Abstract
Despite the high level of interest in bio-nano interactions, detailed intracellular mechanisms that govern nanoscale recognition and signalling still need to be unravelled. Magnetic nanoparticles (NPs) are valuable tools for elucidating complex intracellular bio-nano interactions. Using magnetic NPs, it is possible to isolate cell compartments that the particles interact with during intracellular trafficking. Studies at the subcellular scale rely heavily on optical microscopy; therefore, combining the advantages of magnetic recovery with excellent imaging properties to allow intracellular NP tracking is of utmost interest for the nanoscience field. However, it is a challenge to prepare highly magnetic NPs with a suitable fluorescence for the fluorescence imaging techniques typically used for biological studies. Here we present the synthesis of biocompatible multifunctional superparamagnetic multicore NPs with a bright fluorescent silica shell. The incorporation of an organic fluorophore in the silica surrounding the magnetic multicore was optimised to enable the particles to be tracked with the most common imaging techniques. To prevent dye loss resulting from silica dissolution in biological environments, which would reduce the time that the particles could be tracked, we added a thin dense encapsulating silica layer to the NPs which is highly stable in biological media. The synthesised multifunctional nanoparticles were evaluated in cell uptake experiments in which their intracellular location could be clearly identified using fluorescence imaging microscopy, even after 3 days. The magnetic properties of the iron oxide core enabled both efficient recovery of the NPs from the intracellular environment and the extraction of cell compartments involved in their intracellular trafficking. Thus, the NPs reported here provide a promising tool for the study of the processes regulating bio-nano interactions.
Highlights
There is a growing focus on determining the detailed interand intracellular mechanisms that govern nanoscale recognition and signalling.[1,2] Understanding these fundamental processes would enable further advancements in nanomedicine
We propose a mechanism of formation and a mechanism of action for the protective layer. We demonstrate that these nanoparticles can be tracked inside cells using classical and high-resolution fluorescence microscopy, and that the nanoparticles can be magnetically isolated after their journey within the cells
Investigating the interactions of NPs with cells usually relies on a combination of techniques such as fluorescence microscopy, flow cytometry and proteomics
Summary
There is a growing focus on determining the detailed interand intracellular mechanisms that govern nanoscale recognition and signalling.[1,2] Understanding these fundamental processes would enable further advancements in nanomedicine. Superparamagnetic nanoparticles (NPs) have found applications in heterogeneous catalysis,[3]. Magnetic separation is often used in purification,[13] in which the object of interest is labelled with a magnetic particle and manipulated by the application of a magnetic field.[2]. A number of studies have exploited magnetic particles for the isolation of cells,[14] viruses,[15,16] organelles,[13] exosomes[17,18] and other cell compartments.[2,13] This ability to selectively recover superparamagnetic NPs from biological environments means they are becoming an essential tool for unravelling the interactions between nanoparticles and cells.[2,13]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
