Surface functionalization of PEEK with silicon nitride

Abstract

Surface roughness, bioactivity, and antibacterial properties are desirable in skeletal implants. We hot-pressed a mix of particulate sodium chloride (NaCl) salt and silicon nitride (β-Si3N4) onto the surface of bulk PEEK. NaCl grains were removed by leaching in water, resulting in a porous PEEK surface embedded with sim15 vol% β-Si3N4 particles. This functionalized surface showed the osteogenic and antibacterial properties previously reported in bulk silicon nitride implants. Surface enhancement of PEEK with β-Si3N4 could improve the performance of spinal fusion cages, by facilitating arthrodesis and resisting bacteria.

Assessment of skin inflammation using near-infrared Raman spectroscopy combined with artificial intelligence analysis in an animal model

“…These spectra have also been reported in previous papers and are thought to be due to the lipid components of the skin. 18 In the inflamed skin, we frequently observed a single sharp peak at 1550 cm −1 followed by a bimodal peak in the wavenumber region from 1600 cm −1 to 1630 cm −1 , which occurred between the peaks of the carbon double bond of the aromatic ring at 1450 cm −1 and the linear carbon double bond at 1660 cm −1 (Fig. 2A).…”

“…Among the extracted PCs, PC2 appeared to contain spectra of carbon double bonds and CH bonds, which may have been derived from phospholipids. 18 The ROC curve created based on PC2 showed relatively high accuracy in predicting skin inflammation (Fig. 5, the second panels from the left), although the rate was insufficient for clinical diagnosis.…”

“…Inflammation decreased the peaks observed at 1450 cm −1 and 1660 cm −1 for carbon double bonds, which are frequently observed in Raman spectroscopy of living cells or organs and are considered to represent fats or membrane phospholipids. 18 Attenuation of these two peaks may indicate a decrease in the lipid barrier of the skin or changes in cellular composition due to interstitial oedema. We also observed broad-spectrum morphological changes at 2800–3000 cm −1 , which were assigned to the stretch of CH bonds.…”

Modification strategies for improving antibacterial properties of polyetheretherketone

“…It was found that the modified material has the functions of antibacterial and promoting osteogenesis. [68][69][70] 2.8 | Graphene oxide coating GO, a critical graphene derivative, is a single atom nanosheet with a dense honeycomb structure and possesses a large number of ROS functional groups. GO can induce oxidative stress reaction and produce antibacterial activity mainly by acting on bacterial cell membrane through ROS and sharp edges.…”

“…Some scholars introduced silicon nitride into the surface or interior of PEEK through melt blending, hot pressing, and chemical vapor deposition. It was found that the modified material has the functions of antibacterial and promoting osteogenesis 68–70 …”