Charge conversional poly(amino acid)s derivatives as a drug delivery carrier in response to the tumor environment

Abstract

Charge-converting poly (amino acid)s derivative in response to acidic tumor environment was successfully derived. PHEA-g-C18 with a charge-converting property was designed by two significant steps, starting from polyaspartamide (PHEA) and including: (1) introduction of ethylenediamine groups via urethanic linkage; and (2) attachment of Dimethylmaleic acid (DMMA) in a basic condition. The obtained polymer had been verified to form a stable spherical micelle via TEM image, forming a well-defined structure, yet degrades well with the presence of proteolytic enzymes. The zeta potential value had converted from negatively-charged to positively-charged when it meets the acidic tumor extracellular environment. The results indicate that the charge conversion behavior would increase the cellular uptake, and moreover, decrease the unwanted protein adsorption under neutral condition. These proper-ties can further be applied as an early detecting module of cancer and become an advanced study of designing smart drug carriers for drug and gene delivery.