| 摘要: | 在本研究中，帶負電微脂粒的製備主要是由陰離子型界面活性劑與磷脂質所構成。製備微脂粒所使用的主要材料是氫化大豆磷脂質hydrogenated soybean phosphatidylcholine (HSPC) 和不飽和的卵磷脂質 egg phosphatidylcholine (EPC) ，額外再添加如雙十六碳鏈磷酸鹽 (dicetyl phosphate, DCP) 、硬脂酸 (stearic acid, SA) 與維生素 E (vitamin E, VitE) 等材料。針對混合 HSPC/VitE 、 HSPC/DCP 、 HSPC/SA 與混合 EPC/ DCP 及 EPC/SA 所形成的微脂粒，利用粒徑和界面電位分佈，以及螢光偏極化等特性的分析，探討其物理化學特徵。再者，觀察在 24 ℃ 下，不同比例混合微脂粒物理穩定性及其隨時間的變化。 HSPC 混合 DCP 、 SA 、 VitE 三種添加物的微脂粒系統，物性評估結果以 XvitE = 0.4 或 0.5、XSA = 0.5 與 XDCP = 1等組成的穩定性最好，而在 EPC 系統中則以 XSA = 0.1 與XDCP = 1 最穩定。此外，螢光偏極化分析的結果顯示添加 SA 與 DCP 莫耳比 < 50 mol % 對 HSPC 微脂粒的螢光偏極化值影響不大，但是 VitE 則有增加 HSPC 薄膜流動性的效果。然而，添加 SA 和 DCP 於 EPC微脂粒中會使得EPC脂雙層的流動性降低。
藉由 Langmuir trough 技術，探討純水或乙醇溶液界面上不同比例混合HSPC/VitE 、 HSPC/DCP 、 HSPC/SA 、 EPC/ DCP 與 EPC/SA 單分子層的行為。從等溫線的結果可知HSPC 與 VitE 、 HSPC 與 DCP 、 HSPC 與SA 、EPC 與 DCP 以及 EPC 與 SA 等雙成分系統在純水上或乙醇溶液界面上皆是可以互相混合的 (miscible) 。在 HSPC 與 EPC 系統中添加 DCP 、 SA ，會使單分子層變得較凝縮 (condensed) ，然而，在 HSPC 系統中， VitE 的添加卻會使混合單分子層變得較伸展 (expanded) 。經由過剩面積計算發現這些雙成分系統皆呈現非理想混合單分子層的行為。添加 DCP 會使 HSPC 與 EPC呈現負偏差的過剩面積，但是在 HSPC 單分子層中，隨著SA莫耳比例的增加，過剩面積會由正偏差轉為負偏差。混合HSPC/VitE 單分子層的過剩面積則呈現正偏差。
經由流變儀量測微脂粒-高分子 (hydroxylethyl cellulose, HEC 和 carbopol® 940, C940) 凝膠的黏度、儲存與損失模數等特性。結果顯示微脂粒溶液呈現接近牛頓流體的行為，但微脂粒或純水溶液添加 C940 與 HEC 凝膠皆呈現非牛頓流體特性。在低 HEC 濃度之微脂粒凝膠與純水凝膠呈現損失模數 (G”) > 儲存模數 (G’) ，流體為 liquid-like ，但在高 HEC 濃度之微脂粒凝膠與純水凝膠隨頻率增加則依序出現 G” > G’ (liquid like) 、 G” = G’ 及 G’ > G” (solid-like) 等特徵。然而，在低 C940 濃度之微脂粒凝膠與純水凝膠呈現 G” > G’ ，流體為 liquid-like ，反之高 C940 濃度下之凝膠則呈現 G’ > G” ，此為 solid-like 的特徵。本研究發現不同分散液不會大幅改變凝膠的流變特性，但是不同的高分子增稠劑及濃度卻會主導流體的行為。
Negative liposomes are prepared mainly by anion surfactants and phosphatidylcholines in this study. Hydrogen soybean phosphatidylchloine (HSPC), egg phosphatidylchloine (EPC), and additives such as dicetyl phosphate (DCP) , stearic acid (SA) and vitamin E (VitE) were used herein. Size and zeta potential distributions as well as fluorescence polarization of mixed HSPC/VitE, HSPC/SA, HSPC/DCP, EPC/SA, and EPC/DCP liposomes were measured in order to investigate their physicochemical properties. The physical stability of liposomes changed with time was recorded at 24℃ storage. The results for HSPC mixed with DCP, SA, and VitE showed that XvitE = 0.4 or 0.5, XSA = 0.5, and XDCP = 1 had the best physical stability, and for the EPC system XSA = 0.1, XDCP = 1 did. Analysis of fluorescence polarization HSPC system displayed as SA, DCP increase fluorescence polarization differences between them the polarized value is not great, except the amount added VitE with increasing film mobility have increased. However, to EPC liposomes mixed SA and DCP will EPC bilayer of fluidity reduces.
By using a Langmuir trough technique to investigate behavior of mixed HSPC/VitE, HSPC/SA, HSPC/DCP, EPC/SA, and EPC/DCP monolayers on the water and ethanol solution subphases. The results from isotherms indicated that HSPC and VitE, HSPC and DCP, HSPC and SA, EPC and DCP, and EPC and SA of binary systems are miscible on pure water or ethanol solution. In HSPC and EPC systems, addition of DCP or SA made mixed monolayer become more condensed. However, VitE made HSPC monolayer be more expanded. Through the calculation of excess area, one can find that these binary systems expressed the non-ideal mixed monolayer behavior. Adding of DCP into HSPC and EPC monolayers showed negative deviation of excess area. But excess area changed from positive to negative deviations as increasing mole ratio of SA in HSPC monolayer. The excess area for mixed HSPC/VitE monolayers displayed a positive deviation.
Viscosity, storage modulus and loss modulus properties of liposomes- polymer gels (hydroxylethyl cellulose, HEC, and carbopol® 940, C940) wer measured by means of a rheometer. The results showed that liposomes solution were the Newtonian fluid, but liposomes or water mixed HEC or C940 gel exhibited non-Newtonian fluid characteristic. The low concentration of HEC with liposomes gel or water gel showed loss modulus (G") > storage modulus (G'), fluid is liquid-like. The high concentration of HEC with liposomes gel or water gel showed G" > G' (liquid like), G" = G' and G ' > G" (solid-like) characteristics as increasing the sweeping frequency. However, the low concentration of C940 with liposomes gel or water gel showing G" > G' indicated the fluid is liquid-like. In the contrast, the high concentration of C940 showing G' > G", implied the gel is solid-like. It was found that dispersion category did not obviously change the rheological properties of gel, but the concentration and the category of polymer dominated the behavior of gel. |
