Release Behavior Of Bovine Serum Albumin Research Articles

Preparation and Properties of Sodium Alginate/Gelatin Hydrogel-Microspheres

Calcium alginate gel microspheres exhibiting pH response release characteristics were prepared, and utilizing Bovine serum albumin (BSA) to evaluate drug release performance. Hydrogels composed of gelatin (GL) and sodium alginate oxide (NALO), with varying ratios (7:3; 4:1; 3:2) were prepared by controlling their composition. Scanning electron microscopy (SEM) and a microplate reader (ELIASA) were used to characterize the microspheres’ microstructure and in vitro BSA release behavior, respectively. The results demonstrated that, under acidic conditions, the BSA release was slower than in neutral conditions. The hydrogels’ physical and chemical properties were analyzed using optical microscopy, Fourier transform infrared spectroscopy (FTIR), swelling experiments and mechanical testing of the hydrogels and microsphere loaded hydrogels. The results showed that a GL to NALO ratio of 7:3 increased the swelling degree, while a 4:1 ratio optimized the mechanical characteristics. The study concluded that the microsphere-loaded hydrogels exhibited significant potential for human drug delivery applications.

Gelatin/alginate-based microspheres with sphere-in-capsule structure for spatiotemporal manipulative drug release in gastrointestinal tract

Microsphere with sphere-in-capsule structure is a multi-drugs delivery system to achieve the purpose of combination therapy. In this paper, we have prepared gelatin/alginate-based microspheres with sphere-in-capsule structure by a relatively fast, simple, and easily large-scale industrialized emulsification method for spatiotemporal manipulative drug release in gastrointestinal tract. Calcium alginate microspheres encapsulated with bovine serum albumin (BSA) were first prepared as inner microspheres, and then inner microspheres and ranitidine hydrochloride (RH) were co-encapsulated by gelatin microspheres to form double-layer microspheres with sphere-in-capsule structure. The size and distribution of microspheres can be easily controlled by emulsifying conditions. The microspheres with sphere-in-capsule structure displayed desirable encapsulation efficiency of BSA (61.52 %) and RH (56.07 %). The in vitro simulated drug release showed the spatiotemporal release feature of microspheres with sphere-in-capsule structure. In the specific simulated fluid, the release behavior and cumulative release of RH (sustainedly released 95 % in simulated gastric fluid) and BSA (rapidly released 73 % in simulated intestinal fluid) were different. The drug release mechanisms were analyzed to determine RH and BSA's release behavior. Overall, the microspheres with sphere-in-capsule structure have the potential application of spatiotemporal manipulative drug delivery in the gastrointestinal tract.

Magnetic dual-responsive semi-IPN nanogels based on chitosan/PNVCL and study on BSA release behavior.

Magnetic thermoresponsive nanogels present a promising new approach for targeted drug delivery. In the present study, bovine serum albumin (BSA) loaded thermo-responsive magnetic semi-IPN nanogels (MTRSI-NGs) were developed. At first poly(N-vinyl caprolactam) (PNVCL) was synthesized by free radical polymerization and then MTRSI-NGs were prepared by crosslinking chitosan in presence of chitosan and Fe3O4. The formation of MTRSI-NGs has been confirmed by FTIR, and the average molecular weight of PNVCL was determined by GPC analysis. Rheological and turbidimetry analysis were used to determine lower critical solution temperature (LCST) of PNVCL and magnetic thermo-responsive nanogels (MTRSI-NGs) around 32 and 37°C, respectively. FE-SEM analysis showed particle size at less than 20nm in the dried state. Dynamic light scattering determined particle size at about 30nm in a swelling state. The analysis of release behavior showed that the BSA release ratio at 40°C was faster than 25°C. The pH release behavior was evaluated at pH 5.5 and 7.4 and showed that the drug release rate at pH 5.5 was more rapid than pH 7.4. The results show MTRSI-NGs are applicable to protein targeted delivery by thermosensitive targeted drug delivery systems.

A comparison study on the release kinetics and mechanism of bovine serum albumin and nanoencapsulated albumin from hydrogel networks

An in situ-forming biodegradable hydrogel network has been developed to achieve extended release of protein drugs. Hyaluronic acids (HA) were selected as the scaffolding materials, and modified to afford thiolated HA (HASH) and methacrylated HA (HAME). Under near physiological conditions, a mixture of HASH and HAME achieved efficient sol-gel transition within 10 min at 37 °C. A systematic study was performed to characterize the morphology, rheological properties, swelling, degradation, and biocompatibility of the obtained hydrogel networks. Next, bovine serum albumin (BSA) and its nanocapsules were entrapped in the hydrogel network. Standard in vitro release studies and mathematic modeling were performed to gain insights into the release kinetics and mechanisms of protein drugs from the hydrogel network. For the hydrogel-nanocapsule hybrid system, a mathematical model combining the release processes from nanocapsules and hydrogel networks has been proposed to describe the release behavior of BSA from nanocapsules entrapped in the hydrogel network.

Bioreducible amino acid-derived polymeric nanoparticles for delivery of functional proteins

We report the preparation of protein encapsulated amino acid derived redox-responsive nanoparticles (NPs) as effective nanocarriers for intracellular delivery of proteins. More specifically, acryloyl derivatives of lysine, ornithine, cystine and cystamine, were employed as monomers and disulfide crosslinkers for non-covalent encapsulation of model protein bovine serum albumin (BSA) and were interfacially crosslinked via free radical polymerization to form redox-responsive protein NPs. Notably, prepared NPs exhibited high protein loading content between 37 and 45%, averaged ∼400 nm in hydrodynamic size and possessed a mean surface charge of -15 mV. Furthermore, blank polymeric NPs displayed exceptional cytocompatibility with cell viability exceeding 92% at concentrations as high as 4 mg/mL, while redox-responsive protein NPs displayed glutathione (GSH)-dependent BSA release behavior in vitro. Additionally, cellular uptake studies confirmed that protein NPs entered MDA-MA-231 cells predominantly via the endocytic pathway. Upon cellular internalization, redox-responsive NPs delivered protein into cytosol of cells within 60 min demonstrating intrinsic endosomolytic characteristics and efficient protein release under cytoplasmic high GSH conditions. Most importantly, insulin analog-loaded NPs significantly increased glucose consumption in HepG2 cultures confirming protein stability and retention of protein function. Cumulatively, our approach presents a simple yet effective strategy for intracellular delivery of biologically active proteins for various biomedical applications.

Chitosan based hydrogel assisted spongelike calcium phosphate mineralization for in-vitro BSA release

New chitosan-g- poly (3-sulfopropyl methacrylate), CHI-g-P(SPMA), hydrogel was prepared by free radical polymerization process and investigated as a template for biomimetic spongelike calcium phosphate mineralization in a solution mimicking physiological condition. Infrared spectroscopy, scanning electron microscopy, X-ray diffraction and transmission electron microscopy confirmed the predominant formation of rod-like hydroxyapatite. The swelling behavior of the nanocomposite was evaluated at different pHs and different saline concentrations. Bovine serum albumin (BSA), as a model protein drug, was loaded in the CHI-g-P(SPMA)/calcium phosphate hybrid. The BSA release behavior was investigated and the results suggested CHI-g-P(SPMA)/calcium phosphate hybrid as controlled release carrier. These results suggest that next generation of polysaccharides based hybrid materials could be interesting for biomedical applications.

Intestine-targeted delivery potency of the O-carboxymethyl chitosan–gum Arabic coacervate: Effects of coacervation acidity and possible mechanism

The potential of the glutaraldehyde-crosslinked O-carboxymethyl chitosan (O-CMC)–gum Arabic (GA) coacervate as an intestine-targeted delivery system for hydrophobic compounds was concerned. OCMC–GA coacervates and emulsified bovine serum albumin (BSA)-loaded microcapsules were prepared in pH3.0, 4.5, and 6.0 and their swelling behaviors as well as BSA release profiles in simulated gastrointestinal fluids were measured. All the coacervates showed higher swelling ratios in the simulated gastric solution than in the simulated intestine and colon solutions and the values increased as the coacervation pH increased from 3.0 to 6.0, but a reversed trend was observed for the BSA release profile. SEM, TEM, and CLSM analysis revealed that the coacervation acidity influenced the swelling and BSA release behavior by changing the matrix density and O-CMC content of the coacervates. It was concluded that the O-CMC–GA coacervate could be used to deliver hydrophobic compounds to the intestine and its delivery performance could be tailored by selecting appropriate coacervation acidity and crosslinking degree.

Preparation and properties of redox responsive modified hyaluronic acid hydrogels for drug release

A series of oxidized hyaluronic acid (oxi‐HA)/3,3′‐dithiobis (propionohydrazide) (DTP) redox responsive hydrogels by Schiff base reaction under physiological conditions were designed and prepared. The influence of the concentration of oxi‐HA and DTP on rheological properties, equilibrium swelling ratio, and degradation rate were investigated. All oxi‐HA/DTP hydrogels exhibited good rheological properties, high equilibrium swelling ratio, low degradation rate, and sustainable drug release properties, and the comprehensive performance of oxi‐HA5/DTP6 hydrogel was better than that of others. The redox responsiveness was evaluated by means of degradation and in vitro bovine serum albumin release behavior investigation with the stimulus of different concentration of dithiothreitol as reducing agent. The intelligent hydrogels could be potentially applied in the fields of drug delivery system, tissue engineering, or cell scaffold materials. Copyright © 2017 John Wiley & Sons, Ltd.

Genipin-crosslinked O-carboxymethyl chitosan-gum Arabic coacervate as a pH-sensitive delivery system and microstructure characterization.

The possibility of genipin-crosslinked O-carboxymethyl chitosan-gum Arabic coacervate as a pH-sensitive delivery vehicle was investigated. O-carboxymethyl chitosan-gum Arabic coacervates separated in pH 3.0, 4.5, and 6.0 were crosslinked by genipin for different durations and the crosslinked products were subjected to crosslinking degree, swelling behavior, bovine serum albumin release profile, and microstructure characterization. Genipin-crosslinking greatly improved the stability of the coacervates against the simulated gastric solution and created certain pH-sensitivity. The coacervates displayed higher swelling ratios in the simulated gastric solution than in the simulated intestine and colon solutions; meanwhile, the coacervates prepared in pH 4.5 and 6.0 swelled more severely than the complex separated in pH 3.0. Nevertheless, the bovine serum albumin release in the simulated gastric solution from the microcapsules prepared in pH 6.0 was much lower than those prepared in pH 4.5 and 3.0, whose cumulative release percentages in the three simulated solutions were 17.14%, 55.23%, and 79.79%, respectively, in crosslinking duration 2 h. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analysis revealed that genipin-crosslinking improved the regularity and compactness of coacervate structure, whereas confocal laser scanning microscopy observation indicated that O-carboxymethyl chitosan content was possibly the major reason for the different swelling and bovine serum albumin release behavior of the coacervates. It was concluded that the genipin-crosslinked O-carboxymethyl chitosan-gum Arabic coacervate was a potential intestine-targeted delivery system and its delivery performance could be tailored by varying the crosslinking degree and coacervation acidity.

Protein encapsulated core–shell structured particles prepared by coaxial electrospraying: Investigation on material and processing variables

Biodegradable polymeric particles have been extensively investigated for controlled drug delivery of various therapeutic agents. ‘Coaxial’ electrospraying was successfully employed in this study, to fabricate core–shell PLGA particles containing bovine serum albumin (BSA) as the model protein, and the results were also compared to particles prepared by ‘emulsion’ electrospraying. Two different molecular weights of PLGA were employed to encapsulate the protein. Solution properties and processing parameters were found to influence the morphology of the core–shell particles. Depending on the type of solvent used to dissolve the polymer as well as the polymer concentration and molecular weight, the mean diameter of the particles varied between 3.0 to 5.5μm. Fluorescence microscopic analysis of the electrosprayed particles using FITC-conjugated BSA demonstrated the core–shell structure of the developed particles. The encapsulation efficiency and release behavior of BSA was influenced by shell:core feeding ratio, protein concentration, and the electrospraying method. The encapsulation efficiency of BSA within the core–shell particles of high and low molecular weight PLGA was found 15.7% and 25.1% higher than the emulsion electrosprayed particles, respectively. Moreover, the total amount of BSA released from low molecular weight PLGA particles was significantly higher than high molecular weight PLGA particles within 43 days of release studies, with negligible effect on encapsulation efficiency. The technique of coaxial electrospraying has high potential for encapsulation of susceptible protein-based therapeutic agents such as growth factors for multiple drug delivery applications.

Preparation of fiber-microsphere scaffolds for loading bioactive substances in gradient amounts

Gradient scaffolds are needed for interface tissue regeneration. In this study, a technique combining electrospinning and electrospraying was developed for preparing poly(L-lactide-co-glycolide) (PLGA) fiber-microsphere scaffolds for loading bioactive substances in gradient amounts. The gradient fiber-microsphere scaffolds contain two sheets of electrospun membranes and a sheet of microspheres loaded with bioactive substances in gradient amounts between the electrospun membranes. The morphologies of the gradient scaffolds were characterized and bovine serum albumin (BSA) was loaded as a model bioactive substance. The amount of BSA-loaded microspheres decreased gradually along the length of the gradient scaffold. The addition of poly (ethylene glycol) significantly improved the hydrophilicity of the gradient scaffold and the release behavior of BSA with respect to the gradient became apparent, with differences in the release amounts along the length of the gradient scaffold being observed. The biocompatibility of the gradient scaffold was verified using MC3T3-E1 pre-osteoblastic cells. The study demonstrated that the combination of electrospinning and electrospraying was a feasible method for the preparation of gradient scaffolds for potential applications in interface tissue engineering.

Effect of Degree of Branching on Properties of Photosensitive Nanoparticles as Drug-Delivery Carriers

Hyperbranched copolymers with different degrees of branching (DBs), poly(3,4-dihydroxycinnamic acid)-co-poly(4-hydroxycinnamic acid) (PCA), were prepared by polycondensation. Amphiphilic PCA–DTT copolymers were prepared by grafting dithiothreitiol (DTT) into PCA by the Michael addition. PCA–DTT nanoparticles were self-assembled by additional water into a DMSO solution of PCA–DTT. The diameter and photoresponsivity of the PCA–DTT nanoparticles were influenced by the DB, and they increased with increasing the DB. Bovine serum albumin (BSA) as a model protein was successfully encapsulated into the PCA–DTT nanoparticles, and the release behavior of BSA was affected by the DB in PBS. These biodegradable and photoresponsive nanoparticles would be useful as functional carriers for drug delivery systems.

Preparation and characterization of a prolonged and sustained drug delivery system: Linear polyacrylamide in poly(N‐isopropylacrylamide)/clay hydrogels

AbstractIn this contribution, a novel smart drug delivery system based on poly(N‐isopropylacrylamide) (PNIPAAm), clay, and linear polyacrylamide (PAAm) was developed for prolonged and sustained controlled drug release. Various amounts linear PAAm were incorporated into PNIPAAm/clay hydrogels. Resulting hydrogels were characterized by scanning electron microscopy, differential scanning calorimetry, and compression measurements to investigate the morphological, thermal, and mechanical properties. The swelling ratio and response kinetics on heating or cooling were also investigated to understand the smart properties. Finally, bovine serum albumin (BSA), used as the model drug, was loaded into the hydrogels to examine and compare the effects of controlled release at different temperatures (20°C and 37°C). The result indicated that all the PNIPAAm/clay/linear PAAm gels showed good smart property with a higher swelling ratio and more complicated deswelling behavior. Although the compression properties of the resulting hydrogels decreased by incorporating the linear PAAm into the network of PNIPAAm/clay, they still showed high compression stress and excellent reversibility. BSA release behavior at 20°C and 37°C revealed that a prolonged release of BSA with the auto‐adjustable function to external temperature changes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Adsorption and Release Behavior of BSA and FN on Nanostructural Ti Surface

The titanium dioxide(TiO2) nanotube arrays with 100 nm diameters on titanium were fabricated by anodic oxidation.The adsorption behaviors of bovine serum albumin(BSA) and fibronectin(FN) onto the nanotube arrays were investigated,and then the protein releases were examined in vitro.Fourier transform infrared spectroscope and Fluorescence microscope were used to qualitative analysis for TiO2 nanotube arrays surfaces after protein adsorption.Adsorbance of protein was detected with the method of Coomassie brilliant blue G-250.The results showed that TiO2 nanotube arrays could obviously improve the adsorption,and the adsorption percentage of FN on samples was larger than that of BSA.The release experiment results suggested that the release behaviors of BSA and FN on the nanotube arrays involved the bust release and the gradual release,and the release mechanism was consistent with Fickian diffusion.

Thermosensitive soy protein/poly(n‐isopropylacrylamide) interpenetrating polymer network hydrogels for drug controlled release

AbstractA series of the thermosensitive interpenetrating polymer network hydrogels composed of soy protein and poly(N‐isopropylacrylamide) were successfully prepared. The structure and properties were systematically characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and differential scanning calorimetry. It was found that the hydrogels had good miscibility and high porosity, and the volume phase transition temperatures of the hydrogels were around 32°C. The release behavior and the release mechanism of a model protein, bovine serum albumin (BSA), were also investigated in detail. The results indicated that the release behavior of BSA had strong temperature dependence and the release percentage of BSA could be controlled by modulating the amount of soy protein or crosslinking agent. The analysis of the release mechanism revealed that the Fickian diffusion controlled release was dominant under the experimental conditions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.

Controlled release of BSA by microsphere-incorporated PLGA scaffolds under cyclic loading

Localized delivery of bioactive molecules from porous biodegradable scaffolds is very important in advanced tissue engineering strategies, and it is necessary to study the delivery under dynamic loading which mimics the in vivo biomechanical environments. In this study, bovine serum albumin (BSA), a model of bioactive proteins, was incorporated into porous poly(l-lactide-co-glycolide) (PLGA) scaffolds by seeding BSA-loaded microspheres onto the scaffold pore wall, where the microspheres of poly(ethylene glycol)-b-poly(l-lactide) (PELA) were prepared by double emulsion technique. The in vitro release behavior of BSA from the scaffold under dynamic cyclic loading was studied in comparison with that under a static condition as well as from PELA microspheres. It was observed that the microsphere-incorporated scaffold prolonged BSA release with respect to the microspheres. The cyclic loading accelerated the release of BSA from the scaffold and the cumulative release on day 10 reached 85% of the totally encapsulated BSA. The delivery under a dynamic condition would be an initial study of in vivo localized delivery of growth factors.

Preparation of oxidized sodium alginate-graft-poly((2-dimethylamino) ethyl methacrylate) gel beads and in vitro controlled release behavior of BSA

Graft copolymerization of amino group-terminated poly((2-dimethylamino) ethyl methacrylate) (PDMAEMA-NH 2) onto oxidized sodium alginate (OSA) was reacted without using a catalyst. The structure of the graft was investigated by Fourier transform infrared (FT-IR) spectroscopy. The OSA-g-PDMAEMA gel beads were prepared by dropping the aqueous solution of the graft copolymer into CaCl 2 aqueous solution. The effects of pH and ionic strength on the swelling behaviors of the gel beads were studied. The results indicate that the gel beads have pH and ionic strength sensitivity. Bovine serum albumin (BSA) was entrapped in the beads and the in vitro drug release profiles were established in buffer solution with pH 1.8 (HCl), pH 7.4 (KH 2PO 4–NaOH), and 0.9% (w/v) NaCl at 37 °C. The results showed that the oral delivery of proteins can be controlled by adjusting the graft percentage ( G, %), pH and ionic strength. According to this study, the OSA-g-PDMAEMA gel beads could be suitable for the oral delivery of proteins.

Fabrication and properties of core‐shell structure P(LLA‐CL) nanofibers by coaxial electrospinning

AbstractIn this article, core‐shell structure nanofibers were fabricated by coaxial electrospinning with biodegradable copolymer Poly(L‐Lactic‐ε‐Caprolactone) [P(LLA‐CL) 50 : 50] as shell and bovine serum albumin (BSA) as core. Morphology and microstructure of the nanofibers were characterized by scanning electron microscopy and transmission electron microscopy. The mechanical properties were investigated by stress‐strain tests. In vitro degradation rates of the nanofibrous membranes were determined by measuring their weight loss when immersed in phosphate‐buffered saline (pH 7.4) for a maximum of 14 days. Release behavior of BSA was measured by an ultraviolet‐visible spectroscopy, and the results demonstrated that BSA could release from P(LLA‐CL) nanofibers in a steady manner. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Modulation of protein release from biodegradable core–shell structured fibers prepared by coaxial electrospinning

Biodegradable core-shell structured fibers with poly(epsilon-caprolactone) as shell and bovine serum albumin (BSA)-containing dextran as core were prepared by coaxial electrospinning for incorporation and controlled release of proteins. BSA loading percent in the fibers and its release rate could be conveniently varied by the feed rate of the inner dope during electrospinning. With the increase in the feed rate of the inner dope, there was an associated increase in the loading percent and accelerated release of BSA. Poly(ethylene glycol) (PEG) was added to the shell section of the fibers to further finely modulate the release behavior of BSA. It was revealed that the release rate of BSA increased with the PEG percent in the shell section. By varying the feed rate of the inner dope and PEG content, most of BSA could be released from the core-shell structured fibers within the period of time ranging from 1 week to more than 1 month. The effect of the feed rate of the inner dope and addition of PEG into the shell section on the fiber morphology was also examined by scanning electron microscope.

Preparation and release behavior of carboxymethylated chitosan/alginate microspheres encapsulating bovine serum albumin

AbstractMicrospheres were prepared from carboxymethylated chitosan (CM‐chitosan) and alginate by emulsion phase separation. Their structure and morphology were characterized with IR spectroscopy and scanning electron microscopy. Bovine serum albumin (BSA) was encapsulated in the microspheres to test the release behavior. The swelling behavior, encapsulation efficiency, and release behavior of BSA from the microspheres at different pHs and with a pH‐gradient condition were investigated. The BSA encapsulation efficiency was calculated to be 80%. The degree of swelling of the microspheres without BSA loaded at pH 7.2 was much higher than that at pH 1.0. The encapsulated BSA was quickly released in a Tris–HCl buffer (pH 7.2), whereas a small amount of BSA was released under acid conditions (pH 1.0) because of the strong electrostatic interaction between NH2 groups of CM‐chitosan and COOH groups of alginic acid and a dense structure caused by a Ca2+ crosslinked bridge. For the simulation of the processing of the drug under the conditions of the intestine, the microspheres were tested in a pH‐gradient medium, in which an acceleration of the release occurred at pH 7.4 after a lag time at a low pH (5.8–6.8). At pH 7.4, a large amount of BSA was released from the microspheres in a short time because of the rapid swelling of the microspheres. However, the release only depended on the diffusion of BSA at relatively low pHs, this resulted in a relatively low release. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 878–882, 2004