Open AccessPEG-PLA Nanocapsules Containing a Nanobiotechnological Complex of Polyhemoglobin-Tyrosinase for the Depletion of Tyrosine in Melanoma: Preparation and In Vitro Characterisation
Author(s) -
Caroline Fustier,
Thomas Ming Swi Chang
Publication year - 2012
Publication title -
journal of nanomedicine and biotherapeutic discovery
Language(s) - English
Resource type - Journals
ISSN - 2155-983X
DOI - 10.4172/2155-983x.1000103
Subject(s) - nanocapsules , dispersity , ethylene glycol , tyrosinase , copolymer , peg ratio , in vitro , chemistry , lactic acid , nuclear chemistry , materials science , polymer chemistry , nanoparticle , nanotechnology , biochemistry , organic chemistry , enzyme , polymer , finance , biology , bacteria , economics , genetics
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 and in vitro characterisation 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 detailed in vitro study and the preliminary animal study in have led to our ongoing detailed animal research to be reported in subsequent papers.