Self-Assembly of Peptide-Conjugated Forklike Mesogens at Aqueous/Liquid Crystalline Interfaces: Molecular Design for Ordering Transition Induced by Specific Binding of Biomolecules

Self-assembly of functional liquid crystals provides a powerful approach to the development of stimuli-responsive materials and interfaces. Here, we have designed and synthesized bioconjugated amphiphilic dendritic mesogens containing arginine-glycine-aspartic acid (RGD) peptide sequence to develop new biofunctional aqueous/liquid crystalline interfaces. We have found that the RGD peptide-conjugated forklike mesogens induce the homeotropic alignment of liquid crystals at the aqueous interfaces, leading to distinct optical changes caused by the specific binding of the target proteins. In contrast, no response to the target protein is observed for the interfaces prepared with the RGD peptide-conjugated single mesogen. Molecular insights into the orientation and stimuli-responsiveness of the bioconjugated mesogens at the interfaces are obtained based on measurements of the Langmuir films and self-assembled properties of these molecules. These results demonstrate that the number of rodlike cores of the bioconjugated mesogens affects the monolayer structures formed at the aqueous interface as well as the liquid crystalline properties. We propose a new molecular design of bioconjugated mesogens to couple biomolecular interactions at the aqueous interfaces with the ordering transition of the liquid crystals. These materials have the potential to tailor the responsiveness of liquid crystalline interfaces for biomolecular sensing.