OWLS Sensors - Label free biosensors

Category Archives: Application Notes

OWLS Biosensors in Pharmaceutical Research

OWLS 210 real-time, label-free biosensor systemAMGEN researchers published their first results using OWLS 210 for studying Poloxamer/ Polysorbate adsorption. Their resarch was published in April 2014 in the Journal of Pharmaceutical Sciences.


Modulation of Protein Adsorption by Poloxamer 188 in Relation to Polysorbates 80 and 20 at Solid Surfaces
Journal of Pharmaceutical Sciences,
Volume 103, Issue 4, pages 1043–1049, April 2014


Poloxamer 188 (BASF Pluronic® F68) is widely used as a shear-protective excipient to enhance cell yield in agitated cultures and reduce cell adhesion in stationary cultures. However, little is known in any quantitative sense of its effect on protein adsorption and aggregation. Optical waveguide lightmode spectroscopy was used here to compare the adsorption kinetics exhibited by poloxamer 188, and polysorbates 80 and 20, in the presence and absence of a model protein (chicken egg white lysozyme) and in separate experiments, a recombinant protein (human granulocyte colony-stimulating factor) at hydrophilic, silica–titania surfaces. Experiments were performed in sequential and competitive adsorption modes, enabling the adsorption kinetic patterns to be interpreted in a fashion revealing the dominant mode of surfactant-mediated stabilization of protein in each case. Kinetic results showed that polysorbates 80 and 20 are able to inhibit protein adsorption only by their preferential location at an interface to which they show sufficient affinity, and not by formation of less surface active, protein–surfactant complexes. On the other hand, poloxamer 188 is able to inhibit protein adsorption by entering into formation of protein–surfactant complexes of low adsorption affinity (i.e., high colloidal stability), and not by its preferential location at the interface. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:1043–1049, 2014

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Detecting Cell Physiological Changes in Response to Light Induced Ion Channel Opening

Abstract Light-gated ion channels allow modifying transmembrane ion fluxes and consequently,the intracellular distribution of ions without applying electric fields or introducing stimulating electrodes. Channelrhodopsyn is a Na+ and Ca2+ permeable cation channel, which opens in response to illumination at wavelengths of 460-490 nm. The influx of Na+ and Ca2+ depolarizes the cells and results inContinue Reading

Optical Anisotropy of Flagellin Layers

Abstract Polymeric flagellin consists of four linearly connected domains labeled D0, D1, D2, and D3, which are arranged from the inside to the outside of the filament. The disordered terminal regions are involved in D0 and partly in D1, forming long helical bundles, and their direct interaction is responsible for stabilizing the filament structure.A centralContinue Reading

Label-free immunosensor for Aflatoxin B1

Abstract Aflatoxins are toxic metabolites produced by Aspergillus species (mainly A. Flavus, A. parasiticus,and A. nomius) and can be present in a wide range of food and feed commodities. Because of thepersistence of Aflatoxins in the food chain, exposure to the compound is a potential human healthhazard. This has prompted adoption of regulatory limits inContinue Reading

Label-free immunosensor for herbicide trifluralin detection with OWLS

Abstract Acting as a potent microtubule inhibitor, the dinitroaniline herbicide trifluralin has been used in agricultural applications as a selective, pre-emergence herbicide in various plant cultures including grain, crops, vegetables, fruits and nuts. In recent years, the compound is a subject to increasing toxicological and environmental concerns. OWLS offered a highly sensitive label free methodContinue Reading

Label-free immunosensor for HSP70 detection

Abstract OWLS immunosensor offers a real time label-free detection of heat shock protein, HSP70 (molecular weight of70 kDA). For biosensing monoclonal antibodies raised against HSP70 protein under investigation were used. Toform regenerable sensor surface, the waveguide sensor surface was modified with amino group and sensitized byimmobilizing antibody/antigen molecules covalently to the surface. Label-free immunosensor forContinue Reading

Determination of TNFa concentration in human serum

Abstract Immunosensors were constructed for rapid and label-free determination of TNFα concentrations in human serum samples Download the full application note

Test measurement of label-free immunosensor using BSA-antiBSA model molecule pair (GA)

In the case of glass type metal oxide surfaces suchas SiO2-TiO2, mainly hydroxyl groups are present, which offer relatively few possibilities for covalent immobilization of biomolecules. To widen the circle of covalent coupling methods, the surface of the waveguide has to be modified by silanization using reactive silane reagents for introducing functionalgroups of all sortsContinue Reading