Detection of protein kinase using an aptamer on a microchip integrated electrolyte-insulator-semiconductor sensor

Chand, Rohit,Han, Dawoon,Neethirajan, Suresh,Kim, Yong-Sang Elsevier 2017 Sensors and actuators. B Chemical Vol.248 No.-

<P><B>Abstract</B></P> <P>Herein, we developed a microchip electrolyte-insulator-semiconductor (EIS) sensor for the capacitive detection of protein kinase A (PKA). EIS sensing is customarily performed in a Teflon cell to define the sensing area. However, in this work, a rapid prototyping technique was followed to integrate polymeric microchip, a reference electrode, and the EIS sensor. The aptameric peptide was used for one-step and label-free detection of PKA enzyme. The thiolated PKA-specific aptamer was immobilized on the gold nanoparticles decorated EIS sensor surface. The detection of PKA in microchip was based on the change in surface charge of EIS sensor. We also analyzed the ability of microchip-EIS sensor to distinguish between buffers at different pH. An average sensitivity of 96mV/pH for a pH range of 5–9 was obtained. The quantitative detection of PKA was performed by analyzing the capacitance-voltage curve after the aptamer-PKA interaction. The EIS sensor showed a detection limit of 2U/mL with a relative linearity from 10U/mL to 80U/mL for the detection of PKA. This study proposes an integrated and point-of-care applicable biosensor for the rapid diagnosis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The EIS sensor integrated with microchip and reference electrode was fabricated. </LI> <LI> The microchip-EIS was used for detection of protein kinase. </LI> <LI> The change in surface charge alters the V<SUB>G</SUB> of EIS sensor. </LI> <LI> PKA was efficiently detected on-chip using aptamer. </LI> <LI> The microchip-EIS was highly specific, selective and stable. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Microchip-based cell aggregometer using stirring-disaggregation mechanism

Shin, Se-Hyun,Yang, Yi-Jie,Suh, Jang-Soo The Korean Society of Rheology 2007 Korea-Australia rheology journal Vol.19 No.3

A new microchip-based aggregometer that uses a stirring-aided disaggregation mechanism in a microchip was developed to measure red blood cell (RBC) aggregation in blood and RBC suspensions. Conventional methods of RBC disaggregation, such as the rotational Couette system, were replaced with a newly designed stirring-induced disaggregation mechanism. Using a stirrer in a microchip, the aggregated RBCs stored in a microchip can be easily disaggregated. With an abrupt halt of the stirring, the backscattered light intensity can be measured in a microchip with respect to time. The time recording of the backscattered light intensity (syllectogram) shows an exponential decreasing curve representing the RBC aggregation. By analyzing the syllectogram, aggregation indices such as AI and M were determined. The results showed excellent agreement with LORCA. The essential feature of this design is the incorporation of a disposable microchip and the stirring-induced disaggregation mechanism.

A Capillary Electrochromatographic Microchip Packed with Self-Assembly Colloidal Carboxylic Silica Beads

Jeon, In-Sun,Kim, Shin-Seon,Park, Jong-Man Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.4

An electrochromatographic microchip with carboxyl-group-derivatized mono-disperse silica packing was prepared from the corresponding colloidal silica solution by utilizing capillary action and self-assembly behavior. The silica beads in water were primed by the capillary action toward the ends of cross-patterned microchannel on a cyclic olefinic copolymer (COC) substrate. Slow evaporation of water at the front of packing promoted the self-assembled packing of the beads. After thermally binding a cover plate on the chip substrate, reservoirs for sample solutions were fabricated at the ends of the microchannel. The packing at the entrances of the microchannel was silver coated to fix utilizing an electroless silver-plating technique to prevent the erosion of the packed structure caused by the sudden switching of a high voltage DC power source. The electrochromatographic behavior of the microchip was explored and compared to that of the microchip with bare silica packing in basic borate buffer. Electrophoretic migration of Rhodamine B was dominant in the microchip with the carboxyl-derivatized silica packing that resulted in a migration approximated twice as fast, while the reversible adsorption was dominant in the bare silica-packed microchip. Not only the faster migration rates of the negatively charged FITC-derivatives of amino acids but also the different migration due to the charge interaction at the packing surface were observed. The electrochromatographic characteristics were studied in detail and compared with those of the bare silica packed microchip in terms of the packing material, the separation potential, pH of the running buffer, and also the separation channel length.

A Capillary Electrochromatographic Microchip Packed with Self-Assembly Colloidal Carboxylic Silica Beads

전인선,김신선,박종만 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.4

An electrochromatographic microchip with carboxyl-group-derivatized mono-disperse silica packing was prepared from the corresponding colloidal silica solution by utilizing capillary action and self-assembly behavior. The silica beads in water were primed by the capillary action toward the ends of cross-patterned microchannel on a cyclic olefinic copolymer (COC) substrate. Slow evaporation of water at the front of packing promoted the self-assembled packing of the beads. After thermally binding a cover plate on the chip substrate, reservoirs for sample solutions were fabricated at the ends of the microchannel. The packing at the entrances of the microchannel was silver coated to fix utilizing an electroless silver-plating technique to prevent the erosion of the packed structure caused by the sudden switching of a high voltage DC power source. The electrochromatographic behavior of the microchip was explored and compared to that of the microchip with bare silica packing in basic borate buffer. Electrophoretic migration of Rhodamine B was dominant in the microchip with the carboxyl-derivatized silica packing that resulted in a migration approximated twice as fast, while the reversible adsorption was dominant in the bare silica-packed microchip. Not only the faster migration rates of the negatively charged FITC-derivatives of amino acids but also the different migration due to the charge interaction at the packing surface were observed. The electrochromatographic characteristics were studied in detail and compared with those of the bare silica packed microchip in terms of the packing material, the separation potential, pH of the running buffer, and also the separation channel length.

Microchip-based cell aggregometer using strring disaggregation mechnism

신세현,양이지에,서장수 한국유변학회 2007 Korea-Australia rheology journal Vol.19 No.3

A new microchip-based aggregometer that uses a stirring-aided disaggregation mechanism in a microchip was developed to measure red blood cell (RBC) aggregation in blood and RBC suspensions. Conventional methods of RBC disaggregation, such as the rotational Couette system, were replaced with a newly designed stirring-induced disaggregation mechanism. Using a stirrer in a microchip, the aggregated RBCs stored in a microchip can be easily disaggregated. With an abrupt halt of the stirring, the backscattered light intensity can be measured in a microchip with respect to time. The time recording of the backscattered light intensity (syllectogram) shows an exponential decreasing curve representing the RBC aggregation. By analyzing the syllectogram, aggregation indices such as AI and M were determined. The results showed excellent agreement with LORCA. The essential feature of this design is the incorporation of a disposable microchip and the stirring-induced disaggregation mechanism.

Microchip-based multiplex electro-immunosensing system for the detection of cancer biomarkers

Ko, Yong-Jun,Maeng, Joon-Ho,Ahn, Yoomin,Hwang, Seung Yong,Cho, Nahm-Gyoo,Lee, Seoung-Hwan WILEY-VCH Verlag 2008 Electrophoresis Vol.29 No.16

<P>Microfluidic-based microchips have become the focus of research interest for immunoassays and biomarker diagnostics. This is due to their aptitude for high-throughput processing, small sample volume, and short analysis times. In this paper, we describe the development of a microchip-based multiplex electro-immunosensing system for simultaneous detection of cancer biomarkers using gold nanoparticles and silver enhancer. Our microchip is composed of biocompatible poly(PDMS) and glass substrates. To fix the antibody-immobilized microbeads, we used pillar-type microfilters within a reaction chamber. An immunogold silver staining (IGSS) method was used to amplify the electrical signal that corresponded to the immunecomplex. To demonstrate this approach, we simultaneously assayed three cancer biomarkers, alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), and prostate-specific antigen (PSA) on the microchip. The electrical signal generated from the result of the immunoreaction was measured and monitored by a PC-based system. The overall assay time was reduced from 3–8 h to about 55 min when compared to conventional immunoassays. The working range of the proposed microchip was from 10<SUP>−</SUP><SUP>3</SUP> to 10<SUP>−1</SUP> μg/mL of the target antigen.</P>

2P-353 Development of Microchip-Based Electrophoresis for Single-Strand Conformation Polymorphism Analysis

신기영,정규열 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

Microchip electrophoresis are useful methods for genetic analysis by the benefit of rapid analysis, small amount of sample/reagent consumption, and portability. Capillary electrophoresis-single strand conformation polymorphism (CE-SSCP) analysis is one of promising DNA detection method due to its simplicity and versatility. In non-denaturing conditions, single-strand DNA forms a folded conformation that is determined by its sequence. In SSCP analysis, electrophoretic mobility of DNA fragment is influenced by its folded shape and size. Theoretically, any DNA sequence variation can be detected with SSCP electrophoretic mobility pattern. However, low separation resolution is a critical limitation of SSCP analysis on microchip. In this study, we improved separation resolution via microchannel width control. As a result, this microchip-SSCP analysis system was successfully applied to the pathogen detection and SNP marker detection.

주화성에 의한 활동성 정자 분리용 마이크로 바이오칩에 관한 연구

고용준(Yongjun Ko),맹준호(Joon-Ho Maeng),안유민(Yoomin Ahn),황승용(Seung Yong Hwang) 대한기계학회 2008 大韓機械學會論文集A Vol.32 No.12

This paper presents a new microchip which can separate motile sperm by chemotaxis. The microchip was developed to create longitudinal concentration gradient in the microchannel due to diffusion. Linearly good concentration gradient of chemoattractant was generated without any fluid control devices. In sperm separation experiment with the developed microchip, mouse sperm was used as sample and acetylcholine was selected as chemoattractant. Human tubal fluid (HTF), buffer solution, was introduced into the microchannel of the microchip and attractants diluted in ratio of 1, 1/2, 1/4, 1/8, 1/16, 1/32 and 1/64 including control (DI water) were dropped in each outlet by 2 ㎕ volume with micropippet. After 5min, 1 ㎕ sperm solution was dropped into inlet of the chip. After 10 min, when sperms reached to the outlet by chemotaxis, we counted sperms in each outlet by using microscopy. Consequently, we could separate progressive motile sperm with the new microchip. In the experiment, the most sperms were isolated at the outlet dropped with 1/16 diluted solution. The optimal concentration gradient to induce chemotaxis was about 0.625 ㎎/㎖/㎜.

He-Polymer Microchip Plasma (PMP) System Incorporating a Gas Liquid Separator for the Determination of Chlorine Levels in a Sanitizer Liquid

Oh, Joo-Suck,Kim, Y.H.,Lim, H.B. Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.3

The authors describe an analytical method to determine total chlorine in a sanitizer liquid, incorporating a lab-made He-rf-plasma within a PDMS polymer microchip. Helium was used instead of Ar to produce a plasma to achieve efficient Cl excitation. A quartz tube 1 mm i.d. was embedded in the central channel of the polymer microchip to protect it from damage. Rotational temperature of the He-microchip plasma was in the range 1350-3600 K, as estimated from the spectrum of the OH radical. Chlorine was generated in a volatilization reaction vessel containing potassium permanganate in combination of sulfuric acid and then introduced into the polymer microchip plasma (PMP). Atomic emission lines of Cl at 438.2 nm and 837.7 nm were used for analysis; no emission was observed for Ar plasma. The achieved limit of detection was 0.81 ${\mu}g\;mL^{-1}$ (rf powers of 30-70 W), which was sensitive enough to analyze sanitizers that typically contained 100-200 ${\mu}g\;mL^{-1}$ of free chlorine in chlorinated water. This study demonstrates the usefulness of the devised PMP system in the food sciences and related industries.

He-Polymer Microchip Plasma (PMP) System Incorporating a Gas-Liquid Separator for the Determination of Chlorine Levels in a Sanitizer Liquid

Joosuck Oh,Y. H. Kim,H. B. Lim 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.3

The authors describe an analytical method to determine total chlorine in a sanitizer liquid, incorporating a lab-made He-rf-plasma within a PDMS polymer microchip. Helium was used instead of Ar to produce a plasma to achieve efficient Cl excitation. A quartz tube 1 mm i.d. was embedded in the central channel of the polymer microchip to protect it from damage. Rotational temperature of the He-microchip plasma was in the range 1350-3600 K, as estimated from the spectrum of the OH radical. Chlorine was generated in a volatilization reaction vessel containing potassium permanganate in combination of sulfuric acid and then introduced into the polymer microchip plasma (PMP). Atomic emission lines of Cl at 438.2 nm and 837.7 nm were used for analysis; no emission was observed for Ar plasma. The achieved limit of detection was 0.81 μg mL-1 (rf powers of 30-70 W), which was sensitive enough to analyze sanitizers that typically contained 100-200 μg mL-1 of free chlorine in chlorinated water. This study demonstrates the usefulness of the devised PMP system in the food sciences and related industries.