title: Photopolymerizable hydrogels for implants: Monte-Carlo modeling and experimental in vitro validation.
abstract: Photopolymerization is commonly used in a broad range of bioapplications, such as drug delivery, tissue engineering, and surgical implants, where liquid materials are injected and then hardened by means of illumination to create a solid polymer network. However, photopolymerization using a probe, e.g., needle guiding both the liquid and the curing illumination, has not been thoroughly investigated. We present a Monte Carlo model that takes into account the dynamic absorption and scattering parameters as well as solid-liquid boundaries of the photopolymer to yield the shape and volume of minimally invasively injected, photopolymerized hydrogels. In the first part of the article, our model is validated using a set of well-known poly(ethylene glycol) dimethacrylate hydrogels showing an excellent agreement between simulated and experimental volume-growth-rates. In the second part, in situ experimental results and simulations for photopolymerization in tissue cavities are presented. It was found that a cavity with a volume of 152  mm3 can be photopolymerized from the output of a 0.28-mm2 fiber by adding scattering lipid particles while only a volume of 38  mm3 (25%) was achieved without particles. The proposed model provides a simple and robust method to solve complex photopolymerization problems, where the dimension of the light source is much smaller than the volume of the photopolymerizable hydrogel.
authors.affiliation: Swiss Federal Institute of Technology Lausanne, Microengineering Institute, Laboratory of Applied Photonics Devices, station 17, Lausanne 1015, SwitzerlandbSwiss Federal Institute of Technology Lausanne, Institute of Bioengineering, Laboratory of Biomecha.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schmocker
authors.affiliation: Swiss Federal Institute of Technology Lausanne, Institute of Bioengineering, Laboratory of Biomechanical Orthopedics, station 19, Lausanne 1015, SwitzerlandcSwiss Federal Institute of Technology Lausanne, Institute of Materials, Laboratory of Polymer and.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Khoushabi
authors.affiliation: Centre Hospitalier Universitaire Vaudois, Orthopedic Department, Avenue P. Decker 4, Lausanne 1011, Switzerland.
authors.forename: Constantin
authors.initials: C
authors.lastname: Schizas
authors.affiliation: Swiss Federal Institute of Technology Lausanne, Institute of Materials, Laboratory of Polymer and Composite Technology, station 12, Lausanne 1015, Switzerland.
authors.forename: Pierre-Etienne
authors.initials: PE
authors.lastname: Bourban
authors.affiliation: Swiss Federal Institute of Technology Lausanne, Institute of Bioengineering, Laboratory of Biomechanical Orthopedics, station 19, Lausanne 1015, Switzerland.
authors.forename: Dominique P
authors.initials: DP
authors.lastname: Pioletti
authors.affiliation: Swiss Federal Institute of Technology Lausanne, Microengineering Institute, Laboratory of Applied Photonics Devices, station 17, Lausanne 1015, Switzerland.
authors.forename: Christophe
authors.initials: C
authors.lastname: Moser
mesh_terms: D001672:Biocompatible Materials; D006801:Humans; D007403:Intervertebral Disc; D008422:Materials Testing; D008689:Methacrylates; D008954:Models, Biological; D009010:Monte Carlo Method; D055668:Photochemical Processes; D011092:Polyethylene Glycols; D058105:Polymerization; D019736:Prostheses and Implants; D015203:Reproducibility of Results
chemical_list: D001672:Biocompatible Materials; D008689:Methacrylates; C421283:poly(ethylene glycol)-dimethacrylate; D011092:Polyethylene Glycols