Cellulose is a naturally occurring polymer of glucose. Cellulose based nanofibers and nanoparticles (CNPs) are characterized by their large surface area, high aspect ratio, and high Young’s modulus, leading to potential applications in packaging, sensing, electronics. Further, a major attraction of CNPs for biomedicine is that they biodegrade to glucose, whereas traditionally used polymers such as PLGA degrade to inflammatory acidic components. Conventionally, CNPs have been produced by acid hydrolysis, enzyme treatment or chemical oxidation of natural product cellulose, with inefficient and cumbersome protocols. Here, we demonstrate the synthesis of spherical CNPs using a facile oil in water (o/w) emulsification technique, starting with cellulose triacetate. This unique strategy can be used to encapsulate hydrophobic superparamagnetic and/or X-ray dense nanocrystals (NCs) for MRI and X-ray CT applications. In this work, we first fabricated spherical cellulose triacetate nanoparticles (CTNPs). Next, these CTNPs were subjected to alkaline saponification to re-generate spherical CNPs. An optimized process (base concentration, reaction time) provides a major improvement over previous reports pertaining to the size and structural integrity of final CNPs. All NPs produced were extensively characterized using a variety of techniques; DLS, SEM, TEM, IR and ICP-OES. Further, this strategy was used to encapsulate superparamagnetic iron oxide NCs within CTNPs and CNPs. The resulting iron oxide CTNPs (IO-CTNPs) exhibit high in vitro cell viability. Subsequently, in this work we report the base-catalyzed regeneration of IO-CNPs from the IO-CTNPs, their detailed characterization, extensive in vitro biocompatibility and in vivo MRI. In addition, co-encapsulation of X-ray dense TaOx NCs within the CNPs together with CT evaluation of the resulting TaOx-CNPs is demonstrated.

Spherical cellulose nanoparticles (CNPs) for magnetic resonance imaging (MRI) and X-ray computed tomography (CT)

2019 Fall National Meeting

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