title: Ultrasonic monitoring of foamed polymeric tissue scaffold fabrication.
abstract: Polymeric tissue scaffolds are central to many regenerative medicine therapies offering a new approach to medicine. As the number of these regenerative therapies increases there is a pressing need for an improved understanding of the methods of scaffold fabrication. Of the many approaches to processing scaffolds, supercritical fluid fabrication methods have a distinct advantage over other techniques as they do not require the use of organic solvents, elevated processing temperatures or leaching processes. The work presented here is centred on the development of a new approach to monitoring supercritical scaffold fabrication based on determination of the scaffold acoustic impedance to inform protocols for scaffold fabrication. The approach taken uses an ultrasonic pulse-echo reflectometer enabling non-invasive monitoring of the supercritical environment on-line. The feasibility of this approach was investigated for two scaffolds of different molecular weight. Acoustic results demonstrate that differences in the physical properties of the two scaffolds could be resolved, particularly during the foaming process which correlated with findings from time-lapsed imaging and micro X-ray computed tomography (micro X-ray CT) images. Thus, this work demonstrates the feasibility of ultrasonic pulse-echo reflectometry to non-invasively study supercritical scaffold fabrication on-line providing a greater understanding of the scaffold fabrication process.
authors.affiliation: School of Electrical and Electronic Engineering, University of Nottingham, University Park, Nottingham, Nottinghamshire NG7 2RD, UK. melissa.mather@nottingham.ac.uk
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Mather
authors.forename: John A
authors.initials: JA
authors.lastname: Crowe
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Morgan
authors.forename: Lisa J
authors.initials: LJ
authors.lastname: White
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Kalashnikov
authors.forename: Vladimir G
authors.initials: VG
authors.lastname: Ivchenko
authors.forename: Steven M
authors.initials: SM
authors.lastname: Howdle
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Shakesheff
mesh_terms: D000162:Acoustics; D001672:Biocompatible Materials; D004867:Equipment Design; D008422:Materials Testing; D008970:Molecular Weight; D011100:Polyglycolic Acid / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D044968:Regenerative Medicine / Q000295:instrumentation; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*; D014057:Tomography, X-Ray Computed / Q000379:methods; D014465:Ultrasonics
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D012997:Solvents; D011100:Polyglycolic Acid