Sorafenib tosylate incorporation into mesoporous starch xerogel for in-situ micronization and oral bioavailability enhancement.

Poorly water-soluble drugs like sorafenib tosylate (SFB) can be made more soluble and orally bioavailable using a biocompatible hydrophilic matrix yields amorphous or microcrystalline drugs with high stability and low recrystallization risk. Mesoporous starch (MPS) due to its edibility, biodegradability, high surface area, and confined pores. In this study, MPS, either alone or in combination with polyvinylpyrrolidone (PVP), was employed for improving SFB oral bioavailability. To this aim, MPS was prepared in three steps: gelatinization, solvent exchange, and vacuum drying, after which it was used to incorporate SFB at various ratios using the immersion/solvent evaporation technique. Nitrogen adsorption/desorption analysis, Fourier transform infrared spectrometry (FTIR), field emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD) crystallography, and differential scanning calorimetry (DSC) were used to characterize SFB-loaded and drug-free samples, which confirmed the successful preparation of mesoporous structures with desirable uniform porosity, small pore size (about 5.3 nm), and specific surface area of about 24 m2/g. In-vitro dissolution testing revealed that the SFB dissolution rate increased substantially for the loaded MPS or MPS-PVP samples. Furthermore, when SFB was loaded in MPS-PVP, single-dose pharmacokinetics in rats confirmed an enhanced oral absorption kinetic. Therefore, impregnation of poorly soluble drugs such as SFB in the PVP-modified MPS excipient, which is constructed from a combination of mesoporous materials and a drug recrystallization inhibitor such as hydrophilic polymers, is proposed as a promising strategy for desirable enhancements in drug solubility, oral bioavailability, and efficacy.

Evaluation of the efficacy of albendazole sulfoxide (ABZ-SO)-loaded chitosan-PLGA nanoparticles in the treatment of cystic echinococcosis in laboratory mice.

Albendazole is known as the drug of choice for medical treatment of cystic echinococcosis (CE). Albendazole sulfoxide (ABZ-SO), as the main active metabolite of albendazole, has low efficacy in the disease due to low water solubility and poor absorptivity. PLGA nanoparticles (NPs) enhance the dissolution of poorly soluble drugs, and chitosan (CS) coating enhances oral drug delivery of NPs. In this study, the efficacy of ABZ-SO-loaded CS-PGLA NPs in the treatment of CE was evaluated in laboratory mice. ABZ-SO-loaded CS-PGLA NPs were prepared by nanoprecipitation and characterized by dynamic light scattering method and scanning electron microscopy. Thirty mice were intraperitoneally infected by 1000 protoscoleces of Echinococcus granulosus. Ten months later, the mice were allocated into 3 groups: groups 1 and 2 were treated with ABZ-SO and ABZ-SO-loaded CS-PGLA NPs, respectively, and the mice in group 3 remained untreated as the control group. The drugs were administered by gavage for 45 days at a daily dose of 10 mg/kg. Finally, all mice were opened and the cysts were collected, counted, weighed, and measured separately. The therapeutic effect of ABZ-SO in the number, weight, and volume of the cysts were not statistically significant compared with those in ABZ-SO-loaded CS-PGLA NPs and the control group. However, the therapeutic effect of ABZ-SO-loaded CS-PGLA NPs in the weight and volume of cysts were statistically significant when compared with that in the control group (p ˂ 0.05). In conclusions, this study revealed that ABZ-SO-loaded CS-PGLA NPs could enhance the therapeutic efficacy of ABZ-SO in the treatment of CE in laboratory mice.

Physicochemical and biological characteristics of the nanostructured polysaccharide-iron hydrogel produced by microorganism Klebsiella oxytoca.

There is an increasing interest in the nanostructured polysaccharide-iron hydrogel produced by Klebsiella oxytoca. Critical physicochemical and biological characteristics of these nanostructures should be revealed for biomedical applications. Accordingly, an iron reducing strain K. oxytoca, which synthesizes biogenic polysaccharide-iron hydrogel nanoparticles, known as Fe (III)-exopolysaccharide (Fe-EPS) was isolated from a mineral spring. For microbiological identification purpose 16S rRNA sequence analysis and different morphological, physiological, and biochemical characteristics of the isolate were studied. Critical physicochemical and biological characteristics of the produced Fe-EPS were evaluated using transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray crystallography (XRD), vibrating sample magnetometer (VSM). In addition, for the first time, Fe-EPS which synthesized by K. oxytoca was evaluated by dynamic light scattering (DLS), thermo gravimetric analysis (TGA), and cytotoxicity assay. TEM micrographs showed that the biogenic Fe-EPS is composed of ultra-small (about 1.8 nm) iron oxide nanoparticles (IONs) which are trapped in a polysaccharide matrix. The matrix was about 17% (w/w) of Fe-EPS total weight and provided a large negative charge of -71 mV. Interestingly, Fe-EPS showed a growth promotion effect on hepatocarcinoma cell line (Hep-G2) and 36% increase in the percentage of viability was observed by 24 h exposure to 500 µg ml-1 Fe-EPS.

Effect of lipid composition on incorporation of trastuzumab-PEG-lipid into nanoliposomes by post-insertion method: physicochemical and cellular characterization.

CONTEXT: Anti-HER2 immunoliposomes are promising nanotechnology based systems for active targeting of breast tumors, which depends on the amount of incorporated antibody. OBJECTIVE/AIM: In this work, we investigated the possible effect of lipid composition on the incorporation of trastuzumab-PEG-PE micelles into nanoliposomes and on their subsequent specific cellular targeting. MATERIALS AND METHODS: Trastuzumab (anti-HER2 monoclonal antibody) was monothiolated and conjugated to maleimide-PEG-PE micelles. Liposomes of different lipid compositions were prepared by the thin layer hydration. Trastuzumab-PEG-PE micelles were incorporated into the liposomes by the post-insertion method. The percentage of lipid mixing was determined based on fluorescence resonance energy transfer. Cellular binding and uptake of rhodamine-labeled immunoliposomes were studied in SKBR-3 (HER2(+++)) and MCF-7 (HER2(+)) cells. Also, antitumor cell activity of the immunoliposomes was compared to free trastuzumab and the liposomes. RESULTS: The lipid mixing of trastuzumab-PEG-PE micelles depended on the liposome composition. The immunoliposomes containing DPPC, cholesterol and PEG-PE showed prominent lipid mixing. The lipid mixing was consistent with the cell binding results which showed an efficient and specific binding of the immunoliposomes to SKBR-3 cells. Antitumor cell activity of the immunoliposomes in SKBR-3, unlike MCF-7 cells, depended on the content of trastuzumab. DISCUSSION: Cholesterol and PEG-PE in the liposome composition are prerequisites for a successful lipid mixing due to their ability to facilitate fusion. The higher lipid mixing results in higher antibody incorporation and consequently higher targeted cell binding. CONCLUSIONS: The lipid mixing depends on the liposome composition, which reflects targeted cell binding of the immunoliposomes.

Microencapsulation of (deoxythymidine)20-DOTAP complexes in stealth liposomes optimized by Taguchi design.

Stealth liposomes encapsulating oligonucleotides are considered as promising non-viral gene delivery carriers; however, general preparation procedures are not capable to encapsulate nucleic acids (NAs) efficiently. In this study, the lyophobic complexes of deoxythymidine20 oligonucleotide (dT20) and DOTAP were used instead of free dT20 for nano-encapsulation process by reverse phase evaporation method. Regarding the various factors that can potentially affect the liposome characteristics, Taguchi design was applied to analyze the simultaneous effects of factors comprising PEG-lipid (%), dT20/total lipid molar ratio, cholesterol (Chol%) and organic-to-aqueous phase ratio (o/w) at three levels. The response variables, hydrodynamic diameter, loading efficiency (LE%) and capacity (LC%), were studied by dynamic light scattering and ethidium bromide exclusion assay, respectively. The optimum condition described by minimum particle size as well as high LE% and LC% was obtained at 5% PEG-lipid, dT20/total lipid of 7, 20% Chol and o/w of 3 with an average size of 84 nm, LE% = 83.4% and LC% = 11.6%. Moreover, stability assessments in presence of heparin sulfate revealed the noticeable resistance, unlike DOTAP/dT20 lipoplexes, to premature release of NA. Transmission electron microscopy confirmed formation of discrete and circular vesicles encapsulating dT20.

Harnessing the Potential of Self-Assembled Peptide Hydrogels for Neural Regeneration and Tissue Engineering.

Spinal cord injury, traumatic brain injury, and neurosurgery procedures usually lead to neural tissue damage. Self-assembled peptide (SAP) hydrogels, a type of innovative hierarchical nanofiber-forming peptide sequences serving as hydrogelators, have emerged as a promising solution for repairing tissue defects and promoting neural tissue regeneration. SAPs possess numerous features, such as adaptable morphologies, biocompatibility, injectability, tunable mechanical stability, and mimicking of the native extracellular matrix. This review explores the capacity of neural cell regeneration and examines the critical aspects of SAPs in neuroregeneration, including their biochemical composition, topology, mechanical behavior, conductivity, and degradability. Additionally, it delves into the latest strategies involving SAPs for central or peripheral neural tissue engineering. Finally, the prospects of SAP hydrogel design and development in the realm of neuroregeneration are discussed.

Improving cellular uptake and in vivo tumor suppression efficacy of liposomal oligonucleotides by urea as a chemical penetration enhancer.

BACKGROUND: Liposomes are among the most widely used carriers for the delivery of antisense oligonucleotides (AsODNs) to intracellular targets. Although different strategies have been employed, the question of how to improve liposomal uptake and enhance the release of AsODN into cytoplasm still remains to be answered with respect to the use of a safe, easy and economic method. In the present study, the possibility of enhancing such processes at cellular and animal levels using urea as a penetration enhancer was investigated. METHODS: To perform this investigation, a cationic liposome containing an AsODN against protein kinase (PKC)-α was prepared, and the effect of urea on its cellular internalization and the related sequence-specific inhibition of gene expression in human lung adenocarcinoma A549 cells were investigated by flow cytometry and the reverse transcriptase-polymerase chain reaction, respectively. In in vivo studies, a xenograft lung tumor was established in nude mice by A549 cells and the enhancement effect of urea toward the effects of liposomal AsODN on tumor growth was investigated. RESULTS: Cellular studies revealed that urea treatment increases liposomal uptake and the release of AsODN into the cytoplasm by approximately 40%. Sequence-specific inhibition of target gene PKC-α expression was also increased by approximately two-fold by urea at 200-300 nM AsODN. In animal studies, urea significantly decreased the tumor volume (approximately 40%) and increased its doubling time from approximately 13 days to 17 days. CONCLUSIONS: Urea, and possibly other membrane fluidizers, could be regarded as penetration enhancers for liposomal AsODN delivery and may improve the therapeutic effect of these gene-therapy vectors at both cellular and animal levels.

L-asparaginase immobilization in supramolecular nanogels of PEG-grafted poly HPMA and bis(α-cyclodextrin) to enhance pharmacokinetics and lower enzyme antigenicity.

L-asparaginase (ASNase) enzyme has limited therapeutic use due to its poor pharmacokinetics and immunogenicity. To overcome these obstacles, we immobilized ASNase in biocompatible poly hydroxypropyl methacrylamide (P(HPMA))-based nanogels simply formed through the host-guest inclusion complex of ASNase-conjugated random copolymer of HPMA and polyethylene glycol (PEG) acrylate (P(HPMA-MPEGA)) and α-cyclodextrin dimer (bisCD) using cystamine as a linker. The effects of bisCD and polymer concentrations on particle size, gelation time, and recovery of enzyme activity were investigated. The ASNase-conjugated bisCD nanogels were discrete, homogeneous, and spherical with a mean projected diameter of 148 ± 41 nm. ASNase immobilized in the bisCD nanogels caused cytotoxicity on HL-60 cell line with IC50 of 3 IU/ml. In-vivo rat study revealed that the immobilized ASNase reduced the enzyme antigenicity and resulted in 8.1 folds longer circulation half-life than the native enzyme. Conclusively, immobilization of ASNase in P(HPMA-MPEGA) and bisCD supramolecular nanogels could enhance the therapeutic value of ASNase in cancer chemotherapy.

Amphiphilic hyperbranched polyglycerol nanoarchitectures for Amphotericin B delivery in Candida infections.

Although Amphotericin B (AMB) is considered the most effective anti-mycotic agent for treating Candida infections, its clinical use is limited due to its high toxicity. To address this issue, we developed cholesterol-based dendritic micelles of hyperbranched polyglycerol (HPG), including cholesterol-cored HPG (Chol-HPG) and cholesterol end-capped HPG (HPG@Chol), for AMB delivery. The findings suggested that the presence of cholesterol moieties could control AMB loading and release properties. Dendritic micelles inhibited AMB hemolysis and cytotoxicity in HEK 293 and RAW 264.7 cell lines while increasing antifungal activity against C. albicans biofilm formation. Furthermore, significantly lower levels of renal and liver toxicity biomarkers compared to Fungizone® ensured AMB-incorporated dendritic micelle biosafety, which was confirmed by histopathological evaluations. Overall, the Chol-HPG and HPG@Chol dendritic micelles may be a viable alternative to commercially available AMB formulations as well as an effective delivery system for other poorly soluble antifungal agents.

Comparison of binary cress seed mucilage (CSM)/ß-lactoglobulin (BLG) and ternary CSG-BLG-Ca (calcium) complexes as emulsifiers: Interfacial behavior and freeze-thawing stability.

Protein-polysaccharide complexes often exhibit amended techno-functional characteristics when compared to their individual participant biomolecules. In this study, a complex coacervation of cress seed mucilage (CSM)/ß-lactoglobulin (Blg) was used for stabilizing oil-in-water emulsions; they were characterized in terms of physical properties, droplet-size distribution and microstructure. Also, a comprehensive study was carried out on interfacial rheological responses and on the corresponding emulsion stability of different complexes. Freeze-thaw stability of the produced emulsions which had from mixtures of CSM-Blg was also evaluated. More than the size of droplets, interfacial rheological characteristics were associated with the properties of the adsorbed layers and with the stability of emulsions in storage. Using the CSM-Blg-Ca ultimately resulted in emulsions that proved stable against creaming, with no sign of phase separation over 3 weeks. These results show protein-polysaccharide complexes as appropriate emulsifiers that can make emulsion-based products resistant to unwanted changes caused by freeze-thawing.

Paclitaxel-loaded polypeptide-polyacrylamide nanomicelles overcome drug-resistance by enhancing lysosomal membrane permeability and inducing apoptosis.

The aim of the current project was to investigate the in vitro properties of Paclitaxel (PTX)-loaded pHPMA5kD -pHis5kD -pLeu3kD nanomicelles (NMs) on multidrug resistance cell line. Circular dichroism analysis was done to investigate the effect of pH on the secondary structure of the copolymer. Cytotoxicity assay together with fluorescence imaging and flow cytometry were performed to get an insight about toxicity and cellular uptake mechanism of NMs. Acridine orange assay, rhodamine 123 (Rh123) accumulation assay, and apoptosis analysis were conducted for further investigation. It was found that the secondary structure of the copolymer changed in response to pH, PTX-loaded NMs had higher cytotoxicity on both drug-sensitive (MES-SA and MCF-7) and multidrug resistant cells (MES-SA/DX5) compared to free PTX, and interestinly free copolymer inhibited the growth of MES-SA/DX5 cells while it was nontoxic on drug-sensitive cells. Moreover, the copolymer was able to induce lysosome membrane permeation and increase Rh123 accumulation inside cells indicating inhibition of the P-gp efflux pumps. Finally, apoptosis was strongly induced in MES-SA/DX5 cells upon treatment with PTX-loaded NMs. It can be concluded that the designed hybrid copolymer is a good candidate for in vivo assay and developing a powerful system against multidrug resistance tumors.

Hyperbranched polyglycerol nanostructures for anti-biofouling, multifunctional drug delivery, bioimaging and theranostic applications.

Nowadays, great attention has been paid to the design and development of novel macromolecular constructions in drug delivery. Hyperbranched polymers (HBPs) are amongst various types of polymeric structures with exceptional physicochemical properties and biomedical applications relevant to their dendritic structure. Unlike perfect dendrimers, HBPs can be produced via one-step polymerization reactions. Moreover, they can be applied as building blocks in preparing dendronized, dendrigraft or dendritic nanostructures. Hyperbranched polyglycerols (HPGs) and their derivatives are widely regarded as promising biomaterials in a variety of diagnostic and therapeutic applications through solubilization, microencapsulation or conjugation with diagnostic agents, drugs, genetic materials, proteins, peptides, etc. HPGs have good chemical stability, inertness under biological conditions, water-solubility with low viscosity and multi-functionalization, which prompt their application as ideal or interesting nanocarriers or modifying agents. Herein, it was aimed to review recent developments and targeted approaches in utilizing HPGs for delivery of drugs, proteins and nucleic acids, as well as tissue engineering, diagnostic and theranostic applications.

Delivery and Anti-Psoriatic Effect of Silibinin-Loaded Polymeric Micelles: An Experimental Study in the Psoriatic Skin Model.

OBJECTIVE: Psoriasis is an inflamed skin disorder associated with the activation of phosphorylation signals in keratinocytes, which leads to proliferation. Phosphorylation signal inhibitors, such as silibinin can inhibit cell proliferation. Unlike current psoriasis treatment approaches that are associated with dangerous side effects; natural components can introduce new trends in psoriasis treatment. The major problem in the topical treatment of psoriasis is drug localization through the psoriasis lesions. METHODS: In this study, silibinin-loaded polymeric micelles prepared and characterized for drug loading and release and ex vivo permeation through psoriatic and normal mice skin. The optimized batch was used for the treatment of psoriasis lesions in the mice model. RESULTS: The optimized batch demonstrated mean particle size 18.3 ± 2.1 nm, entrapment efficiency 75.8 ± 5.8%, and prolonged silibinin release. % Silibinin permeated through psoriatic skin after 48 treated by polymeric micelle and aqueous control was 80.35, and 92.6, respectively. Polymeric micelles increased silibinin localization in the psoriatic skin in comparison with control. In psoriatic skin after 7- 10 days treatment by silibinin- loaded polymeric micelle, there was no evidence of psoriasis and the histological evaluation showed no sign of psoriasis. Silibinin-loaded polymeric micelles reduced Psoriasis area index by more than 78% after 14 days. CONCLUSION: It seems that polymeric micelles increased the effectiveness of silibinin by drug localization into the psoriatic plaque. Topical STAT- 3inhibitors can be introduced as a new strategy in psoriasis treatment.

Reversing multi-drug tumor resistance to Paclitaxel by well-defined pH-sensitive amphiphilic polypeptide block copolymers via induction of lysosomal membrane permeabilization.

A series of hybrid di-block copolymers of poly(l- glutamic acid-b-l- leucine) (PGA-PLeu), methoxy poly (ethylene glycol)-b-poly(l-leucine) (PEG-PLeu), methoxy poly(ethylene glycol)-b-poly(γ-benzyl-l-glutamic acid) (PEG-PBLG) and tri-block copolymers of poly(ethylene glycol)-b-poly(l-glutamic acid-co-null-leucine) (PEG-PGA-PLeu) were synthesized through sequential HMDS-mediated ring-opening polymerization (ROP). Chemical structure of copolymers was studied by FTIR and 1H-NMR and their molecular weight was determined by 1H-NMR and gel permeation chromatography (GPC). Copolymers self-assembled into nanomicelles with particle size (PS) of 65 to 139 nm. Higher fraction of polyleucine (% fPLeu) led to significantly larger PS, lower critical aggregation concentration (CAC) and higher drug loading content (DLC%). In addition, introducing PEG segment led to significant decrease in PS, increase of CAC and DLC%. Apart from copolymer composition, DLC% changed by the method with significantly higher loading for solid dispersion. Remarkably, the release of PTX from PEG-PGA-PLeu tri-block copolymers was highly dependent on pH, revealing a relatively two-fold faster release at pH 5 than pH 7.4. CD spectroscopy showed transition to α-helix secondary structure at acidic pH. Hemocompatibility assay confirmed that copolymers were absolutely hemocompatible at physiological pH. MTT assays demonstrated that unlike MCF7 and 4T1 cells that PTX-loaded nanoparticles (PTX-NPs) exhibited similar antitumor activity, ten-fold higher toxicity was recognized in multidrug-resistant uterine sarcoma cells (MES-SA/DX5). Fluorescent imaging and flow cytometric analysis of cellular uptake showed that nanoparticles' uptake was time-dependent. It was also revealed that higher toxicity of the PTX-NPs could be due to ability of copolymer to inhibit P-gp pumps and induce lysosomal membrane permeabilization (LMP).

Generation and characterization of a specific single-chain antibody against DSPP as a prostate cancer biomarker: Involvement of bioinformatics-based design of novel epitopes.

Isolation of specific single chain antibodies (scFvs) against key epitopes of cancer markers are applied for cancer immunotherapy and diagnosis. In this study following the prediction of the 3D structure of the DSP part of Dentin sialophosphoprotein (DSPP), the epitope was chosen using in silico programs. Panning process was applied to isolate specific human scFv against the epitope. PCR and DNA fingerprinting differentiated the specific clones, which were evaluated by phage ELISA. Following DNA sequencing, the 3D structure of isolated scFv was modeled and Docked on DSP. Results demonstrated the selection of a specific anti-DSPP scFv with 40% frequency, which reacted significantly with the predicted epitope and PCa patients' urines in ELISA tests (P-value < 0.05). The VH and VL of the isolated scFv were from VH1 and VL3 gene families with several amino acid changes in CDRs and FRs domains. The scFv tightly bound to the DSP epitope with the lowest energy level by hydrogen bonds, cation-pi, hydrophobic and ionic interactions demonstrating the specificity of Ag-Ab interactions. The anti-DSPP scFv selected in this study with significant specificity to DSPP antigen offers a promising new agent for both PCa early detection and treatment of cancers with DSPP expression.

Modulated cellular delivery of anti-VEGF siRNA (bevasiranib) by incorporating supramolecular assemblies of hydrophobically modified polyamidoamine dendrimer in stealth liposomes.

A novel lipopolymer based system was designed and characterized for cellular delivery of anti-VEGF siRNA in SKBR-3 breast tumor cell line. Polyamidoamine (PAMAM) dendrimers of low generations (G1, G2 and G3) were incorporated into polyethylene glycol (PEG)-stabilized liposomes by following the consecutive steps: (a) synthesis of the cholesterol conjugates (40% molar ratio of cholesterol to primary amines of PAMAM), (b) incorporation of the conjugates in liposome by lipid mixing and (c) microencapsulation of the siRNA using the ethanol drop method. The cholesterol conjugates of PAMAM dendrimers (G1-Chol40%, G2-Chol40% and G3-Chol40%) formed self assembly with low CMC values (<11µg/ml). Not only did G2-Chol40% show the highest lipid mixing among the cholesterol conjugates, but also, had the lowest leakage of encapsulated carboxyfluorescein tracer. Various N(amine))/L(lipid)/P(phosphate) mole ratios were investigated for siRNA condensation by ethidium bromide dye exclusion assay. The optimum N/L/P ratio of 20:33:10 was chosen for microencapsulation of anti-VEGF siRNA by ethanol drop method, showing particle size of 130nm, zeta-potential of +4mV, siRNA loading efficiency and capacity of 96% and 13wt%, and high stability against heparin sulfate (extracellular matrix). TEM shows uniform and discrete oligo- or multi-lamellar vesicular structures. The liposome incorporating G2-Chol40% was successfully internalized into SKBR-3 cells mainly through clathrin-mediated endocytosis, which was able to escape from endosomes and showed a significantly higher sequence-specific inhibition of VEGF expression and cell growth than the respective G2-Chol40%/siRNA dendriplexes. Importantly, the cytotoxicity decreased with incorporation of G2-Chol40% in the liposomes.

Chemically crosslinked nanogels of PEGylated poly ethyleneimine (l-histidine substituted) synthesized via metal ion coordinated self-assembly for delivery of methotrexate: Cytocompatibility, cellular delivery and antitumor activity in resistant cells.

Self-assembled nanogels were engineered by forming Zn(2+)-coordinated micellar templates of PEGylated poly ethyleneimine (PEG-g-PEI), chemical crosslinking and subsequent removal of the metal ion. Creation of stable micellar templates is a crucial step for preparing the nanogels. To this aim, imidazole moieties were introduced to the polymer by Fmoc-l-histidine using carbodiimide chemistry. It was hypothesized the nanogels loaded with methotrexate (MTX), a chemotherapeutic agent, circumvent impaired carrier activity in HepG2 cells (MTX-resistant hepatocellular carcinoma). So, the nanogels were post-loaded with MTX and characterized by (1)H-NMR, FTIR, dynamic light scattering-zeta potential, atomic force microscopy, and drug release experiments. Cellular uptake and the antitumor activity of MTX-loaded nanogels were investigated by flow cytometry and MTT assay. Discrete, spherical and uniform nanogels, with sizes about 77-83 nm and a relatively high drug loading (54 ± 4% w/w), showed a low polydispersity and neutral surface charges. The MTX-loaded nanogels, unlike empty nanogels, lowered viability of HepG2 cells; the nanogels demonstrated cell-cycle arrest and apoptosis comparably higher than MTX as free drug that was shown to be through i) cellular uptake of the nanogels by clathrin-mediated transport and ii) endosomolytic activity of the nanogels in HepG2 cells. These findings indicate the potential antitumor application of this preparation, which has to be investigated in-vivo.

A histological comparison of a new pulp capping material and mineral trioxide aggregate in rat molars.

INTRODUCTION: Recent investigations have attempted to improve regenerative endodontics with the help of stem cell therapy. In vitro studies have shown the ability of different agents to stimulate the differentiation of dental pulp stem cells (DPSC) into odontoblast-like cells. A combination of dexamethasone, ß-glycerophosphate and Vitamin D has been proven to induce a successful differentiation. The aim of this animal study was to evaluate the effect of this combination, named odontoblastic differentiating material (ODM), on pulp tissue when used as a capping material. MATERIALS AND METHODS: Sixty maxillary right and left molars of 30 Sprague-dawley rats were selected for this study. The teeth were exposed under sterile condition. Half of the teeth were capped with mineral trioxide aggregate (MTA) and the other half with ODM. All cavities were restored with glass ionomer. The rats were sacrificed at post-operative intervals of 2 weeks and 2 months. Samples were histologically evaluated for the degree of inflammation and reparative dentin formation. Finally the data was analyzed with Mann-Whitney and Chi-Square tests. RESULTS: Reparative dentin formed in all groups within both time periods and there was no statistically significant difference between the groups in the mentioned time periods. The MTA group, however, showed a statistically significant reduction in inflammation at both time intervals (P<0.05). Compared to MTA, ODM samples showed a greater amount of inflammation in the pulp tissue. CONCLUSION: ODM, as a pulp capping material, can induce dentinal bridge formation.