Thermodynamic Analysis of Proteins Adsorbed on Silica Particles: Electrostatic Effects

Larsericsdotter, Helén; Oscarsson, Sven; Buijs, Jos

doi:10.1006/jcis.2001.7485

Cited by 104 publications

(91 citation statements)

References 33 publications

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“…The fact that adsorption occurs means that the electrostatic repulsion has to be overcome. Hydrophobic interactions therefore contribute the most to the adsorption process, as was found for the adsorption of BLA on hydrophobic interfaces (15,26). However, minor contributions of electrostatic interactions cannot be excluded.…”

Section: Resultsmentioning

confidence: 86%

“…The intensity increase is related to a reduction in quenching that results from a different position of the tryptophan residues compared with their original position in the three-dimensional structure of native BLA. For native BLA it is suggested that energy transfer occurs from Trp 26 (27). It has also been observed that unfolding of BLA results in a red shift of the fluorescence emission maximum and an accompanied increase in fluorescence intensity (28) one or more Trp residues in the hydrophobic core of BLA.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Kinetic and Structural Characterization of Adsorption-induced Unfolding of Bovine α-Lactalbumin

Engel

Mierlo²,

Visser

2002

Journal of Biological Chemistry

101

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Conformational changes of bovine ␣-lactalbumin induced by adsorption on a hydrophobic interface are studied by fluorescence and circular dichroism spectroscopy. Adsorption of bovine ␣-lactalbumin on hydrophobic polystyrene nanospheres induces a non-native state of the protein, which is characterized by preserved secondary structure, lost tertiary structure, and release of calcium. This partially denatured state therefore resembles a molten globule state, which is an intermediate in the folding of bovine ␣-lactalbumin. Stopped-flow fluorescence spectroscopy reveals two kinetic phases during adsorption with rate constants k 1 ϳ 50 s ؊1 and k 2 ϳ 8 s ؊1 . The rate of partial unfolding is remarkably fast and even faster than unfolding induced by the addition of 5.4 M guanidinium hydrochloride to native ␣-lactalbumin. The large unfolding rates exclude the possibility that unfolding of bovine ␣-lactalbumin to the intermediate state occurs before adsorption takes place. Stoppedflow fluorescence anisotropy experiments show that adsorption of bovine ␣-lactalbumin on polystyrene nanospheres occurs within the dead time (15 ms) of the experiment. This shows that the kinetic processes as determined by stopped-flow fluorescence spectroscopy are not affected by diffusion or association processes but are solely caused by unfolding of bovine ␣-lactalbumin induced by adsorption on the polystyrene surface. A scheme is presented that incorporates the results obtained and describes the adsorption of bovine ␣-lactalbumin.Adsorption of proteins on solid/liquid interfaces is a generally occurring phenomenon both in nature and in man-made systems. It is well recognized that proteins undergo conformational changes upon adsorption on solid/liquid interfaces (1-3). Because unfolding of proteins can have a large effect on their function or properties, it is important to increase the knowledge about protein adsorption and about the resulting conformational changes. It is necessary to study not only the conformation of a protein in the adsorbed state but also the kinetics of the adsorption-induced conformational changes. This knowledge will help in controlling wanted or unwanted conformational changes of adsorbed proteins.In this work we focus on the kinetics of adsorption-induced conformational changes of bovine ␣-lactalbumin (BLA) 1 upon interaction with colloidal polystyrene nanospheres. Detailed information on adsorption-induced conformational changes and especially on the kinetics of adsorption-induced conformational changes is sparse. An important reason for this is the experimental difficulty of the presence of an adsorbent, which is usually a solid phase. A few routes have been designed to remove this difficulty. A macroscopic solid/water interface can be used in combination with a reflective technique like ellipsometry or total internal reflection fluorescence (4, 5). In other cases a microscopic system has been used that consists of small particles with diameters ranging from nanometers to micrometers in size (6, 7). The latter syst...

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Section: Resultsmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Kinetic and Structural Characterization of Adsorption-induced Unfolding of Bovine α-Lactalbumin

Engel

Mierlo²,

Visser

2002

Journal of Biological Chemistry

101

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“…Differential scanning calorimetry (DSC) was used to demonstrate the electrostatic nature of the bond of the adsorbed proteins on silica particles, and these measurements allowed the calculation of the thermodynamic binding parameters. [42] A theoretical model was developed to correlate the structure of metal core /protein shell NPs with the experimental data obtained from the light-scattering spectra. [37] The method of rapid expansion of a supercritical solution into a liquid solvent was applied for the preparation of BSA protein-conjugated Ag or Ag 2 S NPs.…”

Section: Functionalization Of Nanoparticles With Biomolecules Throughmentioning

confidence: 99%

Integrated Nanoparticle–Biomolecule Hybrid Systems: Synthesis, Properties, and Applications

2004

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Nanomaterials, such as metal or semiconductor nanoparticles and nanorods, exhibit similar dimensions to those of biomolecules, such as proteins (enzymes, antigens, antibodies) or DNA. The integration of nanoparticles, which exhibit unique electronic, photonic, and catalytic properties, with biomaterials, which display unique recognition, catalytic, and inhibition properties, yields novel hybrid nanobiomaterials of synergetic properties and functions. This review describes recent advances in the synthesis of biomolecule-nanoparticle/nanorod hybrid systems and the application of such assemblies in the generation of 2D and 3D ordered structures in solutions and on surfaces. Particular emphasis is directed to the use of biomolecule-nanoparticle (metallic or semiconductive) assemblies for bioanalytical applications and for the fabrication of bioelectronic devices.

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“…The electrostatic effect on the adsorption of proteins such as lysozyme, ribonuclease-A (RNase) and L-lectalbumin was investigated using differential scanning calorimetry (DSC) and adsorption isotherms [198]. The thermal denaturation and adsorption onto silica nanoparticles at three different concentrations: 10 M and 100 mM of sodium, and 100 mM of sodium added with 10 mM of calcium, were analyzed and the denaturation enthalpy (ΔH), the temperature at which the denaturation was half completed (T m ) and the temperature range of denaturation transition were calculated.…”

Section: Adsorption Of Biomolecules On Silica Surfacementioning

confidence: 99%

Adsorption of organic molecules on silica surface

Parida¹,

Dash²,

Patel³

et al. 2006

Advances in Colloid and Interface Science

604

360

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Thermodynamic Analysis of Proteins Adsorbed on Silica Particles: Electrostatic Effects

Cited by 104 publications

References 33 publications

Kinetic and Structural Characterization of Adsorption-induced Unfolding of Bovine α-Lactalbumin

Kinetic and Structural Characterization of Adsorption-induced Unfolding of Bovine α-Lactalbumin

Integrated Nanoparticle–Biomolecule Hybrid Systems: Synthesis, Properties, and Applications

Adsorption of organic molecules on silica surface

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