Polyallylamine hydrochloride coating enhances the fluorescence emission of human serum albumin encapsulated gold nanoclusters

Ben Allan Russell, Barbara Jachimska, Yu Chen

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Protein encapsulated gold nanoclusters have received much attention due to the possibility of using them as a non-toxic fluorescent probe or marker for biomedical applications, however one major disadvantage currently is their low brightness and quantum yield in comparison to currently used fluorescent markers. A method of increasing the fluorescence emission of Human Serum Albumin (HSA) encapsulated gold nanoclusters (AuNCs) via a Polyallylamide hydrochloride (PAH) coating is described. PAH molecules with a molecular weight of ~17,500 Da were found to enhance the fluorescence emission of HSA-AuNCs by 3-fold when the protein/polymer concentration ratio is 2:1 in solution. Interestingly, the fluorescence lifetime of the AuNCs was found to decrease while the native tryptophan (TRP) fluorescence lifetime also decreased during the fluorescence emission intensity enhancement caused by the PAH binding. Coinciding with the decrease in fluorescence lifetime, the zeta potential of the system was observed to be zero during maximum fluorescence intensity enhancement, causing the formation of large aggregates. These results suggest that PAH binds to the HSA-AuNCs acting as a linker; causing aggregation and rigidification, which results in a decrease in separation between native TRP of HSA and AuNCs; improving Förster Resonance Energy Transfer (FRET) and increasing the fluorescence emission intensity. These findings are critical to the development of brighter protein encapsulated AuNCs.
LanguageEnglish
Pages131-135
Number of pages5
JournalJournal of Photochemistry and Photobiology B: Biology
Volume187
Early online date18 Aug 2018
DOIs
Publication statusPublished - 31 Oct 2018

Fingerprint

hydrochlorides
nanoclusters
albumins
Serum Albumin
Gold
serums
Fluorescence
gold
coatings
fluorescence
tryptophan
Tryptophan
proteins
life (durability)
markers
Fluorescence Resonance Energy Transfer
Proteins
polyallylamine
augmentation
Fluorescent Dyes

Keywords

  • fluorescent gold nanoclusters
  • protein encapsulated gold nanoclusters
  • fluorescence enhancement
  • forster resonance energy transfer
  • fluorescence lifetime
  • flurophore

Cite this

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title = "Polyallylamine hydrochloride coating enhances the fluorescence emission of human serum albumin encapsulated gold nanoclusters",
abstract = "Protein encapsulated gold nanoclusters have received much attention due to the possibility of using them as a non-toxic fluorescent probe or marker for biomedical applications, however one major disadvantage currently is their low brightness and quantum yield in comparison to currently used fluorescent markers. A method of increasing the fluorescence emission of Human Serum Albumin (HSA) encapsulated gold nanoclusters (AuNCs) via a Polyallylamide hydrochloride (PAH) coating is described. PAH molecules with a molecular weight of ~17,500 Da were found to enhance the fluorescence emission of HSA-AuNCs by 3-fold when the protein/polymer concentration ratio is 2:1 in solution. Interestingly, the fluorescence lifetime of the AuNCs was found to decrease while the native tryptophan (TRP) fluorescence lifetime also decreased during the fluorescence emission intensity enhancement caused by the PAH binding. Coinciding with the decrease in fluorescence lifetime, the zeta potential of the system was observed to be zero during maximum fluorescence intensity enhancement, causing the formation of large aggregates. These results suggest that PAH binds to the HSA-AuNCs acting as a linker; causing aggregation and rigidification, which results in a decrease in separation between native TRP of HSA and AuNCs; improving F{\"o}rster Resonance Energy Transfer (FRET) and increasing the fluorescence emission intensity. These findings are critical to the development of brighter protein encapsulated AuNCs.",
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author = "Russell, {Ben Allan} and Barbara Jachimska and Yu Chen",
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Polyallylamine hydrochloride coating enhances the fluorescence emission of human serum albumin encapsulated gold nanoclusters. / Russell, Ben Allan; Jachimska, Barbara; Chen, Yu.

In: Journal of Photochemistry and Photobiology B: Biology, Vol. 187, 31.10.2018, p. 131-135.

Research output: Contribution to journalArticle

TY - JOUR

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AU - Chen, Yu

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AB - Protein encapsulated gold nanoclusters have received much attention due to the possibility of using them as a non-toxic fluorescent probe or marker for biomedical applications, however one major disadvantage currently is their low brightness and quantum yield in comparison to currently used fluorescent markers. A method of increasing the fluorescence emission of Human Serum Albumin (HSA) encapsulated gold nanoclusters (AuNCs) via a Polyallylamide hydrochloride (PAH) coating is described. PAH molecules with a molecular weight of ~17,500 Da were found to enhance the fluorescence emission of HSA-AuNCs by 3-fold when the protein/polymer concentration ratio is 2:1 in solution. Interestingly, the fluorescence lifetime of the AuNCs was found to decrease while the native tryptophan (TRP) fluorescence lifetime also decreased during the fluorescence emission intensity enhancement caused by the PAH binding. Coinciding with the decrease in fluorescence lifetime, the zeta potential of the system was observed to be zero during maximum fluorescence intensity enhancement, causing the formation of large aggregates. These results suggest that PAH binds to the HSA-AuNCs acting as a linker; causing aggregation and rigidification, which results in a decrease in separation between native TRP of HSA and AuNCs; improving Förster Resonance Energy Transfer (FRET) and increasing the fluorescence emission intensity. These findings are critical to the development of brighter protein encapsulated AuNCs.

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