Micro-competition system for Raman quantification of multiple glycans on intact cell surface† †Electronic supplementary information (ESI) available: Experimental details and supplementary figures. See DOI: 10.1039/c5sc01031d Click here for additional data file.

A micro-competition system is designed for simultaneous quantification of multiple glycans on intact cell surfaces, by integrating two-surface–one-molecule competition with surface enhanced Raman scattering (SERS). The micro-competition is achieved among multiple-polysaccharide-coated gold nanostars functionalized silica bubbles, target cells and gold nanoprobes at a micron scale. The gold nanoprobes are prepared by coating distinct Raman molecules and lectins on gold nanoparticles for signal resolution and glycan recognition, respectively. The silica bubble surface serves as an artificial glycan surface and a SERS substrate. Upon the competitive recognition of lectin to the corresponding glycan, the gold nanoprobes can be specifically captured by the bubbles and cells in a homogeneous system, and the amounts of different gold nanoprobes on bubbles are simultaneously detected by SERS to reflect the corresponding glycan amounts on the cell surface. This micro-competition system with multiple quantification capability provides a powerful tool for investigation of the complex glycan-related biological processes.