Analysis of the specificity and thermodynamics of the interaction between low affinity antibodies and carbohydrate antigens using fluorescence spectroscopy

Engström, Henrik A.; Andersson, Per Ola; Ohlson, Sten

doi:10.1016/j.jim.2004.12.010

Cited by 14 publications

(9 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Successful decoupling the impact of each factor on either the biomolecule penetration and/or dynamics may provide clues for efficient control of hydrogel functionality in numerous applications. Potentially, the gained fundamental understanding can aid the efficient design of separation membranes and novel sensors − or chromatographic setups − where binders of variable affinity strength − toward the matrix can be encountered.…”

Section: Introductionmentioning

confidence: 99%

Diffusion and Permeation of Labeled IgG in Grafted Hydrogels

et al. 2017

View full text Add to dashboard Cite

The permeation and translational diffusion of antibodies through the porous matrix of hydrogel materials is of fundamental relevance for many biological systems in living nature, but equally important in medical and technological applications, such as implanted drug release systems and biosensors. In this respect the diffusion of fluorophore-labeled protein immunoglobulin G (IgG) in micrometer thick, grafted hydrogel layers based on thermoresponsive poly(N-isopropylacrylamide) (pNiPAAm) is studied here by fluorescence correlation spectroscopy (FCS). The pore size of the gel gradually changes with its swelling state, which is controlled by the cross-link density of the network, temperature, and pH value of the surrounding medium. Notably, IgG permeation in these hydrogel layers exhibits a much more complex dependence on these factors. This rich variability of IgG permeation is attributed to the varying balance of protein interactions with the polymer network through electrostatics, controlled pH-dependent protein ionization, excluded volume repulsion, and hydrophobic attraction. A combined analysis of the fluorescence intensity profiles and the dynamics monitored by FCS allows us to quantify the thermodynamically controlled partitioning of IgG as well as the slowdown of its diffusion. Contrary to the complex behavior of the permeation, the diffusion slowdown seems to be a universal function of polymer volume fraction, which is rather robust with respect to temperature or pH changes. The presented findings suggest a model approach to explore the synergy between crowding and thermodynamics with respect to the controlled protein transport in pNiPAAm-based hydrogels.

show abstract

Section: Introductionmentioning

confidence: 99%

Diffusion and Permeation of Labeled IgG in Grafted Hydrogels

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Direct measurement of native fluorescence by proteins is also being pursued 14–18. Proteins exhibit intrinsic absorption maxima in the ultraviolet (UV) around 280 nm 19.…”

mentioning

confidence: 99%

Aluminum Nanoparticles as Substrates for Metal-Enhanced Fluorescence in the Ultraviolet for the Label-Free Detection of Biomolecules

et al. 2009

View full text Add to dashboard Cite

We use finite-difference time-domain calculations to show that aluminum nanoparticles are efficient substrates for metal-enhanced fluorescence (MEF) in the ultraviolet (UV) for the label-free detection of biomolecules. The radiated power enhancement of the fluorophores in proximity to aluminum nanoparticles is strongly dependent on the nanoparticle size, fluorophore-nanoparticle spacing, and fluorophore orientation. Additionally, the enhancement is dramatically increased when the fluorophore is between two aluminum nanoparticles of a dimer. Finally, we present experimental evidence that functionalized forms of amino acids tryptophan and tyrosine exhibit MEF when spincoated onto aluminum nanostructures.Fluorescence is widely used in biology and medicine. However, low radiative emission rates limit the use of the intrinsic fluorescence of biomolecules, resulting in the need for external chemical labeling. The use of external labels requires chemical modification and additional steps which can perturb the functionality of ligand-receptor interactions. In many cases, selective fluorescence labeling of a small number of molecules in a tiny volume like a single cell is cumbersome, adding expense and complexity to the analysis. [1][2][3][4][5] Because of the problems noted above, there is interest in label-free detection methods [6][7][8] including surface plasmon resonance 9,10 and Raman scattering. [11][12][13] Direct measurement of native fluorescence by proteins is also being pursued. [14][15][16][17][18] Proteins exhibit intrinsic absorption maxima in the ultraviolet (UV) around 280 nm. 19 We 20-23 and others [24][25][26] have been investigating metallic nanostructures for improved fluorescence detection. Metallic structures can substantially modify spontaneous emission rates and the directionality of the emission, leading to metal-enhanced fluorescence (MEF). In the case of a flat metal film on a glass substrate, emission from a fluorophore near the film can excite surface plasmon polaritons on the film, which radiate back into the glass in a highly directional manner, a process termed surface plasmon-coupled emission (SPCE).* To whom correspondence should be addressed. E-mail: lakowicz@cfs.umbi.umd.edu. † University of Maryland School of Medicine. ‡ Argonne National Laboratory. § Lumerical Solutions Inc. SUPPORTING INFORMATION AVAILABLEFurther details are given as noted in the text. This material is available free of charge via the Internet at http://pubs.acs.org. At present MEF and SPCE are obtained with mostly silver structures, 20,22,23,[27][28][29] with occasional use of gold, 30,31 and with relatively little attention being given to other metals such as aluminum. However, aluminum has low absorption at wavelengths ≤400 nm, and a recent article demonstrated that aluminum nanodisks have distinct plasmon resonances that extend into the UV. 32 Aluminum nanostructures have also been used for surface enhanced Raman spectroscopy (SERS). 33 These facts suggest that aluminum can potentially be used as a subs...

show abstract

“…Antibodies fragments (monoand bivalent Fab fragments), as well as mini-antibodies (fragments of the hypervariable sites) usually exhibit a lower affinity to antigens (Engström et al, 2005). The scheme of immunoaffinity isolation of surface antigen of hepatitis B virus was developed.…”

Section: Selection Of Low-affinity Antibodies Applicable For Antigen mentioning

confidence: 99%