Simple Gel Research Articles

Comparative study of photocatalysis and gas sensing of ZnO/Ag nanocomposites synthesized by one- and two-step polymer-network gel processes

Abstract Catalytic and sensing performance of ZnO/Ag nanocomposites greatly depends on the synthesis method used for its production, presenting both challenges and opportunities for optimization. A polymer-network gel process is one of the promising techniques that enables cheap and efficient synthesis of photoactive ZnO/Ag nanocomposites. However, the mechanisms responsible for the formation of ZnO/Ag interfaces are not completely understood, and the photocatalytic efficiency of the ZnO/Ag nanocomposites produced by a simple gel process is not sufficient. In this paper we describe a comparative study on the one- and two-step polymer network gel synthesis techniques, and investigate the mechanisms that account for the significant differences in the observed performance of ZnO/Ag produced by these two methods. The ZnO/Ag nanocomposites synthesized by the two-step method exhibit remarkably enhanced photocatalytic efficiency for Methylene blue, Methyl orange, Rhodamine B, Malachite Green and Formaldehyde (HCHO) under UV light irradiation and simulated sunlight. As the gas sensing material, the ZnO/Ag nanocomposites synthesized by the two-step method show the higher sensitivity and better stability and selectivity. The microstructures and optical characteristics of the samples were revealed by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, ultraviolet visible (UV–vis) spectroscopy, room temperature photoluminescence measurements, and energy dispersive X-ray (EDS) analysis. Samples synthesized by the two-step process possess a more uniform dispersion of Ag nanoparticles, a smaller Ag crystallite size, and a narrower bandgap. Chemically, more oxygen vacancies and hydroxyl radicals are present in the samples synthesized by the two-step process. Jointly, these factors favor enhanced photocatalytic degradation of organic pollutants, and sensitivities of the sensors.

Growth of Copper Iodate Crystal in Gel and its Characterisations

Copper iodate crystals are grown using simple gel technique at ambient temperature. The various lattice parameters of grown crystals are obtained , gel aging time ,gel setting time ,Effect of pH observed, Different characterisation like X-ray Diffraction h,k,l values are determined, FTIR spectroscopic Analysis and Thermal behaviour of grown crystal like Thermogravimetric Analysis TGA are Discussed .Effect of Doping, Molar concentrations, PH of reactants and Alternate Diffusion methods in gel for size of crystal studied

Bioinspired Thermoresponsive Xyloglucan–Cellulose Nanocrystal Hydrogels

Thermoresponsive hydrogels present unique properties, such as tunable mechanical performance or changes in volume, which make them attractive for applications including wound healing dressings, drug delivery vehicles, and implants, among others. This work reports the implementation of bioinspired thermoresponsive hydrogels composed of xyloglucan (XG) and cellulose nanocrystals (CNCs). Starting from tamarind seed XG (XGt), thermoresponsive XG was obtained by enzymatic degalactosylation (DG-XG), which reduced the galactose residue content by ∼50% and imparted a reversible thermal transition. XG with native composition and comparable molar mass to DG-XG was produced by an ultrasonication treatment (XGu) for a direct comparison of behavior. The hydrogels were prepared by simple mixing of DG-XG or XGu with CNCs in water. Phase diagrams were established to identify the ratios of DG-XG or XGu to CNCs that yielded a viscous liquid, a phase-separated mixture, a simple gel, or a thermoresponsive gel. Gelation occurred at a DG-XG or XGu to CNC ratio higher than that needed for the full surface coverage of CNCs and required relatively high overall concentrations of both components (tested concentrations up to 20 g/L XG and 30 g/L CNCs). This is likely a result of the increase in effective hydrodynamic volume of CNCs due to the formation of XG-CNC complexes. Investigation of the adsorption behavior indicated that DG-XG formed a more rigid layer on CNCs compared to XGu. Rheological properties of the hydrogels were characterized, and a reversible thermal transition was found for DG-XG/CNC gels at 35 °C. This thermoresponsive behavior provides opportunities to apply this system widely, especially in the biomedical field, where the mechanical properties could be further tuned by adjusting the CNC content.

Bimodal size distribution immuno-quantum dots for fluorescent western blotting assay with high sensitivity and extended dynamic range.

A highly sensitive quantum dot (QD)-based western blot assay with extended dynamic range was developed. Bimodal size distribution QD (BQ) immunoprobes composed of small size single QD (7.3 nm) and big size QD nanobead (QB) (82.9nm) were employed for fluorescent western blot immunoassay on a membrane. Small size QD immunoprobes contributed to wider dynamic range of assay, while big size QB immunoprobes provided higher detection sensitivity. This BQ-based western blot assay can achieve a wide dynamic range (from 7.8 to 4000ng IgG) and is nearly as sensitive as commercial available ultrasensitive chemiluminescent methods, just using a simple gel imager with UV light (365nm) excitation and red light filter (610nm). The fluorescent signals of BQ western blot were stable for 10 min, while chemiluminescent signals faded after 1min. Moreover, this BQ immunoprobe was utilized for the detection of housekeeping protein and specific target proteins in complex cell lysate samples. The limit of detection of housekeeping protein is 0.25μg of cell lysate, and the signal intensities were proportional to loading protein amount in a wide range from 0.61 to 80μg. We believe that this new strategy of bimodal size distribution nanoparticles can also be expanded for other functional nanoparticle-based biological assays to improve the sensitivity and extend the dynamic range. Graphical abstract.

Two-Dimensional Visualization and Quantification of Labile, Inorganic Plant Nutrients and Contaminants in Soil.

We describe a method for two-dimensional (2D) visualization and quantification of the distribution of labile (i.e., reversibly adsorbed) inorganic nutrient (e.g., P, Fe, Mn) and contaminant (e.g., As, Cd, Pb) solute species in the soil adjacent to plant roots (the 'rhizosphere') at sub-millimeter (~100 µm) spatial resolution. The method combines sink-based solute sampling by the diffusive gradients in thin films (DGT) technique with spatially resolved chemical analysis by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The DGT technique is based on thin hydrogels with homogeneously distributed analyte-selective binding phases. The variety of available binding phases allows for the preparation of different DGT gel types following simple gel fabrication procedures. For DGT gel deployment in the rhizosphere, plants are grown in flat, transparent growth containers (rhizotrons), which enable minimal invasive access to a soil-grown root system. After a pre-growth period, DGT gels are applied to selected regions of interest for in situ solute sampling in the rhizosphere. Afterwards, DGT gels are retrieved and prepared for subsequent chemical analysis of the bound solutes using LA-ICP-MS line-scan imaging. Application of internal normalization using 13C and external calibration using matrix-matched gel standards further allows for the quantification of the 2D solute fluxes. This method is unique in its capability to generate quantitative, sub-mm scale 2D images of multi-element solute fluxes in soil-plant environments, exceeding the achievable spatial resolution of other methods for measuring solute gradients in the rhizosphere substantially. We present the application and evaluation of the method for imaging multiple cationic and anionic solute species in the rhizosphere of terrestrial plants and highlight the possibility of combining this method with complementary solute imaging techniques.

Curcumin Niosomes (curcusomes) as an alternative to conventional vehicles: A potential for efficient dermal delivery

This research aimed to enhance the skin delivery of curcumin niosome (curcusome) made by a thin film hydration technique. To optimize the cucusome formulations the effect of the ratio of cholesterol:surfactants was investigated. The solid-state and morphology of curcumin in curcusome was characterized by photon correlation spectroscopy, powder x-ray diffractometer (PXRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The results showed that the particle size of curcusomes decreased by adding cholesterol. The results showed that the size and zeta potential of nanoparticles can be modulated by the changes in cholesterol and surfactant concentrations. Zeta potential data showed an increase in this value from −0.73 ± 0.31 to −9.31 ± 0.97 mV when the concentration of cholesterol declined from 1.8 to 0%. Maximum entrapment efficiency around 95% was observed for a formulation with the greatest content of cholesterol. Solid-state analysis results ruled out any interaction between excipients and curcumin, and also showed that curcumin was in an amorphous state in the niosomes. Skin permeation test showed that the amounts of the curcumin in skin layers and the receptor chamber was greater for curcusome than when the curcumin solution was used. The skin irritation test of the formulations on Wistar rats showed that the curcumin niosomal gels were not irritant. Finally, curcusome formulations revealed considerable antinociceptive and anti-inflammatory activities compared to the control group in the late phase. The utilizations of the curcusome gel modified the tail-flick latency as compared to the curcumin simple gel, placebo, as well as the simple gel (P < 0.05). These results suggested that nisomes could enhance the efficiency of curcumin as an antinociceptive and anti-inflammatory agent via improvement in drug delivery to the target location.

Isotachophoresis-Enhanced Immunoassays: Challenges and opportunities

Protein detection and quantification is a crucial part of many clinical, research, and preparatory applications [1]. Protein biomarkers, such as prostate-specific antigen (PSA) [2] and carcinoembryonic antigen (CEA), are regularly detected and quantified for cancer diagnosis and treatment monitoring [3]. On the other hand, cardiac troponin 1 (CTn1) is the most important protein to quantify to detect cardiac injury and myocardial infarction [4]. The detection of protein biomarkers such as PSA, CEA, and CTn1 requires specific identification and quantification of the protein, eliminating detection techniques that enable only size-based quantification of proteins in general, such as silver staining and simple gel electrophoresis [5].

Gel electromembrane extraction: Study of various gel types and compositions toward diminishing the electroendosmosis flow

For the first time, the effect of electroendosmosis (EEO) flow phenomenon was investigated in detail, on the gel electromembrane extraction (G-EME). When electric field is used as an actuator of ion transport in G-EME, the EEO flow phenomenon can occur within the agarose gel membrane interface and is generally considered the dominant issue. In this regard, various agarose-based gel membrane types with low-, medium- and high-EEO were fabricated and tested. To further diminish the EEO effect, the different gel membrane additives such as dextrin, chitosan and xylan with different concentrations i.e., 5%, 10% and 15% were also examined. The positively charged Cr(III) and negatively charged Cr(VI) were chosen as model analytes. The Cr(III) and Cr(VI) were simultaneously extracted from an aqueous sample (pH 3.0) via the cathodic and anodic gel membranes (pH 3.0 for both membranes), into the cathodic and anodic aqueous acceptors (200 µL each, pH 2.0), respectively. After extraction at the optimal conditions (i.e., voltage: 32 V, extraction time: 22 min), the both compounds were quantified by a cheap and easy-to-perform reader platform termed as microfluidic paper-based analytical device (μPAD). The results showed that high extraction recoveries such as 87% for Cr(III) and 75% for Cr(VI), were acquired when the low-EEO agarose gel membrane with 5% (w/v) dextrin was used. On the other hand, using the high-EEO agarose gel membrane with no additive lead to the high EEO flow and the increase of cathodic acceptor volume (equal to 350 µL) while the recovery depressed to about 50% due to the dilution effect. Simultaneously, the volume of anodic acceptor became almost vacant (~50 µL). Ultimately, by means of such simple gel membrane adjusting (i.e., low-EEO agarose with 5% dextrin), the both target compounds were quantitatively extracted at a single step achieving limits of detection (LODs) of 0.5 and 0.7 ng mL−1 for Cr(III) and Cr(VI), respectively.

Development of a Novel Simple Gel Formulation Containing an Ion-Pair Complex of Diclofenac and Phenylephrine

Background and Aim: Since the pharmacological effects of diclofenac (DF) are short-lived because of its short half-life, prolongation of the pharmacological effect in a topical formulation is needed for more appropriate clinical use. For the enhancement of dermal accumulation and prolongation of the pharmacological effect of drugs, the aim of this study was to develop a simple gel formulation containing an ion-pair complex of DF and phenylephrine (PHE), which induce constriction of the vascular smooth muscles. Materials and Methods: The ion-pair complex was prepared by mixing sodium DF and an ethanolic solution of PHE. The formed complex was characterized by powder X-ray diffraction (PXRD) and Fourier-transform infrared (FT-IR) spectroscopy. The ion-pair complex for the gel formulation was prepared by mixing an equimolar concentration of 50% 1,3-butylene glycol and distilled aqueous solution of 2% xanthan gum, which was characterized by proton nuclear magnetic resonance (¹H-NMR). Skin permeation and accumulation of DF and PHE were evaluated by in vitro and in vivo studies. Results: From the results of PXRD and FT-IR, it was suggested that new crystalline peaks formed by the ion-pair complex and their complex interacted with the carboxyl group in DF and the amino group in PHE. In the gel formulation, the ion-pair complexes were detected by ¹H-NMR. The ion-pair complex enhanced the accumulation of DF in the skin in the in vitro study. On the other hand, PHE accumulation in the dermis increased with the ion-pair complex, as exhibited by the in vivo study. Conclusion: A new gel formulation containing the ion-pair complex of DF and PHE was developed, which improved the accumulation of DF in skin.

Newborn Screening With Sickle Cell Point of Care: A Valuable Resource in Low-Income Settings.

* Abbreviations: HbF — : fetal hemoglobin HbS — : sickle hemoglobin IEF — : isoelectric focusing POC — : point of care SCD — : sickle cell disease The first description of newborn screening was published in Pediatrics >50 years ago1 and ushered in an era of opportunity to identify infants with underlying medical conditions before they developed signs and symptoms of disease. Although the index medical condition was phenylketonuria, Robert Guthrie (developer of this system and originator of the eponymous Guthrie card) recognized that sickle cell disease (SCD) was also well suited to neonatal screening using dried blood spots2 because normal adult hemoglobin could be separated by simple gel electrophoresis from both abnormal sickle hemoglobin (HbS) and fetal hemoglobin (HbF). The technical aspects of hemoglobin separation have improved over the years with the advent of high-performance liquid chromatography and isoelectric focusing (IEF), but newborn screening for SCD has essentially remained the same as it was originally envisioned. The United States now enjoys universal screening for SCD and other inherited hemoglobin disorders, and >2000 affected infants are identified annually.3 Despite these successes in the United States and other high-income countries, standard sickle cell screening techniques do not lend themselves well to low-resource settings. In many low-income countries, infants are often born … Address correspondence to Russell E. Ware, MD, PhD, Department of Pediatrics, Cincinnati Children’s Hospital, 3333 Burnet Ave, Cincinnati, OH 45229. E-mail: russell.ware{at}cchmc.org

Long-Term Bone Regeneration Enabled by a Polyhedral Oligomeric Silsesquioxane (POSS)-Enhanced Biodegradable Hydrogel

The development of artificial bone substitutes mimicking the extracellular matrix is a promising strategy for bone repair and regeneration. However, the preparation of materials tailored to feature sufficient mechanical properties, appropriate degradation rates, and favorable osteoinductivity continues to be a great challenge. Hydrogels from biopolymers have emerged as viable substitutes in bone regeneration, but they often suffer from insufficient mechanical strength and rapid degradation rate, critically limiting their clinical applicability. Here, we demonstrate that inorganic/biopolymer hybrid hydrogels formed through photo-cross-linking of methacrylated gelatin (Gel) and octamethacrylated polyhedral oligomeric silsesquioxane (OMAPOSS) nanocages can be tailored to possess high mechanical strength, more appropriate degradation rate, and provide biological activity to meet tissue growth demands outperforming simple Gel hydrogels without POSS. Moreover, Gel-POSS hybrid hydrogels effectively promote mesenchymal stem cell (MSC) attachment, spreading, and proliferation, and, critically enhance the osteogenesis of MSCs as evidenced by improved bone repair in a rat calvarial defect model. Hence, such POSS-enhanced synthetically tailored hybrid hydrogels represent a promising concept for long-term bone tissue regeneration.

SIMPLE METHOD FOR OPTIMIZATION OF HEPARIN AND ENOXAPARIN DETECTION USING AGAROSE GEL ELECTROPHORESIS

Objective: A simple gel electrophoresis method for low-molecular-weight heparins (LMWH) is required for use in a variety of laboratories to allow further identification and purification. This study aimed to optimize the detection of heparin and enoxaparin (low-molecular-weight heparin by gel electrophoresis.&#x0D; Methods: Several gel electrophoresis conditions were tested to optimize the detection of enoxaparin by using a simple method with a modified Volpi’s approach. Multiple gel thicknesses, voltage settings, and enoxaparin concentrations were tested in the optimization procedure. Enoxaparin was purchased from a local supplier as pre-filled pharmaceutical injections. Highly purified 0.5% and 1.0% agarose gels were prepared and a series of enoxaparin concentrations was added to both gels for comparison and optimization. The 0.2% toluidine blue stain was prepared by the addition of 1 ml in an ethanol-water-acetic acid mixture (50:49:1; v/v/w). The staining process comprised two steps: first, toluidine blue was added for 30 min and destained overnight in the solvent mixture. Subsequently, the following morning, the second step was conducted, in which the gel was restained for 30 min with the same concentration of toluidine blue. We continued to stain the gel until the bands were visible.&#x0D; Results: The gel electrophoresis results showed that clearest and sharpest bands were obtained using 65–75 mAh and 85 V settings. At 95 mAh, the bands were slightly washed out.&#x0D; Conclusion: This study successfully facilitated the detection of enoxaparin, a LMWH, and heparin in the laboratory by using simple tools and techniques available in most laboratories.

Characterization of storage stability of resol resin solutions via gel time measurement and high-performance liquid chromatography

The influence of the temperature of storage on the proceeding polycondensationof commercial resol resin solutions was analyzed and it was found that results derived from a simple gel time measurements can provide the necessary information. It could be shown that resol resin solutions can be fitted into Arrhenius like models, which allow an extrapolation of the temperature-dependent changes of the material over arbitrary temperature ranges and hence estimation of the prolongation or reduction of declared shelf-life. High-performance liquid chromatographic analyses of the content of free phenol and free formaldehyde during storage could confirm and widely explain the observations from gel time measurements.

Development of emulgel formulation for vaginal candidiasis: Pharmaceutical characterization, in vitro and in vivo evaluation

The aim of the investigation was to develop nanoemulsion (NE) based emulgel of Mentha essential oil (MEO: potent antifungal property) to ensure enriched and extended therapeutic effectiveness against various species of Candida and vaginal candidiasis. NE was prepared and optimized using central composite design. pH-triggered crosslinking of NE in carbopol 940 matrix (emulgel) was achieved by triethanolamine. Emulgel was evaluated for in vitro (against Candida spp.) and in vivo (efficacy in Swiss albino female mice infected by installing 4 × 107 cfu/ml of Candida albicans) activity against the standard control and simple gel of MEO. NE droplets were observed to be spherical and uniform in size (178.087 ± 0.834 nm). Zeta potential and polydispersibility index (PDI) were measured using a diffraction light scattering technique and was found to be 31.56 ± 1.987 mV and 0.176, respectively. Emulgel demonstrated a significantly broader zone of growth inhibition than simple gel (gel of coarse emulsion) when studied against Candida spp. In vivo colony counts of C. albicans in the case of emulgel were observed to be significantly lesser in number (165 cfu/ml) than simple gel (380 cfu/ml). Texture and viscosity of emulgel were measured using a texture analyser and Brookfield viscometer, respectively and were found to be reasonably acceptable for mucosal administration. Texture parameters of emulgel were consistent over 90 days (prolonged stability). Encapsulation of MEO in NE followed by crosslinking in cellulosic polymer ensures reduced volatility and improved effectiveness against candidiasis like condition.

Supramolecular Synthon Approach in Designing Molecular Gels for Advanced Therapeutics

AbstractLow‐molecular‐weight gelators (LMWGs) are an important class of soft materials that offer various potential applications including drug delivery. Structural diversities of the reported LMWGs and lack of molecular‐level understanding of the self‐assembly process of gelation make it difficult to design a gelator a priori. Most often gelators are discovered in a serendipitous manner and second‐generation gelators are designed by modifying known gelling scaffolds. Since gel network within which the solvent molecules are immobilized is often found to be crystalline, a supramolecular synthon approach in the context of crystal engineering is demonstrated to be quite effective in designing LMWGs for various applications including therapeutics. Self‐drug‐delivery systems, wherein the need for a delivery vehicle does not exist, are becoming an effective alternative to conventional drug delivery systems. In the form of a simple gel (for non‐invasive topical application) or injectable gel (for invasive subcutaneous applications), LMWGs derived from drugs provide an effective way to develop self‐drug‐delivery systems. This review article encompasses the early development of LMWG research, describes gradual transition from discovering just a gelator to a gelator having potential material applications including drug delivery, and highlights the merit of supramolecular synthon approach in designing LMWGs for self‐drug‐delivery applications.

Simple and rapid system for two-dimensional gel electrophoresis technique: A laboratory exercise for high school students.

Polyacrylamide gel electrophoresis (PAGE) is the most classical technique favored worldwide for resolution of macromolecules in many biochemistry laboratories due to its incessant advanced developments and wide modifications. These ever-growing advancements in the basic laboratory equipments lead to emergence of many expensive, complex, and tricky laboratory equipments. Practical courses of biochemistry at high school or undergraduate levels are often affected by these complications. Two dimensional gel electrophoresis technique (2D-PAGE) used for resolving thousands of proteins in a gel is a combination of isoelectric focusing (first dimension gel electrophoresis technique) and sodium-dodecylsulphate PAGE (second dimension gel electrophoresis technique or SDS-PAGE). Two different laboratory equipments are needed to carry out effective 2D-PAGE technique, which also invites extra burden to the school laboratory. Here, we describe a low cost, time saving and simple gel cassette for protein 2D-PAGE technique that uses easily fabricated components and routine off-the-shelf materials. The performance of the apparatus was verified in a practical exercise by a group of high school students with positive outcomes. © 2018 by The International Union of Biochemistry and Molecular Biology, 46(3):237-244, 2018.

Microwave absorption properties of reduced graphene oxide strontium hexaferrite/poly(methyl methacrylate) composites

The key factors to consider when designing microwave absorber materials for eradication of electromagnetic (EM) pollution are absorption of incident EM waves and good impedance matching. By keeping these things in mind, flexible microwave absorber composite films can be fabricated by simple gel casting techniques using reduced graphene oxide (RGO) and strontium ferrite (SF) in a poly(methyl methacrylate) (PMMA) matrix. SF nanoparticles are synthesized by the well known sol–gel method. Subsequently, reduced graphene oxide (RGO) and SF nanocomposite (RGOSF) are prepared through a chemical reduction method using hydrazine. The structure, morphology, chemical composition, thermal stability and magnetic properties of the nanocomposite are characterized in detail by various techniques. The SF particles are found to be nearly 500 nm and decorated on RGO sheets as revealed by field emission scanning electron microscopy and transmission electron microscopy analysis. Fourier transform infrared and and Raman spectroscopy clearly show the presence of SF in the graphene sheet by the lower peak positions. Finally, ternary polymer composites of RGO/SF/PMMA are prepared by an in situ polymerization method. Magnetic and dielectric studies of the composite reveal that the presence of RGO/SF/PMMA lead to polarization effects contributing to dielectric loss. Also, RGO surrounding SF provides a conductive network in the polymer matrix which is in turn responsible for the magnetic loss in the composite. Thus, the permittivity as well as the permeability of the composite can be controlled by an appropriate combination of RGO and SF in PMMA. More than 99% absorption efficiency is achieved by a suitable combination of magneto-dielectric coupling in the X-band frequency range by incorporating 9 wt% of RGO and 1 wt% of SF in the polymer matrix.

Enhancement of Percutaneous Delivery of Dapsone by Microemulsion Gel

<p style="text-align: justify;"><strong>Objective:</strong> The purpose of this study was to developed microemulsion based gel formulation for topical delivery of dapsone with an objective to increase the solubility and skin permeability of the drug for treatment of acne. <strong>Methodology:</strong> The solubility of dapsone in oils, surfactants and cosurfactants was evaluated by saturation solubility to screen the components of the microemulsion. The pseudoternary phase diagrams were constructed using capryol 90 and N-methyl-2 pyrrolidone as the oil phase, Kolliphor EL as surfactant and PEG 400 as the co-surfactant. The system were assessed for drug-loading efficiency and characterized for pH, conductance, viscosity, particle size, drug content, globule size, zeta potential and drug release. Optimized formulation systems were formulated into gel form by using poloxamer- 407 and evaluated for viscosity, spreadability, drug content, stability, in-vitro skin permeation, steady state flux, permeability coefficient, enhancement ration and skin irritation study. <strong>Result and Discussion:</strong> Globule size of optimized microemulsion (F2) was found to be 27.53 nm, zeta potential was found to be-14.6 mV, permeability of drug from microemulsion within 8h was observed 82%, In- vitro diffusion study showed increase in flux of microemulsion based gel (392.43 &mu;g cm-2 h-1) to that of simple dapsone gel (274.4 &plusmn; 0.78 &mu;g cm-2h-1). Draize test revealed absence of irritation and inflammation on rat skin. <strong>Conclusion:</strong> Microemulsion based gel of dapsone formulation provided better application property and stability in comparison to simple gel. <p style="text-align: justify;"><strong>Key words:</strong> Acne vulgaris, Dapsone, Flux, <em>In-vitro</em> skin permeation, Topical delivery.

Surface-deacetylated chitin nanofibers reinforced with a sulfobutyl ether β-cyclodextrin gel loaded with prednisolone as potential therapy for inflammatory bowel disease

Surface-deacetylated chitin nanofibers (SDACNFs) reinforced with a sulfobutyl ether β-cyclodextrin (SBE-β-CD) (NFs-CDs) gel were developed to obtain a controlled release carrier of prednisolone (PD) for the treatment of colitis. PD was released slowly from the gel at both pH 1.2 and 6.8. The in vitro slow release of PD from the NFs-CDs gel was reflected in the in vivo absorption of the drug after oral administration to rats. These results suggest that a simple gel composed of a mixture of SDACNFs and SBE-β-CD has the potential for use in the controlled release of PD. We also evaluated the therapeutic effects of the NFs-CDs gel containing PD on dextran sulfate sodium (DSS)-induced colitis model mice. The administration of the NFs-CDs gel at intervals of 3days from the beginning of the DSS treatment resulted in a significant improvement, not only in colitis symptoms but also histopathological changes in colon tissue. In addition, the therapeutic effects of the NFs-CDs gel on colitis can be attributed to decreased levels of neutrophil infiltration and the development of oxidative stress. These efficacy profiles of the NFs-CDs gel containing PD suggest that it has the potential for use in the treatment of, not only colitis, but also a variety of other disorders associated with inflammation and oxidative injuries.

Vertical order of DPPC multilayer enhanced by cholesterol-induced ripple-to-liquid ordered (LO) phase transition: Synchrotron X-ray reflectivity study

We investigated the effect of cholesterol on the vertical order of spin-coated supported dipalmitoylphosphatidylcholine (DPPC) multilayers by using synchrotron X-ray reflectivity with customized X-ray liquid cell. As increasing mol% of cholesterol up to 10%, the lamellar spacing of the DPPC multilayer increases, implying that cholesterol induces a tilt-to-untilt transition. The sharpening of X-ray intensity upon cholesterol binding, reflected in the FWHM plot, suggests that cholesterol enhances the vertical ordering of the DPPC multilayer. In addition, fluorescence microscopy experiment confirms a gel-to-liquid ordered (LO) phase transition between 5 and 7% cholesterol. As a result, in low cholesterol regime, the DPPC multilayer is not in a simple gel phase but in a ripple phase where lipids are vertically disordered due to the differently tilted chains which leads to undulations. Therefore, we conclude that the cholesterol-induced ripple-to-LO phase transition enhances the vertical order of the DPPC multilayer. While most of works on membrane structure and cholesterol effect have focused on the physical properties of lipid membrane in lateral direction, this paper suggested a new physical aspect of studying vertical structures of membrane.