Small Molecule Microarrays

Yi Chen, Chanjuan Liu, Xiao Wang

Mahesh Uttamchandani, Shao Q. Yao

Microarray-based saccharide chips possess an inherent property of high throughput but remain hard to use in practice due mainly to their fabrication problems, which have led to many strategies proposed but nearly none can immobilize small saccharides without losing their bio-affinity. Herein introduced is an easy strategy able to directly immobilize all intact saccharides on solid surface with excellent preservation of their molecular recognition ability. The core idea is to anchor a saccharide molecule on a universally rotatable molecular frame to free its spatial adjustment during molecular recognition process. This strategy can simply be realized by use of cyanuric chloride as a rotatable linker which offers three reactive chlorines pointing at 120°. The first chlorine can readily react with hydroxyl groups at only 0-5 °C, enabling one to "plant" a layer of Y-shaped rotatable linker on hydroxyl-terminated surfaces. This facilitates the second chlorine on one of the upper "Y-branch" to react with saccharides at ca. 25 °C, a very convenient room temperature for practical manipulation. The third chlorine can further react with saccharides but at ca. 50 °C which is not too difficult to manipulate but commonly is not utilized. This chemical strategy has been exploited to dot various intact hydroxyl substances on either gold or glass surfaces, and the recognition ability of the anchored saccharides with their right lectins was validated to be well preserved according to surface plasmon resonance and/or laser-induced fluorescence imaging data. Furthermore the method is extendable to amines and other substances able to be hydroxylated and/or aminated.