Exploring High Aspect Ratio Gold Nanotubes as Cytosolic Agents: Structural Engineering and Uptake into Mesothelioma Cells

Our plain-English summary of Exploring High Aspect Ratio Gold Nanotubes as Cytosolic Agents: Structural Engineering and Uptake into Mesothelioma Cells, by S. Ye, A.A. Azad, J.E. Chambers, et al (Small, 2020).

The study

• Authors: S. Ye, A.A. Azad, J.E. Chambers, A.J. Beckett, L. Roach, S.C.T. Moorcroft, Z. Aslam, I.A. Prior, A.F. Markham, P.L. Coletta, S.J. Marciniak, S.D. Evans
• Journal: Small
• Published: 2020;16(46):e2003793
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The generation of effective and safe nanoagents for biological applications requires their physicochemical characteristics to be tunable, and their cellular interactions to be well characterized. Here, the controlled synthesis is developed for preparing high-aspect ratio gold nanotubes (AuNTs) with tailorable wall thickness, microstructure, composition, and optical characteristics. The modulation of optical properties generates AuNTs with strong near infrared absorption. Surface modification enhances dispersibility of AuNTs in aqueous media and results in low cytotoxicity. The uptake and trafficking of these AuNTs by primary mesothelioma cells demonstrate their accumulation in a perinuclear distribution where they are confined initially in membrane-bound vesicles from which they ultimately escape to the cytosol. This represents the first study of the cellular interactions of high-aspect ratio 1D metal nanomaterials and will facilitate the rational design of plasmonic nanoconstructs as cytosolic nanoagents for potential diagnosis and therapeutic applications.

© 2020 The Authors. Published by Wiley-VCH GmbH.

In plain English

This was a laboratory study. It did not study asbestos exposure or people. The authors developed a room-temperature method for making long, thin, hollow gold nanotubes from silver nanowire templates. They tested the nanotubes on primary mesothelioma cells (Meso-7T, from MesobanK in the UK) grown in dishes. Changing the template set the wall thickness between 7 and 25 nm. Changing the amount of gold tuned the tubes to absorb near-infrared light. The coated nanotubes used on cells averaged about 10 micrometres long. At 5 and 25 micrograms per mL, over 6 to 48 hours, no significant toxicity to the cells was seen. The cells took in the nanotubes and moved them toward the nucleus. At 6 hours some nanotubes were inside membrane-bound sacs and some were free in the cell fluid. By 18 hours they were found only free in the cell fluid. With near-infrared laser light, nanotubes at 12.5 micrograms per mL lowered cell viability to 50.7% (p less than 0.01). Laser light alone did not kill cells. The authors concluded the nanotubes could potentially be developed for light-triggered delivery of treatments.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory (in vitro) study: synthesis and characterization of gold nanotubes, followed by experiments on cultured mesothelioma cells
• Who was studied: Primary mesothelioma cells (Meso-7T) obtained from MesobanK, UK, grown in culture; no human participants
• Exposure: Cells were exposed to gold nanotubes coated with thiol-PEG-FITC (gold-silver alloy walls), not to asbestos. Examination of 100 of these nanotubes gave a length of 10.1 plus or minus 3.9 micrometres, a wall thickness of about 12 nm and an aspect ratio of about 80. Concentrations were 5, 12.5 and 25 micrograms per mL, with or without 875 nm near-infrared laser light.
• Main results:
  • Nanotube wall thickness could be set between 7 and 25 nm by changing the silver nanowire template
  • As the gold percentage of the nanotubes rose from 31.6% to 59.0%, their main light-absorption peak shifted from 620 to 926 nm (toward near-infrared)
  • Coated nanotubes at 5 and 25 micrograms per mL caused no significant toxicity to Meso-7T cells over 6, 18, 24 and 48 hours
  • In live-cell tracking, 80% of identifiable nanotube tracks (n = 221) moved faster than a previously reported speed threshold for active uptake
  • After 18 hours, nanotubes inside the cells were mainly located around the nucleus
  • Nanotubes showed moderate but incomplete overlap with markers for lysosomes (LAMP1) and lysosomes/late endosomes (LAMP3)
  • By electron microscopy, at 6 hours nanotubes were found both free in the cell fluid and inside vesicles; by 18 hours they were found only free in the cell fluid
  • In water under laser light, the largest temperature rise, 8.8 °C, occurred at a nanotube concentration of 12.5 micrograms per mL
  • Laser light alone did not kill Meso-7T cells. With nanotubes at 12.5 micrograms per mL plus laser, cell viability fell to 50.7% (p less than 0.01).
• The authors' conclusion: The authors concluded that the nanotubes were taken up by primary mesothelioma cells, moved to the area around the nucleus, and eventually escaped membrane-bound vesicles into the cell fluid. In their view, this gives the nanotubes potential for light-triggered delivery of therapeutic molecules.
• Limitations the authors state:
  • The fluorescent FITC label tends to be quenched inside cells, and a preliminary assessment showed it partly detached from the nanotubes after uptake, so reflectance microscopy was used instead

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Aspect Ratio (Length-to-diameter ratio), Mesothelioma.

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