Impact of chain morphology on the lubricity of surface-grafted polysaccharides

Goren, Tolga; Spencer, Nicholas D.; Crockett, Rowena

doi:10.1039/c4ra01087f

Cited by 17 publications

(20 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Synthetic bottle brushes with hydrophilic side chains and adsorbing main chains self-assemble into nonfouling polymer brushes. 8 , 9 Surface layers of bottle-brush polymers with hydrophilic side chains have very good lubrication properties, 10 especially if the side chains are highly charged. 11 Fredrickson predicted that grafting side chains to a flexible main chain should dramatically increase the effective stiffness of the main chain and lead to the possibility of nematic ordering of bottle-brush polymers.…”

Section: Introductionmentioning

confidence: 99%

Force and Scale Dependence of the Elasticity of Self-Assembled DNA Bottle Brushes

et al. 2017

View full text Add to dashboard Cite

As a model system to study the elasticity of bottle-brush polymers, we here introduce self-assembled DNA bottle brushes, consisting of a DNA main chain that can be very long and still of precisely defined length, and precisely monodisperse polypeptide side chains that are physically bound to the DNA main chains. Polypeptide side chains have a diblock architecture, where one block is a small archaeal nucleoid protein Sso7d that strongly binds to DNA. The other block is a net neutral, hydrophilic random coil polypeptide with a length of exactly 798 amino acids. Light scattering shows that for saturated brushes the grafting density is one side chain per 5.6 nm of DNA main chain. According to small-angle X-ray scattering, the brush diameter is D = 17 nm. By analyzing configurations of adsorbed DNA bottle brushes using AFM, we find that the effective persistence of the saturated DNA bottle brushes is Peff = 95 nm, but from force–extension curves of single DNA bottle brushes measured using optical tweezers we find Peff = 15 nm. The latter is equal to the value expected for DNA coated by the Sso7d binding block alone. The apparent discrepancy between the two measurements is rationalized in terms of the scale dependence of the bottle-brush elasticity using theory previously developed to analyze the scale-dependent electrostatic stiffening of DNA at low ionic strengths.

show abstract

Section: Introductionmentioning

confidence: 99%

Force and Scale Dependence of the Elasticity of Self-Assembled DNA Bottle Brushes

et al. 2017

View full text Add to dashboard Cite

show abstract

“…End-grafted dense polymer films in a good solvent; that is, ''polymer brushes,'' can drastically reduce the CoF between two surfaces in boundary contact. [39][40][41][42][43] The mechanism behind this phenomenon is thought to be the ability of the brush to minimize adhesion forces, providing an elastic resistance to compression, and having a fluid-like interface that can be easily sheared. 44 Indeed, DD_5 had a low CoF in TLF, and in all the TMS formulations lacking borate.…”

Section: Discussionmentioning

confidence: 99%

Friction Measurements on Contact Lenses in a Physiologically Relevant Environment: Effect of Testing Conditions on Friction

Sterner

Aeschlimann

Zürcher

et al. 2016

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

show abstract

“…To assess the response to changes in ionic strength of the grafted pectin layers, the baseline was first recorded in water, then the salt solution was introduced into the QCM-D cell and left to equilibrate for 8 minutes before returning to pure water. The changes in the thickness and viscoelastic properties of the film upon addition of salt were modelled in Excel using a Voigt viscolelastic model 42 .…”

Section: Qcm-dmentioning

confidence: 99%

“…In these examples, the grafting to the surface has been carried out along the whole polysaccharide chain rather than at a single endpoint, thus constraining its conformation and potentially limiting its lubricating ability and responsiveness. Dextran has been grafted at a terminal residue, however, bridging issues between the surfaces caused high friction at high loads [41][42] .…”

Section: Introductionmentioning

confidence: 99%

Responsive polysaccharide-grafted surfaces for biotribological applications

et al. 2019

View full text Add to dashboard Cite

The elucidation of biolubrication mechanisms and the design of artificial biotribological contacts requires the development of model surfaces that can help to tease out the cues that govern friction in biological systems. Polysaccharides provide an interesting option as a biotribological mimic due to their similarity with the glycosylated molecules present at biointerfaces. Here, pectin was successfully covalently grafted at its reducing end to a polydimethylsiloxane (PDMS) surface via a reductive amination reaction. This method enabled the formation of a wear resistant pectin layer that provided enhanced boundary lubrication compared to adsorbed pectin. Pectins with different degrees of methylesterification and blockiness were exposed to salt solutions of varying ionic strength and displayed responsiveness to solvent conditions. Exposure of the grafted pectin layers to solutions of between 1 and 200 mM NaCl resulted in a decrease in boundary friction and an increase in the hydration and swelling of the pectin layer to varying degrees depending on the charge density of the pectin, showing the potential to tune the conformation and friction of the layer using the pectin architecture and environmental cues. The robust and responsive nature of these new pectin grafted surfaces makes them an effective mimic of biotribological interfaces and provides a powerful tool to study the intricate mechanisms involved in the biolubrication phenomenon.

show abstract

Impact of chain morphology on the lubricity of surface-grafted polysaccharides

Abstract: The impact of brush-like structure and disorder on the lubricating ability of dextran chains at low and high loads has been investigated by means of AFM.

Cited by 17 publications

References 38 publications

Force and Scale Dependence of the Elasticity of Self-Assembled DNA Bottle Brushes

Force and Scale Dependence of the Elasticity of Self-Assembled DNA Bottle Brushes

Friction Measurements on Contact Lenses in a Physiologically Relevant Environment: Effect of Testing Conditions on Friction

Responsive polysaccharide-grafted surfaces for biotribological applications

Contact Info

Product

Resources

About