title: Conjugates of folic acids with BSA-coated quantum dots for cancer cell targeting and imaging by single-photon and two-photon excitation.
abstract: Bovine serum albumin (BSA)-coated CdTe/ZnS quantum dots (BSA-QDs) were selected to conjugate with folic acid (FA), forming FA-BSA-QDs. This study aims to develop these small FA-BSA-QDs (less than 10 nm) for the diagnosis of cancers in which the FA receptor (FR) is overexpressed. The enhancement of cellular uptake in FR-positive human nasopharyngeal carcinoma cells (KB cells) for FA-BSA-QDs was found by means of confocal fluorescence microscopy under single-photon and two-photon excitation. The uptake enhancement for FA-BSA-QDs was further evaluated by flow-cytometric analysis in 10(4) KB cells, and was about 3 times higher than for BSA-QDs on average. The uptake enhancement was suppressed when KB cells had been pretreated with excess FA, reflecting that the enhancement was mediated by the association of FR at cell membranes with FA-BSA-QDs. When human embryonic kidney cells (293T) (FR-negative cells) and KB cells, respectively, were incubated with FA-BSA-QDs (1 μM) for 40 min, the FA-BSA-QD uptake by 293T cells was much weaker than that by KB cells, demonstrating that FA-BSA-QDs could undergo preferential binding on FR-positive cancer cells. These characteristics suggest that FA-BSA-QDs are potential candidates for cancer diagnosis.
authors.affiliation: State Key Laboratory of Surface Physics, Department of Physics, Fudan University, No. 220 Handan Road, Shanghai, People's Republic of China.
authors.forename: He
authors.initials: H
authors.lastname: Meng
authors.forename: Ji-Yao
authors.initials: JY
authors.lastname: Chen
authors.forename: Lan
authors.initials: L
authors.lastname: Mi
authors.forename: Pei-Nan
authors.initials: PN
authors.lastname: Wang
authors.forename: Mei-Ying
authors.initials: MY
authors.lastname: Ge
authors.forename: Yang
authors.initials: Y
authors.lastname: Yue
authors.forename: Ning
authors.initials: N
authors.lastname: Dai
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology; D019187:Cadmium Compounds / Q000737:chemistry / Q000494:pharmacology; D002277:Carcinoma; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D005492:Folic Acid / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D018613:Microscopy, Confocal; D057054:Molecular Imaging; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000175:diagnosis; D010316:Particle Size; D017785:Photons; D045663:Quantum Dots; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013440:Sulfides / Q000737:chemistry / Q000494:pharmacology; D013499:Surface Properties; D013691:Tellurium / Q000737:chemistry / Q000494:pharmacology; D017967:Zinc Compounds / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D019187:Cadmium Compounds; D013440:Sulfides; D017967:Zinc Compounds; D012710:Serum Albumin, Bovine; D005492:Folic Acid; C031238:zinc sulfide; D013691:Tellurium; C028337:cadmium telluride