151
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Ciampi S, Guan B, Darwish NA, Zhu Y, Reece PJ, Justin Gooding J. A multimodal optical and electrochemical device for monitoring surface reactions: redox active surfaces in porous silicon Rugate filters. Phys Chem Chem Phys 2012; 14:16433-9. [DOI: 10.1039/c2cp43461j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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152
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Wang MCP, Gates BD. Synthesis of selenium nano-composite (t-Se@PS) by surface initiated atom transfer radical polymerization. Chem Commun (Camb) 2012; 48:8589-91. [DOI: 10.1039/c2cc33754a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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153
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Cheng X, Gondosiswanto R, Ciampi S, Reece PJ, Gooding JJ. One-pot synthesis of colloidal silicon quantum dots and surface functionalization via thiol–ene click chemistry. Chem Commun (Camb) 2012; 48:11874-6. [DOI: 10.1039/c2cc35954e] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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154
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Ciampi S, James M, Le Saux G, Gaus K, Justin Gooding J. Electrochemical “Switching” of Si(100) Modular Assemblies. J Am Chem Soc 2011; 134:844-7. [DOI: 10.1021/ja210048x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Simone Ciampi
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052,
Australia
| | - Michael James
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052,
Australia
- Bragg Institute, Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Guillaume Le Saux
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052,
Australia
| | - Katharina Gaus
- Centre for Vascular Research, The University of New South Wales, Sydney, NSW 2052,
Australia
| | - J. Justin Gooding
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052,
Australia
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155
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Huck LA, Buriak JM. Toward a Mechanistic Understanding of Exciton-Mediated Hydrosilylation on Nanocrystalline Silicon. J Am Chem Soc 2011; 134:489-97. [DOI: 10.1021/ja208604r] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lawrence A. Huck
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, and National Research Council Canada, National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, Alberta T6G 2M9, Canada
| | - Jillian M. Buriak
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, and National Research Council Canada, National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, Alberta T6G 2M9, Canada
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156
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Gooding JJ, Darwish N. The rise of self-assembled monolayers for fabricating electrochemical biosensors-an interfacial perspective. CHEM REC 2011; 12:92-105. [DOI: 10.1002/tcr.201100013] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Indexed: 11/08/2022]
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157
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Marshall N, Locklin J. Reductive electrografting of benzene (p-bisdiazonium hexafluorophosphate): a simple and effective protocol for creating diazonium-functionalized thin films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:13367-13373. [PMID: 21932775 DOI: 10.1021/la2024617] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this Article, we describe a protocol for surface functionalization of benzenediazonium hexafluorophosphate monolayers by in situ electrochemical reduction of bis(benzenediazonium) hexafluorophosphate. Due to the considerable difference in potential between the first and second reduction of this species, it is possible to form a high density of surface-bound diazonium groups by use of a mild potential which selectively reduces only one diazonium group per ring. The resulting diazonium-containing monolayer reacts readily with solutions of electron-rich aromatic compounds. The reaction with ferrocene produces a dense (2.7 × 10(-10) mol/cm(2)) ferrocene-containing monolayer through a Gomberg-Bachmann type arylation. The resulting ferrocene group exhibits relatively rapid electron transfer to the electrode due to the conjugated linker layer as measured by alternating current voltammetry (ACV) and cyclic voltammetry. Aromatic systems with π-donor substitutents (N,N-dimethylaniline, N,N,N',N'-tetramethyldiaminobenzophenone, and hydroquinone) react through an azo-coupling to form monolayers linked to the surface through an azobenzene moiety. The redox properties of these electron-rich species tethered to the surface were observed and quantified using cyclic voltammetry. This simple and versatile functionalization procedure has a wide variety of potential applications in surface science and materials research.
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Affiliation(s)
- Nicholas Marshall
- Department of Chemistry, Faculty of Engineering, and Center for Nanoscale Science and Engineering, University of Georgia, Athens, Georgia 30602, United States
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158
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Kelly TL, Garcia Sega A, Sailor MJ. Identification and quantification of organic vapors by time-resolved diffusion in stacked mesoporous photonic crystals. NANO LETTERS 2011; 11:3169-3173. [PMID: 21749119 DOI: 10.1021/nl201385p] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Microsensors for gas-phase analytes are fundamentally limited by their inability to discriminate between analytes. While cross-reactive arrays consisting of multiple different sensor elements provide one means to identify individual analytes, these "artificial nose" devices rely on complicated data processing algorithms and they generally suffer from significant zero-point drift. Herein, we present a single component optical sensor that is capable of identifying chemical compounds at parts-per-million concentrations. The device consists of a stack of three mesoporous silicon-based photonic crystals; a porous "drift tube" is sandwiched between two optically responsive layers. The drift layer temporally separates the optical responses of the other layers, and this difference is shown to be characteristic of the analyte.
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Affiliation(s)
- Timothy L Kelly
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, United States
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159
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Li Y, Cai C. Click chemistry-based functionalization on non-oxidized silicon substrates. Chem Asian J 2011; 6:2592-605. [PMID: 21751406 DOI: 10.1002/asia.201100294] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Indexed: 11/07/2022]
Abstract
Copper-catalyzed azide-alkyne cycloaddition (CuAAC), combined with the chemical stability of the Si-C-bound organic layer, serves as an efficient tool for the modification of silicon substrates, particularly for the immobilization of complex biomolecules. This review covers recent advances in the preparation of alkynyl- or azido-terminated "clickable" platforms on non-oxidized silicon and their further derivatization by means of the CuAAC reaction. The exploitation of these "click"-functionalized organic thin films as model surfaces to study many biological events was also addressed, as they are directly relevant to the on-going effort of creating silicon-based molecular electronics and chemical/biomolecular sensors.
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Affiliation(s)
- Yan Li
- Department of Chemistry & Center for Materials Chemistry, University of Houston, Houston, Texas 77204, USA
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160
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Ciampi S, James M, Michaels P, Gooding JJ. Tandem "click" reactions at acetylene-terminated Si(100) monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:6940-6949. [PMID: 21557551 DOI: 10.1021/la2013733] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We demonstrate a simple method for coupling alkynes to alkynes. The method involves tandem azide-alkyne cycloaddition reactions ("click" chemistry) for the immobilization of 1-alkyne species onto an alkyne modified surface in a one-pot procedure. In the case presented, these reactions take place on a nonoxidized Si(100) surface although the approach is general for linking alkynes to alkynes. The applicability of the method in the preparation of electrically well-behaved functionalized surfaces is demonstrated by coupling an alkyne-tagged ferrocene species onto alkyne-terminated Si(100) surfaces. The utility of the approach in biotechnology is shown by constructing a DNA sensing interface by derivatization of the acetylenyl surface with commercially available alkyne-tagged oligonucleotides. Cyclic voltametry, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and X-ray reflectometry are used to characterize the coupling reactions and performance of the final modified surfaces. These data show that this synthetic protocol gives chemically well-defined, electronically well-behaved, and robust (bio)functionalized monolayers on silicon semiconducting surfaces.
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Affiliation(s)
- Simone Ciampi
- School of Chemistry, The University of New South Wales, Sydney NSW 2052, Australia
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161
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Uchida K, Yamanoi Y, Yonezawa T, Nishihara H. Reversible On/Off Conductance Switching of Single Diarylethene Immobilized on a Silicon Surface. J Am Chem Soc 2011; 133:9239-41. [DOI: 10.1021/ja203269t] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kazuki Uchida
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yoshinori Yamanoi
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tetsu Yonezawa
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hiroshi Nishihara
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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162
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Kelly JA, Shukaliak AM, Fleischauer MD, Veinot JGC. Size-Dependent Reactivity in Hydrosilylation of Silicon Nanocrystals. J Am Chem Soc 2011; 133:9564-71. [DOI: 10.1021/ja2025189] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Joel A. Kelly
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Amber M. Shukaliak
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
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163
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Rijksen B, van Lagen B, Zuilhof H. Mimicking the Silicon Surface: Reactivity of Silyl Radical Cations toward Nucleophiles. J Am Chem Soc 2011; 133:4998-5008. [DOI: 10.1021/ja110844e] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bart Rijksen
- Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands
| | - Barend van Lagen
- Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands
| | - Han Zuilhof
- Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands
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164
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Soria FA, Patrito EM, Paredes-Olivera P. On the mechanism of silicon activation by halogen atoms. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:2613-2624. [PMID: 21338085 DOI: 10.1021/la104701g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Despite the widespread use of chlorinated silicon as the starting point for further functionalization reactions, the high reactivity of this surface toward a simple polar molecule such as ammonia still remains unclear. We therefore undertook a comprehensive investigation of the factors that govern the reactivity of halogenated silicon surfaces. The reaction of NH3 was investigated comparatively on the Cl-Si(100)-2 × 1, Br-Si(100)-2 × 1, H-Si(100)-2 × 1, and Si(100)-2 × 1 surfaces using density functional theory. The halogenated surfaces show considerable activation with respect to the hydrogenated surface. The reaction on the halogenated surfaces proceeds via the formation of a stable datively bonded complex in which a silicon atom is pentacoordinated. The activation of the halogenated Si(100)-2 × 1 surfaces toward ammonia arises from the large redistribution of charge in the transition state that precedes the breakage of the Si-X bond and the formation of the Si-NH2 bond. This transition state has an ionic nature of the form Si-NH3(+)X(-). Steric effects also play an important role in surface reactivity, making brominated surfaces less reactive than chlorinated surfaces. The overall activation-energy barriers on the Cl-Si(100)-2 × 1 and Br-Si(100)-2 × 1 surfaces are 12.3 and 19.9 kcal/mol, respectively, whereas on the hydrogenated Si(100)-2 × 1 surface the energy barrier is 38.3 kcal/mol. The reaction of ammonia on the chlorinated surface is even more activated than on the bare Si(100)-2 × 1 surface, for which the activation barrier is 21.3 kcal/mol. Coadsorption effects in partially aminated surfaces and in the presence of reaction products increase activation-energy barriers and have a blocking effect for further reactions of NH3.
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Affiliation(s)
- Federico A Soria
- Departamento de Fisicoquímica and ‡Departamento de Matemática y Física, Facultad de Ciencias Químicas and Instituto de Investigaciones en Fisicoquímica de Córdoba (INFIQC), Universidad Nacional de Córdoba , Córdoba, Argentina
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165
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Li Y, Wang J, Cai C. Rapid grafting of azido-labeled oligo(ethylene glycol)s onto an alkynyl-terminated monolayer on nonoxidized silicon via microwave-assisted "click" reaction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:2437-45. [PMID: 21306165 PMCID: PMC3102157 DOI: 10.1021/la104060j] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Microwave (MW) irradiation was used for the grafting of azido-labeled oligo(ethylene oxide) (OEG) on alkynyl-terminated nonoxidized silicon substrates via copper-catalyzed "click" reaction. The "clickable" monolayers were prepared by photografting of an α,ω-alkynene, where the alkynyl terminus was protected by a trimethylgermanyl (TMG) group, onto hydrogen-terminated Si(111) surfaces. X-ray photoelectron spectroscopy (XPS) was primarily employed to characterize the monolayers, and the data obtained were utilized to calculate the surface density of the TMG-alkynyl-functionalized substrate. MW-assisted one-pot deprotection/click reaction was optimized on the surfaces using azido-tagged OEG derivatives. Using MW instead of conventional heating led to a substantial improvement in the rate of the reaction while suppressing the oxidation of the silicon interface and OEG degradation. The antifouling property of the resulting substrates was evaluated using fibrinogen as a model protein. Results show that the OEG-modification reduced the protein adsorption by >90%.
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Affiliation(s)
| | | | - Chengzhi Cai
- Department of Chemistry, University of Houston, Houston, TX, 77204
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166
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Rosso M, Nguyen AT, de Jong E, Baggerman J, Paulusse JMJ, Giesbers M, Fokkink RG, Norde W, Schroën K, van Rijn CJM, Zuilhof H. Protein-repellent silicon nitride surfaces: UV-induced formation of oligoethylene oxide monolayers. ACS APPLIED MATERIALS & INTERFACES 2011; 3:697-704. [PMID: 21309535 DOI: 10.1021/am100985c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The grafting of polymers and oligomers of ethylene oxide onto surfaces is widely used to prevent nonspecific adsorption of biological material on sensors and membrane surfaces. In this report, we show for the first time the robust covalent attachment of short oligoethylene oxide-terminated alkenes (CH(3)O(CH(2)CH(2)O)(3)(CH(2))(11)-(CH═CH(2)) [EO(3)] and CH(3)O(CH(2)CH(2)O)(6)(CH(2))(11)-(CH═CH(2)) [EO(6)]) from the reaction of alkenes onto silicon-rich silicon nitride surfaces at room temperature using UV light. Reflectometry is used to monitor in situ the nonspecific adsorption of bovine serum albumin (BSA) and fibrinogen (FIB) onto oligoethylene oxide coated silicon-rich silicon nitride surfaces (EO(n)-Si(x)N(4), x > 3) in comparison with plasma-oxidized silicon-rich silicon nitride surfaces (SiO(y)-Si(x)N(4)) and hexadecane-coated Si(x)N(4) surfaces (C(16)-Si(x)N(4)). A significant reduction in protein adsorption on EO(n)-Si(x)N(4) surfaces was achieved, adsorption onto EO(3)-Si(x)N(4) and EO(6)-Si(x)N(4) were 0.22 mg m(-2) and 0.08 mg m(-2), respectively. The performance of the obtained EO(3) and EO(6) layers is comparable to those of similar, highly protein-repellent monolayers formed on gold and silver surfaces. EO(6)-Si(x)N(4) surfaces prevented significantly the adsorption of BSA (0.08 mg m(-2)). Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), X-ray reflectivity and static water contact angle measurements were employed to characterize the modified surfaces. In addition, the stability of EO(6)-Si(x)N(4) surfaces in phosphate-buffered saline solution (PBS) and alkaline condition (pH 10) was studied. Prolonged exposure of the surfaces to PBS solution for 1 week or alkaline condition for 2 h resulted in only minor degradation of the ethylene oxide moieties and no oxidation of the Si(x)N(4) substrates was observed. Highly stable antifouling coatings on Si(x)N(4) surfaces significantly broaden the application potential of silicon nitride-coated microdevices, and in particular of microfabricated filtration membranes.
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Affiliation(s)
- Michel Rosso
- Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands
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167
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Guan B, Ciampi S, Le Saux G, Gaus K, Reece PJ, Gooding JJ. Different functionalization of the internal and external surfaces in mesoporous materials for biosensing applications using "click" chemistry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:328-334. [PMID: 21141983 DOI: 10.1021/la102599m] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report the use of copper(I)-catalyzed alkyne-azide cycloaddition reaction (CuAAC) to selectively functionalize the internal and external surfaces of mesoporous materials. Porous silicon rugate filters with narrow line width reflectivity peaks were employed to demonstrate this selective surface functionalization approach. Hydrosilylation of a dialkyne species, 1,8-nonadiyne, was performed to stabilize the freshly fabricated porous silicon rugate filters against oxidation and to allow for further chemical derivatization via "click" CuAAC reactions. The external surface was modified through CuAAC reactions performed in the absence of nitrogen-based Cu(I)-stabilizing species (i.e., ligand-free reactions). To subsequently modify the interior pore surface, stabilization of the Cu(I) catalyst was required. Optical reflectivity measurements, water contact angle measurements, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were used to demonstrate the ability of the derivatization approach to selectively modify mesoporous materials with different surface chemistry on the exterior and interior surfaces. Furthermore, porous silicon rugate filters modified externally with the cell-adhesive peptide Gly-Arg-Gly-Asp-Ser (GRGDS) allowed for cell adhesion via formation of focal adhesion points. Results presented here demonstrate a general approach to selectively modify mesoporous silicon samples with potential applications for cell-based biosensing.
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Affiliation(s)
- Bin Guan
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
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168
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Ciampi S, James M, Darwish N, Luais E, Guan B, Harper JB, Gooding JJ. Oxidative acetylenic coupling reactions as a surface chemistry tool. Phys Chem Chem Phys 2011; 13:15624-32. [DOI: 10.1039/c1cp21450k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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169
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Lavi A, Cohen H, Bendikov T, Vilan A, Cahen D. Si–C-bound alkyl chains on oxide-free Si: towards versatile solution preparation of electronic transport quality monolayers. Phys Chem Chem Phys 2011; 13:1293-6. [PMID: 21132168 DOI: 10.1039/c0cp01445a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Avi Lavi
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
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170
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Hsu SH, Reinhoudt DN, Huskens J, Velders AH. Lateral interactions at functional monolayers. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c0jm02696d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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171
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Collins G, Holmes JD. Chemical functionalisation of silicon and germanium nanowires. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm11028d] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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172
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Bélanger D, Pinson J. Electrografting: a powerful method for surface modification. Chem Soc Rev 2011; 40:3995-4048. [DOI: 10.1039/c0cs00149j] [Citation(s) in RCA: 751] [Impact Index Per Article: 57.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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173
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Gooding JJ, Ciampi S. The molecular level modification of surfaces: from self-assembled monolayers to complex molecular assemblies. Chem Soc Rev 2011; 40:2704-18. [DOI: 10.1039/c0cs00139b] [Citation(s) in RCA: 390] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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174
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Fabre B. Ferrocene-terminated monolayers covalently bound to hydrogen-terminated silicon surfaces. Toward the development of charge storage and communication devices. Acc Chem Res 2010; 43:1509-18. [PMID: 20949977 DOI: 10.1021/ar100085q] [Citation(s) in RCA: 173] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The combination of monocrystalline silicon's well-defined structure and the ability to prepare hydrogen-terminated surfaces (Si-H) easily and reproducibly has made this material a very attractive substrate for immobilizing functional molecules. The functionalization of Si-H using the covalent attachment of organic monolayers has received intense attention due to the numerous potential applications of controlled and robust organic/Si interfaces. Researchers have investigated these materials in diverse fields such as molecular electronics, chemistry, and bioanalytical chemistry. Applications include the preparation of surface insulators, the incorporation of chemical or biochemical functionality at interfaces for use in photovoltaic conversion, and the development of new chemical and biological sensing devices. Unlike those of gold, silicon's electronic properties are tunable, and researchers can directly integrate silicon-based devices within electronic circuitry. Moreover, the technological processes used for the micro- and nanopatterning of silicon are numerous and mature enough for producing highly miniaturized functional electronic components. In this Account, we describe a powerful approach that integrates redox-active molecules, such as ferrocene, onto silicon toward electrically addressable systems devoted to information storage or transfer. Ferrocene exhibits attractive electrochemical characteristics: fast electron-transfer rate, low oxidation potential, and two stable redox states (neutral ferrocene and oxidized ferrocenium). Accordingly, ferrocene-modified silicon surfaces could be used as charge storage components with the bound ferrocene center as the memory element. Upon application of a positive potential to silicon, ferrocene is oxidized to its corresponding ferrocenium form. This redox change is equivalent to the change of a bit of information from the "0" to "1" state. To erase the stored charge and return the device to its initial state, a low potential must be applied to reduce the whole generated ferrocenium. In this type of application, the electron is transferred from the ferrocene headgroups to the underlying conducting silicon surface by a tunneling process across the monolayer. To produce a stable and reproducible electrical response, this process must be efficient, fast, and reversible. The stability, charge density, and capacitance performances of high-quality ferrocene-terminated monolayers could compete with those of the existing semiconductor-based memory devices, such as dynamic random access memories, DRAMs. Moreover, we provide experimental evidence that a series of immobilized ferrocene centers can efficiently communicate via a lateral electron hopping process. Using these modified interfaces, we demonstrate that the thin redox-active monolayer can behave as a purely conducting material, highlighting an unprecedented very fast electron communication between immobilized redox groups. Perhaps more importantly, the surface coverage of ferrocene allows us to precisely control the rate of this process. Such characteristics are relevant not only for electrocatalytic reactions but also for widening the potential applications of these assemblies to novel molecular electronic devices (e.g. chemiresistors, chemically sensitive field-effect transistors (CHEMFETs)) and redox chemistry on insulating surfaces.
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Affiliation(s)
- Bruno Fabre
- CNRS UMR 6226, Sciences Chimiques de Rennes, Matière Condensée et Systèmes Electroactifs (MaCSE), Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex, France
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175
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Qin G, Santos C, Zhang W, Li Y, Kumar A, Erasquin UJ, Liu K, Muradov P, Trautner BW, Cai C. Biofunctionalization on alkylated silicon substrate surfaces via "click" chemistry. J Am Chem Soc 2010; 132:16432-41. [PMID: 21033708 PMCID: PMC3059218 DOI: 10.1021/ja1025497] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Biofunctionalization of silicon substrates is important to the development of silicon-based biosensors and devices. Compared to conventional organosiloxane films on silicon oxide intermediate layers, organic monolayers directly bound to the nonoxidized silicon substrates via Si-C bonds enhance the sensitivity of detection and the stability against hydrolytic cleavage. Such monolayers presenting a high density of terminal alkynyl groups for bioconjugation via copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC, a "click" reaction) were reported. However, yields of the CuAAC reactions on these monolayer platforms were low. Also, the nonspecific adsorption of proteins on the resultant surfaces remained a major obstacle for many potential biological applications. Herein, we report a new type of "clickable" monolayers grown by selective, photoactivated surface hydrosilylation of α,ω-alkenynes, where the alkynyl terminal is protected with a trimethylgermanyl (TMG) group, on hydrogen-terminated silicon substrates. The TMG groups on the film are readily removed in aqueous solutions in the presence of Cu(I). Significantly, the degermanylation and the subsequent CuAAC reaction with various azides could be combined into a single step in good yields. Thus, oligo(ethylene glycol) (OEG) with an azido tag was attached to the TMG-alkyne surfaces, leading to OEG-terminated surfaces that reduced the nonspecific adsorption of protein (fibrinogen) by >98%. The CuAAC reaction could be performed in microarray format to generate arrays of mannose and biotin with varied densities on the protein-resistant OEG background. We also demonstrated that the monolayer platform could be functionalized with mannose for highly specific capturing of living targets (Escherichia coli expressing fimbriae) onto the silicon substrates.
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176
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Tuning the reactivity of semiconductor surfaces by functionalization with amines of different basicity. Proc Natl Acad Sci U S A 2010; 108:956-60. [PMID: 21068370 DOI: 10.1073/pnas.1006656107] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Surface functionalization of semiconductors has been the backbone of the newest developments in microelectronics, energy conversion, sensing device design, and many other fields of science and technology. Over a decade ago, the notion of viewing the surface itself as a chemical reagent in surface reactions was introduced, and adding a variety of new functionalities to the semiconductor surface has become a target of research for many groups. The electronic effects on the substrate have been considered as an important consequence of chemical modification. In this work, we shift the focus to the electronic properties of the functional groups attached to the surface and their role on subsequent reactivity. We investigate surface functionalization of clean Si(100)-2 × 1 and Ge(100)-2 × 1 surfaces with amines as a way to modify their reactivity and to fine tune this reactivity by considering the basicity of the attached functionality. The reactivity of silicon and germanium surfaces modified with ethylamine (CH(3)CH(2)NH(2)) and aniline (C(6)H(5)NH(2)) is predicted using density functional theory calculations of proton attachment to the nitrogen of the adsorbed amine to differ with respect to a nucleophilic attack of the surface species. These predictions are then tested using a model metalorganic reagent, tetrakis(dimethylamido)titanium (((CH(3))(2)N)(4)Ti, TDMAT), which undergoes a transamination reaction with sufficiently nucleophilic amines, and the reactivity tests confirm trends consistent with predicted basicities. The identity of the underlying semiconductor surface has a profound effect on the outcome of this reaction, and results comparing silicon and germanium are discussed.
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177
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Kelly JA, Veinot JGC. An investigation into near-UV hydrosilylation of freestanding silicon nanocrystals. ACS NANO 2010; 4:4645-4656. [PMID: 20731446 DOI: 10.1021/nn101022b] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We present a study of the photochemical hydrosilylation of freestanding silicon nanocrystals (Si-NCs) using a near-UV source. The impact of reaction with alkenes and alkynes was studied using in situ photoluminescence (PL) spectroscopy, allowing measurement of both changes in intensity and PL maxima during the reaction. Understanding this behavior is important for the utilization of these materials in a number of applications where hydrosilylation is a leading method to functionalize Si-NCs. Changes in the PL were studied and shown arise from the influence of oxidation as well as the Si-C bond formation. Hydrosilylation with a range of conjugated alkynyl species was studied to understand how the introduction of these species to the NC surface can quench the PL from Si-NCs. These results were explained in context of the free-radical and exciton-mediated mechanisms for photochemical hydrosilylation proposed for Si-NCs. Materials in this study were characterized by Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM), selected electron area diffraction (SAED), energy dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA) and dynamic light scattering (DLS).
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Affiliation(s)
- Joel A Kelly
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
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Fukumitsu H, Masuda T, Qu D, Waki Y, Noguchi H, Shimazu K, Uosaki K. Novel Method for Construction of a Metal–Organic Monolayer–Si Structure Utilizing Thiol-terminated Monolayer Covalently Bonded to the Surface through Si–C Bonds. CHEM LETT 2010. [DOI: 10.1246/cl.2010.768] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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