1
|
Haq EU, Zhang Y, O'Dowd N, Liu N, Leesment S, Becker C, Rossi EM, Sebastiani M, Tofail SAM, Silien C. Quantitative surface free energy with micro-colloid probe pairs. RSC Adv 2023; 13:2718-2726. [PMID: 36741155 PMCID: PMC9847652 DOI: 10.1039/d2ra05508b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 12/15/2022] [Indexed: 01/20/2023] Open
Abstract
Measurement of the surface free energy (SFE) of a material allows the prediction of its adhesion properties. Materials can have microscale or sub-microscale surface inhomogeneities, engineered or random, which affect the surface macroscopic behaviour. However, quantitative characterization of the SFE at such length scales remains challenging in view of the variety of instruments and techniques available, the poor knowledge of critical variables and parameters during measurements and the need for appropriate contact models to derive the SFE from the measurements. Failure to characterize adhesion correctly may result in defective components or lengthy process optimization costing billions to industry. Conversely, for planar and homogeneous surfaces, contact angle (CA) measurements are standardized and allow for calculating the SFE using for example the Owen-Wendt model, relying only on the properties of the probing liquids. As such, we assessed and report here a method to correlate quantitative measurements of force-distance curves made with an atomic force microscope (AFM) and with silica and polystyrene (PS) colloidal probe pairs, with quantitative CA measurements and CA-derived SFE values. We measured five surfaces (mica, highly oriented pyrolytic graphite, thermally grown silica on silicon, silicon, and silicon with a super-hydrophobic coating), ranging from hydrophilic to super-hydrophobic, and found an excellent classification of the AFM measurements when these are represented by a set of principal components (PCs), and when both silica and PS colloidal probes are considered together. A regression of the PCs onto the CA measurements allows recovery of the SFE at the length scale of the colloidal probes, which is here ca. 1 micron. We found that once the PC-regression model is built, test sets of only ten AFM force-distance curves are sufficient to predict the local SFE with the calibrated silica and PS colloidal probes.
Collapse
Affiliation(s)
- Ehtsham-Ul Haq
- Department of Physics and Bernal Institute, University of Limerick Limerick V94 T9PX Ireland
| | - Yongliang Zhang
- Department of Physics and Bernal Institute, University of Limerick Limerick V94 T9PX Ireland
| | - Noel O'Dowd
- School of Engineering and Bernal Institute, University of Limerick Limerick V94 T9PX Ireland
| | - Ning Liu
- Department of Physics and Bernal Institute, University of Limerick Limerick V94 T9PX Ireland
| | - Stanislav Leesment
- Spectrum Instruments Ltd. Stewart House, National Technological Park Limerick Ireland
| | - Claude Becker
- Funcoats SA Technoport 4B, Rue du Commerce Foetz Luxembourg
| | - Edoardo M Rossi
- Engineering Department, Roma Tre University Via della Vasca Navale 79 Rome 00146 Italy
| | - Marco Sebastiani
- Engineering Department, Roma Tre University Via della Vasca Navale 79 Rome 00146 Italy
| | - Syed A M Tofail
- Department of Physics and Bernal Institute, University of Limerick Limerick V94 T9PX Ireland
| | - Christophe Silien
- Department of Physics and Bernal Institute, University of Limerick Limerick V94 T9PX Ireland
| |
Collapse
|
2
|
de Castro ASB, de Paula HMC, Coelho YL, Hudson EA, Pires ACS, da Silva LHM. Kinetic and thermodynamic of lactoferrin - Ethoxylated-nonionic surfactants supramolecular complex formation. Int J Biol Macromol 2021; 187:325-331. [PMID: 34280448 DOI: 10.1016/j.ijbiomac.2021.07.087] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 06/28/2021] [Accepted: 07/13/2021] [Indexed: 11/19/2022]
Abstract
Understanding nonionic surfactant-protein interactions is fundamental from both technological and scientific points of view. However, there is a complete absence of kinetic data for such interactions. We employed surface plasmon resonance (SPR) to determine the kinetic and thermodynamic parameters of bovine lactoferrin-Brij58 interactions at various temperatures under physiological conditions (pH 7.4). The adsorption process was accelerated with increasing temperature, while the desorption rate decreased, resulting in a more thermodynamically stable complex. The kinetic energetic parameters obtained for the formation of the activated complex, [bLF-Brij58]‡, indicated that the potential energy barrier for [bLF-Brij58]‡ formation arises primarily from the reduction in system entropy. [bLF-Brij58]○ formation was entropically driven, indicating that hydrophobic interactions play a fundamental role in bLF interactions with Brij58.
Collapse
Affiliation(s)
- Alan Stampini Benhame de Castro
- Colloidal, macromolecular and Green Chemistry (QUIVECOM), Chemistry Department, Federal University of Viçosa, Av. PH Rolfs, s/n, Viçosa, MG 36570-900, Brazil
| | - Hauster Maximiler Campos de Paula
- Colloidal, macromolecular and Green Chemistry (QUIVECOM), Chemistry Department, Federal University of Viçosa, Av. PH Rolfs, s/n, Viçosa, MG 36570-900, Brazil
| | - Yara Luiza Coelho
- Colloidal, macromolecular and Green Chemistry (QUIVECOM), Chemistry Department, Federal University of Viçosa, Av. PH Rolfs, s/n, Viçosa, MG 36570-900, Brazil; Colloid Chemistry Group, Chemistry Institute, Federal University of Alfenas (UNIFAL-MG), Rua Gabriel Monteiro da Silva, 700, 37130-000 Alfenas, MG, Brazil
| | - Eliara Acipreste Hudson
- Applied Molecular Thermodynamic (THERMA), Food Technology Department, Federal University of Viçosa, Av. PH Rolfs, s/n, Viçosa, MG 36570-900, Brazil
| | - Ana Clarissa S Pires
- Applied Molecular Thermodynamic (THERMA), Food Technology Department, Federal University of Viçosa, Av. PH Rolfs, s/n, Viçosa, MG 36570-900, Brazil
| | - Luis Henrique M da Silva
- Colloidal, macromolecular and Green Chemistry (QUIVECOM), Chemistry Department, Federal University of Viçosa, Av. PH Rolfs, s/n, Viçosa, MG 36570-900, Brazil.
| |
Collapse
|
3
|
Obeid S, Guyomarc'h F. Atomic force microscopy of food assembly: Structural and mechanical insights at the nanoscale and potential opportunities from other fields. FOOD BIOSCI 2020. [DOI: 10.1016/j.fbio.2020.100654] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
4
|
Singh G, Bremmell K, Griesser HJ, Kingshott P. Colloid-probe AFM studies of the surface functionality and adsorbed proteins on binary colloidal crystal layers. RSC Adv 2017. [DOI: 10.1039/c6ra28491d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We demonstrate the applicability of colloid-probe AFM to detect different surface chemistries on binary colloidal crystal layers of different chemical and protein patterns.
Collapse
Affiliation(s)
- Gurvinder Singh
- Interdisciplinary Nanoscience Centre
- Faculty of Science
- Aarhus University
- Denmark
- Department of Materials Science and Engineering
| | - Kristen Bremmell
- School of Pharmacy and Medical Sciences
- University of South Australia
- Adelaide 5000
- Australia
| | - Hans J. Griesser
- Future Industries Institute
- University of South Australia
- Mawson Lakes
- Australia
| | - Peter Kingshott
- Interdisciplinary Nanoscience Centre
- Faculty of Science
- Aarhus University
- Denmark
- Department of Chemistry and Biotechnology
| |
Collapse
|
5
|
Wang Z, He C, Gong X, Wang J, Ngai T. Measuring the Surface-Surface Interactions Induced by Serum Proteins in a Physiological Environment. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:12129-12136. [PMID: 27794620 DOI: 10.1021/acs.langmuir.6b03420] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this work, we applied total internal reflection microscopy (TIRM) to directly measure the interactions between three different kinds of macroscopic surfaces: namely bare polystyrene (PS) particle and bare silica surface (bare-PS/bare-silica), PS particle and silica surfaces both coated with bovine serum albumin (BSA) (BSA-PS/BSA-silica), and PS particle and silica surfaces both modified with polyethylene glycol (PEG) (PEG-PS/PEG-silica) polymers, in phosphate buffer solution (PBS) and fetal bovine serum (FBS). Our results showed that in PBS, all the bare-PS, BSA-PS, and PEG-PS particles were irreversibly deposited onto the bare silica surface or surfaces coated either with BSA or PEG. However, in FBS, the interaction potentials between the particle and surface exhibited both free-diffusing particle and stuck particle profiles. Dynamic light scattering (DLS) and elliposmeter measurements indicated that there was a layer of serum proteins adsorbed on the PS particle and silica surface. TIRM measurement revealed that such adsorbed serum proteins can mediate the surface-surface interactions by providing additional stabilization under certain conditions, but also promoting bridging effect between the two surfaces. The measured potential profile of the stuck particle in FBS thus was much wider than in PBS. These quantitative measurements provide insights that serum proteins adsorbed onto surfaces can regulate surface-surface interactions, thus leading to unique moving behavior and stability of colloidal particles in the serum environment.
Collapse
Affiliation(s)
- Zhaohui Wang
- Department of Chemistry, The Chinese University of Hong Kong , Shatin, N.T., Hong Kong SAR, The People's Republic of China
| | - Chuanxin He
- College of Chemistry and Environmental Engineering, Shenzhen University , Shenzhen, China 518060
| | - Xiangjun Gong
- School of Materials Science and Engineering, South China University of Technology , Guangzhou, China 510640
| | - Jianqi Wang
- Department of Chemistry, The Chinese University of Hong Kong , Shatin, N.T., Hong Kong SAR, The People's Republic of China
| | - To Ngai
- Department of Chemistry, The Chinese University of Hong Kong , Shatin, N.T., Hong Kong SAR, The People's Republic of China
| |
Collapse
|
6
|
Structure formation in pH-sensitive hydrogels composed of sodium caseinate and N,O-carboxymethyl chitosan. Int J Biol Macromol 2016; 89:353-9. [DOI: 10.1016/j.ijbiomac.2016.04.081] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 04/25/2016] [Accepted: 04/27/2016] [Indexed: 11/22/2022]
|
7
|
Moore TL, Rodriguez-Lorenzo L, Hirsch V, Balog S, Urban D, Jud C, Rothen-Rutishauser B, Lattuada M, Petri-Fink A. Nanoparticle colloidal stability in cell culture media and impact on cellular interactions. Chem Soc Rev 2015; 44:6287-6305. [PMID: 26056687 DOI: 10.1039/c4cs00487f] [Citation(s) in RCA: 641] [Impact Index Per Article: 71.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nanomaterials are finding increasing use for biomedical applications such as imaging, diagnostics, and drug delivery. While it is well understood that nanoparticle (NP) physico-chemical properties can dictate biological responses and interactions, it has been difficult to outline a unifying framework to directly link NP properties to expected in vitro and in vivo outcomes. When introduced to complex biological media containing electrolytes, proteins, lipids, etc., nanoparticles (NPs) are subjected to a range of forces which determine their behavior in this environment. One aspect of NP behavior in biological systems that is often understated or overlooked is aggregation. NP aggregation will significantly alter in vitro behavior (dosimetry, NP uptake, cytotoxicity), as well as in vivo fate (pharmacokinetics, toxicity, biodistribution). Thus, understanding the factors driving NP colloidal stability and aggregation is paramount. Furthermore, studying biological interactions with NPs at the nanoscale level requires an interdisciplinary effort with a robust understanding of multiple characterization techniques. This review examines the factors that determine NP colloidal stability, the various efforts to stabilize NP in biological media, the methods to characterize NP colloidal stability in situ, and provides a discussion regarding NP interactions with cells.
Collapse
Affiliation(s)
- Thomas L Moore
- Adolphe Merkle Institute, University of Fribourg, 1700 Fribourg, Switzerland.
| | | | - Vera Hirsch
- Adolphe Merkle Institute, University of Fribourg, 1700 Fribourg, Switzerland.
| | - Sandor Balog
- Adolphe Merkle Institute, University of Fribourg, 1700 Fribourg, Switzerland.
| | - Dominic Urban
- Adolphe Merkle Institute, University of Fribourg, 1700 Fribourg, Switzerland.
| | - Corinne Jud
- Adolphe Merkle Institute, University of Fribourg, 1700 Fribourg, Switzerland.
| | | | - Marco Lattuada
- Adolphe Merkle Institute, University of Fribourg, 1700 Fribourg, Switzerland.
| | - Alke Petri-Fink
- Adolphe Merkle Institute, University of Fribourg, 1700 Fribourg, Switzerland.
- Chemistry Department, University of Fribourg, 1700 Fribourg, Switzerland.
| |
Collapse
|
8
|
Singh G, Bremmell KE, Griesser HJ, Kingshott P. Colloid-probe AFM studies of the interaction forces of proteins adsorbed on colloidal crystals. SOFT MATTER 2015; 11:3188-3197. [PMID: 25758979 DOI: 10.1039/c4sm02669a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In recent years, colloid-probe AFM has been used to measure the direct interaction forces between colloidal particles of different size or surface functionality in aqueous media, as one can study different forces in symmerical systems (i.e., sphere-sphere geometry). The present study investigates the interaction between protein coatings on colloid probes and hydrophilic surfaces decorated with hexagonally close packed single particle layers that are either uncoated or coated with proteins. Controlled solvent evaporation from aqueous suspensions of colloidal particles (coated with or without lysozyme and albumin) produces single layers of close-packed colloidal crystals over large areas on a solid support. The measurements have been carried out in an aqueous medium at different salt concentrations and pH values. The results show changes in the interaction forces as the surface charge of the unmodified or modified particles, and ionic strength or pH of the solution is altered. At high ionic strength or pH, electrostatic interactions are screened, and a strong repulsive force at short separation below 5 nm dominates, suggesting structural changes in the absorbed protein layer on the particles. We also study the force of adhesion, which decreases with an increment in the salt concentration, and the interaction between two different proteins indicating a repulsive interaction on approach and adhesion on retraction.
Collapse
Affiliation(s)
- Gurvinder Singh
- Interdisciplinary Nanoscience Centre, Faculty of Science, Aarhus University, Ny Munkegade, Aarhus C 8000, Denmark
| | | | | | | |
Collapse
|
9
|
Chow LM, Subbaraman LN, Sheardown H, Jones L. Kinetics of in Vitro Lactoferrin Deposition on Silicone Hydrogel and FDA Group II and Group IV Hydrogel Contact Lens Materials. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 20:71-82. [PMID: 19105901 DOI: 10.1163/156856208x393509] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Lisa M. Chow
- a Centre for Contact Lens Research, School of Optometry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| | - Lakshman N. Subbaraman
- b Centre for Contact Lens Research, School of Optometry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| | - Heather Sheardown
- c Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L8
| | - Lyndon Jones
- d Centre for Contact Lens Research, School of Optometry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| |
Collapse
|
10
|
Valle-Delgado J, Molina-Bolívar J, Galisteo-González F, Gálvez-Ruiz M. Evidence of hydration forces between proteins. Curr Opin Colloid Interface Sci 2011. [DOI: 10.1016/j.cocis.2011.04.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
11
|
Chaudhari K, Xavier PL, Pradeep T. Understanding the evolution of luminescent gold quantum clusters in protein templates. ACS NANO 2011; 5:8816-27. [PMID: 22010989 DOI: 10.1021/nn202901a] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We show that the time-dependent biomineralization of Au(3+) by native lactoferrin (NLf) and bovine serum albumin (BSA) resulting in near-infrared (NIR) luminescent gold quantum clusters (QCs) occurs through a protein-bound Au(1+) intermediate and subsequent emergence of free protein. The evolution was probed by diverse tools, principally, using matrix-assisted laser desorption ionization mass spectrometry (MALDI MS), X-ray photoelectron spectroscopy (XPS), and photoluminescence spectroscopy (PL). The importance of alkaline pH in the formation of clusters was probed. At neutral pH, a Au(1+)-protein complex was formed (starting from Au(3+)) with the binding of 13-14 gold atoms per protein. When the pH was increased above 12, these bound gold ions were further reduced to Au(0) and nucleation and growth of cluster commenced, which was corroborated by the beginning of emission; at this point, the number of gold atoms per protein was ~25, suggesting the formation of Au(25). During the cluster evolution, at certain time intervals, for specific molar ratios of gold and protein, occurrence of free protein was noticed in the mass spectra, suggesting a mixture of products and gold ion redistribution. By providing gold ions at specific time of the reaction, monodispersed clusters with enhanced luminescence could be obtained, and the available quantity of free protein could be utilized efficiently. Monodispersed clusters would be useful in obtaining single crystals of protein-protected noble metal quantum clusters where homogeneity of the system is of primary concern.
Collapse
Affiliation(s)
- Kamalesh Chaudhari
- Department of Biotechnology, Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India
| | | | | |
Collapse
|
12
|
Xavier PL, Chaudhari K, Verma PK, Pal SK, Pradeep T. Luminescent quantum clusters of gold in transferrin family protein, lactoferrin exhibiting FRET. NANOSCALE 2010; 2:2769-76. [PMID: 20882247 DOI: 10.1039/c0nr00377h] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We report the synthesis of highly luminescent, water soluble quantum clusters (QCs) of gold, which are stabilized by an iron binding transferrin family protein, lactoferrin (Lf). The synthesized AuQC@Lf clusters were characterized using UV-Visible spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), photoluminescence (PL), matrix assisted laser desorption ionization mass spectrometry (MALDI-MS), FTIR spectroscopy and circular dichroism (CD) spectroscopy along with picosecond-resolved lifetime measurements. Detailed investigations with FTIR and CD spectroscopy have revealed changes in the secondary structure of the protein in the cluster. We have also studied Förster resonance energy transfer (FRET) occurring between the protein and the cluster. The ability of the clusters to sense cupric ions selectively at ppm concentrations was tested. The stability of clusters in widely varying pH conditions and their continued luminescence make it feasible for them to be used for intracellular imaging and molecular delivery, particularly in view of Lf protection.
Collapse
Affiliation(s)
- Paulrajpillai Lourdu Xavier
- DST Unit on Nanoscience (DST UNS), Department of Chemistry and Sophisticated Analytical Instrument Facility, Indian Institute of Technology Madras, Chennai, 600 036, India
| | | | | | | | | |
Collapse
|
13
|
Persson BA, Lund M, Forsman J, Chatterton DE, Åkesson T. Molecular evidence of stereo-specific lactoferrin dimers in solution. Biophys Chem 2010; 151:187-9. [DOI: 10.1016/j.bpc.2010.06.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 06/15/2010] [Accepted: 06/18/2010] [Indexed: 10/19/2022]
|
14
|
Measurement of interaction forces between fibrinogen coated probes and mica surface with the atomic force microscope: The pH and ionic strength effect. Biointerphases 2010; 3:1-8. [PMID: 20408656 DOI: 10.1116/1.2840052] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The study of protein-surface interactions is of great significance in the design of biomaterials and the evaluation of molecular processes in tissue engineering. The authors have used atomic force microscopy (AFM) to directly measure the force of attraction/adhesion of fibrinogen coated tips to mica surfaces and reveal the effect of the surrounding solution pH and ionic strength on this interaction. Silica colloid spheres were attached to the AFM cantilevers and, after plasma deposition of poly(acrylic acid), fibrinogen molecules were covalently bound on them with the help of the cross-linker 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) in the presence of N-hydroxysulfosuccinimide (sulfo-NHS). The measurements suggest that fibrinogen adsorption is controlled by the screening of electrostatic repulsion as the salt concentration increases from 15 to 150 mM, whereas at higher ionic strength (500 mM) the hydration forces and the compact molecular conformation become crucial, restricting adsorption. The protein attraction to the surface increases at the isoelectric point of fibrinogen (pH 5.8), compared with the physiological pH. At pH 3.5, apart from fibrinogen attraction to the surface, evidence of fibrinogen conformational changes is observed, as the pH and the ionic strength are set back and forth, and these changes may account for fibrinogen aggregation in the protein solution at this pH.
Collapse
|
15
|
Popplewell JF, Swann MJ, Ahmed Y, Turnbull JE, Fernig DG. Fabrication of carbohydrate surfaces by using nonderivatised oligosaccharides, and their application to measuring the assembly of sugar-protein complexes. Chembiochem 2009; 10:1218-26. [PMID: 19360804 DOI: 10.1002/cbic.200800696] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This way up. Dual polarisation interferometry was used to design and characterise a surface on which the orientation and density of immobilised carbohydrates was suitable for studying their interactions with proteins. Lactoferrin was shown to adopt two orientations: "end-on" or "side-on", while for FGF-2 a single monolayer of protein was observed. The new surface can be used to elucidate the binding of proteins to carbohydrates and the geometry of the complexes, a frequently controversial area. Surface-based tools, such as microarrays and optical biosensors, are being increasingly applied to the analysis of carbohydrate-protein interactions. A key to these developments is the presentation of the carbohydrate to the protein target. Dual polarisation interferometry (DPI) is a surface-based technique that permits the real-time measurement of the changes in thickness, refractive index and mass of adsorbates 100 nm thick or less on the surface of a functionalised waveguide. DPI has been used to design and characterise a surface on which the orientation and density of the immobilised carbohydrates is suitable for studying their interactions with proteins and where nonspecific binding is reduced to less than 5 % of total binding. A thiol-functionalised surface was derivatised with a heterobifunctional crosslinker to yield a hydrazide surface. This was treated with oligosaccharides, derived from keratan sulfate (KS) chondroitin sulfate (CS) and heparin, that possess a reducing end. To block the unreacted hydrazide groups, the surface was treated with an aldehyde-functionalised PEG. The heparin DP-10 surfaces were then used to determine the performance of the immobilised DP-10 with respect to binding of two well-characterised proteins, lactoferrin (Lf) and fibroblast growth factor-2. The results show that Lf could adopt two different orientations, at high protein loadings the protein layer thickness corresponded to an "end-on" orientation of Lf, whilst rinsing with buffer saw the Lf molecules adopt a "side-on" configuration. In the case of FGF-2, a single monolayer of protein bound to DP-10 was observed. These results demonstrate that the new surface can be used to resolve key questions relating to the binding of proteins to carbohydrates, including, when used in DPI, the resolution of the geometry of complexes, an area that is frequently controversial.
Collapse
|
16
|
Liang Y, Hilal N, Langston P, Starov V. Interaction forces between colloidal particles in liquid: theory and experiment. Adv Colloid Interface Sci 2007; 134-135:151-66. [PMID: 17499205 DOI: 10.1016/j.cis.2007.04.003] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Revised: 04/02/2007] [Accepted: 04/08/2007] [Indexed: 11/22/2022]
Abstract
The interaction forces acting between colloidal particles in suspensions play an important part in determining the properties of a variety of materials, the behaviour of a range of industrial and environmental processes. Below we briefly review the theories of the colloidal forces between particles and surfaces including London-van der Waals forces, electrical double layer forces, solvation forces, hydrophobic forces and steric forces. In the framework of Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, theoretical predictions of total interparticle interaction forces are discussed. A survey of direct measurements of the interaction forces between colloidal particles as a function of the surface separation is presented. Most of the measurements have been carried out mainly using the atomic force microscopy (AFM) as well as the surface force apparatus (SFA) in the liquid phase. With the highly sophisticated and versatile techniques that are employed by far, the existing interaction theories between surfaces have been validated and advanced. In addition, the direct force measurements by AFM have also been useful in the explaining or understanding of more complex phenomena and in engineering the products and processes occurring in many industrial applications.
Collapse
Affiliation(s)
- Yuncheng Liang
- School of Chemical, Environmental and Mining Engineering, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | | | | | | |
Collapse
|
17
|
Ye A, Singh H. Formation of Multilayers at the Interface of Oil-in-Water Emulsion via Interactions between Lactoferrin and β-Lactoglobulin. FOOD BIOPHYS 2007. [DOI: 10.1007/s11483-007-9029-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
18
|
Guryca V, Hobzová R, Prádný M, Sirc J, Michálek J. Surface morphology of contact lenses probed with microscopy techniques. Cont Lens Anterior Eye 2007; 30:215-22. [PMID: 17507281 DOI: 10.1016/j.clae.2007.02.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Revised: 02/21/2007] [Accepted: 02/24/2007] [Indexed: 11/24/2022]
Abstract
The present study is bringing a comparison of surface morphology for various types of contact lenses. A novel method--scanning electron microscopy under aqueous conditions (cryo-SEM)--was tested for visualization of lenses at magnifications up to 2000x. For imaging lens surface on nanometre scale, we employed atomic force microscopy (AFM) in aqueous media. Various materials of lenses, based on silicone hydrogels or conventional hydrogels, were investigated. Total, 10 types of contact lenses from five manufacturers were selected and probed. We found that different methods of lens manufacture (lathe-cutting, cast-moulding, and spin casting) led to different values of surface roughness. In the swollen state, roughness values of lens surfaces lie between 4 and 140 nm. Lenses manufactured by lathe-cutting exhibit notable higher values, so that they could be easily distinguished from others. In cast-moulded lenses, the surface roughness decreased with increasing water content. Moreover, additional treatments of lenses introduced unique structural motifs onto surface. For instance, porous structure was found on lens surface finalized with plasma oxidation.
Collapse
Affiliation(s)
- Vilém Guryca
- Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic
| | | | | | | | | |
Collapse
|
19
|
Tsapikouni TS, Missirlis YF. pH and ionic strength effect on single fibrinogen molecule adsorption on mica studied with AFM. Colloids Surf B Biointerfaces 2007; 57:89-96. [PMID: 17337166 DOI: 10.1016/j.colsurfb.2007.01.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Revised: 01/18/2007] [Accepted: 01/18/2007] [Indexed: 10/23/2022]
Abstract
Although several investigations have been reported on the effect of pH or ionic strength on protein adsorption, most of them have been carried out with protein monolayers and not with single molecules. We have used atomic force microscopy to image, in phosphate buffer, single fibrinogen molecules adsorbed on mica and compare the surface coverage at variable pH (7.4, 5.8, 3.5) or ionic strength (15, 150, 500 mM) conditions. The images obtained and the statistical analysis of the surface coverage indicate adsorption enhancement at the IEP of fibrinogen (pH 5.8) and minimum adsorption at pH 3.5. On the other hand, more protein was adsorbed when the salt concentration of the buffer at pH 7.4 was increased from 15 to 150 mM. However, further increase of salt concentration up to 500 mM resulted in decreased adsorption. To confirm the aforementioned results an approaching bare Si(3)N(4) tip was used as an electrostatic analogue to a protein molecule and interaction force curves between it and the substrate were recorded. The results were in consistence with the double layer theory which justifies the screening of electrostatic repulsion as the salt concentration increases.
Collapse
Affiliation(s)
- Theodora S Tsapikouni
- Laboratory of Biomechanics and Biomedical Engineering, Mechanical Engineering and Aeronautics Department, University of Patras, Patras 26504, Greece
| | | |
Collapse
|
20
|
Legay G, Finot E, Meunier-Prest R, Cherkaoui-Malki M, Latruffe N, Dereux A. DNA nanofilm thickness measurement on microarray in air and in liquid using an atomic force microscope. Biosens Bioelectron 2006; 21:627-36. [PMID: 16202876 DOI: 10.1016/j.bios.2004.12.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2004] [Revised: 12/01/2004] [Accepted: 12/23/2004] [Indexed: 11/29/2022]
Abstract
The measurement of the thickness of DNA films on microarray as a function of the medium (liquid, air) is gaining importance for understanding the signal response of biosensors. Thiol group has been used to attach DNA strands to gold micropads deposited on silicon surface. Atomic force microscopy (AFM) was employed in its height mode to measure the change in the pad thickness and in its force mode to measure the indentation depth of the nanofilm. A good coherence between the height and force modes is observed for the film thickness in air. The adhesion force was found to be an alternative way to measure the surface coverage of the biolayer at nanoscopic scale. However the force analysis (compression, steric and electrostatic) provides baseline information necessary to interpret the AFM height image in liquid. Analysis of the film thickness distribution shows that the height of the DNA strands depends on both the DNA strand length (15-35 base pairs) and the environment (air, liquid). In air, longer strands lay down onto gold surface whereas the charge reversal of gold in liquid causes a repulsion of longer strands, which stand up.
Collapse
Affiliation(s)
- Guillaume Legay
- Laboratoire de Physique, UMR CNRS 5027, Université de Bourgogne, BP 47870, 9 Rue A. Savary, 21078 Dijon Cedex, France
| | | | | | | | | | | |
Collapse
|
21
|
Bremmell KE, Kingshott P, Ademovic Z, Winther-Jensen B, Griesser HJ. Colloid probe AFM investigation of interactions between fibrinogen and PEG-like plasma polymer surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:313-8. [PMID: 16378437 DOI: 10.1021/la052143a] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Interaction forces between surfaces designed to be protein resistant and fibrinogen (Fg) were investigated in phosphate-buffered saline with colloid probe atomic force microscopy. The surfaces of the silica probes were coated with a layer of fibrinogen molecules by adsorption from the buffer. The technique of low-power, pulsed AC plasma polymerization was used to make poly(ethylene glycol) (PEG)-like coatings on poly(ethylene teraphthalate) by using diethylene glycol vinyl ether as the monomer gas. The degree of PEG-like nature of the films was controlled by use of a different effective plasma power in the chamber for each coating, ranging from 0.6 to 3.6 W. This produced a series of thin films with a different number of ether carbons, as assessed by X-ray photoelectron spectroscopy. The interaction force measurements are discussed in relation to trends observed in the reduction of fibrinogen adsorption, as determined quantitatively by (125)I radio-labeling. The plasma polymer coatings with the greatest protein-repelling properties were the most PEG-like in nature and showed the strongest repulsion in interaction force measurements with the fibrinogen-coated probe. Once forced into contact, all the surfaces showed increased adhesion with the protein layer on the probe, and the strength and extension length of adhesion was dependent on both the applied load and the plasma polymer surface chemistry. When the medium was changed from buffer to water, the adhesion after contact was eliminated and only appeared at much higher loads. This indicates that the structure of the fibrinogen molecules on the probe is changed from an extended conformation in buffer to a flat conformation in water, with the former state allowing for stronger interaction with the polymer chains on the surface. These experiments underline the utility of aqueous surface force measurements toward understanding protein-surface interactions, and developing nonfouling surfaces that confer a steric barrier against protein adsorption.
Collapse
Affiliation(s)
- Kristen E Bremmell
- Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095, Australia.
| | | | | | | | | |
Collapse
|
22
|
Valle-Delgado JJ, Molina-Bolívar JA, Galisteo-González F, Gálvez-Ruiz MJ, Feiler A, Rutland MW. Existence of hydration forces in the interaction between apoferritin molecules adsorbed on silica surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:9544-54. [PMID: 16207034 DOI: 10.1021/la050825s] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The atomic force microscope, together with the colloid probe technique, has become a very useful instrument to measure interaction forces between two surfaces. Its potential has been exploited in this work to study the interaction between protein (apoferritin) layers adsorbed on silica surfaces and to analyze the effect of the medium conditions (pH, salt concentration, salt type) on such interactions. It has been observed that the interaction at low salt concentrations is dominated by electrical double layer (at large distances) and steric forces (at short distances), the latter being due to compression of the protein layers. The DLVO theory fits these experimental data quite well. However, a non-DLVO repulsive interaction, prior to contact of the protein layers, is observed at high salt concentration above the isoelectric point of the protein. This behavior could be explained if the presence of hydration forces in the system is assumed. The inclusion of a hydration term in the DLVO theory (extended DLVO theory) gives rise to a better agreement between the theoretical fits and the experimental results. These results seem to suggest that the hydration forces play a very important role in the stability of the proteins in the physiological media.
Collapse
Affiliation(s)
- J J Valle-Delgado
- Biocolloid and Fluid Physics Group, Department of Applied Physics, Science Faculty, University of Granada, 18071 Granada, Spain
| | | | | | | | | | | |
Collapse
|
23
|
He Y, Li HW, Yeung ES. Motion of Single DNA Molecules at a Liquid−Solid Interface As Revealed by Variable-Angle Evanescent-Field Microscopy. J Phys Chem B 2005; 109:8820-32. [PMID: 16852048 DOI: 10.1021/jp0447284] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A variable-angle total-internal-reflection fluorescence microscope (VATIRFM) capable of providing a large range of incident angles was constructed for imaging single DNA molecule dynamics at a solid/liquid interface. An algorithm using a public-domain image-processing program, ImageJ, was developed for single-molecule counting. The experimental counts at various incident angles with different evanescent-field layer (EFL) thicknesses are affected by molecular diffusion. The dynamics of molecules near the surface and the observed counts in the VATIRFM are elucidated using a limited one-dimensional random-walk diffusion model. The simulation fits well with the experimental counting results. Further analysis using the simulation reveals the details of single-molecule motion. One implication is that the measured intensities cannot be used directly to determine the distances of molecules from the surface, though the majority of fluorescence does come from the EFL. Another implication is that rather than providing molecular concentrations within EFL the experimental counting results depict the distance-dependent dynamics of molecules near the surface. Thus, the VATIRFM could be a powerful technique to study the surface repulsion/attraction of molecules within a few hundred nanometers of the surface. Further studies show that molecules at low ionic strengths experience electrostatic repulsion at distances much further away from the surface than the calculated thickness of the electrical double layer.
Collapse
Affiliation(s)
- Yan He
- Ames Laboratory, U. S. Department of Energy, Ames, Iowa 50011-3111, USA
| | | | | |
Collapse
|
24
|
Zhang H, Bremmell KE, Smart RSC. Direct measurement of interactions between adsorbed vitronectin layers: The influence of ionic strength and pH. J Biomed Mater Res A 2005; 74:59-68. [PMID: 15909285 DOI: 10.1002/jbm.a.30364] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Vitronectin (Vn) is an adhesive protein in the plasma serum and plays an important role in cell attachment, spreading, and proliferation. The interactions between protein bovine vitronectin layers adsorbed onto a silica probe and a mica surface have been investigated with the use of atomic force microscopy (AFM). Adsorption of vitronectin was confirmed by XPS surface analysis. The force-separation curves and pull-off forces were measured as a function of ionic strength and solution pH. The pull-off force (adhesion force) decreased as the salt concentration increased, which suggests that some binding domains of this protein may associate with the ionic species and reduce its binding ability. Discrete jumps, or discontinuities, in the separation force curve were observed to extend to a maximum of 300 nm, evidence that the protein molecules bridge between the surfaces. As a function of pH, the adhesion force on separation of the protein-coated surfaces showed a maximum at pH 5 (i.e.p. of vitronectin), decreasing in magnitude at lower and higher pH values. At pH 5, the approaching curves illustrated a jump-in force; whereas for pH values away from 5, the approaching force curves were repulsive. Correlation of the interaction forces with Vn conformational changes in different pH environments, directly visualized with the use of AFM imaging, was developed. In its i.e.p. region, the Vn molecular conformation appeared to be dense and compact. Significantly, at wounds/injured sites the pH is low (approximately 5) which this study discovered to facilitate adsorption and formation of vitronectin aggregates, known to trigger their subsequent biological functions.
Collapse
Affiliation(s)
- Hailong Zhang
- Ian Wark Research Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | | | | |
Collapse
|
25
|
Valle-Delgado JJ, Molina-Bolívar JA, Galisteo-González F, Gálvez-Ruiz MJ, Feiler A, Rutland M. Interactions between bovine serum albumin layers adsorbed on different substrates measured with an atomic force microscope. Phys Chem Chem Phys 2004. [DOI: 10.1039/b314060c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|