Compared with carbon-chain polymers, poly(amino acid)s have attracted much attentions in biomedical and pharmaceutical fields because of their good biocompatibility, biodegradability and nontoxicity. Polyaspartamide derivatives based on L-aspartic acid not only can be easily synthesized, but also can be further modified with various structures to prepare intelligent material with different stimuli-responsivity (such as temperature, pH and redox), resulting in controlled release, enhancement of therapeutic effects and reduction of the drug side effects. In this review, the different synthetic strategies for preparing polyaspartamide derivatives and the up-to-date developments on polyaspartamide derivatives for drug and gene delivery systems are summarized. Besides, the future perspectives of polyaspartamide derivatives are discussed.

Contents
1 Introduction
2 Synthesis of polyaspartamide derivatives
2.1 Aminolysis reaction of PSI
2.2 ROP of N-carboxyanhydride
3 Application of polyaspartamide derivatives
3.1 Drug delivery
3.2 Gene delivery
4 Outlook