摘 要:為解決傳統(tǒng)海藻酸鈣止血海綿工藝復(fù)雜、耗時(shí)過(guò)長(zhǎng)的問(wèn)題,以殼聚糖、碳酸鈣、海藻酸鈉和甘油為原料,通過(guò)離子交聯(lián)、內(nèi)凝膠法經(jīng)一步冷凍干燥工藝得到具有多孔結(jié)構(gòu)的止血海綿,并通過(guò)吸液率測(cè)試、保水率測(cè)試、水蒸氣透過(guò)率測(cè)試和電子萬(wàn)能拉力機(jī)測(cè)試分析CaCO3含量對(duì)殼聚糖/海藻酸鈣海綿吸液性能、力學(xué)性能、透氣性能和保水性能的影響,同時(shí)探討了Ca2+的釋放促進(jìn)機(jī)體自身的凝血機(jī)制。結(jié)果表明:該海綿的溶血率在2%以下,凝血指數(shù)可達(dá)到13%左右,具有較好凝血效果和生物相容性,在止血海綿敷料方面有很大應(yīng)用前景。
關(guān)鍵詞:碳酸鈣;殼聚糖;海藻酸鈉;止血海綿;體外凝血;液體吸收
中圖分類(lèi)號(hào):TS102.5
文獻(xiàn)標(biāo)志碼:A
文章編號(hào):1009-265X(2025)03-0008-08
收稿日期:2024-07-25 網(wǎng)絡(luò)出版日期:2024-09-23
基金項(xiàng)目:國(guó)家自然科學(xué)基金項(xiàng)目(52003108)
作者簡(jiǎn)介:羅爽(2000—),女,河南南陽(yáng)人,碩士研究生,主要從事功能紡織品材料方面的研究
通信作者:王鴻博,E-mail:wxwanghb@163.com
快速有效止血是降低日常生活和臨床手術(shù)中造成出血死亡率的主要途徑[1]。目前市場(chǎng)上使用較廣泛的止血材料有海綿、水凝膠和微球等多種形態(tài),這些材料主要是由多糖、硅鋁酸鹽和納米自組裝肽等組成[2]。理想的止血材料應(yīng)具備止血迅速、可生物降解、無(wú)毒性和良好的機(jī)械性能等特點(diǎn)。海綿材料因具有相互連接的多孔結(jié)構(gòu)和高吸水性使其適合防止傷口滲出物的積聚,是生物材料領(lǐng)域最有前途的止血敷料之一[3-4]。理想的敷料應(yīng)保持傷口界面濕潤(rùn)的環(huán)境,允許氣體交換,并吸取多余的滲出物[5]。另外止血材料還必須具備一定的機(jī)械強(qiáng)度、三維網(wǎng)絡(luò)和良好的保形性[6]。使用過(guò)的敷料應(yīng)易于去除而不會(huì)造成傷口二次創(chuàng)傷,以促進(jìn)新組織的產(chǎn)生[7]。
殼聚糖(Chitosan,CS)具有毒性低、吸附性強(qiáng)、生物相容性好以及可降解等優(yōu)點(diǎn),其獨(dú)特的抗菌性、凝血性和促進(jìn)愈合使其在止血領(lǐng)域有巨大潛力[8-9]。海藻酸鈉(Sodium alginate,SA)是一種天然可降解多糖,具有促進(jìn)傷口愈合、保濕和吸濕等功能[10]。海藻酸鹽與金屬離子交聯(lián)形成的水凝膠、微球體和海綿是其用于動(dòng)脈栓塞止血和組織黏合的常用形態(tài)[11]。Ca2+作為外源凝血因子可通過(guò)加快血小板聚集和充當(dāng)凝血途徑中的輔助因子激活凝血過(guò)程[12]。傳統(tǒng)的海藻酸鈣海綿常用海藻酸鈉與CaCl2交聯(lián)形成“蛋盒結(jié)構(gòu)”制備海綿敷料,需要成形后再次以外凝膠法浸泡在氯化鈣溶液中交聯(lián),以維持穩(wěn)定結(jié)構(gòu),經(jīng)兩步冷凍干燥成形,具有工藝流程復(fù)雜、耗時(shí)過(guò)長(zhǎng)和海綿結(jié)構(gòu)脆性大等問(wèn)題,且由于氯化鈣溶解度高在弱酸環(huán)境中會(huì)導(dǎo)致凝膠化反應(yīng)過(guò)快,難以控制凝膠成型速度容易造成結(jié)構(gòu)不勻。碳酸鈣具有優(yōu)異的生物相容性、簡(jiǎn)單的化學(xué)成分、適宜的生物降解率和易于大規(guī)模生產(chǎn)等優(yōu)點(diǎn),且碳酸鈣的難溶性使其可通過(guò)調(diào)控pH值來(lái)控制溶解度來(lái)緩釋Ca2+,因此近年來(lái)在止血敷料方面越來(lái)越受到關(guān)注。
為制備柔軟親膚、快速止血的海綿敷料,本文擬選取海藻酸鈉與殼聚糖為基礎(chǔ)材料,應(yīng)用內(nèi)凝膠法于弱酸性環(huán)境中處理海綿前驅(qū)體溶液,促使海藻酸鈉與碳酸鈣之間形成離子交聯(lián)網(wǎng)絡(luò),并同時(shí)誘導(dǎo)海藻酸鈉與殼聚糖之間產(chǎn)生靜電相互作用,進(jìn)而構(gòu)建出穩(wěn)定的交聯(lián)結(jié)構(gòu)。隨后,采用真空冷凍干燥技術(shù),對(duì)這一交聯(lián)網(wǎng)絡(luò)進(jìn)行固化處理,以期制備出能夠形態(tài)穩(wěn)定、快速吸液、快速止血和安全無(wú)毒的多孔海綿。本文研究方法有望改善傳統(tǒng)工藝中浸泡交聯(lián)的外凝膠手段使海綿手感變硬的問(wèn)題,同時(shí)縮短工藝流程,可為海藻酸鈉在生物敷料的應(yīng)用和開(kāi)發(fā)提供一種新的途徑。
1 實(shí)驗(yàn)
1.1 試劑與儀器
試劑:殼聚糖(CS,中粘度:200~400 CPS,北京伊諾凱科技有限公司);海藻酸鈉(SA,低粘度:20~100 CPS,中國(guó)阿拉丁試劑有限公司);碳酸鈣(CaCO3,國(guó)藥集團(tuán)化學(xué)試劑有限公司);甘油(GLY,≥99.5%,上海麥克林生化科技股份有限公司);無(wú)水乙醇(AE,中國(guó)國(guó)藥集團(tuán)化學(xué)試劑有限公司);溶菌酶(中國(guó)國(guó)藥集團(tuán)化學(xué)試劑有限公司);磷酸緩沖液(PBS,中國(guó)國(guó)藥集團(tuán)化學(xué)試劑有限公司);去離子水(使用ULUPURE純水/水系統(tǒng)自制)。
儀器:SU1510型掃描電子顯微鏡(日本日立株式會(huì)社);QWZY-X3恒溫培養(yǎng)箱(太倉(cāng)市強(qiáng)文實(shí)驗(yàn)設(shè)備有限公司);SCIENTZ-10N冷凍干燥機(jī)(寧波新芝凍干設(shè)備股份);Nicoletis10型傅里葉變換紅外光譜儀(美國(guó)賽默飛世爾科技有限公司);MULTISKANGO-1510酶標(biāo)儀(美國(guó)賽默飛世爾科技有限公司)。
1.2 殼聚糖/海藻酸鈉/CaCO3海綿的制備
稱(chēng)取質(zhì)量分?jǐn)?shù)均為1%的CS和SA溶解在pH 4.5的乙酸-乙酸鈉緩沖液中制成混合溶液。取一定量的CaCO3粉末加入到去離子水中,于渦旋儀中混勻配制懸浮液;將其加入所制備的混合溶液中,攪拌均勻后加入質(zhì)量分?jǐn)?shù)2%的甘油繼續(xù)反應(yīng)1 h。記不含CaCO3的樣品為CA0;記CaCO3質(zhì)量分?jǐn)?shù)為0.2%、0.4%、0.6%和0.8%的樣品為CA1、CA2、CA3和CA4。將此混合溶液在4℃靜置24 h,之后在-20℃冷凍,最后冷凍干燥(-60℃,48 h)得到海綿狀敷料。
1.3 結(jié)構(gòu)表征
1.3.1 傅里葉變換紅外光譜測(cè)試
采用傅里葉變換紅外光譜儀對(duì)海綿進(jìn)行測(cè)試,室溫下在范圍4000~500 cm-1內(nèi)進(jìn)行掃描。
1.3.2 表面形貌測(cè)試(SEM)
通過(guò)場(chǎng)發(fā)射掃描電子顯微鏡觀測(cè)海綿的截面。
1.4 性能表征
1.4.1 密度和孔隙率
在干燥狀態(tài)下稱(chēng)取樣品重量記為W0,計(jì)算出體積(V),然后浸泡至無(wú)水乙醇溶液中直至飽和(ρ=0.7893 g/cm3),稱(chēng)其重量記為W1。用式(1)計(jì)算孔隙率(P):
P/%=W1-W0ρV×100(1)
1.4.2 吸液性能和保水性能
然后將樣品浸沒(méi)在純水中至其達(dá)到溶脹平衡,稱(chēng)取吸液后的樣品重量,記為W2。吸液率(A)按式(2)計(jì)算:
A/%=W2-W0W0×100(2)
將樣品浸泡在純水中24 h后以1000 r/min離心10 min稱(chēng)重,記為W3。保水率(B)按式(3)計(jì)算:
B/%=W3-W0W0×100(3)
1.4.3 力學(xué)性能
將樣品制成圓柱形,采用電子萬(wàn)能試驗(yàn)機(jī)以10 mm/min 的壓縮速度使其形變達(dá)到80%的應(yīng)變。
1.4.4 體外降解性能
將海綿浸泡在含有溶菌酶(104 U/mL)的磷酸緩沖液中,在37℃下孵育。記海綿的初始重量為W0,在固定時(shí)間間隔取出樣品干燥稱(chēng)重,記為W4。海綿的降解以其在不同時(shí)間的失重率來(lái)表示,降解率(D)可通過(guò)式(4)來(lái)計(jì)算:
D/%=W0-W4W0×100(4)
1.4.5 水蒸氣透過(guò)率
將海綿包裹在含有去離子水的圓柱形杯口中,以不含海綿樣品包裹杯口的測(cè)試樣為空白組進(jìn)行對(duì)照實(shí)驗(yàn)。在恒溫恒濕箱(37℃,75%)中保存24 h。測(cè)定杯中水的質(zhì)量損失,通過(guò)以下式(5)進(jìn)行計(jì)算:
T=24×(W0-W5)A×t(5)
式中:T為水蒸氣透過(guò)率,g/(m2·d);A為杯床面積,m2;t為時(shí)間間隔,h;W0為初始重量,g;W5為在恒溫恒濕箱中不同時(shí)間間隔后的重量,g。
1.4.6 溶血率測(cè)試
將新鮮抗凝血和PBS混合離心,紅細(xì)胞與PBS按1∶34的比例混合,得到富紅細(xì)胞血漿。將不同濃度的海綿浸提液與紅細(xì)胞共混,并在37℃的搖床中以120 r/min培養(yǎng)。然后將混合物離心。用酶標(biāo)儀測(cè)定上清液在540 nm處的吸光度。純水(DW)和PBS為陽(yáng)性對(duì)照和陰性對(duì)照。溶血率通過(guò)公式(6)來(lái)計(jì)算:
H/%=As-AnAp-An×100(6)
式中:H為溶血率,%;As為樣品上清液的吸光度;An為陰性對(duì)照組上清液的吸光度;Ap為陽(yáng)性對(duì)照組上清液的吸光度。
1.4.7 凝血指數(shù)(BCI)測(cè)試
將海綿和止血紗布置于培養(yǎng)板上,在37℃下預(yù)熱5 min后加入抗凝血液,將CaCl2溶液滴入混合物中,在37℃下孵育后將PBS滴入培養(yǎng)板中。最后,測(cè)定含血紅蛋白的洗滌溶液在540 nm的吸光度。選擇不含樣品的測(cè)試樣為陰性對(duì)照組。凝血指數(shù)的計(jì)算如式(7)所示:
BCI/%=DsDn×100(7)
式中:BCI表示凝血指數(shù),%;Ds表示海綿樣品組的吸光度;Dn表示陰性對(duì)照組的吸光度。
2 結(jié)果與分析
2.1 紅外光譜(FTIR)分析
SA、CS原料和CA2海綿的紅外光譜如圖1所示。SA的紅外光譜線在1590 cm-1和1411 cm-1處有明顯的吸收峰,分別對(duì)應(yīng)羧基的不對(duì)稱(chēng)和對(duì)稱(chēng)伸縮振動(dòng)[13]。CS上1628 cm-1和1583 cm-1處的峰分別屬于—CO伸縮(酰胺Ⅰ)和—NH(酰胺Ⅱ)彎曲振動(dòng)[14]。從CA2海綿的紅外光譜看在1552 cm-1和1327 cm-1處新出現(xiàn)的峰,分別為伯酰胺即酰胺Ⅰ帶的強(qiáng)吸收峰和—NH與—C—N之間偶合造成的酰胺Ⅱ帶與酰胺Ⅲ帶的吸收峰,說(shuō)明CS的—NH2在酸性條件下轉(zhuǎn)化為—NH+并與SA的—COO-發(fā)生靜電相互作用。在3280 cm-1處發(fā)現(xiàn)的海綿的—OH振動(dòng)峰增強(qiáng),表明海綿的體系中存在分子間氫鍵。SA在1590 cm-1處屬于—C—O的伸縮振動(dòng)特征峰在CA2海綿中往1647 cm-1處移動(dòng),證明SA的羧酸根離子和Ca2+之間形成了離子鍵。
2.2 形貌分析
從宏觀和微觀層面觀察海綿的形貌結(jié)構(gòu),海綿的表觀形貌如圖2所示,從宏觀層面看,3種海綿的表觀形貌差別不大,都呈現(xiàn)質(zhì)地均勻,蓬松柔軟的狀態(tài)。為探究Ca2+對(duì)海綿內(nèi)部孔洞結(jié)構(gòu)分布的影響,在放大100倍的低倍數(shù)下觀察海綿的橫截面結(jié)構(gòu)。從圖2可以看出,CA0、CA1、CA3和CA4海綿的內(nèi)部結(jié)構(gòu)呈現(xiàn)片層堆疊狀,孔洞結(jié)構(gòu)不明顯;CA2海綿的孔隙結(jié)構(gòu)比較明顯,呈現(xiàn)出不規(guī)則的三維互連孔洞,孔隙大小不規(guī)則且隨機(jī)排布。這表明Ca2+的含量是影響離子交聯(lián)和海綿孔徑的主要因素,Ca2+含量過(guò)高或過(guò)低均會(huì)使海綿無(wú)法形成三維孔洞,從而影響海綿的吸液性能和孔隙率等性能指標(biāo)。
2.3 密度和孔隙率分析
孔隙率是止血敷料的基本特征,海綿敷料在實(shí)際應(yīng)用中應(yīng)能夠更好地吸收滲出液,并具有足夠的孔隙率以進(jìn)行營(yíng)養(yǎng)和氣體的交換[15]。海綿敷料的孔隙率接近80%時(shí)有利于藥物釋放,且吸水性和保水率良好。海綿的密度與孔隙率如圖3所示,隨著樣品密度的增加孔隙率明顯降低,CA1、CA2和CA3的孔隙率分別為(86±3.43)%、(94±3.75)%和(88±3.52)%,CA0的孔隙率為(43±1.69)%。不含Ca2+的海綿孔隙率明顯低于其他海綿,這表明離子交聯(lián)有助于網(wǎng)絡(luò)結(jié)構(gòu)的形成使海綿的孔洞增多,因此孔隙率增大。海綿孔隙率較高時(shí)內(nèi)部孔洞結(jié)構(gòu)增多,因此相同體積下質(zhì)量較小,密度較低,因此海綿的孔隙率與密度呈相反趨勢(shì)。較高的孔隙率有助于使傷口保持在潤(rùn)濕環(huán)境中,促進(jìn)細(xì)胞增殖和
傷口愈合,因此Ca2+質(zhì)量分?jǐn)?shù)為0.2%、
0.4%和0.6%時(shí)海綿性能較好。
2.4 海綿的吸液性能分析
傷口敷料的吸水和保水能力是評(píng)估清除傷口滲出液和維持潤(rùn)濕環(huán)境以利于傷口愈合和防止結(jié)痂功效的關(guān)鍵指標(biāo)[16]。臨床應(yīng)用時(shí)有急性壓力使用的情況,例如,壓在完全飽和的敷料上,總吸收量和加壓下保留吸收液體的能力尤為重要,以評(píng)估完整敷料的鎖液性能。海綿類(lèi)止血敷料所吸收液體能達(dá)到自身重量的10倍以上時(shí)表明其具有良好的液體吸收效果。如圖4(a)所示,CA0海綿中沒(méi)有Ca2+參與交聯(lián)反應(yīng),海綿結(jié)構(gòu)不穩(wěn)定,遇水無(wú)法保形不具備吸液性能。其他海綿中海藻酸鈉與乙酸所含的CH3COO-與殼聚糖的氨基結(jié)合,同時(shí)與Ca2+產(chǎn)生離子交聯(lián)形成三維網(wǎng)絡(luò)結(jié)構(gòu),使海綿形成孔隙結(jié)構(gòu),因此吸液性能較好。其中CA1和CA2海綿的吸液率較好,在24 h后達(dá)到1213%±48.52%和1234%±49.36%。如圖4(b)所示,隨著CaCO3含量增加海綿的保水率呈逐漸下降的趨勢(shì),這是因?yàn)楹>d的內(nèi)部分子交聯(lián)程度過(guò)高,形成的孔隙小且密集吸液率下降,并且較小的孔隙有助于水分的擴(kuò)散,因此保水能力下降。CA1和CA2由于其吸液性能好,海綿
的膨脹系數(shù)高,因此最終保水率略高。
2.5 力學(xué)性能分析
傷口敷料應(yīng)具有一定機(jī)械性能使其在遭受外部應(yīng)力時(shí)保持完整性以避免皮膚傷口受到損傷,在用于止血時(shí)海綿材料需與創(chuàng)口緊密接觸,海綿具有適當(dāng)?shù)膲嚎s性能,一則方便攜帶使用,經(jīng)壓縮后吸液膨脹可對(duì)出血部位起到壓迫作用以有效控制出血;二則柔軟的海綿材料可以減輕對(duì)傷口的傷害,便于適應(yīng)不規(guī)則傷口。因此對(duì)海綿敷料的壓縮性能進(jìn)行測(cè)試[17]。由于該海綿不具備吸水膨脹性,液體吸收對(duì)其承壓能力沒(méi)有顯著影響,因此一般采用干態(tài)下的海綿測(cè)試其機(jī)械強(qiáng)度。海綿的壓縮應(yīng)力應(yīng)變曲線如圖5所示,CA1-CA4四種海綿在干燥狀態(tài)下的壓縮應(yīng)力均在壓縮形變達(dá)到70%時(shí)增加明顯,表明其均具有一定的柔韌度和機(jī)械強(qiáng)度,其中CA2海綿(Ca2+含量為0.4%)的壓縮強(qiáng)度明顯高于其他海綿,這主要是因?yàn)镃aCO3含量對(duì)海綿的機(jī)械強(qiáng)度有較大影響。當(dāng)Ca2+含量較低,離子交聯(lián)程度較弱,海綿內(nèi)部結(jié)構(gòu)不穩(wěn)定、支撐度不足導(dǎo)致海綿過(guò)于柔軟、機(jī)械強(qiáng)度較差;隨著Ca2+含量增加,其離子交聯(lián)程度增加,可有效提高海綿的機(jī)械性能;但當(dāng)Ca2+含量過(guò)高時(shí)也會(huì)打破離子交聯(lián)的平衡點(diǎn),過(guò)量的CaCO3會(huì)殘存在內(nèi)部結(jié)構(gòu)中阻止海藻酸鈉上的羧基與殼聚糖上的氨基進(jìn)一步結(jié)合,從而使化學(xué)交聯(lián)程度降低,機(jī)械性能下降,因此,Ca2+
含量為0.4%時(shí)海綿的力學(xué)性能較好。
2.6 水蒸氣透過(guò)性能分析
合適的水蒸氣透過(guò)性能對(duì)傷口的愈合至關(guān)重要,過(guò)高的水蒸氣透過(guò)率會(huì)導(dǎo)致疤痕的生成,過(guò)低的水蒸氣透過(guò)率則會(huì)導(dǎo)致滲出物的累積增加細(xì)菌感染的風(fēng)險(xiǎn)。據(jù)報(bào)道,傷口敷料的水蒸氣透過(guò)率在500~5000 g/(m2·d)之間可以有效地保持傷口周?chē)臐穸群蜌怏w交換[18]。如圖6所示,海綿的水蒸氣透過(guò)率隨著Ca2+含量的增加呈現(xiàn)先增后減的趨勢(shì),這與海綿的孔隙率變化有一定關(guān)系,最終海綿的水蒸氣透過(guò)率均在2000~3000 g/(m2·d),適合皮膚傷口愈合的條件。
2.7 體外降解性能分析
海綿敷料的生物降解性能對(duì)細(xì)胞外基質(zhì)的形成和皮膚修復(fù)有重要意義,止血后應(yīng)及時(shí)對(duì)止血海綿進(jìn)行生物降解,防止體內(nèi)殘留的止血材料引起組織炎癥并阻止黏膜再生[19]。由于CA0海綿中不含Ca2+參與交聯(lián),在降解實(shí)驗(yàn)中浸泡后分散溶解,因此無(wú)法計(jì)算21 d周期內(nèi)的降解變化。海綿在PBS-溶菌酶中的體外降解曲線如圖7所示,21 d后所有海綿的失重率均達(dá)到了60%以上,其中CA1和CA2海綿的降解性能較好在21 d后失重率達(dá)到了73.155%±2.924%和76.708%±2.302%,這表明海綿具有良好的體外降解性能,在止血敷料上有一定的應(yīng)用潛力。
2.8 溶血性能分析
止血材料應(yīng)該在止血過(guò)程中接觸血液引發(fā)凝血而不破壞血細(xì)胞引發(fā)溶血[20]。海綿與紗布的溶血率如圖8所示,所有海綿溶血率均低于生物材料血液相容性評(píng)價(jià)的最低標(biāo)準(zhǔn)(5%),表明海綿具有良好的生物相容性。海綿在濃度為10 mg/mL時(shí)溶血率最高值為0.375%±0.027%,在較低濃度下的溶血率最低值為0.117%±0.024%;海綿與血液反應(yīng)24 h后溶血率均有所上升但仍在2%以下,與醫(yī)用棉紗布相比海綿具有更小的溶血率表明其細(xì)胞毒性更低。綜上,海綿具有較好的生物相容性,安全無(wú)毒,具有生物止血材料的應(yīng)用潛力。
2.9 海綿的體外凝血指數(shù)測(cè)試分析
海綿的止血能力可以通過(guò)凝血試驗(yàn)來(lái)檢測(cè),BCI值越低止血性能越好[21]。如圖9所示,海綿的BCI值均在30%以下且明顯低于醫(yī)用棉紗布,表明海綿的止血性能較好。在凝血時(shí)間為5 min時(shí),隨著Ca2+含量的增加凝血指數(shù)逐漸降低,可能是因?yàn)镃a2+釋放作為凝血因子引發(fā)了外源凝血途徑,加速凝血。凝血時(shí)間為30 min時(shí)所有海綿的BCI值相差不大且均低于20%,其中CA2的凝血指數(shù)為13.924%±0.963%,表明海綿有短時(shí)間快速凝血的潛力。
3 結(jié)論
本文利用殼聚糖、海藻酸鈉及碳酸鈣作為主要材料,成功制備了止血海綿。在制備過(guò)程中,鈣離子不僅作為關(guān)鍵止血因子,顯著增強(qiáng)了止血效果,還促進(jìn)了離子交聯(lián)反應(yīng),從而構(gòu)建了穩(wěn)固的凝膠化結(jié)構(gòu)。隨后,通過(guò)一步冷凍干燥工藝,這一凝膠結(jié)構(gòu)被塑形為海綿狀敷料,實(shí)現(xiàn)了高效止血與良好形態(tài)的雙重目標(biāo)。本文對(duì)海綿的一些性能進(jìn)行了測(cè)定,包括液體吸收能力、機(jī)械性能、水蒸氣透過(guò)率、止血性能和體外降解性能。主要結(jié)論如下:
a)當(dāng)CaCO3質(zhì)量分?jǐn)?shù)為0.4%時(shí),所制海綿的性能較好,吸液率為1234%±49.36%,孔隙率為94%±3.75%,凝血指數(shù)為13.924%±0.963%,體外降解率為76.708%±2.302%。
b)通過(guò)弱酸調(diào)控pH值來(lái)促使碳酸鈣電離,進(jìn)而引發(fā)離子交聯(lián)反應(yīng),簡(jiǎn)化了制備流程,僅需一步冷凍干燥工序,即可高效產(chǎn)出性能優(yōu)異的海綿產(chǎn)品。這種內(nèi)凝膠化方式制備的海綿展現(xiàn)出更加柔軟和親膚的特性,在止血過(guò)程中能夠使患者更為舒適。
本文為研發(fā)生物相容性好、快速止血以及工藝簡(jiǎn)單的海藻酸鈣止血海綿敷料提供了新思路,在醫(yī)用止血海綿方面有良好的應(yīng)用前景。
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Preparation and properties of a chitosan/calcium alginate hemostatic sponge
LUO Shuang1, WU Ying2, LI Huimin1, SU Jing1, WANG Hongbo1
(1.College of Textile Science and Engineering, Jiangnan University, Wuxi 214122, China; 2.Sheng Huadun Protection Technology Co., Ltd., Wuxi 214413, China)
Abstract: In daily life as well as in clinical surgery, the first problem that needs to be solved is how to quickly stop bleeding from wounds. Prolonged exposure of wounds to air can easily lead to infections and loss of bodily fluids, which can impact wound healing and, in severe cases, even cause complications. This can impact wound healing and, in severe cases, even lead to complications. Traditional dressings are still widely used on skin injuries, primarily due to their affordability, simplicity in preparation, and ease of application. However, their role in wound healing is limited by their simple physical coverage, tendency to adhere to wounds and limited capacity to absorb tissue fluid, which restricts their effectiveness in wound healing. Natural polysaccharides are highly advantageous in the direction of preparing new sponge dressings due to their excellent biocompatibility, degradability, widespread availability, and affordability. Sponge dressings made from polysaccharides not only retain the sponge's excellent breathability and fluid absorption capabilities but also possess the inherent advantages of polysaccharides.
Calcium carbonate (CaCO3) is an inorganic material widely found in natural substances such as limestone and coral, which is inexpensive, readily available, safe and non-toxic, and therefore has garnered significant attention in the biomedical industry. To improve the sponge formed by the exogenous gel method of freeze-drying traditional calcium alginate sponges, it is necessary to address issues such as hard texture, lengthy process, and uneven cross-linking. One way to achieve this is by re-crosslinking the sponge through immersion in calcium chloride solution. The thesis uses sodium alginate (SA) and chitosan (CS) as the base materials, CaCO3 as the source of Ca2+ for ionic cross-linking, and regulates the pH value of the solvent to control the cross-linking speed to simultaneously trigger ionic cross-linking and electrostatic interactions, and employs internal gelation to stabilize the sponge's cross-linked structure, so that the sponge dressings which are soft and skin-friendly and able to stop hemostatic quickly are prepared. The main research is as follows:CS and SA were dissolved in pH=4.5 acetic acid-sodium acetate solution, and then CaCO3 suspension was uniformly dispersed in the mixture, which was left to cross-link for 24 h and then frozen at -20℃, and the sponge samples of uniform texture were produced by vacuum freeze-drying. This study explored the formation mechanism, morphological structure, physicochemical properties, blood safety, and hemostatic performance of the sponge. The sponge samples were made by vacuum freeze-drying. The test results showed that the sponge had better performance when the CaCO3 mass fraction was 0.4%, with a liquid absorption rate of (1,234±49.36)%, a coagulation index (BCI) of (13.924±0.963)%, an in vitro degradation rate of (76.708±2.302)%, and a haemolysis rate of less than 5% in all cases. The sponge exhibits excellent liquid absorption capacity, rapid hemostasis, safety, non-toxicity, and in vitro degradability, making it a potential candidate for biological hemostatic materials.
Due to the basic nature of the sponge material, the novel hemostatic sponge exhibits a limitation in terms of poor mechanical properties. In future research, it is anticipated that combining the sponge with traditional dressings could enhance hemostasis and wound healing effects while simultaneously improving mechanical properties. And the intricate porous structure of the sponge dressing also makes it has a great potential for drug loading applications.
Keywords:calcium carbonate; chitosan; sodium alginate; hemostatic sponge; extracorporeal coagulation; liquid
absorption