Upconversion and downconversion nanoparticles for biophotonics and nanomedicine

Interaction of LiYF4:Yb3+/Er3+/Ho3+/Tm3+@LiYF4:Yb3+ upconversion nanoparticles, molecularly imprinted polymers, and templates

“…[7][8][9] Among the luminescent NPs, rare earth element-doped upconversion NPs (UCNPs) are of great interest because of their high luminescence, lack of toxicity toward biological organisms, narrow absorption and emission peaks, long lifetime, and virtually zero interference background. 10,11 In addition, UCNPs can emit highenergy photons in the UV or visible regions of the electromagnetic spectrum under the excitation of low-energy near-infrared (NIR) photons. The use of NIR photons can also reduce auto-uorescence so as to minimize the background light interference and improve the detection sensitivity.…”

Advances in Biomimetic Nanoparticles for Targeted Cancer Therapy and Diagnosis

“…Upconversion nanoparticles are a type of inorganic nanoparticle which typically contains lanthanide-based transition metals such as Yb 3+ , Tm 3+ , Er 3+ or Ho 3+ . These nanoparticles, upon excitation by near-infrared light (low-energy photons), are able to produce an emission with a shorter wavelength (blue or green, high-energy photons) [ 111 ]. The authors of this study used PEGylated β-NaYF 4 :Er 3+ ,Yb 3+ upconversion nanoparticles coated with cancer cell membranes derived from MDA-MB-435 human breast cancer cells (MDA nanoparticles), DU 145 human prostate cancer cells (DU nanoparticles), CAL 27 human squamous cancer cells (CAL nanoparticles) and HCT 116 human colorectal cancer cells (HCT nanoparticles).…”

Nanomaterial application in bio/sensors for the detection of infectious diseases

“…Upconversion nanoparticles (UCNPs) with near-infrared (NIR) excitation characteristics have received considerable attention in bio-imaging (e.g. nanoprobe) [ 67 ]. The most used of UCNP-based nanoparticles are in fluorescence resonance energy transfer, FRET sensor.…”

“…Fluorides due to their high chemical stability, low photon energy, are well-suited hosts for UCNPs. Synthetic procedures like co-precipitation, thermal decomposition, hydro/solvothermal synthesis, and sonochemical methods have been reported in the manufacturing of UCNPs[ 67 ]. These nanoparticles are characterized by low toxicity, sharp emission band, long fluorescence lifetime, less light scattering, high photostability, tunable multicolor emission, high light penetration depth, and larger anti-stocks shifts, when compared with more conventional fluorochromes, making them particularly useful for biosensor applications[ 68 , 69 ].…”