^99mTc-conjugated manganese-based mesoporous silica nanoparticles for SPECT, pH-responsive MRI and anti-cancer drug delivery

Abstract

In recent decades, hybrid imaging techniques that exploit the advantages of multiple imaging technologies have aroused extensive attention due to the deficiencies of single imaging modes. Along with the development of single photon emission computed tomography-magnetic resonance imaging (SPECT-MRI), it is currently necessary to develop a series of dual probes that can combine the outstanding sensitivity of SPECT with the high spatial resolution of MRI. Herein, the commonly used technetium-99 (Tc) was labelled on the surface of manganese oxide-based mesoporous silica nanoparticles (MnO-MSNs) for use in SPECT-MRI dual-modal imaging. The radiolabelling yield was as high as 99.1 ± 0.6%, and the r value of the nanoprobes was able to reach 6.60 mM s due to the pH-responsive properties of the MnO-MSNs. The high-performance SPECT-MRI dual-modal imaging was confirmed in vivo in tumour-bearing mice, which could also provide semi-quantitative information for tumour detection. Importantly, these nanoprobes can deliver anti-cancer drugs in cancer therapy due to their unique mesoporous structures. Thus, nanotheranostics combining dual-modal imaging with anti-cancer therapeutic properties were achieved.

Manganese Oxide Nanomaterials: Synthesis, Properties, and Theranostic Applications

“…99m Tc‐conjugated MnO x ‐MSNs for single photon emission computed tomography (SPECT) imaging. Reproduced with permission . Copyright 2016, Royal Society of Chemistry.…”

Protoporphyrin‐IX and Manganese Oxide Nanoparticles Encapsulated in Niosomes as Theranostic

“…Early diagnosis and treatment of cancer, as well as the application of therapy at the appropriate dose and to the target area, are very crucial. MnO NPs and protoporphyrin combinations into the nanovesicules are promising nano materials due to their biocompatibility, lower toxicity and enhanced contrast properties in MR imaging which provides a great advantage in imaging with a positive contrast enhancement …”

Recent Progress on Manganese‐Based Nanostructures as Responsive MRI Contrast Agents

“…Severald ifferent substrates have been proposed as "reducing" agentsf or permanganate, from classic reducing agents such as sodium borohydrate (NaBH 4 ), [50] to green alternatives already described for other nanotechnology applications( e.g.,g lucose), [51,52] to polymers with reducing properties (PAH, poly allylamine hydrochloride, [32,53] polyvinylpyrrolidonep lus polyacrylic acid (PAA) [31] )o rt ob iological/biochemicalm olecules (proteins such as bovine serum albumin (BSA), [54] or buffers like 2-(N-morpholino)ethanesulfonic acid (MES)). [55] Anothers trategy,f ollowedp articularly when the objective is to grow MnO 2 on top of another structure, is to use unreacted/partially reacted materials from previouss teps of the synthesis, to reduce KMnO 4 .F ollowing this strategy,M nO 2 has been grown on top of SiO 2 nanoparticles (or SiO 2 shells)b y using partially reacted silaneso nt he surface of the nanoparticles (Figure2E), [45,[56][57][58][59] and MnO 2 nanosheets were grown on gold nanostars by using unreacted HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) from the preparation of the nanostars. [60] Similarly,n anostructures with redox properties can also be used to reduce the permanganate precursor to MnO x nanostructures.…”