The ProteOn XPR36™ Array System—High Throughput Kinetic Binding Analysis of Biomolecular Interactions

Sensitive and label-free SPR biosensing platforms for high-throughput screening of plasma membrane receptors interactions with insulin-like targets of hypoglycaemic activity

Progress in medical sciences aims for tailored therapy of civilization diseases like diabetes. Preclinical screening of new medicines superior to insulin should include the verification of their affinity to the membrane receptors naturally stimulated by this hormone: insulin receptor isoforms A and B and insulin-like growth factor receptor. Considering that the affinity constants obtained using different experimental conditions are incomparable, it is essential to develop a robust and reliable method to analyze these interactions. The versatile SPR platform developed in this study enables the evaluation of the bioactivity of hypoglycaemic molecules. Thanks to the comprehensive characterization of miscellaneous aspects of the analytical platform, including the design of the SPR biosensor receptor layer, ensuring interaction specificity, as well as the quality control of the standards used (human insulin, HI; long-acting insulin analog: glargine, Gla), the feasibility of the method of equilibrium and kinetic constants determination for insulin-like targets was confirmed. SPR assays constructed in the direct format using IR-A, IR-B, and IGF1-R receptor proteins show high sensitivities and low detection limits towards insulin and glargine detection in the range of 18.3-53.3 nM with no signs of mass transport limitations. The improved analytical performance and stability of SPR biosensors favor the acquisition of good-quality kinetic data, while preservation of receptors activity after binding to long-chain carboxymethyldextran, combined with spontaneous regeneration, results in stability and long shelf life of the biosensor, which makes it useful for label-free insulin analogs biosensing and thus extensive screening in diabetic drugs discovery.

On the Use of Surface Plasmon Resonance-Based Biosensors for Advanced Bioprocess Monitoring

Biomanufacturers are being incited by regulatory agencies to transition from a quality by testing framework, where they extensively test their product after their production, to more of a quality by design or even quality by control framework. This requires powerful analytical tools and sensors enabling measurements of key process variables and/or product quality attributes during production, preferably in an online manner. As such, the demand for monitoring technologies is rapidly growing. In this context, we believe surface plasmon resonance (SPR)-based biosensors can play a role in enabling the development of improved bioprocess monitoring and control strategies. The SPR technique has been profusely used to probe the binding behavior of a solution species with a sensor surface-immobilized partner in an investigative context, but its ability to detect binding in real-time and without a label has been exploited for monitoring purposes and is promising for the near future. In this review, we examine applications of SPR that are or could be related to bioprocess monitoring in three spheres: biotherapeutics production monitoring, vaccine monitoring, and bacteria and contaminant detection. These applications mainly exploit SPR’s ability to measure solution species concentrations, but performing kinetic analyses is also possible and could prove useful for product quality assessments. We follow with a discussion on the limitations of SPR in a monitoring role and how recent advances in hardware and SPR response modeling could counter them. Mainly, throughput limitations can be addressed by multi-detection spot instruments, and nonspecific binding effects can be alleviated by new antifouling materials. A plethora of methods are available for cell growth and metabolism monitoring, but product monitoring is performed mainly a posteriori. SPR-based biosensors exhibit potential as product monitoring tools from early production to the end of downstream processing, paving the way for more efficient production control. However, more work needs to be done to facilitate or eliminate the need for sample preprocessing and to optimize the experimental protocols.

Dataset of the binding kinetic rate constants of anti-PCSK9 antibodies obtained using the Biacore T100, ProteOn XPR36, Octet RED384, and IBIS MX96 biosensor platforms

Here we provide data from a head-to-head comparison study using four biosensor platforms: GE Healthcare׳s Biacore T100, Bio-Rad׳s ProteOn XPR36, ForteBio׳s Octet RED384, and Wasatch Microfluidics׳s IBIS MX96. We used these instruments to analyze the binding interactions of a panel of ten high-affinity monoclonal antibodies with their antigen, human proprotein convertase subtilisin kexin type 9 (PCSK9). For each instrument, binding curves obtained at multiple densities of surface antibodies were fit to the 1:1 Langmuir kinetic model, and the association and dissociation rate constants and corresponding affinity constants were calculated. The data supplied in this article accompany the research article entitled, “Comparison of biosensor platforms in the evaluation of high affinity antibody–antigen binding kinetics” (Yang et al., 2016) [1], which further discusses the strengths and weaknesses of each biosensor platform with an emphasis on data consistency, comparability, and operational efficiency.

Therapeutic antibodies: Discovery and development using the ProteOn XPR36 biosensor interaction array system

Therapeutic monoclonal antibodies are becoming a significant and rapidly growing class of therapeutic pharmaceuticals. Their discovery and development requires fast and high-throughput methodologies for screening and selecting appropriate candidate antibodies having high affinity for the target as well as high specificity and low cross-reactivity. This study demonstrates the use of the ProteOn XPR36 protein interaction array system and its novel approach, termed One-Shot Kinetics, for the rapid screening and selection of high-affinity antibodies. This approach allows multiple quantitative protein binding analyses in parallel, providing association, dissociation, and affinity constants for several antibodies or supernatants simultaneously in one experiment. We show that the ProteOn XPR36 system is a valuable tool for use across multiple stages of the therapeutic antibody discovery and development process, enabling efficient and rapid screening after panning, affinity maturation, assay validation, and clone selection.

Grading the commercial optical biosensor literature-Class of 2008: 'The Mighty Binders'

Optical biosensor technology continues to be the method of choice for label-free, real-time interaction analysis. But when it comes to improving the quality of the biosensor literature, education should be fundamental. Of the 1413 articles published in 2008, less than 30% would pass the requirements for high-school chemistry. To teach by example, we spotlight 10 papers that illustrate how to implement the technology properly. Then we grade every paper published in 2008 on a scale from A to F and outline what features make a biosensor article fabulous, middling or abysmal. To help improve the quality of published data, we focus on a few experimental, analysis and presentation mistakes that are alarmingly common. With the literature as a guide, we want to ensure that no user is left behind.