Nanoparticle-based drug delivery system with enhanced loading and targeting performance: A brief account

For the construction of a nanoparticle (NP)-supported drug delivery system (DDS), loading efficiency, stable encapsulation, and targeted delivery are considered crucial to achieve a high therapeutic outcome of the resulting system. Conventionally, NPs are functionalized with desired molecules via covalent interactions, which do not only limit the intraparticle space for drug loading but also cause significant loss of the preloaded drug through the multistep chemical reactions. Furthermore, NPs with covalently modified surface are easily surrounded with biomolecules during blood circulation, and their accumulation in a target site becomes considerably hampered. Keeping these issues in mind, we herein summarize the recently reported unconventional strategies to prepare a more powerful DDS with enhanced loading and targeting ability, by installing a noncovalent polymeric gatekeeper or surface-protective biomolecular layer on the NP surface.