Organogels based on self-assembly of diphenylalanine peptide and their application to immobilize quantum dots

We report that a single dipeptide (L-Phe-L-Phe, FF), which is probably one of the smallest peptide gelators. can self-assemble into long nanofibrils in organic solvents and entangle further to form gels. The obtained FF gels are responsive to temperature, and the FF sol-gel process is thermoreversible. The formation of such gels may be driven by the hydrogen bond of peptide main chains and the pi-pi interactions between aromatic residues of the peptide. Lipophilic nanocrystals can be encapsulated into the gel through gelating the organic solution of corresponding nanocrystals using the FF gelator at room temperature. Quantum dots (QDs) are encapsulated into the FF gel by adopting the above method. The resulting gels with the incorporated QDs still remain photoluminescent (PL). It is an effective method to protect QDs from oxidation and improve the stability of the QDs. This strategy is generally suited for encapsulation of lipophilic nanocrystals.