Glyoxal crosslinking of electro-responsive alginate-based hydrogels: Effects on the properties.

To improve the features of alginate-based hydrogels in physiological conditions, Ca2+-crosslinked semi-interpenetrated hydrogels formed by poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid and alginate (PEDOT/Alg) were subjected to a treatment with glyoxal to form a dual ionic/covalent network. The covalent network density was systematically varied by considering different glyoxalization times (tG). The content of Ca2+ was significantly higher for the untreated hydrogel than for the glyoxalized ones, while the properties of the hydrogels were found to largely depend on tG. The porosity and swelling capacity decreased with increasing tG, while the stiffness and electrical conductance retention capacity increased with tG. The potentiodynamic response of the hydrogels notably depended on the amount of conformational restraints introduced by the glyoxal, which is a very short crosslinker. Thus, the re-accommodation of the polymer chains during the cyclic potential scans became more difficult with increasing number of covalent crosslinks. This information was used to improve the performance of untreated PEDOT/Alg as electrochemical sensor of hydrogen peroxide by simply applying a tG of 5 min. Overall, the control of the properties of glyoxalized hydrogels through tG is very advantageous and can be used as an on-demand strategy to improve the performance of such materials depending on the application.

Synergy between 3D-extruded electroconductive scaffolds and electrical stimulation to improve bone tissue engineering strategies.

In this work, we propose a simple, reliable, and versatile strategy to create 3D electroconductive scaffolds suitable for bone tissue engineering (TE) applications with electrical stimulation (ES). The proposed scaffolds are made of 3D-extruded poly(ε-caprolactone) (PCL), subjected to alkaline treatment, and of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), anchored to PCL with one of two different crosslinkers: (3-glycidyloxypropyl)trimethoxysilane (GOPS) and divinyl sulfone (DVS). Both cross-linkers allowed the formation of a homogenous and continuous coating of PEDOT:PSS to PCL. We show that these PEDOT:PSS coatings are electroconductive (11.3-20.1 S cm-1), stable (up to 21 days in saline solution), and allow the immobilization of gelatin (Gel) to further improve bioactivity. In vitro mineralization of the corresponding 3D conductive scaffolds was greatly enhanced (GOPS(NaOH)-Gel - 3.1 fold, DVS(NaOH)-Gel - 2.0 fold) and cell colonization and proliferation were the highest for the DVS(NaOH)-Gel scaffold. In silico modelling of ES application in DVS(NaOH)-Gel scaffolds indicates that the electrical field distribution is homogeneous, which reduces the probability of formation of faradaic products. Osteogenic differentiation of human bone marrow derived mesenchymal stem/stromal cells (hBM-MSCs) was performed under ES. Importantly, our results clearly demonstrated a synergistic effect of scaffold electroconductivity and ES on the enhancement of MSC osteogenic differentiation, particularly on cell-secreted calcium deposition and the upregulation of osteogenic gene markers such as COL I, OC and CACNA1C. These scaffolds hold promise for future clinical applications, including manufacturing of personalized bone TE grafts for transplantation with enhanced maturation/functionality or bioelectronic devices.

Novel Electroactive Mineralized Polyacrylonitrile/PEDOT:PSS Electrospun Nanofibers for Bone Repair Applications.

Bone defect repair remains a critical challenge in current orthopedic clinical practice, as the available therapeutic strategies only offer suboptimal outcomes. Therefore, bone tissue engineering (BTE) approaches, involving the development of biomimetic implantable scaffolds combined with osteoprogenitor cells and native-like physical stimuli, are gaining widespread interest. Electrical stimulation (ES)-based therapies have been found to actively promote bone growth and osteogenesis in both in vivo and in vitro settings. Thus, the combination of electroactive scaffolds comprising conductive biomaterials and ES holds significant promise in improving the effectiveness of BTE for clinical applications. The aim of this study was to develop electroconductive polyacrylonitrile/poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PAN/PEDOT:PSS) nanofibers via electrospinning, which are capable of emulating the native tissue's fibrous extracellular matrix (ECM) and providing a platform for the delivery of exogenous ES. The resulting nanofibers were successfully functionalized with apatite-like structures to mimic the inorganic phase of the bone ECM. The conductive electrospun scaffolds presented nanoscale fiber diameters akin to those of collagen fibrils and displayed bone-like conductivity. PEDOT:PSS incorporation was shown to significantly promote scaffold mineralization in vitro. The mineralized electroconductive nanofibers demonstrated improved biological performance as observed by the significantly enhanced proliferation of both human osteoblast-like MG-63 cells and human bone marrow-derived mesenchymal stem/stromal cells (hBM-MSCs). Moreover, mineralized PAN/PEDOT:PSS nanofibers up-regulated bone marker genes expression levels of hBM-MSCs undergoing osteogenic differentiation, highlighting their potential as electroactive biomimetic BTE scaffolds for innovative bone defect repair strategies.

Production of Blended Poly(acrylonitrile): Poly(ethylenedioxythiophene):Poly(styrene sulfonate) Electrospun Fibers for Neural Applications.

This study describes, for the first time, the successful incorporation of poly(ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) in Poly(acrylonitrile) (PAN) fibers. While electroconductive PEDOT:PSS is extremely challenging to electrospun into fibers. Therefore, PAN, a polymer easy to electrospun, was chosen as a carrier due to its biocompatibility and tunable chemical stability when cross-linked, particularly using strong acids. PAN:PEDOT:PSS blends, prepared from PEDOT:PSS Clevios PH1000, were electrospun into fibers (PH1000) with a diameter of 515 ± 120 nm, which after being thermally annealed (PH1000 24H) and treated with heated sulfuric acid (PH1000 H2SO4), resulted in fibers with diameters of 437 ± 109 and 940 ± 210 nm, respectively. The fibers obtained over the stepwise process were characterized through infra-red/Raman spectroscopy and cyclic voltammetry. The final fiber meshes showed enhanced electroconductivity (3.2 × 10-3 S cm-1, four-points-assay). Fiber meshes biocompatibility was evaluated using fibroblasts and neural stem cells (NSCs) following, respectively, the ISO10993 guidelines and standard adhesion/proliferation assay. NSCs cultured on PH1000 H2SO4 fibers presented normal morphology and high proliferation rates (0.37 day-1 vs. 0.16 day-1 for culture plate), indicating high biocompatibility for NSCs. Still, the low initial NSC adhesion of 7% calls for improving seeding methodologies. PAN:PEDOT:PSS fibers, here successful produced for the first time, have potential applications in neural tissue engineering and soft electronics.

Designing Electrical Stimulation Platforms for Neural Cell Cultivation Using Poly(aniline): Camphorsulfonic Acid.

Electrical stimulation is a powerful strategy to improve the differentiation of neural stem cells into neurons. Such an approach can be implemented, in association with biomaterials and nanotechnology, for the development of new therapies for neurological diseases, including direct cell transplantation and the development of platforms for drug screening and disease progression evaluation. Poly(aniline):camphorsulfonic acid (PANI:CSA) is one of the most well-studied electroconductive polymers, capable of directing an externally applied electrical field to neural cells in culture. There are several examples in the literature on the development of PANI:CSA-based scaffolds and platforms for electrical stimulation, but no review has examined the fundamentals and physico-chemical determinants of PANI:CSA for the design of platforms for electrical stimulation. This review evaluates the current literature regarding the application of electrical stimulation to neural cells, specifically reviewing: (1) the fundamentals of bioelectricity and electrical stimulation; (2) the use of PANI:CSA-based systems for electrical stimulation of cell cultures; and (3) the development of scaffolds and setups to support the electrical stimulation of cells. Throughout this work, we critically evaluate the revised literature and provide a steppingstone for the clinical application of the electrical stimulation of cells using electroconductive PANI:CSA platforms/scaffolds.

9-Borafluoren-9-yl and diphenylboron tetracoordinate complexes of F- and Cl-substituted 8-quinolinolato ligands: synthesis, molecular and electronic structures, fluorescence and application in OLED devices.

Six new four-coordinate tetrahedral boron complexes, containing 9-borafluoren-9-yl and diphenylboron cores attached to orthogonal fluorine- and chlorine-substituted 8-quinolinolato ligand chromophores, have been synthesised, characterised, and applied as emitters in organic light-emitting diodes (OLEDs). An extensive steady-state and time-resolved photophysical study, in solution and in the solid state, resulted in the first-time report of delayed fluorescence (DF) in solid films of 8-quinolinolato boron complexes. The DF intensity dependence on excitation dose suggests that this emission originates from triplet-triplet annihilation (TTA). Density functional theory (DFT) and time-dependent density functional theory (TDDFT) studies give insight into the ground and excited state geometries, electronic structures, absorption energies, and singlet-triplet gaps in these new organoboron luminophores. Finally, given their highly luminescent behaviour, organic light-emitting diode (OLED) devices were produced using the synthesised organoboron compounds as emissive fluorescent dopants. The best OLED displays green-blue (λmaxEL = 489 nm) electroluminescence with an external quantum efficiency (EQE) of 3.3% and a maximum luminance of 6300 cd m-2.

Electronic to ionic transduction of the electric field applied to PEDOT:PSS substrates to the cell cultures on top.

The potential of the electrical double layer (EDL) formed at the interface between cross-linked poly (3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) and phosphate-buffered saline (PBS) was measured with respect to a reference Ag/AgCl electrode, yielding a value of ca. 300 mV, which corresponds to a work function of 4.9 eV. More importantly, we report that the application of a voltage along the PEDOT:PSS substrate induces a modification of the EDL, which mirrors the potential applied to the PEDOT:PSS underneath. This is translated into an ionic electric field, tangential to the interface that images the electric field applied to the PEDOT:PSS. We propose that this modification of the EDL, via application of the electrical field away from the cell culture medium, is at origin of the neural stem cell response to that field, when cultured on top of PEDOT:PSS. Despite the comparatively low value of the Debye length (estimated around 1 nm) with respect to the much larger cell to PEDOT:PSS surface distance, we believe that the perturbation of the EDL is the likely source of the increase of neuronal differentiation of the neural stem cells. We discuss other possible implications of that EDL modulation.

Modulation of the electrical double layer in metals and conducting polymers.

The electrical double layer (EDL) formed at the interface between various materials and an electrolyte has been studied for a long time. In particular, the EDL formed at metal/electrolyte interfaces is central in electrochemistry, with a plethora of applications ranging from corrosion to batteries to sensors. The discovery of highly conductive conjugated polymers has opened a new area of electronics, involving solution-based or solution-interfaced devices, and in particular in bioelectronics, namely for use in deep-brain stimulation electrodes and devices to measure and condition cells activity, as these materials offer new opportunities to interface cells and living tissues. Here, it is shown that the potential associated to the double layer formed at the interface between either metals or conducting polymers and electrolytes is modified by the application of an electric field along the conductive substrate. The EDL acts as a transducer of the electric field applied to the conductive substrate. This observation has profound implications in the modelling and operation of devices relying on interfaces between conductive materials (metals and conjugated polymers) and electrolytes, which encompasses various application fields ranging from medicine to electronics.

PEDOT:PSS-Coated Polybenzimidazole Electroconductive Nanofibers for Biomedical Applications.

Bioelectricity drives several processes in the human body. The development of new materials that can deliver electrical stimuli is gaining increasing attention in the field of tissue engineering. In this work, novel, highly electrically conductive nanofibers made of poly [2,2'-m-(phenylene)-5,5'-bibenzimidazole] (PBI) have been manufactured by electrospinning and then coated with cross-linked poly (3,4-ethylenedioxythiophene) doped with poly (styrene sulfonic acid) (PEDOT:PSS) by spin coating or dip coating. These scaffolds have been characterized by scanning electron microscopy (SEM) imaging and attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy. The electrical conductivity was measured by the four-probe method at values of 28.3 S·m-1 for spin coated fibers and 147 S·m-1 for dip coated samples, which correspond, respectively, to an increase of about 105 and 106 times in relation to the electrical conductivity of PBI fibers. Human bone marrow-derived mesenchymal stromal cells (hBM-MSCs) cultured on the produced scaffolds for one week showed high viability, typical morphology and proliferative capacity, as demonstrated by calcein fluorescence staining, 4',6-diamidino-2-phenylindole (DAPI)/Phalloidin staining and MTT [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide] assay. Therefore, all fiber samples demonstrated biocompatibility. Overall, our findings highlight the great potential of PEDOT:PSS-coated PBI electrospun scaffolds for a wide variety of biomedical applications, including their use as reliable in vitro models to study pathologies and the development of strategies for the regeneration of electroactive tissues or in the design of new electrodes for in vivo electrical stimulation protocols.

Electrical stimulation of neural-differentiating iPSCs on novel coaxial electroconductive nanofibers.

Neural tissue engineering strategies are paramount to create fully mature neurons, necessary for new therapeutic strategies for neurological diseases or the creation of reliable in vitro models. Scaffolds can provide physical support for these neurons and enable cues for enhancing neural cell differentiation, such as electrical current. Coaxial electrospinning fibers, designed to fulfill neural cell needs, bring together an electroconductive shell layer (PCL-PANI), able to mediate electrical stimulation of cells cultivated on fibers mesh surface, and a soft core layer (PGS), used to finetune fiber diameter (951 ± 465 nm) and mechanical properties (1.3 ± 0.2 MPa). Those dual functional coaxial fibers are electroconductive (0.063 ± 0.029 S cm-1, stable over 21 days) and biodegradable (72% weigh loss in 12 hours upon human lipase accelerated assay). For the first time, the long-term effects of electrical stimulation on induced neural progenitor cells were studied using such fibers. The results show increase in neural maturation (upregulation of MAP2, NEF-H and SYP), up-regulation of glutamatergic marker genes (VGLUT1 - 15-fold) and voltage-sensitive channels (SCN1α - 12-fold, CACNA1C - 32-fold), and a down-regulation of GABAergic marker (GAD67 - 0.09-fold), as detected by qRT-PCR. Therefore, this study suggest a shift from an inhibitory to an excitatory neural cell profile. This work shows that the PGS/PCL-PANI coaxial fibers here developed have potential applications in neural tissue engineering.

Effect of Electrical Stimulation Conditions on Neural Stem Cells Differentiation on Cross-Linked PEDOT:PSS Films.

The ability to culture and differentiate neural stem cells (NSCs) to generate functional neural populations is attracting increasing attention due to its potential to enable cell-therapies to treat neurodegenerative diseases. Recent studies have shown that electrical stimulation improves neuronal differentiation of stem cells populations, highlighting the importance of the development of electroconductive biocompatible materials for NSC culture and differentiation for tissue engineering and regenerative medicine. Here, we report the use of the conjugated polymer poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS CLEVIOS P AI 4083) for the manufacture of conductive substrates. Two different protocols, using different cross-linkers (3-glycidyloxypropyl)trimethoxysilane (GOPS) and divinyl sulfone (DVS) were tested to enhance their stability in aqueous environments. Both cross-linking treatments influence PEDOT:PSS properties, namely conductivity and contact angle. However, only GOPS-cross-linked films demonstrated to maintain conductivity and thickness during their incubation in water for 15 days. GOPS-cross-linked films were used to culture ReNcell-VM under different electrical stimulation conditions (AC, DC, and pulsed DC electrical fields). The polymeric substrate exhibits adequate physicochemical properties to promote cell adhesion and growth, as assessed by Alamar Blue® assay, both with and without the application of electric fields. NSCs differentiation was studied by immunofluorescence and quantitative real-time polymerase chain reaction. This study demonstrates that the pulsed DC stimulation (1 V/cm for 12 days), is the most efficient at enhancing the differentiation of NSCs into neurons.

Polyaniline-polycaprolactone fibers for neural applications: Electroconductivity enhanced by pseudo-doping.

Replenishing neurons in patients with neurodegenerative diseases is one of the ultimate therapies for these progressive, debilitating and fatal diseases. Electrical stimulation can improve neuron stem cell differentiation but requires a reliable nanopatterned electroconductive substrate. Potential candidate substrates are polycaprolactone (PCL) - polyaniline:camphorsulfonic acid (PANI:CSA) nanofibers, but their nanobiophysical properties need to be finetuned. The present study investigates the use of the pseudo-doping effect on the optimization of the electroconductivity of these polyaniline-based electrospun nanofibers. This was performed by developing a new solvent system that comprises a mixture of hexafluoropropanol (HFP) and trifluoroethanol (TFE). For the first time, an electroconductivity so high as 0.2 S cm-1 was obtained for, obtained from a TFE:HFP 50/50 vol% solution, while maintaining fiber biocompatibility. The physicochemical mechanisms behind these changes were studied. The results suggest HFP promotes changes on PANI chains conformations through pseudo-doping, leading to the observed enhancement in electroconductivity. The consequences of such change in the nanofabrication of PCL-PANI fibers include an increase in fiber diameter (373 ± 172 nm), a decrease in contact angle (42 ± 3°) and a decrease in Young modulus (1.6 ± 0.5 MPa), making these fibers interesting candidates for neural tissue engineering. Electrical stimulation of differentiating neural stem cells was performed using AC electrical current. Positive effects on cell alignment and gene expression (DCX, MAP2) are observed. The novel optimized platform shows promising applications for (1) building in vitro platforms for drug screening, (2) interfaces for deep-brain electrodes; and (3) fully grown and functional neurons transplantation.

The effect of electrospun scaffolds on the glycosaminoglycan profile of differentiating neural stem cells.

The use of electrospun scaffolds for neural tissue engineering applications allows a closer mimicry of the native tissue extracellular matrix (ECM), important for the transplantation of cells in vivo. Moreover, the role of the electrospun fiber mat topography on neural stem cell (NSC) differentiation remains to be completely understood. In this work REN-VM cells (NSC model) were differentiated on polycaprolactone (PCL) nanofibers, obtained by wet/wet electrospinning, and on flat glass lamellas. The obtained differentiation profile of NSCs was evaluated using immunofluorescence and qPCR analysis. Glycosaminoglycan (GAG) analysis was successfully emplyed to evaluate changes in the GAG profile of differentiating cells through the use of the highly sensitive liquid chromatography-tandem mass/mass spectrometry (LC-MS/MS) method. Our results show that both culture platforms allow the differentiation of REN-VM cells into neural cells (neurons and astrocytes) similarly. Moreover, LC-MS/MS analysis shows changes in the production of GAGs present both in cell cultures and conditioned media samples. In the media, hyaluronic acid (HA) was detected and correlated with cellular activity and the production of a more plastic extracellular matrix. The cell samples evidence changes in chondroitin sulfate (CS4S, CS6S, CS4S6S) and heparan sulfate (HS6S, HS0S), similar to those previously described in vivo studies and possibly associated with the creation of complex structures, such as perineural networks. The GAG profile of differentiating REN-VM cells on electrospun scaffolds was analyzed for the first time. Our results highlight the advantage of using platforms obtain more reliable and robust neural tissue-engineered transplants.

Ambipolar pentacyclic diamides with interesting electrochemical and optoelectronic properties.

Developing organic semiconductors for organic thin film transistors (OTFT) and optoelectronic applications is a challenge. We developed highly crystalline pentacyclic diimides (3) and (4) which showed good OTFT and OLED potential and energy gaps of 2.60 eV and 2.54 eV. They exhibited interesting photo and eletroluminescence activity. Both compounds showed good quantum yields (0.56 for (3) and 0.60 for (4)).

Luminescent halogen-substituted 2-(N-arylimino)pyrrolyl boron complexes: the internal heavy-atom effect.

A group of new boron complexes [BPh2{κ2N,N'-NC4H3-2-C(H)[double bond, length as m-dash]N-C6H4X}] (X = 4-Cl 4c, 4-Br 4d, 4-I 4e, 3-Br 4f, 2-Br 4g, 2-I 4h) containing different halogens as substituents in the N-aryl ring have been synthesized and characterized in terms of their molecular properties. Their photophysical characteristics have been thoroughly studied in order to understand whether these complexes exhibit an internal heavy-atom effect. Phosphorescence emission was found for some of the synthesized halogen-substituted boron molecules, particularly for 4g and 4h. DFT and TDDFT calculations showed that the lower energy absorption band resulted from the HOMO to LUMO (π-π*) transition, except for 2-I 4h, where the HOMO-1 to LUMO transition was also involved. The strong participation of iodine orbitals in HOMO-1 is reflected in the calculated absorption spectra of the iodine derivatives, especially 2-I 4h, when spin-orbit coupling (SOC) was included. Organic light-emitting diodes (OLEDs) based on these complexes, in the neat form or dispersed in a matrix, were also fabricated and tested. The devices based on films prepared by thermal vacuum deposition showed the best performance. When neat complexes were used, a maximum luminance (Lmax) of 1812 cd m-2 was obtained, with a maximum external quantum efficiency (EQEmax) of 0.15%. An EQEmax of ca. 1% along with a maximum luminance of 494 cd m-2 were obtained for a device fabricated by co-deposition of the boron complex and a host compound (1,3-bis(N-carbazolyl)benzene, mCP).

Boron complexes of aromatic 5-substituted iminopyrrolyl ligands: synthesis, structure, and luminescence properties.

A group of new mononuclear boron chelate compounds [BPh2{κ2N,N'-5-R-NC4H2-2-C(H)[double bond, length as m-dash]N-Ar}] (R = Ar = C6H57; R = C6H5, Ar = 2,6-iPr2C6H38; R = Anthracen-9-yl (Anthr), Ar = C6H59; R = Anthr, Ar = 2,6-iPr2C6H310) were synthesized via the reaction of B(C6H5)3 with the corresponding 5-substituted 2-(N-arylformimino)pyrrole ligand precursors 3-6. These complexes were prepared in order to evaluate the luminescence potential derived from the substitution of the position 5 of the pyrrolyl ring with an aromatic group. Compounds 7-10 were photophysically characterized in solution and in the solid state. The 5-phenyl-2-iminopyrrolyl-BPh2 complexes 7 and 8 are blue emitters and have enhanced photoluminescence quantum yields in the solid state (ΦPL) up to 0.95, whereas the 5-anthracenyl derivatives 9 and 10 have green-bluish fluorescence and a ΦPL of 0.49 and 0.24, respectively. DFT and TDDFT studies were performed, considering the effect of solvent and dispersion, in order to show how the geometries of compounds 7-10 changed from the ground to the excited state, to assign electronic transitions, and to rationalize the observed luminescence. These materials were applied in organic light-emitting diodes (OLEDs), with various device structures, the best showing an external quantum efficiency of 2.75% together with a high luminance of 23 530 cd m-2.

Bottom-Up Self-Assembled Supramolecular Structures Built by STM at the Solid/Liquid Interface.

One of the lines of research on organic devices is focused on their miniaturization to obtain denser and faster electronic circuits. The challenge is to build devices adding atom by atom or molecule by molecule until the desired structures are achieved. To do this job, techniques able to see and manipulate matter at this scale are needed. Scanning tunneling microscopy (STM) has been the selected technique by scientists to develop smart and functional unimolecular devices. This review article compiles the latest developments in this field giving examples of supramolecular systems monitored and fabricated at the molecular scale by bottom-up approaches using STM at the solid/liquid interface.

Self-Assembled Multilayer Films for Time-Controlled Ocular Drug Delivery.

The patient's compliance on the therapeutics to treat glaucoma is significantly low contributing for a fast evolution of the disease. This article presents an autonomous system with controlled release using an alpha2-adrenergic receptor agonist, brimonidine, usually used to treat glaucoma. More specifically, biocompatible and layer-by-layer drug delivery films containing monolayers with brimonidine encapsulated in polymer-ß-cyclodextrin were prepared with the objective to obtain a system able to release precise amounts of drug at specific times. To delay the erosion-controlled drug release, we included nanosheets of graphene oxide and layers of a biodegradable polymer (poly-ß-aminoester) between the drug-containing monolayers to obtain a time-controlled drug delivery system. An increase in the number of graphene oxide layers is proportional to the brimonidine release delay and its kinetic release can be tuned as a function of the number of layers. Two types of films with brimonidine encapsulated in ß-cyclodextrin were analyzed. One of them composed of barrier layers with PBAE and another with two types of barrier layers, PBAE and graphene oxide. The results indicate that one graphene oxide bilayer can delay the brimonidine release for more than 24 h. In vitro assays confirmed that the films have a cell viability of 100%.

POLYBENZIMIDAZOLE NANOFIBERS FOR NEURAL STEM CELL CULTURE.

Neurodegenerative diseases compromise the quality of life of increasing numbers of the world's aging population. While diagnosis is possible no effective treatments are available. Strong efforts are needed to develop new therapeutic approaches, namely in the areas of tissue engineering and deep brain stimulation (DBS). Conductive polymers are the ideal material for these applications due to the positive effect of conducting electricity on neural cell's differentiation profile. This novel study assessed the biocompatibility of polybenzimidazole (PBI), as electrospun fibers and after being doped with different acids. Firstly, doped films of PBI were used to characterize the materials' contact angle and electroconductivity. After this, fibers were electrospun and characterized by SEM, FTIR and TGA. Neural Stem Cell's (NSC) proliferation was assessed and their growth rate and morphology on different samples was determined. Differentiation of NSCs on PBI - CSA fibers was also investigated and gene expression (SOX2, NES, GFAP, Tuj1) was assessed through Immunochemistry and qPCR. All the samples tested were able to support neural stem cell (NSC) proliferation without significant changes on the cell's typical morphology. Successfully differentiation of NSCs towards neural cells on PBI - CSA fibers was also achieved. This promising PBI fibrous scaffold material is envisioned to be used in neural cell engineering applications, including scaffolds, in vitro models for drug screening and electrodes.