TAP CHI HOA HOC T. 50(6) 699-703 THANG 12 NAM 2012
NGHIEN CU'U DI^N Bl^N DIEN HOA C O A V A T LIEU HAp/THEP KHONG Gi 316L TRONG DUNG mCH MO P H 6 N G DICH CO TH^ NGU'ai
Pham Thi Nam'*, Nguyen The Huyen', Tran Dai Lam^ Dinh Thi Mai Thanh' Vi4n Ky thugt nhi^t ddi. Vi?n Khoa hgc va Cdng nghe Vi('t Nam
^Vi?n Khoa hgc Vdt liqu, Vi^n Khoa hgc vd Cong ngh? Vi^l Nam Den Tda soan 20-4-2012
Abstract
Electrochemical behavior of HAp/3l6L stainless steel materials in solution simulated body fluid according to immersion time was studied by measurement of open circuit potential (Eo), Tafel polarization and electrochemical impedance methods. The results were shown that the deviation of Eo, polarization resistance (Rp) and corrosion current (icon) were formed according to time because there is always the formation of apatite film and dissolved HAp coating in the test. SEM image of (he sample surface HAp/316L stainless steel showed the formation of apatite film with coral shape.
Keywords: HAp/316 stainless steel, SBF, apatile.
I. MO DAU
Hydroxyapatit la mudi kep ciia tri-canxi photphat va canxi hydroxit, trong ty nhien tdn tai dudi dang fio-apatit Caio(P04)6F2. Nd la thanh phan vo CO chinh trong xuong va rang ngudi va hien dang trd thanh ddi tugng nghien cuu chinh ciia cac nha khoa hpc nham muc dich cai thien cac tinh chat sinh hpc, hoa hpc ciia nd. Hydroxyapatit (HAp) thudng dugc sir dung dudi dgng bpt lam thudc bd sung canxi, dang gdm xdp dk. thay the xuong hogc dang mang phii len be mat kim loai de tang kha nang tucmg thich cua vat lieu cay ghep [1-6]. Thep khdng gi 316L(TKG316L) dugc sir dung nhieu trong phau thugt chinh hinh, dgc bipt la trong cdng nghe lam rang bdi vi nd cd modul dan hdi thap, dp tuang thich sinh hpc va dg b6n an mdn cao trong mdi trudng sinh iy. Tuy nhien, TKG3I6L la mdt vat lipu tra, khdng de hinh thanh lien Vk hda hgc mgnh me vdi xuong ty nhien. Vi vgy, viec nghien ciru tdng hgp mang hydroxyapatit tren nen TKG3I6L nham cai thien sy lien ket vdi xuong ty nhien ciia vgt li?u cdy ghep cung nhu nang cao kha nang bao vp chdng an mdn cho thep khdng gi trong mdi trudng sinh hpc cua CO the ngudi.
Bai bao nay gidi thi$u k^t qua do dien the mach hd, phan eye Tafel, tdng trd dien hda ciia vat lieu HAp/TKG316L theo thdi gian ngam trong dung djch md phdng dich ca th6 ngudi (SBF). Sy hinh thanh
mang apatit dugc the hien bdi hinh anh kinh hien vi dien tuquet.
2. THUC NGHIEM
Mang HAp tdng hgp tren TKG316L bang phuang phap quet the trong khoang 0 den -1,6 V/SCE (5 vdng vdi tdc dp quet 5 mV/s) trong binh dien hoa 3 dien cue (dien eye lam viec TKG316L, dien eye ddi platin (Pt), dien eye so sanh calomen bao hoa KCI) cd chira 80 ml dung dich:
Ca(NO3)2.4H2O3xl0'^M+NH4H2PO4l,8xl0"^M + NaN03 0,15 M + H2O2 6% (khdi lugng), tai nhiet do 70T.
Mau TKG316L diing trong thi nghiem tdng hgp mang HAp cd kich thudc 1x10x0,2 cm cd thanh phdn: 0,3% Al; 0,22% Mn; 0,56% Si; 17,98% Cr;
9,34% Ni; 2,15% Mo; 0,045% P va 69,45% Fe, dugc danh bdng ca hpc bang giay nham logi 320, 400 (ciia Trung Qudc) va giay nham tinh loai 600, 800, 1200 (ciia Nhgt Ban), sau do rira sach mau vdi nudc cdt, trang lgi bang cdn, dfi khd va diing epoxy de gidi hgn dipn tich lam viec 2 cm^.
Dung djch mo phdng djch ca the ngudi SBF (Simulated Body Fluid) dugc pha tir cac hda chat cd dp tinh khiet cao vdi thanh phan dugc chi ra tren bang 1, pH = 7,35 dugc dieu chinh bang dung dich NaOH 1 M, dung djch trong sudt va khdng cd ket tiia hay vdn due, dugc bao quan d nhiet dp phdng [8, 9].
TCHH,T. 50(6), 2012
Bang I: Thanh phan cua 1 lit dung djch SBF
Ph(im Thi Nam vd cpng si,
Muoi Nong dp (g/L)
NaCI 7,996
NaHCO, 0,350
KCI 0,224
Kjl-lPOj.aHjO 0,228
M K C I , . 6 H , 0
0,305
CaCb 0,278
NaiSO, 0,071 "
Cac thi nghiam khao sat sy tuang thfch ciia vgt lieu HAp/TKG316L trong dung djch SBF dugc thyc hipn trong binh dipn hda cd the tich 80 ml, d :ihi^t dp 37"C vdi 3 dipn eye: dipn eye lam vipc la mau HAp/TKG316L cd di^n tich lam vipc 2cm^ dipn eye ddi Pt va dipn eye so sanh la calomen bao hda KCI.
Qua trinh phan eye dipn the trong khoang ± 10 mV xung quanh dipn the mgch hd Iheo ihdi gian ngam mau, vdi toe dp quet the I mV/s. Tdng trd dipn hda dupc do tgi dipn the mach hd trong khoang tan sd 10^ Hz den 10 mHz vdi bicn dp the ±10 mV. Qua trinh tdng hgp HAp, do phan eye Tafel va ldng trd dien hoa dugc thyc hipn tren may Polenliostat Autolab PGSTAT 30 (Ha Lan). Sy bicn doi pH cua dung djch theo ihdi gian ngam mau HAp/TKG316L trong SBF dugc xac djnh tren may PIIM2I0.
3. KET QUA vA THAO LUAN
3.1. Xac dinh pH cua dung djch SBF va dien the mach hd ciia HAp/TKG3I6L trong dung dich SBF theo thd1 gian ngam mau.
Sy bien ddi pH ciia dung djch SBF va dien th6 mach hd Eo theo thdi gian ngam mau HAp/TKG316L dugc gidi thieu tren hinh 1. Gia tri pH d thdi diem trudc khi ngam (t =0) la 7,37 tuong ty nhu pH trong huyet tuong ciia ca the ngudi.
Trong 7 ngay dau ngam mau pH tang dan theo thdi gian va dat gia tri eye dai 7,55 sau 7 ngay ngam, gia tri pH nay cao hon mpt chiit so vdi pH ciia huyet tuang trong co the ngudi nhung khdng lam hai co the. Sy tang pH cd the giai thfch do sy tfch ty ciia ion OH tren hk mat mdu HAp/TKG316L. Vdi thdi gian ngam mau dai han 7 ngay, pH lai giam xuong va dat gia trj dn dinh d 7,4 gan nhu luong duong vdi pH ban dau sau 14 va 17 ngay ngam mau.
Khi vat lieu HApArKG3t6L dugc ngam Irong dung dich SBF, ion canxi trong dung dich SBF tang ien bdi sy hda tan cua HAp iren be mat va ngay sau dd OH' dugc tich i\t tit tir bdi vi cd sy trao ddi Ca'*
va W, ket qua nay ddn den pH tang. Sy tich ly ion OH' tren be mat mau la ygu td quan trpng de hinh thanh mam tinh the apatit [6]. Dpng hpc ciia qua trinh hinh thanh apatit tren be mat HAp/TKG316L chia lam hai giai doan: giai dogn thu nhdt la qua trinh hda tan mang HAp, giai dogn thir hai la sy hinh thanh mang apatit tren be mat. Theo tai lieu tham khao, thanh phdn Ca-P bj ket tiia khi pH cua dung djch Idn hem 7,4. Trong giai dogn tilp theo ion canxi
va phdtpho bj tiSu thy mOt lugng ldn do sy tgo thanh mpt lugng du thira apatit vk dong thdi ion OH" cung bj tieu thg tucmg ung do dd dan den pH cua dung djch SBF giam. Khi can bdng giu-a sy hda tan vasit kel tiia apatit dugc thiet lgp thi gia trj pH khdng thay doi nii'a.
Doi vdi dipn the mgch hd, tai thdi diem dau tien ngam mau dipn the mgch hd cd gia trj -12S mV/SCE, sau 5 ngay ngam mau dipn the giam rat nhanh vc phia am va dgt gia trj eye tieu -299 mV/SCE, ngay sau dd dipn the lgi tang len den gia trj -155 mV/SCE nhung d thdi gian 10 va 14 ngay ngam mau, dipn the lgi giam xudng (-261 mV/SCE), cuoi ciing sau 17 ngay ngam mau dipn the cd gia trj -
174 mV/SCE. Nhin chung ddi vdi mlu HAp/TKG316L, dipn the mgch hdcd sy thang giang mgnh theo thdi gian ngam mau trong SBF. Ket qua nay cd the dugc giai thich do sy hda tan va hinh thanh mang apatit tren n6n HAp/TKG316L, hoan toan phii hgp vdi ket qua do pH ciia dung djch SBF.
Thdi gian (ngiy)
Htnh I: Sy biSn doi pH ciia dung djch SBF (1) va dipn the mgch hd (2) theo thdi gian ngam mdu
HAp/TKG3l6L 3.2. Do phan eifc Tafel
Hinh 2 bieu diln dudng cong phan eye d?ng Tafel cua HAp/TKG3I6L d nhirng thdi gian ngam mau khac nhau va hinh 3 la bi6n ddi mat dp dong an mdn (ijorr), "Jipn trd phan eye (Rp) thu dugc tir phan tich dudng Tafel. Tir hinh 3 cho thay, mgt dp dong an mdn va thd an mdn ciia mdu HAp/TKG316L bien ddi thang giang lien tyc sau 17 ngay ngam mau.
Trong 5 ngay ddu ngam mlu mgt dp ddng an mon tang va dgt gia trj 0,36 ^A/cm^ sau dd giam vH^t gia tri thdp nhdt d 8 ngay ngam (0,07 pA/cm^), tifS
700
TCHH,T. 50(6), 2012
ddn 14 ngay mat dp ddng lgi tang d8n 0,23 pA/cm^
va lgi giam di d thdi gian 17 ngay ngam (0,077 pA/cm^). Sy bien ddi thang giang ciia mat dp ddng an mdn hoan toan phii hpp vdi bien doi dipn the mgch hd theo thdi gian.
3.3. Do tong trd di|n hoa
De khang djnh ket qua thu dugc bdng phucmg phap do dien the mach hd va mgt dp ddng an mdn theo thdi gian ngam mau trong dung djch SBF, chung tdi da tiSn hanh do tdng trd dien hda tai dipn
Nghien cuu dien bien di^n hoa...
the mgch hd. Hinh 4 gidi thipu pho tdng trd dang Bode cua HAp/TKG316L trong dung dich SBF d nhCrng thdi gian ngam mau khac nhau.
Sy bien ddi thang giang ciia tdng trd theo thdi gian ngam mau dugc th6 hipn tren hinh 4a. Gian do bieu dien sy thay ddi gdc pha dudng nhu chi bao gdm mpt thanh phan dipn dung d tan so thap dgc trung cho mang HAp (hinh 4b). Ket qua nay cd the dugc giai thfch trong qua trinh tdng hprp HAp bang phuang phap quel the catdl da lam hu hdng mdt phdn mang thy dpng tren nen TKG316L.
E(V/SCE)
Hinh 2. Dudng cong phan eye dgng Tafel ciia HAp/TKG316L theo thdi gian ngam mau trong SBF
Htnh 3: Sy bien ddi i.^,, va Rp cua HAp/TKG316L theo thdi gian ngam mau trong dung djch SBF
4 5 - 4 . 0 - 3.5-
"S 2 5 - o
2 0 - 1 5- 1.0- (a)
T ^ ,
' ^ ^
' ^ ^ S s
^
-2 0
— 0 ngay
—*— 1 ngay
—•— 3 ngSy
—-^^ 5 ngay
—«— 8 ngSy
—D— 10ngSy
—T— 14 ngay
—•—17 ngay
^ f e i l
2 4 6 lb)
—••^OngSy —•—BngSy
—•—Ingdy —°—lOngSy
— ' ^ S n g S y —•—14ng&y
•—°—5ngSy —»—ITng^y
h 4: Phd tdng trd dang Bode cua mlu HAp/TKG316L trong dung djch SBF d nhirng thdi gian ngam mau khac nhau: (a) logl Zl theo logfva (b) gdc pha theo logf
Bk theo doi sy biSn ddi dien trd mang thy ddng, dien trd mang apatit ciia mau HAp/316L trong dung djch SBF, gia tri modun tdng trd d tdn sd 1 kHz va IHz vdi nhirng thdi gian ngam mau khac nhau da dugc xac dinh (hinh 5). Vdi tdn so I kHz dac trung cho mang mdng thy dpng tren TKG316L (hinh 5a).
6 thdi di8m ddu tien modun tdng trd cd gia tri
khoang 20Q, sau 3 ngay ngam mau, modun tdng trd tang lien tyc va dat gia trj 36,50, dieu nay chimg td mang thy dpng cd xu hudng ngay cang xit chat, sau dd modun tdng trd giam d 5 ngay ngam mau cd the do sy tan cdng ciia cac anion gay an mdn cd mat trong dung djch SBF nhu CF, sau 8 va 10 ngay ngam mau, modun tdng trd lgi tang nhung d 14 va 17 ngay
TCHH,T. 50(6), 2012
modun tong trd giam. Ket qua nay cho thdy qua trinh bien doi mang thy dpng trong dung djch SBF cung kha phuc tap.
Ct tdn so IHz (hinh 5b) dgc trung cho sy hinh thanh mang apatit va hda tan mang HAp ciia mau
Phgm Thi Nam vd cgng stf HAp/TKG316L. Trong 5 ngay dau ngam mlu modun tong trd cua mlu HAp/TKG316L cd xu hudng giim, sau dd bien doi thang giang, d^c tnmg cho qua trlnh hda tan va ket tua ion canxi tren bi
Thdi gian (ngay)
LFinh 5 Sy bicn ddi modun ldng trd cua mau HAp/TKG316L d lan so I kHz (a) va I Hz (b) theo thdi gian ngam mau trong dung dich SBF
3.4. Co che hinh thanh mang apatit tren HAp/TKG316L trong SBF |6, 7]
Dpng hgc ciia qua trinh hinh thanh mang apatit tren be mat mau HAp/TKG316L dugc chia lam hai qua trinh: thir nhat la qua trinh hoa tan mang HAp va Ihir hai la qua trinh ket tiia apatit tren be mat mau.
Sy hinh thanh apatit duac dien ra theo phan img sau:
lOCa^' + ePOj-'" + 20H- ^ Ca,o(P04)6(OH);
lOCa^* + (6-x) P04^" + 20H" + xCO^^- ^ Ca,o(PO,)6.,(C03),(OH), Qua trinh hda tan mang I lAp dan den ndng dp ion canxi trong dung djch SBF tang. Mat khac ion canxi va photphat bj tieu hao bdi sy tgo mdm va phat
Irien linh the apatit. Sau dd tdc dp hda tan ciia HAp giai phdng ion canxi ldn ban nhieu so vdi toe dp ket tiia mang apatit. Vdi thdi gian ngam mau dai hem, tdc dp hda tan va tdc dp ket tiia ciia ion canxi se dat tdi trang thai can bang.
3.5. Phan tich hinh thai hpc ciia mang apatit hlnb thanh tren HAp/TKG316L
Hinh 6 la hinh anh SEM ciia mau HAp/TKG3l6L sau 17 ngay ngam trong dung djch SBF. Tren be mat cd the quan sat thay sy hinh thanh mang apatit. 6 dp phdng dgi ldn 50 nghin hogc 100 nghin lan cd the quan sat thay tinh the apatit hirh ihanh irong SBF cd hinh san hd va cd kich thuoc nano.
Hinh 6: Hinh anh SEM cua mlu HAp/TKG316L trong dung djch SBF sau 17 ngay ngam mlu
T C H H , T . 50(6), 2 0 1 2 4. K E T L U A N
Dien bien dien hda c u a vat lipu H A p / t h e p k h d n g gi 316L trong d u n g dich S B F d nhipt dp 37°C da cho thay d p n g hpc ciia sy h i n h thanh m a n g apatit xay ra ddng thdi vdi q u a trinh h d a tan m a n g H A p d o d o cac gia trj dipn t h e mgch h d Eo, Rp va icoir bien ddi thang giang t h e o thai gian n g a m . Nhii'ng ket q u a nay cung d u g c k h a n g djnh bdi s y bien ddi cua modun tdng t r d d tan sd I H z . Tren be m a t vgt lipu H A p / T K G 3 1 6 L cd kha n a n g hinh thanh m a n g apatit trong d u n g dich m d p h d n g djch c o th6 ngudi d u g c the hien q u a hinh anh S E M . Ket qua nay m d ra trien vpng d n g d u n g H A p / T K G 3 1 6 L lam vgt lipu cay ghep x u a n g thay t h e cho n h d n g vgt lipu cay ghep b d n g T K G 3 1 6 L .
Ldi cam o n : Bai bdo ndy dugc hodn thdnh bdi su hd trg kinh phi de ldi md so 0IC'03/03-20Ii-2 do Sd Khoa hgc vd cong ngh^ Hd Ngi cdp.
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