Universal screening platform using three-dimensional small molecule microarray based on surface plasmon resonance imaging

Although much progress has been made in the field of small molecule microarrays in the past decades, its potential has been limited by a lack of efficient methodology. Herein we report a potent methodology for drug screening on a three-dimensional (3D) surface using a carbene based photo-cross-linking reaction. The simultaneous display of a large number of small molecules on a single polymer chain in various orientations allows for the retention of their activity. The presented method was tested using high throughput surface plasmon resonance (SPRi) with the immunosuppressive drugs rapamycin and FK506. We showed that rapamycin and FK506 immobilized on the 3D surface, not the conventional 2D surface, bound to the FKBP with high affinity. Using FKBP-binding ligands and FKBP mutants with altered mutual binding affinities, we observed a strong correlation between the relative binding affinities determined by SPRi and those previously reported. In addition, other important parameters including blocking, washing, robustness and surface reproducibility were also validated. Some well known kinase inhibitors of p38α, JNK and EKR2 proteins were also used to extend the applications of the method. All together, these results suggested that the newly developed 3D small molecule microarray in conjunction with SPRi can be a powerful platform for high throughput drug screening.