Advanced titanium scaffolds obtained by directional freeze-drying: on the influence of processing conditions

Ad anced i anium sca olds ob ained by di ec ional eeze-d ying: on he in luence o p ocessing condi ions Juan Pa ón1, Paloma T ueba2, José A. Rod íguez2, Yadi To es2, E Alonso3, A Hu ado2 and Da id Dunand4  1 Uni e si y o An ioquia, Bioenginee ing, G oup BAMR, Colombia  2 Uni e si y o Se ille, Ma e ials Enginee ing and T anspo , Spain  3 Uni e si y o Se ille, Analy ical Chemis y, Spain  4 No hwes e n Uni e si y, Ma e ials Science and Enginee ing, Uni ed S a es In oduc ion: Manu ac u ing o po ous ma e ials is one o he mos plausible ou es o add ess some impo an d awbacks o Ti implan s, like s ess shielding isks[3]. The manu ac u e o g aded ma e ials is an impo an goal, which has mul iple applica ions[2]. In his wo k, a no el de ice o manu ac u ing cylind ical po ous cp Ti, implemen ing di ec ional eeze cas ing has been de eloped[1]. The aim o his wo k was s udy he in luence o he empe a u e g adien imposed ( om -15, -10 and -5 °C o 20ºC) and he diame e o alumina ube used as a mold (8, 15 and 20 mm) on he di ec ional g ow h o dend i e ice and i anium powde compac ion. Ma e ials and Me hods: A c yogenic sal solu ion was used o cool he su ace o an aluminum cylinde (-15, -10 and -5 °C), on which he mix u e (cp Ti, dispe san and wa e ) was pou ed. The la e al ex e nal su ace o he ce amic cylinde con aining he mix u e was he mally isola ed. The uppe base was exposed o oom empe a u e (20 °C). Ice sublima ion was pe o med in a lyophilize o -50 °C and 0.070 mba o 24 h. Finally, po ous g een compac s (Fig.1) we e sin e ed a 1250 °C o 5h unde high acuum (~10-5 mba ). Physical cha ac e iza ion (A chimedes’ me hod), mic os uc u e (op ical mic oscopy and image analysis include: o al and in e connec ed po osi y, equi alen diame e , mo phology (aspec a io), and a e age size o he po es. Resul s and Discussion: The esul s o A chimede's Me hod ha e shown he ollowing indings: 1. In all cases, a highe diame e in he mold implies a lowe po osi y, wi h a highe densi y, which is consis en wi h he a e o solidi ica ion on because he e is a la ge con ac su ace wi h he aluminum ba . 2. In gene al, lowe g adien empe a u e shows a highe po osi y, wi h a lowe associa ed densi y. This phenomenon is ela ed o ha slow eloci y o solidi ica ion on , as well as wi h he easies ou e o ice dend i ic p og ession o push Ti pa icles ou o ice dend i es. 3. The bes balanced scena io seems o be o 15 mm and -10 ºC. Addi ionally, he esul s o Analysis Image ha e shown (Fig.2): 1. Acco ding o he heo e ical model, he op o he sample exhibi s a mo e elonga ed po osi y. 2. The mo phological pa ame e s o po es (Fig.3) seems o be ela ed no only wi h he diame e , bu also wi h he empe a u e o de cold su ace. I has been e alua ed o al po osi y(%), elonga ion ac o (F ), dis ance be ween po es (l) and majo and mino equi alen s diame e s (sizes majo axis and mino axis). 3. In gene al, he highe diame e o mold used, he lowe po osi y is ob ained, and he longe dis ance be ween po es and, which a e smalle and elonga ed. Conclusion: In his wo k, we we e able o implemen a new and simple p ocess o p oduce po ous Ti cilinde s wi h con olled and designed elonga ed po osi y. The eeze cas ing is a me hod e y sensi i e o composi ion o he ini ial slu y. Rega ding he in luence o he mold diame e on po es mo phological pa ame e s, i is no ed ha i educes he po osi y pe cen age, and elonga ed po es a e so e . This wo k was suppo ed by he Minis y o Science and Inno a ion o Spain unde G an No. MAT2010-20855.; This wo k was suppo ed by he Jun a de Andalucía (Spain) / FEDER (EU), h ough he p ojec Re . P12-TEP-1401. Re e ences: [1] Di ec ionally F eeze-cas i anium oam wi h aligned, elonga ed po es, Y. Chino, D. Dunand, Ac a Ma e ialia, 56 (2008) 105-113 [2] J. Cu ey, in Handbook o Bioma e ials P ope ies, ed. by J. H. Black, G. Has ings (Sp inge – Ve lag, London 1998), p. 3 [3] J. Banha , P og. Ma e . Sci., 46(6), 559-632 (2001) Keywo ds: hie a chy, ma e ial design, 3D sca old, Bone epai Con e ence: 10 h Wo ld Bioma e ials Cong ess, Mon éal, Canada, 17 May - 22 May, 2016. P esen a ion Type: Pos e Topic: Bioma e ials in musculoskele al o hopeadics and issues Ci a ion: Pa ón J, T ueba P, Rod íguez JA, To es Y, Alonso E, Hu ado A and Dunand D (2016). Ad anced i anium sca olds ob ained by di ec ional eeze-d ying: on he in luence o p ocessing condi ions. F on . Bioeng. Bio echnol. Con e ence Abs ac : 10 h Wo ld Bioma e ials Cong ess. doi: 10.3389/con .FBIOE.2016.01.03006 Recei ed: 28 Ma 2016; Published Online: 30 Ma 2016.