Upconversion nanoparticle based LRET system for sensitive detection of MRSA DNA sequence.

In this short communication we report an efficient and versatile method for the detection of methicillin-resistant staphylococcus aureus (MRSA) DNA sequence with high sensitivity and specificity. This method is based on upconversion nanoparticles (UCNs) and luminescence resonance energy transfer (LRET) between NaYF4:Yb, Er UCNs, the energy donor, and carboxytetramethylrhodamine (TAMRA), the energy acceptor. The NaYF4:Yb, Er UCNs were prepared with citrate capping thus dispersible in aqueous solutions. MRSA capture oligonucleotides were covalently immobilized onto the surface of the UCNs. TAMRA labeled MRSA DNA report oligonucleotides were brought close to the UCNs upon sandwich hybridization between the capture and report oligonucleotides and a long MRSA target DNA, resulting in an efficient LRET. Specific detection of MRSA DNA sequences with a detection limit as low as 0.18nM was achieved using this method. To the best of our knowledge, this is the first report to detect MRSA DNA sequence by using UCNs as energy donor through an efficient LRET process.