We develop luminescence platforms that can be used as point of care systems for determinig the presence and concentration of specific oligonucleotide sequences. We carried out sensors with detection limits of 50 fM based on:

1) ssDNA functionalized magnetic microparticles that capture and concentrate ssDNA-UCNPs on a solid support.

2) photoligation reaction that covalently links the ssDNA-UCNPs and the ssDNA magnetic microparticles, allowing stringent washes.

Ag2S nanoparticles are the staple for high-resolution preclinical imaging and sensing owing to their photochemical stability, low toxicity, and photoluminescence in the second biological window.

We develop methodologies to improve their photoluminescence quantum yield. We carried out a sonochemical etching process that reduces the density of quenching surface states.

Metallic nanostructures have the potential to modify the anti-Stokes emission of UCNPs by coupling their plasmon resonance with either the excitation or the emission wavelength of the UCNPs.

We find a transition from strong upconversion luminescence quenching to enhancement by increasing the size of the gold nanoparticles (AuNPs), coupled to the UCNPs.

FRET with UCNPs as donors and QDs as aceptors has been regarded as a promising tool for biosensing applications.

We analyze the FRET efficiency with the UCNP-QD distance which is controlled by a nanometric silica shell around the UCNP.