title: PEG-PLA Nanocapsules Containing a Nanobiotechnological Complex of Polyhemoglobin-Tyrosinase for the Depletion of Tyrosine in Melanoma: Preparation andIn VitroCharacterisation.
abstract: Poly (ethylene glycol)-poly (lactic acid) block-copolymer (PEG-PLA) was optimized and characterized using H-NMR spectrum and DSC thermogram. This was then used for the preparation of PEG-PLA nanocapsules containing polyhemoglobin-tyrosinase. Transmission electron microscopic and scanning electron microscopic studies showed round and non-aggregated nanocapsules with a PEG halo around each nanocapsule. Dynamic Light Scattering showed that the Z-average diameter was 65.2 ± 0.5 nm (mean ± SEM) and the polydispersity index was 0.262 ± 0.002. Factors controlling the diameters included the stirring speed of the reaction mixture and the size of the PLA block in the PEG-PLA copolymer. At the body temperature of 37oC, free tyrosinase lost all its enzyme activity after 8 hours. However, Polyhemoglobin-tyrosinase nanocapcules retained 80% of its initial activity after 8 hours. This paper contains the first part of our work on the preparation andin vitrocharacterisation of PEG-PLA Polyhemoglobin-tyrosinase nanocapsules. Preliminary result in rats shows that 1 intravenous injection lowers the systemic tyrosine level to 10-13% after 5 minutes. The result of the detailedin vitrostudy and the preliminary animal study in have led to our ongoing detailed animal research to be reported in subsequent papers.
authors.affiliation: Artificial Cells and Organs Research Center, Departments of Physiology, Medicine and Biomedical Engineering, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Caroline
authors.initials: C
authors.lastname: Fustier
authors.forename: Thomas M S
authors.initials: TM
authors.lastname: Chang
keywords: Artificial cells; Melanoma; PEG-PLA nanocapsules; Tyrosinase; Tyrosine