H/J-聚集体虾青素/牛血清白蛋白纳米复合物的制备与表征

Preparation and characterization of H/J aggregates of astaxanthin/bovine serum albumin nanoparticles

以牛血清白蛋白(bovine serum albumin,BSA)作为载体包载虾青素(astaxanthin,AST),制备稳定可控的H/J-聚集体虾青素/牛血清白蛋白纳米粒(H/J-aggregates astaxanthin/bovine serum albumin nanoparticles,H/J-ABNs),改善虾青素不稳定且水分散性差的特性。精准控制乙醇-水溶液比例制备H/J聚集体虾青素,在25℃、200 r/min、20 min的磁力搅拌条件下制备H/J-ABNs,并进行表征分析。研究结果表明:H-ABNs的最佳制备条件为将体积分数20%的虾青素乙醇溶液逐滴滴加至0.05 mg/mL的BSA溶液中磁力搅拌20 min;J-ABNs的最佳制备条件为以体积分数35%的虾青素乙醇溶液为溶质,同条件制备;H-ABNs和J-ABNs粒径分别为(146±24)nm和(266±8)nm,电位分别为(-9.69±0.89)mV和(-6.16±0.45)mV,结合率分别为61.1%和66.47%,负载率分别为3.46%和9.72%;UV-vis显示H-ABNs的最大吸收光谱在378 nm处,而J-ABNs在520 nm和560 nm附近表现为肩峰;红外光谱分析显示H/J-ABNs中蛋白质的二级结构发生改变,BSA发生荧光猝灭,最大发射波长发生蓝移;荧光光谱检测显示H/J-ABNs的光谱吸收大大削弱,并发生蓝移,表明虾青素与BSA结合后引起了氨基酸残基周围微环境疏水性的增加。结合各项理化表征和透射电镜分析,证实AST成功以聚集体形式被包裹在BSA建立的疏水微区中,表明牛血清白蛋白有潜力作为聚集体虾青素的纳米递送。

Bovine serum albumin(BSA)was used as a carrier to encapsulate astaxanthin(AST)to prepare stable and controllable H/J-aggregates of astaxanthin/bovine serum albumin nanoparticles(H/J-ABNs)to improve the unstable and poorly water-dispersible properties of astaxanthin.In this study,stable and controlled H/J-aggregates of astaxanthin/bovine serum albumin nanoparticles(H/J-ABNs)were prepared using bovine serum albumin as a carrier at the condition of magnetic stirring speed 200 r/min for 20 min at 25℃,then the nanoparticles were characterized and preliminary binding mechanisms were explored.The results showed that the optimal conditions for the preparation of ABNs:H-ABNs were prepared by adding 20% volume fraction astaxanthin ethanol solution dropwise to 0.05 mg/mL BSA solution;other conditions were kept constant,and J-ABNs were prepared by adding 35% volume fraction astaxanthin ethanol solution to BSA solution;the physical and chemical properties showed that the particle sizes of H-ABNs and J-ABNs were(146±24)nm and(266±8)nm,zeta potentials were(-9.69±0.89)mV and(-6.16±0.45)mV,binding rates were 25.74% and 66.47%,and drug loading rates were 3.77% and 9.72%,respectively;the UV-vis spectra showed that the maximum absorption spectrum of H-ABNs was at 378 nm,while J-ABNs exhibited shoulder peaks near 520 nm and 560 nm;infrared spectroscopy analysis showed that the infrared characteristic absorption peaks of both BSA and astaxanthin in the aggregated astaxanthin nanoparticles were greatly weakened relative to the single protein and astaxanthin powder,indicating that the BSA conformation had changed in the presence of astaxanthin;fluorescence spectroscopy detection showed that the spectral absorption of H/J-ABNs was greatly weakened and blue-shifted,indicating that astaxanthin binding to BSA induced an increase in the hydrophobic microenvironment around the amino acid residues.Combined with various physicochemical characterizations and transmission electron microscopy analyses,it was confirmed that AST was successfully encapsulated in the hydrophobic microregion established by BSA as an aggregate,suggesting that bovine serum albumin has the potential to serve as a nano-delivery of aggregated astaxanthin.