Break‐up of Two‐Dimensional MnO₂ Nanosheets Promotes Ultrasensitive pH‐Triggered Theranostics of Cancer

Abstract

Chemically exfoliated two-dimensional MnO2 nanosheets are successfully modified with amino-polyethylene glycol as a theranostic platform for ultrasensitive stimuli-responsive theranostics of cancer. The highly dispersed MnO2 nanosheets exhibit a unique break-up in the mildly acidic microenvironment of tumor tissues, which could substantially enhance their in vitro and in vivo performances in T1 -weighted magnetic resonance imaging. Such a pH-triggered breaking-up behavior could further promote the fast release of loaded anticancer drugs for concurrent pH-responsive drug release and circumvent the multidrug resistance of cancer cells.

Magnetic nanoparticle-promoted droplet vaporization for in vivo stimuli-responsive cancer theranostics

“…33 The triggers can be intrinsic to the microenvironment, such as enzymes, a lowered pH value or elevated reducing conditions, [34][35][36] or external such as artificially introduced light, ultrasound or magnetic field. 37-43 Such an intelligent cancer treatment modality should release drug on-demand, improve diagnostic imaging or synergistic therapy.…”

Mesoporous carbon biomaterials

“…7b). Because the microenvironment of tumor tissue is more acidic than normal tissue [15,[57][58][59][60], this pH-responsive DOX-releasing profile facilitates tumor-localized drug release from HMCNs. Focused ultrasound could also break the π-π stacking to trigger the DOX release.…”

Manganese dioxide nanosheets-based redox/pH-responsive drug delivery system for cancer theranostic application

“…Interestingly, the release of CDDP from MnO 2 /HA/CDDP was apparently accelerated at pH 5.0 in comparison to that at pH 7.4 probably as a result of the weakening of the metal-carboxylate bond via protonation of the carboxylic groups of the HA unit ( Figure S2B) and the dissolution of MnO 2 in acid condition. 8,34 As expected, promoted drug release with a released percentage of 84.0% in the first 12 hours was obtained for MnO 2 /HA/CDDP nanosheets when they were placed in a reductive release medium supplemented with 2 mM GSH. The drug system could be decomposed due to the reduction in MnO 2 nanosheets by GSH, generating a great number of Mn 2+ ions.…”

“…4 Recently, its use for drug delivery system is reported for its relatively high drug-loading capacity and stimuli-responsive MRI property. Chen et al 8 found that the MnO 2 nanosheets with an average lateral size of ∼200 nm are superior nanocarriers for loading doxorubicin. Fan et al 9 suggested that DNAzyme could be efficiently transferred into cells by MnO 2 nanosheets.…”

“…8 However, its unstable property in saline and lack of tumor targeting limited its use for cancer drug delivery. HA, a polyanionic polysaccharide which consists of N-acetyl-d-glucosamine and β-glucuronic acid, has been widely used for tumor-targeting delivery, because it has high affinity toward CD44 (involved in cell-cell interactions, cell adhesion, and migration), which is overexpressed in many cancers.…”