Using ex Ovo Chick Chorioallantoic Membrane (CAM) Assay To Evaluate the Biocompatibility and Angiogenic Response to Biomaterials

Biomaterials need to be vigorously tested at every stage of preclinical development. As demand for in vivo culture environments continues to increase, traditional animal models are often technically complex, ethically undesirable, time-consuming, and resource intensive and thus present a barrier to high throughput screening. The chick chorioallantoic membrane (CAM) assay has long been used to study the effects of drugs on angiogenesis in vivo, providing researchers with a readily available, accessible, self-sustaining, and high throughput screen without requiring animal facilities. It has also been recognized as an in vivo assay to test initial tissue response to biomaterials; however it has not yet gained widespread acceptance. This could be due to lack of specific protocols on how to optimize this assay to specifically test biomaterials. Here we describe how the ex ovo (shell-less) CAM assay can be effectively used to study the angiogenic potential and initial tissue response to biomaterials. In comparison to alternative in vivo approaches, this technique provides additional advantages to the researcher as it allows better visualization of implanted biomaterials and the ability to implant several samples simultaneously enabling combinatorial biomaterial assays to be conducted.