Preparation of a capsaicin-loaded nanoemulsion for improving skin penetration.

Capsaicin o/w nanoemulsions with enhanced skin permeation were successfully prepared by controlling the ratios of the surfactant mixtures, oleoresin capsicum as the oil phase, and aqueous phase. Oleoresin capsicum contains 22.67 mg/g of capsaicin, which is an active and oil-soluble ingredient. Nonionic surfactants, Tween 80 and Span 80, were used to optimize the weight ratio of surfactant mixtures (85.98:14.02) by calculating the hydrophile-lipophile balance (HLB) value. The optimal processing conditions for stable nanoemulsions were investigated by using a ternary phase diagram. The mean droplet size of nanoemulsions ranged from 20 to 62 nm. Skin permeation studies were performed using a Franz diffusion cell. The permeation profiles and confocal laser scanning microscopy (CLSM) images supported that capsaicin nanoemulsion could well permeate all skin layers from the stratum corneum to the dermis. The selected nanoemulsions showed great potential as transdermal delivery carriers for enhancing the permeation of core materials.

Oleoyl-chitosan nanoparticles inhibits Escherichia coli and Staphylococcus aureus by damaging the cell membrane and putative binding to extracellular or intracellular targets.

A novel chitosan antibacterial dispersion system was prepared by oleoyl-chitosan (OCS) nanoparticles (OCNP). We further investigated the antimicrobial mode of OCNP against Escherichia coli and Staphylococcus aureus using a combination of approaches, including measurement of the effect of lecithin and phosphate groups, the conformation of membrane protein, internalization of fluorescein isothiocyanate (FITC)-labeled OCS nanoparticles (FITC-OCS nanoparticles) observed under fluorescence microscopy and DNA/RNA binding assay. Results of fluorescence experiments indicated that OCNP influenced the structure of bacterial membranes. The lecithin effect showed that OCNP bound to cytoplasmic membrane phospholipids of S. aureus, and phosphate groups played an important role. Fluorescence microscopy observations demonstrated that the way OCNP entered into bacteria varied against strains. The gel-retardation experiment showed that OCNP bound strongly to DNA/RNA and retarded their migration in the gels in a concentration-dependent manner. These results indicate that OCNP exerts its antibacterial activity by damaging the structures of cell membrane and putative binding to extracellular targets such as phosphate groups or intracellular targets such as DNA and RNA.

Microencapsulation of a probiotic bacteria with alginate-gelatin and its properties.

Lactobacillus casei ATCC 393-loaded microcapsules based on alginate and gelatin had been prepared by extrusion method and the product could increase the cell numbers of L. casei ATCC 393 to be 10(7) CFU g(-1) in the dry state of microcapsules. The microparticles homogeneously distributed with size of 1.1 ± 0.2 mm. Four kinds of microcapsules (S(1), S(2), S(3) and S(4)) exhibited swelling in simulated gastric fluid (SGF) while the beads eroded and disintegrated rapidly in simulated intestinal fluid (SIF). Cells of L. casei ATCC 393 could be continuously released from the microcapsules during simulated gastrointestinal tract (GIT) and the release amounts and speeds in SIF were much higher and faster than that in SGF. Encapsulation in alginate-gelatin microcapsules successfully improved the survival of L. casei ATCC 393 and this approach might be useful in delivery of probiotic cultures as a functional food.

Optical diagnosis of cervical intraepithelial neoplasm (CIN) using polarization-sensitive optical coherence tomography.

We present a polarization-sensitive optical coherence tomography (PS-OCT) technique that can quantify the polarization changes (the degrees of circular polarization, DOCP) caused by the scattering changes induced by cervical intraepithelial neoplasia (CIN). The axial and lateral resolutions of our PS-OCT system are 13 microm and 15 microm, respectively. Uterine cervical conization tissue samples from 18 patients were examined, and 71 areas were imaged for in vitro studies; about 2-4 areas per sample were imaged and processed for diagnosis. The scanned areas had a size of 2 mm (axial) X 2 mm (lateral) X 4 mm (transversal). We quantified the slope of the axial decay of the DOCP signal near the cervical epithelium by a linear fitting procedure. The excised samples were then investigated by two pathologists, and their histological findings were later compared with the PS-OCT results. Our results show that the sensitivity and specificity are 94.7% and 71.2%, respectively.

Effect of the molecular mass and degree of substitution of oleoylchitosan on the structure, rheological properties, and formation of nanoparticles.

Oleoylchitosans (O-chitosans), with different molecular masses and degrees of substitution (DS), were synthesized by reacting chitosan with oleoyl chloride. The FT-IR suggested the formation of an amide linkage between amino groups of chitosan and carboxyl groups of oleic acid. The viscosity of O-chitosan sharply increased with the increase of concentration, whereas that of unmodified chitosan rose only slightly. This increase was stronger as the increase of hydrophobicity (DS) and molecular mass of the polymer. The critical aggregation concentration (CAC) of O-chitosans with DS 5, 11, and 27% were 79.43, 31.6, 10 mg/L, respectively, and the CAC of samples with molecular masses of 20, 38, 300, and 1100 kDa were 50.1, 74.93, 125.9, and 630.9 mg/L, respectively. All of the O-chitosans could reduce surface tension slightly. Nanoparticles were prepared using an O/W emulsification method. Mean diameters of the polymeric amphiphilic nanoparticles of O-chitosans with DS 5 and 11% were around 327.4 and 275.3 nm, respectively.

Biopolymer-based antimicrobial packaging: a review.

The term antimicrobialpackaging encompasses any packaging technique(s) used to control microbial growth in a food product. These include packaging materials and edible films and coatings that contain antimicrobial agents and also techniques that modify the atmosphere within the package. In recent years, antimicrobial packaging has attracted much attention from the food industry because of the increase in consumer demand for minimally processed, preservative-free products. Reflecting this demand, the preservative agents must be applied to packaging in such away that only low levels of preservatives come into contact with the food. The film or coating technique is considered to be more effective, although more complicated to apply. New antimicrobial packaging materials are continually being developed. Many of them exploit natural agents to control common food-borne microorganisms. Current trends suggest that, in due course, packaging will generally incorporate antimicrobial agents, and the sealing systems will continue to improve. The focus of packaging in the past has been on the appearance, size, and integrity of the package. A greater emphasis on safety features associated with the addition of antimicrobial agents is perhaps the next area for development in packaging technology.