Engineering
of water-dispersible Gd
3+
ions-decorated reduced graphene
oxide (Gd-rGO) nanosheets (NSs) has been performed. The multifunctional
capability of the sample was studied as a novel contrast agent for
swept source optical coherence tomography and magnetic resonance imaging,
and also as an efficient drug-delivery nanovehicle. The synthesized
samples were fabricated in a chemically stable condition, and efforts
have been put toward improving its biocompatibility by functionalizing
with carbohydrates molecules. Gd incorporation in rGO matrix enhanced
the fluorouracil (5-FU) drug loading capacity by 34%. The release
of the drug was ∼92% within 72 h. Gd-rGO nanosheets showed
significant contrast in comparison to optically responsive bare GO
for swept source optical coherence tomography. The longitudinal relaxivity
rate (
r
1
) of 16.85 mM
–1
s
–1
for Gd-rGO was recorded, which was 4 times
larger than that of the commercially used clinical contrast agent
Magnevist (4 mM
–1
s
–1
) at a magnetic
field strength of 1.5 T.
Interrogating multiple fiber Bragg gratings (FBG) requires highly sensitive spectrum scanning equipment such as optical spectrum analyzers, tunable filters, acousto-optic tunable filters etc, which are expensive, bulky and time consuming. In this paper, we present a new approach for multiple FBG sensor interrogation using long-period gratings and an artificial neural network. The reflection spectra of the multiplexed FBGs are modulated by two long period gratings separately and the modulated optical intensities were detected by two photodetectors. The outputs of the detectors are then used as input in a previously trained artificial neural network to interrogate the FBG sensors. Simulations have been performed to determine the strain and wavelength shift using two and four sensors. The interrogation system has also been demonstrated experimentally for two sensors using simply supported beams in the range of 0–350 μstrain. The proposed interrogation scheme has been found to identify the perturbed FBG, and to determine strain and wavelength shift with reasonable accuracy.
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