Cell response to the exposure to chitosan-TPP//alginate nanogels

Hydrophilic nanocarriers formed by electrostatic interaction of chitosan with oppositely charged macromolecules have a high potential as vectors in biomedical and pharmaceutical applications. However, comprehensive information about the fate of such nanomaterials in biological environment is lacking. We used chitosan from both animal and fungal sources to form well-characterized chitosan-pentasodium triphosphate (TPP)//alginate nanogels suitable for comparative studies. Upon exposure of human colon cancer cells (HT29 and CaCo2), breast cancer cells (MDA-MB-231 and MCF-7), glioblastoma cells (LN229), lung cancer cells (A549), and brain-derived endothelial cells (HCEC) to chitosan-(TPP)//alginate nanogels, cell type-, nanogel dosage-, and exposure time-dependent responses are observed. Comparing chitosan-TPP//alginate nanogels prepared from either animal or fungal source in terms of nanogel formation, cell uptake, reactive oxygen species production, and metabolic cell activity, no significant differences become obvious. The results identify fungal chitosan as an alternative to animal chitosan in particular if biomedical/pharmaceutical applications are intended.     

壳聚糖-三聚磷酸钠纳米粒对于肝组织严重出血模型的止血效果

目的:建立SD大鼠肝脏严重出血模型,考察壳聚糖-三聚磷酸钠(TPP)纳米粒的止血效果对于实质性器官严重出血的止血效果。方法:24只SD大鼠各分3组,每组8只,分为阴性对照组、壳聚糖-TPP组(NP组)和正常组,其中阴性对照组和NP组的大鼠建立肝脏严重出血模型。NP组,将壳聚糖-TPP纳米粒喷射到伤口,直至将整个伤口覆盖。阴性对照组,不使用任何止血材料处理创面。术后15天,用SEM和TEM观察NP组和阴性对照组的肝组织的微观结构。结果:通过组织学检查发现壳聚糖-TPP纳米粒在治疗严重伤口时能加速肉芽和大量胶原蛋白的生成,这正是伤口愈合初期的标志。结论:壳聚糖-TPP纳米粒对于严重出血的实质器官可发挥优良的止血性能,并能促使伤口愈合。     

还原可降解聚磺酸甜菜碱型纳米水凝胶的制备及载药研究

目的:制备与表征还原可降解的聚磺酸甜菜碱型纳米水凝胶,利用该纳米递药系统包载阿霉素(DOX)并初步评价其抗肿瘤性能。方法:利用回流沉淀聚合的方法合成含二硫键的聚磺酸甜菜碱甲基丙烯酸酯(PSBMA)纳米水凝胶及不含二硫键的PSBMA纳米凝胶(nd-PSBMA);通过粒度仪和透射电镜考察两种纳米水凝胶的粒径、形态以及稳定性;通过考察谷胱甘肽(GSH)对纳米凝胶溶液相对浊度的影响以评价还原环境对两种纳米凝胶的还原可降解性;利用纳米凝胶包载阿霉素(DOX),考察载药凝胶在GSH中的释药行为,并初步评价其对A549肿瘤细胞的杀伤作用。结果:以N, N'-双丙烯酰胱胺为交联剂制备了含二硫键的PSBMA纳米凝胶,其粒径在180～200 nm;同时以N, N'-双丙烯酰胺为交联剂制备了不含二硫键的n-PSBMA纳米凝胶。两种纳米凝胶与小鼠血清共孵育7天水合粒径仍无明显变化,表明磺酸甜菜碱型纳米凝胶具有良好的抗蛋白吸附能力。此外,PSBMA纳米凝胶在GSH溶液中迅速地降解,且降解速度与GSH浓度呈正相关;而nd-PSBMA纳米凝胶在GSH溶液中几乎不降解。载DOX的PSBMA纳米凝胶可在GSH作用下快速的释放药物而载DOX的nd-PSBMA纳米凝胶在GSH作用下缓慢的释放药物;体外细胞实验显示空白纳米凝胶和载药nd-PSBMA对A549细胞无明显毒性作用,但载DOX的PSBMA纳米凝胶可高效地杀死A549肿瘤细胞,其药效与游离DOX相仿。结论:还原可降解的PSBMA纳米水凝胶有望成为智能型控释药物载体。     

An investigation on skin wound healing in mice with a taurine-chitosan gel formulation

Summary. The process of wound healing begins immediately following surface lesions or just after exposure to radiation, chemical agents or extreme temperatures. Taurine (2-aminoethane sulfonic acid), an amino acid containing sulfur, is found in almost all tissues in mammals, playing various important physio-logical roles in each organ. Taurine exhibits an antioxidant effect and is also known to have effects on cell proliferation, inflammation and collagenogenesis. Many antioxidants have been used to eliminate the negative effects of oxygen free radicals on wound healing. The objective of the present study was to examine the wound healing effect in mice of taurine-chitosan gel, which releases taurine slowly over a long time period. Fifty mM of taurine in 1.5% chitosan polymer (TAU-GEL) and 1.5% chitosan polymer (CHI-GEL) were applied to full thickness skin wounds of mice once a day for seven days. After seven days of treatment, lipid peroxide formation-malondialdehyde (MDA) and hydroxyproline (HPX) levels and the tensile strength of wound tissues were measured. All results were compared with those of the untreated control group (CONT). The structural alterations in the skin layers were also histologically investigated. It was found that locally administered TAU-GEL form significantly increased wound tensile strength by decreasing the MDA and increasing HPX levels. These results were supported by histological findings. All observations suggest that taurine gel may be effective in wound healing. Received January 15, 2001 Accepted June 4, 2001     

Design of hybrid hydrogels with self-assembled nanogels as cross-linkers: interaction with proteins and chaperone-like activity

New hybrid hydrogels with nanogel domains were obtained by using polymerizable self-assembled nanogels as cross-linkers. Methacryloyl groups were introduced to cholesteryl group-bearing pullulan (CHP). The methacryloyl group-bearing CHPs (CHPMAs) formed nanogels by their self-association in water (R(g) = 14-17 nm). CHPMA nanogels were polymerized with 2-methacryloyloxyethyl phosphorylcholine (MPC) by radical polymerization in a semidilute aqueous solution. CHPMA nanogels acted as effective cross-linkers for gelation. TEM observation showed that the nanogel structure was retained after gelation and that the nanogels were well dispersed in the macrogel. The hybrid hydrogels showed two well-defined networks such as a nanogel intranetwork structure of less than 10 nm (physically cross-linking) and an internetwork structure of several hundred nanometers (chemically cross-linking). The immobilized nanogels retained their ability to trap and release protein (insulin was used as a model protein) by host-guest interaction of the cholesteryl group and cyclodextrin and also showed high chaperone-like activity for refolding of chemically denatured protein.     

Toxicity of Carum copticum essential oil‐loaded nanogel against Sitophilus granarius and Tribolium confusum

Myristic acid–chitosan (MA‐chitosan) nanogels were synthesized with the technique of self‐assembly and loaded with Carum copticum (L.) essential oil. Scanning electron microscopy (SEM) study indicated nanogels with smooth surfaces and near spherical appearance, and according to transmission electron microscopy (TEM) image, core–shell stricter of nanogels was reported. Subsequently, fumigant toxicity of C. copticum oil and oil‐loaded nanogels was assessed against Sitophilus granarius (L.) and Tribolium confusum Jacquelin du Val. Adults were exposed to different concentrations of the oil and oil‐loaded nanogels at 27 ± 1°C and 55 ± 5% r.h. in continuous darkness. The mortality was counted after 3, 6, 10, 24 and 48 h of exposure. Mortality increased with increasing concentration levels. Fumigant toxicity of oil‐loaded nanogels was significantly more than the oil even after 48 h. According to the findings, oil‐loaded nanogels were 8.9‐ and 3.7‐fold more toxic than the oil against S. granarius and T. confusum, respectively. The persistence of oil and oil‐loaded nanogels was also investigated over period of time. Oil‐loaded nanogels lost the insecticidal effectiveness after 21 days post‐application for S. granarius and 33 days in the case of T. confusum, while the efficacy of oil decreased in the early days of application. Chemical composition of C. copticum essential oil was measured, and six components were identified. Thymol, ρ‐cymene and γ‐terpinolene were the major components of the oil. The essential oil‐loaded nanogels may have potential to be used as an alternative to synthetic insecticides for stored products protection. However, more research is necessary to improve the findings.     

Biodegradable nanogel formation of polylactide-grafted dextran copolymer in dilute aqueous solution and enhancement of its stability by stereocomplexation

Monodisperse stereocomplex nanogels were obtained through the self-assembly of an equimolar mixture of dextran-graft-poly(L-lactide) (Dex-g-PLLA) and dextran-graft-poly(D-lactide) (Dex-g-PDLA) amphiphilic copolymers with well-defined composition in a dilute aqueous solution. The stereocomplex nanogel possessed partially crystallized cores of hydrophobic polylactide (PLA) and the hydrophilic dextran skeleton by intra- and/or intermolecular self-assembly between PLLA and PDLA chains. The stereocomplex nanogels exhibited significantly lower critical aggregation concentration (CAC) value as well as stronger thermodynamic stability compared with those of the corresponding L- or D-isomer nanogels. The mean diameter of the stereocomplex nanogels was 70 nm with narrow size distribution, implying they were well-defined and presumably nanogels. Furthermore, stereocomplex nanogel exhibited strong kinetic stability. The tunable degradation properties of Dex-g-PLA nanogels were achieved by varying the number of grafted PLA chains as well as applying stereocomplexation. This study demonstrates the advantage of stereocomplexation in the design of biodegradable nanogels with enhanced stability.     

Synthesis of chitosan networks: Swelling, drug release, and magnetically assisted BSA separation using Fe(3)O(4) nanoparticles

Chitosan (CS) nanohydrogel networks were prepared by reaction with glyceroldiglycidylether (GDE) and poly(dimethylsiloxane) (PDMS), as crosslinking agents in an emulsion system. The nanogel content increased with increasing the amount of crosslinkers and reached to a maximum of 90% with GDE. The nanogels structure was characterized by FT-IR, AFM, DSC, and TGA. The average size for CS-GDE and CS-PDMS particles were 59nm and 180nm, respectively. The swelling behavior of nanohydrogels was observed to be dependent on pH, temperature, degree of crosslinking, and on the chemical structure of crosslinker. The equilibrium water content of CS-GDE nanohydrogels reached to a maximum of 600% at neutral pH, and decreased at high and low pH and low temperature. These nanohydrogels were tested for sodium diclofenac (SDF) loading and releasing efficiency. The covalent conjugation of bovine serum albumin (BSA) and magnetic Fe(3)O(4) nanoparticles on the hydrogels were found to hold a potential application in magnetically assisted bioseparation.     

Chitosan nanogels by template chemical cross-linking in polyion complex micelle nanoreactors

Chitosan covalent nanogels cross-linked with genipin were prepared by template chemical cross-linking of chitosan in polyion complex micelle (PIC) nanoreactors. By using this method, we were able to prepare chitosan nanogels using only biocompatible materials without organic solvents. PIC were prepared by interaction between chitosan (X(n) = 23, 44, and 130) and block copolymer poly(ethylene oxide)-block-poly[sodium 2-(acrylamido)-2-methylpropanesulfonate] (PEO-b-PAMPS) synthesized by single-electron transfer-living radical polymerization (SET-LRP). PIC with small size (diameter about 50 nm) and low polydispersity were obtained up to 5 mg/mL. After cross-linking of chitosan with genipin, the nanoreactors were dissociated by adding NaCl. The dissociation of the nanoreactors and the formation of the nanogels were confirmed by (1)H NMR, DLS, and TEM. The size of the smallest nanogels was about 50 nm in the swollen state and 20 nm in the dry state. The amount of genipin used during reticulation was an important parameter to modulate the size of the nanogels in solution.     

Silver Sulfadiazine Nanosystems for Burn Therapy

The objective of the present study was to formulate stable silver sulfadiazine (SSD) nanosuspensions and nanogels suitable for topical delivery with a view to increase bactericidal activity in burn therapy. SSD nanosuspensions were formulated using the microprecipitation–high-pressure homogenization technique. An optimized microsuspension of 0.5% SSD formulated with 6% Cremophor EL and 4% Lauroglycol 90 was subjected to 30 cycles of 1,000-bar pressure to give a nanosuspension with an average particle size of 367.85 nm. Transmission electron microscopy studies revealed that ovoid- to rectangular-shaped SSD particles were present as clusters. It was evident through X-ray diffraction studies that SSD was present in amorphous state both in microprecipitate and in nanosuspension. SSD (0.5%) nanogels were prepared using 1% Carbopol 974 P for topical delivery of nanosized SSD. In vitro release studies demonstrated that SSD release was faster from solutions and nanosuspensions compared to gel formulation owing to the influence of the gel matrix on SSD release. The bacterial inhibitory efficiency of SSD nanosuspension was as good as that of SSD solution against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. In vivo studies revealed that a nanogel containing 0.5% SSD was more effective in wound healing compared to 0.5% and 1% marketed cream.     

Wet chemical synthesis of chitosan hydrogel–hydroxyapatite composite membranes for tissue engineering applications

Chitosan, a deacetylated derivative of chitin is a commonly studied biomaterial for tissue-engineering applications due to its biocompatibility, biodegradability, low toxicity, antibacterial activity, wound healing ability and haemostatic properties. However, chitosan has poor mechanical strength due to which its applications in orthopedics are limited. Hydroxyapatite (HAp) is a natural inorganic component of bone and teeth and has mechanical strength and osteoconductive property. In this work, HAp was deposited on the surface of chitosan hydrogel membranes by a wet chemical synthesis method by alternatively soaking the membranes in CaCl₂ (pH 7.4) and Na₂HPO₄ solutions for different time intervals. These chitosan hydrogel–HAp membranes were characterized using SEM, AFM, EDS, FT-IR and XRD analyses. MTT assay was done to evaluate the biocompatibility of these membranes using MG-63 osteosarcoma cells. The biocompatibility studies suggest that chitosan hydrogel–HAp composite membranes can be useful for tissue-engineering applications.     

Co-delivery of Vorinostat and Etoposide <Emphasis Type="Italic">Via</Emphasis> Disulfide Cross-Linked Biodegradable Polymeric Nanogels: Synthesis,Characterization, Biodegradation,and Anticancer Activity

Treatment regimens for cancer patients using single chemotherapeutic agents often lead to undesirable toxicity, drug resistance, reduced uptake etc. Combination of two or more drugs is therefore becoming an imperative strategy to overcome these limitations. A step forward can be taken through delivery of the drugs used in combination via nanoparticles. Co-administration of chemotherapeutic drugs encapsulated in nanoparticles has been shown to result in synergistic effects and enhanced therapeutic efficacy. In present study, we explored the combination treatment of histone deacetylase inhibitor vorinostat (VOR) and topoisomerase II inhibitor etoposide (ETOP). The concurrent combination treatment of VOR and ETOP resulted in synergistic effect on human cervical HeLa cancer cells. VOR and ETOP were encapsulated into poly(ethylene glycol) monomethacrylate (POEOMA)-based disulfide cross-linked nanogels. The nanogels were synthesized using atom transfer radical polymerization (ATRP) via cyclohexane/water inverse mini-emulsion and were degradable in presence of intracellular glutathione (GSH) concentration. Both the drugs were loaded into the nanogels by physical encapsulation method and characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), dynamic light scattering (DLS), and differential scanning calorimetry (DSC). Both VOR- and ETOP-loaded nanogels showed sustained release profile. Furthermore, combination treatment drugs encapsulated of POEOMA nanogel demonstrated enhanced synergistic cytotoxic effect compared with combination of free drugs. Enhanced synergistic cell killing efficiency of drug-loaded POEOMA nanogels was due to increased apoptosis via caspase 3/7 activation. Therefore, combination of VOR- and ETOP-loaded PEG-based biodegradable nanogels may provide a promising therapy with enhanced anticancer effect.     

Self-assembled dextrin nanogel as protein carrier: controlled release and biological activity of IL-10

Interleukin-10 (IL-10) is an anti-inflammatory cytokine, which active form is a non-covalent homodimer. Given the potential of IL-10 for application in various medical conditions, it is essential to develop systems for its effective delivery. In previous work, it has been shown that a dextrin nanogel effectively incorporated and stabilized rIL-10, enabling its release over time. In this work, the delivery system based on dextrin nanogels was further analyzed. The biocompatibility of the nanogel was comprehensively analyzed, through cytotoxicity (lactate dehydrogenase (LDH) release, MTS, Live, and Dead) and genotoxicity (comet) assays. The release profile of rIL-10 and its biological activity were evaluated in vivo, using C57BL/6 mice. Although able to maintain a stable concentration of IL-10 for at least 4 h in mice serum, the amount of protein released was rather low. Despite this, the amount of rIL-10 released from the complex was biologically active inhibiting TNF-α production, in vivo, by LPS-challenged mice. In spite of the significant stabilization achieved using the nanogel, rIL-10 still denatures rather quickly. An additional effort is thus necessary to develop an effective delivery system for this cytokine, able to release active protein over longer periods of time. Nevertheless, the good biocompatibility, the protein stabilization effect and the ability to perform as a carrier with controlled release suggest that self-assembled dextrin nanogels may be useful protein delivery systems.     

Doxorubicin-loaded pH-responsive chitin nanogels for drug delivery to cancer cells

This work deals with preparation of doxorubicin loaded chitin nanogels and were characterized by SEM, DLS and FTIR for cancer drug delivery. The in vitro cytotoxicity studies of 130-160 nm sized doxorubicin loaded chitin nanogels were studied using MTT assay on L929, PC3, MCF-7, A549 and HEPG2 confirmed that relatively higher toxicity on cancer cells comparing to normal L929 cells. The internalization studies showed a significant uptake of doxorubicin loaded chitin nanogels in all the tested cell lines. All the above results indicated that doxorubicin loaded chitin nanogels can be used for prostate, breast, lung and liver cancer.     

Carotenoid-containing unilamellar liposomes loaded with glutathione: a model to study hydrophobic-hydrophilic antioxidant interaction

Unilamellar liposomes are used as a simple two-compartment model to study the interaction of antioxidants. The vesicle membrane can be loaded with lipophilic compounds such as carotenoids or tocopherols, and the aqueous core space with hydrophilic substances like glutathione (GSH) or ascorbate, mimicking the interphase between an aqueous compartment of a cell and its surrounding membrane.

Unilamellar liposomes were used to investigate the interaction of GSH with the carotenoids lutein, β-carotene and lycopene in preventing lipid peroxidation. Lipid peroxidation was initiated with 2,2'-azo-bis-[2,4-dimethylvaleronitrile] (AMVN). Malondialdehyde (MDA) formation was measured as an indicator of oxidation; additionally, the loss of GSH was followed. In liposomes without added antioxidant, MDA levels of 119 ± 6 nmol/mg phospholipid were detected after incubation with AMVN for 2 h at 37°C. Considerably lower levels of 57 ± 8 nmol MDA/mg phospholipid were found when the liposomal vesicles had been loaded with GSH. Upon incorporation of β-carotene, lycopene or lutein, the resistance of unilamellar liposomes towards lipid peroxidation was further modified. An optimal further protection was observed with 0.02 nmol β-carotene/mg phospholipid or 0.06 nmol lycopene/mg phospholipid. At higher levels both these carotenoids exhibited prooxidant effects. Lutein inhibited lipid peroxidation in a dose-dependent manner between 0.02 and 2.6 nmol/mg phospholipid. With increasing levels of lycopene and lutein the consumption of encapsulated GSH decreased moderately, and high levels of β-carotene led to a more pronounced loss of GSH.

The data demonstrate that interactions between GSH and carotenoids may improve resistance of biological membranes towards lipid peroxidation. Different carotenoids exhibit specific properties, and the level for optimal protection varies between the carotenoids.     

Biocompatibility of mannan nanogel—safe interaction with plasma proteins

Background

Self-assembled mannan nanogels are designed to provide a therapeutic or vaccine delivery platform based on the bioactive properties of mannan to target mannose receptor expressed on the surface of antigen-presenting cells, combined with the performance of nanogels as carriers of biologically active agents.

Methods

Proteins in the corona around mannan nanogel formed in human plasma were identified by mass spectrometry after size exclusion chromatography or centrifugation followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Structural changes and time dependent binding of human apolipoprotein A-I (apoA-I) and human serum albumin (HSA) to mannan nanogel were studied using intrinsic tryptophan fluorescence and circular dichroism spectroscopy. The mannan nanogel effect on blood coagulation and fibrillation of Alzheimer's disease-associated amyloid β peptide and hemodialysis-associated amyloidosis β2 microglobulin was evaluated using thrombin generation assay or thioflavin T fluorescence assay, respectively.

Results

The protein corona around mannan nanogel is formed through a slow process, is quite specific comprising apolipoproteins B-100, A-I and E and HSA, evolves over time, and the equilibrium is reached after hours to days. Structural changes and time dependent binding of apoA-I and HSA to mannan nanogel are minor. The mannan nanogel does not affect blood coagulation and retards the fibril formation.

Conclusions

Mannan nanogel has a high biosafety and biocompatibility, which is mandatory for nanomaterials to be used in biomedical applications.

General Significance

Our research provides a molecular approach to evaluate the safety aspects of nanomaterials, which is of general concern in society and science.     

Cross-linked hydroxypropyl-β-cyclodextrin and γ-cyclodextrin nanogels for drug delivery: Physicochemical and loading/release properties

Due to their size and high surface-to-volume ratio, nanogels can give some unique drug delivery opportunities. A novel technique to prepare cyclodextrin (CD) nanogels, in which the cross-linking takes place simultaneously with an emulsification/solvent evaporation process, has been implemented. The aqueous phase consisted of γ-cyclodextrin (γCD) or hydroxypropyl-β-cyclodextrin (HPβCD) at a fix concentration of 20% (w/w) with or without hydroxypropyl methylcellulose (HPMC) or agar at various concentrations. The incorporation of the cross-linking agent, ethyleneglycol diglycidyl ether (EGDE), was essential for the nanogel formation. By contrast, nanogels could be formed in the absence of surfactant such as Span 80, which can be attributed to the emulsion stabilizing effect of CDs by forming inclusion complexes with the organic solvent at the interface. Gas chromatography-mass spectrometry (GC-MS) analysis of the nanogels confirmed that dichloromethane levels were below the safety limit and, therefore, that these conditions of the organic solvent evaporation (60 °C for 180 min) led to nanogels that satisfy residual solvent requirements. Infrared analysis (IR), transmission electron microscopy (TEM) and dynamic light scattering (DLS) provided information about the cross-linking degree, the size and the size distribution of the nanogels. The ability of the nanogels to host a molecule that can form inclusion complexes and to sustain its release was tested using 3-methylbenzoic acid (3-MBA) as a probe with a high affinity for both β-cyclodextrin (βCD) and γCD. Permeability tests confirmed that 3-MBA was indeed taken up by the nanogels and then slowly released.     

Nesfatin-1 improves oxidative skin injury in normoglycemic or hyperglycemic rats

Hyperglycemia is one of the major causes of suppressed angiogenesis and impaired wound healing leading to chronic wounds. Nesfatin-1 a novel peptide was reported to have antioxidant and anti-apoptotic properties. This study is aimed to investigate the potential healing-promoting effects of nesfatin-1 in non-diabetic or diabetic rats with surgical wounds. In male Sprague-Dawley rats, hyperglycemia was induced by intraperitoneal (ip) injection of streptozotocin (55 mg/kg). Under anesthesia, dorsum skin tissues of normoglycemic (n = 16) and hyperglycemic rats were excised (2 × 2 cm, full-thickness), while control rats (n = 16) had neither hyperglycemia nor wounds. Half of the rats in each group were treated ip with saline, while the others were treated with nesfatin-1 (2 μg/kg/day) for 3 days until they were decapitated. Plasma interleukin-1-beta (IL-1β), transforming growth factor-beta (TGF-β-1), IL–6 levels, and dermal tissue malondialdehyde (MDA), glutathione (GSH) levels, myeloperoxidase (MPO) and caspase-3 activity were measured. For histological examination, paraffin sections were stained with hematoxylin-eosin or Masson’s trichrome and immunohistochemistry for vascular endothelial growth factor (VEGF) was applied. ANOVA and Student’s t-tests were used for statistical analysis. Compared to control rats, skin MPO activity, MDA and caspase-3 levels were increased similarly in saline-treated normo- and hyperglycemic rats. Nesfatin-1 depressed MDA, caspase-3, MPO activity and IL-1β with concomitant elevations in dermal GSH and plasma TGF-β-1 levels. Histopathological examination revealed regeneration of epidermis, regular arrangement of collagen fibers in the dermis and a decrease in VEGF immunoreactivity in the epidermal keratinocytes of nesfatin-1-treated groups. Nesfatin-1 improved surgical wound healing in both normo- and hyperglycemic rats via the suppression of neutrophil recruitment, apoptosis and VEGF activation.     

Carotenoid-containing unilamellar liposomes loaded with glutathione: a model to study hydrophobic-hydrophilic antioxidant interaction

Unilamellar liposomes are used as a simple two-compartment model to study the interaction of antioxidants. The vesicle membrane can be loaded with lipophilic compounds such as carotenoids or tocopherols, and the aqueous core space with hydrophilic substances like glutathione (GSH) or ascorbate, mimicking the interphase between an aqueous compartment of a cell and its surrounding membrane.

Unilamellar liposomes were used to investigate the interaction of GSH with the carotenoids lutein, β-carotene and lycopene in preventing lipid peroxidation. Lipid peroxidation was initiated with 2,2′-azo-bis-[2,4-dimethylvaleronitrile] (AMVN). Malondialdehyde (MDA) formation was measured as an indicator of oxidation; additionally, the loss of GSH was followed. In liposomes without added antioxidant, MDA levels of 119 ± 6 nmol/mg phospholipid were detected after incubation with AMVN for 2 h at 37°C. Considerably lower levels of 57 ± 8 nmol MDA/mg phospholipid were found when the liposomal vesicles had been loaded with GSH. Upon incorporation of β-carotene, lycopene or lutein, the resistance of unilamellar liposomes towards lipid peroxidation was further modified. An optimal further protection was observed with 0.02 nmol β-carotene/mg phospholipid or 0.06 nmol lycopene/mg phospholipid. At higher levels both these carotenoids exhibited prooxidant effects. Lutein inhibited lipid peroxidation in a dose-dependent manner between 0.02 and 2.6 nmol/mg phospholipid. With increasing levels of lycopene and lutein the consumption of encapsulated GSH decreased moderately, and high levels of β-carotene led to a more pronounced loss of GSH.

The data demonstrate that interactions between GSH and carotenoids may improve resistance of biological membranes towards lipid peroxidation. Different carotenoids exhibit specific properties, and the level for optimal protection varies between the carotenoids.     

5-fluorouracil loaded fibrinogen nanoparticles for cancer drug delivery applications

In this study, 5-flurouracil loaded fibrinogen nanoparticles (5-FU-FNPs) were prepared by two step coacervation method using calcium chloride as cross-linker. The prepared nanoparticles were characterized using DLS, SEM, AFM, FT-IR, TG/DTA and XRD studies. Particle size of 5-FU-FNPs was found to be 150-200 nm. The loading efficiency (LE) and in vitro drug release was studied using UV spectrophotometer. The LE of FNPs was found to be ～90%. The cytotoxicity studies showed 5-FU-FNPs were toxic to MCF7, PC3 and KB cells while they are comparatively non toxic to L929 cells. Cellular uptake of Rhodamine 123 conjugated 5-FU-FNPs was also studied. Cell uptake studies demonstrated that the nanoparticles are inside the cells. These results indicated that FNPs could be useful for cancer drug delivery.