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Using complementary acoustic and optical techniques for quantitative monitoring of biomolecular adsorption at interfaces.

Konradi R, Textor M, Reimhult E - Biosensors (Basel) (2012)

Bottom Line: In this tutorial review, different optical and acoustic evanescent techniques are used to illustrate how an understanding of the transducer principle of each technique can be exploited for further interpretation of hydrated and extended polymer and biological films.The case studies deal with representative examples of adsorption of protein films, polymer brushes and lipid membranes, and describe e.g., how to deal with strongly vs. weakly hydrated films, large conformational changes and ordered layers of biomolecules.The presented systems and methods are compared to other representative examples from the increasing literature on the subject.

View Article: PubMed Central - PubMed

Affiliation: BASF SE, Advanced Materials and Systems Research, D-67056 Ludwigshafen, Germany. rupert.konradi@basf.com.

ABSTRACT
The great wealth of different surface sensitive techniques used in biosensing, most of which claim to measure adsorbed mass, can at first glance look unnecessary. However, with each technique relying on a different transducer principle there is something to be gained from a comparison. In this tutorial review, different optical and acoustic evanescent techniques are used to illustrate how an understanding of the transducer principle of each technique can be exploited for further interpretation of hydrated and extended polymer and biological films. Some of the most commonly used surface sensitive biosensor techniques (quartz crystal microbalance, optical waveguide spectroscopy and surface plasmon resonance) are briefly described and five case studies are presented to illustrate how different biosensing techniques can and often should be combined. The case studies deal with representative examples of adsorption of protein films, polymer brushes and lipid membranes, and describe e.g., how to deal with strongly vs. weakly hydrated films, large conformational changes and ordered layers of biomolecules. The presented systems and methods are compared to other representative examples from the increasing literature on the subject.

No MeSH data available.


Related in: MedlinePlus

In situ investigation of PLL-g-PMOXA (α = 0.22) copolymer adsorption and serum exposure by (a) optical waveguide lightmode spectroscopy (OWLS) and (b) quartz crystal microbalance (QCM-D). Nb2O5-coated waveguides and quartz crystals were first incubated with the polymer in a physiological buffer solution (10 mM HEPES + 150 mM NaCl adjusted to pH 7.4) and then exposed to full human blood serum for 15 min. The surfaces were rinsed with buffer before and after each adsorption step. In (b) the ‘wet’ mass (—) is calculated from the inversely proportional normalized frequency shift by using the Sauerbrey relation, Equation (3). The increase in dissipation (—) upon polymer adsorption is related to an increased viscoelasticity of the adlayer. The kinks in the curves are due to temperature instabilities upon solution injection.
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biosensors-02-00341-f005: In situ investigation of PLL-g-PMOXA (α = 0.22) copolymer adsorption and serum exposure by (a) optical waveguide lightmode spectroscopy (OWLS) and (b) quartz crystal microbalance (QCM-D). Nb2O5-coated waveguides and quartz crystals were first incubated with the polymer in a physiological buffer solution (10 mM HEPES + 150 mM NaCl adjusted to pH 7.4) and then exposed to full human blood serum for 15 min. The surfaces were rinsed with buffer before and after each adsorption step. In (b) the ‘wet’ mass (—) is calculated from the inversely proportional normalized frequency shift by using the Sauerbrey relation, Equation (3). The increase in dissipation (—) upon polymer adsorption is related to an increased viscoelasticity of the adlayer. The kinks in the curves are due to temperature instabilities upon solution injection.

Mentions: Figure 5 shows typical OWLS (a) and QCM-D (b) experiments for PLL-g-PMOXA of medium grafting density. In both cases, first the polymer adsorption was followed in situ until a stable layer had formed. Subsequently, after rinsing with buffer, the surfaces were exposed to full human serum (control serum, Precinorm® U, LOT: 171 074-01, reconstituted in ultrapure water) for 15 min and rinsed again with buffer. Comparison of the mass values of the polymer coating equilibrated with buffer solution before and after serum exposure allows the researcher to quantify the adsorbed serum mass.


Using complementary acoustic and optical techniques for quantitative monitoring of biomolecular adsorption at interfaces.

Konradi R, Textor M, Reimhult E - Biosensors (Basel) (2012)

In situ investigation of PLL-g-PMOXA (α = 0.22) copolymer adsorption and serum exposure by (a) optical waveguide lightmode spectroscopy (OWLS) and (b) quartz crystal microbalance (QCM-D). Nb2O5-coated waveguides and quartz crystals were first incubated with the polymer in a physiological buffer solution (10 mM HEPES + 150 mM NaCl adjusted to pH 7.4) and then exposed to full human blood serum for 15 min. The surfaces were rinsed with buffer before and after each adsorption step. In (b) the ‘wet’ mass (—) is calculated from the inversely proportional normalized frequency shift by using the Sauerbrey relation, Equation (3). The increase in dissipation (—) upon polymer adsorption is related to an increased viscoelasticity of the adlayer. The kinks in the curves are due to temperature instabilities upon solution injection.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263558&req=5

biosensors-02-00341-f005: In situ investigation of PLL-g-PMOXA (α = 0.22) copolymer adsorption and serum exposure by (a) optical waveguide lightmode spectroscopy (OWLS) and (b) quartz crystal microbalance (QCM-D). Nb2O5-coated waveguides and quartz crystals were first incubated with the polymer in a physiological buffer solution (10 mM HEPES + 150 mM NaCl adjusted to pH 7.4) and then exposed to full human blood serum for 15 min. The surfaces were rinsed with buffer before and after each adsorption step. In (b) the ‘wet’ mass (—) is calculated from the inversely proportional normalized frequency shift by using the Sauerbrey relation, Equation (3). The increase in dissipation (—) upon polymer adsorption is related to an increased viscoelasticity of the adlayer. The kinks in the curves are due to temperature instabilities upon solution injection.
Mentions: Figure 5 shows typical OWLS (a) and QCM-D (b) experiments for PLL-g-PMOXA of medium grafting density. In both cases, first the polymer adsorption was followed in situ until a stable layer had formed. Subsequently, after rinsing with buffer, the surfaces were exposed to full human serum (control serum, Precinorm® U, LOT: 171 074-01, reconstituted in ultrapure water) for 15 min and rinsed again with buffer. Comparison of the mass values of the polymer coating equilibrated with buffer solution before and after serum exposure allows the researcher to quantify the adsorbed serum mass.

Bottom Line: In this tutorial review, different optical and acoustic evanescent techniques are used to illustrate how an understanding of the transducer principle of each technique can be exploited for further interpretation of hydrated and extended polymer and biological films.The case studies deal with representative examples of adsorption of protein films, polymer brushes and lipid membranes, and describe e.g., how to deal with strongly vs. weakly hydrated films, large conformational changes and ordered layers of biomolecules.The presented systems and methods are compared to other representative examples from the increasing literature on the subject.

View Article: PubMed Central - PubMed

Affiliation: BASF SE, Advanced Materials and Systems Research, D-67056 Ludwigshafen, Germany. rupert.konradi@basf.com.

ABSTRACT
The great wealth of different surface sensitive techniques used in biosensing, most of which claim to measure adsorbed mass, can at first glance look unnecessary. However, with each technique relying on a different transducer principle there is something to be gained from a comparison. In this tutorial review, different optical and acoustic evanescent techniques are used to illustrate how an understanding of the transducer principle of each technique can be exploited for further interpretation of hydrated and extended polymer and biological films. Some of the most commonly used surface sensitive biosensor techniques (quartz crystal microbalance, optical waveguide spectroscopy and surface plasmon resonance) are briefly described and five case studies are presented to illustrate how different biosensing techniques can and often should be combined. The case studies deal with representative examples of adsorption of protein films, polymer brushes and lipid membranes, and describe e.g., how to deal with strongly vs. weakly hydrated films, large conformational changes and ordered layers of biomolecules. The presented systems and methods are compared to other representative examples from the increasing literature on the subject.

No MeSH data available.


Related in: MedlinePlus