Dual Functional Microcapsule based on Monodisperse Short PEG Amphiphile for Drug Encapsulation and Protein Affinity Controlled Release

Abstract

A short monodisperse poly(ethylene glycol) (PEG) and a neutral organic rotamer conjugate TEG‐BTA‐2 amphiphile was designed for the construction of a stimuli‐responsive switchable self‐assembled structure for drug encapsulation by noncovalent interaction and targeted controlled delivery. A short PEG, tetraethylene glycol (TEG) was covalently attached with a neutral organic rotamer benzothiazole dye (BTA‐2) affording the neutral TEG‐BTA‐2 (<500 D). The TEG‐BTA‐2 is self‐assembled into a microsphere in an aqueous medium, but remarkably undergoes morphology change switching to a rice‐like microcapsule for curcumin encapsulation. Curcumin‐loaded microcapsules were stable in an aqueous solution, however, were noticed disintegrating upon the addition of BSA protein. This is possibly due to an interaction with BSA protein leading to a protein affinity‐controlled curcumin release in a neutral PBS buffer. Moreover, cell internalization of the neutral amphiphile TEG‐BTA‐2 into A549 cells was observed by fluorescence microscopy, providing an opportunity for application as a molecular vehicle for targeted drug delivery and monitoring.