Computed tomography technologies to measure key structural features of polymeric biomedical implants from bench to bedside

• Published in: Journal of biomedical materials research. Part A Vol. 112; no. 11; pp. 1893 - 1901
• Main Authors: Pawelec, Kendell M., Schoborg, Todd A., Shapiro, Erik M.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.11.2024; Wiley Subscription Services, Inc
• Subjects: Animals; Biocompatible Materials - chemistry; biomedical devices; Biopolymers; Computed tomography; Contrast agents; Contrast media; Contrast Media - chemistry; Devices; Feasibility studies; Humans; Information systems; medical imaging; Nanoparticles; Nanoparticles - chemistry; Polymers; Polymers - chemistry; Pore size; Porosity; Prostheses and Implants; Regeneration (physiology); Surgical implants; Tissue engineering; Tomography; Tomography, X-Ray Computed - methods; Translation; Wall thickness; X-Ray Microtomography; computed tomography; biomedical devices; porosity; medical imaging
• ISSN: 1549-3296; 1552-4965; 1552-4965
• DOI: 10.1002/jbm.a.37735

Implanted polymeric devices, designed to encourage tissue regeneration, require porosity. However, characterizing porosity, which affects many functional device properties, is non‐trivial. Computed tomography (CT) is a quick, versatile, and non‐destructive way to gain 3D structural information, yet various CT technologies, such as benchtop, preclinical and clinical systems, all have different capabilities. As system capabilities determine the structural information that can be obtained, seamless monitoring of key device features through all stages of clinical translation must be engineered intentionally. Therefore, in this study we tested feasibility of obtaining structural information in pre‐clinical systems and high‐resolution micro‐CT (μCT) under physiological conditions. To overcome the low CT contrast of polymers in hydrated environments, radiopaque nanoparticle contrast agent was incorporated into porous devices. The size of resolved features in porous structures is highly dependent on the resolution (voxel size) of the scan. As the voxel size of the CT scan increased (lower resolution) from 5 to 50 μm, the measured pore size was overestimated, and percentage porosity was underestimated by nearly 50%. With the homogeneous introduction of nanoparticles, changes to device structure could be quantified in the hydrated state, including at high‐resolution. Biopolymers had significant structural changes post‐hydration, including a mean increase of 130% in pore wall thickness that could potentially impact biological response. By incorporating imaging capabilities into polymeric devices, CT can be a facile way to monitor devices from initial design stages through to clinical translation.