Bovine Serum Albumin Microspheres Research Articles

Preparation, physicochemical, and antibacterial properties of bovine serum albumin microspheres loaded with sodium nitrite

In this study, NaNO2-embedded bovine serum albumin microspheres (BSAMs) were prepared by oil-in-water emulsification method, which was covalently cross-linked with transglutaminase (TGase). Moreover, the physicochemical properties and antibacterial effect of BSAMs on Escherichia coli, Staphylococcus aureus, Pseudomonas, and beef and pork jerky were also analyzed. The particle size of BSAMs was about 0.5–2.5 μm observed by scanning electron microscopy. Almost all NaNO2 was encapsulated inside BSAMs, and there was no NaNO2 attaching on the surface of BSAMs. The encapsulation rate of NaNO2 first increased from 0 to 20 U/g TGase and then decreased from 20 to 40 U/g TGase; likewise, the release of NO first increased with the increase of TGase (0–20 U/g) and it decreased when the TGase concentration was 30 and 40 U/g. Based the results of minimal inhibitory concentration and minimal bactericidal concentration, E. coli and Pseudomonas were more sensitive to BSAMs than S. aureus. In addition, the slow release of NO from BSAMs could significantly inhibit the growth of bacteria on the surface of beef and pork jerky in a weak acidic environment compared with NaNO2 used directly, so as to achieve long-term antibacterial effect and prolong the shelf life of meat products.

Sonochemically Prepared BSA Microspheres as Adsorbents for the Removal of Organic Pollutants from Water.

This work investigates, for the first time, the application of sonochemically prepared bovine serum albumin (BSA) microspheres (BSAMS) as adsorbents of industrial organic pollutant dyes, such as rhodamine B (RhB), rhodamine 6G (Rh6G), and methylene blue (MB). These dyes also serve as model compounds for other organic pollutants such as bisphenol A and 2-nitrophenol. Adsorption kinetics of the dyes by the BSAMS was studied using pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models. It was found that RhB follows PFO, with an adsorption capacity, qe,cal, of 7.9 mg/g, which was closer to the experimental adsorption capacity of qe,exp. of 7.6 mg/g. However, MB and Rh6G were controlled by PSO kinetics, with a qe,cal of 5.6 mg/g for MB and 6.6 mg/g for Rh6G, closer to the experimental adsorption capacity of 5.7 and 6.4 mg/g, respectively. The intraparticle diffusion (ID) model applied to the three dyes indicated multi-linearity with ID as the rate-limiting step in the adsorption process. Furthermore, the adsorption equilibria for each of the organic pollutants were studied through various isotherm models such as Langmuir, Freundlich, Temkin, and Halsey, which indicated physical interaction between the BSAMS and the dye pollutants, thus suggesting the applicability of the BSAMS as pollutant adsorbent materials. It was found that the BSAMS can effectively remove RhB, MB, and Rh6G from wastewater with efficiencies of 95.5, 83.3, and 97.9%, respectively.

Biocompatible Polymer and Protein Microspheres with Inverse Photonic Glass Structure for Random Micro‐Biolasers

The miniaturization of random lasers to the micrometer scale is challenging but fundamental for the integration of lasers with photonic integrated circuits and biological tissues. Herein, it is demonstrated that random lasers with a diameter from 30 to 160 μm can be achieved by using a simple emulsion process and selective chemical etching. These tiny random laser sources are made of either dye‐doped polyvinyl alcohol (PVA) or bovine serum albumin (BSA) and they are in the form of microporous spheres with monodisperse pores of 1.28 μm in diameter. Clear lasing action is observed when the microporous spheres are optically excited with powers larger than the lasing threshold, which is 154 μJ mm−2 for a 75 μm diameter PVA microporous sphere. The lasing wavelength redshifts 10 nm when the PVA microsphere diameter increases from 34 to 160 μm. For BSA microspheres, the lasing threshold is around 55 μJ mm−2 for a 70 μm diameter sphere and 104 μJ mm−2 for a 35 μm diameter sphere. The simple fabrication process reported allows for detail studies of morphology and size, important for fundamental studies of light–matter interaction in complex media, and applications in photonic integrated circuits, photonic barcoding, and optical biosensing.

Development and validation of an HPLC method for determination of rofecoxib in bovine serum albumin microspheres.

A simple and reliable HPLC method was developed and validated for determination of rofecoxib in bovine serum albumin microsphere. The analyses were performed on a C18 column (150 x 4.6 mm, 5 μm particle size) at room temperature with UV detection at 272 nm. The mobile phase was composed of acetonitrile-0.1% o-phosphoric acid solution in water (1:1, v/v) mixture, and flow rate was set to 1 mL/min. The method was validated according to the international guidelines with respect to stability, linearity range, limit of quantitation and detection, precision, accuracy, specificity, and robustness. The detection and quantification limit of the method were 1.0 μg/mL and 2.5 μg/mL, respectively. The method was linear in the range of 2.5–25 μg/mL with excellent determination coefficients (R2 >0.99). Intra-day and inter-day precision (<1.76% RSD) and accuracy (<0.55 % Bias) values of the method also fulfilled the required limits. It was concluded that the developed method was accurate, sensitive, precise, and reproducible according to the evaluation of the validation parameters. The applicability of the method was confirmed for in vitro quantification of rofecoxib in bovine serum albumin microspheres.

Entrapment and release kinetics study of dyes from BSA microspheres forming a matrix and a reservoir system

Two kinds of Bovine Serum Albumin (BSA)-loaded microspheres were prepared in water-organic bilayer systems using ultrasonic irradiation. The first method included an aqueous solution of BSA and water-soluble dye together, mixed with dodecane, that upon sonication formed a matrix system where the dye is concentrated in the protein shell. The other system included an aqueous solution of BSA mixed with octanol-soluble dye that, upon sonication, formed a reservoir system in which the dye filled the inner volume of the microspheres. Each of these microspheres was prepared with two different dyes and their leaching profiles into pure solvents were studied using UV-vis spectrometry. Fast leaching was observed at the beginning for both systems, which levelled-off after a certain time. For the matrix system, an equilibrium state was obtained after 100-200 hours, whereas for the reservoir system, leaching occurred much faster, within 1-3 hours. Such systems can serve as models for drug delivery agents.

Integrated Experimental and Modeling Study of Enzymatic Degradation Using Novel Autofluorescent BSA Microspheres.

Autofluorescent bovine serum albumin (BSA) hydrogel microspheres were prepared through the spray-drying of glutaraldehyde cross-linked BSA nanoparticles and then used for a proteinase K based degradation study in an aqueous solution. Experimental results and empirical models are presented to characterize the kinetics of BSA hydrogel microsphere degradation, as well as the accompanying release of synthesized fluorophore. The BSA gel degradation dynamics is primarily controlled by the concentration of proteinase K within the Tris buffer. The coupling of swelling dynamics and the transient distributions of fluorophore are traced by confocal microscopy. Models are developed based on the linear theory of elastic deformation coupled to enzyme and fluorophore transport. This study represents a fundamental investigation of the degradation and release kinetics of protein-based materials, which can potentially be applied for the dynamic and photostable tracking of relevant in vivo systems.

A New Approach to Chiral Enrichment by Exposure of Racemates of Amino Acids to Sonochemically‐Prepared BSA Microspheres

AbstractThis preliminary study describes a one‐step sonochemical formation of Bovine Serum Albumin (BSA) microspheres and their chiral interaction with several amino acids. Partial separation between enantiomers of various amino acids was accomplished by the interaction of these microspheres with solutions of racemic amino acids. The highest rate of enantiomeric enrichment was attained for D,L‐cysteine, where 59% enantiomeric excess (ee) of the L‐cysteine was measured. This indicates the preferrential interaction of the BSA microspheres with the D‐enantiomer of cystein. No chiral activity was observed for unsonicated BSA molecules. All other D,L‐amino acids that were examined provided enrichment of the D‐enantiomer albeit in lower ee values. D,L‐cysteine interacted with the BSA microspheres leading to L‐enantioselective enrichment up to 59 % ee at room tempertaure and 72% at 5 °C. Chiral enrichment was also carried out succesfully with other protein microspheres such as Avidin microspheres. In this case up to 41 % ee was acheived on interaction with DL‐phenylalanine. Our simple and facile method opens a new window for enantiomeric separation of racemic compounds.

Mussel-inspired nano-building block assemblies for mimicking extracellular matrix microenvironments with multiple functions

The assembly of nano-building blocks is an effective way to produce artificial extracellular matrix microenvironments with hierarchical micro/nano structures. However, it is hard to assemble different types of nano-building blocks, to form composite coatings with multiple functions, by traditional layer-by-layer (LbL) self-assembly methods. Inspired by the mussel adhesion mechanism, we developed polydopamine (PDA)-decorated bovine serum albumin microspheres (BSA-MS) and nano-hydroxyapatite (nano-HA), and assembled them to form bioactive coatings with micro/nano structures encapsulating bone morphogenetic protein-2 (BMP-2). First, PDA-decorated nano-HA (nano-pHA) was obtained by oxidative polymerization of dopamine on nano-HA. Second, BMP-2-encapsulated BSA microspheres were prepared through desolvation, and then were also decorated by PDA (pBSA-MS). Finally, the nano-pHA and pBSA-MS were assembled using the adhesive properties of PDA. Bone marrow stromal cell cultures and in vivo implantation, showed that the pHA/pBSA (BMP-2) coatings can promote cell adhesion, proliferation, and benefited for osteoinductivity. PDA decoration was also applied to assemble various functional nanoparticles, such as nano-HA, polystyrene, and Fe3O4 nanoparticles. In summary, this study provides a novel strategy for the assembly of biofunctional nano-building blocks, which surpasses traditional LbL self-assembly of polyelectrolytes, and can find broad applications in bioactive agents delivery or multi-functional coatings.

Protein Microspheres with Unique Green and Red Autofluorescence for Noninvasively Tracking and Modeling Their in Vivo Biodegradation.

Bovine serum albumin (BSA) microspheres were prepared through a facile and low-cost route including a high-speed dispersion of BSA in cross-linking solution followed by spray drying. Interestingly the as-prepared BSA microspheres possess unique blue-green, green, green-yellow, and red fluorescence when excited by specific wavelengths of laser or LED light. The studies of UV-visible reflectance spectra and fluorescence emission spectra indicated that four classes of fluorescent compounds are presumably formed during the fabrication processes. The formation and the potential contributors for the unique green and red autofluorescence were also discussed and proposed though the exact structures of the fluorophores formed remain elusive due to the complexity of the protein system. The effect of spray-drying conditions on the morphology of spray-dried samples was investigated and optimized. FTIR was further employed to characterize the formation of the functional groups in the as-prepared autofluorescent microspheres. Good in vitro and in vivo biocompatibility was demonstrated by the cytotoxicity test on the A549 cancer cells and tissue histological analysis, respectively. The autofluorescent BSA microspheres themselves were then applied as a novel tracer for convenient tracking/modeling of the biodegradation of autofluorescent BSA microspheres injected into mouse model based on noninvasive, time-dependent fluorescence images of the mice, in which experimental data are in good agreement with the proposed mathematical model. All these studies indicate that the as-developed protein microspheres exhibiting good biocompatibility, biodegradability, and unique autofluorescence, can significantly broaden biomedical applications of fluorescent protein particles.

High azithromycin concentration in lungs by way of bovine serum albumin microspheres as targeted drug delivery: lung targeting efficiency in albino mice.

BackgroundFollowing administration, the antibiotic travels freely through the body and also accumulates in other parts apart from the infection site. High dosage and repeated ingestion of antibiotics in the treatment of pneumonia leads to undesirable effects and inappropriate disposition of the drug. By way of targeted lung delivery, this study was intended to eliminate inappropriate azithromycin disposition and to achieve higher azithromycin concentration to treat deeper airway infections.MethodsThe Azithromycin Albumin Microspheres (AAM) was prepared by emulsion polymerization technique. The optimized AAM was subjected to in vitro release study, release kinetics, XRD and stability studies. Further, in vivo pharmacokinetics and tissue distribution of azithromycin released from AAM and azithromycin solution in albino mice was investigated to prove suitability of moving forward the next steps in the clinic.ResultsThe mean particle size of the optimized AAM was 10.02 μm, an optimal size to get deposited in the lungs by mechanical entrapment. The maximum encapsulation efficiency of 82.3 % was observed in this study. The release kinetic was significant and best fitted for Korsmeyer-Peppas model (R2 = 0.9962, n = 0.41). The XRD and stability study showed favorable results. Azithromycin concentration in mice lungs (40.62 μg g−1, 30 min) of AAM was appreciably higher than other tissues and plasma. In comparison with control, azithromycin concentration in lungs was 30.15 μg g−1 after 30 min. The azithromycin AUC (929.94 μg h mL−1) and intake rate (re) (8.88) for lung were higher and statistically significant in AAM group. Compared with spleen and liver, the targeting efficacy (te) in mice lung increased by a factor of 40.15 and ~14.10 respectively. Subsequently by a factor of 8.94, the ratio of peak concentration (Ce) in lung was higher in AAM treated mice. The AAM lung tissue histopathology did not show any degenerative changes.ConclusionsHigh azithromycin concentration in albino mice lung was adequately achieved by targeted drug delivery.

Abstract 4411: Oral drug formulations containing microspheres

Abstract Oral anticancer drug formulations are considerably favorable not only for patient adherence, but also for ease of administration. The main objective of the present research was to develop extended-release capsule formulations containing doxorubicin hydrochloride-encapsulated albumin microspheres. Albumin-based polymeric microspheres were evaluated as a potential platform technology for providing extended-release of oral dosage formulations. Bovine serum albumin microspheres were prepared by spray drying and characterized for their physicochemical properties. Scanning electron microscopy (SEM) was used to analyze the size, surface morphology, and size distribution of the drug-loaded microspheres. Zeta potential measurements were carried out to assess the surface properties and stability of the microsphere formulations. Dissolution studies were conducted to analyze the release profiles of the microspheres and capsule-containing microsphere drug formulations. SEM analysis indicated that microspheres were less than 2-μm in size, which is considered to be optimal for uptake by the enterocytes. The average Zeta potential measurements were approximately -30 mV. Additionally, the data showed that microspheres, which contained 1% BSA and 0.1% glutaraldehyde, provided a drug release profile that is desirable for cancer therapy. Both microsphere and capsule-encapsulating microsphere formulations were shown to provide extended-release of the drug over 36 hours. Thus, capsules containing biodegradable microspheres show potential for effective delivery of oral drug formulations. Citation Format: Duc P. Do, Alexander Kar. Oral drug formulations containing microspheres. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4411. doi:10.1158/1538-7445.AM2015-4411

MicroglassificationTM: A Novel Technique for Protein Dehydration

The dehydration of biologics is commonly employed to achieve solid-dose formulation and enhanced stability during long-term preservation. We have developed a novel process, Microglassification™, which can rapidly and controllably dehydrate protein solutions into solid amorphous microspheres at room temperature. Single bovine serum albumin (BSA) microdroplets were suspended in pentanol or decanol using a micropipette, and the dynamic changes in droplet dissolution were observed in real-time and correlated to protein's water of hydration, medium's water activity, and microsphere protein concentration. Microglassification™ was also carried out at bulk scale, and changes in BSA secondary structure were analyzed by Fourier transform infrared spectroscopy and fluorescence spectroscopy; multimer formation was detected by native gel electrophoresis. BSA concentration in the microsphere increased with solvent exposure time and decreasing water activity. Image analysis at single particle and bulk scale showed the formation of solid BSA microspheres with a maximum protein concentration of 1147 ± 32 mg/mL. The native BSA samples were dehydrated to approximately 450 waters per BSA, which is well below monolayer coverage of 1282 waters per BSA. The secondary structure of Microglassified™ BSA reverted to native-like conformation upon rehydration with only minor irreversible aggregation (2.7%). Results of the study establish the efficacy of the Microglassification™ for the successful dehydration of biologics.

Layer-by-layer multienzyme assembly for highly sensitive electrochemical immunoassay based on tyramine signal amplification strategy

A new sandwich-type electrochemical immunosensor based on nanosilver-doped bovine serum albumin microspheres (Ag@BSA) with a high ratio of horseradish peroxidase (HRP) and detection antibody was developed for quantitative monitoring of biomarkers (carcinoembryonic antigen, CEA, used in this case) by coupling enzymatic biocatalytic precipitation with tyramine signal amplification strategy on capture antibody-modified glassy carbon electrode. Two immunosensing protocols (with and without tyramine signal amplification) were also investigated for the detection of CEA and improved analytical features were acquired with tyramine signal amplification strategy. With the labeling method, the performance and factors influencing the electrochemical immunoassay were studied and evaluated in detail. Under the optimal conditions, the electrochemical immunosensor exhibited a wide dynamic range of 0.005–80ngmL−1 toward CEA standards with a low detection limit of 5.0pgmL−1. Intra- and inter-assay coefficients of variation were below 11%. No significant differences at the 0.05 significance level were encountered in the analysis of 6 clinical serum specimens and 6 spiked new-born cattle serum samples between the electrochemical immunoassay and the commercialized electrochemiluminescent immunoassay method for the detection of CEA.

Antibody modified Bovine Serum Albumin microspheres for targeted delivery of anticancer agent Gemcitabine

Inhibition of the EGFR signaling pathway is one of the attractive therapeutic targets for pancreatic cancer as recent studies demonstrated that EGFR is over‐expressed in pancreatic cancer. In this article we have demonstrated the design of targeted drug delivery system containing Bovine Serum Albumin (BSA) microspheres as delivery vehicle, gemcitabine as anticancer drug and anti‐EGFR (epidermal growth factor receptor) monoclonal antibody as targeting agent. The conjugated BSA microspheres were characterized by several physico‐chemical techniques such as scanning electron microscope, optical microscopy, fluorescent microscopy etc. Administration of these BSA microspheres containing gemcitabine and anti‐EGFR (BSA‐Gem‐EGFR) shows significant inhibition of pancreatic cancer cells (AsPC1) compared to the cells treated with only BSA microspheres, BSA with gemcitabine (BSA‐Gem), and free gemcitabine. This strategy could be used as a generalized approach for the treatment of pancreatic cancer along with other cancers which overexpress EGFR on cell surface. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Enhanced oral bioavailability of calcium using bovine serum albumin microspheres

Low oral bioavailability of calcium leads to impairment of calcium homeostasis particularly during the high requirement phases of human growth. The objective of the current study was to prepare microspheres of calcium using bovine serum albumin and assess its viability to enhance the oral bioavailability. Microspheres of calcium were prepared by emulsion chemical cross linking method, characterized, evaluated for in vitro release and in vivo absorption. The prepared microspheres were found to be spherical in shape with smooth surface. High entrapment efficiency (>50%), desired particle size (<10 µm), high zeta potential values (−30.91 ± 3.06 to −34.65 ± 1.01 mV) and low polydispersity indices (0.61 ± 0.04 to 0.88 ± 0.05) were recorded in the prepared microspheres. In vitro release profile suggests that <10% of calcium was discharged in the gastric media (in 30 min) from the microspheres prepared using higher drug/polymer ratio (1:1, formulation F4). The pharmacokinetic data obtained in Sprague–Dawley rats showed that the rate and extent of calcium absorption was significantly enhanced following the administration of microspheres. The serum calcium level profiles indicate that the Cmax and AUC0–α were significantly higher (p < 0.001) when calcium was administered from microspheres when compared to control. Rapid absorption of calcium was also observed from microspheres and may be attributed to a greater uptake into intestinal Peyer’s patches. Given the excellent results in the in vivo studies, it can be concluded that calcium loaded bovine serum albumin microspheres could be an effective and promising approach for the oral therapy of calcium. Indeed, this approach can be an alternative to parenteral therapy in acute hypocalcaemia as well.

Encapsulation of RNA Molecules in BSA Microspheres and Internalization into Trypanosoma Brucei Parasites and Human U2OS Cancer Cells

AbstractRNA was encapsulated in bovine serum albumin (BSA) microspheres using a one‐step sonochemical process from an water–oil solvent biphasic system. Confocal microcoscopy and fluorescence‐activated cell sorting indicate that a CY3‐RNA (RNA labeled with red fluorescent indocarbocyanine Cy3 dye) sphere is encapsulated in the BSA outer sphere. The diameter of the sphere depends on the number of nucleotides of the RNA, ranging from 0.63 to 2.74 μm. Total RNA (t‐RNA) was used as a prototype for the future small interfering RNA (siRNA) delivery. A very broad size distribution characterizes the RNA spheres and therefore, among the loaded BSA spheres, there were sufficiently small spheres to be successfully introduced into trypanosoma brucei parasites and human osteosarcoma U2OS cancer cells.

Novel approach for preparing nontoxic stealth microspheres for drug delivery

Normal.dotm 0 0 1 124 709 Uni 5 1 870 12.0 0 false 18 pt 18 pt 0 0 false false false Polyethylene glycol 2000 (PEG) entrapped, bovine serum albumin (BSA) microspheres were prepared and optimized. These microspheres were then analyzed to understand the stealth effect to the microspheres imparted by incorporated polyethylene glycol (PEG). Microsphere preparations (formulations) were studied for particle size, zeta potential, free BSA content, and in-vitro uptake by human micro-vascular endothelial cells (HMECs). The results demonstrate, a formulation containing 37.5 % PEG (w/w) exhibits an acceptable particle size of &lt;5 µm, good suspendibility with zeta potential of -35 mV, and confers some degree of stealth property to the microspheres. These non-toxic, biodegradable and long circulating microspheres have the potential to be used for extended intravenous (IV) drug delivery. Statistical analysis done by ANOVA and results with p&lt;0.05 were considered significant.

Albumin/Gentamicin Microspheres Produced by Supercritical Assisted Atomization: Optimization of Size, Drug Loading and Release

In this work, the supercritical assisted atomization (SAA) is proposed, for the first time, not only as a micronization technology but also as a thermal coagulation process for the production of bovine serum albumin (BSA) microspheres charged with Gentamicin sulfate (GS). Particularly, different water solutions of BSA/GS were processed by SAA to produce protein microspheres with different size and antibiotic content. SAA precipitation temperature was selected in the range 100-130 °C to generate protein coagulation and to recover micronized BSA in form of hydrophobic aggregates; GS loading was varied between 10% and 50% (w/w) with an encapsulation efficiency which often reached 100%. In all cases, spherical and noncoalescing particles were successfully produced with a mean particle size of 2 µm and with a standard deviation of about ±1 µm. The microspheres also showed a good stability and constant water content after 60 days of storage. The release profiles of the entrapped drug were monitored using Franz cells to evaluate the possible application of the produced microspheres in wound dressing formulations. Particularly, the microspheres with a BSA/GS ratio of 4:1 after the first burst effect (of 40% of GS loaded) were able to release the GS continuously over 10 days.

A novel approach to preparing magnetic protein microspheres with core-shell structure

Magnetic protein microspheres with core-shell structure were prepared through a novel approach based on the sonochemical method and the emulsion solvent evaporation method. The microspheres are composed of the oleic acid and undecylenic acid modified Fe 3O 4 cores and coated with globular bovine serum albumin (BSA). Under an optimized condition, up to 57.8 wt% of approximately 10 nm superparamagnetic Fe 3O 4 nanoparticles could be uniformly encapsulated into the BSA microspheres with the diameter of approximately 160 nm and the high saturation magnetization of 38.5 emu/g, besides of the abundant functional groups. The possible formation mechanism of magnetic microspheres was discussed in detail.

Albumin microspheres for oral delivery of iron

Bovine serum albumin (BSA) microspheres of ferric pyrophosphate (FPP) intended for passive targeting to the Peyer’s patches has been proposed for oral iron supplementation. Microspheres prepared by emulsification chemical cross linking method were characterized for surface topography, entrapment efficiency, particle size, particle charge and in vitro drug release. Microspheres of batch C with FPP to BSA ratio of 1:5 were found to be most suitable for targeting as they exhibited high entrapment (83.88 ± 4.31), high monodispersity (span = 1.24 ± 0.01), and least particle size (dvm = 4.40 ± 0.01). In addition the amount of iron retained in these microspheres despite exposure to simulated gastrointestinal conditions for 5 h was found to be 83.72 ± 4.22%, the highest in the three batches. The in vivo serum iron profiles in normal rats following oral administration displayed a reduced Tmax (2 h), elevated Cmax (106.06 ± 12.18 μg/dL) and increased AUC 0–16 h (647.44 ± 52.33 μg.h/dL) for these microspheres which significantly differed (P <0.05) from FPP solution indicating a higher iron repletion potential of the BSA microspheres.