The aim of this study was to promote bioactivity of the PEEK surface using sulfuric acid and piranha solution. PEEK was functionalized by a sulfuric acid treatment for 90 s and by piranha solution for 60 and 90 s. Chemical modification of the PEEK surface was evaluated by infrared spectroscopy, contact angle analysis, cytotoxicity, cell adhesion and proliferation. The spectroscopy characteristic band associated with sulfonation was observed in all treated samples. PEEK with piranha solution 60 s showed an increase in the intensity of the bands, which was even more significant for the longer treatment (90 s). The introduction of the sulfonic acid functional group reduced the contact angle. In cytotoxicity assays, for all treatments, the number of viable cells was higher when compared to those of untreated PEEK. PEEK treated with sulfuric acid and piranha solution for 60 s were the treatments that showed the highest percentage of cell viability with no statistically significant differences between them. The modified surfaces had a greater capacity for inducing cell growth, indicative of effective cell adhesion and proliferation. The proposed chemical modifications are promising for the functionalization of PEEK-based implants, as they were effective in promoting bioactivation of the PEEK surface and in stimulating cell growth and proliferation.

Poly(ether ether ketone) (PEEK) has excellent properties, such as high biocompatibility and an elastic modulus similar to bone, which makes it a suitable biomaterial. When modified with sulfuric acid (H 2 SO 4) and hydroxyapatite (HA), its workability and bioactivity is enhanced, and this makes it of great importance in medicine. This study investigates a better combination of process parameters to manufacture sulfonated PEEK/HA (SPEEK/HA) membranes for biomaterials. Chemical, thermal, and biological analyses were carried out on all samples. The sulfonated structure was observed to enhance wettability, adhesion, and cell viability. Furthermore, an increase in the degree of sulfonation facilitated their workability as required for biomaterials; making them suitable for osseointegration. Besides, the SPEEK/HA membranes presented cell adhesion, confirming the viability to use as biomaterial. This study presents a cheap alternative method to easily process biomaterials of improved workability.

This study aimed to achieve bioactivity on the PEEK surface using piranha solution through a lower functionalization time. For this purpose, the functionalization occurred with piranha solution and 98% sulfuric acid in the proportions of 1:2, 1:1, and 2:1 at periods of 30, 60, and 90 s. The samples treated for longer times at higher concentrations registered the characteristic spectroscopy band associated with sulfonation. Additionally, both chemical treatments allowed the opening of the aromatic ring, increasing the number of functional groups available and making the surface more hydrophilic. The piranha solution treatments with higher concentrations and longer times promoted greater heterogeneity in the surface pores, which affected the roughness of untreated PEEK. Furthermore, the treatments induced calcium deposition on the surface during immersion in SBF fluid. In conclusion, the proposed chemical modifications using sulfuric acid SPEEK 90 and, especially, the piranha solution PEEK-PS 2:1-90, were demonstrated to be promising in promoting the rapid bioactivation of PEEK-based implants.

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RESUMO O poli (éter-éter-cetona) - (PEEK) é conhecido como um biomaterial alternativo para a substituição de materiais metálicos implantáveis. No entanto, para aplicações biomédicas ele é biologicamente inerte, impedindo uma boa interação entre o implante e os tecidos ósseos adjacentes, dificultando a sua aplicação. Uma maneira de superar o caráter inerte do PEEK é a modificação física da sua superfície pelo método de lixiviação de partículas. Dessa forma, este trabalho teve como objetivo desenvolver e caracterizar estruturas de PEEK com superfície modificada. Para a preparação das estruturas utilizou-se a técnica de deposição de uma camada de NaCl sobre o polímero. Esse material foi submetido a uma carga de 6 toneladas seguido de tratamento térmico a 390°C durante três diferentes tempos. Após o resfriamento, as amostras foram submetidas ao processo de lixiviação de partículas de NaCl. Em seguida, as estruturas foram caracterizadas por Microscopia Ótica, retilineidade e FTIR. O aumento de tempo no tratamento térmico conduziu as amostras a uma melhor conformação e preservação das cavidades presentes na superfície rugosa como consequência de uma melhor fusão do polímero, porém provocou uma menor efetividade na lixiviação das partículas de NaCl. No ensaio de retilineidade, a amostra que apresentou menor rugosidade foi a com maior tempo de tratamento térmico, possivelmente devido a uma maior quantidade de NaCl retido em sua superfície rugosa. A partir das observações dos espectros, as amostras de PEEK, quando comparadas à amostra controle, apresentaram um comportamento similar, não demonstrando alteração significativa no perfil entre os materiais estudados. Considerando os aspectos de processamento, a técnica desenvolvida nesta pesquisa demonstrou-se efetiva para a obtenção das amostras de PEEK com superfície modificada com diferentes tempos de tratamento térmico.