Poly 1,8-Octanediol Citrate Breast Biopsy Scaffold and Deployment System

During a breast biopsy, it is crucial to accurately identify regions of concern and deliver markers accurately for subsequent imaging and surgical procedures. If surgical removal is not required, it is essential for the marker to be biocompatible, as it will remain in the tissue for the remainder of the patient's lifetime. Current breast biopsy systems employ a forceful deployment during marker administration leaving a void within the tissue that contributes to marker migration. Furthermore, current marker-encapsulating-meshes are not robust and lack compliance to breast tissue which further contributes to rapid mesh disintegration and marker migration.<br/><br/>To address the aforementioned problems present in the current standard of care, our group developed a three-pronged approach consisting of the creation of an elastic biodegradable scaffold to encapsulate the marker, a deployment device for <i>in vivo </i>testing on rats that does not utilize forces during administration, and a transparent breast tissue phantom to determine real-time expansion of the scaffold.<br/><br/>First, a biodegradable Poly 1,8-Octanediol co-citrate (POC) elastic scaffold capable of securing both metallic and non-metallic markers was developed and characterized. Our initial results indicate that POC’s properties can be tuned to user-preference by changing crosslinking time, porogen size and leaching time during fabrication; to ensure elasticity of the scaffold, we optimized the pore size by using 400μm NaCl as a porogen. Next, we optimized POC compression and expansion by testing tensile forces at different crosslinking and porogen leaching times. Interestingly, we encountered that during subsequent crosslinking after leaching, POC develops limited self-healing capabilities which allowed for previously embedded markers to be repositioned within a completed scaffold.<br/><br/>Secondly, we developed a 3D-printed deployment device which releases the encapsulated breast biopsy marker passively in a retractable motion, eliminating the forces that cause an increase in void size within the biopsy incision. The device was subsequently employed during <i>in vivo </i>testing in rats, from which initial results demonstrate little to no marker migration when compared to current standard of care.<br/><br/>Finally, an optically transparent breast phantom was made from Dermasol. This reusable, insensitive to temperature or dehydration phantom allows for POC scaffold deployment and expansion in real time.<br/><br/>Here we presented our solutions to address the challenges associated with breast biopsy marker placement. We achieved this by developing a biodegradable POC scaffold capable of encapsulating markers and expanding to fill the biopsy void, a retractable deployment device to release the scaffold passively, a breast tissue phantom for visualization of sponge expansion, and tested of our approach <i>in vivo</i>. We are currently determining POC’s degradation profile as well as continuing to evaluate our prototype scaffold and deployment system <i>in vivo </i>to measure the reduction in metallic marker migration compared to commercially available devices.