title: Folate-receptor-mediated delivery of InP quantum dots for bioimaging using confocal and two-photon microscopy.
abstract: A novel method for the synthesis of highly monodispersed hydrophillic InP-ZnS nanocrystals and their use as luminescence probes for live cell imaging is reported. Hydrophobic InP-ZnS nanocrystals are prepared by a new method that yields high-quality, luminescent core-shell nanocrystals within 6-8 h of total reaction time. Then by carefully manipulating the surface of these passivated nanocrystals, aqueous dispersions of folate-conjugated nanocrystals (folate-QDs) with high photostability are prepared. By use of confocal microscopy, we demonstrate the receptor-mediated delivery of folic acid conjugated quantum dots into folate-receptor-positive cell lines such as KB cells. These folate-QDs tend to accumulate in multi-vescicular bodies of KB cells after 6 h of incubation. Receptor-mediated delivery was confirmed by comparison with the uptake of these particles in folate-receptor-negative cell lines such as A549. Efficient two-photon excitation of these particles and two-photon imaging using these particles are also demonstrated. The use of these InP-ZnS nanoparticles and their efficient two-photon excitation can be potentially useful for deep tissue imaging for future in vivo studies.
authors.affiliation: Institute for Laser, Photonics and Biophotonics, and Department of Chemistry, The University of Buffalo, Buffalo, New York 14260-3000, USA.
authors.forename: Dhruba J
authors.initials: DJ
authors.lastname: Bharali
authors.forename: Derrick W
authors.initials: DW
authors.lastname: Lucey
authors.forename: Harishankar
authors.initials: H
authors.lastname: Jayakumar
authors.forename: Haridas E
authors.initials: HE
authors.lastname: Pudavar
authors.forename: Paras N
authors.initials: PN
authors.lastname: Prasad
mesh_terms: D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism*; D058973:Folate Receptors, GPI-Anchored; D006801:Humans; D049408:Luminescent Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism*; D008853:Microscopy / Q000379:methods; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D017785:Photons; D045663:Quantum Dots; D011956:Receptors, Cell Surface / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D005456:Fluorescent Dyes; D058973:Folate Receptors, GPI-Anchored; D049408:Luminescent Agents; D011956:Receptors, Cell Surface