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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

Complementary measurements for E. coli total lipid extract liposomes adsorbing to TiO2 in the presence of 1 mM CaCl2. (a) QCM-D frequency (wet mass) and dissipation; (b) OWLS (dry) mass; (c) Fluorescence recovery after photobleaching of a spot in the adsorbed film; (d) Comparison of no adsorption of serum after addition to the adsorbed film on TiO2 (Δf, open squares; ΔD filled squares) compared to significant adsorption for the partial SLB formed on SiO2 (Δf, open circles; ΔD filled circles) under the same conditions; (e) Probable conformation of the adsorbed lipid film by comparison of the complementary measurements: a non-planar SLB. Reused with permission of Merz, C.; Knoll, W.; Textor, M.; Reimhult, E. [98], adapted from Figure 3 in “Formation of supported bacterial lipid membrane mimics”, Biointerphases2008, 3, FA41–FA50. Copyright 2008 AVS. The Science & Technology Society, and with kind permission of Springer Science+Business Media B.V.
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biosensors-02-00341-f011: Complementary measurements for E. coli total lipid extract liposomes adsorbing to TiO2 in the presence of 1 mM CaCl2. (a) QCM-D frequency (wet mass) and dissipation; (b) OWLS (dry) mass; (c) Fluorescence recovery after photobleaching of a spot in the adsorbed film; (d) Comparison of no adsorption of serum after addition to the adsorbed film on TiO2 (Δf, open squares; ΔD filled squares) compared to significant adsorption for the partial SLB formed on SiO2 (Δf, open circles; ΔD filled circles) under the same conditions; (e) Probable conformation of the adsorbed lipid film by comparison of the complementary measurements: a non-planar SLB. Reused with permission of Merz, C.; Knoll, W.; Textor, M.; Reimhult, E. [98], adapted from Figure 3 in “Formation of supported bacterial lipid membrane mimics”, Biointerphases2008, 3, FA41–FA50. Copyright 2008 AVS. The Science & Technology Society, and with kind permission of Springer Science+Business Media B.V.

Mentions: Figure 11(a) shows the QCM-D kinetics for adsorption of E. coli total lipid extract liposomes to TiO2 in the presence of 1 mM CaCl2 [98]. Under these conditions a comparison of the kinetics with the established kinetics for SLB formation shown in Figure 8, seems to indicate that here we are observing a process that starts as SLB formation, but then diverges and displays a continuous increase in mass and dissipation of the adsorbed layer. This increase seems to continue even after excess liposomes have been removed from the bulk solution. The result seems to indicate an ever more extended film coupled to the sensor substrate.


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

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

Complementary measurements for E. coli total lipid extract liposomes adsorbing to TiO2 in the presence of 1 mM CaCl2. (a) QCM-D frequency (wet mass) and dissipation; (b) OWLS (dry) mass; (c) Fluorescence recovery after photobleaching of a spot in the adsorbed film; (d) Comparison of no adsorption of serum after addition to the adsorbed film on TiO2 (Δf, open squares; ΔD filled squares) compared to significant adsorption for the partial SLB formed on SiO2 (Δf, open circles; ΔD filled circles) under the same conditions; (e) Probable conformation of the adsorbed lipid film by comparison of the complementary measurements: a non-planar SLB. Reused with permission of Merz, C.; Knoll, W.; Textor, M.; Reimhult, E. [98], adapted from Figure 3 in “Formation of supported bacterial lipid membrane mimics”, Biointerphases2008, 3, FA41–FA50. Copyright 2008 AVS. The Science & Technology Society, and with kind permission of Springer Science+Business Media B.V.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

biosensors-02-00341-f011: Complementary measurements for E. coli total lipid extract liposomes adsorbing to TiO2 in the presence of 1 mM CaCl2. (a) QCM-D frequency (wet mass) and dissipation; (b) OWLS (dry) mass; (c) Fluorescence recovery after photobleaching of a spot in the adsorbed film; (d) Comparison of no adsorption of serum after addition to the adsorbed film on TiO2 (Δf, open squares; ΔD filled squares) compared to significant adsorption for the partial SLB formed on SiO2 (Δf, open circles; ΔD filled circles) under the same conditions; (e) Probable conformation of the adsorbed lipid film by comparison of the complementary measurements: a non-planar SLB. Reused with permission of Merz, C.; Knoll, W.; Textor, M.; Reimhult, E. [98], adapted from Figure 3 in “Formation of supported bacterial lipid membrane mimics”, Biointerphases2008, 3, FA41–FA50. Copyright 2008 AVS. The Science & Technology Society, and with kind permission of Springer Science+Business Media B.V.
Mentions: Figure 11(a) shows the QCM-D kinetics for adsorption of E. coli total lipid extract liposomes to TiO2 in the presence of 1 mM CaCl2 [98]. Under these conditions a comparison of the kinetics with the established kinetics for SLB formation shown in Figure 8, seems to indicate that here we are observing a process that starts as SLB formation, but then diverges and displays a continuous increase in mass and dissipation of the adsorbed layer. This increase seems to continue even after excess liposomes have been removed from the bulk solution. The result seems to indicate an ever more extended film coupled to the sensor substrate.

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