Abstract
Porous silica is an attractive biomaterial in many applications, including drug-delivery systems, bone-graft fillers and medical devices. The issue with porous silica biomaterials is the rate at which they resorb and the significant role played by interfacial chemistry on the host response in vivo. This paper explores the potential of diatom-biosilica as a model tool to assist in the task of mapping and quantifying the role of surface topography and chemical cues on cell fate. Diatoms are unicellular microalgae whose cell walls are composed of, amorphous nanopatterned biosilica that cannot be replicated synthetically. Their unique nanotopography has the potential to improve understanding of interface reactions between materials and cells. This study used Cyclotella meneghiniana as a test subject to assess cytotoxicity and pro-inflammatory reactions to diatom-biosilica. The results suggest that diatom-biosilica is non-cytotoxic to J774.2 macrophage cells, and supports cell proliferation and growth. The addition of amine and thiol linkers have shown a significant effect on cytotoxicity, growth and cytokine response, thus warranting further investigation into the interfacial effects of small chemical modifications to substrate surfaces. The overall findings suggest diatom-biosilica offers a unique platform for in-depth investigation of the role played by nanotopography and chemistry in biomedical applications.
Highlights
® 45S51,2 and Si-substituted pastes[3]
As expected, were the most abundant ions, 383,178(±932) mg/kg, detected in the frustules, followed by Ca ions, which were detected at a concentration of 19,929(±297) mg/kg
S 2p was not detected in the other two groups (Fig. 2f). These results suggest that the silanisation reaction has been successful for the respective linkers and this was confirmed by Carbon Hydrogen Nitrogen Sulphur (CHNS) analysis data (Table 2), which showed similar trends
Summary
® 45S51,2 and Si-substituted pastes[3]. Bioglass 45S5 (trade name PerioGlas ) developed by Larry Hench[1] is one ® ® of the most successful silica-based products used clinically[4]. The release profile has not been sufficiently quantified to ascertain its therapeutic concentration, if the biological response is a direct result of Si ion dissolution. Diatoms are unicellular algae that synthesise species-specific amorphous silica cell walls known as frustules[15,16] that are identically replicated from generation to generation[17,18]. There are currently estimated to be over 200,000 different diatom species, each with their own unique shape and morphology[15,18,22] This offers a huge array of surface topographies, particle sizes and shapes, which could be used to help understand the role of silica in bone repair and the influence of material attributes on the cell response. Frustules were functionalised with amino and thiol end groups following isolation from their organic matrix
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