NIR‐II Responsive Hollow Magnetite Nanoclusters for Targeted Magnetic Resonance Imaging‐Guided Photothermal/Chemo‐Therapy and Chemodynamic Therapy

Abstract

Phototherapy in the second near‐IR (1000–1700 nm, NIR‐II) window has achieved much progress because of its high efficiency and relatively minor side effects. In this paper, a new NIR‐II responsive hollow magnetite nanocluster (HMNC) for targeted and imaging‐guided cancer therapy is reported. The HMNC not only provides a hollow cavity for drug loading but also serves as a contrast agent for tumor‐targeted magnetic resonance imaging. The acid‐induced dissolution of the HMNCs can trigger a pH‐responsive drug release for chemotherapy and catalyze the hydroxyl radical (·OH) formation from the decomposition of hydrogen peroxide for chemodynamic therapy. Moreover, the HMNCs can adsorb and convert NIR‐II light into local heat (photothermal conversion efficacy: 36.3%), which can accelerate drug release and enhance the synergistic effect of chemo‐photothermal therapy. The HMNCs show great potential as a versatile nanoplatform for targeted imaging‐guided trimodal cancer therapy.

Iron-Based Hollow Nanoplatforms for Cancer Imaging and Theranostics

“…Of note, doxorubicin (DOX) is most widely explored among the reported model drugs. Recently, Wang et al [ 106 ] constructed a novel hollow magnetite nanocluster (HMNC) to load DOX for MRI-guided NIR-II PTT/CDT/chemotherapy ( Figure 5 A). As shown in Figure 5 B,C, the as-prepared HMNC was composed of ~38.8 nm nanocrystals, displaying a hollow spherical shape with an average particle size of 215 ± 20 nm and pore size of 3.68 nm, respectively.…”

Activatable Second Near-Infrared Fluorescent Probes: A New Accurate Diagnosis Strategy for Diseases

“…The rapid proliferation of tumor cells leads to the characteristic changes in energy metabolism [ 58 , 59 ]. Tumor cells are vigorous with respect to energy metabolism, consuming large amounts of glucose and converting it to lactate, resulting in an increase in extracellular H + concentration and a decrease in pH value [ 18 , 60 , 61 ]. Inorganic NIR-II fluorescent probes have a high degree of stability, which can be controlled by modifying the pH-responsive groups on their surfaces.…”

Recent advances in near-infrared-II hollow nanoplatforms for photothermal-based cancer treatment

“…A promising way is to incorporate these diagnostic and therapeutic functions into one single nanoplatform especially hollow nanoplatform [ 69 – 71 ]. Hollow nanoplatforms are accompanied by mesoporous pore structures, thus it is not uncommon to see small molecule drugs encapsulated into the cavities [ 72 , 73 ]. Such novel nanoplatforms are able to serve as smart drug delivery systems (DDSs) to enhance the therapeutic outcomes of conventional chemotherapy and radiotherapy with reduced side effects [ 74 , 75 ].…”

“…In general, the synthetic strategies for hollow nanoplatforms are divided into sacrificial-template-based method and self-templating method, the details of which will be discussed in the next section. Notably, the hollow nanoplatforms alone can be good PTAs or serve as the substrates to support the deposition of PTAs [ 72 , 79 ]. With other functional components combined, the hollow structured nanoplatforms are expected to allow imaging-guided PTT-based treatments.…”