.. .」
Ap미ledChemlstl가l, VoI.13,N。．2,OCtober2009,159-192
나이팜 코어와 키토산 쉘 구조를 기본으로 한 열감응성 나노파티클의 합성과 특성
生희 남정표，최창용，장미경.나재운’
순천대학교 공과대학나노 ·고분자공학과 (E-mail;jwnah@sunchon.ac.kr’)
Synthesis and Characterization of Thermosensitive Nanoparticles Con」 ·ugated with Chitosan
끄쏘브뜨錘皿：Joung- Pyo Nam, Changyong Choi,Mi- Kyeong Jang,Jae- woon Nah Department ofPofymer ScienceandEngineering,SunchonNatinnalUniversity.
Jeonnam 540- 742, Korea (E- mail;jwnah@ sunchon.ac.kr’)
AbsrtaCt
New thermosensitivenanoparticles,based on PNIPAAm- AA core and chitosanshen structure, were designed and synthesized for the contro1led release of the loaded drug, PNIPAAm nanoparticle containing carboxylic group on their surface was
synthesized using emulsion polymerization.The particlesize of synthesized nanoparticleswas variedfrom 380 nm to 25 nm as temperatureof the dispersed medium increased. LMWSC- conjugated nanoparticles of Zwt% MBA, crosslinking monomer, leaded to a stable aqueous dispersionat concentrationof lmg/1ml otherwise showed gel co1lapsetemperature. The effectof temperature on the
dynamic behavior of the PNIPAAm chains were also studied by dynamic light scatteringand UV- Vis absorption measurements.
KeywordS: LMWSC, Lower criticalsolutiontemperature,Thermosensitive
1.IntroduCtion
A new chailenge is the development of the therm0sensitive nanogels with biologlcal activity,especiailyfor drug deliveryapPlications.Several authors have reportedthe thermosensitivegelsystems based on PNIPAAm conjugatedwith biomaterials.Kono et al. synthsized liposomes coated with a copolymers of NIPAAm and
N,N. didodecylacrylamide. 1 The release of calcein from the copolymer.modified
hposomes was very slow below LCST, whereas the releasewas rapldabove LCST.Katayama et al reported the thermosensitive PMPAAm nanogels conjugating with the
recePtor of protein kinase A.2
Recently our previous studies focused on chemical modifications,nanoparticle preparation,and drug- releasebehaviorsoflow m이ecularweightwater-s이ublechitosan
(LMWSC) .Inthe presentstudy,we have designednovelthermosensitivenanoparticles, based on PNIPAAm core exhibitingLCST behaviors and chitosan shell having biocompatibility,to develop the controlled release of the foaded drug. This study disclosed the synthesis, charaCterizationand thermosensitive behaviors of nanoparticles composed of either NIPAAm- co- AA or NIPAAm- co- AA conjugated with chitosan.
189
l90 정 현·남정표·최창용·장미경·나재운
2.Experimental 4砲槍n’ajs
Low molecularweightwater. solublechitosan(LMWSC) was obtainedfrom KITTOLIFE CO. Korea. LMWSC was modified to enhance water- solubihty as described previously
as a water. soluble chitosan (Mw: l0, 000, deacetylation degree= 97%).3 NIPAAm was
obtained from Fisher ScientificInc.(Fair Lawn, NJ, USA) and recrystallizedfrom hexane. MBA and AA were purchased from Aldrich(Milwaukee, Wl, USA) and used withoutfurtherpurification.Dialysistubing(MWCO= 12,000) was commerciaily obtained from SpeCtrum.
Preparation of jVIP/4Am - co- AA 끄anoparticjes
6.80 9 of MPAAm (6Ommol) ,0.5 9 ofSDS (1.7mmol) ,and 0.14 9 ofMBA (0.91mmol) were dissolvedin470 9 of doubledistilledwater,degassed with argon.The synthesis was carriedout under argon atmosphere to exclude oxygen. After heatingthe solution to 75 0C,O.s g of KPS (1.smmoI) and 3 g of AA (4.2mmol) in 3O g of water was added under rigorousstirring.The reactionbecame turbidand the reaCtionproceeded for 4 h at constant temperature. The obtained NIPAAm- co- AA nanoparticlesin aqueous soIutionwere dialyzedwith distinedwater by using a dialysismembrane
(cellusep⑧ ， molecular weight cut- off= 5, 000) for 24 h in order to purify the product.
．차엎thesjsof thern’〃seDsjtive〃柳oPartjcjesbased 卯 PA四가A爪 core 棚d chl'tos棚shejl
Z ml of NIPAAm ’AA solution (1.2 wt% ) was uniformly dispersed in ZOml of de- minerahzed water by ultrasonicfor ten minutes. The prepared NIPAAm- AA solutionwas slowlyadded intothe stirredLMWSC aqueous solution(10 mg in 10 ml de- mineralizedwater) and preadsorped for 2 hours at room temperature.After the preadsorb procedure, 0.5 mg of l- ethyl-3- (3’dimethyl;aminopropyl) carbodiimide (EDAC, Aldrich),the catalystof carboxyl. amine conjugation reaction,was added to the solution described above. The nanoparticle- LMWSC conjugation reaction was carried out for 4 hours with stirringat 25 oC.The resultingLMWSC- conjugatednanoparticle aqueous solution was dialyzed with distilledwater by using a dialysis
membrane (cellusep⑧ ， Mwco: 12, 000) for 24 h in order to purify the Product.
G盼aracterjzatjonoj’the ther끄7as印驪t,’ve 끄棚opart／팝쟎es
Thetemperature dependent particlesizeof NPAAm- AA and LMWSC conjugate nanoparticleswere measured by the dynamic lightscattering(DLS, Malvern,Zetasizer, 30OOHS) .The particlesize was measured in0.1 wt % of nanoparticlesdispersedin doubled distined water. At each temperature concerned, the solution was stand for s minutes to eqtulibrium. The gel- collapse temperature of nanoparticle solution,which is analoguetothe LCST of the lineartemperature,was determined by using a UV/ visible speCtrophotometer(PharmaciaBiotech,UltrospecI000E) .
3. Result and disccusion
응용화학．제l3권제2 호，2009
臘
나이팡코어와키토산쉘구조를기본으로한열감웅성나노파티클의합성과특성 19l
P玘 ararion01'＾『요4AD7-co-Bcrh·cBcjd끄ㄻoparticjes
The MPAAm- co. AA particleswere synthesizedby emulsionpolymerizationof
Table 1. higredients and Conversions for the synthesis of NIPAAm- AA particles
…
water (g) 500 500그으뜨 그으뜨
MPAAm(g) 6. 80(95o/ o) 6. 85(9lo/ o) 6. 75(870es쓰 －흐쯔쁘쑈L AA (g) 0. 3 (40, 0) 0. 3 (40/ 0) 0. 623es (ess쓰L－ 그쁘쁘츠些 MBA(g) 0. 14 (20/ 0) 0. 4l(5o, o) 0. 4l (5o／ 딥）」 쁘巨쑈工 ’
sDs(g) 5 05 ＿」 스 -－뜨느－ -
KPs(g) 0. 5 0. 5 es뜨… ee그스느．
Conversion 00/0 98.1 97.8 그프트 스뜨느－
’0O
-
- ㅓ - .
콘궁누”님져볍！=’'－체＊l
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’·． ＊숄쬔
’■넌＾,12｀峯
300 =O0
융8텨야
■0 20 30 ’D 50 60
T.m꾸戚毓1" 7. ’뻐r왯샅楸’썹느
Figure 2.Shrinkage behavl’orsofNIPAAm- AA partiClesas afljnctionoftemperature
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Figure3.EtfectotAA Contentonthegel- cOllapse temper〔I紬reofNIPAAm- AA nan0Partides indoubles dist·llled청，ater
Figure 1. Scanning electronmicrograph of PNIAA- 4 (5)nanoparticles
NIPAAm monomer in the presence of MBA as a cross- hnker, KPS, as an initiatorand SDS as a surfactant.The samPle number and detail ingredient of the NIPAAm- AA nanoparticles were shown in Table 1. From Table l, high conversion (>95% ) of all
nanoparticles were measured. The scanning 이ectronmicrograph of PNIAA ’4 nanoparticle
肌鰻跏鹹ㅉ枇7汰넙 《딴〃 御蔘挻 （》 is shown in Figure l. The electron
micrograph shows the synthesized nanoparticlesare spheres.
ParticjeSjze棚dthe Gej- coZlapseTemperatllreofj，硏PAAD7-AA particjes
The NIPAAm, AA nanopartlesexhibitsdifferentthermosensitivebehaviorswithparticle concentration in water. Figure 2 summarized the results of NIPAAm- AA particles obtained from dynamic lightscattering at various temperatures. Our results did not show significantdifferencewithintherange of4% . 12% acidcontents.The particlesize ofNIPAAm- AA particleisalm0stc0mp0sitionindependent.
Figure 2 also showed the significantdecrease of particlesize as the temperature increased from 10 OC to 50 。C. Results of transmittance measurement of NIPAAm- AA
AppliedChemi’stry,Vof.13,No.2,2009
192 정 현 남정표 최창용 장미경 나재운
particlesathigherconcentration(15 mg of particles/ lml 0 fwater) as a funCtionof temperatureare shown inFigure3. InFigure3,allofthe NIPAAm- AA particlesshow similatrendoftransmittance;that15,the transmittanceofthe particlewithdifferentAA contentdropped abruPtlyaround 32 OC,which 15in consistencewith the particlesize
meaSUrement.
TherD7osensjtjvebe力av7orsof끄ㄻoParticlesbased 棚 RW므4A爪core ㄻd ch／룔跡sanshell
StIZICt〃re.
As the NIPAAm- AA nanoparticlesslowlyadd a highly diluted
’매
LMWSC minteraction, Carried OUt SeemS that
ight be adsorbed at the surface conjugation reaction of
ed into
Of the nanoparticles
LMWSC Solution, carboxyl- amlne and
by the
the NIPAAm- AA particle with LMWSC was
Uslng 3’(3- dimethyl;aminopropyl) carbodiimlde NIPAAm- AA
(EDAC) . Therefore. it resultingnanoparticles
struCtures. Figure 4
may have chitosan shell
nanop LCST
articles.The particlessize was
Shows decreased
the at
SIZe bel0w
data LCST.
core and crosslinked of PNIAA- LMWSC
and re- decreased at the of
Increased at around light transmission
of■ls
experlment Figure s, it
chitosan conjugated
above LCST. The results
nanoparticles were shown in Figure 5. From the clearly shown thatthe cloud point conjugated PNIPAAm- AA nanoparticles solutionwas elevated about Z- 3 OC
of chitosan
compared with pure particles.
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아여야여여出，__ -
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-. - ’.】스구·위』L시驢」칡
’.*
一틉一건비
－ 를－’· l^＾·추급卜L매뷔구O*1
-O- ’.1‘쟈■JS婢L뱁 V뱅O(
-■． ’·I속，’··5’-L” 훵탤DC -·－’■■윅흘■螺 ．뜨｀·｀시1신氓
T. ’, .，삵．" （℃〕
Figure 4.The 『mosensitl’vebehaviors ot PNIAA . LMWSC nanopartiCleS.
T.．낱－t." （졉）
Figure 5.UV trEInsmittㄹIrlceotPNIPAAm- AA nanopartides conjug貶It놀19with ch枕osarlat various temDerㅌItures.
4. Conclusions
We have reportedthe firstexamPle ofthermosensitivenanoparticlesofPNIPAAm- AA core and chitosanshellStructurefor the controlledreleaseof the loaded drug.The thermosensitivecharacteristicsof chitosanconjugatednanoparticlesmake itpotentially usefulinthe designof a new type of intelligentdrug capsulesthat15compatiblewith cellsto release itspharmacological activity.
References
1. K. Kono, A. Henmi, H. Yamashita, H. Hayashi, T. Takaglshi, JConrrojledRejease, 59, 63 (1999) .
2.Y.Katayama, T. Sonoda, M. Maeda, 갸巍cro爪蹴ecules,34,8569 (2001), 3.J.W. Nah, M.K. Jang,J 』001m Sc" PartA.’P 耿爪 Chen7,40, 3796 (2002)
응용화학，제l3권제2호，2009
