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Application examples:
LB film characterization in air
Creating ordered single or multiple layers of molecules
has a multitude of technology applications in, for instance,
biosensors and nanoelectronics etc. In this example, Langmuir-Blodgett
deposition was used to deposit single and multiple layers
of stearic acid on gold. By measuring the full SPR intensity
versus angle curves in air, the layer thickness after successive
depositions could be quickly and easily confirmed. In this
case, the film thickness increased linearly with the number
of layers.
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"Precise control of Langmuir-Blodgett film thickness"
SPR intensity versus angle
curves measured in air for an increasing number of LB
layers of Stearic Acid on gold.
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Albumin adsorption
A typical application in biomaterials research is the adsorption
of protein to tailored surfaces. In this case, KSV SPR 200 was used
to follow the adsorption of 0.1 mg/mL Bovine Serum Albumin (BSA)
onto a gold surface before and after self-assembly of an alkanethiol.
The results show that hydrophobization of the gold halved the
amount of albumin adsorbed. The layer thickness and adsorbed amount
can be determined in each case, by fitting the measured data with
theory.
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"Highly sensitive measurements of protein adsorption on gold"
Change in SPR signal during
BSA adsorption to hydrophilic and hydrophobic gold.
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Characterization of Polyelectrolyte Multilayers
Polyelectrolyte multilayers (PEMs) are soft nanoscale films that are build by layer-by-layer (LbL) assembly in solution on a substrate. The KSV SPR 200 can be utilized to monitor the assembly in situ with full angular spectra, which enables collection of both kinetic information from the formation and layer thicknesses from a single experiment. The method can also be used with components that have complex refractive index, like metallic nanoparticles, making KSV SPR 200 a powerfull tool when studying functional coatings made by LbL method.
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"Monitoring of PEMs Layer-by-Layer assembly"
SPR-spectra of pure sensor slide in buffer (black) and with increasing number of PE-layers (blue).
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In Situ Monitoring of L-by-L assembly of MOFs
Metal organic frameworks (MOFs) have high potential for hydrogen storage, optics and catalysis. A MOF composed of copper and benzenetricarboxylic acid was synthesized and characterized in situ using the KSV SPR 200 with autosampler. The optical thickness of the material was obtained using the full angular spectra in both solvent and air. The optical thickness of the MOF was found to increase nearly linearly, and the increment to approach a constant value when adding layers. The experiment shows that the instrument is capable to measure materials with complex refractive indexes.
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"Monitoring of MOFs Layer-by-Layer assembly"
SPR sensograms of both fixed angle experiment (blue), and angular scan experiment (black).
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