11 research outputs found
Poly(4-vinylaniline)/polyaniline bilayer functionalized bacterial cellulose membranes as bioelectronics interfaces
Bacterial cellulose (BC) fibers are chemically functionalized with poly(4-vinylaniline) (PVAN) interlayer for further enhancement of electrical conductivity and cell viability of polyaniline (PANI) coated BC nanocomposites. PVAN is found to have promoted the formation of a uniform PANI layer with nanofiber- and nanorod-like supramolecular structures, as an overall augmentation of PANI yield. Compositional and microstructural analysis indicates a PVAN/PANI bilayer of approximately 2 ÎŒm formed on BC. The solid-state electrical conductivity of such synthesized BC nanocomposites can be as high as (4.5 ± 1.7) Ă 10â2 S cmâ1 subject to the amounts of PVAN chemically embraced. BC/PVAN/PANI nanocomposites are confirmed to be thermally stable up to 225 °C, and no signs of cytotoxicity for SVZ neural stem cells are detected, with cell viability up to 90% on BC/PVAN/PANI membranes. We envisage these new electrically conductive BC/PVAN/PANI nanocomposites can potentially enable various biomedical applications, such as for the fabrication of bioelectronic interfaces and biosensors
Electrochemical Deposition of CoP and CoNiP as Hard Magnetic Scales in a Position Measurement System
The fabrication and design of hard magnetic materials for micro-electro-mechanical system applications by electrochemical deposition has to consider not only the intrinsic material properties but also the shape anisotropy of the micro-devices. Within the scope of the present work, an as-plated process for hard magnetic Co-based materials was developed, with the products intended to be used as magnetic scales in a positioning system with a resolution within the nanometer range. First, the process–material correlations are investigated in a laboratory-scale process. The CoP and CoNiP show a maximum coercivity of HC = 28 and 45 kA/m, respectively, as well as maximum remanence polarizations of JR = 0.65 and 0.40 T, respectively. The CoP process is transferred to a specially developed 20 L plating cell with paddle convection capabilities and a passive bezel to deposit 50 µm wide scales with different thicknesses of up to 55 µm in an integrated process. The in-plane magnetization of the scale bars shows higher remanence polarization than for the out-of-plane direction. Magnetic field-assisted electrochemical deposition promotes the vertical magnetization component resulting in a remanence polarization of 205 mT (out-of-plane) for a scale thickness of 25 µm
Biegeverformung und EindringhÀrte von Mikroproben aus elektrochemisch abgeschiedenen nanokristallinen Nickel-Eisen-Legierungen
Advanced Biomimetic Nanostructured Microelectrode Arrays for Enhanced Extracellular Recordings of Enteric Neurons
Abstract Microelectrode surfaces covered with nanostructures derived from components of extracellular matrix, such as collagen fibers, have shown immense beneficial effects in promoting neuronal growth and cellular signaling. Synthetic nanostructures mimicking the features of biological nanostructures with durable conductive materials could promote the cell adhesion on microelectrode surfaces by providing topographical cues and simultaneously improve the charge transfer properties by reducing its global impedance. Therefore, an advanced nanostructuring method mimicking the structural and organizational features of natural collagen fibers onto metallic microelectrode surfaces has been presented here, which is adapted from previous technological achievements of the group and is based on nanoimprint lithography and gold electroplating. Surface characterization methods reveal an increase in surface area between 20% and 68% on the microelectrodes fabricated with two different nanostructure heights. Impedance spectroscopy measurements reveal reduction in impedance magnitude (at 1Â kHz) between 22% and 41%, depending upon the nanostructure height and density on the microelectrode, which should subsequently modulate its charge transfer properties for biosensing application. Cell adhesion analysis performed with seal impedance measurements reveals a tighter coupling of enteric neurons on the nanostructured microelectrodes. Finally, extracellular recordings from enteric neurons exhibit a significant improvement in spike detection properties of the nanostructured microelectrodes
Carbon Nanotube-Reinforced Poly(4-vinylaniline)/Polyaniline Bilayer-Grafted Bacterial Cellulose for Bioelectronic Applications
This paper is in closed access.Microbial cellulose paper treated with polyaniline and carbon nanotubes (PANI/CNTs) can be attractive as
potential flexible capacitors in terms of further improvements
to the conductivity and thermal resistance. The interactions
between PANI and CNTs exhibit new electrochemical features
with increased electrical conductivity and enhanced capacity.
In this study, PANI/CNTs was incorporated into a flexible
poly(4-vinylaniline)-grafted bacterial cellulose (BC/PVAN)
nanocomposite substrate for further functionalization and
processability. PANI/CNTs coatings with a nanorod-like
structure can promote an efficient ion diffusion and charge
transfer, with a significant enhancement of the electrical
conductivity after CNTs reinforcement of 1 order of
magnitude up to (1.0 ± 0.3) Ă 10â1 S·cmâ1
. An escalating
improvement of the double charge capacity (âŒ54 mF) of the grafted BC nanocomposites was also detected through
electrochemical analysis. The multilayered electrical coatings also reinforce the thermal resistance, preventing anticipated
thermal degradation of the BC substrate. The cell viability and differentiation assays using neural stem cells (SVZ cells) testified
to the cytocompatibility of the grafted BC nanocomposites, while inducing neuronal differentiation over 7 days of culture with a
neurite that was 77 ± 24.7 Όm long. This is promising for meeting the requirements in the construction of high-performance
bioelectronic devices that can actively interface biologically, providing a friendly environment for cells while tuning the device
performance
Fabrication and characterization of Cu-Sn-Ni-Cu interconnection microstructure for electromigration studies in 3D integration
Mechanical behavior of annealed electrochemically deposited nanocrystalline nickel-iron alloys
Carbon nanotube-reinforced poly(4-vinylaniline)/polyaniline bilayer-grafted bacterial cellulose for bioelectronic applications
Microbial cellulose paper treated with polyaniline and carbon nanotubes (PANI/CNTs) can be attractive as
potential flexible capacitors in terms of further improvements
to the conductivity and thermal resistance. The interactions
between PANI and CNTs exhibit new electrochemical features
with increased electrical conductivity and enhanced capacity.
In this study, PANI/CNTs was incorporated into a flexible
poly(4-vinylaniline)-grafted bacterial cellulose (BC/PVAN)
nanocomposite substrate for further functionalization and
processability. PANI/CNTs coatings with a nanorod-like
structure can promote an efficient ion diffusion and charge
transfer, with a significant enhancement of the electrical
conductivity after CNTs reinforcement of 1 order of
magnitude up to (1.0 ± 0.3) Ă 10â1 S·cmâ1
. An escalating
improvement of the double charge capacity (âŒ54 mF) of the grafted BC nanocomposites was also detected through
electrochemical analysis. The multilayered electrical coatings also reinforce the thermal resistance, preventing anticipated
thermal degradation of the BC substrate. The cell viability and differentiation assays using neural stem cells (SVZ cells) testified
to the cytocompatibility of the grafted BC nanocomposites, while inducing neuronal differentiation over 7 days of culture with a
neurite that was 77 ± 24.7 Όm long. This is promising for meeting the requirements in the construction of high-performance
bioelectronic devices that can actively interface biologically, providing a friendly environment for cells while tuning the device
performance
Poly(4-vinylaniline)/polyaniline bilayer functionalized bacterial cellulose for flexible electrochemical biosensors
Bacterial cellulose (BC) nanofibril network is modified with an electrically conductive
polyvinylaniline/polyaniline (PVAN/PANI) bilayer for construction of potential
electrochemical biosensors. This is accomplished through surface-initiated atom transfer
radical polymerization of 4-vinylaniline, followed by in situ chemical oxidative
polymerization of aniline. A uniform coverage of BC nanofiber with 1D supramolecular
PANI nanostructures is confirmed by FTIR, XRD and CHN elemental analysis. Cyclic
voltammograms evince the switching in the electrochemical behavior of BC/PVAN/PANI nanocomposites from the redox peaks at 0.74 V, in the positive scan
and at -0.70 V, in the reverse scan, (at 100 mV.s-1
scan rate). From these redox peaks,
PANI is the emeraldine form with the maximal electrical performance recorded,
showing charge-transfer resistance as low as 21 Ω and capacitance as high as 39 ΌF.
The voltage-sensible nanocomposites can interact with neural stem cells (NSCs)
isolated from subventricular zone (SVZ) of the brain, through stimulation and
characterization of differentiated SVZ cells into specialized and mature neurons with
long neurites measuring up to 115±24 Όm length after 7 days of culture without visible
signs of cytotoxic effects. The findings pave the path to the new effective nanobiosensor
technologies for nerve regenerative medicine, which demands both electroactivity and
biocompatibility