silica beads to create a nanofluidic junction between two microchannels. The nanoporous membrane was used to induce ion concentration polarization inside the microchannel and this electrokinetic preconcentration system allowed rapid concentration of DNA samples by ~1700 times and of protein samples by ~100 times within 5 minutes.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Capillary-valve-based fabrication of ion-selective membrane junction for electrokinetic sample preconcentration in PDMS chip

Lab on a Chip, 2010

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Multiplexed proteomic sample preconcentration device using surface-patterned ion-selective membrane

Lab on a Chip, 2008

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Enhancing Protease Activity Assay in Droplet-Based Microfluidics Using a Biomolecule Concentrator

Journal of the American Chemical Society, 2011

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Experimental investigations into rapid prototyping of composites by novel hybrid deposition process

Journal of Materials Processing Technology, 2006

Solid Freeform Fabrication (SFF) gives engineers a new freedom to build parts that have been impo... more Solid Freeform Fabrication (SFF) gives engineers a new freedom to build parts that have been impossible to manufacture using conventional techniques. However, the surface finish and accuracy of SFF parts remain lower than those of parts that have been machined in conventional methods such as milling. A process combination of additive and subtractive techniques is currently being developed by our

Bookmarks Related papers MentionsView impact

Research paper thumbnail of 3D welding and milling: Part I–a direct approach for freeform fabrication of metallic prototypes

International Journal of Machine Tools and Manufacture, 2005

Solid Freeform Fabrication (SFF) gives engineers a new freedom to build parts that have thus far ... more Solid Freeform Fabrication (SFF) gives engineers a new freedom to build parts that have thus far proved difficult to manufacture using conventional machining. However, the surface finish and accuracy of SFF parts are lower than those of conventionally machined parts. A process combination of additive and subtractive techniques is currently being developed in order to overcome this problem. A novel

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