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Ahmad S, Hossain MN, Ahmadi S, Kerman K, Kraatz HB. Electrochemical distinction of neuronal and neuroblastoma cells via the phosphorylation of the cellular extracellular membrane. Anal Biochem 2021; 645:114434. [PMID: 34785194 DOI: 10.1016/j.ab.2021.114434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/10/2021] [Accepted: 10/21/2021] [Indexed: 11/20/2022]
Abstract
In this contribution we establish a proof of concept method for monitoring, quantifying and differentiating the extracellular phosphorylation of Human SHSY5Y undifferentiated neuronal cells and neuroblastoma cells by three prominent ectokinases PKA, PKC and Src. Herein it is demonstrated that a combination of different experimental techniques, including fluroesence microscopy, quartz crystal microscopy (QCM) and electrochemistry, can be used to detect extracellular phosphorylation levels of neuronal and neuroblastoma cells. Phosphorylation profiles of the three ectokinases, PKA, PKC and Src, were investigated using fluorescence microscopy and the number of phosphorylation sites per kinase was estimated using QCM. Finally, the phosphorylation of the extracellular membrane was determined using electrochemistry. Our results clearly demonstrate that the extracellular phosphorylation of neuronal cells differs significantly in terms of its phosphorylation profile from diseased neuroblastoma cells and the strength of surface electrochemical techniques in the differentiation process. We reveal that using electrochemistry, the percent compositions of neuronal and neuroblastoma cells can also be identified.
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Affiliation(s)
- S Ahmad
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, M1C 1A4, Canada; Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, M5S 3H6, Canada
| | - M N Hossain
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, M1C 1A4, Canada; Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, M5S 3H6, Canada
| | - S Ahmadi
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, M1C 1A4, Canada; Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, M5S 3H6, Canada
| | - K Kerman
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, M1C 1A4, Canada; Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, M5S 3H6, Canada
| | - H-B Kraatz
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, M1C 1A4, Canada; Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, M5S 3H6, Canada.
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2
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Fu Y, Liu L, Li X, Chen H, Wang Z, Yang W, Zhang H, Zhang H. Peptide modified manganese-doped iron oxide nanoparticles as a sensitive fluorescence nanosensor for non-invasive detection of trypsin activity in vitro and in vivo. RSC Adv 2021; 11:2213-2220. [PMID: 35424166 PMCID: PMC8693661 DOI: 10.1039/d0ra08171j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 12/08/2020] [Indexed: 01/22/2023] Open
Abstract
Herein, a fluorescence turn-on nanosensor (MnIO@pep-FITC) has been proposed for detecting trypsin activity in vitro and in vivo through covalently immobilizing an FITC modified peptide substrate of trypsin (pep-FITC) on manganese-doped iron oxide nanoparticle (MnIO NP) surfaces via a polyethylene glycol (PEG) crosslinker. The conjugation of pep-FITC with MnIO NPs results in the quenching of FITC fluorescence. After trypsin cleavage, the FITC moiety is released from the MnIO NP surface, leading to a remarkable recovery of FITC fluorescence signal. Under the optimum experimental conditions, the recovery ratio of FITC fluorescence intensity is linearly dependent on the trypsin concentration in the range of 2 to 100 ng mL-1 in buffer and intracellular trypsin in the lysate of 5 × 102 to 1 × 104 HCT116 cells per mL, respectively. The detection limit of trypsin is 0.6 ng mL-1 in buffer or 359 cells per mL HCT116 cell lysate. The MnIO@pep-FITC is successfully employed to noninvasively monitor trypsin activity in the ultrasmall (ca. 4.9 mm3 in volume) BALB/c nude mouse-bearing HCT116 tumor by in vivo fluorescence imaging with external magnetic field assistance, demonstrating that it has excellent practicability.
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Affiliation(s)
- Yu Fu
- College of Chemistry, Jilin University Changchun 130021 P. R. China
- Department of Radiology, The First Hospital of Jilin University Changchun 130021 P. R. China
| | - Lin Liu
- College of Chemistry, Jilin University Changchun 130021 P. R. China
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun 130022 P. R. China +86-431-85262243 +86-431-85262757
| | - Xiaodong Li
- Department of Radiology, The First Hospital of Jilin University Changchun 130021 P. R. China
| | - Hongda Chen
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun 130022 P. R. China +86-431-85262243 +86-431-85262757
| | - Zhenxin Wang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun 130022 P. R. China +86-431-85262243 +86-431-85262757
| | - Wensheng Yang
- College of Chemistry, Jilin University Changchun 130021 P. R. China
| | - Hua Zhang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences Changchun 130022 P. R. China +86-431-85262243 +86-431-85262757
| | - Huimao Zhang
- Department of Radiology, The First Hospital of Jilin University Changchun 130021 P. R. China
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Ahmad S, Hossain MN, Ahmadi S, Kerman K, Kraatz HB. Electrochemical detection of neuronal extracellular phosphorylation by PKA, PKC and Src. Anal Biochem 2020; 608:113892. [PMID: 32810472 DOI: 10.1016/j.ab.2020.113892] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/21/2020] [Accepted: 07/24/2020] [Indexed: 11/30/2022]
Abstract
The focus of this work described here is to establish a method for monitoring and quantifying the extracellular phosphorylation of Human SHSY5Y undifferentiated neuronal cells by three ectokinases PKA, PKC and Src; these are kinases that are known to be present in the extracellular matrix. Here is demonstrated that a combination of different experimental techniques, including microscopy and electrochemistry, can be used to detect extracellular phosphorylations. Phosphorylation profiles of the three ectokinases, PKA, PKC and Src, were investigated using fluorescence microscopy and the number of phosphorylation sites per kinase was estimated using QCM. Finally, the phosphorylation of the extracellular membrane was determined using electrochemistry. Our results clearly demonstrate the extracellular phosphorylation of neuronal cells and the strength of surface electrochemical techniques in the investigation of cellular phosphorylation.
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Affiliation(s)
- S Ahmad
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, M1C 1A4, Canada; Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, M5S 3H6, Canada
| | - M N Hossain
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, M1C 1A4, Canada; Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, M5S 3H6, Canada
| | - S Ahmadi
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, M1C 1A4, Canada; Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, M5S 3H6, Canada
| | - K Kerman
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, M1C 1A4, Canada; Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, M5S 3H6, Canada
| | - H-B Kraatz
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, M1C 1A4, Canada; Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, M5S 3H6, Canada.
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4
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Remote biosensor for the determination of trypsin by using nanoporous anodic alumina as a three-dimensional nanostructured material. Sci Rep 2020; 10:2356. [PMID: 32047212 PMCID: PMC7012875 DOI: 10.1038/s41598-020-59287-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 01/21/2020] [Indexed: 12/19/2022] Open
Abstract
The determination of trypsin in the human real sample is a routine medical investigation to assess the pancreatic disease. Herein, we fabricated an interferometric reflectance spectroscopy based biosensor for the determination trypsin. For this purpose, urease and fluorescein 5(6)-isothiocyanate (FLITC) were immobilized on the nanoporous anodic alumina (NAA). The operation principle of the proposed biosensor is based on the change in the pH of the solution during the reaction of urease and urea and therefore change in the light-absorbing ability of FLITC in the presence of trypsin. The reaction of the urease enzyme with urea increased the pH of the solution because of producing ammonia. This increase in the pH of solution increased the light-absorbing ability of the immobilized FLITC on NAA and therefore the intensity of the reflected light from the NAA to the charge-coupled device detector decreased. In the presence of trypsin, the catalytic activity of immobilized urease on NAA decreased. This decrease in the activity of urease enzyme consequent on the decrease in the amount of the generated ammonia. Therefore, the immobilized FLITC on the NAA did not absorb more light and consciously, the intensity of the light reflected light into the detector increased. The proposed biosensor exhibited a good response to the concentration of trypsin in the range of 0.25–20 μg.mL−1 with the limit of detection of 0.06 μg.mL−1.
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5
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Electrochemical studies of human nAChR a7 subunit phosphorylation by kinases PKA, PKC and Src. Anal Biochem 2019; 574:46-56. [DOI: 10.1016/j.ab.2019.03.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/19/2019] [Accepted: 03/19/2019] [Indexed: 12/19/2022]
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Gelatin-Enabled Microsensor for Pancreatic Trypsin Sensing. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8020208] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Duan C, Alibakhshi MA, Kim DK, Brown CM, Craik CS, Majumdar A. Label-Free Electrical Detection of Enzymatic Reactions in Nanochannels. ACS NANO 2016; 10:7476-84. [PMID: 27472431 DOI: 10.1021/acsnano.6b02062] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We report label-free electrical detection of enzymatic reactions using 2-D nanofluidic channels and investigate reaction kinetics of enzymatic reactions on immobilized substrates in nanoscale-confined spaces. Trypsin proteolysis is chosen for demonstration of the detection scheme. When trypsin cleaves poly-l-lysine coated on the surface of silica nanochannels, the resulting change of surface charge density can be detected by monitoring the ionic conductance of the nanochannels. Our results show that detection of such surface enzymatic reactions is faster than detection of surface binding reactions in nanochannels for low-concentration analytes. Furthermore, the nanochannel sensor has a sensitivity down to 5 ng/mL, which statistically corresponds to a single enzyme per nanochannel. Our results also suggest that enzyme kinetics in nanochannels is fundamentally different from that in bulk solutions or plain surfaces. Such enzymatic reactions form two clear self-propagating reaction fronts inside the nanochannels, and the reaction fronts follow square-root time dependences at high enzyme concentrations due to significant nonspecific adsorption. However, at low enzyme concentrations when nonspecific adsorption is negligible, the reaction fronts propagate linearly with time, and the corresponding propagation speed is related to the channel geometry, enzyme concentration, catalytic reaction constant, diffusion coefficient, and substrate surface density. Optimization of this nanochannel sensor could lead to a quick-response, highly sensitive, and label-free sensor for enzyme assay and kinetic studies.
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Affiliation(s)
- Chuanhua Duan
- Department of Mechanical Engineering, Boston University , Boston, Massachusetts 02215, United States
| | - Mohammad Amin Alibakhshi
- Department of Mechanical Engineering, Boston University , Boston, Massachusetts 02215, United States
| | - Dong-Kwon Kim
- Department of Mechanical Engineering, Ajou University , Suwon 443-749, South Korea
| | - Christopher M Brown
- Department of Pharmaceutical Chemistry, University of California , San Francisco, California 94158, United States
| | - Charles S Craik
- Department of Pharmaceutical Chemistry, University of California , San Francisco, California 94158, United States
| | - Arun Majumdar
- Department of Mechanical Engineering, Stanford University , Stanford, California 94305, United States
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Shotgun Proteomics Analysis of Estrogen Effects in the Uterus Using Two-Dimensional Liquid Chromatography and Tandem Mass Spectrometry. Methods Mol Biol 2016; 1366:131-148. [PMID: 26585132 DOI: 10.1007/978-1-4939-3127-9_11] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
Shotgun (gel-free) proteomics is a useful approach to perform identification and relative quantification of protein in complex mixtures such as tissue homogenates, biological fluids, cell lysates, and extracellular proteins. Incorporation of separative and analytical techniques such as two-dimensional liquid chromatography at nanoscale (2D-nanoLC) coupled to tandem mass spectrometry (MS/MS analysis) into the shotgun protocol provides an excellent strategy. This chapter describes the application of the shotgun proteomics protocol to evaluate the identity and expression analysis of proteins from rat uterus after estrogen (ethinylestradiol) treatment. The steps of the protocol involve sample preparation (digestion), 2D-nanoLC-MS/MS analysis, and shotgun proteomics analysis including bioinformatics tools for data conversion, organization, and interpretation.
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9
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Petryayeva E, Algar WR. Proteolytic Assays on Quantum-Dot-Modified Paper Substrates Using Simple Optical Readout Platforms. Anal Chem 2013; 85:8817-25. [DOI: 10.1021/ac4020066] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Eleonora Petryayeva
- Department
of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British
Columbia V6T 1Z1, Canada
| | - W. Russ Algar
- Department
of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British
Columbia V6T 1Z1, Canada
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10
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High sensitive trypsin activity evaluation applying a nanostructured QCM-sensor. Biosens Bioelectron 2013; 41:862-6. [DOI: 10.1016/j.bios.2012.08.039] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 08/06/2012] [Accepted: 08/16/2012] [Indexed: 11/18/2022]
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Martić S, Gabriel M, Turowec JP, Litchfield DW, Kraatz HB. Versatile Strategy for Biochemical, Electrochemical and Immunoarray Detection of Protein Phosphorylations. J Am Chem Soc 2012; 134:17036-45. [DOI: 10.1021/ja302586q] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Sanela Martić
- Department of Physical and Environmental
Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada, and Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Michelle Gabriel
- Department of Biochemistry,
Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
| | - Jacob P. Turowec
- Department of Biochemistry,
Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
| | - David W. Litchfield
- Department of Biochemistry,
Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
| | - Heinz-Bernhard Kraatz
- Department of Physical and Environmental
Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada, and Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
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12
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Hu QZ, Jang CH. Imaging trypsin activity through changes in the orientation of liquid crystals coupled to the interactions between a polyelectrolyte and a phospholipid layer. ACS APPLIED MATERIALS & INTERFACES 2012; 4:1791-1795. [PMID: 22394113 DOI: 10.1021/am300043d] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this study, we developed a new type of liquid crystal (LC)-based sensor for the real-time and label-free monitoring of enzymatic activity through changes in the orientation of LCs coupled to the interactions between polyelectrolyte and phospholipid. The LCs changed from dark to bright after an aqueous solution of poly-l-lysine (PLL) was transferred onto a self-assembled monolayer of the phospholipid, dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DOPG), at the aqueous/LC interface. Interactions between the positively charged PLL and the negatively charged DOPG drove the reorganization of the phospholipid membrane, which induced an orientational transition in the LCs from a homeotropic to planar state. Since the serine endopeptidase trypsin can enzymatically catalyze the hydrolysis of PLL, the dark-to-bright shift in the optical response was not observed after transferring a mixed solution of PLL and trypsin onto the DOPG-decorated LC interface, indicating that no orientational transitions in the LCs occurred. However, the optical response from dark to bright was observed when the mixture in the optical cell was replaced by an aqueous solution of PLL. Control experiments with trypsin or an aqueous mixture of PLL and deactivated trypsin further confirmed the feasibility of this approach. The detection limit of trypsin was determined to be ~1 μg/mL. This approach holds great promise for use in the development of LC-based sensors for the detection of enzymatic reactions in cases where the biological polyelectrolyte substrates of enzymes could disrupt the organization of the membrane and induce orientational transitions of LCs at the aqueous/LC interface.
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Affiliation(s)
- Qiong-Zheng Hu
- Department of BioNano Technology, Gachon University, San 65, Bokjeong-Dong, Sujeong-Gu, Seongnam-City, Gyeonggi-Do, 461-701, Korea
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13
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Martić S, Labib M, Kraatz HB. Electrochemical investigations of sarcoma-related protein kinase inhibition. Electrochim Acta 2011. [DOI: 10.1016/j.electacta.2011.05.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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14
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An array of field-effect nanoplate SOI capacitors for (bio-)chemical sensing. Biosens Bioelectron 2011; 26:3023-8. [DOI: 10.1016/j.bios.2010.12.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 11/29/2010] [Accepted: 12/01/2010] [Indexed: 11/19/2022]
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15
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Dubey G, Rosei F, Lopinski GP. Highly sensitive electrical detection of TCNE on chemically passivated silicon-on-insulator. Chem Commun (Camb) 2011; 47:10593-5. [DOI: 10.1039/c1cc12504d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Dubey G, Rosei F, Lopinski GP. Molecular modulation of conductivity on H-terminated silicon-on-insulator substrates. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2010; 6:2892-2899. [PMID: 21080387 DOI: 10.1002/smll.201001285] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The adsorption of a range of molecular species (water, pyridine, and ammonia) is found to reversibly modulate the conductivity of hydrogen-terminated silicon-on-insulator (H-SOI) substrates. Simultaneous sheet-resistance and Hall-effect measurements on moderately doped (10(15) cm(-3)) n- and p-type H-SOI samples mounted in a vacuum system are used to monitor the effect of gas exposure in the Torr range on the electrical-transport properties of these substrates. Reversible physisorption of "hole-trapping" species, such as pyridine (C(5)H(5)N) and ammonia (NH(3)) produces highly conductive minority-carrier channels (inversion) on p-type substrates, mimicking the action of a metallic gate in a field-effect transistor. The adsorption of these same molecules on n-type SOI induces strong electron-accumulation layers. Minority/majority channels are also formed upon controlled exposure to water vapor. These observations can be explained by a classical band-bending model, which considers the adsorbates as the source of a uniform surface charge ranging from +10(11) to +10(12)q cm(-2). These results demonstrate the utility of DC transport measurements of SOI platforms for studies of molecular adsorption and charge-transfer effects at semiconductor surfaces.
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Affiliation(s)
- Girjesh Dubey
- Steacie Institute for Molecular Sciences, National Research Council, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada
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Adjémian J, Anne A, Cauet G, Demaille C. Cleavage-sensing redox peptide monolayers for the rapid measurement of the proteolytic activity of trypsin and alpha-thrombin enzymes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:10347-10356. [PMID: 20329721 DOI: 10.1021/la100397g] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Ferrocene (Fc)-labeled peptides are end-grafted onto gold electrodes via a flexible polyethylene glycol (PEG) linker, and their ability to act as substrates for proteolytic enzymes trypsin and alpha-thrombin is investigated by cyclic voltammetry. It is shown that whereas a short Fc-tetrapeptide substrate is rapidly cleaved by trypsin, a longer Fc-heptapeptide substrate is required for alpha-thrombin detection. However, in both cases it is observed that not all of the Fc-peptide chains present on the electrode surface are cleavable by the proteases and that the cleavage yield is actually controlled by the surface coverage in the Fc-peptide. Surface dilution of the Fc-peptide using a backfilling molecule such as MCH (6-mercapto-1-hexanol) was required to obtain a cleavage yield larger than 80%. The kinetics of Fc-peptide cleavage by trypsin or alpha-thrombin is then shown to be adequately described by Michaelis Menten kinetics, allowing enzymatic constants k(cat) and K(M) to be determined. The obtained rate constant values showed that the affinity of the enzymes for their respective Fc-peptide substrates is very high (i.e., low K(M) values) whereas that for the cleavage step itself is relatively low (low k(cat) values). Partial compensation of these parameters yields a fast response of the Fc-peptide electrodes to the proteases in solution in the 1-1000 nM range. The type of molecule used to backfill the Fc-peptide layers, either MCH or PEG(6) chains, is shown to modulate the activity of the proteases versus the Fc-peptide layers: in particular, the PEG(6) diluent is specifically shown to decrease the ability of alpha-thrombin to cleave its Fc-peptide substrate whereas trypsin activity is unaffected by the presence of PEG chains.
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Affiliation(s)
- Jocelyne Adjémian
- HORIBA Medical Parc Euromédecine, rue du Caducée, BP7290 34184 Montpellier Cedex 4, France
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18
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Abouzar M, Ingebrandt S, Poghossian A, Zhang Y, Vu X, Moritz W, Schöning M. Nanoplate field-effect capacitive (bio-)chemical sensor array based on SOI structure. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.proche.2009.07.167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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19
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Bi X, Lai SL, Yang KL. Liquid Crystal Multiplexed Protease Assays Reporting Enzymatic Activities as Optical Bar Charts. Anal Chem 2009; 81:5503-9. [DOI: 10.1021/ac900793w] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xinyan Bi
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117576
| | - Siok Lian Lai
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117576
| | - Kun-Lin Yang
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117576
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