The correlation of haptenation of gold nanoparticles and cysteine modified screen printed carbon electrode by impedance technique with local lymph node assay data.

Skin sensitization occurs when a skin sensitizer binds covalently to skin proteins through the haptenation process. The objective of this study was to correlate the electrochemical impedance spectroscopy (EIS) data of a screen printed carbon electrode (SPCE) modified with cysteine and gold nanoparticles (AuNPs) with local lymph node assay (LLNA) data as a potential skin sensitizer biosensor. The EIS was used to quantify variations in charge transfer resistance of skin sensitizers (ΔRCTskin sensitizer) due to different binding rates of skin sensitizers to cysteine. SPCE was modified through electrodeposition of AuNPs/thiourea/self-assembly of AuNPs/cysteine (assigned as ETSC) for the detection of skin sensitizers. Surface analysis of modified SPCEs using FESEM and EDX revealed a smooth surface with an uneven distribution of cysteine with AuNPs molecules. The ETSC modified SPCE showed a significant skin sensitizer biosensor since the ΔRCTskin sensitizer readings were increased proportionally to the strength of the skin sensitizers, with strong/extreme skin sensitizers displaying higher ΔRCTskin sensitizer readings compared to moderate and weak/non-skin sensitizers. The skin sensitization analysis from this work was compared to LLNA (animal study), human cell line activation (h-CLAT), direct peptide reactivity assay (DPRA), and KeratinoSens™, surface plasmon resonance (SPR) matched the categorization of LLNA in the following descending order: 96%, 92%, 82%, 70%, 70%, and 12%. With just an 8% mismatch with LLNA data, the EIS approach used in this study could be used as a screening tool for skin sensitizers.

Empty nano and micro-structured lipid carriers of virgin coconut oil for skin moisturisation.

Virgin coconut oil (VCO) is the finest grade of coconut oil, rich in phenolic content, antioxidant activity and contains medium chain triglycerides (MCTs). In this work formulation, characterisation and penetration of VCO-solid lipid particles (VCO-SLP) have been studied. VCO-SLP were prepared using ultrasonication of molten stearic acid and VCO in an aqueous solution. The electron microscopy imaging revealed that VCO-SLP were solid and spherical in shape. Ultrasonication was performed at several power intensities which resulted in particle sizes of VCO-SLP ranged from 0.608 ± 0.002 µm to 44.265 ± 1.870 µm. The particle size was directly proportional to the applied power intensity of ultrasonication. The zeta potential values of the particles were from -43.2 ± 0.28 mV to -47.5 ± 0.42 mV showing good stability. The cumulative permeation for the smallest sized VCO-SLP (0.608 µm) was 3.83 ± 0.01 µg/cm(2) whereas for larger carriers it was reduced (3.59 ± 0.02 µg/cm(2)). It is concluded that SLP have the potential to be exploited as a micro/nano scale cosmeceutical carrying vehicle for improved dermal delivery of VCO.