Biocompatibility of Sapphire and Borosilicon Glass Using Combined MRI and Histology

Kaushik S Parthasarathy

Aim of the Research

• We developed a Protocol to investigate the short and long term neuro compatibility of novel and traditional Biomaterials that could be used in Neural Prosthesis

• Wafers of Sapphire and BSG (2.5mm dia. x 0.250mm thick) were implanted unilaterally onto the surface of the parietal cortex using aseptic techniques in rats and imaged using MRI (4.7T Animal Magnet)

Experiments….

• The animals were allowed to survive for 28 days • Sham – operated and mechanically – lesioned animals served as

controls

• MRIMRI Pre and Post implantation (10, 28 days) MRI was performed

using Spin Echo and Gradient Echo Sequence, on sham, +ve control and implanted animal

Assessment of Inflammation, Edema and Tissue interference with the implant was done using MRI

• HistologyHistology Tissue underlying the implant was stained for degenerating

axons and neurons using Nissl, Silver, GFAP for reactive astrocytes stains

Results

10th Day 28th Day

Sham

10th Day 28th Day

Histology

Nissl Stain

Sapphire Implant

10th Day 28 th Day

Histology

Nissl Stain GFAP Silver

Future Directions

• Surface modification is done in order to enhance the biocompatibility of the materials

“GOAL”

• The overall goal of the project is to provide comprehensive evaluations of materials and neural implants in the most appropriate (in the retina and the brain where the structures will be implanted for treatment or diagnoses) setting.

Acknowledgements

• Michigan Life Science Corridor (MLSC) for funding the Research• E.Mark Haacke• Dr.Pat McAllister• Dr.G.Auner• Dr.Norman Cheng• Yimin Shen• Jie Li• Kelley Barbant