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61.
Solid lipid nanoparticles loaded with bovine serum albumin(BSA) were prepared by a double emulsion method. As the mass fraction of the model drug BSA increased from 0 to 15%, the particle size gradually increased. The physical stability of the nanoparticles was investigated by zeta potential measurement and they were shown to be quite stable. Fluorescence spectroscopy confirmed that the loaded position of BSA was on the interface between the inner aqueous phase and the solid lipid phase. Both Fourier-transf... 相似文献
62.
A new formulation forS(k), the structure factor, has been obtained, treating the square-well potential as a perturbation on the hard-core in the mean
spherical model approximation. The potential parameters have been varied not only to get a satisfactory peak height at the
fitted temperature but also over a wide range of temperatures and densities. The agreement between the computed and experimental
structure factor values shows that the representation of the attractive tail by a square-well potential yields a satisfactory
method in understanding the structure of liquid argon. 相似文献
63.
Solid-supported thin liquid films of lipids, contacting an electrolyte phase, turned out to be a dependable system in the field of bosensors. The investigations of these objects during the past decade reveal some of their intriguing features enabling the application in constructions of receptor part with 'two-dimensional' arrangement. As a model system, complementary to the other artificial analogs of biomembranes, the wetting films of lipids offer certain advantages concerning the compromise between the stability and flexibility of the molecular structures involved in sensing. The basic principles underlaying the techniques of formation, as well as the conditions of the films stability are emphasized in the present consized review. While no limitations are imposed by the way of preparation, the films seem especially profitable in conjunction with methods for electrochemical signal transduction. In this regard some prominent examples are discussed. 相似文献
64.
The leakage of aqueous contents of neutral (dipalmitoylphosphatidylcholine/cholesterol) liposomes as induced by Rz1, a proline-rich lipoprotein, the bacteriophage Rz1 gene product, was studied. Fluorescence enhancement assay with Tb3+/dipicolinic acid and self-quenching assays with carboxyfluorescein and fluorescein isothiocyanaten-dextran were used to monitor the Rz1-induced leakage from neutral liposomes. The results demonstrated that Rz1 caused local membrane destabilization leading to the leakage of the liposome contents. The extent of the leakage was independent of the molecular mass of the liposome-entrapped solutes in the range of 376–4000 Da. The kinetics of Rz1-liposome leakage was very similar to that obtained with detergent Triton X-100 for all the solutes used. The results suggested that Rz1 can act as a detergent; i.e., by interacting with lipids on both sides of the liposome membranes (inducing perturbation in the lipid packing within the bilayer), it facilitates the transfer of encapsulated molecules into the external liposome environment. The importance of this result for Rz1 physiological function is discussed. 相似文献
65.
66.
Medha Rele B. S. Patro S. Adhikari G. P. Kalena S. Chattopadhyay T. Mukherjee 《Journal of Chemical Sciences》2002,114(6):739-747
The free radical scavenging properties and possible antioxidant activity of 1,3-diphenylpropane-1,3-dione (1) are reported.
Pulse radiolysis technique was employed to study the one-electron oxidation of 1 with various radicals viz. CCl3O2
•, N3
• and•OH in homogeneous aqueous solution. All these radicals reacted with 1 under ambient conditions at almost diffusion controlled
rates producing transient species with an absorption maximum around 420 nm that decayed at first order rates. The transient
absorption peak was shifted in the case of CCl3OO• radical reaction with 1 due to change in the polarity of the medium. Formation of a stable product with a broad absorption
band starting from 400 nm and cut off at 230 nm was observed in the oxidation of 1 with•OH and•N3 radicals. In a biological system also, 1 showed significant inhibitory activity against Fe2+-mediatedlipidperoxidation. Based on these observations, a suitable mechanism for the oxidation of 1 has been proposed. 相似文献
67.
Meili Qu Qiying Lv Bing Yang Weide Zhang Jiaqi Zhang Shuzhong Zhan Jianshan Ye 《Electroanalysis》2010,22(4):375-378
Supported bilayer lipid membrane (s‐BLM) containing one‐dimensional compound 1, TCNQ‐based (TCNQ=7,7,8,8‐tetracyanoquinodimethane) organometallic compound {(Cu2(μ‐Cl)(μ‐dppm)2)(μ2‐TCNQ)}∞, was prepared and characterized on the self‐assembled monolayer (SAM) of 1‐octadecylmercaptan (C18H37SH) deposited onto Au electrode. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results showed that the compound 1, dotted inside s‐BLM, can act as mediator for electron transfer across the membrane. Two redox peaks and the charge‐transfer resistance of 400 kΩ were observed for compound 1 inside s‐BLM. The mechanism of the electron transfer across s‐BLM by TCNQ is by electron hopping while TCNQ‐based organometallic compound is by conducting. Further conclusion drawn from this finding is that the TCNQ‐based organometallic compound embedded inside s‐BLM exhibits excellent electron transfer ability than that of free TCNQ. This opens a new path for the development of s‐BLM sensor and/or biosensor by incorporation with TCNQ‐based organometallic compounds. 相似文献
68.
Protegrin‐1 (PG‐1) belongs to the family of antimicrobial peptides. It interacts specifically with the membrane of a pathogen and kills the pathogen by releasing its cellular contents. To fully understand the energetics governing the orientation of PG‐1 in different membrane environments and its effects on the physicochemical properties of the peptide and membrane bilayers, we have performed the potential of mean force (PMF) calculations as a function of its tilt angle at four distinct rotation angles in explicit membranes composed of either DLPC (1,2‐dilauroylphosphatidylcholine) or POPC (1‐palmitoyl‐2‐oleoylphosphatidylcholine) lipid molecules. The resulting PMFs in explicit lipid bilayers were then used to search for the optimal hydrophobic thickness of the EEF1/IMM1 implicit membrane model in which a two‐dimensional PMF in the tilt and rotation space was calculated. The PMFs in explicit membrane systems clearly reveal that the energetically favorable tilt angle is affected by both the membrane hydrophobic thickness and the PG‐1 rotation angle. Local thinning of the membrane around PG‐1 is observed upon PG‐1 tilting. The thinning is caused by both hydrophobic mismatch and arginine‐lipid head group interactions. The two‐dimensional PMF in the implicit membrane is in good accordance with those from the explicit membrane simulations. The ensemble‐averaged Val16 15N and 13CO chemical shifts weighted by the two‐dimensional PMF agree fairly well with the experimental values, suggesting the importance of peptide dynamics in calculating such ensemble properties for direct comparison with experimental observables. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010 相似文献
69.
70.
Nishizuka T Fujita Y Sato Y Nakano A Kakino A Ohshima S Kanda T Yoshimoto R Sawamura T 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2011,87(3):104-113
Lectin-like oxidized LDL receptor-1 (LOX-1) is an endothelial receptor for oxidized LDL (oxLDL) and plays multiple roles in the development of cardiovascular diseases. We screened more than 400 foodstuff extracts for identifying materials that inhibit oxLDL binding to LOX-1. Results showed that 52 extracts inhibited LOX-1 by more than 70% in cell-free assays. Subsequent cell-based assays revealed that a variety of foodstuffs known to be rich in procyanidins such as grape seed extracts and apple polyphenols, potently inhibited oxLDL uptake in Chinese hamster ovary (CHO) cells expressing LOX-1. Indeed, purified procyanidins significantly inhibited oxLDL binding to LOX-1 while other ingredients of apple polyphenols did not. Moreover, chronic administration of oligomeric procyanidins suppressed lipid accumulation in vascular wall in hypertensive rats fed with high fat diet. These results suggest that procyanidins are LOX-1 inhibitors and LOX-1 inhibition might be a possible underlying mechanism of the well-known vascular protective effects of red wine, the French Paradox. 相似文献