Surface Plasmon Resonance Imaging (SPRi) for Glycoprotein Profiling

The presence of several parallel microchannels on the same sensing surface in the surface plasmon resonance imaging (SPRi) system allows in-line referencing in order to control possible non-specific binding. SPRi technique provides sensitive and fast imaging of tens and even hundreds of bio interactions simultaneously within one small-sized array. SPRi has been widely used in the measurement of real-time kinetic and affinity parameters of the carbohydrate-protein interaction. Equipped with state-of-the-art technologies and top-class scientific experts in applying SPRi for glycoprotein profiling, Creative Biolabs is confident in providing top-quality service to facilitate our clients’ glycoprotein related project development.

Background of SPRi

The SPR sensor is a widely used tool for the study of binding kinetics between biomolecular species. SPR is featured with lots of advantages including its real-time and label-free sensing capabilities. In high-throughput screening (HTS) analyses, a combination of protein arrays and the SPR technique would provide an excellent alternative. However, standard SPR biosensor instrumentations are based on single- or several-channel configurations. With the emergence of drug screening and investigation of biomolecular interactions on a large scale, there is a growing demand for HTS method. Therefore, SPRi has been explored intensively in recent years to simultaneously process hundreds or thousands of samples.

Principle of SPRi

Using rapid optical arrays, SPRi systems have potential applications in the HTS of drugs and biomarkers, as well as clinical diagnosis through multi-arrays. Except for the sensitive label-free method, the additional value of SPRi lies in its ability to visualize a whole biochip via a charge-coupled device (CCD) camera. This improved property enables biochips to be prepared in an array format, in which each array spot can provide a great deal of SPR information simultaneously. A coherent polarized light beam is used instead of polychromatic light in an SPRi system. This change helps expand the light cover on a larger area of the sensing surface. The reflected light is captured by a CCD camera for further imaging analysis. The high-resolution CCD camera provides images in a real-time manner with up to hundreds of active spots. Captured images can provide detailed information on molecular binding, interactions or kinetic processes. Unlike conventional SPR, SPRi is stringently performed at a constant wavelength and a constant angle. Thus, changes in reflected light intensity are proportional to any variation of the refractive index near the metal surface.

Fig.1 General principle of SPRi. (Nguyen, 2015)

Applications of SPRi in the Study of Glycoprotein

In the previous study, SPRi has been used to differentiate glycoproteins and non-glycoproteins. Glycoproteins were used as model components while non-glycoproteins were used as controls. The samples were precisely deposited on the thiolised gold dots using a microprinting pin and let covalently bind to the modified surface. Then the immobilized molecules were allowed to react with lectin and the produced resonance image signals were recorded by CCD camera. It was shown that glycoproteins produce higher signals after interaction with lection than non-glycoproteins. Moreover, the signal from glycoprotein with more mannose residues was stronger than the one glycoprotein with less. In the SPRi system, the small area of the printed protein spots allows creating the larger proteins array to increase the number of potential analytes. Hence, SPRi is a powerful tool for both high throughput label-free screening and sensitive analysis of not only glycoproteins, but also other glycoforms.

SPRi for Glycoprotein Profiling at Creative Biolabs

SPRi technology allows the measurement of hundreds of samples at a time with using a microarray immobilized on the gold surface, and allows easy referencing with negative controls in order to check the non-specific adsorption. This makes it possible to be applied for fast and inexpensive screening of biological samples for the identification of tumor biomarkers, not only glycoproteins but also diverse glycoforms, such as glycoconjugates. Glycans and their conjugates with proteins and lipids contribute significantly to many biological processes, making these compounds important targets to be detected, monitored and identified. SPRi can be greatly useful in the study of glycans and their conjugates.

With substantial experience and expertise in SPRi for glycoprotein profiling, Creative Biolabs offers high-quality services including but not limited to:

Study the carbohydrate-specific interactions
Fast screening of glycoconjugates
Monitoring of the carbohydrate-specific bindings
Identify glycoproteins from a complex sample
Serum glyco-profiling

Highlights

Label-free interaction analysis
Real-time monitoring of kinetic and affinity parameters
Measurement of hundreds of samples at a time
Temperature control: 4°C-40°C

SPRi system is increasingly employed for investigation of binding affinities, kinetic parameters, biospecific interactions, and real-time quantitative measurements in the field of glycomics. Creative Biolabs is dedicated to serving every unique need of our clients in applying SPRi for glycoprotein profiling by providing custom experiment design and affinity measurement services. For more detailed information, please feel free to contact us or directly send us an inquiry.

Reference

Nguyen, H.H.; et al. Surface plasmon resonance: a versatile technique for biosensor applications. Sensors. 2015, 15(5):10481-510.

For Research Use Only.