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Characterization and visualization of vesicles in the endo-lysosomal pathway with surface-enhanced Raman spectroscopy and chemometrics

Characterization and visualization of vesicles in the endo-lysosomal pathway with surface-enhanced Raman spectroscopy and chemometrics
Characterization and visualization of vesicles in the endo-lysosomal pathway with surface-enhanced Raman spectroscopy and chemometrics
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.
surface-enhanced raman spectroscopy, endocytosis, endosomes, lysosomes, linear discriminant analysis, chemometrics, cells
1936-0851
307-316
Huefner, Anna
135d7fc3-aff0-4135-b98b-2c070e795ac0
Kuan, Wei-Li
f32d8025-2376-4408-a285-3f3d9fc11bdc
Müller, Karin H.
122c813f-450c-40fd-9014-2c96659b02b3
Skepper, Jeremy N.
47f83298-b8d6-4cdd-b201-05f37363dd41
Barker, Roger A.
64e07f34-66db-42a7-9a28-2cb3070f63ad
Mahajan, Sumeet
b131f40a-479e-4432-b662-19d60d4069e9
Huefner, Anna
135d7fc3-aff0-4135-b98b-2c070e795ac0
Kuan, Wei-Li
f32d8025-2376-4408-a285-3f3d9fc11bdc
Müller, Karin H.
122c813f-450c-40fd-9014-2c96659b02b3
Skepper, Jeremy N.
47f83298-b8d6-4cdd-b201-05f37363dd41
Barker, Roger A.
64e07f34-66db-42a7-9a28-2cb3070f63ad
Mahajan, Sumeet
b131f40a-479e-4432-b662-19d60d4069e9

Huefner, Anna, Kuan, Wei-Li, Müller, Karin H., Skepper, Jeremy N., Barker, Roger A. and Mahajan, Sumeet (2016) Characterization and visualization of vesicles in the endo-lysosomal pathway with surface-enhanced Raman spectroscopy and chemometrics. ACS Nano, 10 (1), 307-316. (doi:10.1021/acsnano.5b04456).

Record type: Article

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 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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More information

Accepted/In Press date: 9 December 2015
e-pub ahead of print date: 9 December 2015
Published date: January 2016
Keywords: surface-enhanced raman spectroscopy, endocytosis, endosomes, lysosomes, linear discriminant analysis, chemometrics, cells
Organisations: Institute for Life Sciences, Chemical Biology Group

Identifiers

Local EPrints ID: 384984
URI: http://eprints.soton.ac.uk/id/eprint/384984
ISSN: 1936-0851
PURE UUID: 5763782c-1b92-4865-8206-d4b2758ccbaa
ORCID for Sumeet Mahajan: ORCID iD orcid.org/0000-0001-8923-6666

Catalogue record

Date deposited: 14 Jan 2016 15:21
Last modified: 18 Feb 2021 17:09

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