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PubMedDate not supplied

Antigen-antibody binding kinetics for biosensor applications. A dual-fractal analysis.

The diffusion-limited binding kinetics of antigen (or antibody) in solution to antibody (or antigen) immobilized on a biosensor surface is analyzed within a fractal framework. The fit obtained by a dual-fractal analysis is compared with that obtained from a single-fractal analysis. In some cases, the dual-fractal analysis provides an improved fit when compared with a single-fractal analysis. This was indicated by the regression analysis provided by Sigmaplot (San Rafael, CA). These examples are presented. It is of interest to note that the state of disorder (or the fractal dimension) and the binding rate coefficient both increase (or decrease, a single example is presented for this case) as the reaction progresses on the biosensor surface. For example, for the binding of monoclonal antibody MAb 49 in solution to surface-immobilized antigen, a 90.4% increase in the fractal dimension (Df1 to Df2) from 1.327 to 2.527 leads to an increase in the binding rate coefficient (k1 to k2) by a factor of 9.4 from 11.74 to 110.3. The different examples analyzed and presented together provide a means by which the antigen-antibody reactions may be better controlled by noting the magnitude of the changes in the fractal dimension and in the binding rate coefficient as the reaction progresses on the biosensor surface.

Antigen-Antibody Reactions↗
PubMed1988

Effect of internalization and degradation of insulin on rat adipocyte insulin receptor binding kinetics.

We have assessed the influence of nondisplaceable (internalized) insulin and insulin degradation during binding reactions at 37 degrees C on the numbers and affinities of insulin binding sites on isolated rat adipocytes. Corrections for nondisplaceable insulin caused a 33% reduction in the number of the high affinity sites (p less than 0.01) and a 24% reduction (p less than 0.01) in the number of the low affinity sites which was associated with a 20% increase (p less than 0.01) in affinity when a two-site model was applied. With a one-site model, the number of insulin receptors decreased by approximately 33% (p less than 0.01), but the affinity did not change. These results indicate that the internalization and degradation of insulin that occurs during the binding reaction can significantly affect the estimation of insulin binding kinetics. Potential variations in internalization and degradation of insulin by cells obtained under various physiological or pathologic conditions should, therefore, be taken into consideration in the interpretation of insulin binding data.

Adipose Tissue↗
PubMed1998

Analyte-Receptor Binding Kinetics for Biosensor Applications: A Single-Fractal and a Dual-Fractal Analysis of the Influence of the Fractal Dimension on the Binding Rate Coefficient.

The diffusion-limited binding kinetics of antigen (analyte) in solution to antibody (receptor) immobilized on a biosensor surface is analyzed within a fractal framework. Most of the data presented are adequately described by a single-fractal analysis. This was indicated by the regression analysis provided by Sigmaplot ("Scientific Graphing Procedure, User's Manual," Jandel Scientific, San Rafael, CA, 1993). A couple of examples of a dual-fractal analysis are also presented. It is of interest to note that the binding rate coefficient and the fractal dimension both exhibit changes in the same direction for the analyte-receptor systems analyzed. Binding rate coefficient expressions as a function of the fractal dimension developed for the analyte-receptor binding systems indicate the high sensitivity of the binding rate coefficient on the fractal dimension when both a single- and a dual-fractal analysis are used. For example, for a single-fractal analysis and for the binding of cell surface proteins from Helicobacter pylori strain in solution to sialyl-(alpha-2,3)-lactose-conjugated (20 mol%) polyacrylamide immobilized on a resonant mirror biosensor (S. Hirmo et al., Anal. Biochem. 257, 63, 1998), the order of dependence of the binding rate coefficient, k, on the fractal dimension, Df, was 14.15. The fractional order of dependence of the binding rate coefficient(s) on the fractal dimension(s) further reinforces the fractal nature of the system. The binding rate coefficient(s) expressions developed as a function of the fractal dimension(s) are of particular value since they provide a means to better control biosensor performance by linking it to the heterogeneity on the surface and further emphasize in a quantitative sense the importance of the nature of the surface in biosensor performance. Copyright 1998 Academic Press.

Journal Article↗
PubMed2000

Binding kinetics of calbindin-D(28k) determined by flash photolysis of caged Ca(2+)

We have used UV flash photolysis of DM-nitrophen in combination with model-based analysis of Oregon Green 488 BAPTA-5N fluorescence transients to study the kinetics of Ca(2+) binding to calbindin-D(28K). The experiments used saturated DM-nitrophen at a [Ca(2+)] of 1.5 microM. Under these conditions, UV laser flashes produced rapid steplike increases in [Ca(2+)] in the absence of calbindin-D(28K), and in its presence the decay of the flash-induced fluorescence was due solely to the Ca(2+) buffering by the protein. We developed a novel method for kinetic parameter derivation and used the synthetic Ca(2+) buffer EGTA to confirm its validity. We provide evidence that calbindin-D(28K) binds Ca(2+) in at least two distinct kinetic patterns, one arising from high-affinity sites that bind Ca(2+) with a k(on) comparable to that of EGTA (i.e., approximately 1 x 10(7) M(-1) s(-1)) and another with lower affinity and an approximately eightfold faster k(on). In view of the inability of conventional approaches to adequately resolve rapid Ca(2+) binding kinetics of Ca(2+) buffers, this method promises to be highly valuable for studying the Ca(2+) binding properties of other biologically important Ca(2+) binding proteins.

Acetates↗
PubMed1996

Quaternary structure dynamics and carbon monoxide binding kinetics of hemoglobin valency hybrids.

The kinetics of CO binding and changes in quaternary structure for symmetric valency hybrids of human hemoglobin have been extensively studied by laser photolysis techniques. Both alpha+beta and alpha beta+ hybrids were studied with five different ferric ligands, over a broad range of CO concentrations and photolysis levels. After full CO photolysis, the hybrid tetramers switch extensively and rapidly (< 200 microseconds) to the T quaternary structure. Both R --> T and T --> R transition rates for valency hybrid tetramers with 0 and 1 bound CO have been obtained, as well as the CO association rates for alpha and beta subunits in the R and T states. The results reveal submillisecond R reversible T interconversion, and, for the first time, the changes in quaternary rates and equilibria due to binding a single CO per tetramer have been resolved. The data also show significant alpha-beta differences in quaternary dynamics and equilibria. The allosteric constants do not vary with the spin states of the ferric subunits as predicted by the Perutz stereochemical model. For the alpha beta+CN hybrid the kinetics are heterogeneous and imply partial conversion to a T-like state with very low (seconds) R reversible T interconversion.

Allosteric Regulation↗
PubMed1984

Binding kinetics of monomeric and aggregated IgG to Kupffer cells and hepatocytes of mice.

The binding kinetics of human monomeric IgG and stable heat-aggregated IgG (A-IgG) to Fc receptors of hepatocytes and Kupffer cells isolated from mice was studied. After injection of radiolabelled proteins the 60-70% of hepatic uptake was recovered in parenchymal cells (hepatocytes). In experiments in vitro the A-IgG bound in larger amounts to hepatocytes and Kupffer cells than monomeric IgG. The association rate constants of aggregates were somewhat higher for Kupffer cells than for hepatocytes whereas the percentage uptake of aggregates by Kupffer cells was only 5-15% of that of hepatocytes. The equilibrium constants of aggregates binding to both cells amounted to 0.4-1 X 10(8) M-1 for A-IgG compared with an equilibrium constant for monomeric IgG of 1-2 X 10(7)M-1. The maximum number of IgG and A-IgG molecules bound per cell was higher on hepatocytes (mean 14 X 10(6)) than on Kupffer cells (mean 2 X 10(5)) which is in agreement with the higher binding capacity of hepatocytes for these proteins observed in vivo and in vitro experiments. The ability to compete for receptor binding seemed to reside exclusively in the Fc portion of IgG since F(ab')2 fragments of IgG failed to inhibit labelled monomeric IgG or A-IgG. The receptor seems to be specific for IgG since unlabelled monomeric IgA demonstrated no binding inhibition of labelled IgG or A-IgG on hepatocytes and Kupffer cells. The overall results further suggest that hepatocytes might through Fc receptors play a collaborative role with the mononuclear phagocytic system in the clearance of circulating immune complexes.

Animals↗
PubMed1995

Nucleotide-free actin: stabilization by sucrose and nucleotide binding kinetics.

We prepared nucleotide-free actin in buffer containing 48% (w/v) sucrose. Sucrose inhibits the irreversible denaturation of actin that follows nucleotide dissociation [Kasai et al. (1965) Biochim. Biophys. Acta 94, 494-503]. Our conditions removed nucleotide from approximately 80% of the actin. Stabilization of nucleotide-free actin depends on the sucrose concentration. The CD ellipticity (x 10(3) deg cm2 dmol-1) at 222 nm of nucleotide-free actin in 48% sucrose is -3.54. The ellipticity of denatured nucleotide-free actin in dilute buffer is -2.01 and that of native actin is -4.19. In 48% sucrose nucleotide-free actin has 1.12 and native actin has 0.5 solvent-exposed thiol residues. The conformation of native actin is recovered when ATP and Mg2+ are added. Our ability to generate stable nucleotide-free actin permitted us to study the kinetics of nucleotide binding to actin. The observed rate constant of the reaction is linearly dependent on the concentration of epsilon ATP, a fluorescent analog of ATP. The inverse of the association rate constant is proportional to the viscosity of the solvent with an intercept near the origin as expected for a diffusion-limited reaction. The second-order association rate constant for Mg(2+)-ATP and Ca(2+)-ATP binding to nucleotide-free actin in water at 22 degrees C is 5 x 10(6) M-1 s-1. The Smoluchowski collision rate constant for actin and ATP is calculated to be 6.5 x 10(9) M-1 s-1, which makes the "orientation factor" 7.7 x 10(-4). From the ratio of the dissociation and association rate constants, we calculate dissociation equilibrium constants of 1.2 x 10(-9) M for Mg(2+)-ATP-actin, 4.4 x 10(-9) M for Mg(2+)-epsilon ATP-actin, and 1.2 x 10(-10) M for Ca(2+)-ATP-actin.

Actins↗
PubMed2006

Molecular microfluorometry: converting arbitrary fluorescence units into absolute molecular concentrations to study binding kinetics and stoichiometry in transporters.

Cotransporters use energy stored in Na+ or H+ gradients to transport neurotransmitters or other substrates against their own gradient. Cotransport is rapid and efficient, and at synapses it helps terminate signaling. Cotransport in norepinephrine (NET), epinephrine (EpiT), dopamine (DAT), and serotonin (SERT) transporters couples downhill Na+ flux to uphill transmitter flux. NETs, for example, attenuate signaling at adrenergic synapses by efficiently clearing NE from the synaptic cleft, thus preparing the synapse for the next signal. Transport inhibition with tricyclic antidepressants prolongs neurotransmitter presence in the synaptic cleft, potentially alleviating symptoms of depression. Transport inhibition with cocaine or amphetamine, which respectively block or replace normal transport, may result in hyperactivity. Little is known about the kinetic interactions of substrates or drugs with transporters, largely because the techniques that have been successful in discovering trans- porter agonists and antagonists do not yield detailed kinetic information. Mechanistic data are for the most part restricted to global parameters, such as Km and Vmax, measured from large populations of transporter molecules averaged over thousands of cells. Three relatively new techniques used in transporter research are electrophysiology, amperometry, and microfluorometry. This review focuses on fluorescence-based methodologies, which--unlike any other technique-permit the simultaneous measurement of binding and transport. Microfluorometry provides unique insights into binding kinetics and transport mechanisms from a quantitative analysis of fluorescence data. Here we demonstrate how to quantify the number of bound substrate molecules, the number of transported substrate molecules, and the kinetics of substrate binding to individual transporters. Although we describe experiments on a specific neurotransmitter transporter, these methods are applicable to other membrane proteins.

Adrenergic Uptake Inhibitors↗
PubMed1989

Binding kinetics of mutated insulin receptors in transfected cells grown in suspension culture: application to the Tyr----Phe 960 insulin receptor mutant.

Site-directed mutagenesis of the insulin receptor cDNA is now widely used to elucidate the role of various domains and residues of the receptor, particularly in order to examine the functional importance of the beta chain-associated tyrosine kinase. However, little has been done to correlate the functional repercussions of such mutations with alterations in the complex insulin binding kinetics. This is due in part to the difficulty of conducting large scale experiments using transfected cells on culture dishes. In an effort to overcome this problem, we have developed a method for culturing Chinese hamster ovary (CHO) cells in suspension culture, which provides a large number of cells and obviates the need for enzymatic or mechanical detachment of cells. The feasibility of this approach is demonstrated in a detailed study of the kinetics of insulin binding to the Tyr----Phe 960 insulin receptor mutant.

Animals↗
PubMed2001

Effect of depolarization on binding kinetics of scorpion alpha-toxin highlights conformational changes of rat brain sodium channels.

Binding of scorpion alpha-toxins to receptor site 3 on voltage-gated sodium channels inhibits sodium current inactivation and is voltage-dependent. To reveal the direct effect of depolarization, we analyzed binding kinetics of the alpha-toxin Lqh-II (from Leiurus quinquestriatus hebraeus) to rat brain synaptosomes and effects on rat brain II (rBII) channels expressed in mammalian cells. Our results indicated that the 33-fold decrease in toxin affinity for depolarized (0 mV, 90 mM [K(+)](out), K(d) = 5.85 +/- 0.5 nM) versus polarized (-55 mV, 5 mM [K(+)](out), K(d) = 0.18 +/- 0.04 nM) synaptosomes at steady state results from a 48-fold reduction in the association rate (k(on) at 5 mM [K(+)] = (12.0 +/- 4) x 10(6) M(-1) s(-1) and (0.25 +/- 0.03) x 10(6) M(-1) s(-1) at 90 mM [K(+)](out)) with nearly no change in the dissociation rate. Electrophysiological analyses of rBII channels expressed in mammalian cells revealed that approximately 75% and 40% of rBII occupied fast- and slow-inactivated states, respectively, at resting membrane potential of synaptosomes (-55 mV), and Lqh-II markedly increased the steady-state fast and slow inactivation. To mimic electrophysiological conditions we induced fast depolarization of toxin-bound synaptosomes, which generated a biphasic unbinding of Lqh-II from toxin-receptor complexes. The first fast off rate closely resembled values determined electrophysiologically for rBII in mammalian cells. The second off rate was similar to the voltage-independent steady-state value, attributed to binding to the slow-inactivated channel states. Thus, the Lqh-II voltage-dependent affinity highlights two independent mechanisms representing conformational changes of sodium channels associated with transitions among electrically visible and invisible inactivated states.

Animals↗
PubMed1995

Human platelet Fc receptors: binding kinetics of Fc derivatives to the receptors.

Human platelets are known to carry Fc receptors (Fc R), but the binding characteristics between ligands and Fc gamma R has not been well elucidated. In this study, we investigated the binding kinetics of IgG Fc fragments (Fc) to Fc R, the association and dissociation characteristics of the ligands to and from Fc gamma R using enzymatically modified Fc fragment derivatives. Approximately 60 minutes and 90 minutes were needed at 37 degrees C and 22 degrees C, respectively, for complete saturation of the Fc binding sites with horseradish peroxidase-conjugated Fc (HPO-Fc). Heat aggregated IgG (HAG) had a greater affinity for the Fc gamma R than Fc monomers. Additional binding of HAG was observed even after the binding sites were saturated with Fc monomers. This could be explained by different binding sites available only for immune complexes or by the partial dissociation of binding sites saturated with Fc by HAG. Further, we noted partial dissociation of HPO-Fc, when HAG was added after saturation of the binding sites with HPO-Fc. In a subsequent experiment, we compared the relative affinities of chemically or enzymatically modified Fc derivatives for Fc gamma R. HAG, which was used as a model for CIC, had a greater affinity for platelet Fc gamma R than IgG monomer and Fc derivatives. Pepsin-digestion of Fc caused a total loss of its affinity for the Fc gamma R, whereas b-mercaptoethanol-treated Fc fragments demonstrated substantial binding to the Fc gamma R. These results indicate that the pepsin digestion affects the Fc portion and causes a disruption in the area of the Fc which is essential for the recognition by the platelet Fc gamma R. On the other hand, cleavage of disulfide bridges by beta-mercaptoethanol resulted in a marked increase in affinity for the Fc gamma R. On the other hand, enzymatic cleavage of the carbohydrate moieties of Fc did not alter the affinity of Fc fragments for the Fc gamma R, indicating that the carbohydrates play an insignificant role or are not involved in their binding to the Fc gamma R.

Binding Sites↗
PubMed2006

The effects of nucleotides on MutS-DNA binding kinetics clarify the role of MutS ATPase activity in mismatch repair.

MutS protein initiates mismatch repair with recognition of a non-Watson-Crick base-pair or base insertion/deletion site in DNA, and its interactions with DNA are modulated by ATPase activity. Here, we present a kinetic analysis of these interactions, including the effects of ATP binding and hydrolysis, reported directly from the mismatch site by 2-aminopurine fluorescence. When free of nucleotides, the Thermus aquaticus MutS dimer binds a mismatch rapidly (k(ON)=3 x 10(6) M(-1) s(-1)) and forms a stable complex with a half-life of 10 s (k(OFF)=0.07 s(-1)). When one or both nucleotide-binding sites on the MutS*mismatch complex are occupied by ATP, the complex remains fairly stable, with a half-life of 5-7 s (k(OFF)=0.1-0.14 s(-1)), although MutS(ATP) becomes incapable of (re-)binding the mismatch. When one or both nucleotide-binding sites on the MutS dimer are occupied by ADP, the MutS*mismatch complex forms rapidly (k(ON)=7.3 x 10(6) M(-1) s(-1)) and also dissociates rapidly, with a half-life of 0.4 s (k(OFF)=1.7 s(-1)). Integration of these MutS DNA-binding kinetics with previously described ATPase kinetics reveals that: (a) in the absence of a mismatch, MutS in the ADP-bound form engages in highly dynamic interactions with DNA, perhaps probing base-pairs for errors; (b) in the presence of a mismatch, MutS stabilized in the ATP-bound form releases the mismatch slowly, perhaps allowing for onsite interactions with downstream repair proteins; (c) ATP-bound MutS then moves off the mismatch, perhaps as a mobile clamp facilitating repair reactions at distant sites on DNA, until ATP is hydrolyzed (or dissociates) and the protein turns over.

2-Aminopurine↗
PubMed1995

Binding kinetics of ecotropic (Moloney) murine leukemia retrovirus with NIH 3T3 cells.

A quantitative analysis of the binding kinetics of intact Moloney murine leukemia retrovirus (MoMuLV) particles with NIH 3T3 cells was performed with an immunofluorescence flow cytometry assay. The virus-cell binding equilibrium dissociation constant (KD), expressed in terms of virus particle concentration, was measured to be 8.5 (+/- 6.4) x 10(-12) M at 4 degrees C and was three- to sixfold lower at temperatures above 15 degrees C. The KD of virus binding is about 1,000-fold lower than the KD of purified MoMuLV envelope. The association rate constant was determined to be 2.5 (+/- 0.9) x 10(9) M-1 min-1 at 4 degrees C and was 5- to 10-fold higher at temperatures above 15 degrees C. The apparent dissociation rate constant at 4 degrees C was 1.1 (+/- 0.4) x 10(-3) min-1 and was doubled for every 10 degrees C increase in temperature over the range tested (15 to 37 degrees C).

3T3 Cells↗
PubMed1986

Analytical affinity chromatography. II. Rate theory and the measurement of biological binding kinetics.

Affinity chromatography can be used to measure equilibrium constants and kinetics of biological interactions. The local-equilibrium theory presented in the preceding paper is extended to include mass transfer and kinetic effects. Solutions for both zonal and frontal elution are presented. For highly nonlinear isotherms, the frontal elution method is preferred. Experiments with bovine serum albumin binding to immobilized Reactive Blue show that the binding kinetics inside the porous gel are several orders of magnitude slower than typical biological binding reactions in solution. The temperature dependence of the kinetic constants indicate that the binding may still be diffusion-controlled.

Animals↗
PubMed1994

Binding kinetics of ATP gamma S35 on cultured primary tracheal surface epithelial cells.

Extracellular ATP can stimulate mucin release from primary hamster tracheal surface epithelial (HTSE) cells via a P2 purinoceptor-mediated mechanism, based on agonist potency studies of mucin release (Br. J. Pharmacol. 1991; 103:1053-1056). In the present study, we examined the kinetics of ATP binding to the surface of intact HTSE cells at 4 degrees C using ATP gamma S35 as a radioligand. We found that ATP gamma S35 bound to HTSE cells in a saturable, reversible manner, reaching an equilibrium at about 30 min. Scatchard analysis of equilibrium binding suggested the presence of two binding sites with Kd values of 0.47 and 9.4 microM. Competitive binding experiments, based on the ability of nucleotides and ATP analogs to block ATP gamma S35 revealed a rank order of ATP > ADP > alpha,beta-methylene ATP > 2-methylthio ATP > or = beta, gamma-methylene ATP. Neither AMP nor adenosine could inhibit the ATP gamma S35 binding. A comparison between the ability of nucleotides to compete with ATP gamma S35 binding and their ability to induce mucin release revealed a rather poor correlation (r2 = 0.67) with all of the above nucleotides but a good correlation (r2 = 0.96) without 2-methylthio ATP, indicating the presence of heterogenous ATP binding sites on the HTSE cell surface. UTP, a pyrimidine nucleotide, which is almost equipotent with ATP in its ability to stimulate mucin release, was much less potent than ATP in its ability to displace the ATP gamma S35 binding in these HTSE cells.

Adenine Nucleotides↗
PubMed1996

Antigen-antibody diffusion-limited binding kinetics for biosensors. A fractal analysis.

A fractal analysis is made for antigen-antibody binding kinetics for different biosensor applications available in the literature. Both types of examples are considered wherein: (1) the antigen is in solution and the antibody is immobilized on the fiberoptic surface, and (2) the antibody is in solution and the antigen is immobilized on the fiberoptic surface. For example, when the antibody is immobilized on the surface, an increase in the antigen Clostridium botulinum toxin A concentration in solution leads to (1) a decrease in the fractal dimension value or state of disorder, and (2) a higher rate constant for binding on the fiberoptic surface. An analysis of the effect of the influence of different parameters on the fractal dimension values for a particular example, such as varying treatments or incubation procedures, helps provide insights into the conformational states and reactions occurring on the fiberoptic surface. The analysis of the different example taken together provides novel physical insights into the state of "disorder" and reactions occurring on the surface. Such types of analysis should help contribute toward manipulating the reactions occurring on the fiberoptic surfaces in desired directions.

Antigen-Antibody Reactions↗
PubMed1995

Antigen-antibody diffusion-limited binding kinetics of biosensors: a fractal analysis.

A fractal analysis is made of antigen-antibody binding kinetics in various biosensor applications reported in the literature. Both sensor configurations are considered, wherein (a) the antigen is in solution and the antibody is immobilized on the fibre-optic surface, and (b) the antibody is in solution and the antigen is immobilized on the fibre-optic surface. For example, when the antigen is immobilized, an increase in the antibody concentration (anti-Ars) in solution leads to (a) an increase in the fractal dimension value and hence the state of disorder or roughness, and (b) a higher rate coefficient for binding on the fibre-optic surface. An analysis of the influence of different parameters on the fractal dimension values for a particular effect, such as a comparison of fresh and regenerated immunosensors, helps to clarify the conformational states and reactions occurring on the fibre-optic surface. Examination of the different cases presented together provides novel physical insights into the state of disorder or roughness on the surface. This research should contribute towards techniques for manipulating the reactions occurring on fibre-optic surfaces in desired directions.

Antigen-Antibody Reactions↗
PubMed1999

Analyte-receptor binding kinetics for different types of biosensors. A fractal analysis.

A fractal analysis is presented for analyte-receptor binding kinetics for different types of biosensor applications. Data taken from the literature may be modeled using a single-fractal analysis, a single- and a dual-fractal analysis, or a dual-fractal analysis. The latter two methods represent a change in the binding mechanism as the reaction progresses on the surface. Predictive relationships developed for the binding rate coefficient as a function of the analyte concentration are of particular value since they provide a means by which the binding rate coefficients may be manipulated. Relationships are presented for the binding rate coefficients as a function of the fractal dimension Df or the degree of heterogeneity that exists on the surface. When analyte-receptor binding is involved, an increase in the heterogeneity on the surface (increase in Df) leads to an increase in the binding rate coefficient. It is suggested that an increase in the degree of heterogeneity on the surface leads to an increase in the turbulence on the surface owing to the irregularities on the surface. This turbulence promotes mixing, minimizes diffusional limitations, and leads subsequently to an increase in the binding rate coefficient. The binding rate coefficient is rather sensitive to the degree of heterogeneity, Df, that exists on the biosensor surface. For example, the order of dependence on Df1 is 7.25 for the binding rate coefficient k1 for the binding of a Fab fragment of an antiparaquat monoclonal antibody in solution to an antigen in the form of a paraquat analog immobilized on a sensor surface. The predictive relationships presented for the binding rate coefficient and the fractal dimension as a function of the analyte concentration in solution provide further physical insights into the binding reactions on the surface, and should assist in enhancing biosensor performance. In general, the technique is applicable to other reactions occurring on different types of surfaces, such as cell-surface reactions.

Biosensing Techniques↗