Adipose tissue derived stem cells (ASCs) find applications in promoting tissue regeneration and wound healing process. While the molecular mechanisms of such processes are not fully understood, apparently some of these regenerative properties of ASCs are associated with secreted factors in the form of growth factors, cytokines, extracellular matrix and vesicles. Although, ASCs hold clinical relevance as a potential cell therapy candidate, widespread use of them is hindered due to inadequate data on the fate of stem cells after transplant. Hence, a method to facilitate long term tracking of the cells will allow better understanding of stem cell fate in stem cell-based therapeutics. In this study, we investigate biocompatible surface functionalized gold nanorods as optical probes for characterizing the adipogenesis and osteogenesis differentiation of ASCs using dark-field hyperspectral scattering microscopy. Hyperspectral microscopy which combines both nanoscale imaging and spectral signatures from plasmonic nanostructures provides a powerful tool for their identification and spectral analysis with previously unknown level of details. In this presentation, we would like to present our recent work on the analysis of single particle spectroscopy of gold nanorods and their orientation dependent scattering properties using hyperspectral microscopy validated with correlative high-resolution electron microscopy as well as for their use in the characterization of ASCs based on refractive index changes in the cells. Using bromide-free surfactant mixture consisting of cetyltrimethylammonium chloride and sodium oleate, fairly monodisperse gold nanorods with longitudinal surface plasmon resonance (SPR) centered around 660 nm were obtained. The nanorods were successfully characterized by UV-Visible spectroscopy, DLS, XPS, SEM and TEM results. Dark-field hyperspectral imaging experiments were performed on individual gold nanorods and their optical scattering spectra were analyzed for imaging orientation of single nanorods. Our initial results showed scattering spectra from individual gold nanorods displayed measurable spectral-shifts from their collective SPR spectrum obtained from ensemble spectroscopic measurements performed using UV-Visible spectroscopy. The detailed analysis and utility of gold nanorods in differentiation capacity of ASCs from spectral characteristics of plasmonic gold nanorods inside the cells will be summarized and discussed in this presentation.

Characterizing differentiation potential of adipose-derived stem cells using gold nanorods by dark-field hyperspectral scattering microscopy

2019 Spring National Meeting

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