Optimizing the osteogenicity of nanotopography using block co‐polymer phase separation fabrication techniques

Abstract

Both temporary and permanent orthopedic implants have, by default or design, surface chemistry, and topography. There is increasing evidence that controlling nanodisorder can result in increased osteogenesis. Block co-polymer phase separation can be used to fabricate a nanotopography exhibiting a controlled level of disorder, both reproducibly and cost-effectively. Two different topographies, produced through the use of block co-polymer phase separation, were embossed onto the biodegradable thermoplastic, polycaprolactone (PCL). Analysis of the topography itself was undertaken with atomic force microscopy, and the topography's effect on human osteoblasts studied through the use of immunocytochemistry and fluorescence microscopy. Planar controls had a surface roughness 0.93 nm, and the substrates a high fidelity transfer of a disordered pattern of 14 and 18 nm. Cytoskeletal organization and adhesion, and increased expression of Runx2 were significantly greater on the smallest nanotopography. Expression of osteopontin and osteocalcin protein, and alizarin red staining of bone nodules were greatest on the smallest feature nanopatterns. Highly osteogenic, disordered nanotopographies can be manufactured into thermoplastics in a rapid and cost-effective way through the use of block co-polymer phase separation. Osteogenic topographies reproducibly and cost-effectively produced have a potentially useful application to the fields of implant technology and regenerative orthopedics. ß

2D and 3D Nanopatterning of Titanium for Enhancing Osteoinduction of Stem Cells at Implant Surfaces

“…The arrangement, or order, of nanotopographies is known to be highly important for controlling cell behaviour 1. BCP films4 and surfaces embossed from BCP patterned templates28 have previously been used to control cell response and here we have clearly shown that it is possible to translate such topographies onto Ti surfaces.…”

Nanotopographical surfaces for stem cell fate control: Engineering mechanobiology from the bottom

“…In recent years, block copolymer lithography has been directly applied to generate nanotopographical surfaces for cell assays. Maclaine et al ., for example, have used poly(styrene-block-poly-2-vinylpyridine) (PS- b -P2VP) block copolymer micelles to generate nanoscale islands of 20 nm in height and 150 nm in in-plane periodicity [125]. Using a novel PS-PDMS diblock copolymer, Salaun et al have achieved fabrication of PDMS nanopillars of 10 nm in height and 20 nm in width [126].…”

Analysis of Osteoclastogenesis/Osteoblastogenesis on Nanotopographical Titania Surfaces

“…Block copolymer self‐assembly provides a technique that can produce arrays of slightly disordered, but not random patterns, over large areas in a cost effective and accessible manner. Maclaine et al showed that using the block copolymer technique to produce control‐disorder nanotopographies on thermoplastics was highly osteogenic and cost effective . Furthermore, the technique can be used to make templates through which Ti can be anodized selectively in a polymer domain, e.g., the P4VP in PS‐b‐P4VP block copolymer, to allow formation of the titanium oxide or titania patterns.…”