A Hybrid Silica Nanoreactor Framework for Encapsulation of Hollow Manganese Oxide Nanoparticles of Superior T1 Magnetic Resonance Relaxivity. (24th July 2015)

• Record Type: Journal Article
• Authors: Hsu, Benedict You Wei; Ng, Michael; Zhang, Yu; Wong, Siew Yee; Bhakoo, Kishore; Li, Xu; Wang, John
• Is Part Of: Advanced functional materials. Volume 25:Number 33(2015)
• Page Start: 5269
• Page End: 5276
• Publication Date: 2015-07-24
• Subjects: hollow nanoparticles -- magnetic resonance imaging -- nanoreactors -- contrast agents; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201501269
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract : A new hybrid nanoreactor framework with poly(ethylene oxide)‐perforated silica walls is designed to encapsulate hollow manganese oxide nanoparticles (MONs) of high distinctness and homogeneity. Achieved by an interfacial templating scheme, the nanoreactor ensures that acidic etching of MONs by an acetate buffer solution is highly controlled for precise control of the hollow interior. As such, hollow MONs with different nanostructures are developed successfully through a facile acetate buffer solution etching. The resultant hollow MONs are integrated within the hybrid nanoreactor and demonstrate superior r 1 relativity of up to 2.58 mm −1 s −1 for T1 magnetic resonance imaging (MRI). By modifying the nanoreactor architecture, it is also demonstrated that the efficacy of MONs as T1 MRI contrast agents can be significantly improved if an optimal cluster of hollow MONs is encapsulated into the hybrid silica framework. The evolution of core morphology with time is studied to elucidate the etching mechanism. It is revealed that the hollow formation arises due to the surface stabilization of MONs by acetate ions and the subsequent acidic etching of the interior core in a sporadic manner. This is different from the commonly reported nanoscale Kirkendall effect or the selective etching of the core–shell MnO/Mn3 O4 structure. Abstract : A hybrid silica nanoreactor is designed for preparing hollow manganese oxide nanoparticles (MONs) under highly controlled conditions. Well‐defined hollow MONs exhibit high r 1 relativity of up to 2.58 mm −1 s −1 when multiple MONs are encapsulated within the framework. The formation of hollow MONs is due to surface stabilization by acetate ions, followed by acidic etching of the core in a sporadic manner.