We have developed a combinatorial method for determining optimum tissue scaffold composition for imaging by X-ray techniques. X-ray radiography and microcomputed tomography enable non-invasive imaging of implanted materials in vivo and in vitro, respectively. However, highly porous polymer scaffolds do not always provide good X-ray contrast and can be difficult to image with X-ray-based techniques. Incorporation of high radio contrast atoms, such as iodine, into the polymer structure improves X-ray radiopacity but also affects physicochemical properties and material performance. Thus, we have developed a gradient library approach to efficiently determine the minimum amount of contrast agent necessary for X-ray-based imaging.The combinatorial approach is demonstrated in a polycarbonate scaffold system where X-ray imaging of poly(desaminotyrosyl-tyrosine ethyl ester carbonate) (pDTEc) scaffolds is improved through blending with iodinated-pDTEc (pI2DTEc). The results show that pDTEc scaffolds must be doped with at least 9 %, 16 %, 38 % or 46 % pI2DTEc to enable effective imaging by microradiography, dental radiography, dental radiography through 0.75 cm of muscle tissue or microcomputed tomography, respectively. Only two scaffold libraries were required to determine these minimum pI2DTEc percentages required for X-ray imaging, which demonstrates the efficiency of this new combinatorial approach for optimizing scaffold formulations.
Pub Type: Journals
combinatorial library, polycarbonate, radiopacity, scaffolds, X-ray microcomputed tomography, X-ray radiography