Micro-Computed Tomography Detection of Gold Nanoparticle-Labelled Mesenchymal Stem Cells in the Rat Subretinal Layer

Abstract

Mesenchymal stem cells are widely used in many pre-clinical and clinical settings. Despite advances in molecular technology; the migration and homing activities of these cells in in vivo systems are not well understood. Labelling mesenchymal stem cells with gold nanoparticles has no cytotoxic effect and may offer suitable indications for stem cell tracking. Here, we report a simple protocol to label mesenchymal stem cells using 80 nm gold nanoparticles. Once the cells and particles were incubated together for 24 h, the labelled products were injected into the rat subretinal layer. Micro-computed tomography was then conducted on the 15th and 30th day post-injection to track the movement of these cells, as visualized by an area of hyperdensity from the coronal section images of the rat head. In addition, we confirmed the cellular uptake of the gold nanoparticles by the mesenchymal stem cells using transmission electron microscopy. As opposed to other methods, the current protocol provides a simple, less labour-intensive and more efficient labelling mechanism for real-time cell tracking. Finally, we discuss the potential manipulations of gold nanoparticles in stem cells for cell replacement and cancer therapy in ocular disorders or diseases.

X-ray computed tomography in life sciences

“…The high atomic number of gold (atomic number = 79) means that nanoparticles attenuate X-rays to a much greater degree than soft tissues, providing good imaging contrast. Regarding concerns over toxicity [63,64], many studies report that gold nanoparticles are not detrimental to the functionality of the therapeutic cell, as observed in mesenchymal stem cells, human T cells, A-431 human squamous carcinoma cells and monocytes, among others [65][66][67]. The ecotoxicology of nanoparticles has also been considered by observing their uptake and expulsion over time in B. glabrata freshwater snails [68].…”

Gold nanoparticles in ophthalmology

“…It was shown that these GNR functionalized with polyethylene glycol (PEG) groups did not affect the viability and proliferation even after 10 days of continuous cell culture. The GNR‐labeled cells were then subretinally injected in rats’ eyes . More than 1 month after their injection, the GNP‐labeled cells were still detectable by microcomputed tomography, which is based on the attenuation of X rays passing through the cells.…”

Application of Nanomaterials in Biomedical Imaging and Cancer Therapy

“…Their most adventitious property is being able to migrate into different tissue, and monitoring this migration is very beneficial for studying metastases. A study was done to observe such migration of mesenchymal cells using Au NPs as a marker, and a micro CT was used to obtain movement information from the Au NP marker [ 41 ]. The study observed the comparison between porous and solid Au NPs as a contrast agent and their effect on the liver and kidney.…”