Pakavadee Rakthong.. A study towards the development of a rapid diagnostic test to detect microbial specific nucleotide sequences. Doctoral Degree(Microbiology). Mahidol University. Mahidol University Library and Knowledge Center. : Mahidol University, 2008.
A study towards the development of a rapid diagnostic test to detect microbial specific nucleotide sequences
Abstract:
The aim of the present study was to prepare luminol encapsulated biotinylated liposomes to be used as generic signal generators capable of conjugation to biotinylated biomolecules. Liposome has been prepared using two types of biotinylated phospholipids: biotin.PEG2000disteroylphosphatidyl ethanolamine (B-PEG-DSPE) and biotin caproyl dipalmitoylphosphatidyl ethanolamine (B-Cap-DPPE) with luminol entrapped. These liposomes were characterized in terms of size, lamellarity, stability, and encapsulation efficiency. The length and chemical nature of spacers in the two biotinylated phospholipids and also the biotin ligand density were shown to affect the interaction of the liposome with soluble or immobilized streptavidin. The lysis of the liposome and the effects on the chemiluminescent reactions of liberated luminol by various detergents (SDS, Triton X-100 and deoxycholate (DOC)) were studied and DOC was shown to be the most suitable reagent. Using biotinylated 20-mer oligonucleotides (ONTs) as prototypes, the specific hybridization of the (+) and (-) strands of ONT immobilized on a microtiter plate were studied using streptavidin coated, luminol encapsulated biotinylated liposomes. It was found that the streptavidin coated liposome could specifically bind to the hybridized biotinylated ONTs and served as a signal generator. The hybridization was inhibited only by the corresponding ONT with the detection limit of 20 picomole. This streptavidin coated/luminal-encapsulated biotinylated liposome could serve as a versatile, generic signal generator capable of conjugation to, and for the detection of, biotinylated biomolecules.