Three-Dimensional BC/PEDOT Composite Nanofibers with High Performance for Electrode-Cell Interface

Magnetic Induction Heating in a Conducting Polymer for Biomedical Applications

In this study, we investigate the magnetic induction heating induced in a conducting polymer (CP) under alternative magnetic fields (AMFs). Experimental results and numerical simulations have proved that the magneto-thermal conversion of the CP is caused by the induced eddy current, which is related to the shape and intensity of the applied external AMF, and the intrinsic electrical conductivity, macrostructure and microstructure of the CP. By employing various fabrication methods, specific temperature distribution and control of thermal field within conducting polymer films and aerogels could be achieved. To exploit the potential of magnetic induction heating in CP for biomedical applications, we designed a conducting polymer aerogel-based self-adaptive heat patch and demonstrated its AMF-enabled localized heating of skin. In addition to the thermal ablation of tumor cells via magneto-thermal conversion of the CP, the promotion of neuronal differentiation at mild temperature by noninvasive magneto-electrical stimulation has also been demonstrated to be an effective strategy for tissue engineering.

Three-Dimensional Sulfated Bacterial Cellulose/Gelatin Composite Scaffolds for Culturing Hepatocytes

The liver is the hub of human metabolism and involves many diseases. To better work on the mechanism and treatment of liver diseases, it is of particular interest to design 3-dimensional scaffolds suitable for culturing hepatocytes in vitro to simulate their metabolic and regenerative abilities. In this study, sulfated bacterial cellulose (SBC) was prepared as the building block of cell scaffolds, motivated by the anionic nature and 3-dimensional structure of hepatic extracellular matrix, and its reaction condition for sulfate esterification was optimized by changing the reaction time. The analysis and study of the microscopic morphology, structure, and cytocompatibility of SBCs showed that they possess good biocompatibility and meet the requirements for tissue engineering. Next, SBC was mixed with gelatin for composite scaffolds (SBC/Gel) for culturing hepatocytes by homogenization and freeze-drying methods, whose physical properties such as pore size, porosity, and compression properties were compared with gelatin (Gel) scaffolds as the control group, and the cytological activity and hemocompatibility of the composite scaffolds were investigated. The results showed that the SBC/Gel composite has better porosity and compression properties, as well as good cytocompatibility and hemocompatibility, and could be applied to 3-dimensional culture of hepatocytes for drug screening or liver tissue engineering.

Conductive and Adhesive Granular Alginate Hydrogels for On-Tissue Writable Bioelectronics

Conductive hydrogels are promising materials in bioelectronics that ensure a tissue-like soft modulus and re-enact the electrophysiological function of damaged tissues. However, recent approaches to fabricating conductive hydrogels have proved difficult: fixing of the conductive hydrogels on the target tissues hydrogels requires the aids from other medical glues because of their weak tissue-adhesiveness. In this study, an intrinsically conductive and tissue-adhesive granular hydrogel consisting of a PEDOT:PSS conducting polymer and an adhesive catechol-conjugated alginate polymer was fabricated via an electrohydrodynamic spraying method. Because alginate-based polymers can be crosslinked by calcium ions, alginate-catechol polymers mixed with PEDOT:PSS granular hydrogels (ACP) were easily fabricated. The fabricated ACP exhibited not only adhesive and shear-thinning properties but also conductivity similar to that of muscle tissue. Additionally, the granular structure makes the hydrogel injectable through a syringe, enabling on-tissue printing. This multifunctional granular hydrogel can be applied to soft and flexible electronics to connect humans and machines.

Effects of Electrical Stimulation on Articular Cartilage Regeneration with a Focus on Piezoelectric Biomaterials for Articular Cartilage Tissue Repair and Engineering

There is increasing evidence that chondrocytes within articular cartilage are affected by endogenous force-related electrical potentials. Furthermore, electrical stimulation (ES) promotes the proliferation of chondrocytes and the synthesis of extracellular matrix (ECM) molecules, which accelerate the healing of cartilage defects. These findings suggest the potential application of ES in cartilage repair. In this review, we summarize the pathogenesis of articular cartilage injuries and the current clinical strategies for the treatment of articular cartilage injuries. We then focus on the application of ES in the repair of articular cartilage in vivo. The ES-induced chondrogenic differentiation of mesenchymal stem cells (MSCs) and its potential regulatory mechanism are discussed in detail. In addition, we discuss the potential of applying piezoelectric materials in the process of constructing engineering articular cartilage, highlighting the important advances in the unique field of tissue engineering.

Bacterial cellulose-based biomaterials: From fabrication to application

Driven by its excellent physical and chemical properties, BC (bacterial cellulose) has achieved significant progress in the last decade, rendering with many novel applications. Due to its resemblance to the structure of extracellular matrix, BC-based biomaterials have been widely explored for biomedical applications such as tissue engineering and drug delivery. The recent advances in nanotechnology endow further modifications on BC and generate BC-based composites for different applications. This article presents a review on the research advancement on BC-based biomaterials from fabrication methods to biomedical applications, including wound dressing, artificial skin, vascular tissue engineering, bone tissue regeneration, drug delivery, and other applications. The preparation of these materials and their potential applications are reviewed and summarized. Important factors for the applications of BC in biomedical applications including degradation and pore structure characteristic are discussed in detail. Finally, the challenges in future development and potential advances of these materials are also discussed.

Electrical Stimulation Promotes Stem Cell Neural Differentiation in Tissue Engineering

Nerve injuries and neurodegenerative disorders remain serious challenges, owing to the poor treatment outcomes of in situ neural stem cell regeneration. The most promising treatment for such injuries and disorders is stem cell-based therapies, but there remain obstacles in controlling the differentiation of stem cells into fully functional neuronal cells. Various biochemical and physical approaches have been explored to improve stem cell-based neural tissue engineering, among which electrical stimulation has been validated as a promising one both in vitro and in vivo. Here, we summarize the most basic waveforms of electrical stimulation and the conductive materials used for the fabrication of electroactive substrates or scaffolds in neural tissue engineering. Various intensities and patterns of electrical current result in different biological effects, such as enhancing the proliferation, migration, and differentiation of stem cells into neural cells. Moreover, conductive materials can be used in delivering electrical stimulation to manipulate the migration and differentiation of stem cells and the outgrowth of neurites on two- and three-dimensional scaffolds. Finally, we also discuss the possible mechanisms in enhancing stem cell neural differentiation using electrical stimulation. We believe that stem cell-based therapies using biocompatible conductive scaffolds under electrical stimulation and biochemical induction are promising for neural regeneration.

Vapor phase polymerization for electronically conductive nanopaper based on bacterial cellulose/poly(3,4-ethylenedioxythiophene)

Eco-friendly conductive polymer nanocomposites have garnered attention as an effective alternative for conventional conductive nanocomposites. Here, we report the fabrication and optimization of flexible, self-standing, and conductive bacterial cellulose/poly(3,4-ethylene dioxythiophene) (BC/PEDOT) nanocomposites using the vapor phase polymerization (VPP) method. Eco-friendly bacterial cellulose (BC) is used as a flexible matrix, and the highly conductive PEDOT polymer is introduced into the BC matrix to achieve electronic conductivity. We demonstrate that vapor phase polymerized BC/PEDOT composites exhibit more than 10 times lower sheet resistance (18 Ω/square) compared to solution polymerized BC/PEDOT (188 Ω/square). The resultant BC/PEDOT fabricated could be bent up to 100 times and completely rolled up without a notable decrease in electronic performance. Moreover, bent BC/PEDOT films enable operation of a green light-emitting diode (LED) light, indicating the flexibility and stability of conductive BC/PEDOT films. Overall, this study suggests a strategy for the development of eco-friendly, flexible, and conductive nanocomposite films.

Transparent Conductive Silk Film with a PEDOT-OH Nano Layer as an Electroactive Cell Interface

Bioelectronics based on biomaterial substrates are advancing toward biomedical applications. As excellent conductors, poly(3,4-ethylenedioxythiophene) (PEDOT) and its derivatives have been widely developed in this field. However, it is still a big challenge to obtain a functional layer with a good electroconductive property, transparency, and strong adhesion on the biosubstrate. In this work, poly(hydroxymethyl-3,4-ethylenedioxythiophene) (PEDOT-OH) was chemically polymerized and deposited on the surface of a regenerated silk fibroin (RSF) film in an aqueous system. Sodium dodecyl sulfate (SDS) was used as the surfactant to form micelles which are beneficial to the polymer structure. To overcome the trade-off between transparency and the electroconductive property of the PEDOT-OH coating, a composite oxidant recipe of FeCl₃ and ammonium persulfate (APS) was developed. Through electrostatic interaction of oppositely charged doping ions, a well-organized conductive nanoscale coating formed and a transparent conductive RSF/PEDOT-OH film was produced, which can hardly be achieved in a traditional single oxidant system. The produced film had a sheet resistance (R_s) of 5.12 × 10⁴ Ω/square corresponding to a conductivity of 8.9 × 10^-2 S/cm and a maximum transmittance above 73% in the visible range. In addition, strong adhesion between PEDOT-OH and RSF and favorable electrochemical stability of the film were demonstrated. Desirable transparency of the film allowed real-time observation of live cells. Furthermore, the PEDOT-OH layer provided an improved environment for adhesion and differentiation of PC12 cells compared to the RSF surface alone. Finally, the feasibility of using the RSF/PEDOT-OH film to electrically stimulate PC12 cells was demonstrated.

Electrical percolation in extrinsically conducting, poly(ε-decalactone) composite neural interface materials

By providing a bidirectional communication channel between neural tissues and a biomedical device, it is envisaged that neural interfaces will be fundamental in the future diagnosis and treatment of neurological disorders. Due to the mechanical mismatch between neural tissue and metallic neural electrodes, soft electrically conducting materials are of great benefit in promoting chronic device functionality. In this study, carbon nanotubes (CNT), silver nanowires (AgNW) and poly(hydroxymethyl 3,4-ethylenedioxythiophene) microspheres (MSP) were employed as conducting fillers within a poly(ε-decalactone) (EDL) matrix, to form a soft and electrically conducting composite. The effect of a filler type on the electrical percolation threshold, and composite biocompatibility was investigated in vitro. EDL-based composites exhibited favourable electrochemical characteristics: EDL/CNT-the lowest film resistance (1.2 ± 0.3 kΩ), EDL/AgNW-the highest charge storage capacity (10.7 ± 0.3 mC cm- 2), and EDL/MSP-the highest interphase capacitance (1478.4 ± 92.4 µF cm-2). All investigated composite surfaces were found to be biocompatible, and to reduce the presence of reactive astrocytes relative to control electrodes. The results of this work clearly demonstrated the ability of high aspect ratio structures to form an extended percolation network within a polyester matrix, resulting in the formulation of composites with advantageous mechanical, electrochemical and biocompatibility properties.

Oscillating Magnetic Field Regulates Cell Adherence and Endothelialization Based on Magnetic Nanoparticle-Modified Bacterial Cellulose

Despite the widely explored biomaterial scaffolds in vascular tissue engineering applications lately, no ideal platform has been provided for small diameter synthetic vascular grafts mainly due to the thrombosis issue. Endothelium is the only known completely non-thrombogenic material; so, functional endothelialization onto vascular biomaterials is critical in maintaining the patency of vascular networks. Bacterial cellulose (BC) is a natural biomaterial with superior biocompatibility and appropriate hydrophilicity as potential vascular grafts. In previous studies, surface modification of active peptides such as Arg-Gly-Asp (RGD) sequences onto biomaterials has been proven to achieve accelerated and selective endothelial cell (EC) adhesion. In our study, we demonstrated a new strategy to remotely regulate the adhesion of endothelial cells based on an oscillating magnetic field and achieve successful endothelialization on the modified BC membranes. In details, we synthesized bacterial cellulose (BC), magnetic BC (MBC), and RGD peptide-grafted magnetic BC (RMBC), modified with the HOOC-PEG-COOH-coated iron oxide nanoparticles (PEG-IONs). The endothelial cells were cultured on the three materials under different frequencies of an oscillating magnetic field, including "stationary" (0 Hz), "slow" (0.1 Hz), and "fast" (2 Hz) groups. Compared to BC and MBC membranes, the cells on RMBC membranes generally show better adhesion and proliferation. Meanwhile, the "slow" frequency of a magnetic field promotes this phenomenon on RMBC and achieves endothelialization after culture for 4 days, whereas "fast" inhibits the cellular attachment. Overall, we demonstrate a non-invasive and convenient method to regulate the endothelialization process, with promising applications in vascular tissue engineering.

Effect of conducting/thermoresponsive polymer ratio on multitasking nanogels

Semi-interpenetrated nanogels (NGs) able to release and sense diclofenac (DIC) have been designed to act as photothermal agents with the possibility to ablate cancer cells using mild-temperatures (<45 °C). Combining mild heat treatments with simultaneous chemotherapy appears as a very promising therapeutic strategy to avoid heat resistance or damaging the surrounding tissues. Particularly, NGs consisted on a poly(N-isopropylacrylamide) (PNIPAM) and dendritic polyglycerol (dPG) mesh containing a semi-interpenetrating network (SIPN) of poly(hydroxymethyl 3,4-ethylenedioxythiophene) (PHMeEDOT). The PHMeEDOT acted as photothermal and conducting agent, while PNIPAM-dPG NG provided thermoresponsivity and acted as stabilizer. We studied how semi-interpenetration modified the physicochemical characteristics of the thermoresponsive SIPN NGs and selected the best condition to generate a multifunctional photothermal agent. The thermoswitchable conductiveness of the multifunctional NGs and the redox activity of DIC could be utilized for its electrochemical detection. Besides, as proof of the therapeutic concept, we investigated the combinatorial effect of photothermal therapy (PTT) and DIC treatment using the HeLa cancer cell line in vitro. Within 15 min NIR irradiation without surpassing 45 °C we were able to kill 95% of the cells, demonstrating the potential of SIPN NGs as drug carriers, sensors and agents for mild PTT.

Improved Hydrophobicity of a Bacterial Cellulose Surface: Click Chemistry in Action

The vast application potentials of bacterial cellulose (BC)-based materials for developing leather-like materials, wound-healing materials and electronic materials have been realized very recently. Surface functionalization of these materials can help in improvement of certain properties such as water repellency, mechanical strength, and so forth. In this paper, we reported functionalization of BC surfaces using "click" polymerization for the first time. By this methodology, dense aromatic groups have been incorporated for the improvement of hydrophobicity. For comparative studies, various fluorine-based compounds have been introduced using conventional click reactions. The surface-modified BC materials have been confirmed by various spectroscopic methods. Particularly, the chemical structures of the materials were studied by solid-state ¹³C NMR spectroscopy and attenuated total reflection-infrared spectroscopy. X-ray photoelectron spectroscopy was used to study the elemental composition of the materials. Moreover, the crystallite changes of modified BC surfaces were investigated by X-ray diffraction. Further, the changes in the morphology of the material after functionalization were evaluated by scanning electron microscopy and atomic force microscopy. Finally, water contact angle measurement revealed manyfold increase in hydrophobicity after click polymerization. A video is also provided in the Supporting Information to show the application potential of this material for developing leather-like materials.

Controlling the degradation of cellulose scaffolds with Malaprade oxidation for tissue engineering

Cellulose scaffolds, whose biodegradation can be controlled through the reaction with amine compounds in the human body, were developed for tissue engineering applications.

Injectable and Conductive Granular Hydrogels for 3D Printing and Electroactive Tissue Support

Conductive hydrogels are attractive to mimic electrophysiological environments of biological tissues and toward therapeutic applications. Injectable and conductive hydrogels are of particular interest for applications in 3D printing or for direct injection into tissues; however, current approaches to add conductivity to hydrogels are insufficient, leading to poor gelation, brittle properties, or insufficient conductivity. Here, an approach is developed using the jamming of microgels to form injectable granular hydrogels, where i) hydrogel microparticles (i.e., microgels) are formed with water-in-oil emulsions on microfluidics, ii) microgels are modified via an in situ metal reduction process, and iii) the microgels are jammed into a solid, permitting easy extrusion from a syringe. Due to the presence of metal nanoparticles at the jammed interface with high surface area in this unique design, the granular hydrogels have greater conductivity than non-particle (i.e., bulk) hydrogels treated similarly or granular hydrogels either without metal nanoparticles or containing encapsulated nanoparticles. The conductivity of the granular hydrogels is easily modified through mixing conductive and non-conductive microgels during fabrication and they can be applied to the 3D printing of lattices and to bridge muscle defects. The versatility of this conductive granular hydrogel will permit numerous applications where conductive materials are needed.

Highly dispersive NiCo2S4 nanoparticles anchored on nitrogen-doped carbon nanofibers for efficient hydrogen evolution reaction

To solve the energy crisis problem, many efforts have been devoted to develop clean and sustainable alternatives to fossil fuels. Among varieties of pathways to obtain clean energy, electrochemical water splitting is a promising approach. Herein, we had successfully synthesized the NiCo₂S₄@porous nitrogen-doped carbon nanofibers (NiCo₂S₄@NCNF) nanocomposite via three successive steps consisted of in-situ oxidative polymerization, calcination, and solvothermal sulfuration reaction processes. The effect of controlled molar ratios to electrocatalytic performance was studied in detail. The optimized NiCo₂S₄@NCNF nanocomposite exhibits superior electrocatalytic activity for hydrogen evolution reaction with a small overpotential of 117 mV to drive a current density of 10 mA cm^-2. More importantly, it exhibits similar electrocatalytic activity to the initial state even after successive cyclic voltammetry scan for 3000 cycles, indicating its excellent long-term stability. The superior electrochemical performance is attributed to the developed three-dimensional (3D) network nanostructure derived from bacterial cellulose nanofibers, the highly conductive porous nitrogen-doped carbon nanofibers, and the synergistic effect between metal Ni and Co of NiCo₂S₄. This study permits a new pathway to design efficient electrocatalysts based on eco-friendly materials for the production of clean hydrogen energy.

Cellulose Biomaterials for Tissue Engineering

In this review, we highlight the importance of nanostructure of cellulose-based biomaterials to allow cellular adhesion, the contribution of nanostructure to macroscale mechanical properties, and several key applications of these materials for fundamental scientific research and biomedical engineering. Different features on the nanoscale can have macroscale impacts on tissue function. Cellulose is a diverse material with tunable properties and is a promising platform for biomaterial development and tissue engineering. Cellulose-based biomaterials offer some important advantages over conventional synthetic materials. Here we provide an up-to-date summary of the status of the field of cellulose-based biomaterials in the context of bottom-up approaches for tissue engineering. We anticipate that cellulose-based material research will continue to expand because of the diversity and versatility of biochemical and biophysical characteristics highlighted in this review.

Study of Electrical Stimulation with Different Electric-Field Intensities in the Regulation of the Differentiation of PC12 Cells

The strategy of using electrical stimulation (ES) to promote the neural differentiation and regeneration of injured nerves is proven feasible. Study of the possible molecular mechanisms in relation to this ES promotion effect should be helpful for understanding the phenomenon. In this study, it was identified that the neuronal differentiation of PC12 cells was enhanced when the electric field intensity was in the range of 30-80 mV/mm, and a lower or higher electric-field intensity displayed inferior effects. Under ES, however, levels of intracellular reactive oxygen species (ROS), intracellular Ca²⁺ dynamics, and expression of TREK-1 were measured as being gradually increasing alongside higher electric-field intensity. In trying to understand the relationship between the ES enhancement on differentiation and these variations in cell activities, parallel experiments were conducted by introducing exogeneous H₂O₂ into culture systems at different concentrations. Similarly, the effects of H₂O₂ concentration on the neuronal differentiation of PC12 cells, intracellular ROS and Ca²⁺ levels, and TREK-1 expression were systematically characterized. In comparative studies, it was found in two cases that ES of 50 mV/mm for 2 h/day and H₂O₂ of 5 μM in culture medium shared comparable results for intracellular ROS and Ca²⁺ levels and TREK-1 expression. Higher H₂O₂ concentrations (e.g., 10 and 20 μM) demonstrated adverse effects on cell differentiation and caused DNA damage. A stronger ES (e.g., 100 mV/mm), being associated with a higher intracellular ROS level, also resulted in weaker enhancement of the neuronal differentiation of PC12 cells. These facts suggested that the intracellular ROS generated under ES might be an intermediate signal transducer involved in cascade reactions relative to cell differentiation.

Immobilization of quaternized polymers on bacterial cellulose by different grafting techniques

Different polymers were immobilized on bacterial cellulose surfaces using grafting techniques to improve their mechanical properties and surface hydrophobicity.

Bacterial Cellulose as a Supersoft Neural Interfacing Substrate

Biocompatible neural interfaces hold great promise for treating neurological disorders and enhancing the mental and physical ability of human beings. Most of the currently available neural interfaces are made from rigid, dense inorganic materials that cause tissue damage. We present supersoft multichannel electrodes by depositing gold layers on thin bacterial cellulose (BC) (Au-BC electrodes). The Young's modulus of BC ( E_BC = 120 kPa) is between those of the brain tissue ( E_brain = 2.7-3.1 kPa) and the peripheral neural tissues ( E_{peripheral nerve} = 580-840 kPa). The bending stiffness of the Au-BC electrodes corresponds to 1/5200 of Au-polyimide electrodes with the same layout. Furthermore, the Au-BC electrodes are highly durable (conductivity >95% after 100 cycles of 180° bending). In vivo recording of brain electric activity demonstrates the great potential of the Au-BC electrodes for neural interfacing applications.

A PDMS-based optical waveguide for transcutaneous powering of microelectrode arrays

Implantable microelectrode arrays (MEAs) usually have on-site electronics that need to be powered, both in neural recording and stimulation applications. Interconnecting wires between implanted electrodes and the outside world constitute a major source of complications. Our solution to this tethering problem is to design a light waveguide that can collect the optical power transcutaneously and transmit it to the microelectrode array where it is to be converted to an electric current. A polydimethylsiloxane (PDMS)-based waveguide was fabricated and its attenuation was measured in vitro and found to be 0.36 dB/cm. The skin flap of the thenar web space in the hand was used to test the photon collection efficiency of the waveguide in diffuse light. The efficiency of the waveguide alone was 44±11% (mean±std), excluding the attenuation within the thenar skin, as measured in 13 subjects with different skin pigmentations. These preliminary results suggest that a PDMS waveguide may collect and deliver optical power with sufficient efficiencies to deep structures inside the body. Optical powering scheme can solve the tethering and breakage problems associated with metal wire connections.

Electrically-responsive core-shell hybrid microfibers for controlled drug release and cell culture

It is an active research field to develop fiber-shaped smart materials for biomedical applications. Here we report the development of the multifunctional core-shell hybrid microfibers with excellent mechanical and electrical performance as a new smart biomaterial. The microfibers were synthesized using a combination of co-axial spinning with a microfluidic device and subsequent dip-coating, containing a hydrogel core of bacterial cellulose (BC) and a conductive polymer shell layer of poly(3,4-ethylenedioxythiophene) (PEDOT). The hybrid microfibers were featured with a well-controlled microscopic morphology, exhibiting enhanced mechanic properties. A model drug, diclofenac sodium, can be loaded in the core layer of the microfibers in situ during the process of synthesis. Our experiments suggested that the releasing behaviors of the drug molecules from the microfibers were enhanced by external electrical stimulation. Interestingly, we demonstrated an excellent biocompatibility and electroactivity of the hybrid microfibers for PC12 cell culture, thus promising a flexible template for the reconstruction of electrically-responsive tissues mimicking muscle fibers or nerve networks.

STATEMENT OF SIGNIFICANCE

Fiber-shaped biomaterials are useful in creating various functional objects from one dimensional to three-dimensional. The fabrication of microfibers with integrated physicochemical properties and bio-performance has drawn an increasing attention on researchers from chemical to biomedical. This study combined biocompatible bacterial cellulose with electroconductive poly(3,4-ethylenedioxythiophene) and further reduced them to a highly electroactive BC/PEDOT core-shell microfiber electrode for electrochemical actuator design. The result showed that the microfibers were well fabricated and the release of drugs from the microfibers was enhanced and could be controlled under electrical stimulation externally. Considering the excellent biocompatibility and electroactive toward PC12 cells, these microfibers may find use as templates for the reconstruction of fiber-shaped functional tissues that mimic muscle fibers, blood vessels or nerve networks in vivo.

Polyhydroxyalkanoate/carbon nanotube nanocomposites: flexible electrically conducting elastomers for neural applications

Aim: Medium chain length-polyhydroxyalkanoate/multi-walled carbon nanotube (MWCNTs) nanocomposites with a range of mechanical and electrochemical properties were fabricated via assisted dispersion and solvent casting, and their suitability as neural interface biomaterials was investigated. Materials & methods: Mechanical and electrical properties of medium chain length-polyhydroxyalkanoate/MWCNTs nanocomposite films were evaluated by tensile test and electrical impedance spectroscopy, respectively. Primary rat mesencephalic cells were seeded on the composites and quantitative immunostaining of relevant neural biomarkers, and electrical stimulation studies were performed. Results: Incorporation of MWCNTs to the polymeric matrix modulated the mechanical and electrical properties of resulting composites, and promoted differential cell viability, morphology and function as a function of MWCNT concentration. Conclusion: This study demonstrates the feasibility of a green thermoplastic MWCNTs nanocomposite for potential use in neural interfacing applications.

Biointerface by Cell Growth on Graphene Oxide Doped Bacterial Cellulose/Poly(3,4-ethylenedioxythiophene) Nanofibers

Highly biocompatible advanced materials with excellent electroactivity are increasingly meaningful to biointerfaces and the development of biomedicine. Herein, bacterial cellulose/poly(3,4-ethylene dioxythiophene)/graphene oxide (BC/PEDOT/GO) composite nanofibers were synthesized through the in situ interfacial polymerization of PEDOT with the doping of GO. The abundant free carboxyl and hydroxy groups offer the BC/PEDOT/GO film active functional groups for surface modification. We demonstrate the use of this composite nanofiber for the electrical stimulation of PC12 neural cells as this resultant nanofiber scaffold could closely mimic the structure of the native extracellular matrix (ECM) with a promoting cell orientation and differentiation after electrical stimulation of PC12 cells. It is expected that this biocompatible BC/PEDOT/GO material will find potential applications in biological and regenerative medicine.

Tuning of electrical and optical properties of polyaniline incorporated functional paper for flexible circuits through oxidative chemical polymerization

An organic semiconductor polyaniline based material with outstanding physical properties was prepared on a flexible paper substrate.