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Author:Elomaa, Laura
Title:Preparation of polycaprolactone based tissue engineering scaffolds by stereolithography
Polykaprolaktoniin pohjautuvien kudosteknologian tukirakenteiden valmistus stereolitografialla
Publication type:Master's thesis
Publication year:2009
Pages:(8+) 81      Language:   eng
Department/School:Elektroniikan, tietoliikenteen ja automaation tiedekunta
Degree programme:Bioinformaatioteknologian tutkinto-ohjelma
Main subject:Polymeeriteknologia   (Kem-100)
Supervisor:Seppälä, Jukka
Instructor:Korhonen, Harri ; Hakala, Risto
OEVS:
Electronic archive copy is available via Aalto Thesis Database.
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Location:P1 Ark S80     | Archive
Keywords:poly(epsilon-caprolactone)
tissue engineering
scaffolds
rapid prototyping
stereolithography
poly(epsilon-kaprolaktoni)
kudosteknologian tukirakenteet
pikavalmistusmenetelmät
stereolitografia
Abstract (eng): A novel photocrosslinkable and biodegradable resin was prepared for the use in a stereo lithography apparatus (SLA).
Three-branched poly(epsilon-caprolactone) (PCL) oligomers of five molecular weights were synthesized.
As the molecular weight of the oligomer increased, the melting point approached that of linear high molecular weight PCL (~ 60 C°).
To prepare photocrosslinkable polyester macromers , hydroxyl-terminated oligomers were methacrylated with methacrylic anhydride.
Photocrosslinkable poly(ester-anhydride) macromers were prepared by functionalizing hydroxyl-terminated oligomers with succinic anhydride and then methacrylating them with methacrylic anhydride.

The polyester macromers were photocrosslinked using ultraviolet light and Irgacure 2959 photoinitiator.
The crosslinking density increased as the molecular weigh of the macromer decreased.
The gel content was between 98,2 and 89,8 %.
Crosslinking increased the glass transition temperature by restricting the molecular mobility of polymer.
Young's modulus of the networks was between 15,4 and 6,7 MPa and the elongation at break between 19,3 and 78,5 %.
Cytotoxicity test showed good biocompatibility of the crosslinked networks.

Three-dimensional tissue engineering scaffolds were built by SLA using the molten polyester macromer, blue light and Irgacure 369 photoinitiator.
The scaffolds resembled the structures modeled by computer-aided design closely.
Any solvent was not used in SLA, and due to that, no material shrinkage was observed.
The average porosity was 70,5 % ± 0,8 %, when the designed porosity was 70 %.
More than 90 % of the pores were in the range of 350 to 550 µm in diameter, and the average pore size was 465 µm.
The pores were highly interconnected.
Low cytotoxicity of the crosslinked material along with the optimal pore architecture of the scaffolds indicates good applicability of the prepared PCL resin in a SLA building process.
Abstract (fin): Työssä valmistettiin uudenlainen valosilloitettava ja biohajoava hartsimateriaali, joka sopii ominaisuuksiltaan stereolitografiamenetelmään.
Aluksi syntesoitiin sarja poly(epsilon-kaprolaktoni) (PCL)-oligomeerejä viidellä eri moolimassalla.
Valosilloitettavat polyesterimakromeerit valmistettiin metakryloimalla hydroksyylipäätteiset oligomeerit metakryylianhydridillä.
Valosilloitettavat polyesterianhydridimakromeerit valmistettiin funktionalisoimalla ensin hydroksyylipäätteiset oligomeerit meripihkahappoanhydridillä ja tämän jälkeen metakryloimalla nämä happopäätteiset oligomeerit.

Polyesterimakromeerit silloitettiin sulamislämpötilan yläpuolella käyttäen ultraviolettivaloa ja Irgacure 2959 -initiaattoria.
Silloittumisaste oli korkein pienimmän moolimassan makromeerillä (98,2 %) ja alhaisin suurimman moolimassan makromeerillä (89,8 %).
Lasiutumislämpötila nousi silloittumisen myötä johtuen molekyylien liikkeen rajoittumisesta.
Silloitettujen näytteiden Youngin moduuli oli välillä 15,4 - 6,7 MPa pieneten makromeerin moolimassan kasvaessa.
Sytotoksisuustestit osoittivat silloitetun polymeerin olevan solujen kanssa bioyhteensopiva.

Stereolitografialla valmistettiin kolmiulotteisia kudosteknologian tukirakenteita käyttäen sulaa makromeeriä sekä sinistä valoa ja Irgacure 369 -initiaattoria.
Valmis rakenne jäljitteli tarkasti tietokoneella suunniteltua mallia.
Erillistä liuotinta ei tarvittu, minkä ansiosta materiaalin kutistumista ei havaittu.
Keskimääräinen huokoisuus oli 70,5 % ± 0,8 %, kun suunniteltu huokoisuus oli 70 %.
Yli 90 % huokosista oli halkaisijaltaan välillä 350 ja 550 µm, ja keskimääräinen huokoskoko oli 465 µm.
Optimaalisen huokosrakenteensa ja materiaalin suotuisten sytotoksisuustulosten ansiosta nämä kudostukirakenteet osoittavat soveltuvuutensa kudosteknologian käyttöön.
Työssä valmistettu biohajoava ja valosilloitettava PCL-hartsi laajentaa merkittävästi stereolitografian käyttömahdollisuuksia kudosteknologiassa.
ED:2010-02-11
INSSI record number: 38917
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