13 research outputs found
Oligoethylene-Glycol-Functionalized Polyoxythiophenes for Cell Engineering: Syntheses, Characterizations, and Cell Compatibilities
A series of methyl- or benzyl-capped oligoethylene glycol
functionalized
2,5-dibromo-3-oxythiophenes are synthesized and successfully polymerized
by either Grignard metathesis (GRIM) polymerization or reductive coupling
polymerization to yield the corresponding polymers in reasonable yields
and molecular weights with narrow molecular weight distribution. These
synthesized polyoxythiophenes exhibit high electroactivity and stability
in aqueous solution when a potential is applied. Polyoxythiophenes
from different polymerization approaches display different colors
after purification and spectroelectrochemical studies confirm that
the difference of color is from the difference of doping state. Little
cytotoxicity is observed for the polymers by in vitro cell compatibility
assay. NIH3T3 fibroblast cells are well attached and proliferate on
spin-coated films. These results indicate that oligoethylene-glycol-functionalized
polyoxythiophenes are promising candidates as conducting biomatierals
for biomedical and bioengineering applications
Polydioxythiophene Nanodots, Nonowires, Nano-Networks, and Tubular Structures: The Effect of Functional Groups and Temperature in Template-Free Electropolymerization
Various nanostructures, including nanofibers, nanodots, nanonetwork, and nano- to microsize tubes of functionalized poly(3,4-ethylenedioxythiophene) (EDOT) and poly(3,4-propylenedioxythiophene) (ProDOT) are created by using a template-free electropolymerization method on indium–tin–oxide substrates. By investigating conducting polymer nanostructures containing various functional groups prepared at different polymerization temperature, we conclude a synergistic effect of functional groups and temperature on the formation of polymer nanostructures when a template-free electropolymerization method is applied. For unfunctionalized EDOT and ProDOT, or EDOT containing alkyl functional groups, nanofibers and nanoporous structures are usually found. Interesting, when polar functional groups are attached, conducting polymers tend to form nanodots at room temperature while grow tubular structures at low temperature. The relationship between surface properties and their nanostructures is evaluated by contact angle measurements. The capacity and electrochemical impedance spectroscopy measurements were conducted to understand the electrical properties of using these materials as electrodes. The results provide the relationship between the functional groups, nanostructures, and electrical properties. We also discuss the potential restriction of using this method to create nanostructures. The copolymerization of different functionalized EDOTs may cause irregular and unexpected nanostructures, which indicates the complex interaction between different functionalized monomers during the electropolymerization
Surface Engineering of Phenylboronic Acid-Functionalized Poly(3,4-ethylenedioxythiophene) for Fast Responsive and Sensitive Glucose Monitoring
In
this study, we have successfully demonstrated a nanostructured
phenylboronic acid-grafted polyÂ(3,4-ethylenedioxythiophene), polyÂ(EDOT-PBA),
platform for fast and sensitive glucose monitoring. The polyÂ(EDOT-PBA)
films of well-organized tubular nanostructures can be fabricated by
direct electropolymerization without templates. Compared to the smooth
polyÂ(EDOT-PBA), the nanotubular polyÂ(EDOT-PBA) shows enhanced glucose
sensitivity and a different adsorption process of bovine serum albumin
(BSA). Besides, the BSA blocking and low concentration of fructose
and galactose do not affect the sensitivity of this platform. Both
quartz crystal microbalance (QCM) and electrochemical impedance spectroscopy
(EIS) methods are used and compared for glucose monitoring by applying
nanotubular polyÂ(EDOT-PBA) as conductive substrates. Compared to QCM
analysis, EIS has a higher sensitivity to glucose and the detection
limit is about 50 ÎĽM. Besides, the binding with glucose on polyÂ(EDOT-PBA)
is highly reversibly. On the basis of these observations, the nanotubular
polyÂ(EDOT-PBA) has a great potential for enzyme-free electrodes targeting
continuous glucose monitoring applications
High Density of Aligned Nanowire Treated with Polydopamine for Efficient Gene Silencing by siRNA According to Cell Membrane Perturbation
High
aspect ratio nanomaterials, such as vertically aligned silicon nanowire
(SiNW) substrates, are three-dimensional topological features for
cell manipulations. A high density of SiNWs significantly affects
not only cell adhesion and proliferation but also the delivery of
biomolecules to cells. Here, we used polydopamine (PD) that simply
formed a thin coating on various material surfaces by the action of
dopamine as a bioinspired approach. The PD coating not only enhanced
cell adhesion, spreading, and growth but also anchored more siRNA
by adsorption and provided more surface concentration for substrate-mediated
delivery. By comparing plain and SiNW surfaces with the same amount
of loaded siRNA, we quantitatively found that PD coating efficiently
anchored siRNA on the surface, which knocked down the expression of
a specific gene by RNA interference. It was also found that the interaction
of SiNWs with the cell membrane perturbed the lateral diffusion of
lipids in the membrane by fluorescence recovery after photobleaching.
The perturbation was considered to induce the effective delivery of
siRNA into cells and allow the cells to carry out their biological
functions. These results suggest promising applications of PD-coated,
high-density SiNWs as simple, fast, and versatile platforms for transmembrane
delivery of biomolecules
Step-Economical Syntheses of Functional BODIPY-EDOT π‑Conjugated Materials through Direct C–H Arylation
Palladium-catalyzed direct C–H
arylations of 4,4-difluoro-4-bora-3a,4a-diaza-<i>s</i>-indacene
(BODIPY) with 3,4-ethyleneÂdioxythioÂphene
(EDOT) derivatives at relatively low temperature (60 °C) provide
moderate to good yields (47%–72%) of products having potential
applications in fluorescent bioimaging and organic optoelectronics
Nanoscale Analysis of a Functionalized Polythiophene Surface by Adhesion Mapping
Functionalized ethyleneÂdioxyÂthiophene
(EDOT) monomers,
hydroxymethyl EDOT (EDOT-OH), and zwitterionic phosphorylcholine EDOT
(EDOT-PC) were electropolymerized to prepare the homopolymers polyÂ(EDOT-OH)
and polyÂ(EDOT-PC), and mixtures of these monomers were used to produce
the copolymer polyÂ(EDOT-OH)-<i>co</i>-polyÂ(EDOT-PC). Force–extension-curve-based
atomic force microscopy (AFM) was utilized to analyze the surfaces
of the films. The PEDOT-OH film yielded force–extension curves
for short stretching, and the PEDOT-PC film yielded curves for long
stretching. A dendron-modified AFM tip with anthracene groups tethered
at the end resulted in adhesion maps with the highest contrast. The
analytical data for the copolymer films correlated with the corresponding
monomer composition, and the maps revealed that the average size for
the copolymer nanodomains ranged from 10–14 nm. This approach
can be applied to studies aimed at understanding the surface structure
of other relevant polymers and copolymers at the nanoscale level
Detection of SARS-CoV‑2 Spike Protein Using Micropatterned 3D Poly(3,4-Ethylenedioxythiophene) Nanorods Decorated with Gold Nanoparticles
The sensitivity and fabrication process
of the detection platform
are important for developing viral disease diagnosis. Recently, the
outbreak of SARS-CoV-2 compelled us to develop a new detection platform
to control such diseases in the future. We present an electrochemical-based
assay that employs the unique properties of gold nanoparticles (AuNPs)
deposited on 3D carboxyl-functionalized poly(3,4-ethylenedioxythiophene)
(PEDOTAc) nanorods for specific and sensitive detection of SARS-CoV-2
spike protein (S1). The 3D-shaped PEDOTAc nanorods offer an ample
surface area for receptor immobilization grown on indium–tin
oxide surfaces through transfer-printing technology. Characterization
via electrochemical, fluorescence, X-ray photoelectron spectroscopy,
and scanning electron microscopy techniques confirmed the structural
and morphological properties of the AuNPs-decorated PEDOTAc. In contrast
to antibody-based assays, our platform employs ACE2 receptors for
spike protein binding. Differential pulse voltammetry records current
responses, showing linear sensitivity from 100 ng to 10 pg/mL of S1.
In addition, the SARS-CoV-2 assay (CoVPNs) also exhibited excellent
selectivity against nonspecific target proteins (H9N2, IL-6, and Escherichia coli). Furthermore, the developed surface maintained
good stability for up to 7 consecutive days without losing performance.
The results provide new insight into effective 3D conductive nanostructure
formation, which is promising in the development of versatile sensory
devices
Electropolymerized Conjugated Polyelectrolytes with Tunable Work Function and Hydrophobicity as an Anode Buffer in Organic Optoelectronics
A new class of conductive polyelectrolyte films with
tunable work
function and hydrophobicity has been developed for the anode buffer
layer in organic electronic devices. The work function of these films
featuring a copolymer of ethylenedioxythiophene (EDOT), and its functionalized
analogues were found to be easily tunable over a range of almost 1
eV and reach values as high as those of PEDOT:PSS. The new buffer
material does not need the addition of any insulating or acidic material
that might limit the film conductivity or device lifetime. Organic
photovoltaic devices built with these films showed improved open-circuit
voltage over those of the known PSS-free conductive EDOT-based polymers
with values as high as that obtained for PEDOT:PSS. Furthermore, the
surface hydrophobicity of these new copolymer films was found to be
sensitive to the chemical groups attached to the polymer backbone,
offering an attractive method for surface energy tuning
Controlled Protein Absorption and Cell Adhesion on Polymer-Brush-Grafted Poly(3,4-ethylenedioxythiophene) Films
Tailoring the surface of biometallic
implants with protein-resistant polymer brushes represents an efficient
approach to improve the biocompability and mechanical compliance with
soft human tissues. A general approach utilizing electropolymerization
to form initiating group (-Br) containing polyÂ(3,4-ethylenedioxythiophen)Âs
(polyÂ(EDOT)Âs) is described. After the conducting polymer is deposited,
neutral polyÂ((oligoÂ(ethylene glycol) methacrylate), polyÂ(OEGMA), and
zwitterionic polyÂ([2-(methacryloyloxy)Âethyl]Âdimethyl-(3-sulfopropyl)Âammonium
hydroxide), polyÂ(SBMA), brushes are grafted by surface-initiated atom
transfer radical polymerization. Quartz crystal microbalance (QCM)
experiments confirm protein resistance of polyÂ(OEGMA) and polyÂ(SBMA)-grafted
polyÂ(EDOT)Âs. The protein binding properties of the surface are modulated
by the density of polymer brushes, which is controlled by the feed
content of initiator-containing monomer (EDOT-Br) in the monomer mixture
solution for electropolymerization. Furthermore, these polymer-grafted
polyÂ(EDOT)Âs also prevent cells to adhere on the surface
Facile Syntheses of Dioxythiophene-Based Conjugated Polymers by Direct C–H Arylation
Various substituted dioxythiophenes bearing 3,4-propylenedioxythiophenes
(ProDOT) and 3,4-ethylenedioxythiophene (EDOT) moieties successfully
undergo Pd-catalyzed direct C–H arylation to yield π-conjugated
polymers. The effects of palladium catalysts, phosphine ligands or
additives, and functional groups on this facile polycondensation approach
are investigated. Polymers from alkoxy-substituted ProDOT are synthesized
with reasonable molecular weight (<i>M</i><sub>n</sub> =
6100–9600) and low PDI (1.3–1.9). Four substituted EDOT
with alkoxy or protected functional groups also undergo direct C–H
arylation polycondensation to yield corresponding polymers. The obtained
polydioxythiophenes exhibit UV–vis absorptions ranging from
480 to 590 nm, and these conjugated polymers are electroactive and
reversibly switched between the oxidized and neutral states upon applying
potentials