Application examples:

AN117 Quantitative detection of genetic material

dNA assays can be applied for detecting genetic material in order to detect genetic disorders, mutations, gene transfection or species from a large variety of samples. By assaying specific single stranded oligonucleotides of over 20 nucleotides in length, it is possible to detect and quantify unique gene sequences from large amounts of genetic material. BioNavis SPR Navi 200 can be utilized easily into a dNA assay that can detect and quantify single-stranded oligonucleotides with high precision over a large concentration range from micro to nanomolar concentrations.

"Quantification of single stranded oligonucleotides with SPR Navi 200" Compilation of the sensograms from several different injections (upper graph) First order exponential fit to the bound amount of dNA (lower graph)

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AN109 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.

"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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AN120 Electrochemical SPR

Electrochemistry can be utilized as a detetion method or driving force for chemical reactions. Combining electrochemistry with SPR can be utilized in monitoring electrochemical reactions in situ, or it can be used as an additional detection method in order to produce additional data from measurements. As an example SPR Navi 200 with the electrochemical cell accessory was used in monitoring copper deposition on gold with cyclic voltametry in situ.

"In situ monitoring of electrochemical reactions using SPR Navi 200" SPR sensograms of copper deposition with cyclic voltametry using two different potential scanning rates.

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AN115 Measuring water content in thin films by SPR and QCM

It is possible to quantify the bound water content of nanoscale thin films by combining the two different techniques, SPR and QCM. In a QCM measurement in liquid media the mechanical QCM method detects mass changes that include any bound solvent molecules in the layer, while an optical SPR technique detects the mass differing from the bulk solution, meaning the dry mass of the layer. By combining these two techniques, water content of a thin layer can easily be quantified, which is shown in the example below.

"Determining amount of bound water in self adsorbed polymer layers on different surfaces by combination of SPR and QCM" Bound polymer mass measured by SPR on different surfaces and concentrations.

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AN111 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 SPR Navi 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 SPR Navi 200 a powerfull tool when studying functional coatings made by LbL method.

"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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AN112 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 SPR Navi 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.

"Monitoring of MOFs Layer-by-Layer assembly" SPR sensograms of both fixed angle experiment (blue), and angular scan experiment (black).

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AN110 Albumin adsorption

A typical application in biomaterials research is the adsorption of protein to tailored surfaces. In this case, SPR Navi 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.

"Highly sensitive measurements of protein adsorption on gold" Change in SPR signal during BSA adsorption to hydrophilic and hydrophobic gold.

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AN113 Quantitative Detection of Small Molecules

BioNavis SPR 200 was shown to have excellent performance with challenging small molecular weight samples, such as Dopamine. The high amount of non-specific interactions during injections did not affect the quantitative performance of the instrument. The method described can be easily adopted for other biochemical assays where low concentrations of small molecular weight analysts need to be quantified.

"Quantitative Detection of Dopamine" Example of sensogram (upper graph) Signal dependency on dopamine concentration (lower graph)

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AN114 Precisely characterizing molecular interactions kinetics without chemical labeling

Two experiments demonstrate that the SPR Navi 200 is a sensitive instrument for studies of biomolecular kinetics. It enables precise application of kinetic models including associa-tion and dissociation constants. The SPR Navi 200 is suitable for both large dynamic range and high sensitivity experiments. The open design of the SPR Navi 200 allows easy measurement on biochemical surfaces prepared outside the instrument, allowing efficient optimization of the surface chemistry of the sensor slide for biochemical studies.

"Biomolecular interaction kinetics measured using Surface Plasmon Resonance" A folic acid – folate binding protein injection with on-line referencing. The upper curve is the sample channel and the lower curve isthe reference channel.

AN116 Characterizing Graphene Films with BioNavis SPR Navi 200 and KSV-Nima PMI 550 before and after deposition with KSV-Nima Langmuir-Blodgett method

We introduced more thoroughly two powerful optical methods for characterizing graphene films before and after deposition, PM-IRRAS and SPR. With KSV-Nima PMI 550 it was possible to record detailed IR spectra of floating and deposited layers to determine the chemical composition. The SPR Navi 200 was capable of characterizing the thickness and the complex refractive indices of the deposited layers. It was possible to distinguish single sheet and aggregated graphene from each other.

"Deposition and Characterization of single-sheet graphene and graphene oxide films" SPR Spectra of Graphene films BG, GO1 and GO2. BG stands for Background and was measured from pure SPR sensor. The dashed lines are the fitted model curves from the experiments.

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AN121 Interactions of small molecular weight drug with human serum albumin

SPR Navi 200 is well suited to measure direct affinitiesof small molecules in physiologically meaningfulconcentration regimes. This type of measurements areimportant for pre-clinical drug screening, biochemicaldrug development and biochemical reaction studies,and we have demonstrated that SPR Navi 200 is anexcellent tool for this type of research.

"HSA-Quinidine interaction" Signal vs time plot (colored curves) for HSA-Quinidine interaction. Black lines are kinetic fit to the data.

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