Interactions of poly(amino acids) in aqueous solution with charged model surfaces - Analysis by colloidal probe

Gregory S Watson; Jolanta A Blach; C Cahill; D V Nicolau; D K Pham; J Wright; S Myhra

doi:10.1117/12.471941

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Interactions of poly(amino acids) in aqueous solution with charged model surfaces - Analysis by colloidal probe

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Interactions of poly(amino acids) in aqueous solution with charged model surfaces - Analysis by colloidal probe

Gregory S Watson, Jolanta A Blach, C Cahill, D V Nicolau, D K Pham, J Wright and S Myhra

Proceedings of SPIE - International Society for Optical Engineering, Vol.4937, pp.274-284

Biomedical Applications of Micro- and Nanoengineering, 2002 (Melbourne, Australia, 16-Dec-2002–18-Dec-2002)

SPIE: International Society for Optical Engineering

2002

DOI: https://doi.org/10.1117/12.471941

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Abstract

atomic force microscopy

DLVO model

double layer interactions

poly(amino acids)

colloids

organic polymers

silicon

solutions

surface properties

colloidal probes

amino acids

Biomolecules in a confined solution environment may be subject to electrostatic forces with a range up to 100 nm, while the van der Waals interaction will account for shorter-range forces. The response of two model poly(amino acids) - poly-L-lysine and poly-L-glutamic acid - has been investigated for a number of model surfaces at pH 6 - including silica/Si-oxide. The model amino acids were adsorbed, or covalently coupled, to colloidal probes consisting of a microsphere attached to a force-sensing lever. The methodology was based on sensing of an interaction between the probe and a flat surface through carrying out force versus distance analysis with an atomic force microscope. The results were analysed within the framework of the conventional DLVO theory. The outcomes illustrate both repulsive and attractive long-range interactions that will hinder, or promote, colloidal biospecies in solution from entering the region of short-range force-fields at the physical interface. Accordingly the results have implications for the efficacy of methods and devices that seek to exploit the properties of micro/nano-fluidic systems. Large 'snap-on' distances were observed for some systems and were ascribed to compression of the 'soft' functionalized layers. Those observations and measurements of adhesion provided insights into conformation of the adsorbed species and strength of attachment.

Details

Title: Interactions of poly(amino acids) in aqueous solution with charged model surfaces - Analysis by colloidal probe
Authors: Gregory S Watson (Author) - Griffith University
Jolanta A Blach (Author) - Griffith University
C Cahill (Author) - Griffith University
D V Nicolau (Author) - Griffith University
D K Pham (Author) - Griffith University
J Wright (Author) - Griffith University
S Myhra (Author) - Griffith University
Contributors: Dan V Nicolau (Editor)
Publication details: Proceedings of SPIE - International Society for Optical Engineering, Vol.4937, pp.274-284
Conference details: Biomedical Applications of Micro- and Nanoengineering, 2002 (Melbourne, Australia, 16-Dec-2002–18-Dec-2002)
Publisher: SPIE: International Society for Optical Engineering
Date published: 2002
DOI: 10.1117/12.471941
ISBN: 9780819447302
Organisation Unit: School of Science and Engineering - Legacy; University of the Sunshine Coast, Queensland; School of Science, Technology and Engineering
Language: English
Record Identifier: 99449499802621
Output Type: Conference paper

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