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Characterization and Visualization of Vesicles in the Endo-Lysosomal Pathway with Surface-Enhanced Raman Spectroscopy and Chemometrics

Huefner, Anna; Kuan, Wei-Li; Müller, Karin H; Skepper, Jeremy N; Barker, Roger A LU and Mahajan, Sumeet (2016) In ACS Nano 10(1). p.16-307
Abstract

Surface-enhanced Raman spectroscopy (SERS) is an ultrasensitive vibrational fingerprinting technique widely used in analytical and biosensing applications. For intracellular sensing, typically gold nanoparticles (AuNPs) are employed as transducers to enhance the otherwise weak Raman spectroscopy signals. Thus, the signature patterns of the molecular nanoenvironment around intracellular unlabeled AuNPs can be monitored in a reporter-free manner by SERS. The challenge of selectively identifying molecular changes resulting from cellular processes in large and multidimensional data sets and the lack of simple tools for extracting this information has resulted in limited characterization of fundamental cellular processes by SERS. Here, this... (More)

Surface-enhanced Raman spectroscopy (SERS) is an ultrasensitive vibrational fingerprinting technique widely used in analytical and biosensing applications. For intracellular sensing, typically gold nanoparticles (AuNPs) are employed as transducers to enhance the otherwise weak Raman spectroscopy signals. Thus, the signature patterns of the molecular nanoenvironment around intracellular unlabeled AuNPs can be monitored in a reporter-free manner by SERS. The challenge of selectively identifying molecular changes resulting from cellular processes in large and multidimensional data sets and the lack of simple tools for extracting this information has resulted in limited characterization of fundamental cellular processes by SERS. Here, this shortcoming in analysis of SERS data sets is tackled by developing a suitable methodology of reference-based PCA-LDA (principal component analysis-linear discriminant analysis). This method is validated and exemplarily used to extract spectral features characteristic of the endocytic compartment inside cells. The voluntary uptake through vesicular endocytosis is widely used for the internalization of AuNPs into cells, but the characterization of the individual stages of this pathway has not been carried out. Herein, we use reporter-free SERS to identify and visualize the stages of endocytosis of AuNPs in cells and map the molecular changes via the adaptation and advantageous use of chemometric methods in combination with tailored sample preparation. Thus, our study demonstrates the capabilities of reporter-free SERS for intracellular analysis and its ability to provide a way of characterizing intracellular composition. The developed analytical approach is generic and enables the application of reporter-free SERS to identify unknown components in different biological matrices and materials.

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author
publishing date
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Contribution to journal
publication status
published
keywords
Biological Transport, Cell Line, Tumor, DNA, Discriminant Analysis, Endocytosis, Endosomes, Gold, Humans, Hydrolysis, Lysosomes, Metal Nanoparticles, Neurons, Principal Component Analysis, RNA, Spectrum Analysis, Raman, Journal Article, Research Support, Non-U.S. Gov't
in
ACS Nano
volume
10
issue
1
pages
10 pages
publisher
The American Chemical Society
external identifiers
  • scopus:84989291241
ISSN
1936-086X
DOI
10.1021/acsnano.5b04456
language
English
LU publication?
no
id
c283a470-18ef-48ac-8f81-cf7b611f04cb
date added to LUP
2016-11-23 13:17:09
date last changed
2017-09-17 09:32:59
@article{c283a470-18ef-48ac-8f81-cf7b611f04cb,
  abstract     = {<p>Surface-enhanced Raman spectroscopy (SERS) is an ultrasensitive vibrational fingerprinting technique widely used in analytical and biosensing applications. For intracellular sensing, typically gold nanoparticles (AuNPs) are employed as transducers to enhance the otherwise weak Raman spectroscopy signals. Thus, the signature patterns of the molecular nanoenvironment around intracellular unlabeled AuNPs can be monitored in a reporter-free manner by SERS. The challenge of selectively identifying molecular changes resulting from cellular processes in large and multidimensional data sets and the lack of simple tools for extracting this information has resulted in limited characterization of fundamental cellular processes by SERS. Here, this shortcoming in analysis of SERS data sets is tackled by developing a suitable methodology of reference-based PCA-LDA (principal component analysis-linear discriminant analysis). This method is validated and exemplarily used to extract spectral features characteristic of the endocytic compartment inside cells. The voluntary uptake through vesicular endocytosis is widely used for the internalization of AuNPs into cells, but the characterization of the individual stages of this pathway has not been carried out. Herein, we use reporter-free SERS to identify and visualize the stages of endocytosis of AuNPs in cells and map the molecular changes via the adaptation and advantageous use of chemometric methods in combination with tailored sample preparation. Thus, our study demonstrates the capabilities of reporter-free SERS for intracellular analysis and its ability to provide a way of characterizing intracellular composition. The developed analytical approach is generic and enables the application of reporter-free SERS to identify unknown components in different biological matrices and materials.</p>},
  author       = {Huefner, Anna and Kuan, Wei-Li and Müller, Karin H and Skepper, Jeremy N and Barker, Roger A and Mahajan, Sumeet},
  issn         = {1936-086X},
  keyword      = {Biological Transport,Cell Line, Tumor,DNA,Discriminant Analysis,Endocytosis,Endosomes,Gold,Humans,Hydrolysis,Lysosomes,Metal Nanoparticles,Neurons,Principal Component Analysis,RNA,Spectrum Analysis, Raman,Journal Article,Research Support, Non-U.S. Gov't},
  language     = {eng},
  month        = {01},
  number       = {1},
  pages        = {16--307},
  publisher    = {The American Chemical Society},
  series       = {ACS Nano},
  title        = {Characterization and Visualization of Vesicles in the Endo-Lysosomal Pathway with Surface-Enhanced Raman Spectroscopy and Chemometrics},
  url          = {http://dx.doi.org/10.1021/acsnano.5b04456},
  volume       = {10},
  year         = {2016},
}