Diethylaminoethyl Dextran Research Articles

Preparation, characterization of upconverting nanoparticles for uricase immobilization and controlled manipulation of uricase activity by near-infrared light

In recent years, studies on the external stimulation of biotechnological enzyme drugs and their use in the treatment of diseases have gradually increased. Herein, for the first time, the near-infrared (NIR) was used as an external stimulant to manipulate the catalytic activity of the uricase (UOx) enzyme, which is used in the treatment of hyperuricemia, in a controlled manner. For this purpose, NaYF4: Yb3+, Er3+ upconverting nanoparticles (UCNPs) were synthesized by hydrothermal synthesis method and functionalized with diethylaminoethyldextran (DEAE-D) to facilitate UOx immobilization. The obtained materials were characterized in detail by various methods to confirm the preparation of UCNPs and immobilization of UOx. In addition, the biochemical parameters such as optimum pH, optimum temperature, thermal stability, and reusability were preliminarily investigated for free UOx and NaYF4: Yb3+, Er3+/DEAE-D/UOx. Moreover, a sequential experimental method was monitored to assess the effects of NIR excitation intensity, induction distance, and exposure time on the UOx activity. While the optimum pH value was found to be 6.0 for both enzyme forms, the optimum temperature value was recorded as 45 and 50 °C for free UOx and NaYF4: Yb3+, Er3+/DEAE-D/UOx, respectively. The activation energy (Ea) values of free UOx and NaYF4: Yb3+, Er3+/DEAE-D/UOx were calculated to be 7.59 and 2.98 kJ/mol, respectively, implying that the NaYF4: Yb3+, Er3+/DEAE-D/UOx was less temperature sensitive. After thermal incubation for 3 h at 55 °C, the NaYF4: Yb3+, Er3+/DEAE-D/UOx retained 54.68 % of its initial activity, while the free UOx retained 32.94 % of its initial activity at 50 °C. In addition, the findings from the reusability experiments revealed that NaYF4:Yb3+, Er3+/DEAE-D/UOx retained 57.94 % of its initial activity even after 10 reuse cycles. The most striking point in this study was the positive manipulation of UOx activity by NIR. Accordingly, it was observed that when the NIR power was 1500 mW, the UOx activity increased about 2 times compared to the control. Additionally, the UOx activity increased in parallel with the increase in NIR application time and the ideal application distance was 3 cm. In conclusion, this pioneering study provides valuable insights into the controlled manipulation of enzyme activity, showcasing the effectiveness of NIR in enhancing enzyme activity. The outcomes suggest that NIR holds great promise as an efficient, sustainable, and versatile approach applicable to various enzymatic catalysis scenarios.

Magnetically controlled insertion of magnetic nanoparticles into membrane model

Polysaccharide–coated magnetic nanoparticles (MNPs) have been reported to show potential applications in many biomedical fields. In this report, we have studied the interactions between magnetite (Fe3O4) MNPs functionalized with polysaccharides (diethylamino–ethyl dextran, DEAE–D or chitosan, CHI) with different membranes models by Langmuir isotherms, incorporation experiments, and brewster angle microscopy (BAM). In this report, zwitterionic 1,2–distearoyl–sn–glycerol–3–phosphoethanolamine (DSPE) and anionic 1,2–distearoyl–sn–glycerol–3–phosphate (DSPA) phospholipid, were used to form membrane models. Incorporation experiments (π–t) as well as the compression isotherms demonstrate positive interactions between MNPs and DSPE or DSPA monolayers. The study assessed the impact of varying initial surface pressure on a preformed phospholipid monolayer to determine the maximum insertion pressure (MIP) and synergy. Our findings indicate that the primary driving force of the coated MNPs incorporation into the monolayer predominantly stems from electrostatic interaction. The drop in the subphase pH from 6.0 to 4.0 led to an enhancement of the MIP value for DSPA phospholipid monolayer. On the other hand, for DSPE, the drop in the pH does not affect the MIP values. Besides, the presence of a magnetic field induces an enhancement of the insertion process of the MNPs into DSPA preformed monolayer, demonstrating that a previous interaction between MNPs and phospholipid preformed monolayer needs to take place to enhance the incorporation process. This work opens novel perspectives for the research of the influence of magnetic fields on the incorporation of MNPs into model membranes.

Molecular Structure and Conformation of Biodegradable Water-Soluble Polymers Control Adsorption and Transport in Model Soil Mineral Systems.

Water-soluble polymers (WSPs) are used in diverse applications, including agricultural formulations, that can result in the release of WSPs to soils. WSP biodegradability in soils is desirable to prevent long-term accumulation and potential associated adverse effects. In this work, we assessed adsorption of five candidate biodegradable WSPs with varying chemistry, charge, and polarity characteristics (i.e., dextran, diethylaminoethyl dextran, carboxymethyl dextran, polyethylene glycol monomethyl ether, and poly-l-lysine) and of one nonbiodegradable WSP (poly(acrylic acid)) to sand and iron oxide-coated sand particles that represent important soil minerals. Combined adsorption studies using solution-depletion measurements, direct surface adsorption techniques, and column transport experiments over varying solution pH and ionic strengths revealed electrostatics dominating interactions of charged WSPs with the sorbents as well as WSP conformations and packing densities in the adsorbed states. Hydrogen bonding controls adsorption of noncharged WSPs. Under transport in columns, WSP adsorption exhibited fast and slow kinetic adsorption regimes with time scales of minutes to hours. Slow adsorption kinetics in soil may lead to enhanced transport but also shorter lifetimes of biodegradable WSPs, assuming more rapid biodegradation when dissolved than adsorbed. This work establishes a basis for understanding the coupled adsorption and biodegradation dynamics of biodegradable WSPs in agricultural soils.

Diethylaminoethyl-dextran and monocyte cell membrane coated 1,8-cineole delivery system for intracellular delivery and synergistic treatment of atherosclerosis

We have developed a biomimetic delivery system termed the Monocyte Cell Membrane-Coated 1,8-Cineole Biomimetic Delivery System (MM-CIN-BDS or BDS), which integrates diethylaminoethyl-dextran (DEAE) and monocyte cell membrane (MM). This innovative approach enhances the cellular uptake efficiency of 1,8-cineole (CIN) and facilitates targeted therapy for atherosclerosis. Our findings demonstrate the successful modification of the drug carrier with DEAE and MM, as validated by measurements of particle size, zeta potential, microscopic morphology, and western blotting analyses. Notably, cellular uptake experiments unveil a significant enhancement in cellular uptake efficiency due to DEAE modification. However, the introduction of monocyte cell membranes diminishes this effect in normal human umbilical vein endothelial cells (HUVECs), although this efficiency is notably restored in HUVECs activated with lipopolysaccharide (LPS). Through in vivo imaging investigations, we observe that the MM coating augments distribution in the spleen, brain, and atherosclerotic plaques, while concurrently diminishing distribution in the heart and kidneys. Animal studies corroborate these findings, illustrating that MM-CIN-BDS treatment curtails lipid parameters, dampens the expression of inflammatory factors and proteins, mitigates vascular tissue damage, and ultimately reduces the extent of atherosclerotic lesion areas. To encapsulate, DEAE emerges as an especially adept agent for modifying drug carriers with suboptimal cellular uptake efficiency in the realm of cardiovascular diseases. The potential therapeutic promise of MM-CIN-BDS for atherosclerosis treatment is evident from our research.

Opposite effects produced by magnetic nanoparticles:Phospholipid films generated at a liquid/liquid interface, in the drug transfer processes

The interaction between Fe3O4 magnetic nanoparticles (MNPs) coated with polysaccharides, and different phospholipids adsorbed at a water|1,2-dichloroethane interface, was studied employing cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and capacity curves. For this study, an anionic phospholipid, distearoyl phosphatidic acid (DSPA), and a zwitterionic phospholipid distearoyl phosphatidylethanolamine (DSPE) were used, which have the same carbonated chain. Fe3O4 nanoparticles were coated with two different polysaccharides, one lineal, chitosan (CHI), and other with a branched structure, diethylaminoethyl dextran (DEAE-D), both commonly used in medical applications. The effect of the MNPs coating agents in the final interaction with MNPs:phospholipid hybrid films was evaluated. EIS confirm that the presence of Fe3O4@CHI:DSPA mixture film conduces to a homogeneous film at the interface, in contrast, for Fe3O4@DEAE-D:DSPA mixture films, conduces to a inhomogeneous film with pores formation. In addition, the effect of this hybrid films (MNPs:phospholipid) in the anionic diclofenac (DCFNC−) and cationic triflupromazine (HTFPZ+) transfer process across the water|1,2-dichloroethane interface was studied. It was demonstrated that Fe3O4@CHI:DSPA film can totally block DCFNC− transfer process but for Fe3O4@DEAE-D:DSPA or DSPE film the DCFNC− can transfer across the uncovered zones present at the interface. Otherwise, for positively charged HTFPZ+, the drug transfer is higher in presence of MNPs:phospholipid mixture film due to a sum of effects, electrostatic interaction between HTFPZ+ and phospholipid and hydrophobic interactions between HTFPZ+ and polysaccharide coated MNPs.

Interaction between Pharmaceutical Drugs and Polymer-Coated Fe3O4 Magnetic Nanoparticles with Langmuir Monolayers as Cellular Membrane Models

Surface modification of magnetic nanoparticles (MNPs) has been reported to play a significant role in determining their interactions with cell membranes. In this research, the interactions between polymer functionalized (chitosan, CHI or diethylamino-ethyl dextran, DEAE-D) Fe3O4 MNPs, pharmaceutical drugs and model cell membranes were investigated by Langmuir isotherms and adsorption measurements. In this study, 1,2-distearoyl-sn-glycerol-3-phosphate (DSPA) phospholipid monolayers were used as cell membrane models. Insertion experiments demonstrate that diclofenac (DCFN) is not absorbed at the air-water interface, whereas triflupromazine (TFPZ) has a MIP (maximum insertion pressure) of 35 m Nm-1. The insertion of composites MNPs:TFPZ or DCFN has larger MIP values, indicating that the MNPs are adsorbed on the monolayer with the drugs. An Fe3O4@CHI:DCFN composite presented an MIP of 39 m Nm-1 and Fe3O4@DEAE-D:DCFN presented an impressive MIP of 67 mNm-1. In the case of TFPZ, the enhancement in the MIP values is also evident, being 42 mNm-1 for Fe3O4@CHI:TFPZ and 40 mNm-1 for Fe3O4@DEAE-D:DCFN composite. All MNPs:drugs composites have MIP values greater than commonly accepted membrane pressure values, indicating that MNPs:drugs can penetrate a cellular membrane. The fact that the composite MNPs:drugs present greater MIP values than separated compounds indicates that polymer-coated MNPs can act as good drug delivery systems.

Effect of bare and polymeric-modified magnetic nanoparticles on the drug ion transfer across liquid/liquid interfaces

The electrochemical behaviour of pharmaceutical drugs, namely triflupromazine and diclofenac, was investigated at the water/1,2 dicloroethane interface modified with magnetic nanoparticles (MNPs). Fe3O4 nanoparticles were obtained by co-precipitation method and coated with two different polymers, chitosan (CHI) and diethylaminoethyl dextran (DEAE-D), commonly used in medical applications. The effect of the MNP coating agents and the pH of the aqueous solution on the drug’s transfer process is evaluated. The MNPs coated with CHI interact strongly with both drugs, possibly due to the spatial distribution of the amine groups in its carbonated chain. The interaction between diclofenac anion and the ammonium groups of the polymer chain is also studied by DFT calculations. The results obtained in this work contribute to understanding the type of interactions between polymers, MNPs and drugs, which take place in a polarized interface.

Thermoresponsive nanogels based on polyelectrolyte complexes between polycations and functionalized hyaluronic acid

A novel kind of thermoresponsive polyelectrolyte complex-based nanogels (PEC-NGs) was elaborated by mixing hyaluronic acid (HA) functionalized with Jeffamine® M-2005 (M2005, a thermoresponsive amine-terminated polyether) and diethylaminoethyl dextran (DEAE-D) or poly-l-lysine (PLL) in water. The presence of M2005 grafts led to PEC-NGs with larger particle size, lower net surface charge and thermoresponsiveness, namely shrinkage with increasing hydrophobicity at higher temperature. Both M2005 grafts and replacing DEAE-D with PLL as polycation allowed PEC-NGs to have higher stability against salinity and better encapsulation of curcumin, most probably through intraparticle hydrophobic interactions, whereas interparticle hydrophobic interactions may facilitate particle aggregation over time. Curcumin encapsulation can be optimized by applying higher temperature during the complexation. Enzymatic degradability of PEC-NGs was also verified through particle size evolution in the presence of hyaluronidase. These results provide new insights into the physicochemical aspect of such systems as promising nanocarriers for drug delivery.

Grafting diethylaminoethyl dextran to macroporous cellulose microspheres: A protein anion exchanger of high capacity and fast uptake rate

Ion exchangers with high adsorption capacity and fast mass transfer synchronously are highly desired for protein separation and purification. For this purpose, here, we develop a high-performance anion exchanger by grafting diethylaminoethyl dextran (DEAE-dextran) on macroporous cellulose microspheres (MCMs). Static adsorption experiments for bovine serum albumin (BSA) show that the DEAE-dextran grafted MCMs have a higher adsorption capacity of 192.6 mg/mL than traditional non-grafted DEAE modified anion exchangers at a similar ionic capacity. The high adsorption capacity is due to the three-dimensionally extended polymer chains in pores that provide more and easily accessible ligands. Uptake kinetic results reveal that the DEAE-dextran grafted MCMs have a fast mass transfer rate and the maximum ratio (De/D0) of effective pore diffusivity (De) to free solution diffusivity (D0) reach 0.96, which is over three times higher than traditional non-grafted DEAE modified MCMs (0.29) and over nine times higher than commercial DEAE Sepharose FF (<0.10). It is attributed to the synergistic effect of the macropores and grafting ligands. The macropores provide wide channels for intraparticle pore diffusion, and the grafting ligands facilitate the surface transport of BSA by chain delivery occurred between adjacent DEAE-dextran chains. All these results demonstrate the DEAE-dextran grafted MCMs are promising as high-performance ion exchangers.

Functions of polyamines in growth and development of Phycomyces blakesleeanus wild-type and mutant strains

Polyamines are ubiquitous polycationic molecules with multiple effects. Spermidine was present in all the life stages of Phycomyces blakesleeanus, fulfilled the physiological requirement for polyamines during germination, and became most abundant at the emergence of germinating tubes. Putrescine was not found in resting spores or in stationary cultures, but was synthesized during apical growth and greatly exceeded spermidine in fast-growing stages of the vegetative and sexual life cycles. Changes in the polyamines did not correlate with the various stages of sporulation. Ornithine decarboxylase was so strongly inhibited in vitro by its product, putrescine, that it would completely block the enzyme if not compartmentalized away.1,4-Diamino-2-butanone inhibited mycelial growth throughout the vegetative cycle without killing the cells. The inhibition was counteracted very effectively by putrescine, which acts as a close analog of the inhibitor, and very little by spermidine.Four independent spe mutants were obtained by a procedure that selected for resistance to diaminobutanone among functionally-uninucleate spores that survived exposure to N-methyl-N′-nitro-N-nitrosoguanidine. The stability of the enzyme, in vivo and in vitro, and its inhibition by diaminobutanone in vitro were the same in the wild type and in the mutants. Two of these were hypomorph mutants, with lower affinity of their ornithine decarboxylase for its substrate, ornithine, and lower maximal velocity. The other two were hypermorph transport mutants; we propose that they are affected in a protein that binds putrescine and its analogs for transport across the plasmalemma and sequestration away from the active enzyme. The transport mutants concentrated the exogenous diaminobutanone and the endogenous putrescine in inactive compartments; the highest enzyme activity was reached when the plasmalemma of the mutants was permeabilized with diethylaminoethyl dextran.

Effect of magnetic nanoparticles coating on their electrochemical behaviour at a polarized liquid/liquid interface

• Fe 3 O 4 nanoparticles were coated with chitosan and DEAE-Dextran. • Interfacial properties in a liquid/liquid system were studied using cyclic voltammetry and electrochemical impedance spectroscopy. • MNPs@CHI exhibits higher catalytic effect and capacity charge values than MNPs@DEAE-D. • Fe 3 O 4 nanoparticles coated with chitosan and DEAE-Dextran are arranged at the interface like a homogeneous film. The interface between two immiscible electrolyte solutions (ITIES) can act as a platform for the assembly of nanoscale materials. Here, we study the effect of the coated magnetic nanoparticles most commonly used in biomedicine, on their interfacial properties, analysing the effect of applied potential on their interfacial behaviour, and the interactions that occur during these perturbations. The importance of this study is based on the similarity of the water/organic solvent interface with that generated at the cell membrane in the extra-cellular environment. Magnetite nanoparticles were successfully obtained by co-precipitation method, and were coated with chitosan and diethylaminoethyl dextran. Microstructure, magnetic properties and the electrochemical behaviour of the nanoparticles at liquid/liquid interfaces were studied. The presence of these nanoparticles at the interface facilitates the ion transfer process and increases the value of capacity charge, revealed by adsorption curves. These effects depend on the coating polymer and the amount of magnetic nanoparticles adsorbed at the interface, being higher for nanoparticles coated with chitosan. The main difference in the interfacial behaviour of the coated nanoparticles is due to the distribution of the amine groups in the chain of both polymers, since in chitosan the amine groups interact easily with ions present in both phases, because it has a linear structure, different from the branched diethylaminoethyl dextran. The results obtained in this work contribute to understanding the interactions between polymers and magnetic nanoparticles and demonstrate that liquid/liquid interfaces can be used successfully to analyse the effect that different coatings have on their interfacial behaviour.

Successive Multiple Ionic-Polymer Layer Coatings for Intact Protein Analysis by Capillary Zone Electrophoresis-Mass Spectrometry: Application to Hemoglobin Analysis.

Adsorption of analytes, e.g., proteins, often interfere with separation in CE, due to the relatively large surface of the narrow capillary. Coatings often are applied to prevent adsorption and to determine the electroosmotic flow (EOF), which is of major importance for the separation in CE. Successive multiple ionic-polymer layer (SMIL) coatings are frequently used for protein analysis in capillary electrophoresis resulting in high separation efficiency and repeatability. Here, the coating procedure of a five-layer SMIL coating is described using quaternized diethylaminoethyl dextran (DEAEDq) as polycation and poly(methacrylic acid) (PMA) as polyanion. Depending on the analyte, different polyions may be used to increase separation efficiency. However, the coating procedure remains the same.To demonstrate the applicability of SMIL coatings in CE-MS, human hemoglobin was measured in a BGE containing 2M acetic acid. DEAEDq-PMA coating was found to be the most suitable for hemoglobin analysis due to relatively low reversed electroosmotic mobility leading to increased electrophoretic resolution of closely related proteoforms. Thereby, not only alpha and beta subunit of the hemoglobin could be separated, but also positional isoforms of glycated and carbamylated species were separated within 24min.

Synthesis, characterization and biological applications of biofunctional gold nanoparticles for systemic circulation and biological sustainability

Designing nanomaterials for biomedical applications is not a trivial task. Avoidance of the immune system, stability in physiological media, and cell membranes, low toxicity, and optimal bioperformances are critical for the success of the designed nanomaterials. This review focuses on the study of protein-protein and protein-carbohydrates interactions. Most of the biological functions involving biochemical process are closely controlled by protein-protein interactions. Multi-protein complexes perform several catalytic functions. The review also focuses on the in vitro synthesis of bioconjugated nanoparticles and their biological applications such as antimicrobial agents and drug delivery vehicles. The synthesized nanoparticles act as sensor for such interactions. The in vitro synthesis of Au NPs also helps to understand such interactions with better clarity, which are otherwise elusive in the absence of NPs due to their highly complex nature. Both lysozyme (Lys) / Cytochrome, c (Cyt. c) and lysozyme/zein complexes showed remarkable surface adsorption on NP surfaces. The former system produced pH responsive NPs due to its amphiphilic nature and good antimicrobial properties while the latter system produced pH insensitive NPs due to its hydrophobic nature dominated by zein due to presence of non-polar amino acids such as leucine, alanine and proline. Due to insignificant hemolysis both systems may be used as drug delivery vehicles in systemic circulation. The diethylaminoethyl dextran chloride (DEAE) -protein interactions showed that DEAE-BSA and DEAE-Lys mixtures are amphiphilic whereas DEAE-zein mixture is hydrophobic in nature. All different complexes demonstrate strong surface adsorption on both presynthesized Au NPs as well as in vitro synthesis of Au NPs, which leads to the formation of biofunctional Au NPs best suited for biological applications in systemic circulation. The biological applicability is demonstrated from the hemolysis measurements where both DEAE−BSA as well as DEAE−Lys coated Au NPs do not show any marked hemolysis, thus proving to be the best suited vehicles for drug release in systemic circulation. DEAE−zein coated NPs, on the other hand, showed this behavior only in the DEAE rich region of the mixture, but in the protein rich region hemolysis dominates. Copyright © 2017 VBRI Press.

Polyelectrolyte complexes of hyaluronic acid and diethylaminoethyl dextran: Formation, stability and hydrophobicity

Polyelectrolyte complexes (PECs) of hyaluronic acid (HA) and diethylaminoethyl dextran (DEAE-D), promising for biomedical applications, have been investigated with respect to physicochemical properties, mainly in terms of particle size and relative hydrophobicity as well as storage stability. Influences of charge ratio, polymer concentration, molar masses of HA, ionic strength and mixing methods have been particularly investigated. The complexation between HA and DEAED generally resulted in colloidal particles having mean hydrodynamic diameter of 150–350 nm, with larger particle size observed at negative to positive charge ratio (n-/n+) further from the unity. Higher polymer concentration or higher molar mass of HA also led to higher particle size of the PECs, whereas the increasing ionic strength led to a non-monotonic evolution in particle size. The effects of mixing mode and mixing order on particle size were interdependent and depended also on n-/n+. PECs at n-/n+ ≤ 0.4 showed lack of stability, which seemed not to be sensitive to storage temperature but significantly improved at higher salt concentration or lower polymer concentration. The relative hydrophobicity of such PECs was also confirmed by the fluorescence spectra of pyrene incorporated in PEC particles. Such results gave a better insight to polysaccharides-based PECs, especially as a potential system to encapsulate hydrophobic active molecules for drug delivery purposes.

Non-intuitive Behavior of Polymer-Ciprofloxacin Nanoconjugate Suspensions: a Tool for Flexible Oral Drug Delivery.

Ciprofloxacin (CPX) is prone to spontaneous self-aggregation and formation of supramolecular dimers (π - π stacking) due to its complicated surface chemistry which has been associated with its anomalous solubility and instability in aqueous systems particularly near neutral pH. The surface characteristic of ciprofloxacin was modified through non-intuitive counterion interaction between CPX and diethylaminoethyl dextran (DDEX) to form nanoconjugate assembly. The CPX-DDEX nanoconjugate was confirmed by FTIR, SEM, DSC, TGA, and 1H-NMR. The DSC thermograms showed a remarkable 20% reduction in the melting temperature (Tm) of CPX from 268.57±1.11°C to 214.36±1.0211°C and 78% reduction in enthalpy of fusion (ΔHf) from 59.84 kJ/mol (180.59 J/g) to 12.90 kJ/mol (38.92 J/g), indicating increased solubility and dissolution efficiency. DDEX polymer alone exhibited pseudoplastic characteristics however with more viscous rather than elastic response, while the CPX-DDEX nanoconjugate suspensions exhibited remarkable elastic behavior with significantly increased storage modulus (G') thus controlling and extending the release of CPX. The reconstituted freeze-dried CPX-DDEX nanoconjugate suspension was chemically stable throughout the 90-day study both in the refrigerator and at controlled room temperature, while the aqueous suspension of pure CPX without DDEX was only stable for 72 and 24 h, respectively. The dissolution efficiency of the CPX-DDEX nanoconjugate suspensions increased with increasing molar concentration of DDEX to a maximum of 100% at 50 μM of DDEX followed by a remarkable decrease within the 3-week study. It was apparent that the dissolution efficiency was governed by a critical balance between the CPX solubility and the viscoelastic characteristics of the polymeric nanoassembly. This study demonstrates the potential application of polymer-drug nanoconjugation formulation design to stabilization and flexible delivery of CPX from aqueous suspension systems. Graphical abstract.

Improving the ameliorative effects of berberine and curcumin combination via dextran-coated bilosomes on non-alcohol fatty liver disease in mice

BackgroundThe combination of berberine (BER) and curcumin (CUR) has been verified with ameliorative effects on non-alcohol fatty liver disease (NAFLD). However, discrepant bioavailability and biodistribution of BER and CUR remained an obstacle to achieve synergistic effects. Multilayer nanovesicles have great potential for the protection and oral delivery of drug combinations. Therein lies bile salts inserted liposomes, named as bilosomes, that possesses long residence time in the gastrointestinal tract (GIT) and permeability across the small intestine. Diethylaminoethyl dextran (DEAE-DEX) is generally used as an outside layer on the nanovesicles to increase the mucinous stability and promote oral absorption. Herein, we developed a DEAE-DEX-coated bilosome with BER and CUR encapsulated (DEAE-DEX@LSDBC) for the treatment of NAFLD.ResultsDEAE-DEX@LSDBC with 150 nm size exhibited enhanced permeation across mucus and Caco-2 monolayer. In vivo pharmacokinetics study demonstrated that DEAE-DEX@LSDBC profoundly prolonged the circulation time and improved the oral absorption of both BER and CUR. Intriguingly, synchronized biodistribution of BER and CUR and highest biodistribution at liver was achieved by DEAE-DEX@LSDBC, which contributed to the optimal ameliorative effects on NAFLD. It was further verified to be mainly mediated by anti-oxidation and anti-inflammation related pathwaysConclusionDEAE-DEX coated bilosome displayed promoted oral absorption, prolonged circulation and synchronized biodistribution of BER and CUR, leading to improved ameliorative effects on NAFLD in mice, which provided a promising strategy for oral administration of drug combinations.Graphic abstract

Superiority of DEAE-Dx-Stabilized Cationic Bile-Based Vesicles over Conventional Vesicles for Enhanced Hepatic Delivery of Daclatasvir.

The purpose of our study was to improve the delivery of a direct-acting antiviral drug, daclatasvir, to the site of action, liver tissues, using physically and biologically stable cationic bile-based vesicles. Accordingly, cationic bile-based vesicles were prepared as pro-bile-based vesicles and diethylaminoethyl dextran (DEAE-Dx)-stabilized bile-based vesicles to increase their stability without negatively affecting their hepatic affinity. The prepared bile-based vesicles were characterized for particle size, polydispersity index, ζ-potential, in vitro daclatasvir release, and ex vivo permeation using non-everted gut sac intestine. The in vivo biodistribution was experimented after oral administration utilizing the radiolabeling assay, where the liver showed the highest accumulation of the DEAE-Dx-stabilized bile-based vesicles after 4 h, reaching a value of 4.6% ID/g of the total oral administered dose of the labeled drug compared to drug solution, pro-bile-based vesicles, and cationic bile-based vesicles where the accumulation was 0.19, 1.3, and 0.31% ID/g, respectively. DEAE-Dx-stabilized bile-based vesicles increased the drug deposition into the liver about 42-fold compared to oral solution. The high physical stability and the high resistance to opsonization and clearance show that DEAE-Dx-stabilized bile-based vesicles could be efficiently applied for enhancing daclatasvir delivery to the liver after oral administration.

Enzymatic degradation of the polymer capsules with a hydrophobic core in the presence of Langmuir lipid monolayer as a model of the cellular membrane

Submicrocapsules were prepared from diethylaminoethyl dextran (DEAE-D), xanthan gum (XG) and bovine serum albumin (BSA) on oil cores by ultrasonic treatment. These capsules were modified with poly-L-lysine (PLL) via electrostatic adsorption. The behavior of the capsules was investigated at an air–water interface after their introduction into an aqueous subphase. The interaction of the capsules with 1,2-Dimyristoyl-sn-glycero-3-phosphocholine (DMPC) monolayer formed on the water surface (model cellular membrane) was studied both upon their introduction under the condensed monolayer and with the use of a dilute colloidal solution of the capsules as a subphase. Biodegradation of the proteinaceous capsules with subsequent oil-core release was demonstrated by influence of pronase. The Langmuir lipid monolayer was found to be a good model for investigation of drug release from the capsules in the presence of the cellular membrane.

Rapid fluorescent focus inhibition test optimization and validation: Improved detection of neutralizing antibodies to rabies virus

The rabies rapid fluorescent focus inhibition test (RFFIT) is the most widely used cell-based assay for detecting and quantitating rabies virus neutralizing antibodies (RVNA) in human serum. However, it is a complex, labor intensive, and somewhat subjective manual assay, the performance of which may be affected by a number of factors including the quality of cells and virus, variability of assay reagents and the skill and expertise of analysts. This study sought to identify and evaluate conditions that may impact RFFIT performance and RVNA detection by evaluating assay parameters including: different serial dilution scheme of serum samples in a 96-well microplate using semi-automated pipetting systems, the range of dose of challenge virus standard (CVS-11) strain of rabies virus, the effect of complement (C′), the effect of cell seeding density and passage number, the effect of diethylaminoethyl (DEAE) dextran concentration on virus infectivity, and the assay incubation period prior to immunostaining. In addition the evaluation of counting fluorescent foci using a microscope versus using scanned images from a cell imaging reader was performed in an effort to ease the reading of slides and have permanent records of the raw data. The results from optimization of each parameter are presented along with subsequent assay validation in accordance with the International Conference on Harmonization (ICH) guidelines. The improved and optimized RFFIT accuracy, linearity and sensitivity was demonstrated by testing World Health Organization (WHO)-1 and WHO-2 Standard Rabies Immune Globulins (SRIGs) and complete assay development and validation was performed in compliance with Good Clinical Laboratory Practice (GCLP) guidelines.

Stabilization of Water-In-Water Emulsions by Linear Homo-Polyelectrolytes.

The effect of adding a small quantity of linear polymers on the stability of water-in-water (W/W) emulsions was studied for emulsions of dextran-rich droplets in a continuous poly(ethylene oxide) (PEO) phase (D/P) and vice versa (P/D). It was found that out of 16 different polymers that were tested, three had a significant effect: chitosan (Chit), diethyl aminoethyl dextran (DEAED), and propylene glycol alginate (PGA). In the presence of Chit or PGA, P/D emulsions were much less stable than D/P emulsions, but DEAED stabilized both types of emulsion. Interactions of these polymers with PEO or dextran were investigated with light scattering, and the microstructure of the emulsions was studied with confocal laser scanning microscopy. The effect of pH, polymer concentration, interfacial tension, and ionic strength on the stability was investigated and was found to be different for the three polymer types. The results suggest that stabilization of W/W emulsions by linear polymers requires that they contain both charged and hydrophobic units.