Multifunctional hollow mesoporous silica nanospheres for imaging and targeting drug delivery

The flexible modification of hollow mesoporous silica nanospheres (HMNs) provides a great opportunity to construct a new generation of multifunctional nanocarriers. In this study, we developed a novel HMNs-based drug delivery system, HA@GHMNs, which is composed of gadolinium-doped hollow mesoporous silica nanospheres (GHMNs) and the targeting molecule hyaluronic acid (HA). A series of physicochemical characterizations, including size, morphology, drug loading capacity, and magnetic properties, confirmed the successful preparation of HA@GHMNs. HA@GHMNs loaded with paclitaxel (PTX), termed HA@GHMNs-PTX, exhibited remarkable antitumor activity. Compared to GHMNs carriers, HA@GHMNs showed negligible toxicity and significantly enhanced cellular uptake in 4T1 cells. Moreover, HA@GHMNs demonstrated a high relaxivity of 16.48 mM^-1s^-1, which is four times higher than that of clinical gadolinium chelates. In vivo experiments further confirmed that HA@GHMNs-PTX effectively inhibited tumor growth and enabled magnetic resonance imaging (MRI) visualization of the tumor site. Overall, HA@GHMNs-PTX shows great potential as an efficient theranostic nanoplatform for tumor treatment and MRI.