β-Ga2O3:Cr3+ nanoparticle: A new platform with near infrared photoluminescence for drug targeting delivery and bio-imaging simultaneously

Synthesis of nanoparticles and cellular uptake: Three different sizes of β-Ga2O3:Cr3+ were synthesized and were used as drug carriers. After coating by l-Cys modified hyaluronic acid, they could internalize in cancer cell via CD44 receptor-mediated endocytosis, and near infrared fluorescence was showed under exciting light, which could be used for bio-imaging. [Display omitted] Multifunctional nanoparticles which integrate the therapeutic agents and bio-imaging agents into one carrier are emerging as a promising therapeutic platform. Herein, GaOOH:Cr3+ was firstly synthesized using improved hydrothermal method (atmospheric pressure, 95°C), and by manipulating the pH of the reaction medium, GaOOH:Cr3+ with different sizes (125.70nm, 200.60nm and 313.90nm) were synthesized. Then β-Ga2O3:Cr3+ nanoparticles with porous structures were developed as a result of the calcination of GaOOH:Cr3+. The fabricated, porous β-Ga2O3:Cr3+ nanoparticles could effectively absorb doxorubicin hydrochloride (DOX) (loading rate: 8% approximately) and had near infrared photoluminescence with a 695nm emission. Furthermore, β-Ga2O3:Cr3+ nanoparticles were coated with l-Cys modified hyaluronic acid (HA-Cys) by exploiting the electrostatic interaction and the cross-link effect of disulfide bond to improve the stability. The DOX loaded HA-Cys coated β-Ga2O3:Cr3+ nanoparticles (HA/β-Ga2O3:Cr3+/DOX) showed an oxidation–reduction sensitive drug release behavior. The HA-Cys coated β-Ga2O3:Cr3+ nanoparticles showed a low cytotoxicity on MCF-7 and Hela cell lines. The cellular uptake of HA/β-Ga2O3:Cr3+/DOX using the near infrared photoluminescence of β-Ga2O3:Cr3+ nanoparticles and the fluorescence of DOX demonstrated the HA/β-Ga2O3:Cr3+/DOX could internalize into tumor cells quickly, which was affected by the size and shape of β-Ga2O3:Cr3+nanoparticles.