Curcumin-embedded DBPC liposomes coated with chitosan layer as a fluorescence nanosensor for the selective detection of ribonucleic acid.

One of the limitations of fluorescence probe molecules during biomedical estimation is their lack of ability to selectively determine the targeted species. To overcome this there have been various approaches that involve attaching a functional group or aptamers to the fluorescence probe. However, encapsulating probe molecules in a matrix using nanotechnology can be a viable and easier method. Curcumin (Cur) as a fluorescence marker cannot distinguish DNA and RNA. This research reports a novel selective approach involving the use of nanocapsules composed of liposomal curcumin coated with chitosan for the selective detection of RNA molecules using a fluorescence method. The increase in RNA concentration enhanced the electrostatic interaction between the negatively charge surface of RNA and the positively charged nanocapsule, which was further verified by zeta potential measurement. This method had a low limit of detection (36 ng/ml) and higher linear dynamic ranges compared with other studies found in the literature. Moreover, the method was not affected by DNA and was selective for the detection of RNA molecules for which the site of interaction was confined only to uracil. The selectivity for RNA molecules towards other analogues species was also examined and recovery range found was between 99 and 100.33%.

Curcumin Modulates 1,2-dibehenoyl-sn-glycero-3-phosphocholine (DBPC) Liposomes: Chitosan Oligosaccharide Lactate Influences Membrane Fluidity But Does Not Alter Phase Transition Temperature of DBPC Liposomes.

1,2-dibehenoyl-sn-glycero-3-phosphocholine (DBPC) is one of the important phospholipids found in cell membrane but not studied well. Importance of curcumin as a dietary supplement and for its medicinal properites is getting widely recoginsed. The present study for the first time explores the effect of curcumin on properties of DBPC liposomes by monitoring the fluorescence properties of curcumin. The phase transition temperature (Tm) of DBPC is assessed which confirms increase in curcumin concentration causes a slight drop in the Tm value. Chitosan is being applied for various drug delivery uses. The study establishes new insight on effect of chitosan oligosaccharide lactate on DBPC liposomes. It is found that in the absence of chitosan oligosaccharide lactate, curcumin partitions more strongly in the liquids crystalline phase than in the solid gel phase, however, the opposite result is obtained with the presence of chitosan oligosaccharide lactate which penetrates into the DBPC liposomes membranes at higher temperature, blocking thus the passage of curcumin into the lipid bilayer. However, addition of chitosan oligosaccharide lactate had no effect on the Tm. Fluorescence quenching study of curcumin establishes that the location of curcumin to be in the hydrophobic cavity of DBPC membrane.

Interaction of curcumin with diarachidonyl phosphatidyl choline (DAPC) liposomes: Chitosan protects DAPC liposomes without changing phase transition temperature but impacting membrane permeability.

The developing public interest in traditional medicine, especially plants-based drug, has prompted extensive research on the potential of naturally existing compounds. Among these compounds, curcumin is currently one of the most studied substances. In this study, we elaborate the physical properties of diarachidonyl phosphatidyl choline (DAPC) liposome using fluorescence method, where curcumin at low concentration was used as a probe molecule. In the first place, the phase transition temperature of DAPC was determined by following the fluorescence intensity of curcumin as a function of temperature, along with evaluating the effect of concentration of curcumin in the presence or absence of chitosan oligosaccharide lactate as an additional protective layer. On the other hand, quenching reactions using CPB and KI as quenchers reflected the ease of entry of different concentrations of these quenchers to the curcumin located in the hydrophobic core of the liposome which give new insight about the lipophilicity and permeability of the DAPC membrane. Finally, the partition coefficient analysis was investigated. It was concluded that curcumin has a higher partition coefficient at a temperature above the phase transition temperature of DAPC liposomes where the liposome is in the fluid liquid crystalline phase. Modulation of liposomes properties in the presence of chitosan oligosaccharide lactate layer was for the first time investigated. Chitosan oligosaccharide lactate acts as protecting layer without changing the phase transition temperature, but it affects the membrane permeability depending on solid gel and liquid crystalline phase.

Determination of Aluminum, Chromium, and Barium Concentrations in Infant Formula Marketed in Lebanon.

ABSTRACT: Infant formula is a major nutritional component for many infants and toddlers. However, the presence of contaminants, such as toxic metals, may pose increased health risks to infants. An investigation of the total concentrations of the metals aluminum (Al), barium (Ba), and chromium (Cr) in infant formulae marketed in Lebanon was performed. Powdered dairy and nondairy infant formula samples were collected from all commercially available brands (n = 39) in the Lebanese market on two production dates (78 samples in total) and analyzed for these three metals with inductively coupled plasma mass spectrometry. All brands contained detectable concentrations of Al and Ba, Cr was detected in 95% of brands. Mean (±standard deviation) concentrations of the metals were estimated as 1.54 ± 1.43 (Al), 0.256 ± 0.593 (Ba), and 0.168 ± 0.143 (Cr) (µg/g). The concentration ranges in the powdered formula were 0.080 to 7.93 (Al), 0.038 to 5.35 (Ba), and 0.041 to 0.348 (Cr) µg/g. A significant difference in the mean concentrations of Al, Ba, and Cr for the two production dates of a single brand was observed in 92, 59, and 83% of samples, respectively. The mean concentration of Al in the soy-based formula was significantly higher than that of aluminum in milk-based and corn-based formulas (P = 0.018). Cr concentrations in the continuation special formulations were significantly higher than those in the beginner formulations (P = 0.008). Our study provides the first publicly available information on metal contamination in infant formulas in Lebanon and reveals the need for frequent monitoring and surveillance of these products intended for infant consumption.