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Cellular imaging of endosome entrapped small gold nanoparticles.

Kim CS, Li X, Jiang Y, Yan B, Tonga GY, Ray M, Solfiell DJ, Rotello VM - MethodsX (2015)

Bottom Line: Information about the amount and location of sAuNPs in cells and tissues is critical to many applications.Here we use confocal laser scanning microscopy to provide endosome-entrapped sAuNP distributions and to quantify particle uptake into cells.The quantitative capabilities of the system were confirmed by inductively coupled plasma-mass spectrometry, with an observed linear relation between scattering intensity and the initial cellular uptake of sAuNPs using 4 nm and 6 nm core particles.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Massachusetts Amherst, 710 North Pleasant Street, Amherst, MA 01003, USA.

ABSTRACT
Small gold nanoparticles (sAuNPs, <10 nm in a core diameter) have been used for drug delivery and cancer therapy due to their high payload to carrier ratio. Information about the amount and location of sAuNPs in cells and tissues is critical to many applications. However, the current detection method (i.e., transmission electron microscopy) for such sAuNPs is limited due to the extensive sample preparation and the limited field of view. Here we use confocal laser scanning microscopy to provide endosome-entrapped sAuNP distributions and to quantify particle uptake into cells. The quantitative capabilities of the system were confirmed by inductively coupled plasma-mass spectrometry, with an observed linear relation between scattering intensity and the initial cellular uptake of sAuNPs using 4 nm and 6 nm core particles. The summary of the method is: •This non-invasive imaging strategy provides a tool for label-free real-time tracking and quantification of sAuNPs using a commercially available confocal laser scanning microscope.•Scattering intensity depends on particle size.•The linear relation established between scattering intensity and uptaken gold amount enables simultaneous quantitative assessment through simple image analysis.

No MeSH data available.


Representative CLSM images of intracellular AuNPs at different concentrations after 3 h of incubation in HeLa cells. (a)–(e) are 4-nm AuNPs and (f)–(j) are 6-nm AuNPs. Scale bars represent 50 μm.
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fig0015: Representative CLSM images of intracellular AuNPs at different concentrations after 3 h of incubation in HeLa cells. (a)–(e) are 4-nm AuNPs and (f)–(j) are 6-nm AuNPs. Scale bars represent 50 μm.

Mentions: Since the cellular uptake of functionalized AuNPs is dictated by NP concentration [5], we next investigated the concentration effect on the reflective imaging of intracellular AuNPs. The same gold mass concentration was chosen to compare 4- and 6-nm AuNP samples. All images were acquired with the same detector gain to ensure comparable relative intensities. No signals were observed for either NP at the lowest concentrations, and as the concentration increased, the scattering signal intensity increased as well (Fig. 3). At the same incubation concentrations, the 6-nm AuNPs gave rise to stronger signals than the 4-nm AuNPs. For 4-nm AuNPs, visible scattering signals were seen from the concentration of 20 nM (Fig. 3(c)). In the case of 6 nm AuNPs, the concentration of 2.7 nM was high enough to show scattering signals (Fig. 3(g)). These images reveal that the scattering intensity from AuNPs is concentration-dependent. Compared to 4-nm sAuNPs, the cellular uptake of 6-nm sAuNPs is dramatically more and this in turn gives rise to strong scattering signal for 6-nm sAuNPs. This result indicates the potential of our method to provide quantitative information about partial endosome-entrapped sAuNPs in addition to the visualization of intracellular sAuNPs.


Cellular imaging of endosome entrapped small gold nanoparticles.

Kim CS, Li X, Jiang Y, Yan B, Tonga GY, Ray M, Solfiell DJ, Rotello VM - MethodsX (2015)

Representative CLSM images of intracellular AuNPs at different concentrations after 3 h of incubation in HeLa cells. (a)–(e) are 4-nm AuNPs and (f)–(j) are 6-nm AuNPs. Scale bars represent 50 μm.
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4487928&req=5

fig0015: Representative CLSM images of intracellular AuNPs at different concentrations after 3 h of incubation in HeLa cells. (a)–(e) are 4-nm AuNPs and (f)–(j) are 6-nm AuNPs. Scale bars represent 50 μm.
Mentions: Since the cellular uptake of functionalized AuNPs is dictated by NP concentration [5], we next investigated the concentration effect on the reflective imaging of intracellular AuNPs. The same gold mass concentration was chosen to compare 4- and 6-nm AuNP samples. All images were acquired with the same detector gain to ensure comparable relative intensities. No signals were observed for either NP at the lowest concentrations, and as the concentration increased, the scattering signal intensity increased as well (Fig. 3). At the same incubation concentrations, the 6-nm AuNPs gave rise to stronger signals than the 4-nm AuNPs. For 4-nm AuNPs, visible scattering signals were seen from the concentration of 20 nM (Fig. 3(c)). In the case of 6 nm AuNPs, the concentration of 2.7 nM was high enough to show scattering signals (Fig. 3(g)). These images reveal that the scattering intensity from AuNPs is concentration-dependent. Compared to 4-nm sAuNPs, the cellular uptake of 6-nm sAuNPs is dramatically more and this in turn gives rise to strong scattering signal for 6-nm sAuNPs. This result indicates the potential of our method to provide quantitative information about partial endosome-entrapped sAuNPs in addition to the visualization of intracellular sAuNPs.

Bottom Line: Information about the amount and location of sAuNPs in cells and tissues is critical to many applications.Here we use confocal laser scanning microscopy to provide endosome-entrapped sAuNP distributions and to quantify particle uptake into cells.The quantitative capabilities of the system were confirmed by inductively coupled plasma-mass spectrometry, with an observed linear relation between scattering intensity and the initial cellular uptake of sAuNPs using 4 nm and 6 nm core particles.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Massachusetts Amherst, 710 North Pleasant Street, Amherst, MA 01003, USA.

ABSTRACT
Small gold nanoparticles (sAuNPs, <10 nm in a core diameter) have been used for drug delivery and cancer therapy due to their high payload to carrier ratio. Information about the amount and location of sAuNPs in cells and tissues is critical to many applications. However, the current detection method (i.e., transmission electron microscopy) for such sAuNPs is limited due to the extensive sample preparation and the limited field of view. Here we use confocal laser scanning microscopy to provide endosome-entrapped sAuNP distributions and to quantify particle uptake into cells. The quantitative capabilities of the system were confirmed by inductively coupled plasma-mass spectrometry, with an observed linear relation between scattering intensity and the initial cellular uptake of sAuNPs using 4 nm and 6 nm core particles. The summary of the method is: •This non-invasive imaging strategy provides a tool for label-free real-time tracking and quantification of sAuNPs using a commercially available confocal laser scanning microscope.•Scattering intensity depends on particle size.•The linear relation established between scattering intensity and uptaken gold amount enables simultaneous quantitative assessment through simple image analysis.

No MeSH data available.