Incorporation Of Bovine Serum Albumin Research Articles

Incorporation of bovine serum albumin into biomimetic coatings on titanium with high loading efficacy and its release behavior

Bovine serum albumin (BSA) was employed as a model protein to study its loading efficiency into a calcium phosphate (CaP) coating on titanium substrates. It is found that the protein loading efficiency can be adjusted by varying the specific configurations of the coating system such as simulated body fluid (SBF) volume, solution height and container selection for the SBF. A BSA loading efficiency as high as 90% was achieved when the ratio of the substrate surface area to modified SBF (m-SBF) volume was as high as 0.072. The release of BSA from the biomimetic coatings was also investigated in vitro. A sustained release was achieved although a large quantity of BSA was still trapped in the coating after 15 days of immersion in a phosphate buffer solution. A much faster release rate would be expected when the coating is implanted in vivo due to the active involvement of osteoclast cells and enzymes.

Formulation of the adenylate cyclase toxin of Bordetella pertussis as protein-coated microcrystals

Adenylate cyclase toxin (CyaA) is an important virulence factor of Bordetella pertussis, the causative agent of whooping cough, and, in its detoxified form, a potential component of acellular pertussis vaccines. This study reports the application of a novel technology, formulation of CyaA as protein-coated microcrystals (PCMC), to improve the performance of CyaA as a vaccine component. CyaA is normally stored in a high urea concentration to prevent aggregation and to maintain stability of the protein. The aim of the work was to stabilise CyaA on a crystalline support to create a dry powder that could be reconstituted in aqueous buffer, free of urea. CyaA, formulated as PCMC with microcrystals of dl-valine, retained full adenylate cyclase (AC) and cell invasive (cytotoxic) activities after solubilistion in urea buffer. After storage as a dry powder at 37 °C for 2 weeks, the AC activity recovered from the CyaA-PCMC was only marginally reduced when solubilised in urea buffer. No AC activity was detected after attempts to solubilise CyaA-PCMC in aqueous buffer alone, in the absence of urea. Inclusion of various ionic, non-ionic or zwitterionic detergents in the aqueous buffer had little effect on recovery of CyaA activities. However, preparation of PCMC with CyaA plus calmodulin (CaM) or bovine serum albumin (BSA) or with both proteins allowed restoration of AC and cytotoxic activities of CyaA upon solubilisation in aqueous buffer. Incorporation of BSA and CaM with CyaA allowed essentially full recovery of AC activity but lower recovery of cytotoxicity. CyaA-CaM-BSA-PCMC, after reconstitution in aqueous buffer, induced a strong serum IgG response to CyaA when injected subcutaneously into mice.

Comparison of simple aromatic amines for electrosynthesis of permselective polymers in biosensor fabrication

A range of simple aromatic amines were used to modify Pt microcylinders with insulating electrosynthesised polymers generated amperometrically in the presence or absence of a typical globular protein, bovine serum albumin (BSA), at neutral pH. Sensitivity to a typical interference species, ascorbic acid (AA), and the most common electrochemical signal molecule for oxidase enzymes, H2O2, was used to compare the suitability of the resulting polymer–protein modified electrodes for biosensor applications. Pt modified with poly(aminobenzene), PANI, gave the lowest sensitivity to AA (∼3000 times lower than bare Pt); incorporation of BSA into the polymer during synthesis had a detrimental effect on its AA-rejecting capability. The H2O2 sensitivity of the PANI-based electrodes was poor (∼7 times lower) compared to bare Pt. The behaviour of poly(1,2-diaminobenzene), PoPD, was different in many respects: its AA-blocking ability was enhanced 3-fold by the presence of BSA and its H2O2 sensitivity was similar to bare Pt. EQCM data recorded in PBS indicated that PANI films electrosynthesised at pH 7.4 were two orders of magnitude thicker than for PoPD. These differences may be due, at least in part, to the ‘ladder’ structure with phenazine rings proposed for PoPD, since they were not duplicated by other mono-substituted derivatives of aniline, such as 2-methylaniline or 1,3-diaminobenzene.

Incorporation of bovine serum albumin in calcium phosphate coating on titanium.

Calcium phosphate (Ca-P) and bovine serum albumin (BSA) were coprecipitated as a coating on commercially pure titanium (cpTi) with a high protein loading (15 wt %) by employing a recently developed wet-chemistry technique. It was observed that the incorporation of BSA significantly modified the morphology, composition, and crystallinity of the Ca-P coating. The Ca-P coating without BSA is a mixture of hydroxyapatite (HA) and octacalcium phosphate (OCP) with sharp-edged thin OCP crystal plates on the top layer, whereas only an HA phase was detected in the Ca-P/BSA coating. The crystal plates in the latter had a more rounded appearance. The Ca-P/BSA coatings were immersed respectively in neutral (pH 7.4) and acidic (starting pH 4.0) phosphate-buffered saline (PBS) at 37 degrees C over a 14-day period. No protein release was detected in the neutral PBS during the immersion; however, a continuous release of BSA was measured in the acidic PBS, subsequently leading to the formation of a very dense and well-adherent composite coating of BSA and Ca-P on cpTi. The present study provides the possibility to achieve a long-term effective release of biologically active proteins from a Ca-P-coated metallic implant.

Increase of Liposome Stability by Incorporation of Bovine Serum Albumin

AbstractThe incorporation of the bovine serum albumin in the liposomal membrane to prevent leakage of the entrapped contents was studied. Adsorption of bovine serum albumin was found on the liposomes. After the adsorption of bovine serum albumin, by the addition of glutaraldehyde, the serum albumin molecules cross-linked to themselves and stiffened the membrane structure of the liposomes. It was found that the particle size of the liposomes increased after the treatment of glutaraldehyde. However, there was no significant change in particle size for the liposomes with the stirring effect. Adriamycin, methotrexate, carboxyfluorescein and mitoxantrone were entrapped into this liposome system. The loading efficiency demonstrated a similar value for the liposomes with and without the treatment of glutaraldehyde. However, for the entrapment of adriamycin, there showed an increase in loading efficiency with the effect of glutaraldehyde. For the leakage examination, a decrease of the release rate of the adriamyc...

Low temperature incorporation of bovine serum albumin into a bead formed macroporous hydrophilic polymer matrix with potential for sustained release.

A process of freeze-thaw polymerization involving the low temperature photopolymerization of a mixed solution of monomers and bovine serum albumin around frozen ice crystals has been used to generate a bead formed macroporous hydrophilic matrix with potential for sustained release. Beads over the size range 100-3000 microns were fabricated with surface and internal pores of between 0.7-2.6 microns whose diameter could be controlled by manipulation of the monomers to solvent ratio. Increasing both the proportion of monomers in the monomer solution and the percentage of BSA incorporated reduced the EWC of beads. The BSA release profile was characterized by an initial burst followed by a lower but sustained release lasting up to 1 month. The total cumulative release of BSA and the proportion of the incorporated BSA load subsequently released were both reduced in physiological saline compared with distilled water but enhanced by freeze drying, mild agitation and incubation at 37 degrees C.

Mitochondrial preparations from the fruit of the apple—II. : Oxidative phosphorylation

Mitochondria prepared from the peel and pulp of apple fruits gave good oxidative phosphorylation with acids of the Kiebs' cycle. They also exhibited the phenomenon of “respiratory control”. In senescent fruit the power of the mitochondria prepared therefrom to fix inorganic phosphate decreases and respiratory control is also much decreased. There are indications that loss of phosphorylation and respiratory control by mitochondria prepared from senescent fruits may be overcome to some extent by the incorporation of bovine serum albumin in the extraction medium.