Surface Bioactivation of Polyether Ether Ketone (PEEK) by Sulfuric Acid and Piranha Solution: Influence of the Modification Route in Capacity for Inducing Cell Growth

Abstract

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) for Biomedical Applications: From Enhancing Bioactivity to Reinforced-Bioactive Composites—An Overview

“…Chemical modifications introduce chemical groups into PEEK’s surface, creating a series of surface-functionalized PEEKs. It changes the surface chemical structure of PEEK to generate an environment with a favorable cellular response [ 15 , 69 ]. Zheng et al [ 70 ] prepared a series of modified PEEK with the functional groups -COOH, -OH, and -PO 4 H 2 .…”

“…Another way to introduce sulfonate groups into PEEK’s surface is the treatment with the so-called “piranha” solution. Dos Santos et al [ 69 ] compared the sulfonation process with sulfuric acid and piranha solutions and proved that both methods were efficient in supporting fibroblast adhesion and proliferation. A further chemical modification is the amination of PEEK.…”

Strategies to improve bioactive and antibacterial properties of polyetheretherketone (PEEK) for use as orthopedic implants

“…Santos et al. treated PEEK with sulfuric acid and hydrogen peroxide solution for 60 ​s, and the experimental results showed that the modified surface promoted the adhesion and proliferation of human fibroblasts cells [ 99 ].…”

“… [ 92 ] Concentrated sulfuric acid, ASP, BFP In vitro : increased cytocompatibility and differentiation; improved anti-inflammatory activity. [ 93 ] Concentrated sulfuric acid, hydrogen peroxide In vitro : promoted the adhesion and proliferation of human fibroblasts cells [ 99 ] Nano-structured PEEK surfaces PAA, PAH In vitro : increased cytocompatibility and differentiation; improved anti-inflammatory activity; In vivo : reduced fibrous sac formation and improved bone regeneration of rat femur. [ 130 ] Nanoporous lithium, NLS In vitro : increased cytocompatibility and differentiation; enhanced water absorption and protein absorption, apatite formation in SBF; In vivo : Enhanced bone formation of rabbit femur in comparison to PKLs and PK.…”

"Sneak Peek on Polyetheretherketone (Peek) in Dentistry- A Narrative Review"

“…and hydrogen peroxide (H2O2)) results in increased functional groups on the surface for bonding [41]. Rea et al, evaluated soft and hard tissue healing using different forms of PEEK healing screws [42].…”