本文選題：可降解心血管支架 + 鎂合金　； 參考：《鄭州大學(xué)》2012年碩士論文

【摘要】：目前,臨床應(yīng)用的心血管支架均是不可降解的,作為異物在人體內(nèi)的長期存在引起了諸如血管再狹窄、形成血栓等一系列的問題,因此可降解支架的研究引起了廣泛關(guān)注。鎂合金具有優(yōu)良的綜合力學(xué)性能和生物相容性,并且能在人體內(nèi)降解,鎂離子也是人體所必須的離子,是作為可降解心血管支架的理想材料。但是鎂合金耐腐蝕性能很差,在體內(nèi)降解過快,有效服役期過短,不能滿足臨床要求,因此改善鎂合金的耐腐蝕性能顯得尤為重要。殼聚糖是一種具有優(yōu)良生物相容性的可降解天然高分子材料,已經(jīng)被廣泛的應(yīng)用于生物醫(yī)藥領(lǐng)域,通過對其進(jìn)行磺化處理能得到類肝素物質(zhì),此物質(zhì)擁有非常好的抗凝血性能,能有效地解決血管再狹窄和血栓形成的問題。本文利用浸涂法在鎂合金表面制備殼聚糖和磺化殼聚糖涂層,以及復(fù)合涂層,重點(diǎn)研究了涂層的表面特性及通過各種處理后鎂合金在模擬體液中的耐腐蝕性能。 實(shí)驗(yàn)表明,不同濃度的殼聚糖溶液粘度不同,在鎂合金表面制備的殼聚糖涂層的致密度和表面平整度等不同,濃度0.5%的殼聚糖溶液比較稀,形成的膜致密度較差,表面氣孔較多較大,容易產(chǎn)生微電池效應(yīng)；濃度1.5%的殼聚糖溶液粘度大,形成的涂層表面平整度差,溶脹率大,容易產(chǎn)生脫落；濃度為1.0%的殼聚糖溶液形成的涂層致密平整,綜合性能好,對鎂合金的保護(hù)作用明顯,可以通過改變浸涂次數(shù)來控制涂層厚度,浸涂3、5和7次得到的涂層的厚度分別為70μm、85μm和100μm。 鎂合金活化后,能增大涂層與基體的結(jié)合面積,減弱酸性涂層和基體的析氫反應(yīng),并引入大量活性-OH,從而增強(qiáng)結(jié)合強(qiáng)度,改善鎂合金的耐腐蝕性能,活化消耗一定量的基體材料,因此控制活化的程度至關(guān)重要。 實(shí)驗(yàn)表明,在鎂合金表面先形成一層偶聯(lián)劑涂層,偶聯(lián)劑與鎂合金表面形成Si-O共價(jià)鍵,從而增強(qiáng)結(jié)合強(qiáng)度。與利用無水乙醇為溶劑的硅烷偶聯(lián)劑相比,去離子水為溶劑的硅烷偶聯(lián)劑表現(xiàn)出更好的性能,但是會引起涂層較大面積的脫落,以乙醇為溶劑的偶聯(lián)劑溶液產(chǎn)生的膜有優(yōu)良的綜合性能,預(yù)先進(jìn)行活化處理后,能提供更多的接觸面積和羥基。 對鎂合金進(jìn)行交聯(lián)處理,能夠得到表面平整度很高的涂層,結(jié)合強(qiáng)度也大大提高,因?yàn)槲於┲械娜┗c殼聚糖中的氨基形成—C=N—鍵,使殼聚糖分子鏈相互結(jié)合成網(wǎng)狀結(jié)構(gòu),溶脹率大大減小,減弱了由于溶脹引起的涂層脫落,殼聚糖膜的交聯(lián)在一定程度上增加了鎂合金的絲狀腐蝕,且會影響到殼聚糖的活性,因此戊二醛的加入比例應(yīng)該嚴(yán)格控制。 在殼聚糖上面接枝磺酸基,磺酸基有吸附金屬離子的傾向,相當(dāng)于在殼聚糖涂層上分布著很多吸附點(diǎn),能一定程度的增強(qiáng)結(jié)合強(qiáng)度,改善耐腐蝕性能。由紅外光譜可知磺化殼聚糖的結(jié)構(gòu)與肝素的結(jié)構(gòu)非常相似,在波數(shù)804.2cm-1和1224.6cm-1處均出現(xiàn)明顯的峰,說明在3,6位都成功接枝了磺酸基團(tuán),已被證實(shí)有很好的抗凝血性能。 殼聚糖/磺化殼聚糖層層自組裝膜是利用兩種化合物帶有不同的電荷而產(chǎn)生的靜電力及分子鏈纏繞為結(jié)膜動力,在保持磺化殼聚糖好的抗凝性能的同時(shí),還能極大的改善鎂合金的抗腐蝕性能,其開路電位達(dá)到-0.9V左右,在模擬體液中浸泡120h對其pH值影響最大不超過0.4,體現(xiàn)出了優(yōu)越的保護(hù)性能。 材料的親水性越好,其抗凝血性能越好。單純的殼聚糖膜的親水性不好,接觸角為83°,對鎂合金表面進(jìn)行偶聯(lián)、交聯(lián)處理后均對殼聚糖膜親水性有一定的改善作用,接觸角分別為76.5°和52.5°,對殼聚糖進(jìn)行磺化改性,制成的磺化殼聚糖膜有很好的親水性,接觸角為27°,殼聚糖/磺化殼聚糖層層自組裝膜的接觸角為57°。
[Abstract]:The present invention relates to a degradable natural polymer material with excellent biocompatibility , which has excellent comprehensive mechanical property and biocompatibility , and can be used as ideal material for degradable cardiovascular stent .

The results showed that different concentration of chitosan solution had different viscosity , the density of chitosan coating prepared on the surface of magnesium alloy was different , and the concentration of chitosan solution was 0.5 % .
the viscosity of the chitosan solution with the concentration of 1.5 percent is large , the surface smoothness of the formed coating is poor , the swelling rate is large , and the chitosan solution is easy to generate and fall off ;
The coating prepared by chitosan solution with the concentration of 1.0 % is compact and flat , the comprehensive performance is good , the protective effect on the magnesium alloy is obvious , the thickness of the coating can be controlled by changing the number of dip coating , and the thickness of the coating obtained by dip coating 3 , 5 and 7 times is 70 . m u.m , 85 . m u.m and 100 . m

After the magnesium alloy is activated , the bonding area of the coating and the substrate can be increased , the hydrogen evolution reaction of the acid coating and the substrate is weakened , and a large amount of active - OH is introduced , so that the bonding strength is enhanced , the corrosion resistance of the magnesium alloy can be improved , and a certain amount of matrix material is consumed , so that the degree of activation is controlled .

Compared with the silane coupling agent using absolute ethyl alcohol as solvent , the silane coupling agent with deionized water as solvent shows better performance , but it can cause the coating to fall off , and the film produced by the coupling agent solution with ethanol as solvent has excellent comprehensive performance , and can provide more contact area and hydroxyl group after the activation treatment is carried out in advance .

the crosslinking treatment of the magnesium alloy can obtain the coating with high surface flatness and greatly improve the bonding strength ; because the aldehyde group in the glutaraldehyde and the amino group in the chitosan form - C = N - bond , the chitosan molecular chains are combined into a net structure , the swelling rate is greatly reduced , the silk corrosion of the magnesium alloy is increased to a certain extent , and the crosslinking of the chitosan film can influence the activity of the chitosan , so that the adding proportion of glutaraldehyde should be strictly controlled .

The results show that the structure of sulfonated chitosan is very similar to that of heparin , which shows that the structure of sulfonated chitosan is very similar to the structure of heparin . It shows that the structure of sulfonated chitosan is very similar to the structure of heparin .

The chitosan / sulfonated chitosan layer self - assembly film is characterized by that the electrostatic force and the molecular chain generated by the chitosan / sulfonated chitosan layer self - assembly film are wound into conjunctival power by using two compounds with different electric charges , and the corrosion resistance performance of the magnesium alloy can be greatly improved while maintaining the anti - coagulation property of the sulfonated chitosan , and the open - circuit potential of the chitosan / sulfonated chitosan layer self - assembly film is about - 0.9V , and the influence on the pH value of the chitosan / sulfonated chitosan layer self - assembly film is not more than 0.4 , and the excellent protection performance is shown .

The better the hydrophilicity of the material , the better the anticoagulant properties . The hydrophilic property of the chitosan membrane was not good , the contact angle was 83 擄 , and the surface of the magnesium alloy was coupled . After crosslinking treatment , the hydrophilicity of chitosan membrane was improved . The contact angle was 76.5 擄 and 52.5 擄 , and the contact angle was 76.5 擄 and 52.5 擄 respectively . The sulfonated chitosan membrane prepared by sulfonation modified the chitosan membrane has a good hydrophilicity . The contact angle is 27 擄 . The contact angle of chitosan / sulfonated chitosan layer self - assembly film is 57 擄 .

【學(xué)位授予單位】：鄭州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2012
【分類號】：R318.08

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 鄧景發(fā);;研究金屬腐蝕的一些電化學(xué)方法——一、極化曲線法[J];材料保護(hù);1965年04期

2 許鑫華;程靜;張春懷;閆學(xué)良;朱天兵;姚康德;曹路;劉寅;;醫(yī)用鎂合金的生物腐蝕及高分子涂層處理[J];稀有金屬材料與工程;2008年07期

3 朱孔營;渠榮遴;李方;;低分子量殼聚糖制備與應(yīng)用研究進(jìn)展[J];高分子通報(bào);2006年02期

4 曹燕琳;尹靜波;顏世峰;;生物可降解聚乳酸的改性及其應(yīng)用研究進(jìn)展[J];高分子通報(bào);2006年10期

5 周永國;楊越冬;侯文龍;于九皋;;化學(xué)修飾殼聚糖的血液相容性[J];高分子通報(bào);2008年06期

6 陳文平;江貴林;汪超;倪學(xué)文;李東生;姜發(fā)堂;;天然高分子材料作為藥物緩控釋載體應(yīng)用的研究進(jìn)展[J];海峽藥學(xué);2009年11期

7 王碧,葉勇,程勁,張廷有,但衛(wèi)華,王坤余;膠原蛋白制備生物醫(yī)學(xué)材料的特征及改性方法[J];化學(xué)世界;2003年11期

8 李海偉;徐克;楊柯;劉靜;張炳春;夏永輝;鄭豐;韓洪波;譚麗麗;洪鐸;顏廷亭;;可降解AZ31鎂合金支架在兔腹主動脈的降解性能研究[J];介入放射學(xué)雜志;2010年04期

9 樓白楊;高貴斌;繆克在;徐斌;;AZ91D鎂合金表面聚氨酯涂層耐腐蝕性能[J];材料熱處理學(xué)報(bào);2009年05期

10 沈華;沈尊理;陳南j;孫丹丹;祝家學(xué);張佩華;;不同濃度殼聚糖涂層PLGA材料與許旺細(xì)胞相容性研究[J];中國美容醫(yī)學(xué);2009年11期

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