@article {2698,
	title = {Barrier Capacity of Hydrophilic Polymer Brushes To Prevent Hydrophobic Interactions: Effect of Graft Density and Hydrophilicity},
	journal = {Macromolecules},
	volume = {42},
	number = {13},
	year = {2009},
	note = {ISI Document Delivery No.: 472NJTimes Cited: 7Cited Reference Count: 57Zou, Yuquan Rossi, Nicholas A. A. Kizhakkedathu, Jayachandran N. Brooks, Donald E.},
	month = {Jul},
	pages = {4817-4828},
	type = {Article},
	abstract = {The performance of biomaterials in contact with biological systems can be greatly affected by hydrophobic interactions at the interface between the biomaterial surface and surrounding biomolecules. Polymer brushes can function as a protective layer, preventing such interfacial hydrophobic interactions. In this paper, a systematic study of the barrier properties of a hydrophilic polymer brush is made by investigating the influence of graft density and its chemical nature (hydrophilicity/hydrophobicity) on hydrophobic interactions with the surface. To achieve this, it series of novel thermoresponsive poly-N-[(2,2-dimethyl-1,3-dioxolane)methyl]acrylamide (PDMDOMA) polymer brushes were grown from silicon wafers via surface-initiated atom transfer radical polymerization. Without changing graft density or degree of polymerization, the hydrophilicity of the PDMDOMA brushes was manipulated by partial or complete hydrolysis or the pendent dioxolane moieties. A lower critical solution temperature (LCST) was observed at 22-24 degrees C, below which the PDMDOMA brush was Found to be in a hydrated state (amphiphilic), while at temperatures above the LCST, the PDMDOMA brush formed a collapsed. more hydrophobic structure. A physical method was developed to analyze the ability of these brushes to act as a barrier against hydrophobic interactions based on AFM force-distance measurements. The adhesive forces between the Si3N4 tip and the silicon wafer surface upon (a) modification with ATRP initiator, (b) grafting of PDMDOMA brushes, and (c) partial and complete hydrolysis of PDMDOMA were investigated. Hydrophobic interactions decreased after each modification, while graft density and the degree of hydrolysis increased the barrier function of the surface layer. In particular, when graft density was above 0.22 chains/nm(2), the barrier capacity completely counteracted the hydrophobic interactions, as evidenced from the disappearance of the adhesive force in AFM measurements. Further Studies revealed that the barrier property its assessed by AFM correlated well with the wettability of the surfaces.},
	keywords = {ATOMIC-FORCE MICROSCOPY, BLOOD-PLASMA, CELL-ADHESION, CHAIN-LENGTH, HUMAN, MOLECULAR-WEIGHT, protein adsorption, SERUM-ALBUMIN, SINGLE-MOLECULE, SURFACE, TRANSFER RADICAL POLYMERIZATION},
	isbn = {0024-9297},
	url = {<Go to ISI>://000268138500067},
	author = {Zou, Y. Q. and Rossi, N. A. A. and Kizhakkedathu, J. N. and Brooks, D. E.}
}
@article {2697,
	title = {Surface Modification of Polyvinyl Chloride Sheets via Growth of Hydrophilic Polymer Brushes},
	journal = {Macromolecules},
	volume = {42},
	number = {9},
	year = {2009},
	note = {ISI Document Delivery No.: 441PNTimes Cited: 7Cited Reference Count: 65Zou, Yuquan Kizhakkedathu, Jayachandran N. Brooks, Donald E.},
	month = {May},
	pages = {3258-3268},
	type = {Article},
	abstract = {Poly(N,N-dimethylacrylamide) (PDMA) brushes were successfully grown from polyvinyl chloride (uPVC) sheets via well-controlled surface-initiated atom transfer radical polymerization (SI-ATRP). An ATRP initiator containing a chloropropionate moiety was chemically tethered onto the surface of PVC via it novel wet chemical modification. Negatively charged sulfate groups were introduced to facilitate polymerization. By incorporating a chemically cleavable group into the initiator, molecular weight, polydispersity and graft density of a series of PDMA brushes synthesized on the flat surface were unambiguously characterized for the first time by gel permeation chromatography. ATR-FTIR, contact angle, SEM and AFM were used to characterize the PDMA grafted surfaces. Reaction conditions Such as monomer concentration, reaction time, copper(II) concentration and salt additives were varied to systematically investigate their effects on molecular weight and graft density of the PDMA grafted from PVC. Molecular weights of grafted PDMA brushes varied from ca. 20 000 to 2 170 000 Da, while craft density ranged from 0.08 to 1.13 chains/nm(2). Polydispersity of grafted PDMA brushes was controlled between 1.20 and 1.60 by Cu(II) complex addition. Kinetic studies revealed that the surface initiation was a slow process and graft density increased during the reaction. The brush uniformity increased with increasing reaction time. Reinitiation of the obtained PDMA brushes was demonstrated, suggesting that the polymerization is "living". The successful growth of a PDMA-b-poly(N-isopropylacrylamide) (PNIPAM) copolymer brush was verified by GPC and AFM.},
	keywords = {AQUEOUS ATRP, ATOMIC-FORCE MICROSCOPY, CARBON NANOTUBES, COPOLYMER BRUSHES, density, GLYCOL), GRAFT, PLASMA-PROTEIN ADSORPTION, POLY(ETHYLENE, SELF-ASSEMBLED MONOLAYERS, SERUM-ALBUMIN, TRANSFER RADICAL POLYMERIZATION},
	isbn = {0024-9297},
	url = {<Go to ISI>://000265781300007},
	author = {Zou, Y. Q. and Kizhakkedathu, J. N. and Brooks, D. E.}
}
@article {2148,
	title = {{\textquoteright}Mechanical Engineering{\textquoteright} of Elastomeric Proteins: Toward Designing New Protein Building Blocks for Biomaterials},
	journal = {Advanced Functional Materials},
	volume = {18},
	number = {18},
	year = {2008},
	note = {ISI Document Delivery No.: 358QQTimes Cited: 6Cited Reference Count: 102Li, Hongbin},
	month = {Sep},
	pages = {2643-2657},
	type = {Review},
	abstract = {Elastomeric proteins are subject to stretching force under biological settings and play important roles in regulating the mechanical properties of a wide range of biological machinery. Elastomeric proteins also underlie the superb mechanical properties of many protein-based biomaterials. The developments of single molecule force spectroscopy have enabled the direct characterization of the mechanical properties of elastomeric proteins at the single molecule level and led to the new burgeoning field of research: single protein mechanics-and engineering. Combined, single molecule atomic force microscopy and protein engineering efforts are well under way to understand molecular determinants for the mechanical stability of elastomeric proteins and to develop methodologies to tune the mechanical properties of proteins in a rational and systematic fashion, which will lead to the {\textquoteright}mechanical engineering{\textquoteright} of elastomeric proteins. Here the current status of these experimental efforts is discussed and the successes and challenges in constructing novel proteins with tailored nanomechanical proteins are highlighted. The prospect of employing such engineered artificial elastomeric proteins as building blocks for the construction of biomaterials for applications ranging from material sciences to biomedical engineering is also discussed.},
	keywords = {ATOMIC-FORCE MICROSCOPY, BIOLOGICAL ROLES, DIHYDROFOLATE-REDUCTASE, EXTRACELLULAR-MATRIX PROTEIN, FLUORESCENT PROTEIN, IG DOMAIN, MOLECULAR-DYNAMICS SIMULATIONS, PROTEIN, SINGLE, TITIN IMMUNOGLOBULIN DOMAINS, UNFOLDING PATHWAYS},
	isbn = {1616-301X},
	url = {<Go to ISI>://000259933000001},
	author = {Li, H. B.}
}
@article {2017,
	title = {Recombination of protein fragments: A promising approach toward engineering proteins with novel nanomechanical properties},
	journal = {Protein Science},
	volume = {17},
	number = {10},
	year = {2008},
	note = {ISI Document Delivery No.: 351CKTimes Cited: 4Cited Reference Count: 50Balamurali, M. M. Sharma, Deepak Chang, Anderson Khor, Dingyue Chu, Ricky Li, Hongbin},
	month = {Oct},
	pages = {1815-1826},
	type = {Article},
	abstract = {Combining single molecule atomic force microscopy (AFM) and protein engineering techniques, here we demonstrate that we can use recombination-based techniques to engineer novel elastomeric proteins by recombining protein fragments from structurally homologous parent proteins. Using I27 and I32 domains from the muscle protein titin as parent template proteins, we systematically shuffled the secondary structural elements of the two parent proteins and engineered 13 hybrid daughter proteins. Although I27 and I32 are highly homologous, and homology modeling predicted that the hybrid daughter proteins fold into structures that are similar to that of parent protein, we found that only eight of the 13 daughter proteins showed beta-sheet dominated structures that are similar to parent proteins, and the other five recombined proteins showed signatures of the formation of significant alpha-helical or random coil-like structure. Single molecule AFM revealed that six recombined daughter proteins are mechanically stable and exhibit mechanical properties that are different from the parent proteins. In contrast, another four of the hybrid proteins were found to be mechanically labile and unfold at forces that are lower than the similar to 20 pN, as we could not detect any unfolding force peaks. The last three hybrid proteins showed interesting duality in their mechanical unfolding behaviors. These results demonstrate the great potential of using recombination-based approaches to engineer novel elastomeric protein domains of diverse mechanical properties. Moreover, our results also revealed the challenges and complexity of developing a recombination-based approach into a laboratory-based directed evolution approach to engineer novel elastomeric proteins.},
	keywords = {ATOMIC-FORCE MICROSCOPY, BIOLOGICAL ROLES, COMPUTATIONAL DESIGN, ELASTICITY, elastomeric protein, EVOLUTION, IMMUNOGLOBULIN DOMAINS, MECHANICAL STABILITY, mechanical unfolding, MOLECULAR-DYNAMICS SIMULATION, recombination, SEQUENCE, SINGLE PROTEIN, single-molecule force spectroscopy, TITIN},
	isbn = {0961-8368},
	url = {<Go to ISI>://000259401900019},
	author = {Balamurali, M. M. and Sharma, D. and Chang, A. and Khor, D. and Chu, R. and Li, H. B.}
}
@article {1555,
	title = {Engineering proteins with novel mechanical properties by recombination of protein fragments},
	journal = {Angewandte Chemie-International Edition},
	volume = {45},
	number = {34},
	year = {2006},
	note = {ISI Document Delivery No.: 082MRTimes Cited: 20Cited Reference Count: 51Sharma, Deepak Cao, Yi Li, Hongbin},
	pages = {5633-5638},
	type = {Article},
	keywords = {AFM, ATOMIC-FORCE MICROSCOPY, ELASTICITY, EVOLUTION, IG DOMAIN, IMMUNOGLOBULIN DOMAINS, MOLECULAR-DYNAMICS SIMULATIONS, protein engineering, protein structures, scanning probe microscopy, SINGLE PROTEIN, single-molecule studies, SPECTROSCOPY, STABILITY, TITIN},
	isbn = {1433-7851},
	url = {<Go to ISI>://000240391400016},
	author = {Sharma, D. and Cao, Y. and Li, H. B.}
}
@inbook {1447,
	title = {Surface science studies of the effect of Al alloy microstructure on the formation of chromate coatings},
	booktitle = {Aluminium Alloys 2006, Pts 1 and 2 - Research through Innovation and Technology},
	series = {Materials Science Forum},
	volume = {519-521},
	year = {2006},
	note = {ISI Document Delivery No.: BEZ41Times Cited: 3Cited Reference Count: 22Kulinich, S. A. Akhtar, A. S. Susac, D. Wong, K. C. Wong, P. C. Mitchell, K. A. R.Proceedings Paper10th International Conference on Aliminium Alloys (ICAA-10)JUL 09-13, 2006Vancouver, CANADABRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND},
	pages = {621-628},
	publisher = {Trans Tech Publications Ltd},
	organization = {Trans Tech Publications Ltd},
	address = {Zurich-Uetikon},
	abstract = {Surface science methods including scanning Auger microscopy (SAM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy have been used to study the initial growth of chromate conversion coatings on aluminum 2024-T3 alloy, using a coating bath formed by dissolving CrO3, Na2Cr2O7 and NaF in water. The objective is to learn more about growth mechanism on the different microstructural regions of this alloy surface, including the second-phase particles and the alloy matrix.},
	keywords = {2024-T3 ALUMINUM-ALLOY, AA2024-T3, aluminum alloy, ATOMIC-FORCE MICROSCOPY, CHEMISTRY, chromate conversion coating, CONVERSION COATINGS, corrosion, NUCLEATION, PAINT ADHESION, photoelectron, Raman spectroscopy, scanning Auger microscopy, scanning electron microscopy, SPECTROSCOPY},
	isbn = {0255-54760-87849-408-1},
	url = {<Go to ISI>://000240309000097},
	author = {Kulinich, S. A. and Akhtar, A. S. and Susac, D. and Wong, K. C. and Wong, P. C. and Mitchell, K. A. R.},
	editor = {Poole, W. J. and Wells, M. A. and Lloyd, D. J.}
}
@article {1000,
	title = {Microstructural effects on the initiation of zinc phosphate coatings on 2024-T3 aluminum alloy},
	journal = {Applied Surface Science},
	volume = {239},
	number = {1},
	year = {2004},
	note = {ISI Document Delivery No.: 871NRTimes Cited: 22Cited Reference Count: 67},
	month = {Dec},
	pages = {45-59},
	type = {Article},
	abstract = {The initiation of coatings deposited on to 2024-T3 aluminum alloy from supersaturated zinc phosphating solutions has been studied using scanning Auger microscopy (SAM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The alloy microstructure, especially associated with the second-phase particles, strongly affects the formation stages of the coating process, where etching of the substrate has a significant role. At the start, zinc phosphate (ZPO) crystals form on the Al-Cu-Mg second-phase particles, rather than on the matrix or on the Al-Cu-Fe-Mn particles, with the initial nucleation appearing at interfaces between Al-Cu-Mg particles and the matrix. In contrast, the formation of the ZPO coating is delayed on the cathodic Al-Cu-Fe-Mn particles, compared to those of the Al-Cu-Mg composition. When the coating process is completed, the whole sample surface is covered with ZPO although its thickness varies at the different micro-regions. (C) 2004 Elsevier B.V. All rights reserved.},
	keywords = {7075-T6, AA2024-T3, aluminum alloy, ATOMIC-FORCE MICROSCOPY, CONVERSION COATINGS, ELECTRON-MICROSCOPY, INTERGRANULAR CORROSION, LOCALIZED CORROSION, PERCENT CU ALLOY, phosphating, PITTING CORROSION, SAM, SEM, surface microstructure, TITANIUM PHOSPHATE, XPS},
	isbn = {0169-4332},
	url = {<Go to ISI>://000225140900007},
	author = {Susac, D. and Sun, X. and Li, R. Y. and Wong, K. C. and Wong, P. C. and Mitchell, K. A. R. and Champaneria, R.}
}
@article {909,
	title = {Synthesis and characterization of well-defined hydrophilic block copolymer brushes by aqueous ATRP},
	journal = {Polymer},
	volume = {45},
	number = {22},
	year = {2004},
	note = {ISI Document Delivery No.: 862NOTimes Cited: 27Cited Reference Count: 79},
	month = {Oct},
	pages = {7471-7489},
	type = {Article},
	abstract = {Homopolymer brushes of poly(N,N-dimethylacrylamide) (PDMA), poly(methoxyethylacrylamide) (PMEA) and poly(N-isopropylacrylamide)(PNIPAM) grown on atom transfer radical polymerization (ATRP) initiator functionalized latex particles were used as macroinitiators for the synthesis of PDMA-b-PNIPAM/PMEA, PMEA-b-PDMA/PNIPAM and PNIPAM-b-PDMA block copolymer brushes by surface initiated aqueous ATRP. The grafted homopolymer and block copolymer brushes were analyzed for molecular weight, molecular weight distribution, chain grafting density, composition and hydrodynamic thickness (HT) using gel permeation chromatography-multi-angle laser light scattering, H-1 NMR, particle size analysis and atomic force microscopy (AFM) techniques. The measured graft molecular weight increased following the second ATRP reaction in all cases, indicating the second block had been added. Chain growth depended on the nature of the monomer used for block copolymerization and its concentration. Unimodal distribution of polymer chains in GPC with non-overlap of molar mass-elution volume curves implied an efficient block copolymerization. This was supported by the increase in HT measured by particle size analysis, equilibrium thickness observed by AFM and the composition of the block copolymer layer by H-1 NMR analysis, both in situ and on cleaved chains in solution. 1H NMR analysis of the grafted latex and cleaved polymers from the surface demonstrated that accurate determination of the copolymer composition by this method is possible without detaching polymer chains from surface. Block copolymer brushes obey the same power law dependence of HT on molecular weight as homopolymer brushes in good solvent conditions. The NIPAM-containing block copolymer brushes were sensitive to changes in the environment as shown by a decrease in HT with increase in the temperature of the medium. (C) 2004 Elsevier Ltd. All rights reserved.},
	keywords = {AMBIENT-TEMPERATURE, aqueous atom transfer radical polymerization, ATOMIC-FORCE MICROSCOPY, BRUSHES, CONTROLLED GROWTH, hydrophilic diblock copolymers, LIGHT-SCATTERING, METHYL-METHACRYLATE, N-DIMETHYLACRYLAMIDE), POLY(N, POLYELECTROLYTE BRUSHES, POLYMER BRUSHES, SELF-ASSEMBLED MONOLAYERS, SIZE-EXCLUSION CHROMATOGRAPHY, TRANSFER RADICAL POLYMERIZATION},
	isbn = {0032-3861},
	url = {<Go to ISI>://000224497900011},
	author = {Kizhakkedathu, J. N. and Kumar, K. R. and Goodman, D. and Brooks, D. E.}
}
