In Vivo and Scanning Electron Microscopy Imaging of Upconverting Nanophosphors inCaenorhabditiselegans

Abstract

We show here that upconversion phosphors can be imaged both by infrared excitation and in a scanning electron microscope. We have synthesized and characterized for this work up-converting phosphor nanoparticles nonaggregated nanocrystals of size range 50-200 nm. We have investigated the optical properties of 50-200 nm nanoparticles and found a square dependence of the emitted visible fluorescence on the infrared excitation and verified that under electron excitation similar narrow band emission spectra can be obtained as is seen with IR upconversion. The viability of the nanoparticles for biological imaging was confirmed by imaging the digestive system of the nematode worm Caenorhabditis elegans, and we have confirmed using energy-dispersive X-ray analysis that the up-conversion nanoparticles can be identified in a scanning electron microscope at high spatial resolution.

Development of gold nanoparticles coated with silica containing the antibiofilm drug cinnamaldehyde and their effects on pathogenic bacteria

“…Furthermore, when animals were fed with CNMAGNPs, they retained the ingested particles for more than 12 h. In a previous study when C. elegans was deprived of food, no or few particles were excreted. 56 The retention of particles in the intestines of treated worms indicates CNMAGNPs were biostable in the worm's digestive system, which can even degrade bacteria in ~2 min. 57 As similar report of Mohan et al, 58 after resumption of feeding the worms with E. coli OP50, the CNMA-GNPs were pushed down by the gut lumen and were excreted out of nematode within an hour.…”

Large Enhancement of Upconversion Luminescence of NaYF4:Yb3+/Er3+ Nanocrystal by 3D Plasmonic Nano‐Antennas

“…[ 1 ] Upconverison luminescence is a nonlinear process which re-emits a photon at a shorter wavelength by absorbing more than one photon successively at longer wavelengths via longlived intermediate energy states of a UCL material. [ 2 ] Unlike other nonlinear frequency upconversion effects, e.g., second harmonic generation, which requires a high pumping intensity that often has to be achieved by expensive and bulky pulsed lasers, the UCL can be excited by low power cw lasers, and even by non-coherent light sources, [ 3 ] opening the door for many important applications in various fi elds, such as life sciences, [4][5][6] medicine, [ 7 ] display, [ 8 ] laser, [ 9 , 10 ] and solar energy. [ 11 ] Driven by the potential applications, enormous endeavors have been made to develop new UCL materials, particularly, materials based on lanthanide ions such as Tm 3 + , Ho 3 + , and Er 3 + , which offer long-lived intermediate energy states, ideal for the UCL.…”

Remote activation of biomolecules in deep tissues using near-infrared-to-UV upconversion nanotransducers

“…These upconversion nanoparticles are usually made of host lattices of ceramic materials, such as LaF 3 , YF 3 , Y 2 O 3 , LaPO 4 , NaYF 4 embedded with trivalent lanthanide ions like Yb 3þ , Er 3þ , and Tm 3þ and show a unique phenomenon of absorbing NIR light and emitting UV, visible, and NIR light (10). There are a few reports exploiting NIR-to-NIR and NIRto-visible upconversion nanoparticles (UCNs) (11)(12)(13)(14); however, the use of NIR-to-UV UCNs is minimally explored (15)(16)(17).…”