1. Carbono 2015 - 6° Congresso Brasileiro de Carbono
Scaffolds grafíticos condutivos baseados em fibras de carbono para aplicações biomédicas
Eduardo Jose de Arruda1*, Jossano Saldanha Marcuzzo2,3*, João Oliveira Ventura4, Jose Tiago Teixeira Cardoso4, Catarina Dias4, Marisa Masumi Beppu5 e Fernando Jorge Mendes Monteiro6,7
1*Universidade Federal da Grande Dourados - UFGD, Dourados-MS, Brasil
2*Faculdade de Tecnologia de São Paulo - FATEC, São José dos Campos, SP, Brasil
3*Instituto Nacional de Pesquisas Espaciais - INPE, São José dos Campos, Brasil
4 FIMUP – IN / Faculdade de Ciências da Universidade do Porto, Porto, Portugal
5 Faculdade de Engenharia Química da Unicamp – FEQ-UNICAMP, Campinas-SP, Brasil
6 Faculdade de Engenharia da Universidade do Porto - FEUP, Porto, Portugal
7Instituto de Engenharia Biomédica-INEB/i3S, Porto, Portugal
Abstract: Carbon fibers not activated (NACF) or activated (ACF) were obtained by heat treatment of the polyacrylonitrile (PAN). These scaffolds allow the deposition of natural polymers and proposed are for technological and/or biomedical applications. The structures are self-supporting, they have different porosities, adsorption, conductivity and chemical composition. Conductivity measurements showed that the material allows the movement of electrons temperature dependent and/or that be transported due to size and concentration of graphitic domains. The deposition of polymers or polymer blends may allow biological activity, adhesion/attachment, growth and proliferation of cardiac, neuronal and osteogenic cells due to conduction and/or electrical stimulation. The resistivity were performed using the Van der Pauw 4 contacts method. The values ​​of resistivity for NACF, ACF and carbon content (C) confirmed the conductivity of the samples and their potential to be used as graphitic structures to impregnate with biomaterials for regenerative and/or induction cell growth processes.
Keywords: cell frameworks, turbostratic microcrystallites, conductivity, cellular communication
The arrangements and frameworks of the carbon fibers are shown in Figure 1.
Figure 1. SEM micrographs A) NACF 250x, B) ACF 250x.
Conclusions
The results show the influence of the carbon fiber´s treatment in the conductivity and the relation with the elemental content. The fiber arrays are conductive graphitic structures for impregnation of natural polymers. These arrays have potential as matrix support for adhesion, proliferation and cell growth. The regeneration process of cell differentiation may be accomplished by cellular communication cell with or without electrostimulation.
Acknowledgements: CAPES/FCT, CNPq, FAPESP, FEQ/UNICAMP, UFGD, FEUP, INEB/i3S, FCUP e FATECSP.
References:
[1] J.S Marcuzzo; C. Otani.; H.A Polidoro; S. Otani. Influence of thermal treatment on porosity formation on carbon fiber from textile PAN. Mat. Research. 16, , 2012.
[2] A.L Efros, BI Shklovskii. Coulomb gap and low temperature conductivity of disordered systems. J. Phys. C: Solid State Phys. 8,4 L49, doi: / /8/4/003
[3] L.J Van der Pauw. A method of measuring the resistivity and Hall coefficient on lamellae of arbitrary shape (PDF). Philips Technical Review 20, 220–224, Available from:
Introduction/Background
Non-activated Carbon Fibers (NACF) and Activated (ACF) can be used as conductive supports for scaffolds with natural polymers (collagen, chitosan, others and their blends) for biomedical applications. Carbon fibers have interesting multifunctional characteristics, as: (i) self-supporting structures, (ii) electrical conductivity associated with surface composition, (iii) filament shape and (iv) high porosity.
Materials and Methods
NACF and ACF were prepared by the Marcuzzo method [1] using thermal processes in controlled atmosphere from PAN (polyacrylonitrile). Briefly, the PAN fiber was turned into fiber felts by oxidation, carbonization and activation processes. We used 3D arranged carbon fibers that changed this material into a conductivity scaffold [2]. Fibers size and graphitic domains enable multiple applications. The electrical characteristics and elemental composition of carbon fiber felts were determined before the impregnation of collagen I, chitosan and blends of 2.5% acetic solutions in the proportions from 1:4, to 3:1 (w/w) to analyze the biological activity, adhesion, growth and proliferation of cardiac, neuronal and osteogenic cells by electrical conduction and/or electrical stimulation.
Results
The resistivity (conductivity) was measured using the Van der Pauw method [3] with fixed electrodes at the samples perimeter. Electrical measurements were performed for samples before impregnation coating process on the NACF and ACF fibers. The elemental composition of NACF and ACF was determined using X-ray Photoelectron Spectroscopy (XPS). The conductivities were: NACF 1,91E-03 Ω.m (5.23 S cm-1) and ACF 2,06E-03 Ω.m (4.86 S cm-1). The elemental compositions found by XPS were: NACF (C) 95.87%, (O) 2.80%, (N) 1.20%); ACF (C) 97.54%, (O) 1.90% and (N) 0.56%). A B