Eryn Zuiker Honors Portfolio

Eryn Zuiker\u27s honors portfolio captured in May 2020

Connective Tissue Infiltration into Three-Dimensional Sintered Cobalt Chrome Alloy

The biomaterial used in medical implantable devices must sufficiently integrate within the biological system and be compatible with surrounding tissue. In this study, cobalt chrome (CC) will be utilized, offering high biocompatibility while minimizing immune reactivity. CC will be used in conjunction with Hydroxyapatite (HA), a bioactive material that is an essential component of normal bone and teeth. HA\u27s bioactivity leads to high biodegradation when implanted alone, which can result in clinical implant failure. In our study, we will test the biocompatibility of a mixture alloy, fabricated using a three-dimensional printer.  To test the biocompatibility of the fabricated metal implant in-vivo, one-by-two-by-four millimeter metal pieces (20% HA, 80% CC) mixture alloys will be inserted on rat skulls through a small incision made via sterilized surgery. After five weeks, the implants and surrounding tissue will be removed and observed using scanning electron microscopy. The surrounding connective tissues will be examined for inflammation and other signs of tissue damage or rejection. We hypothesize that the metal alloys will be encapsulated by dense connective tissue continuous with the periosteum and will show no signs of inflammation or rejection. Furthermore, connective tissue will infiltrate into spaces within the alloy, between and around the alloy spheres to form a dense matrix of cellular and fibrous material throughout the implant. These findings will help contribute to the science of medical implantation and tissue rejection and improve our understanding of medical device alloys used for hip, femur and other implants

Biocompatibility of Hydroxyapatite and Cobalt-Chrome Alloys

The biomaterial used in medical implantable devices must be able to sufﬕciently integrate within the biological system and remain compatible with surrounding tissue. Previously, Stainless Steel was explored. Cobalt Chrome (CC) will now be utilized due to higher biocompatibility while minimizing immune response and rejection. Hydroxyapatite (HA), a bioactive material that is a major and essential component of normal bone and teeth, is often used for coating metal implants to initiate infiltration. However, its bioactivity leads to high biodegradation when implanted alone, which can result in clinical implant failure. In the present study, our focus is on the biocompatibility of a mixture alloy of stainless steel and hydroxyapatite, fabricated by using a three-dimensional printer. To test the biocompatibility of the fabricated metal implant in vivo, one millimeter-sized metal pieces of high and low HA ratio mixture alloys were inserted on rat skulls through a small incision on the back made using a sterilized implantation surgery. After four months, the metal pieces were removed and observed under scanning electron microscopy to determine the degree of infiltrated bone and connective tissue. The surrounding connective tissues were also examined for inflammation and other tissue damages. The result showed that, the metal alloys that were fixed on the bone were encapsulated by dense connective tissue continuous with the periosteum without having any signs of inflammation or rejection. Furthermore, the connective tissue infiltrated into spaces within alloy, between and around the spheres of cobalt chrome, and formed a dense matrix of cellular and fibrous material throughout the implant. As further study, an implant using CC and HA with various particle bond strength will be implanted for better infiltration of bone growth and formation of vessel. Our findings will help improve medical device alloys for hip, femur and other implants