Characteristic of hyaluronic acid derivative films cross-linked by polyethylene glycol of low water Characteristic of hyaluronic acid derivative films cross-linked by polyethylene glycol of low water

Characteristic of hyaluronic acid derivative films cross-linked by polyethylene glycol of low water

  • 期刊名字:中国人民解放军军医大学学报
  • 文件大小:445kb
  • 论文作者:Chen Jinghua,Chen Jingtao,Xu Z
  • 作者单位:College of Publishing and Printing,College of Materials Science and Technology,The Institute of Qisheng Biomaterial Tech
  • 更新时间:2020-12-22
  • 下载次数:
论文简介

Available online at www.sciencedirect.comJOURNAL OFMEDICAL中ScienceDirectCOLLEGES OF PLAJournal of Medical Colleges of PLA 23(2008)15 -19www. elsevier.com/locate/jmcplaCharacteristic of hyaluronic acid derivative films cross-linkedby polyethylene glycol of low water contentChen Jinghual2 , Chen Jingtao', Xu Zheng2, Gu Qisheng3'College of Publishing and Printing, University of Shanghai for Science and Technology, Shanghai 200093, China'College of Materials Science and Technology, Tongji University, Shanghai 200092, ChinaThe Institute of Qisheng Biomaterial Technology, Shanghai 201106, ChinaReceived 25 May 2006; accepted 18 October 2007Abstractof low water content. Methods: The cross-linked HA film with 200 μm thickness was got at atmospheric pressure at 25c for 5 d. After dried, cross-linked films of 10 mmx 10 mm were weighed and immersed in phosphate buffered saline(PBS pH 7.45)at 37C for 24 h. Then the solution fraction and water content were estimated. Meanwhile, cross-linkedHA derivative films were immersed in phosphate buffered saline (PBS: pH 7.45) at 37C for determined time and thenimplanted subcutaneously in the back of white rats to test in viro or in vivo degradation characteristic. Results andConclusion: HA hydrogel cros-linked by polyethylene glycol with water content is as low as 60% and this kind of HAderivative has a slow degradation rate.Keywords: hyaluronic acid; polyethylene glycol; water content; degradation rate1. Introductionapplication as a type of biomedical materials[1].Therefore, chemical modifications are required onHyaluronic acid (HA) is a kind of glycosam-natural HA to improve its water-soluble ancinoglycuronans, which has a high molecular weighbiodegradation characteristics when it is applied tolinear polysaccharide with the repeating di-medicine in the non-soluble form, for example, as asaccharide structure composed of β-D-glucuronicmatrix in drug delivery systems and a sheet toacid and 2-acetamido-2-deoxy-B-D-glucose resi-prevent tissue adhesion. When HA is cross-linkeddues connected by β (1→3) and β (1- +4) links.by divinylsulphone, epichlorhydrin and phosphorylUnmodified HA has high capacity for lubrication,chloride, we may obtain HA derivative with lowwater sorption and water retention, which makes itdensities, that is, very high water contents such asused for a variety of clinical applications such as95% in weight, which made HA derivatives veryviscosupplementation for arthritis, wound healing,low in mechanical strength and readily bio-ocular surgery and plastic surgery. But natural HAdegradable. Even if HA hydrogel modified byis easily .soluble in water and is not resistant towater-soluble carbodiimides has much lower waterenzymatic degradation, thus hindering its widercontents than 90%, its biodegradation rates are veryhigh [21.*. Corresponding author.中国煤化工e modified byE-mail:cjhshl@ 163.com (Chen J.)polye; analyzed for itswater:fYHC N M H Groperties. Based16Chen. Jinghua et al.SJournal of Medical Colleges ofPLA 232008)15-19on all the above analysis, we may totally obtain HA2.4. Implantation in ratsderivative hydrogel with water content as low_ as60% in weight and its more important thing is thatCross-linked HA derivative flms with knownthis kind of HA derivative has a slow degradationdry weights were sterilized with ethylene oxide gasrate.prior to implantation, washed with sterilized PBS(pH 7.45) and implanted subcutaneously in the2. Materials and methodsback of white rats. After determined intervals oftime, the rats were killed to explant the samples,2.1. Materials and cross-linking procedurewhich were then weighed after drying. The extentAll the materials used to obtain HA derivativeof in vivo degradation was expressed as a per-cross-linked by polyethylene glycol (PEG) may becentage of the weight of films remaining afterknown in the previous study [3], and the process ofimplantation.the resulting solution of HA derivative modified byPEG was shown in Reference [3]. After that, the3. Resultsresulting resolution was cast into a Petri dish andallowed to dry under atmospheric pressure at 25C3.1. Cross-linked of HA derivative filmfor 5 d to yield cross-linked HA derivative films of200 μm thickness. Then it was removed from theFig. 1 shows the water content of HA deriva-Petri dish and washed with distilled water severaltive films obtained by casting HA derivative solu-times, the films were further dried under vacuumtions of pH4.7, 6.0 and 8.0 containing differentand weighed.concentrations of PEG. It is shown that the water2.2. Water content measurementcontent of the HA derivative films subjected towater swelling at 37C after cross-linking is higherSeveral pieces of dried cross-inked films ofthan 90% in weight if the PEG concentration is10 mmx10 mm were weighed and immersed inlower than approximately 0.5%. The sol fractionphosphate buffered saline(PBS: pH 7.45) at 37Cwas very low even when the water content of filmsfor 24 h. After removed from the saline solution,was as high as 95% in weight, probably because thethey were placed between 2 pieces of filter paper tosol fraction could not be determined precisely duewipe the excess solution, followed by weighing theto difficult extraction of water-soluble HA mole-water-swollen films. They were again dried in acules from the cross-linked HA hydrogels withvacuum oven for 6 h at 60C and then weighed tolower than 90% in weight, the apparent sol fractionestimate their solution fraction and water contentwas always close to zero. According to Fig. 1, weaccording to the following equations:Water content (%) = (Ws - Wd2)/Ws1)Where Wd and Wd2 are the weight of driedfilms before and after water swelling, and Ws is the1001:weight of swollen flms.802.3. Degradation of cross-linked HA films invitroThe cross-linked HA derivative films wereimmersed in phosphate buffered saline (PBS:20pH7.45) at 37C after measuring the weight. Thefilms were taken out at predetermined intervals ofttime and placed between 2 dry pieces of filter paperPEG coccentaioa(间)to wipe the excess solution from the films. The wetflms were weighed, dried in a vacuum oven for6hFig.1. Water content of HA flms cross linking withat 60"C and then weighed again to estimate the indifferent concentration of PEG at pH4.7, 6.0 and 8.0 forvitro degradation.120中国煤化工.0YHCNMHGChen Jnghua er al.Sournal of Medical Cllge ofPL4 232008)15-1917know that utilizing cross-linking method ofThe HA derivative flm cross-linked at pH 8.0,solution can produce cross-linked HA derivativewhich showed the slowest in vitro degradation inhydrogel films with water contents as low as 60%PBS (pH 7.45), was implanted subcutaneously inin weight, although it took 5 d to obtain such films.white rats to investigate in vivo degradation. TheIt is likely that the optimal pH of the castingweight percent of cross-linked HA derivative flmsolution for HA cross-linked by PEG is around 8.0,remaining after 2, 5 and 7 d of implantation isso that the PEG concentration is higher than aroundshown in Fig. 4. The HA derivative film Cross-1 %[4-6]. .linked with 0.36% PEG completely disappeared bybiodegradation at 6 d post-implantation. On the3.2. Degradation of cross linked HA filmcontrary, cross-linking of HA derivative with 3.6%PEG retarded the biodegradation more intensively.Degradation of cross-linked HA derivativeAfter 1 week of implantation, approximately 75%films was studied in aqueous media both in vitroof the cross-linked film still remained in theand in vivo. The degradation of cross-linked HAsubcutaneous tissue of rats. This is a similar resultderivative films in vitro was conducted by placingto that of in vitro degradation [9].them in PBS (pH 7.45) at 37C for2,5 and 10 d.The weight percent of HA derivative films4. Discussionremaining after immersion in PBS for these timeperiods is shown in Fig. 2 for HA derivative filmsThe chemical structurecross-linked at pH4.7, 6.0 and 8.0. The film CTOSS-linked at pH 4.7 shows the fastest degradation ratecross-inked by PEG was shown as Fig. 5. Accord-ing to the theory of polymer cross-linking incipientamong the three films, regardless of the PEGgelation, three dimensional networks take placeconcentration. The HA derivative film cross-linkedwhen one cross-linker is introduced in one polymerat pH8.0 with 3.6% PEG exhibits practically nomolecule. In the present case, this cross-linkerweight change for at least 10 d in PBS (pH 7.45) atconcentration corresponds to 3.6 x10-'% PEG,37C. Fig. 3 shows a plot of film weight remainingprovided all the cross-linker mole- cules addedafter immersion in PBS for different time periodshave effectively and quantitatively reacted with theagainst the water content of cross-linked HAHA molecules existing in the solution. However,derivative films. In spite of data scatter, it seemsthis will not be the case in the present study,probable that in vitro degradation of HA derivativebecause it is highly possible that only a smallfilms cross-linked with PEG is virtually governedfraction of PEG molcules can react with HAby the water content of films, which, in turn,molecules and that only a certain fraction of thedepends on the pH of the casting solution used fornew bonds formed would be effective for gelation.preparing cross-inked HA derivative flms [7, 8].A100BC80{i 80昌6o60! 40E 40020|isTimed)Time (d)Time(d)Fig. 2. In vitro degradation of HA flms cross-linked immersed in phosphate buffered saline (pH 7.45) at different PEGconcentration. A: pH 4.7; B: pH6.0; C: pH8.0.◆: 3.6%;■: 2.0%;▲: 0.8%.中国煤化工MHCNMHG18Chen Jinghua et al.J/oumal of Medical Clge ofPLA 232008)15-191401A1801BC160100口。140120-1508A口昆680-1060,4008主s02040 60) 100Water coatent(%)Water conteant(%)Fig. 3. In vitro degradation of HA flms eross-linked immersed in phosphate buffered saline (pH 7.45) at different immerseddays against the water content of HA crosslinked at dfferent pH values. A:2d; B:5d;C: 10d. O: 0.8%; 0:2.0%; O: 3.6%.One of the most important results in this studymodified PEG. And the chemical structure of HAis the success in preparing cross-linked HAderivative with longer chain is not easily destroyed.derivative films with equilibrated water contents asThis may be the reason why the HA filmaround low as 60% in weight. This low watercross-linked at pH 8.0 showed a lower watercontent can only be achieved with very high HAcontent than that formed at pH 6.0 as seen inconcentrations maintained during the reaction withfigurel. Meanwhile, it seems likely that the in vitroPEG, compared with those employed by otherdegradation of the cross-linked HA films inresearchers[10]. It is evident that the HA derivativeaqueous media proceeded not through the scissiotsolution can get high concentrations, similar to aof the cross-links but as a result of degradation ofHAcross-linking usingthe intact main chain of the cross-linked HAcarbodiimides [11]. The uncross-linked HA filmsmolecules, because HA is known to be susceptiblewill be also applicable for cross-linking with PEGto chain degradation. Additional enzymaticif reaction, which does not dissolve the films, isbiodegradation of HA main chains in vivo mayused, similar to HA cross-linking with carbo-explain the more remarkable degradation of thediimides.Cross-linked HA derivative is stable againstcross-inked HA in vivo than in vitro [12].It may be summarized that HA molecules canhydrolysis in aqueous solution of pH around 8.0,but is hydrolyzed at a lower pH (for example pHbe efficiently cross-linked with polyethylene glycol6.0 in this study). Therefore, it is possible that - -NHto produce a biodegradable, water-insoluble hydro-group of HA, which is easily obtained undergel material of low water content.alkaline condition, readily reacted with - C0o of1200080trspHHO~ CHOOH40co (CHz)2-C-O (CH2CH2O)一H^HN-HA2468Time(d)Fig.4. In vivo degradation of HA derivative filmsFig.5. Chemical structure of HA derivative cross-linkedcross-inked with different concentration of PEG for 120中国煤化工h pH6.0 after subcutaneous implantation in white rats;◆:0.36% PEG;■: 3.6% PEG."THCNMHGChen Jinghua e aLJournal of Medical Clleges ofPLA 232008)15- 191cytotoxicity of diepoxy compounds used forReferencesbiomaterial moditdification. J Biomed Mater Res 1995;29(6);: 829-834.1. Nicolai B. Rheologial studies of bartley (1-+3)8. Tokita Y, Okamoto A. Hyrolytie degration of(1- +4)-B-glucan in concentrated solution, mecha-hyaluronic acid. Polymer Degrad Stab 2005; 48(13):nistic and kinetic investigation of the gel formation.269-273.Carbohydr Res 1999; 315(7): 302-310.9. Fink RM, Lenfelder E. Hyaluronic acid degradation2. Kim BS, Mooney DI. Development of biocompatibleby ascorbic acid and influence of iron. Free Rad Ressynthetic extracellular matrices for tsseengineering.Commun 1987; 50(23): 85-92.Trends Biotechnol Inol 19998; 16 (5): 224- 229.10. Tomihata K, Burczak K, Shiraki K, et al. Cross-3.ChenJH,Xuz,GuQS,ctal.Researchonlinkingbiodegradation of native and denaturedrheologyical property of hyaluronic acid derivativecollagen. In; Polymers of Biological and Biomedicalcross-linked by polyethylene glycol.Sigaificance. Shalaby YSW, Lannger IR, Williams J,. Tongil Da XueXue Bao 2006; 34(1):ed. Washington DC: American Chemical Socier,4. Kenji Tomiats, Yoshito Ikada. Preparation of1994: 275-286.cross-linked hyaluronic acid fims of low water11. Laurence MP, Chu CC. Computational study of thecontent. J Biomaterials 1997; 18(3): 189-195.hyrolysis of degradable polysaccharide bio5. Schmut O, Ansari AN, Faulborn」Degradation ofmaterials: substituent effects on the hydrolytichyaluronate by the concerted action of ozone andmechanismComput Chem 2004; 15(9);: 241-248.sunlight. Ophthalmic Res 2002; 26(9): 340-343.12. Yui N, Okano T, SakuralY Regulated release of drug6. Kobayashi H, Shiraki K, Ikada Y. Toxicity test ofmicrospheres from inflammation responsivebiodegradable polymers by implantation in rabbitdegradable marices of erosslinked hyaluronie acid. Jcornea. J Biomed Mater Res 1992; 26(11): 1463-Contr Rel 1993; 25(5): 133-143.476.7. Nishi C, Nakajima N, Ikada Y. In vitro evaluation of(Editor Li Danyang)中国煤化工MHCNMHG

论文截图
版权:如无特殊注明,文章转载自网络,侵权请联系cnmhg168#163.com删除!文件均为网友上传,仅供研究和学习使用,务必24小时内删除。