Gold nanorods/polydopamine-capped hollow hydroxyapatite microcapsules as remotely controllable multifunctional drug delivery platform

Abstract In the present paper, hollow hydroxyapatite/polydopamine/gold nanorods (H-HAP/PDA/AuNRs) hybrid microcapsules was prepared for multi-responsive drug delivery via self-assembly method. PDA/AuNRs hybrid shell was employed to obstruct the initial burst drug release and endow the hybrid vehicle with superior photothermal conversion capacity, robust photothermal stability and brilliant near-infrared (NIR)-responsive delivery property. Moreover, due to the mesoporous structure of H-HAP as well as the strong mutual adsorption between PDA and drug, H-HAP/PDA/AuNRs exhibited excellent drug loading efficiency (95.6%). The drug release results demonstrated that the hybrid vehicle possessed distinct pH-/NIR- dual responsiveness, which due to the disintegration of HAP/PDA matrix in acid condition and the synergistically enhanced NIR responsiveness of PDA/AuNRs. Furthermore, cell viability results demonstrated that H-HAP/PDA/AuNRs exhibited outstanding biocompatibility and low bio-toxicity. Thus, the as-prepared H-HAP/PDA/AuNRs hybrid microcapsules hold great promise as novel smart drug carriers for remotely controllable drug delivery.