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Size-selected silver clusters on polymer surfaces as plasmonic transducers for nano-biosensors
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Orientador(es)
Resumo(s)
The phenomenon of localized surface plasmon resonance (LSPR) was used for detection of
proteins incubated on size-selected silver clusters embedded in poly (methyl methacrylate)
(PMMA) layers. The silver clusters were produced by magnetron sputtering and subsequently sizeselected
by electrostatic quadrupole mass spectrometer (EQMS).
The size-selection process was followed by the deposition of silver clusters with low kinetic
energies, i.e. in a soft-landing regime on PMMA, in order to avoid the deformation and/or fragmentation
of the silver clusters.
The role of PMMA hardness (viscosity) on cluster immersion was investigated to control the
homogeneity in distribution of clusters, which can be partly or fully embedded in PMMA.
The viscosity of the polymers was found to be an essential part in the immersion of the silver
nanoparticles into the polymer, which can be controlled through tuning of its viscosity or hardness
utilizing simple thermal annealing of the samples.
The optical properties of the silver clusters - in particular the localized surface plasmon resonance
(LSPR) – were measured with the optical absorption spectra of the silver clusters, in which
was possible to clearly identify an intensity and a resonance band of the deposited clusters.
Proteins of interest were incubated on the clusters utilizing antibody-antigen scheme and
clear change in the parameters of the LSPR band was observed allowing protein detection and
demonstrating applicability of the fabricated composites in bio-sensing.
Descrição
Palavras-chave
Optical nano-biosensors localized plasmon resonance