Table 1: In vitro chemical methods for nanosurface modification.

In Vitro Studies
Method Controlled Variables Nanoscale surface features Outcomes References
Anodization Nanotube length, oxide layer thickness, nano crystallinity, pore size Nanotubes with a diameter < 100nm Enhanced adhesion, proliferation, matrix secretion and mineralisation in bone models. Promotion of human MSC growth and differentiation, increased assembly of focal adhesions. Increased chondrocyte adhesion and keratinocyte proliferation [50, 52-55, 60, 63, 68, 91, 94-96, 104, 118-124]
Oxidative nanopatterning Oxide deposition thickness, chemical moeities, Micro & nanotopograpy Nanoporous diameters of 20-100nm Increased osteoblast activity and limits to fibroblast growth. Increased Bone sialoprotein, osteoopontin, alkaline phosphatase, RunX2 expretion. Stimulation of Human umbilical cord stem cells [29, 34, 65, 97, 99, 100]
Chemical Vapor Deposition & Sol-Gel processes Nanosurface roughness. Nanolayer thickness and nano-crystallinity Nanotopography Increased osteoblast adhesion and proliferation [64, 91, 110, 112, 125-132]
Biochemical functionalisation Thickness of biochemical coatings. Control of the functional groups RGD protein motifs, extrcellular proteins and amino acid segments. Nanorosette, antibiotics, non fouling and anticoagulant sequence Increased osteoblast activity including adhesion, gene expresion and proliferation [41-43, 50, 73, 133-136]
Acid/Alkali Treatment Acid solution concentration, relative thickness of the oxide layer.Porosity, layer thickness, two layer structure
Crystallinity
Nanosurface reactive groups. Acid etching leadings to thin surface oxide layers, that grow slowly in air. Two step chemical reactions can be epmployed to improve bioactivity. Alkali and heat treatment improved pore size and corrosion resistance. Apatite formation increased with alkali treatment [29, 137, 138]
[43, 105, 112, 139, 140]