Shape control and orientation of HBM Cells on micropatterned coatings

Introduction:

Combining sol-gel and microfabrication techniques provides an alternative to generate model surfaces to study topographical modulation of cell-biomaterial interactions.

Objectives:

To evaluate how surface topography affects the morphology and alignment of Human Bone Marrow (HBM) cells cultured In Vitro on micro-patterned (micro-PGC) and flat glass coatings (FGC) produced by sol-gel processing.

Materials and Methods:

Photolithography was used to produce master patterns of parallel lines and pillars with microscale dimensions. A polydimethylsiloxane (PDMS) mold was obtained from the masters by uniformly mixing PDMS (Silastic T-2, Dow Corning, USA) with a curing agent, pouring the mixture onto the masters, degassing, and curing. The mold was used to print SiO₂ glass coatings produced by a sol-gel process. The coatings were then sintered and sterilized.

In vitro biological evaluation was conducted using HBM cells, cultured with a standardized protocol for four days. Cell morphology and orientation were observed using scanning electron and optical microscopy.

Results:

Flat and MPGC with lines and pillar shaped features with 5µm periodicity and ~3µm height were produced.

Cells presented a normal morphology on flat surfaces while slimmer, preferential orientation and more elongated morphologies could be seen on both the line and pillar micro-patterned surfaces.

HBM cells cultured on flat glass coatings showed spreading and more random proliferation as compared to the cells on the micro-patterned glass coatings.

Micro-patterned glass coatings with pillar shaped features showed lower orientation control than line shaped micro-patterned glass, but higher than flat glass coatings. A number of cells on the pillar surface presented an interesting and peculiar behavior. Cells stretched long distances, often more than 100µm, in one specific direction to reach and connect with other cells.

Conclusions:

These preliminary studies revealed that Micro-PGC controlled the orientation of HBM cells and induced significant changes in their morphology.

Acknowledgment:

Program-Alban/E05D050652CO, FCT/SFRH/BD/36220/2007 and FCT/POCI/SAU-BMA/56061/2004.