ma e ials
A icle
Deposi ion o Ul a hin Nano-Hyd oxyapa i e Films
on Lase Mic o-Tex u ed Ti anium Su aces o P epa e
a Mul iscale Su ace Topog aphy o Imp o ed
Su ace We abili y/Ene gy
Ma ia Su mene a 1, Polina Niki yuk 1, Michael Hans 2and Roman Su mene 1,*
1Depa men o Expe imen al Physics, Na ional Resea ch Tomsk Poly echnic Uni e si y, Lenin A enue 30,
Tomsk 634029, Russia; [email p o ec ed] (M.S.); [email p o ec ed] (P.N.)
2Func ional Ma e ials, Ma e ials Science Depa men , Saa land Uni e si y, Saa b ücken 66123, Ge many;
[email p o ec ed]
*Co espondence: [email p o ec ed] o [email p o ec ed]; Tel.: +7-903-953-09-69
Academic Edi o : Ma k T. Whi ake
Recei ed: 22 July 2016; Accep ed: 14 Oc obe 2016; Published: 25 Oc obe 2016
Abs ac :
The p ima y aim o his s udy was o analyse he co ela ion be ween opog aphical
ea u es and chemical composi ion wi h he changes in we abili y and he su ace ee ene gy o
mic os uc u ed i anium (Ti) su aces. Pe iodic mic oscale s uc u es on he su ace o Ti subs a es
we e ab ica ed ia di ec lase in e e ence pa e ning (DLIP). Radio- equency magne on spu e
deposi ion o ul a hin nanos uc u ed hyd oxyapa i e (HA) ilms was used o o m an addi ional
nanoscale g ain mo phology on he mic oscale-s uc u ed Ti su aces o gene a e mul iscale su ace
s uc u es. The su ace cha ac e is ics we e e alua ed using a omic o ce mic oscopy and con ac
angle and su ace ee ene gy measu emen s. The s uc u e and phase composi ion o he HA ilms
we e in es iga ed using X- ay di ac ion. The HA-coa ed pe iodic mic oscale s uc u ed Ti subs a es
exhibi ed a signi ican ly lowe wa e con ac angle and a la ge su ace ee ene gy compa ed wi h
he uncoa ed Ti subs a es. Con ol o e he we abili y and su ace ee ene gy was achie ed using
Ti subs a es s uc u ed ia he DLIP echnique ollowed by he deposi ion o a nanos uc u ed HA
coa ing, which esul ed in he changes in su ace chemis y and he o ma ion o mul iscale su ace
opog aphy on he nano- and mic oscale.
Keywo ds:
biocompa ible coa ing; hyd oxyapa i e; mul iscale opog aphy; magne on spu e ing;
su ace pa e ning
1. In oduc ion
Cu en ly, a la ge numbe o de ices and implan s a e used in medicine [
1
]. Bioma e ials in he
o m o implan s (e.g., ligamen s, ascula g a s, hea al es, in aocula lenses, and den al implan s)
and medical de ices (e.g., pacemake s, biosenso s, and a i icial hea s) a e ex ensi ely used o eplace
and/o es o e he unc ion o dis u bed o de e io a ed issues o o gans, and hus imp o e he quali y
o li e and longe i y o human beings [
2
,
3
]. The ield o bioma e ials has shown apid g ow h in
keeping up wi h he demands o an aging popula ion [2,3].
Implan s should no only be mechanically esis an , bu should also be able o apidly heal he hos
o ganism. When implan ed in o li ing issue, all ma e ials ini ia e a hos esponse, and his ep esen s
he i s s eps o issue epai [
4
,
5
]. Mode n implan design is di ec ed owa ds making use o his
immune esponse o imp o e implan in eg a ion while p e en ing he pe pe ua ion o he immune
esponse, which leads o ch onic in lamma ion, o eign body eac ions, and hus loss o he in ended
unc ion [
4
,
5
]. In addi ion o de e mining some o he de o ma ion and s eng h cha ac e is ics o
Ma e ials 2016,9, 862; doi:10.3390/ma9110862 www.mdpi.com/jou nal/ma e ials
Ma e ials 2016,9, 862 2 o 15
implan s (such as he du abili y, elas ici y, and shape s abili y), i is necessa y o minimize he auma
caused by hei use and o iew he implan a ion wi h espec o healing a wound in o de o achie e a
as and ull pos ope a i e ehabili a ion o pa ien s [
5
]. As a esul , i is necessa y o ul il equen ly
inconsis en equi emen s wi h espec o he physical and mechanical p ope ies o he ma e ials
used o manu ac u e he speci ied p oduc s [
5
]. The physicochemical p ope ies o implan s s ongly
depend on he me hod used o o m he su ace o he implan s. Nume ous echniques ha e been
used o enhance he su ace compa ibili y o issue implan s. Mos o hese me hods in ol e mul iple
p epa a ion p ocedu es ha inco po a e coa ing and/o pa e ning s eps. Di ec lase in e e ence
pa e ning (DLIP) equi es a single p ocessing s ep and can be applied o a wide ange o ma e ials.
The p inciple behind his me hod is based on he unique in ensi y pa e n gene a ed by in e e ing
lase beams, which show pe iodici ies in he (sub-)mic on ange [6–8].
The compa ibili y o he medical implan su ace wi h biological issues is achie ed h ough he
use o a biocompa ible coa ing, which can be a laye o calcium phospha e (CaP). Biologically- ele an
CaP belongs o he o hophospha e g oup, and na u ally occu s in se e al biological s uc u es,
including ee h and bone [
9
]. Bone consis s o an ino ganic componen o biological apa i e as well
as an o ganic componen , which p ima ily consis s o collagen and wa e . Cu en ly, hyd oxyapa i e
(HA), Ca
10
(PO
4
)
6
(OH)
2
, is an op imum ma e ial o clinical p ac ice, wi h a simila s uc u e o
ha o he mine al componen o bone issue [
9
]. The basic echnological me hods ha a e used o
p epa e biocompa ible coa ings include plasma sp aying, ion-beam deposi ion, adio- equency ( )
magne on spu e ing, and elec ochemical deposi ion. R magne on spu e ing is a p ospec i e
echnique o he ab ica ion o implan coa ings, because i can be used o o m HA ilms ha ha e
low oughness and exhibi good adhesion o Ti subs a e [
10
,
11
]. The plasma pa ame e s o he
magne on spu e ing p ocess a ec he physicochemical and mechanical p ope ies o he CaP
ilms [
12
]. The deposi ion pa ame e s can be adjus ed o p oduce single-phase HA ilms gene a ed a a
high deposi ion a e and high he mal s abili y. Mo eo e , he chemical composi ion o he p ecu so
ma e ial used o deposi he HA coa ing is p ese ed [
13
]. The biocompa ibili y o HA has been
ho oughly in es iga ed and es ablished, and i has been shown o p omo e he p oli e a ion and
di e en ia ion o mesenchymal s em cells and adhesion o human ke a inocy e cell lines. In addi ion,
he imp o ed adhesion, p oli e a ion, and di e en ia ion, he inc eased alkaline phospha ase ac i i y
o p ima y human os eoblas cells, and he no mal cell g ow h o human emb yonic kidney cell lines
in he p esence o HA ha e been shown expe imen ally [14].
The li ing issue and he a i icial implan in e ac a he molecula le el, and he size o he
biological s uc u es anges om a ew nanome es o ens o mic ome es. The scien i ic expe ience
gained o da e has demons a ed ha he success ul in e ac ion be ween he bio issue and he
su ace o he implan equen ly depends on physico-chemical ma e ial p ope ies, such as he
chemical composi ion, mic os uc u e, oughness, we ing angle, and ee su ace ene gy (FSE) [
15
].
Thus, he aim o his s udy was o achie e he su ace s uc u ing o Ti using he DLIP echnique
ollowed by HA coa ing deposi ion h ough magne on spu e ing wi h pu e HA. Analyses o he
co ela ion be ween a ia ions in he opog aphical mul iscale Ti su ace ea u e, including Ti coa ed
wi h HA, and changes in he su ace we abili y and ene gy a e epo ed.
2. Ma e ials and Me hods
2.1. Sample P epa a ion
Technically pu e Ti was used as a subs a e. A high-powe ed pulsed Nd:YAG lase (Quan a-Ray
PRO210, Spec a Physics, San a Cla a, CA, USA) was used o lase in e e ence pa e ning.
The epe i ion a e and pulse du a ion o he lase we e 10 Hz and 10 ns, espec i ely. The undamen al
wa eleng h o he Nd:YAG lase sys em was 1064 nm, and sho e wa eleng hs we e ob ained h ough
second-ha monic gene a ion. Samples wi h a su ace a ea o 20
×
20
mm2
we e i adia ed a 355 nm
wi h mul iple adjacen 1
×
1–2
×
2 mm
2
spo s a a luency o 3.05
±
0.15 J
·
cm
2
. Line-like s uc u es
Ma e ials 2016,9, 862 3 o 15
wi h pe iodici ies o app oxima ely 4.5
µ
m and 8.4
µ
m we e ob ained using a wo-beam lase se up.
Fo c oss-like s uc u e ypes wi h he same pe iodici y, samples we e s uc u ed once, o a ed 90
◦
,
and hen s uc u ed a second ime.
2.2. Coa ing Deposi ion
A comme cially a ailable appa a us wi h a magne on sou ce (13.56 MHz) was used o deposi
he nanos uc u ed HA coa ing [
12
,
13
]. The HA coa ing was deposi ed a an ope a ing p essu e
o 0.4 Pa ( he acuum chambe was e acua ed o 10
−4
Pa) a a a ge –subs a e dis ance o 40 mm,
wi h a gon as he wo king gas, and wi h an gene a o powe o 500 W. The HA coa ing was deposi ed
o 8 h on o a subs a e moun ed on a g ounded subs a e holde , which esul ed in a coa ing hickness
o 650
±
50 nm. A a ge o pu e HA—syn hesized by he mechanochemical me hod—was p epa ed
acco ding o he p e iously desc ibed p ocedu es [
16
,
17
]. The a ge o magne on spu e ing
(220 mm diame e , 10 mm hick) was p epa ed ia ce amic echnology—i.e., he powde was p essed
a a p essu e o 70 MPa and hen annealed a 1100 ◦C o 1 h in ai .
2.3. A omic Fo ce Mic oscopy (AFM) Measu emen s
The quan i a i e analysis o he su ace mo phology o he uncoa ed and HA-coa ed subs a es
was pe o med wi h a Sol e P47-PRO (NT-MDT, Moscow, Russia) a omic o ce mic oscope (AFM)
using iangula golden silicon p obes (NT-NDT) wi h a ypical sp ing cons an o 28 N
·m−1
and a
esonance equency o 420 kHz. All o he images we e collec ed in con ac AFM mode in ai a a
ypical equency o 1.5 Hz wi h an image esolu ion o 256 poin s pe line. Squa es o di e en sizes
(5
×
5
µm2
and 35
×
35
µm2
) we e scanned, and he No a SPM so wa e (NT-MDT, Moscow, Russia)
was used o analyse he su ace oughness. Th ee di e en 3D pa ame e s we e used o cha ac e ize he
su ace oughness: (S
a
), which is he a i hme ic mean o he absolu e alues o he su ace depa u e
om he mean plane in he samples a ea; he oo mean squa e oughness (S
q
), which is an index used
o ep esen he s anda d de ia ion o he su ace heigh s; and S
d
, which is he de eloped in e acial
a ea a io.
2.4. X- ay Di ac ion (XRD)
An X- ay di ac ome e (Shimadzu XRD-6000, Tokyo, Japan) was used o iden i y he c ys alline
s uc u e o he HA-coa ed Ti ha we e p e iously ea ed o p epa e pa allel and c ossed g oo es
wi h di e en pe iodici ies. The ypical i adia ion condi ions we e 40 kV and 30 mA using Cu-K
α
adia ion (1.5405 Å); he 2
θ
scan anged om 10
◦
o 60
◦
wi h a s ep size o 0.02
◦
a a speed o
2 deg/min
and a g azing angle o 3
◦
. The a e age c ys alli e size was de e mined using Sche e ’s
equa ion om he b oadening o he di ac ion peaks; his de e mina ion was pe o med wi h he
Powde Cell 2.4 so wa e (FIMRT, Be lin, Ge many), and he ins umen al b oadening was conside ed.
An ins umen al b oadening o 0.1
◦
in 2
θ
was de e mined by he ull wid h a hal maximum (FWHM)
o a silicon powde .
2.5. Con ac Angle and Su ace F ee Ene gy Measu emen s
Con ac angle analyses we e pe o med using an op ical con ac angle appa a us (OCA15 Plus
Da a Physics Ins umen s GmbH, Filde s ad , Ge many) along wi h he SCA20 so wa e (Da a Physics
Ins umen s GmbH, Filde s ad , Ge many). The con ac angle (CA) o wa e in ai was measu ed
using a sessile d op me hod. A minimum o 10 d ople s (2
µ
L, 5
µ
L
·s−1
) o wa e and h ee d ople s
o diiodome hane o e hylene glycol we e seeded on he su ace o each sample. The su ace ee
ene gy was calcula ed using he Owens–Wend –Rabel–Kaelble (ORWK) me hod. Th ee di e en media
(wa e , diiodome hane, and e hylene glycol) we e used o he calcula ions, and all he measu emen s
we e pe o med acco ding o he s udy [
18
]. The phenomenon o con ac angle hys e esis was also
obse ed in he op ical con ac angle appa a us using a sessile liquid (wa e ) d ople . A e he liquid
has ad anced o e a p e iously unwe ed su ace (i.e., when he solid/liquid con ac a ea inc eases),
Ma e ials 2016,9, 862 4 o 15
he maximum con ac angle a he h ee-phase con ac line is e e ed o as he ad ancing angle
(
θa
). A minimum con ac angle is measu ed a he con ac line when he liquid is e ac ed o e a
p e iously we ed su ace (i.e., when he con ac a ea sh inks); his is e e ed o as a eceding angle
(
θ
). Con ac angle hys e esis is de ined as he di e ence be ween he (maximum) ad ancing and
(minimum) eceding angles: ∆θhys =θa−θ [19].
3. Resul s and Discussion
3.1. Su ace Roughness and Mo phology
To s udy he changes in he mo phology, AFM analysis was ca ied ou on he uncoa ed and
HA-coa ed pa e ned Ti subs a es. The esul s p esen ed in Figu e 1 e eal ha deposi ion o
he HA coa ing esul ed in changes in mic oscale su ace oughness o he ini ial s uc u ed Ti
subs a e. In gene al, a e HA coa ing deposi ion, he oughness pa ame e s S
a
and S
q
dec eased.
Fo he g oo es wi h a pe iodici y o 8.4
µm
, he a e age su ace oughness a e deposi ion o he HA
coa ing was lowe han ha o he s uc u ed Ti subs a e. This phenomenon may be ela ed o he
g ow h mechanism o he HA coa ing. Du ing he g ow h, he HA coa ing ends o ill he g oo es,
which esul s in a su ace smoo hening e ec .
Ma e ials 2016, 9, 862 4 o 16
is e ac ed o e a p e iously we ed su ace (i.e., when he con ac a ea sh inks); his is e e ed o
as a eceding angle (θ). Con ac angle hys e esis is de ined as he di e ence be ween he (maximum)
ad ancing and (minimum) eceding angles: Δθ =θ
−θ [19].
3. Resul s and Discussion
3.1. Su ace Roughness and Mo phology
To s udy he changes in he mo phology, AFM analysis was ca ied ou on he uncoa ed and
HA-coa ed pa e ned Ti subs a es. The esul s p esen ed in Figu e 1 e eal ha deposi ion o he HA
coa ing esul ed in changes in mic oscale su ace oughness o he ini ial s uc u ed Ti subs a e. In
gene al, a e HA coa ing deposi ion, he oughness pa ame e s Sa and Sq dec eased. Fo he g oo es
wi h a pe iodici y o 8.4 μm, he a e age su ace oughness a e deposi ion o he HA coa ing was
lowe han ha o he s uc u ed Ti subs a e. This phenomenon may be ela ed o he g ow h
mechanism o he HA coa ing. Du ing he g ow h, he HA coa ing ends o ill he g oo es, which
esul s in a su ace smoo hening e ec .
(a) (b)
Figu e 1. The oughness pa ame e s o di e en Ti su ace pa e ns wi h a 35 × 35 μm scan a ea:
■—wi hou hyd oxyapa i e (HA) ilm, and ○—wi h HA ilm. (a) Sa oughness pa ame e ; (b) Sq
oughness pa ame e
Figu es 2–5 show ypical AFM images o he HA coa ing p epa ed using magne on spu e ing
on he lase mic o- ex u ed Ti su aces. The mic os uc u e o he su aces is easily obse ed using
35 × 35 μmscan a eas. Fo he 5 × 5 µm2 scan a ea, clea g ains o he HA coa ing wi h de ini e
bounda ies can be obse ed (Figu es 2d and 3d). The deposi ed coa ing was homogenous and
e ealed a egula g ain-like mo phology, which is ypical o a hin ilm deposi ed by magne on
spu e ing [20,21]. The su ace had a g ain-like mo phology wi h a g ain size om 0.36 o 0.73 µm in
he 5 × 5 μm scan a ea (Figu es 2d and 3d). The e o e, he su ace o he ea ed Ti subs a es
exhibi ed a mul iscale s uc u e.
The su ace opog aphy on he mic oscale, sub-mic oscale, and nanoscale changed a e he HA
coa ing deposi ion, and his was obse ed in he AFM p o ile. Scans ob ained o he 35 × 35 µm2 scan
a ea showed ha changes in he su ace opog aphy occu ed a e he HA coa ing deposi ion.
Du ing deposi ion, he ilm p esumably ills he g oo es o he Ti subs a e. The AFM p o ile analysis
o he HA-coa ed Ti shows a su ace deco a ed wi h nanoscale g ains (Figu es 2d and 3d). The
a e age g ain heigh was app oxima ely 30 nm, which esul ed in an inc ease in he nanoscale
oughness o he su ace. The mos signi ican changes o he su ace opog aphy occu ed in su ace
s uc u ed Ti wi h pa allel g oo es. Fo a 5 × 5 µm2 scan a ea, he HA coa ing esul ed in signi ican
sh inkage in he as-p epa ed g oo es, and he s uc u e o he g oo es was modi ied (Figu e 2b,d).
As shown in Figu e 2b, sepa a e g oo es wi h pa allel pe iodici y can be cha ac e ized wi h a ull
wid h a hal -maximum (FWHM) o ~2.2 µm and an a e age g oo e dep h o ~500 nm. A e he HA
Figu e 1.
The oughness pa ame e s o di e en Ti su ace pa e ns wi h a 35
×
35
µm2
scan
a ea:

—wi hou hyd oxyapa i e (HA) ilm, and
#
—wi h HA ilm. (
a
)S
a
oughness pa ame e ;
(b)Sq oughness pa ame e .
Figu es 2–5show ypical AFM images o he HA coa ing p epa ed using magne on spu e ing
on he lase mic o- ex u ed Ti su aces. The mic os uc u e o he su aces is easily obse ed
using 35
×
35
µm2
scan a eas. Fo he 5
×
5
µ
m
2
scan a ea, clea g ains o he HA coa ing wi h
de ini e bounda ies can be obse ed (Figu es 2d and 3d). The deposi ed coa ing was homogenous and
e ealed a egula g ain-like mo phology, which is ypical o a hin ilm deposi ed by magne on
spu e ing [
20
,
21
]. The su ace had a g ain-like mo phology wi h a g ain size om 0.36 o 0.73
µ
m
in he 5
×
5
µm2
scan a ea (Figu es 2d and 3d). The e o e, he su ace o he ea ed Ti subs a es
exhibi ed a mul iscale s uc u e.
The su ace opog aphy on he mic oscale, sub-mic oscale, and nanoscale changed a e he HA
coa ing deposi ion, and his was obse ed in he AFM p o ile. Scans ob ained o he 35
×
35
µ
m
2
scan a ea showed ha changes in he su ace opog aphy occu ed a e he HA coa ing deposi ion.
Du ing deposi ion, he ilm p esumably ills he g oo es o he Ti subs a e. The AFM p o ile analysis
o he HA-coa ed Ti shows a su ace deco a ed wi h nanoscale g ains (Figu es 2d and 3d). The a e age
g ain heigh was app oxima ely 30 nm, which esul ed in an inc ease in he nanoscale oughness o
he su ace. The mos signi ican changes o he su ace opog aphy occu ed in su ace s uc u ed
Ma e ials 2016,9, 862 5 o 15
Ti wi h pa allel g oo es. Fo a 5
×
5
µ
m
2
scan a ea, he HA coa ing esul ed in signi ican sh inkage
in he as-p epa ed g oo es, and he s uc u e o he g oo es was modi ied (Figu e 2b,d). As shown
in Figu e 2b, sepa a e g oo es wi h pa allel pe iodici y can be cha ac e ized wi h a ull wid h a
hal -maximum (FWHM) o ~2.2
µ
m and an a e age g oo e dep h o ~500 nm. A e he HA coa ing
deposi ion, he FWHM dec eased o ~1.8
µ
m and he a e age g oo e dep h educed o ~200 nm
(Figu e 2d).
Ma e ials 2016, 9, 862 5 o 16
coa ing deposi ion, he FWHM dec eased o ~1.8 µm and he a e age g oo e dep h educed o ~200
nm (Figu e 2d).
Figu e 2. A omic o ce mic oscopy (AFM) images o he su ace opog aphies o Ti samples wi h
pa allel g oo es and a pe iodici y o app oxima ely 4.5 µm. (a) 35 × 35 μm

; (b) 5 × 5 μm

wi hou a
HA ilm; (c) 35 × 35 μm

; and (d) 5 × 5 μm

wi h a HA ilm.
Figu e 2.
A omic o ce mic oscopy (AFM) images o he su ace opog aphies o Ti samples wi h
pa allel g oo es and a pe iodici y o app oxima ely 4.5
µ
m. (
a
) 35
×
35
µm2
; (
b
) 5
×
5
µm2
wi hou a
HA ilm; (c) 35 ×35 µm2; and (d) 5 ×5µm2wi h a HA ilm.

Ma e ials 2016,9, 862 6 o 15
Ma e ials 2016, 9, 862 6 o 16
Figu e 3. AFM images o he opog aphies o Ti samples wi h a c ossed pe iodici y o app oxima ely
4.5 µm. (a) 35 × 35 μm

; (b) 5 × 5 μm

wi hou a HA ilm; (c) 35 × 35 μm

; and
(d) 5 × 5 μm

wi h a HA ilm.
Figu e 3.
AFM images o he opog aphies o Ti samples wi h a c ossed pe iodici y o app oxima ely
4.5
µ
m. (
a
) 35
×
35
µm2
; (
b
) 5
×
5
µm2
wi hou a HA ilm; (
c
) 35
×
35
µm2
; and (
d
) 5
×
5
µm2
wi h a
HA ilm.
Ma e ials 2016,9, 862 7 o 15
Ma e ials 2016, 9, 862 7 o 16
Changes in he su ace opog aphy can be obse ed o he c ossed pa e ns on he Ti su ace.
Mo eo e , a e deposi ion o he HA coa ing, he c oss-pa e n opog aphy could no longe be clea ly
obse ed, as he g oo es we e illed wi h he coa ing ma e ial. Fo he Ti samples wi h pa allel g oo es
wi h a pe iodici y o 8.4 µm, a lowe amoun o he coa ing ma e ial illed he g oo es (Figu e 4a,b).
Fo he Ti samples wi h c ossed g oo es wi h a pe iodici y o app oxima ely 8.4 µm, he changes
in he su ace opog aphy we e mo e p onounced han in he g oo es wi h a pe iodici y o
app oxima ely 4.5 µm (Figu e 5a,b). The c ossed pa e ns on he Ti su ace we e s ill obse ed a e
he deposi ion p ocess.
Figu e 4. AFM images o he opog aphies o Ti samples wi h pa allel g oo es wi h a pe iodici y o
app oxima ely 8.4 µm. (a) 35 × 35 μm; (b) 35 × 35 μm wi h a HA ilm.
Figu e 5. AFM images o he opog aphies o Ti samples wi h c ossed g oo es wi h a pe iodici y o
app oxima ely 8.4 µm. (a) 35 × 35 μm; (b) 35 × 35 μm wi h a HA ilm.
Topog aphical ea u es on ma e ial su aces a e impo an o cell and issue esponse o
bioma e ials [22–24]. Mic o- ough su aces may s imula e g ea e bone con ac wi h he ma e ial by
p omo ing he p oduc ion o local os eogenic ac o s and he exp ession o di e en ia ion ma ke s.
Howe e , he ole o nanome e oughness has no been clea ly de ined [22–24].
P e iously published esul s showed ha he opog aphy o mic o- ough Ti su aces can
signi ican ly in luence he a achmen and g ow h o cells [22]. Mul idi ec ional g oo e designs ha e
been shown o con ibu e o imp o ed MC3T3-E1 cell adhesion in di e en di ec ions [24]. La ge
Figu e 4.
AFM images o he opog aphies o Ti samples wi h pa allel g oo es wi h a pe iodici y o
app oxima ely 8.4 µm. (a) 35 ×35 µm2; (b) 35 ×35 µm2wi h a HA ilm.
Ma e ials 2016, 9, 862 7 o 16
Changes in he su ace opog aphy can be obse ed o he c ossed pa e ns on he Ti su ace.
Mo eo e , a e deposi ion o he HA coa ing, he c oss-pa e n opog aphy could no longe be clea ly
obse ed, as he g oo es we e illed wi h he coa ing ma e ial. Fo he Ti samples wi h pa allel g oo es
wi h a pe iodici y o 8.4 µm, a lowe amoun o he coa ing ma e ial illed he g oo es (Figu e 4a,b).
Fo he Ti samples wi h c ossed g oo es wi h a pe iodici y o app oxima ely 8.4 µm, he changes
in he su ace opog aphy we e mo e p onounced han in he g oo es wi h a pe iodici y o
app oxima ely 4.5 µm (Figu e 5a,b). The c ossed pa e ns on he Ti su ace we e s ill obse ed a e
he deposi ion p ocess.
Figu e 4. AFM images o he opog aphies o Ti samples wi h pa allel g oo es wi h a pe iodici y o
app oxima ely 8.4 µm. (a) 35 × 35 μm; (b) 35 × 35 μm wi h a HA ilm.
Figu e 5. AFM images o he opog aphies o Ti samples wi h c ossed g oo es wi h a pe iodici y o
app oxima ely 8.4 µm. (a) 35 × 35 μm; (b) 35 × 35 μm wi h a HA ilm.
Topog aphical ea u es on ma e ial su aces a e impo an o cell and issue esponse o
bioma e ials [22–24]. Mic o- ough su aces may s imula e g ea e bone con ac wi h he ma e ial by
p omo ing he p oduc ion o local os eogenic ac o s and he exp ession o di e en ia ion ma ke s.
Howe e , he ole o nanome e oughness has no been clea ly de ined [22–24].
P e iously published esul s showed ha he opog aphy o mic o- ough Ti su aces can
signi ican ly in luence he a achmen and g ow h o cells [22]. Mul idi ec ional g oo e designs ha e
been shown o con ibu e o imp o ed MC3T3-E1 cell adhesion in di e en di ec ions [24]. La ge
Figu e 5.
AFM images o he opog aphies o Ti samples wi h c ossed g oo es wi h a pe iodici y o
app oxima ely 8.4 µm. (a) 35 ×35 µm2; (b) 35 ×35 µm2wi h a HA ilm.
Changes in he su ace opog aphy can be obse ed o he c ossed pa e ns on he Ti su ace.
Mo eo e , a e deposi ion o he HA coa ing, he c oss-pa e n opog aphy could no longe be clea ly
obse ed, as he g oo es we e illed wi h he coa ing ma e ial. Fo he Ti samples wi h pa allel g oo es
wi h a pe iodici y o 8.4 µm, a lowe amoun o he coa ing ma e ial illed he g oo es (Figu e 4a,b).
Fo he Ti samples wi h c ossed g oo es wi h a pe iodici y o app oxima ely 8.4
µ
m, he
changes in he su ace opog aphy we e mo e p onounced han in he g oo es wi h a pe iodici y o
app oxima ely 4.5
µ
m (Figu e 5a,b). The c ossed pa e ns on he Ti su ace we e s ill obse ed a e he
deposi ion p ocess.
Topog aphical ea u es on ma e ial su aces a e impo an o cell and issue esponse o
bioma e ials [
22
–
24
]. Mic o- ough su aces may s imula e g ea e bone con ac wi h he ma e ial
by p omo ing he p oduc ion o local os eogenic ac o s and he exp ession o di e en ia ion ma ke s.
Howe e , he ole o nanome e oughness has no been clea ly de ined [22–24].
Ma e ials 2016,9, 862 8 o 15
P e iously published esul s showed ha he opog aphy o mic o- ough Ti su aces can
signi ican ly in luence he a achmen and g ow h o cells [
22
]. Mul idi ec ional g oo e designs
ha e been shown o con ibu e o imp o ed MC3T3-E1 cell adhesion in di e en di ec ions [
24
].
La ge mic og oo es (g ea e han ~1 µm in dep h) ha e been p oposed o inc ease plaque up ake in
den al applica ions.
Ule ich e al. in es iga ed he e ec o mul iscale lase ex u ing o a Ti6Al4V subs a e on he
adhesion o os eoblas s [
25
]. The su ace chemical composi ion can in luence cell a achmen and
eac ion o a me al by modi ying he adso p ion o p o eins o by ac i a ing di e en cellula pa hways
o nea by cells [
25
]. Unique lase -induced s uc u es can modi y he mo phology and local chemis y
o he su ace, which makes i mo e a ou able o cells o g ow in ce ain pa e ns o o g ow a a
pa icula densi y, depending on he ea u es a a ious size scales [26].
3.2. Phase and S uc u e Cha ac e iza ion
The ypical XRD pa e ns o HA-coa ed pa e ned Ti subs a es wi h c ossed g oo es and
pe iodici ies o 4.5
µ
m and 8.4
µ
m a e p esen ed in Figu e 6. Only he e lexes a ibu ed o he HA
coa ing a e obse ed, which con i ms ha he HA ilm is c ys alline and phase-pu e. The p e e en ial
(002) c ys allog aphic o ien a ion is obse ed, which is ypical o an magne on spu e -deposi ed
hin ilm [
27
]. Mo eo e , he c ys allog aphic o ien a ions o he deposi ed HA coa ing can be con olled
o ei he (002) o (300) by modula ing he deposi ion pa ame e s, he hickness o he HA ilm,
and he mo emen o he subs a e du ing he deposi ion p ocess [
12
]. The c ys alli e size and
mic os ain de e mined o he HA coa ing we e 34
±
1 nm and 0.06%, espec i ely. In he pa e n,
only he peaks a ibu ed o he hexagonal
α
-Ti phase we e iden i ied. The la ice pa ame e s o he Ti
subs a e we e de e mined o be b=a= 2.9458 and c= 4.677 Å. The la ice pa ame e s o he HA coa ing
p epa ed on he Ti su ace we e de e mined as b=a= 9.4125 and c= 6.9167 Å. The c ys alli e size and
mic os ain e alua ed o he Ti subs a e we e 42
±
2 nm and 0.05%, espec i ely. No signi ican e ec
o he Ti su ace, which was pa e ned by he DLIP echnique, was obse ed on he phase composi ion
o ei he he Ti subs a es o he HA-coa ed s uc u ed Ti subs a es. Thus, acco ding o he XRD
esul s, no su ace TiO
x
(x < 2) laye was o med h ough su ace p ocessing by he DLIP echnique. I
has also been epo ed elsewhe e ha DLIP p ocessing o he Ti su ace does no esul in he o ma ion
o an oxide laye [
7
,
28
]. This is he p ima y di e ence be ween su ace p ocessing o Ti by DLIP and
con en ional hea ea men o Ti in d y ai , whe e Ti is oxidized [29].
Ma e ials 2016, 9, 862 8 o 16
mic og oo es (g ea e han ~1 µm in dep h) ha e been p oposed o inc ease plaque up ake in den al
applica ions.
Ule ich e al. in es iga ed he e ec o mul iscale lase ex u ing o a Ti6Al4V subs a e on he
adhesion o os eoblas s [25]. The su ace chemical composi ion can in luence cell a achmen and
eac ion o a me al by modi ying he adso p ion o p o eins o by ac i a ing di e en cellula
pa hways o nea by cells [25]. Unique lase -induced s uc u es can modi y he mo phology and local
chemis y o he su ace, which makes i mo e a ou able o cells o g ow in ce ain pa e ns o o
g ow a a pa icula densi y, depending on he ea u es a a ious size scales [26].
3.2. Phase and S uc u e Cha ac e iza ion
The ypical XRD pa e ns o HA-coa ed pa e ned Ti subs a es wi h c ossed g oo es and
pe iodici ies o 4.5 µm and 8.4 µm a e p esen ed in Figu e 6. Only he e lexes a ibu ed o he HA
coa ing a e obse ed, which con i ms ha he HA ilm is c ys alline and phase-pu e. The p e e en ial
(002) c ys allog aphic o ien a ion is obse ed, which is ypical o an magne on spu e -deposi ed
hin ilm [27]. Mo eo e , he c ys allog aphic o ien a ions o he deposi ed HA coa ing can be
con olled o ei he (002) o (300) by modula ing he deposi ion pa ame e s, he hickness o he HA
ilm, and he mo emen o he subs a e du ing he deposi ion p ocess [12]. The c ys alli e size and
mic os ain de e mined o he HA coa ing we e 34 ± 1 nm and 0.06%, espec i ely. In he pa e n,
only he peaks a ibu ed o he hexagonal α-Ti phase we e iden i ied. The la ice pa ame e s o he
Ti subs a e we e de e mined o be b = a = 2.9458 and c = 4.677 Å. The la ice pa ame e s o he HA
coa ing p epa ed on he Ti su ace we e de e mined as b = a = 9.4125 and c = 6.9167 Å. The c ys alli e
size and mic os ain e alua ed o he Ti subs a e we e 42 ± 2 nm and 0.05%, espec i ely. No
signi ican e ec o he Ti su ace, which was pa e ned by he DLIP echnique, was obse ed on he
phase composi ion o ei he he Ti subs a es o he HA-coa ed s uc u ed Ti subs a es. Thus,
acco ding o he XRD esul s, no su ace TiO
x
(x < 2) laye was o med h ough su ace p ocessing by
he DLIP echnique. I has also been epo ed elsewhe e ha DLIP p ocessing o he Ti su ace does
no esul in he o ma ion o an oxide laye [7,28]. This is he p ima y di e ence be ween su ace
p ocessing o Ti by DLIP and con en ional hea ea men o Ti in d y ai , whe e Ti is oxidized [29].
Figu e 6. A ypical X- ay di ac ion (XRD) pa e n o HA-coa ed s uc u ed Ti wi h c ossed g oo es
and a pe iodici y o 4.5 µm.
Figu e 6.
A ypical X- ay di ac ion (XRD) pa e n o HA-coa ed s uc u ed Ti wi h c ossed g oo es
and a pe iodici y o 4.5 µm.
Ma e ials 2016,9, 862 9 o 15
3.3. We abili y and Su ace F ee Ene gy
The e olu ion o he con ac angle and wa e hys e esis o d ople s on he lase - ea ed uncoa ed
(

) and HA-coa ed (
#
) Ti su aces is p esen ed in Figu e 7. The con ac angle o he c ossed g oo es
wi h a pe iodici y o app oxima ely 8.4
µ
m is la ge han ha o he pa allel g oo es wi h a pe iodici y
o app oxima ely 8.4 µm o bo h he HA-coa ed and uncoa ed subs a es.
Ma e ials 2016, 9, 862 9 o 16
3.3. We abili y and Su ace F ee Ene gy
The e olu ion o he con ac angle and wa e hys e esis o d ople s on he lase - ea ed uncoa ed
(■) and HA-coa ed (○) Ti su aces is p esen ed in Figu e 7. The con ac angle o he c ossed g oo es
wi h a pe iodici y o app oxima ely 8.4 µm is la ge han ha o he pa allel g oo es wi h a
pe iodici y o app oxima ely 8.4 µm o bo h he HA-coa ed and uncoa ed subs a es.
The uncoa ed Ti su ace wi h pa allel g oo es and a pe iodici y o app oxima ely 4.5 µm
esul ed in a high s a ic wa e CA o 99° ± 2°, which is indica i e o su ace hyd ophobici y. The
a e age wa e CA o he Ti subs a e a e he deposi ion o he HA ilm was measu ed as 75° ± 4°,
which is associa ed wi h su ace hyd ophilici y. In Figu e 6, he wa e CA hys e esis was de e mined
o be 96.4° ± 1.9° and 67.4° ± 3.4° o he uncoa ed and HA-coa ed Ti su aces, espec i ely.
The su ace we abili y o a i icial ma e ials is one o he mos impo an ac o s ha de e mines
cell adhesion. Tamada e al. claimed ha a su ace wi h a wa e con ac angle o 70° ep esen s he
mos sui able su ace o cell adhesion [30]. In ou s udy, he wa e con ac angle was close o 70° a e
he deposi ion o HA. The e o e, he coa ing can p o ide bene icial e ec s o cell adhesion compa ed
wi h uncoa ed Ti su aces. Su ace nano ex u es—which p o ide inc eased su ace a ea and ine su ace
oughness—may esul in imp o ed mechanical in e locking be ween he issue and implan [31].
5101520
70
75
80
85
90
95
100
105
Pa e ns
4,5 pa allel 4,5 c ossed 8,4 pa allel 8,4 c ossed
Con ac angle, î
(a)
5101520
55
60
65
70
75
80
85
90
95
100
105
Pa e ns
4,5 pa allel 4,5 c ossed 8,4 pa allel 8,4 c ossed
Wa e Hys e esis, î
(b)
Figu e 7. The con ac angle (a) and wa e hys e esis; (b) measu emen s o di e en pa e ns on he
su ace o Ti: ■—wi hou HA ilm, and ○—wi h HA ilm.
Figu e 7.
The con ac angle (
a
) and wa e hys e esis; (
b
) measu emen s o di e en pa e ns on he
su ace o Ti: —wi hou HA ilm, and #—wi h HA ilm.
The uncoa ed Ti su ace wi h pa allel g oo es and a pe iodici y o app oxima ely 4.5
µ
m
esul ed in a high s a ic wa e CA o 99
◦±
2
◦
, which is indica i e o su ace hyd ophobici y.
The a e age wa e CA o he Ti subs a e a e he deposi ion o he HA ilm was measu ed as
75
◦±
4
◦
, which is associa ed wi h su ace hyd ophilici y. In Figu e 6, he wa e CA hys e esis was
de e mined o be 96.4
◦±
1.9
◦
and 67.4
◦±
3.4
◦
o he uncoa ed and HA-coa ed Ti su aces, espec i ely.
The su ace we abili y o a i icial ma e ials is one o he mos impo an ac o s ha de e mines
cell adhesion. Tamada e al. claimed ha a su ace wi h a wa e con ac angle o 70
◦
ep esen s he mos
sui able su ace o cell adhesion [
30
]. In ou s udy, he wa e con ac angle was close o 70
◦
a e he
deposi ion o HA. The e o e, he coa ing can p o ide bene icial e ec s o cell adhesion compa ed wi h
uncoa ed Ti su aces. Su ace nano ex u es—which p o ide inc eased su ace a ea and ine su ace
oughness—may esul in imp o ed mechanical in e locking be ween he issue and implan [31].
The su ace ee ene gy
σ
calcula ions using he CA da a indica ed ha HA-coa ed Ti su aces
wi h pa allel g oo es and a pe iodici y o app oxima ely 8.4
µ
m had a signi ican ly la ge su ace