Covalent Attachment of Cell-Adhesive, (Arg-Gly-Asp)-Containing Peptides to Titanium Surfaces

Titanium (Ti) dental implants have been used widely for many years. Long term implant failures are related, in part, to the development of peri-implantitis frequently associated with bacteria. Bacterial adherence and colonization have been considered a key factor in the pathogenesis of many biomaterial based infections. Without the initial attachment of oral bacteria to Ti-implant surfaces, subsequent polymicrobial accumulation and colonization leading to peri-implant disease cannot occur. The overall goal of this study is to examine the implant-oral bacterial interfaces and gain a greater understanding of their attachment characteristics and mechanisms. Since the detailed cell surface ultrastructure involved in attachment is only discernible at the electron microscopy level, the study is complicated by the technical problem of obtaining titanium implant and attached bacterial cells in the same ultra-thin sections. In this study, a technique was developed to facilitate the study of Ti implant-bacteria interface.Discs of polymerized Spurr’s resin (12 mm x 5 mm) were formed to a thickness of approximately 3 mm using an EM block holder (Fig. 1). Titanium was then deposited by vacuum deposition to a film thickness of 300Å (Fig. 2).

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ROLE OF rhBMP-2 AND rhBMP-7 IN THE METABOLISM AND DIFFERENTIATION OF OSTEOBLAST-LIKE CELLS CULTURED ON CHEMICALLY MODIFIED TITANIUM SURFACES

Journal of Oral Implantology ◽

10.1563/aaid-joi-d-12-00071.1 ◽

2012 ◽

pp. 141208072802005

Author(s):

Fabiano Ribeiro Cirano ◽

ADRIANE TOGASHI ◽

MARCIA MARQUES ◽

FRANCISCO PUSTIGLIONI ◽

LUIZ LIMA

Keyword(s):

Chemically Modified ◽

Titanium Surfaces ◽

Cells Cultured

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Photochemical and Electrochemical Reduction of Carbon Dioxide Catalyzed by a Polyoxometalate-Organic Photosensitizer Complex

10.26434/chemrxiv.7177892 ◽

2018 ◽

Author(s):

Chandan Dey ◽

Ronny Neumann

Keyword(s):

Carbon Dioxide ◽

Cyclic Voltammetry ◽

Formic Acid ◽

Electrochemical Reduction ◽

Mass Spectroscopy ◽

Photochemical Reactions ◽

Reducing Agent ◽

Covalent Attachment ◽

Hybrid Complex ◽

Open Face

A manganese substituted Anderson type polyoxometalate, [MnMo6O24]9-, tethered with an anthracene photosensitizer was prepared and used as catalyst for CO2 reduction. The polyoxometalate-photosensitizer hybrid complex, obtained by covalent attachment of the sensitizer to only one face of the planar polyoxometalate, was characterized by NMR, IR and mass spectroscopy. Cyclic voltammetry measurements show a catalytic response for the reduction of carbon dioxide, thereby suggesting catalysis at the manganese site on the open face of the polyoxometalate. Controlled potentiometric electrolysis showed the reduction of CO2 to CO with a TOF of ~15 sec-1. Further photochemical reactions showed that the polyoxometalate-anthracene hybrid complex was active for the reduction of CO2 to yield formic acid and/or CO in varying amounts dependent on the reducing agent used. Control experiments showed that the attachment of the photosensitizer to [MnMo6O24]9- is necessary for photocatalysis.<div> </div>

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Site-Specific Protein Covalent Attachment to Nanotubes and Its Electronic Impact on Single Molecule Function

10.26434/chemrxiv.7798973.v1 ◽

2019 ◽

Author(s):

Adam Beachey ◽

Harley Worthy ◽

William David Jamieson ◽

Suzanne Thomas ◽

Benjamin Bowen ◽

...

Keyword(s):

Single Molecule ◽

Fluorescent Protein ◽

Functional Integration ◽

Attachment Site ◽

Covalent Attachment ◽

Great Promise ◽

Functional Coupling ◽

Phenyl Azide ◽

Electronic Impact ◽

Protein Attachment

Functional integration of proteins with carbon-based nanomaterials such as nanotubes holds great promise in emerging electronic and optoelectronic applications. Control over protein attachment poses a major challenge for consistent and useful device fabrication, especially when utilizing single/few molecule properties. Here, we exploit genetically encoded phenyl azide photochemistry to define the direct covalent attachment of three different proteins, including the fluorescent protein GFP, to carbon nanotube side walls. Single molecule fluorescence revealed that on attachment to SWCNTs GFP’s fluorescence changed in terms of intensity and improved resistance to photobleaching; essentially GFP is fluorescent for much longer on attachment. The site of attachment proved important in terms of electronic impact on GFP function, with the attachment site furthest from the functional center having the larger effect on fluorescence. Our approach provides a versatile and general method for generating intimate protein-CNT hybrid bioconjugates. It can be potentially applied easily to any protein of choice; attachment position and thus interface characteristics with the CNT can easily be changed by simply placing the phenyl azide chemistry at different residues by gene mutagenesis. Thus, our approach will allow consistent construction and modulate functional coupling through changing the protein attachment position.

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