High loading of graphene oxide/multi-walled carbon nanotubes into PDLLA: A route towards the design of osteoconductive, bactericidal and non-immunogenic 3D porous scaffolds

• We produced a novel 3D porous material from PDLLA, graphene oxide and MWCNT oxide.
• MWCNTO-GO loading (50/50 w/w) increased notably the conductivity of PDLLA scaffold.
• MWCNTO-GO acted protecting the PDLLA matrix, enhancing its thermal stability.
• PDLLA/MWCNTO-GO scaffolds did not present cytotoxicity effect.
• PDLLA/MWCNTO-GO scaffolds presented bioactivity properties.

We have prepared a novel 3D porous biomaterial combining poly (dl-lactic acid) (PDLLA) and graphene and multi-walled carbon nanotubes oxides (MWCNTO-GO) composite. PDLLA as control and a high loading of PDLLA/MWCNTO-GO (50/50 w/w) bioscaffolds were prepared and functionalized. MWCNTs were exfoliated to form MWCNTO-GO by oxygen plasma etching. The later was also applied to enhance the scaffolds wettability, attaching oxygen-containing groups on their surfaces. This approach produced a porous architecture observed by scanning electron microscopy and semi-quantified by electrochemical analysis. The later also indicated a notable increase on the conductivity of PDLLA/MWCNTO-GO scaffold compared to MWCNTO-GO free PDLLA (about 5 orders of magnitudes at low frequencies). Thermogravimetric analysis showed that the MWCNTO-GO acted protecting the PDLLA matrix, enhancing its thermal stability. The PDLLA/MWCNTO-GO scaffolds had significant cellular adhesion, did not present cytotoxicity effect, besides reduced bactericidal proliferation and produced mineralized tissues in SBF media. The metallic MWCNTO-GO powder held together by PDLLA polymer opens a whole new branch of applications, including bioelectroanalyses, drug delivery systems and tissue engineering.

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