壳聚糖纳米微球对牛血清蛋白的包封和缓释效果研究

壳聚糖(chitosan,CS)是甲壳素脱乙酰化的产物,是由葡萄糖结构单元组成的直链多糖。CS作为一种带正电荷的天然多糖,本身具有无毒、无刺激性、无致敏性、无致突变的性质,降解产物为低分子壳寡糖和葡萄糖胺,具有良好的生物相容性和生物降解性[1-2]。CS本身具有的特性,引起了人们的     

Spherical hydrophilic microparticles obtained by the radical copolymerisation of functionalised bovine serum albumin

Unsaturated groups were introduced onto proteins in order to produce macromers that are able to undergo radical polymerisation. The initial protein used was bovine serum albumin (BSA) because it is biodegradable, biocompatible and easily available. Methacrylic groups were introduced onto BSA by reaction with methacrylic anhydride at controlled pH and temperature. The experimental conditions allowed the protein to be kept water-soluble. This water-solubility of the derivatised protein was essential when realising spherical polymeric microparticles via reverse phase suspension copolymerisation with N,N-dimethyacrylamide (DMAA). During the derivatisation, the insertion of the polymerisable groups affects only the sterically-available chemical functions of the native protein. Therefore, chain growth during the copolymerisation process involves only these groups, achieving a polymeric network around a structurally unmodified protein. The polymeric systems show high water affinity, ascribable to the hydrophilic properties of BSA. We have demonstrated that the achievement of the spherical form during the polymerisation depends on two factors: the degree of derivatisation of BSA, and the weight/weight (w/w) ratio of the protein to the comonomer. The beads obtained were characterised by Fourier transform IR spectrophotometry, particle size distribution analysis, and scanning electron microscopy (SEM). The samples investigated showed a remarkable affinity for water and a high swelling capacity. These properties depend upon the degree of derivatisation of BSA and on the percentage of DMAA in the copolymerisation mixture. In this paper we describe the starting materials and the experimental conditions used to prepare protein hydrogels by radical copolymerisation, which are intended for use in pharmaceutical and biomedical applications.     

Patterns of the adsorption of bovine serum albumin on carboxymethyl dextran and carboxymethyl cellulose films

Patterns of the adsorption of bovine serum albumin on carboxymethyl dextran and carboxymethyl cellulose films are studied by means of microcontact printing, atomic force microscopy, and quartz crystal microbalance. It is shown that both the charge of polysaccharide macromolecules and the technique for deposition of their films onto the surface (via adsorption from a solution or covalent cross-linking) are factors that determine the degree of nonspecific adsorption of the protein on such films.     

Effect of adsorption of bovine serum albumin on liposomal membrane characteristics

The effect of adsorption of bovine serum albumin (BSA) on the membrane characteristics of liposomes at pH 7.4 was examined in terms of zeta potential, micropolarity, microfluidity and permeability of liposomal bilayer membranes, where negatively charged L-alpha-dipalmitoylphosphatidylglycerol (DPPG)/L-alpha-dipalmitoylphosphatidylcholine (DPPC), negatively charged dicetylphosphate (DCP)/DPPC and positively charged stearylamine (SA)/DPPC mixed liposomes were used. BSA with negative charges adsorbed on negatively charged DPPG/DPPC mixed liposomes but did not adsorb on negatively charged DCP/DPPC and positively charged SA/DPPC mixed liposomes. Furthermore, the adsorption amount of BSA on the mixed DPPG/DPPC liposomes increased with increasing the mole fraction of DPPG in spite of a possible electrostatic repulsion between BSA and DPPG. Thus, the adsorption of BSA on liposomes was likely to be related to the hydrophobic interaction between BSA and liposomes. The microfluidity of liposomal bilayer membranes near the bilayer center decreased by the adsorption of BSA, while the permeability of liposomal bilayer membranes increased by the adsorption of BSA on liposomes. These results are considered to be due to that the adsorption of BSA brings about a phase separation in liposomes and that a temporary gap is consequently formed in the liposomal bilayer membranes, thereby the permeability of liposomal bilayer membranes increases by the adsorption of BSA.     

Molecular weight effects on gelation and rheological properties of konjac glucomannan–xanthan mixtures

Fractions of konjac glucomannan (KGM) with various viscosity‐average molecular weights (M_v) ranging from 4.00 × 10⁵ to 2.50 × 10⁶ were prepared by hydrolysis degradation in hydrochloride acid/ethanol. Effect of M_v of KGM on the critical gelation temperature (T_gel) determined by Winter–Chambon criterion and the elasticity of KGM/xanthan mixed gels, a kind of binary gel formed by synergistic gelation, were investigated by dynamic viscoelastic measurements. It was shown that the value of T_gel of the gel was shifted to a higher temperature and the gel strength was enhanced when M_v of KGM was increased. The critical M_v (1.91 × 10⁶) was observed, above which the T_gel and elasticity of the mixed gels showed no or slight increase. It was suggested that T_gel and elasticity of KGM/xanthan mixed gels mainly depend on the structure of junction zones driven by the strong interaction between KGM and xanthan, which was gradually improved with increasing M_v of KGM. It was found that the critical strain and yield stress of the mixed gels increased monotonically with the increasing M_v of KGM. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 313–321, 2010     

3-[二(羧甲基)氨甲基]-1, 2-二羟基蒽醌与蛋白质作用的研究

在pH4.1的缓冲溶液中,研究3-[二(羧甲基)氨甲基]-1,2-二羟基蒽醌(AFB)与牛血清蛋白(BSA)结合反应,相互生成的紫色的配合物。采用UV光谱法,测得此配合物的最大吸收峰值为510nm,与试剂本身相比较红移90nm。表观摩尔吸光系数ε=1.2474×10^4mol^-^1.cm^-^1.L,最大结合数n=7,表观结合常数K~c=3.85×10^6。研究发现,AFB与BSA之间主要是以分子之间的静电引力结合,认为该反应符合Scatchard模型。离子强度对结合反应有显著的影响。     

Evaluation of retention and release processes of two antibiotics from the biocompatible core-shell microparticles

By dropwise addition of a chitosan solution into different non-solvent, such as: 1 N and 2 N NaOH as well as 1 N NaOH: C₂H₅OH mixture (2:1, v/v) at temperature of 25 °C and 50 °C under stirring, the spherical pure chitosan microparticles were performed. As solvents for chitosan was used 0.1 N acetic acid or 0.1 N HCl. The immersion of the pure chitosan microparticles in hyaluronan solution led to complex microparticles, namely chitosan microparticles covered by a hyaluronan layer. For all the microparticles performed the behaviours in the retention process of two antibiotics: chloramphenicol succinate sodium salt and cefotaxime sodium salt were analyzed. Also, the study shows the release behaviour of cefotaxime sodium salt by the microparticles loaded with this drug. Among the microparticles performed a type of complex microparticles can be considered a suitable drug delivery system for cefotaxime. These microparticles were performed by dropwise addition of chitosan solution in 0.1 N acetic acid into the 1 N NaOH: C₂H₅OH (2:1, v/v) non-solvent at 20 °C for 3 h, followed by their washing up to alkalinity loss and the immersion in hyaluronan solution of 10 g/L concentration for 24 h.     

Self-assembly of human serum albumin (HSA) and L-alpha-dimyristoylphosphatidic acid (DMPA) microcapsules for controlled drug release

Human serum albumin (HSA) and L-alpha-dimyristoylphosphatidic acid (DMPA) were applied as a pair to encapsulate ibuprofen microcrystals by means of a technique based on the layer-by-layer (LbL) assembly of oppositely charged species, for the purpose of controlling drug release. The successful adsorption of HSA and DMPA multilayers onto ibuprofen crystals was confirmed by optical microscopy. The drug release process, in a solution of pH 7.4, was monitored by optical microscopy and UV spectroscopy. The results revealed that the rate of release of ibuprofen from HSA/DMPA microcapsules decreased as the capsule wall thickness and drug crystal size increased, indicating that the permeability of the microcapsules can be controlled by simply varying the number of HSA/DMPA deposition cycles.     

牛血清白蛋白和溶菌酶为双模板蛋白质的表面印迹聚合物的制备及吸附性能

采用反应条件温和的原子转移自由基聚合法(ATRP),以N-异丙基丙烯酰胺(NIPAAm)和丙烯酰胺(AAm)为功能单体,以N-(3-二甲氨基丙基)甲基丙烯酰胺(DMAPMA)为辅助功能单体,制备了以牛血清白蛋白(BSA)和溶菌酶(Lyz)为双模板蛋白质的表面印迹聚合物(Bi-MIP)。对印迹过程中辅助功能单体的量进行了考察,结果表明,在单一蛋白质溶液和混合蛋白质溶液中,当DMAPMA为20 μL时,制备的Bi-MIP对模板蛋白质BSA和Lyz有较好的吸附容量与选择性。通过静态吸附实验考察了Bi-MIP的吸附性能,并结合Langmuir吸附模型得到聚合物对模板蛋白质BSA和Lyz的最大吸附容量分别为10.2 mg/g和19.2 mg/g。且该印迹聚合物在实际样品中对模板蛋白质也表现出较强的吸附能力和较高的选择性。该方法将为复杂生物样品中同时对双/多种目标蛋白质的识别提供一种新的途径。     

Preparation of microparticles composed of cinnamoyl gelatin and cinnamoyl alginate by spray-drying method and effect of UV irradiation and pH value on their release property

Microparticles composed of cinnamoyl gelatin (CinGel) and cinnamoyl alginate (CinAlg) were prepared as a UV irradiation- and pH-responsive carrier by a spray-drying method. CinGel and CinAlg were prepared by a condensation reaction. Using a colorimetric method, the gelatin to CA mass ratio and the alginate to CA mass ratio were calculated to be 1:0.04 and 1:0.02, respectively. The complexation of CinGel and CinAlg in aqueous solution took place when the medium was acidic (e.g., pH 4.0) and the maximum complexation was obtained when the CinGel/CinAlg mass ratio was 7:3. On SEM photographs, some spray-dried CinGel/CinAlg particles were spherical and others were irregularly shaped, and the diameter was a few to tens of micrometers. The release degrees of amaranth loaded in UV-treated microparticles were lower than those of the dye loaded in UV-untreated ones, possibly because of the photo cross-linkage of CinGel and CinAlg. Regardless of whether the microparticles were UV-treated, the release degree at pH 4.0 was significantly lower than the release degree at pH 6.0 and pH 8.0, possibly because of complexation of CinGel and CinAlg under the acidic condition.     

Encapsulation of L-dopa and catechol in bovine serum albumin nanocarrier using desolvation method and their in vitro release studies

In the current study, the interaction between L-dopa and bovine serum albumin (BSA) as well as catechol and BSA is investigated separately. In order to achieve the optimum values for encapsulated efficiency (EE), the content of crosslinker/BSA, organic/aqueous phase, drug/BSA, stirring rate, and pH were closely studied taking the advantage of Taguchi method. Particle characterization was carried out using transmission electron microscopy and dynamic light scattering techniques. The most appropriate catechol and L-dopa nanoparticles in the size range of 100 nm and 65 nm, respectively, and at optimized conditions of drug/BSA = 0.1, pH = 7.4, crosslinker/BSA = 0.084, organic/aqueous phase = 4 and stirring rate 400 rpm were obtained. The most favorable EE (encapsulation efficiency) and LC (loading capacity) for L-dopa and catechol was estimated to be 88.1% and 83.6%, respectively, and the calculated LC% was achieved 93.4% and 89.7% for L-dopa and catechol, respectively. The chromatographic analyses results were also found to be in a good agreement with the obtained data for the calculated EE% and LC% values. in vitro release of loaded drugs from nanoparticles in phosphate-buffered saline (pH = 7.4, incubated at 37 ± 0.5°C under stirring rate of 100 rpm) showed the release of 78% catechol and 89% L-dopa during 480 min and 510 min, respectively.     

肼黄与牛血清白蛋白相互作用的光谱研究

本文用荧光光谱法和紫外-可见吸收光谱法研究了肼黄与牛血清白蛋白(BSA)结合反应的光谱行为,发现肼黄因对BSA有较强的荧光猝灭作用,且肼黄的紫外吸收光谱和BSA的荧光发射光谱有一定程度的重叠,据此得出了其结合反应的结合常数、结合位点数和基本热力学参数等,并研究了二者的相互作用机理。     

Encapsulation and/or release behavior of bovine serum albumin within and from polylactide-grafted dextran microspheres

Polylactide (PLA)-grafted dextran (Dex-graft-PLA) of various contents of sugar units was synthesized by anionic polymerization of L-lactide (L-LA) using the alkoxide of partially trimethylsilylated dextran (TMSDex) and subsequently removing the trimethylsilyl (TMS) groups. The copolymer showed different solubility from L-LA homopolymer with increasing the content of sugar units. We prepared bovine serum albumin (BSA)-loaded microspheres (MS)s according to a water-in-oil-in-water emulsion-solvent evaporation/extraction method using methylene chloride/DMSO as an organic cosolvent. MSs prepared from Dex-graft-PLA [MS(Dex-graft-PLA)s] exhibited higher loading efficiency of BSA than MSs prepared from PLLA [MS(PLLA)s]. The in vitro release rate of BSA from MS(Dex-graft-PLA) was faster than that from MS(PLLA). BSA released from MS(Dex-graft-PLA) maintained the secondary structure of native BSA to a great extent, compared with BSA released from MS(PLLA).     

Effects of lysozyme and bovine serum albumin on membrane characteristics of dipalmitoylphosphatidylglycerol liposomes

The effects of adsorption of two kinds of proteins on the membrane characteristics of liposomes were examined at pH 7.4 in terms of adsorption amounts of proteins on liposomes, penetrations of proteins into liposomal bilayer membranes, phase transition temperature, microviscosity and permeability of liposomal bilayer membranes, using positively charged lysozyme (LSZ) and negatively charged bovine serum albumin (BSA) as proteins and negatively charged L-alpha-dipalmitoylphosphatidylglycerol (DPPG) liposomes. The saturated adsorption amount of LSZ was 720 g per mol of liposomal DPPG, while that of BSA was 44 g per mol of liposomal DPPG. The penetration of LSZ into DPPG lipid membranes was greater than that of BSA. The microviscosity in the hydrophobic region of liposomal bilayer membranes increased due to adsorption (penetration) of LSZ or BSA, while the permeability of liposomal bilayer membranes increased. The gel-liquid crystalline phase transition temperature of liposomal bilayer membranes was not affected by adsorption of LSZ or BSA, while the DSC peak area (heat of phase transition) decreased with increasing adsorption amount of LSZ or BSA. It is suggested that boundary DPPG makes no contribution to the phase transition and that boundary DPPG and bulk DPPG are in the phase-separated state, thereby increasing the permeability of liposomal bilayer membranes through adsorption of LSZ or BSA. A possible schematic model for the adsorption of LSZ or BSA on DPPG liposomes was proposed.     

羧甲基壳聚糖制备中的溶剂影响及精制方法研究

研究了有机溶剂中两步法制取羧甲基壳聚糖的反应过程.采用有机溶剂溶胀、氢氧化钠碱化、氯乙酸改性、乙醇溶析等步骤制备了高取代度羧甲基壳聚糖.考察了碱用量、氯乙酸用量和有机溶剂类型三个因素对羧甲基壳聚糖取代度的影响.通过比较二甲基亚砜、异丙醇、丙酮和乙醇四种有机溶剂中壳聚糖羧甲基化取代度变化规律,分析了羧甲基化的机理.实验结...     

三价铁对灯盏花素与牛血清白蛋白相互作用的影响

运用荧光光谱、紫外吸收光谱探讨了Fe3+对灯盏花素(BR)与牛血清白蛋白(BSA)相互作用的影响;从Fe3+与BSA的静电作用、配位结合以及Fe3+与BR的配位作用等方面分析了影响BR与BSA相互作用的因素.结果表明,Fe3+不改变BSA与BR的作用机制,但使得二者结合的猝灭常数、结合常数及结合位点数减小.     

Human serum albumin in electrospun PCL fibers: structure,release, and exposure on fiber surface

Human serum albumin (HSA) introduced to the fibers produced by electrospinning from HSA and polycaprolactone (PCL) solutions in hexafluoroisopropanol has been studied in terms of its structure, release from the fibers, stability of interaction with basic polymer, accessibility for protease attack, and cellular receptors, as well as dependence of the studied parameters on the protein concentration in fibers. A limited part of the protein leaves the fibers right after soaking with water, whereas the remaining protein stays tightly bound to fibers for a long time because protein nanoparticles are tightly integrated with PCL, as shown by small‐angle X‐ray scattering. As has been demonstrated, the proteins leave the fibers in complexes with PCL. X‐ray photoelectron spectroscopy demonstrates that the protein concentration on the fiber surface is higher than the concentration in electrospinning solution. The surface‐exposed protein is recognized by cell receptors and is partially hydrolyzed by proteinase K. The data on pulse protein release, presence of PCL in the protein released from matrixes, overrepresentation of the protein on the fiber surface, and tight interaction of protein with PCL may be useful for rational design of electrospun scaffolds intended for drug delivery and tissue engineering. Copyright © 2016 John Wiley & Sons, Ltd.     

孔雀石绿与牛血清白蛋白作用的光谱研究

应用荧光及紫外光谱法研究了孔雀石绿(MG)与牛血清白蛋白(BSA)相互作用的光谱特性。测定了16℃、26℃、36℃三个温度下的结合常数KA(7.066×103、4.638×103、1.338×103)和结合位点数n(1.2、1.1、1.0)。结果表明:MG对BSA内源荧光的猝灭机理主要为静态猝灭;MG主要以范德华力与BSA相互作用;同步荧光技术研究了MG对BSA构象的影响,表明BSA的荧光主要源于色氨酸残基,MG对BSA的构象有影响;利用F ster偶极-偶极非辐射能量转移理论,计算了三个温度下MG与BSA的作用距离(r16℃=3.30,r26℃=3.314,r36℃=3.58nm),表明MG对BSA的荧光猝灭中存在能量转移。     

Hydrophilic polymer drug from a derivative of salicylic acid: synthesis, controlled release studies and biological behavior

Hydrophilic polymeric drugs bearing "Triflusal" (4-trifluoromethylsalicylic acid), a drug widely used as antithrombogenic agent (Disgren), have been prepared by free radical copolymerization of methacryloyloxyethyl [2-(acetyloxy)-4-(trifluoromethyl)] benzoate (HTRF) and N,N'-dimethylacrylamide (DMA). The reactivity ratios of both monomers have been determined by 1H NMR spectra by applying non-linear least square treatments to the copolymerization equation (terminal model), and the kinetic parameters obtained indicated that the microstructure of copolymer chains is homogeneous, with a random distribution of the active HTRF units along the copolymer chains. That means that for the copolymer system THDMA22 used in this work, HTRF units are mainly isolated in relatively long DMA sequences. Therefore, in this structure the intramolecular interactions between adjacent HTRF units are negligible. Release of Triflusal from THDMA22 has been studied in vitro using buffered solutions at pH = 2, 7.4 and 10 and 37 degrees C. The system showed an interesting pseudo-zero order release profile at pH = 7.4 during several months. It has been also evaluated the pharmacological activity and the behavior of the system in contact with biological media. In this sense, we have carried out some in vitro studies about the antiaggregant properties and biocompatibility of THDMA22. Results demonstrate that this copolymer inhibits platelet aggregation in its macromolecular form and presents a good biocompatibility with Human Osteoblastic Cells (HOS).     

金丝桃苷与牛血清白蛋白相互作用的研究

采用荧光共振能量转移法研究了金丝桃苷与牛血清白蛋白的相互作用.金丝桃苷对牛血清白蛋白(BSA)的荧光猝灭类型是静态猝灭,25℃时的结合位点数为0.5451.并依据F(o)ster非辐射能量转移理论,研究了给体(牛血清白蛋白)--受体(金丝桃苷)间的结合距离R.和能量转移效率E分别为2.04nm和0.66.同时,采用同步...