Smart nanoparticles with a detachable outer shell for maximized synergistic antitumor efficacy of therapeutics with varying physicochemical properties.

Co-delivery systems capable of transporting hydrophobic chemotherapeutics and hydrophilic siRNA to the same cell population with simultaneous burst release of both drugs to maximize synergistic anticancer efficacy remains elusive. In this light, a multifunctional nanoparticle (HA-PSR) consisting of a redox-sensitive core and detachable crosslinked hyaluronic acid (HA) shell was developed. Octyl modified PEI containing disulfide linkages (PSR) were synthesized as the core materials for co-encapsulation of chemotherapeutics and siRNA, while a HAase-sensitive thiolated HA (HA-SH) was collaboratively assembled to the anionic shell for CD44-mediated active targeting along with enhanced and detachable protection for drug loaded inner cores. Resultantly, HA de-protected redox-sensitive inner cores achieved co-burst release of both cargoes when triggered by glutathione (GSH) rich environments in cytoplasm. Results of in-vivo and in-vitro testing indicated successful co-encapsulation of hydrophobic drugs and hydrophilic siRNA with adjustable ratios. Selective delivery to CD44 overexpressing tumors was achieved through passive and active targeting, followed by HAase-triggered HA de-shielding and GSH-triggered burst release of both cargos. Rapid intracellular trafficking maximized synergistic cytotoxicities of chemotherapeutics and siRNA for remarkable tumor inhibition in a xenograft animal tumor model. Consequently, the HA-PSR nanoparticle holds great potential for combined chemotherapeutics/siRNA treatment in cancer with maximized synergistic antitumor efficacy.