本文選題：生物材料　切入點：骨修復(fù)材料　出處：《浙江大學(xué)》2012年碩士論文

【摘要】：促進或加速骨組織修復(fù)效能是當今骨修復(fù)材料研究重點。在骨修復(fù)材料中,鈦及鈦合金由于有良好的力學(xué)性能、生物相容性以及抗腐蝕能力,而被廣泛用于骨科及牙科手術(shù)中。但其生物活性以及與細胞響應(yīng)性較差,因此,提高鈦金屬植入體生物響應(yīng)性和生物活性因子/藥物承載性是當前研究熱點。 骨細胞外基質(zhì)主要由膠原蛋白等構(gòu)成,而羥基磷灰石(HA)是骨組織的主要無機成分。因此,在鈦表面構(gòu)建出膠原/HA復(fù)合(礦化)涂層,肯定能促進骨細胞吸附、生長及增殖,以及增加生物活性因子/藥物承載能力,從而有效提高植入體的骨整合能力和手術(shù)質(zhì)量。為此本文采用電化學(xué)沉積技術(shù),通過電沉積參數(shù)、電解液組成等調(diào)控,開展了鈦植入體可控制備礦化膠原涂層的研究。 在電化學(xué)沉積制備礦化膠原涂層過程中,對鈦基板采用堿熱處理,表面可形成多孔氧化層,可以有效提高沉積層的宏觀均勻性,這是由于多孔氧化層有利于電子的傳輸,同時為涂層中磷酸鈣和膠原分子的沉積提供了更大的比表面積,有利于涂層形成和結(jié)合強度的提高。沉積溫度會影響涂層的形貌及礦化磷酸鈣晶相的構(gòu)成,在37℃以上沉積時能獲得HA晶相,形成HA/膠原涂層。沉積電壓會影響涂層的形貌,在較高電壓下沉積形成多孔結(jié)構(gòu),在低電壓下涂層不能有效沉積。其原因為沉積電壓會改變陰極附近OH-濃度及分布,從而影響膠原的礦化和沉積行為。H2O2可作為電化學(xué)反應(yīng)增強劑,其加入會改變陰極電化學(xué)反應(yīng)類型,加速陰極處OH-的產(chǎn)生,在較短沉積時間和較低沉積電壓時可實現(xiàn)涂層的沉積,提高了涂層制備的可控性。當H202濃度為18 mM,電解液pH 4.5,沉積溫度37℃,在1.3～1.9 V時可制備致密礦化膠原涂層,在2～2.7 V時可制備多孔礦化膠原涂層。 本實驗中,多孔涂層和致密涂層的膠原纖維均為礦化形態(tài),多孔涂層膠原礦化程度高,膠原纖維分布比較分散,致密涂層膠原礦化程度低,HA結(jié)晶程度弱,膠原堆積致密。涂層斷面、剝離后各層形貌顯示多孔涂層和致密涂層均呈空間準三維結(jié)構(gòu),涂層厚度為20～30μm,靠近基底為HA層,中間層為HA與礦化膠原混合層,外層為礦化膠原層。力學(xué)性能測試表明礦化膠原涂層與基板有一定的結(jié)合力。 體外研究表明涂層在模擬體液中能穩(wěn)定存在并發(fā)生進一步礦化,表現(xiàn)出良好的生物活性。細胞實驗表明礦化膠原涂層能增加骨細胞的附著并促進其增殖。涂層可用作承載生物活性因子/藥物的平臺,實現(xiàn)抗菌藥物的裝載,釋放具有一定的緩釋能力,載萬古霉素后的涂層顯示了一定的殺菌效果。 通過對沉積過程的分段模擬,建立了電化學(xué)沉積機理的模型,即礦化膠原沉積可分為三個步驟：首先,磷酸鈣在鈦基板的迅速沉積,并伴隨膠原在等電點的自組裝；然后,磷酸鈣在膠原纖維上形核生長,形成膠原礦化；最終,礦化膠原在電場力的推動下向鈦基板移動,并與磷酸鈣層結(jié)合組裝在鈦基板上。膠原自組裝和礦化行為對礦化膠原涂層的沉積行為起著決定作用,因此,通過調(diào)控陰極pH梯度、膠原等電點是實現(xiàn)礦化膠原涂層可控制備的關(guān)鍵。
[Abstract]:Promoting and accelerating bone repair efficiency is the focus of the study. Bone repair materials in bone repair materials, titanium and titanium alloy with good mechanical properties, corrosion resistance and biocompatibility, and is widely used in Department of orthopedics and dental surgery. But its biological activity and the response is poor, and therefore improve the cell. Titanium implant biological response and biological factor / drug loading is the focus of current research.
The bone extracellular matrix composed mainly of collagen, and hydroxyapatite (HA) is the main inorganic composition of bone tissue. Therefore, the titanium surface modification with collagen /HA composite coating (mineralization), can promote bone cell adhesion, growth and proliferation, and increase the biological factor / drug carrying capacity, so as to effectively improve the bone integration ability and operation quality of the implant. This paper uses electrochemical deposition technique, by electrodeposition parameters, electrolyte composition and regulation, to carry out research on titanium implant preparation of mineralized collagen coatings.
In the electrochemical deposition preparation of mineralized collagen coating process on titanium substrate by alkali heat treatment, the surface can form a porous oxide layer, can effectively improve the macroscopic uniformity of deposition layer, which is due to the porous oxide layer is conducive to electronic transmission, at the same time for the deposition of calcium phosphate coating and collagen molecules provides greater the specific surface area, is conducive to the formation and improve the bonding strength of the coating. The deposition temperature can affect the morphology and mineralization of calcium phosphate crystal coating phase composition, can obtain the HA phase deposition in 37 degrees above, the formation of HA/ collagen coating. The deposition voltage will affect the morphology of the coatings, deposited to form a porous structure under relatively high voltage, an effective coating can not be deposited at a low voltage. The reason for the change of deposition voltage near the cathode of OH- concentration and distribution, thus affecting the.H2O2 mineralization and deposition of collagen can be used as an electrochemical reaction enhancer, which added Will change the electrochemical reaction type, accelerate the cathode OH-, deposited in a short deposition time and low deposition voltage can be realized when the coating, improve the controllability of coating preparation. When the concentration of H202 was 18 mM, 4.5 pH electrolyte, deposition temperature of 37 DEG C, in 1.3 ~ 1.9 V can be prepared preparation of mineralized collagen coating in 2 ~ 2.7 V can be prepared porous mineralized collagen coating.
In this experiment, porous coating and dense coating of collagen fibers were mineralized collagen morphology, porous coating of a high degree of mineralization, the collagen fibers distributed, dense coating mineralized collagen low degree of crystallinity of HA weak collagen accumulation density. After peeling off the coating section, each layer morphology shows that the porous coating and dense coating showed space quasi three dimensional structure, the thickness of the coating is 20~30 m, close to the substrate for the HA layer, the middle layer is HA and mineralized collagen mixed layer, the outer layer of mineralized collagen layer. The mechanical properties test showed that the mineralized collagen coating and substrate binding force.
In vitro studies showed that the coating can exist stably and further mineralization in SBF, showed good biological activity. The cellular experiments of mineralized collagen coating can increase the adhesion of osteoblasts and promote its proliferation. Coating can be used as a biological factor / drug loading platform, realize the antibacterial drug loading, release with sustained ability after coating, vancomycin showed some sterilization effect.
Through the simulation of segmented deposition process, established the mechanism of electrochemical deposition model, namely the mineralized collagen deposition can be divided into three steps: first, the rapid deposition of calcium phosphate on titanium substrate, and with the isoelectric point of collagen self-assembly; then, nucleation and growth of calcium phosphate in the form of collagen fibers, the formation of mineralized collagen finally, in the promotion of mineralized collagen; electric field force to the titanium substrate moving, and assembled on the titanium substrate and calcium phosphate layer. The deposition behavior of the self-assembly of collagen and mineralization behavior of mineralized collagen coating plays a decisive role, therefore, through the regulation of the cathode pH gradient isoelectric point of collagen, mineralized collagen is coating preparation of the key.

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

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本文編號：1676391