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Peptide functionalized gold nanoparticles for colorimetric detection of matrilysin (MMP-7) activity
Nanyang Technology University, Singapore.
Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.ORCID iD: 0000-0002-7001-9415
Nanyang Technology University, Singapore.
2013 (English)In: Nanoscale, ISSN 2040-3364, Vol. 5, no 19, 8973-8976 p.Article in journal (Refereed) Published
Abstract [en]

A peptide with two cleavage sites for MMP-7 has been synthesized and immobilized on gold nanoparticles (AuNPs) through a cysteine residue. Digestion of the peptide by MMP-7 decreases its size and net charge, which leads to the aggregation of the AuNPs. The color shift caused by aggregation enables a direct and quantitative measurement of the concentration and activity of MMP-7 with an estimated limit of detection of 5 nM (0.1 μg mL−1).

Place, publisher, year, edition, pages
Royal Society of Chemistry , 2013. Vol. 5, no 19, 8973-8976 p.
National Category
Engineering and Technology
URN: urn:nbn:se:liu:diva-99413DOI: 10.1039/c3nr03006gISI: 000324500900027OAI: diva2:656882

Funding Agencies|School of Materials Science and Engineering, Nanyang Technological University, Singapore||Provost Office, Nanyang Technological University, Singapore||Swedish Foundation for Strategic Research (SSF)||Knut and Alice Wallenberg Foundation (KAW), CeNano||Swedish Research Council (VR)||

Available from: 2013-10-17 Created: 2013-10-17 Last updated: 2014-10-08
In thesis
1. Polypeptide functionalized gold nanoparticles for bioanalytical applications
Open this publication in new window or tab >>Polypeptide functionalized gold nanoparticles for bioanalytical applications
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Detection strategies that allow for simple, rapid, cost efficient and sensitive monitoring of proteins and their interactions with biomolecules are of great importance in drug development and diagnostics. This thesis describes the development of bioanalytical applications based on the tunable self-assembly of gold nanoparticles functionalized with a de novo designed polypeptide. Strategies for protein affinity sensing and for detection of several fundamentally important biological processes have been investigated, including Zn2+-mediated coordination between polypeptides and low molecular weight chelants and protease and phosphatase activity.

A Zn2+ responsive synthetic polypeptide designed to fold into a helix-loop-helix motif and dimerize into a four-helix bundle has been used to control the stability and self-assembly of gold nanoparticles. This polypeptide has a high negative net charge at neutral pH as a consequence of its many glutamic acid residues, efficiently preventing folding and dimerization due to charge repulsion. Zn2+ coordination provides a means to trigger folding and dimerization at neutral pH. The polypeptide can be readily attached to gold nanoparticles via a cysteine residue in the loop region, retaining its folding properties and responsiveness to Zn2+. The polypeptide functionalized gold nanoparticles display excellent colloidal stability but aggregate reversibly after addition of millimolar concentrations of Zn2+. Aggregates are dense with a defined interparticle distance corresponding to the size of the four-helix bundle, resulting in a distinct red shift of the localized surface plasmon resonance band.

Three completely different strategies for colorimetric biosensing have been developed, all being based on the same responsive hybrid nanomaterial. In the first strategy a synthetic receptor was co-immobilized on the gold nanoparticles together with the Zn2+ responsive polypeptide. Protein analyte binding to the receptor could be detected as this interaction sterically prevented aggregation induced by Zn2+. In the second strategy the reduction in colloidal stability caused by specific proteolytic cleavage of the immobilized polypeptide was exploited to monitor the enzymatic activity. The third strategy utilized the sensitivity of the system to small variations in Zn2+ concentration. The presence of low molecular weight chelants was found to influence the mode of aggregation, both by sequestering Zn2+ and through the formation of ternary complexes involving the polypeptides, which prevented dimerization and thus aggregation. This approach was further developed into a generic concept for phosphatase detection exploiting the different affinity of enzyme substrates and reaction products for Zn2+.

The flexibility of the different detection schemes enables detection of a large number of analytes by exploiting the tunable stability of the nanoparticles and the possibilities to effectively decouple the recognition event and the nanoparticle stability modulation.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2014. 62 p.
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1598
National Category
Natural Sciences
urn:nbn:se:liu:diva-106719 (URN)10.3384/diss.diva-106719 (DOI)978-91-7519-321-2 (print) (ISBN)
Public defence
2014-06-12, Plank, Fysikhuset, Campus Valla, Linköpings universitet, Linköping, 09:15 (English)
Available from: 2014-05-19 Created: 2014-05-19 Last updated: 2014-10-08Bibliographically approved

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