A robust liposomal platform for direct colorimetric detection of sphingomyelinase enzyme and inhibitors

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Title: A robust liposomal platform for direct colorimetric detection of sphingomyelinase enzyme and inhibitors
Author(s): Holme, MN
Rana, S
Barriga, H
Kauscher, U
Brooks, NJ
Stevens, MM
Item Type: Journal Article
Abstract: The enzyme sphingomyelinase (SMase) is an important biomarker for several diseases such as Niemann Pick’s, atherosclerosis, multiple sclerosis, and HIV. We present a two-component colorimetric SMase activity assay that is more sensitive and much faster than currently available commercial assays. Herein, SMase-triggered release of cysteine from a sphingomyelin (SM)-based liposome formulation with 60 mol % cholesterol causes gold nanoparticle (AuNP) aggregation, enabling colorimetric detection of SMase activities as low as 0.02 mU/mL, corresponding to 1.4 pM concentration. While the lipid composition offers a stable, nonleaky liposome platform with minimal background signal, high specificity toward SMase avoids cross-reactivity of other similar phospholipases. Notably, use of an SM-based liposome formulation accurately mimics the natural in vivo substrate: the cell membrane. We studied the physical rearrangement process of the lipid membrane during SMase-mediated hydrolysis of SM to ceramide using small- and wide-angle X-ray scattering. A change in lipid phase from a liquid to gel state bilayer with increasing concentration of ceramide accounts for the observed increase in membrane permeability and consequent release of encapsulated cysteine. We further demonstrated the effectiveness of the sensor in colorimetric screening of small-molecule drug candidates, paving the way for the identification of novel SMase inhibitors in minutes. Taken together, the simplicity, speed, sensitivity, and naked-eye readout of this assay offer huge potential in point-of-care diagnostics and high-throughput drug screening.
Publication Date: 28-Aug-2018
Date of Acceptance: 20-Jul-2018
URI: http://hdl.handle.net/10044/1/62829
DOI: https://dx.doi.org/10.1021/acsnano.8b03308
ISSN: 1936-0851
Publisher: American Chemical Society
Start Page: 8197
End Page: 8207
Journal / Book Title: ACS Nano
Volume: 12
Issue: 8
Sponsor/Funder: Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (E
Engineering & Physical Science Research Council (EPSRC)
Commission of the European Communities
Commission of the European Communities
Commission of the European Communities
Funder's Grant Number: EP/J017566/1
EP/K031953/1
EP/K020641/1
PIIF-GA-2013-629218
ERC-2013-CoG-616417
PIEF-GA-2013-626766
Copyright Statement: © 2018 American Chemical Society. his is an open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. (https://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html)
Keywords: Science & Technology
Physical Sciences
Technology
Chemistry, Multidisciplinary
Chemistry, Physical
Nanoscience & Nanotechnology
Materials Science, Multidisciplinary
Chemistry
Science & Technology - Other Topics
Materials Science
liposome
gold nanoparticle
sphingomyelinase
colorimetric detection
sphingomyelin
cholesterol
NIEMANN-PICK-DISEASE
TEMPERATURE PHASE-BEHAVIOR
TANDEM MASS-SPECTROMETRY
ACID SPHINGOMYELINASE
GOLD NANOPARTICLES
NEUTRAL SPHINGOMYELINASE
NATURAL SPHINGOMYELIN
CERAMIDE
ASSAY
CHOLESTEROL
cholesterol
colorimetric detection
gold nanoparticle
liposome
sphingomyelin
sphingomyelinase
MD Multidisciplinary
Nanoscience & Nanotechnology
Publication Status: Published
Open Access location: http://dx.doi.org/10.1021/acsnano.8b0330
Online Publication Date: 2018-08-06
Appears in Collections:Faculty of Engineering
Materials
Chemistry
Biological and Biophysical Chemistry
Faculty of Natural Sciences



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