Human serum albumin encapsulated gold nanoclusters

effects of cluster synthesis on natural protein characteristics

B. A. Russell, B. Jachimska, I. Kralka, P. A. Mulheran, Y. Chen

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Abstract

The differences in physiochemical properties between native Human Serum Albumin (HSA) and HSA encapsulated gold nanoclusters (HSA-AuNCs) are characterised. The molecules light absorbance (UV/Vis), electrophoretic mobility, dynamic viscosity, density, hydrodynamic radius (DLS), absorption (QCM) and chemical bonding (XPS) characteristics were studied. The UV/Vis and DLS data shows the formation of large aggregates for HSA-AuNCs between pH 4-6 which is not observed for native HSA. This observation was further supported by QCM measurements showing a large increase in mass adsorbed at pH 6 between HSA and HSA-AuNCs. The DLS data also reveals a hydrodynamic radius of 12nm for HSA-AuNCs, nearly double that of 7nm for native HSA at pH higher than 6, suggesting the formation of compact HSA-AuNCs dimers. The electrophoretic mobility data for both HSA-AuNCs and HSA were converted to zeta potentials. The zeta potential of HSA-AuNCs was seen to be more negative between pH6-12, suggesting that the protein surface is interacting with unreacted gold salt anions. Measurements of density and viscosity were also found to be in agreement with previous data suggesting HSA-AuNCs forms aggregates. XPS data also suggests that not all reactants are used up during the HSA-AuNCs synthesis and positive side chains play a part in the initial synthesis stages. It was concluded that HSA-AuNCs most likely form dimers at natural and high pH. Between pH 4-6 HSA-AuNCs form very large aggregates limiting their use as a fluorescent probe in this pH range. It was also found that the native characteristics of HSA are altered upon HSA-AuNCs synthesis which needs to be taken into consideration when applying HSA-AuNCs as a fluorescent probe in all fluorescent imaging and sensing.
Original languageEnglish
Number of pages7
JournalJournal of Materials Chemistry B
Early online date29 Sep 2016
DOIs
Publication statusE-pub ahead of print - 29 Sep 2016

Fingerprint

Nanoclusters
nanoclusters
albumins
Serum Albumin
Gold
serums
Electrophoretic mobility
Zeta potential
gold
proteins
Proteins
Dimers
synthesis
Hydrodynamics
X ray photoelectron spectroscopy
Viscosity
Ultraviolet radiation
Negative ions
Salts
Imaging techniques

Keywords

  • gold nanoclusters
  • human serum albumin
  • physiochemical properties
  • light absorbance
  • electrophoretic mobility
  • dynamic viscosity
  • density
  • hydrodynamic radius
  • absorption
  • chemical bonding
  • fluorophores

Cite this

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title = "Human serum albumin encapsulated gold nanoclusters: effects of cluster synthesis on natural protein characteristics",
abstract = "The differences in physiochemical properties between native Human Serum Albumin (HSA) and HSA encapsulated gold nanoclusters (HSA-AuNCs) are characterised. The molecules light absorbance (UV/Vis), electrophoretic mobility, dynamic viscosity, density, hydrodynamic radius (DLS), absorption (QCM) and chemical bonding (XPS) characteristics were studied. The UV/Vis and DLS data shows the formation of large aggregates for HSA-AuNCs between pH 4-6 which is not observed for native HSA. This observation was further supported by QCM measurements showing a large increase in mass adsorbed at pH 6 between HSA and HSA-AuNCs. The DLS data also reveals a hydrodynamic radius of 12nm for HSA-AuNCs, nearly double that of 7nm for native HSA at pH higher than 6, suggesting the formation of compact HSA-AuNCs dimers. The electrophoretic mobility data for both HSA-AuNCs and HSA were converted to zeta potentials. The zeta potential of HSA-AuNCs was seen to be more negative between pH6-12, suggesting that the protein surface is interacting with unreacted gold salt anions. Measurements of density and viscosity were also found to be in agreement with previous data suggesting HSA-AuNCs forms aggregates. XPS data also suggests that not all reactants are used up during the HSA-AuNCs synthesis and positive side chains play a part in the initial synthesis stages. It was concluded that HSA-AuNCs most likely form dimers at natural and high pH. Between pH 4-6 HSA-AuNCs form very large aggregates limiting their use as a fluorescent probe in this pH range. It was also found that the native characteristics of HSA are altered upon HSA-AuNCs synthesis which needs to be taken into consideration when applying HSA-AuNCs as a fluorescent probe in all fluorescent imaging and sensing.",
keywords = "gold nanoclusters, human serum albumin, physiochemical properties, light absorbance, electrophoretic mobility, dynamic viscosity, density, hydrodynamic radius, absorption, chemical bonding, fluorophores",
author = "Russell, {B. A.} and B. Jachimska and I. Kralka and Mulheran, {P. A.} and Y. Chen",
year = "2016",
month = "9",
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doi = "10.1039/C6TB01827K",
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TY - JOUR

T1 - Human serum albumin encapsulated gold nanoclusters

T2 - effects of cluster synthesis on natural protein characteristics

AU - Russell, B. A.

AU - Jachimska, B.

AU - Kralka, I.

AU - Mulheran, P. A.

AU - Chen, Y.

PY - 2016/9/29

Y1 - 2016/9/29

N2 - The differences in physiochemical properties between native Human Serum Albumin (HSA) and HSA encapsulated gold nanoclusters (HSA-AuNCs) are characterised. The molecules light absorbance (UV/Vis), electrophoretic mobility, dynamic viscosity, density, hydrodynamic radius (DLS), absorption (QCM) and chemical bonding (XPS) characteristics were studied. The UV/Vis and DLS data shows the formation of large aggregates for HSA-AuNCs between pH 4-6 which is not observed for native HSA. This observation was further supported by QCM measurements showing a large increase in mass adsorbed at pH 6 between HSA and HSA-AuNCs. The DLS data also reveals a hydrodynamic radius of 12nm for HSA-AuNCs, nearly double that of 7nm for native HSA at pH higher than 6, suggesting the formation of compact HSA-AuNCs dimers. The electrophoretic mobility data for both HSA-AuNCs and HSA were converted to zeta potentials. The zeta potential of HSA-AuNCs was seen to be more negative between pH6-12, suggesting that the protein surface is interacting with unreacted gold salt anions. Measurements of density and viscosity were also found to be in agreement with previous data suggesting HSA-AuNCs forms aggregates. XPS data also suggests that not all reactants are used up during the HSA-AuNCs synthesis and positive side chains play a part in the initial synthesis stages. It was concluded that HSA-AuNCs most likely form dimers at natural and high pH. Between pH 4-6 HSA-AuNCs form very large aggregates limiting their use as a fluorescent probe in this pH range. It was also found that the native characteristics of HSA are altered upon HSA-AuNCs synthesis which needs to be taken into consideration when applying HSA-AuNCs as a fluorescent probe in all fluorescent imaging and sensing.

AB - The differences in physiochemical properties between native Human Serum Albumin (HSA) and HSA encapsulated gold nanoclusters (HSA-AuNCs) are characterised. The molecules light absorbance (UV/Vis), electrophoretic mobility, dynamic viscosity, density, hydrodynamic radius (DLS), absorption (QCM) and chemical bonding (XPS) characteristics were studied. The UV/Vis and DLS data shows the formation of large aggregates for HSA-AuNCs between pH 4-6 which is not observed for native HSA. This observation was further supported by QCM measurements showing a large increase in mass adsorbed at pH 6 between HSA and HSA-AuNCs. The DLS data also reveals a hydrodynamic radius of 12nm for HSA-AuNCs, nearly double that of 7nm for native HSA at pH higher than 6, suggesting the formation of compact HSA-AuNCs dimers. The electrophoretic mobility data for both HSA-AuNCs and HSA were converted to zeta potentials. The zeta potential of HSA-AuNCs was seen to be more negative between pH6-12, suggesting that the protein surface is interacting with unreacted gold salt anions. Measurements of density and viscosity were also found to be in agreement with previous data suggesting HSA-AuNCs forms aggregates. XPS data also suggests that not all reactants are used up during the HSA-AuNCs synthesis and positive side chains play a part in the initial synthesis stages. It was concluded that HSA-AuNCs most likely form dimers at natural and high pH. Between pH 4-6 HSA-AuNCs form very large aggregates limiting their use as a fluorescent probe in this pH range. It was also found that the native characteristics of HSA are altered upon HSA-AuNCs synthesis which needs to be taken into consideration when applying HSA-AuNCs as a fluorescent probe in all fluorescent imaging and sensing.

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KW - human serum albumin

KW - physiochemical properties

KW - light absorbance

KW - electrophoretic mobility

KW - dynamic viscosity

KW - density

KW - hydrodynamic radius

KW - absorption

KW - chemical bonding

KW - fluorophores

UR - http://www.rsc.org/journals-books-databases/about-journals/journal-of-materials-chemistry-b/

U2 - 10.1039/C6TB01827K

DO - 10.1039/C6TB01827K

M3 - Article

JO - Journal of Materials Chemistry B

JF - Journal of Materials Chemistry B

SN - 2050-750X

ER -