EXPERIMENTS: New graphene-philic surfactants carrying aromatic moieties in the hydrophilic headgroups and hydrophobic tails were synthesized by swapping the traditional sodium counterion with anilinium. 1H NMR spectroscopy was used to characterize the surfactants. These custom-made surfactants were used to assist the dispersion of GNPs in natural rubber latex matrices for the preparation of conductive nanocomposites. The properties of nanocomposites with the new anilinium surfactants were compared with commercial sodium surfactant sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), and the previously synthesized aromatic tri-chain sodium surfactant TC3Ph3 (sodium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3phenylpropoxy)carbonyl) pentane-2-sulfonate). Structural properties of the nanocomposites were studied using Raman spectroscopy, field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM). Electrical conductivity measurements and Zeta potential measurements were used to assess the relationships between total number of aromatic groups in the surfactant molecular structure and nanocomposite properties. The self-assembly structure of surfactants in aqueous systems and GNP dispersions was assessed using small-angle neutron scattering (SANS).
FINDINGS: Among these different surfactants, the anilinium version of TC3Ph3 namely TC3Ph3-AN (anilinium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3phenylpropoxy)carbonyl) pentane-2-sulfonate) was shown to be highly efficient for dispersing GNPs in the NRL matrices, increasing electrical conductivity eleven orders of magnitude higher than the neat rubber latex. Comparisons between the sodium and anilinium surfactants show significant differences in the final properties of the nanocomposites. In general, the strategy of increasing the number of surfactant-borne aromatic groups by incorporating anilinium ions in surfactant headgroups appears to be effective.
Materials and Methods: Biodegradable polymeric microneedle arrays were fabricated out of poly lactic-co-glycolic acid (PLGA) using the micromolding technique under aseptic conditions, and the morphology of the microneedles was characterized using light microscopy. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was used to rule out drug-polymer interactions. Standard procedures were used to analyze the prepared microneedle arrays for in vitro drug release and to perform a microneedle insertion test. Enzyme-linked immunosorbent assay was used to quantify rHuKGF.
Results: The PLGA polymer was safe for use in the fabrication of rHuKGF microneedles as there was no interaction between the drug and the polymer. The fabricated rHuKGF microneedle arrays had fully formed microneedles with a height of 600 µm and a base of 300 µm. The drug from the microneedle patch was released in vitro within 30 minutes. The strength of the microneedles in the patch was good, as they were able to reach a depth of 381±3.56 µm into parafilm without any structural change or fracture.
Conclusion: Microneedle transdermal patches were successfully prepared for rHuKGF, and their evaluation suggested excellent quality and uniformity of patch characteristics. This can have potential applications in the therapeutic arena, offering advantages in terms of reduced dosing frequency, improved patient compliance, and bioavailability.
METHODS: A protein of 58 kd with an isoelectric point of 8.45 was purified from raw latex and from latex gloves and identified as the major allergen, completely blocking specific IgE antibodies in the serum of latex-sensitized subjects. The allergen is a noncovalent homotetramer molecule, in which the 14.6 kd monomer was identified, by amino acid composition and sequence homologies of tryptic peptides, to be the rubber elongation factor found in natural latex of the Malaysian rubber tree.
RESULTS: Competitive immunoinhibition tests showed that the starch powder covering the finished gloves is the airborne carrier of the allergen, resulting in bronchial asthma on inhalation. The purified allergen can induce allergic reactions in the nanogram range.
CONCLUSION: The identification of the allergen (Hev b I) may help to eliminate it during the production of latex-based articles in the future.