3 research outputs found
Electrospun Composite Bead-on-String Nanofibers Containing CaO<sub>2</sub> Nanoparticles and MnO<sub>2</sub> Nanosheets as Oxygen-Release Systems for Biomedical Applications
Oxygen-generating
biomaterials have the potential to improve tissue
engineering and regenerative therapeutic strategies. However, the
development of such materials capable of controlling the local partial
pressure of oxygen (pO2) in the long term is still a major
challenge. Here we report nanostructured composite membranes comprising
electrospun fibers exhibiting a bead-on-string structure as a controlled
oxygen-release system for periodontitis treatment. For this, calcium
peroxide nanoparticles (CaO2 NPs) and manganese dioxide
nanosheets (MnO2 NSs) were incorporated into the structure
of hydrophobic electrospun poly (lactic acid) (PLA)-based nanofibers.
We use CaO2 NPs as hydrogen peroxide (H2O2)-generating precursors when exposed to water, while MnO2 NSs were applied as a nanozyme to catalyze the decomposition
of H2O2 to the final oxygen product. Our results
revealed that the beads on the fibrous structure acted as reservoirs
of CaO2 NPs and MnO2 NSs. Moreover, the composite
membranes provided sustained oxygen release over 7 days, where levels
were modulated by the CaO2 NP content. Such constructs
exhibited suitable physicochemical properties and antimicrobial activities
against some bacteria (e.g., Porphyromonas gingivalis and Treponema denticola) typically
associated with aggressive and chronic periodontitis. In vitro studies
also revealed that the membranes were not cytotoxic toward human oral
keratinocyte (Nok-si) cells as well as enhanced the cell viability
when high content of CaO2 NP and MnO2 NS were
incorporated into the fiber’s structure. Taken together, our
results demonstrate that the nanostructured composite membranes show
potential to be employed as oxygen-release platforms for periodontal
tissue regeneration
Electrospun Polyamide 6/Poly(allylamine hydrochloride) Nanofibers Functionalized with Carbon Nanotubes for Electrochemical Detection of Dopamine
The use of nanomaterials as an electroactive
medium has improved
the performance of bio/chemical sensors, particularly when synergy
is reached upon combining distinct materials. In this paper, we report
on a novel architecture comprising electrospun polyamide 6/polyÂ(allylamine
hydrochloride) (PA6/PAH) nanofibers functionalized with multiwalled
carbon nanotubes, used to detect the neurotransmitter dopamine (DA).
Miscibility of PA6 and PAH was sufficient to form a single phase material,
as indicated by thermogravimetric analysis (TGA) and differential
scanning calorimetry (DSC), leading to nanofibers with no beads onto
which the nanotubes could adsorb strongly. Differential pulse voltammetry
was employed with indium tin oxide (ITO) electrodes coated with the
functionalized nanofibers for the selective electrochemical detection
of dopamine (DA), with no interference from uric acid (UA) and ascorbic
acid (AA) that are normally present in biological fluids. The response
was linear for a DA concentration range from 1 to 70 μmol L<sup>–1</sup>, with detection limit of 0.15 μmol L<sup>–1</sup> (S/N = 3). The concepts behind the novel architecture to modify
electrodes can be potentially harnessed in other electrochemical sensors
and biosensors
Information Visualization and Feature Selection Methods Applied to Detect Gliadin in Gluten-Containing Foodstuff with a Microfluidic Electronic Tongue
The
fast growth of celiac disease diagnosis has sparked the production
of gluten-free food and the search for reliable methods to detect
gluten in foodstuff. In this paper, we report on a microfluidic electronic
tongue (e-tongue) capable of detecting trace amounts of gliadin, a
protein of gluten, down to 0.005 mg kg<sup>–1</sup> in ethanol
solutions, and distinguishing between gluten-free and gluten-containing
foodstuff. In some cases, it is even possible to determine whether
gluten-free foodstuff has been contaminated with gliadin. That was
made possible with an e-tongue comprising four sensing units, three
of which made of layer-by-layer (LbL) films of semiconducting polymers
deposited onto gold interdigitated electrodes placed inside microchannels.
Impedance spectroscopy was employed as the principle of detection,
and the electrical capacitance data collected with the e-tongue were
treated with information visualization techniques with feature selection
for optimizing performance. The sensing units are disposable to avoid
cross-contamination as gliadin adsorbs irreversibly onto the LbL films
according to polarization-modulated infrared reflection absorption
spectroscopy (PM-IRRAS) analysis. Small amounts of material are required
to produce the nanostructured films, however, and the e-tongue methodology
is promising for low-cost, reliable detection of gliadin and other
gluten constituents in foodstuff