Cell tracking and detection of molecular expression in live cells using lipid-enclosed CdSe quantum dots as contrast agents for epi-third harmonic generation microscopy.
We demonstrated that lipid-enclosed CdSe quantum dots (LEQDs) can function as versatile contrast agents in epi-detection third harmonic generation (THG) microscopy for biological applications in vivo. With epi-THG intensities 20 times stronger than corresponding fluorescence intensities from the same LEQDs under the same conditions of energy absorption, such high brightness LEQDs were proved for the abilities of cell tracking and detection of specific molecular expression in live cancer cells. Using nude mice as an animal model, the distribution of LEQD-loaded tumor cells deep in subcutaneous tissues were imaged with high THG contrast. This is the first demonstration that THG contrast can be manipulated in vivo with nanoparticles. By linking LEQDs with anti-Her2 antibodies, the expression of Her2/neu receptors in live breast cancer cells could also be easily detected through THG. Compared with fluorescence modalities, the THG modality also provides the advantage of no photobleaching and photoblinkin g effects. Combined with a high penetration 1230 nm laser, these novel features make LEQDs excellent THG contrast agents for in vivo deep-tissue imaging in the future.
Department of Electrical Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan.
Chieh-Feng
CF
Chang
Chao-Yu
CY
Chen
Fu-Hsiung
FH
Chang
Shih-Peng
SP
Tai
Cheng-Ying
CY
Chen
Che-Hang
CH
Yu
Yi-Bing
YB
Tseng
Tsung-Han
TH
Tsai
I-Shuo
IS
Liu
Wei-Fang
WF
Su
Chi-Kuang
CK
Sun
D000818:Animals; D019187:Cadmium Compounds / Q000737:chemistry; D045744:Cell Line, Tumor; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D003287:Contrast Media; D004337:Drug Carriers / Q000737:chemistry; D020869:Gene Expression Profiling / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008055:Lipids / Q000737:chemistry*; D051379:Mice; D008819:Mice, Nude; D008856:Microscopy, Fluorescence / Q000379:methods*; D015336:Molecular Probe Techniques; D009369:Neoplasms / Q000473:pathology*; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry
D019187:Cadmium Compounds; D020099:Coated Materials, Biocompatible; D003287:Contrast Media; D004337:Drug Carriers; D008055:Lipids; D018036:Selenium Compounds; C058667:cadmium selenide