Enhanced percutaneous delivery of recombinant human epidermal growth factor employing nano-liposome system.

We encapsulated recombinant human epidermal growth factor (rhEGF) into nano-liposomes (NLs) system for topical delivery. The rhEGF-loaded NLs were prepared using a high pressure homogenization method. Morphology and overall particle distribution of NLs were investigated using transmission electron microscopy (TEM) and high resolution microscope (CytoViva™). Particle size, zeta (ζ) potential and encapsulation efficiency were measured and the percutaneous delivery of NLs was evaluated using Franz diffusion cells and immunofluorescence confocal laser scanning microscopy (CLSM). The mean particle size, zeta potential and encapsulation efficiency of the NLs were 155.57 ± 2.59 nm, -57.92 ± 4.35 mV and 9.00 ± 0.39%, respectively. TEM and microscopic analysis showed spherical, very even-sized vesicles approximately 150 nm. The skin permeation and localization of rhEGF were enhanced by NLs. CLSM image analysis provided that the NLs enhanced the permeation and localization of rhEGF in rat skin by facilitating entry through pores of skin.

Development of a membrane strip immunosensor utilizing ruthenium as an electro-chemiluminescent signal generator.

A photometric immunosensor that can be used for on-site diagnosis has been constructed. The sensor system was assembled by partially superimposing a nitrocellulose membrane strip (the lower) containing an immobilized antigen on the surface with a glass fiber membrane strip (the upper) including two electrodes on the opposite surfaces. To amplify the signal, we introduced a liposome, containing ruthenium molecules trapped in the core, chemically coupled to an antibody specific to the analyte (e.g. Legionella antigen). In the presence of the analyte, immune complexes were formed by antigen-antibody reactions upon addition of the immuno-liposome into a sample. This mixture was then absorbed by the capillary action from the bottom of the membrane strip. The liposome particles in the complexes were carried by a medium through the antigen pad without interaction, while free immuno-liposome was trapped by immune reactions on the pad surfaces. The aqueous medium influx into the glass pad dissolved a detergent pre-located within the compartment and the liposome rupture thereby released ruthenium molecules into the solution. The molecules were oxidized on the electrode surfaces and produced an electro-chemiluminescence (ECL) in proportion to the analyte concentration. The signal generation based on ECL resulted in an exponential dose-response pattern and the analyte detection limit of 2 ng/ml was approximately 10-fold more sensitive than that obtained from a conventional system.