Facile dynamic one-step modular assembly based on boronic acid-diol for construction of a micellar drug delivery system

Nano-assembled amphiphilic micelles with characteristics including facile control, a simplified construction procedure, convenient and efficient drug loading, and a controlled release at pathological sites are in high demand. This study reports a facile and dynamic one-step modular assembly strategy based on boronic acid-diol for constructing focus-responsive micellar drug delivery systems. In this manner, a dopamine modified hydrophilic building block, phenylboronic acid modified hydrophobic building block and drug molecules (Dox) spontaneously one-step assembled into drug encapsulated distinct core/shell micelles (Dox/PBAE-M) in mild physiological media. After a simple adjustment of weight ratios between these three building blocks, Dox/PBAE-M, with the highest Dox-loading capacity (22.4%) and optimal physical dimensions, was generated. Furthermore, the desirable pH-dependent disassembly of Dox/PBAE-M was independently verified by morphological changes alongside in vitro release of Dox in different simulated environments. The experimental results here demonstrated that Dox/PBAE-M kept structural integrity in normal physiological environments, while accomplishing a selective nano-disassembly and Dox release within acid endo/lysosomes. As a result, Dox/PBAE-M exhibited the highest cytotoxicity and apoptosis induction among all of the tested groups on the 4T1 breast cancer xenograft model. This newly proposed assembly strategy gave new insight into easy fabrication and disassembly of multi-functional micellar drug delivery systems.