Quantum dots (QDs) are a group of semiconducting nanomaterials with unique optical and electronic properties. They have distinct advantages over traditional fluorescent organic dyes in chemical and biological studies in terms of tunable emission spectra, signal brightness, photostability, and so forth. Currently, the major type of QDs is the heavy metal-containing II-IV, IV-VI, or III-V QDs. Silicon QDs and conjugated polymer dots have also been developed in order to lower the potential toxicity of the fluorescent probes for biological applications. Aqueous solubility is the common problem for all types of QDs when they are employed in the biological researches, such as in vitro and in vivo imaging. To circumvent this problem, ligand exchange and polymer coating are proven to be effective, besides synthesizing QDs in aqueous solutions directly. However, toxicity is another big concern especially for in vivo studies. Ligand protection and core/shell structure can partly solve this problem. With the rapid development of QDs research, new elements and new morphologies have been introduced to this area to fabricate more safe and efficient QDs for biological applications. 1. Introduction Semiconductor nanocrystals, or so-called quantum dots (QDs), show unique optical and electronic properties, including size-tunable light emission, simultaneous excitation of multiple fluorescence colors, high signal brightness, long-term photostability, and multiplex capabilities [1–4]. Such QDs have significant advantages in chemical and biological researches in contrast to traditional fluorescent organic dyes and green fluorescent proteins on account of their photobleaching, low signal intensity, and spectral overlapping [5–7]. These properties of QDs have attracted great interest in biology and medicine in recent years. At present QDs are considered to be potential candidates as luminescent probes and labels in biological applications, ranging from molecular histopathology, disease diagnosis, to biological imaging [8–10]. Numerous studies have reported the use of QDs for in vitro or in vivo imaging of sentinel lymph nodes [11–17], tumor-specific receptors [18–20], malignant tumor detectors [21], and tumor immune responses [22]. However, the major concerns about potential toxicity of II-IV QDs (such as CdTe and CdSe) have cast doubts on their practical use in biology and medicine. Indeed, several studies have reported that size, charge, coating ligands, and oxidative, photolytic, and mechanical stability, each can contribute to the cytotoxicity of cadmium-containing QDs.
References
[1]
P. Alivisatos, “The use of nanocrystals in biological detection,” Nature Biotechnology, vol. 22, no. 1, pp. 47–52, 2004.
[2]
X. H. Gao, L. L. Yang, J. A. Petros, F. F. Marshall, J. W. Simons, and S. M. Nie, “In vivo molecular and cellular imaging with quantum dots,” Current Opinion in Biotechnology, vol. 16, no. 1, pp. 63–72, 2005.
[3]
X. Michalet, F. F. Pinaud, L. A. Bentolila et al., “Quantum dots for live cells, in vivo imaging, and diagnostics,” Science, vol. 307, no. 5709, pp. 538–544, 2005.
[4]
A. M. Smith, H. W. Duan, A. M. Mohs, and S. M. Nie, “Bioconjugated quantum dots for in vivo molecular and cellular imaging,” Advanced Drug Delivery Reviews, vol. 60, no. 11, pp. 1226–1240, 2008.
[5]
W. C. W. Chan and S. M. Nie, “Quantum dot bioconjugates for ultrasensitive nonisotopic detection,” Science, vol. 281, no. 5385, pp. 2016–2018, 1998.
[6]
B. Dubertret, P. Skourides, D. J. Norris, V. Noireaux, A. H. Brivanlou, and A. Libchaber, “In vivo imaging of quantum dots encapsulated in phospholipid micelles,” Science, vol. 298, no. 5599, pp. 1759–1762, 2002.
[7]
A. Konkar, S. Y. Lu, A. Madhukar, S. M. Hughes, and A. P. Alivisatos, “Semiconductor nanocrystal quantum dots on single crystal semiconductor substrates: high resolution transmission electron microscopy,” Nano Letters, vol. 5, no. 5, pp. 969–973, 2005.
[8]
Y. Xing, Q. Chaudry, C. Shen et al., “Bioconjugated quantum dots for multiplexed and quantitative immunohistochemistry,” Nature Protocols, vol. 2, no. 5, pp. 1152–1165, 2007.
[9]
M. V. Yezhelyev, A. Al-Hajj, C. Morris et al., “In situ molecular profiling of breast cancer biomarkers with multicolor quantum dots,” Advanced Materials, vol. 19, no. 20, pp. 3146–3151, 2007.
[10]
A. M. Smith, S. Dave, S. M. Nie, L. True, and X. Gao, “Multicolor quantum dots for molecular diagnostics of cancer,” Expert Review of Molecular Diagnostics, vol. 6, no. 2, pp. 231–244, 2006.
[11]
A. Robe, E. Pic, H. P. Lassalle, L. Bezdetnaya, F. Guillemin, and F. Marchal, “Quantum dots in axillary lymph node mapping: biodistribution study in healthy mice,” BMC Cancer, vol. 8, no. 1, pp. 111–119, 2008.
[12]
M. Takeda, H. Tada, H. Higuchi et al., “In vivo single molecular imaging and sentinel node navigation by nanotechnology for molecular targeting drug-delivery systems and tailor-made medicine,” Breast Cancer, vol. 15, no. 2, pp. 145–152, 2008.
[13]
S. Kim, Y. T. Lim, E. G. Soltesz et al., “Near-infrared fluorescent type II quantum dots for sentinel lymph node mapping,” Nature Biotechnology, vol. 22, no. 1, pp. 93–97, 2004.
[14]
E. G. Soltesz, S. Kim, R. G. Laurence et al., “Intraoperative sentinel lymph node mapping of the lung using near-infrared fluorescent quantum dots,” Annals of Thoracic Surgery, vol. 79, no. 1, pp. 269–277, 2005.
[15]
E. G. Soltesz, S. Kim, S. W. Kim et al., “Sentinel lymph node mapping of the gastrointestinal tract by using invisible light,” Annals of Surgical Oncology, vol. 13, no. 3, pp. 386–396, 2006.
[16]
C. P. Parungo, S. Ohnishi, S. W. Kim et al., “Intraoperative identification of esophageal sentinel lymph nodes with near-infrared fluorescence imaging,” Journal of Thoracic and Cardiovascular Surgery, vol. 129, no. 4, pp. 844–850, 2005.
[17]
B. Ballou, L. A. Ernst, S. Andreko et al., “Sentinel lymph node imaging using quantum dots in mouse tumor models,” Bioconjugate Chemistry, vol. 18, no. 2, pp. 389–396, 2007.
[18]
P. Diagaradjane, J. M. Orenstein-Cardona, N. E. Colon-Casasnovas et al., “Imaging epidermal growth factor receptor expression in vivo: pharmacokinetic and biodistribution characterization of a bioconjugated quantum dot nanoprobe,” Clinical Cancer Research, vol. 14, no. 3, pp. 731–741, 2008.
[19]
X. H. Gao, Y. Y. Cui, R. M. Levenson, L. W. K. Chung, and S. M. Nie, “In vivo cancer targeting and imaging with semiconductor quantum dots,” Nature Biotechnology, vol. 22, no. 8, pp. 969–976, 2004.
[20]
D. S. Lidke, P. Nagy, R. Heintzmann et al., “Quantum dot ligands provide new insights into erbB/HER receptor-mediated signal transduction,” Nature Biotechnology, vol. 22, no. 2, pp. 198–203, 2004.
[21]
L. F. Qi and X. H. Gao, “Quantum dot—amphipol nanocomplex for intracellular delivery and real-time imaging of siRNA,” ACS Nano, vol. 2, no. 7, pp. 1403–1410, 2008.
[22]
D. Sen, T. J. Deerinck, M. H. Ellisman, I. Parker, and M. D. Cahalan, “Quantum dots for tracking dendritic cells and priming an immune response in vitro and in vivo,” PLoS One, vol. 3, no. 9, Article ID e3290, 2008.
[23]
A. M. Derfus, W. C. W. Chan, and S. N. Bhatia, “Probing the cytotoxicity of semiconductor quantum dots,” Nano Letters, vol. 4, no. 1, pp. 11–18, 2004.
[24]
R. Hardman, “Toxicological review of quantum dots: toxicity depends on physicochemical and environmental factors,” Environmental Health Perspectives, vol. 114, no. 2, pp. 165–172, 2006.
[25]
G. N. Guo, W. Liu, J. G. Liang, H. B. Xu, Z. K. He, and X. L. Yang, “Preparation and characterization of novel CdSe quantum dots modified with poly (D, L-lactide) nanoparticles,” Materials Letters, vol. 60, no. 21-22, pp. 2565–2568, 2006.
[26]
Y. Pan, S. Neuss, A. Leifert et al., “Size-dependent cytotoxicity of gold nanoparticles,” Small, vol. 3, no. 11, pp. 1941–1949, 2007.
[27]
M. L. Schipper, Z. Cheng, S. W. Lee et al., “MicroPET-based biodistribution of quantum dots in living mice,” Journal of Nuclear Medicine, vol. 48, no. 9, pp. 1511–1518, 2007.
[28]
P. Diagaradjane, A. Deorukhkar, J. G. Gelovani, D. M. Maru, and S. Krishnan, “Gadolinium chloride augments tumor-specific imaging of targeted quantum dots in vivo,” ACS Nano, vol. 4, no. 7, pp. 4131–4141, 2010.
[29]
M. Q. Chu, X. Song, D. Cheng, S. P. Liu, and J. Zhu, “Preparation of quantum dot-coated magnetic polystyrene nanospheres for cancer cell labelling and separation,” Nanotechnology, vol. 17, no. 13, pp. 3268–3273, 2006.
[30]
F. Corsi, C. de Palma, M. Colombo et al., “Towards ideal magnetofluorescent nanoparticles for bimodal detection of breast-cancer cells,” Small, vol. 5, no. 22, pp. 2555–2564, 2009.
[31]
A. Quarta, R. D. Corato, L. Manna, A. Ragusa, and T. Pellegrino, “Fluorescent-magnetic hybrid nanostructures: preparation, properties, and applications in biology,” IEEE Transactions on Nanobioscience, vol. 6, no. 4, pp. 298–308, 2007.
[32]
P. N. Prasad, Biophotonics, Wiley-Interscience, Hoboken, NJ, USA, 2003.
[33]
H. Wittcoff, B. G. Reuben, and J. S. Plotkin, Industrial organic chemicals, Wiley-Interscience, Hoboken, NJ, USA, 2004.
[34]
B. O. Dabbousi, J. Rodriguez-Viejo, F. V. Mikulec et al., “(CdSe)ZnS core-shell quantum dots: synthesis and characterization of a size series of highly luminescent nanocrystallites,” Journal of Physical Chemistry B, vol. 101, no. 46, pp. 9463–9475, 1997.
[35]
S. T. Selvan, “Silica-coated quantum dots and magnetic nanoparticles for bioimaging applications,” Biointerphases, vol. 5, no. 3, pp. FA110–FA115, 2010.
[36]
J. H. Park, L. Gu, G. Von Maltzahn, E. Ruoslahti, S. N. Bhatia, and M. J. Sailor, “Biodegradable luminescent porous silicon nanoparticles for in vivo applications,” Nature Materials, vol. 8, no. 4, pp. 331–336, 2009.
[37]
X. H. Gao and S. M. Nie, “Doping mesoporous materials with multicolor quantum dots,” Journal of Physical Chemistry B, vol. 107, no. 42, pp. 11575–11578, 2003.
[38]
F. Erogbogbo, K. T. Yong, I. Roy et al., “In vivo targeted cancer imaging, sentinel lymph node mapping and multi-channel imaging with biocompatible silicon nanocrystals,” Nano Letters, vol. 5, no. 1, pp. 413–423, 2011.
[39]
W. J. Parak, D. Gerion, D. Zanchet et al., “Conjugation of DNA to silanized colloidal semiconductor nanocrystalline quantum dots,” Chemistry of Materials, vol. 14, no. 5, pp. 2113–2119, 2002.
[40]
S. Sato and M. T. Swihart, “Propionic-acid-terminated silicon nanoparticles: synthesis and optical characterization,” Chemistry of Materials, vol. 18, no. 17, pp. 4083–4088, 2006.
[41]
R. D. Tilley and K. Yamamoto, “The microemulsion synthesis of hydrophobic and hydrophilic silicon nanocrystals,” Advanced Materials, vol. 18, no. 15, pp. 2053–2056, 2006.
[42]
J. H. Warner, A. Hoshino, K. Yamamoto, and R. D. Tilley, “Water-soluble photoluminescent silicon quantum dots,” Angewandte Chemie International Edition, vol. 44, no. 29, pp. 4550–4554, 2005.
[43]
L. H. Chen, D. W. McBranch, H. L. Wang, R. Helgeson, F. Wudl, and D. G. Whitten, “Highly sensitive biological and chemical sensors based on reversible fluorescence quenching in a conjugated polymer,” Proceedings of the National Academy of Sciences, vol. 96, no. 22, pp. 12287–12292, 1999.
[44]
C. H. Fan, S. Wang, J. W. Hong, G. C. Bazan, K. W. Plaxco, and A. J. Heeger, “Beyond superquenching: hyper-efficient energy transfer from conjugated polymers to gold nanoparticles,” Proceedings of the National Academy of Sciences, vol. 100, no. 11, pp. 6297–6301, 2003.
[45]
J. H. Burroughes, D. D. C. Bradley, A. R. Brown et al., “Light-emitting diodes based on conjugated polymers,” Nature, vol. 347, no. 6293, pp. 539–541, 1990.
[46]
R. H. Friend, R. W. Gymer, A. B. Holmes et al., “Electroluminescence in conjugated polymers,” Nature, vol. 397, no. 6715, pp. 121–128, 1999.
[47]
F. So, B. Krummacher, M. K. Mathai, D. Poplavskyy, S. A. Choulis, and V. E. Choong, “Recent progress in solution processable organic light emitting devices,” Journal of Applied Physics, vol. 102, no. 9, Article ID 091101, 2007.
[48]
C. F. Wu, C. Szymanski, and J. McNeill, “Preparation and encapsulation of highly fluorescent conjugated polymer nanoparticles,” Langmuir, vol. 22, no. 7, pp. 2956–2960, 2006.
[49]
C. F. Wu, C. Szymanski, Z. Cain, and J. McNeill, “Conjugated polymer dots for multiphoton fluorescence imaging,” Journal of the American Chemical Society, vol. 129, no. 43, pp. 12904–12905, 2007.
[50]
C. F. Wu, B. Bull, C. Szymanski, K. Christensen, and J. McNeill, “Multicolor conjugated polymer dots for biological fluorescence imaging,” ACS Nano, vol. 2, no. 11, pp. 2415–2423, 2008.
[51]
C. B. Murray, D. J. Norris, and M. G. Bawendi, “Synthesis and characterization of nearly monodisperse CdE ( , Se, Te) semiconductor nanocrystallites,” Journal of the American Chemical Society, vol. 115, no. 19, pp. 8706–8715, 1993.
[52]
T. Rajh, O. I. Micic, and A. J. Nozik, “Synthesis and characterization of surface-modified colloidal CdTe quantum dots,” Journal of Physical Chemistry, vol. 97, no. 46, pp. 11999–12003, 1993.
[53]
C. Ding, Y. Li, and Y. Qu, “Synthesizing quantum dot with uniform grain diameter distribution in water phase comprises preparing molding board agent and cadmium sulfydryl composite precursor, producing water solution of sodium borohydride, and synthesizing quantum dot,” East China Normal University, 2010.
[54]
M. A. Correa-Duarte, M. Giersig, N. A. Kotov, and L. M. Liz-Marzan, “Control of packing order of self-assembled monolayers of magnetite nanoparticles with and without SiO2 coating by microwave irradiation,” Langmuir, vol. 14, no. 22, pp. 6430–6435, 1998.
[55]
H. F. Qian, X. Qiu, L. Li, and J. C. Ren, “Microwave-assisted aqueous synthesis: a rapid approach to prepare highly luminescent ZnSe(S) alloyed quantum dots,” Journal of Physical Chemistry B, vol. 110, no. 18, pp. 9034–9040, 2006.
[56]
F. Pinaud, D. King, H. P. Moore, and S. Weiss, “Bioactivation and cell targeting of semiconductor CdSe/ZnS nanocrystals with phytochelatin-related peptides,” Journal of the American Chemical Society, vol. 126, no. 19, pp. 6115–6123, 2004.
[57]
T. Pellegrino, L. Manna, S. Kudera et al., “Hydrophobic nanocrystals coated with an amphiphilic polymer shell: a general route to water soluble nanocrystals,” Nano Letters, vol. 4, no. 4, pp. 703–707, 2004.
[58]
C. A. J. Lin, R. A. Sperling, J. K. Li et al., “Design of an amphiphilic polymer for nanoparticle coating and functionalization,” Small, vol. 4, no. 3, pp. 334–341, 2008.
[59]
J. H. Phan, R. A. Moffitt, T. H. Stokes et al., “Convergence of biomarkers, bioinformatics and nanotechnology for individualized cancer treatment,” Trends in Biotechnology, vol. 27, no. 6, pp. 350–358, 2009.
[60]
J. Liu, S. K. Lau, V. A. Varma, B. A. Kairdolf, and S. M. Nie, “Multiplexed detection and characterization of rare tumor cells in Hodgkin's lymphoma with multicolor quantum dots,” Analytical Chemistry, vol. 82, no. 14, pp. 6237–6243, 2010.
[61]
H. S. Cho, Z. Y. Dong, G. M. Pauletti et al., “Fluorescent, superparamagnetic nanospheres for drug storage, targeting, and imaging: a multifunctional nanocarrier system for cancer diagnosis and treatment,” ACS Nano, vol. 4, no. 9, pp. 5398–5404, 2010.
[62]
Y. A. Cao, K. Yang, Z. G. Li, C. Zhao, C. M. Shi, and J. Yang, “Near-infrared quantum-dot-based non-invasive in vivo imaging of squamous cell carcinoma U14,” Nanotechnology, vol. 21, no. 47, Article ID 475104, 2010.
[63]
W. Jiang, A. Singhal, J. N. Zheng, C. Wang, and W. C. W. Chan, “Optimizing the synthesis of red- to near-IR-emitting CdS-capped CdTexSe1-x alloyed quantum dots for biomedical imaging,” Chemistry of Materials, vol. 18, no. 20, pp. 4845–4854, 2006.
[64]
W. J. M. Mulder, R. Koole, R. J. Brandwijk et al., “Quantum dots with a paramagnetic coating as a bimodal molecular imaging probe,” Nano Letters, vol. 6, no. 1, pp. 1–6, 2006.
[65]
W. J. M. Mulder, G. J. Strijkers, G. A. F. V. Tilborg, D. P. Cormode, Z. A. Fayad, and K. Nicolay, “Nanoparticulate assemblies of amphiphiles and diagnostically active materials for multimodality imaging,” Accounts of Chemical Research, vol. 42, no. 7, pp. 904–914, 2009.
[66]
J. H. Bang, W. H. Suh, and K. S. Suslick, “Quantum dots from chemical aerosol flow synthesis: preparation, characterization, and cellular imaging,” Chemistry of Materials, vol. 20, no. 12, pp. 4033–4038, 2008.
[67]
B. R. Hyun, H. Y. Chen, D. A. Rey, F. W. Wise, and C. A. Batt, “Near-infrared fluorescence imaging with water-soluble lead salt quantum dots,” Journal of Physical Chemistry B, vol. 111, no. 20, pp. 5726–5730, 2007.
[68]
H. Li, W. Y. Shih, and W. H. Shih, “Synthesis and characterization of aqueous carboxyl-capped CdS quantum dots for bioapplications,” Industrial and Engineering Chemistry Research, vol. 46, no. 7, pp. 2013–2019, 2007.
[69]
J. K. Jaiswal, H. Mattoussi, J. M. Mauro, and S. M. Simon, “Long-term multiple color imaging of live cells using quantum dot bioconjugates,” Nature Biotechnology, vol. 21, no. 1, pp. 47–51, 2002.
[70]
S. L. Gac, I. Vermes, and A. V. D. Berg, “Quantum dots based probes conjugated to annexin V for photostable apoptosis detection and imaging,” Nano Letters, vol. 6, no. 9, pp. 1863–1869, 2006.
[71]
A. Wolcott, D. Gerion, M. Visconte et al., “Silica-coated CdTe quantum dots functionalized with thiols for bioconjugation to IgG proteins,” Journal of Physical Chemistry B, vol. 110, no. 11, pp. 5779–5789, 2006.
[72]
H. W. Duan and S. M. Nie, “Cell-penetrating quantum dots based on multivalent and endosome-disrupting surface coatings,” Journal of the American Chemical Society, vol. 129, no. 11, pp. 3333–3336, 2007.
[73]
A. Liu, S. Peng, J. C. Soo, M. Kuang, P. Chen, and H. Duan, “Quantum dots with phenylboronic acid tags for specific labeling of sialic acids on living cells,” Analytical Chemistry, vol. 83, no. 3, pp. 1124–1130, 2011.
[74]
F. Q. Chen and D. Gerion, “Fluorescent CdSe/ZnS nanocrystal-peptide conjugates for long-term, nontoxic imaging and nuclear targeting in living cells,” Nano Letters, vol. 4, no. 10, pp. 1827–1832, 2004.
[75]
I. Yildiz, B. McCaughan, S. F. Cruickshank, J. F. Callan, and F. M. Raymo, “Biocompatible CdSe-ZnS Core-shell quantum dots coated with hydrophilic polythiols,” Langmuir, vol. 25, no. 12, pp. 7090–7096, 2009.
[76]
G. Ruan, A. Agrawal, A. I. Marcus, and S. M. Nie, “Imaging and tracking of Tat peptide-conjugated quantum dots in living cells: new insights into nanoparticle uptake, intracellular transport, and vesicle shedding,” Journal of the American Chemical Society, vol. 129, no. 47, pp. 14759–14766, 2007.
[77]
R. Wilson, D. G. Spiller, A. Beckett, I. A. Prior, and V. Sée, “Highly stable dextran-coated quantum dots for biomolecular detection and cellular imaging,” Chemistry of Materials, vol. 22, no. 23, pp. 6361–6369, 2010.
[78]
N. Ma, J. Yang, K. M. Stewart, and S. O. Kelley, “DNA-passivated CdS nanocrystals: luminescence, bioimaging, and toxicity profiles,” Langmuir, vol. 23, no. 26, pp. 12783–12787, 2007.
[79]
P. Liu, Q. S. Wang, and X. Li, “Studies on CdSe/L-cysteine quantum dots synthesized in aqueous solution for biological labeling,” Journal of Physical Chemistry C, vol. 113, no. 18, pp. 7670–7676, 2009.
[80]
C. F. Wu, T. Schneider, M. Zeigler et al., “Bioconjugation of ultrabright semiconducting polymer dots for specific cellular targeting,” Journal of the American Chemical Society, vol. 132, no. 43, pp. 15410–15417, 2010.
[81]
P. M. Allen, W. H. Liu, V. P. Chauhan et al., “InAs(ZnCdS) auantum dots optimized for biological imaging in the near-infrared,” Journal of the American Chemical Society, vol. 132, no. 2, pp. 470–471, 2010.
[82]
S. Prabakar, A. Shiohara, S. Hanada, K. Fujioka, K. Yamamoto, and R. D. Tilley, “Size controlled synthesis of germanium nanocrystals by hydride reducing agents and their biological applications,” Chemistry of Materials, vol. 22, no. 2, pp. 482–486, 2010.
[83]
P. Sun, H. Y. Zhang, C. Liu et al., “Preparation and characterization of Fe3O4/CdTe magnetic/fluorescent nanocomposites and their applications in immuno-labeling and fluorescent imaging of cancer cells,” Langmuir, vol. 26, no. 2, pp. 1278–1284, 2010.
[84]
W. J. M. Mulder, R. Koole, R. J. Brandwijk et al., “Quantum dots with a paramagnetic coating as a bimodal molecular imaging probe,” Nano Letters, vol. 6, no. 1, pp. 1–6, 2006.
[85]
V. Bagalkot, L. F. Zhang, E. Levy-Nissenbaum et al., “Quantum dot-aptamer conjugates for synchronous cancer imaging, therapy, and sensing of drug delivery based on Bi-fluorescence resonance energy transfer,” Nano Letters, vol. 7, no. 10, pp. 3065–3070, 2007.
[86]
J. Qian, K. T. Yong, I. Roy et al., “Imaging pancreatic cancer using surface-functionalized quantum dots,” Journal of Physical Chemistry B, vol. 111, no. 25, pp. 6969–6972, 2007.
[87]
F. Erogbogbo, K. T. Yong, I. Roy, G. X. Xu, P. N. Prasad, and M. T. Swihart, “Biocompatible luminescent silicon quantum dots for imaging of cancer cells,” ACS Nano, vol. 2, no. 5, pp. 873–878, 2008.
[88]
K. T. Yong, H. Ding, I. Roy et al., “Imaging pancreatic cancer using bioconjugated inp quantum dots,” ACS Nano, vol. 3, no. 3, pp. 502–510, 2009.
[89]
C. Walther, K. Meyer, R. Rennert, and I. Neundorf, “Quantum dot—carrier peptide conjugates suitable for imaging and delivery applications,” Bioconjugate Chemistry, vol. 19, no. 12, pp. 2346–2356, 2008.
[90]
V. Biju, D. Muraleedharan, K. I. Nakayama et al., “Quantum dot-insect neuropeptide conjugates for fluorescence imaging, transfection, and nucleus targeting of living cells,” Langmuir, vol. 23, no. 20, pp. 10254–10261, 2007.
[91]
K. C. Weng, C. O. Noble, B. Papahadjopoulos-Sternberg et al., “Targeted tumor cell internalization and imaging of multifunctional quantum dot-conjugated immunoliposomes in vitro and in vivo,” Nano Letters, vol. 8, no. 9, pp. 2851–2857, 2008.
[92]
R. R. Smith, Z. Cheng, A. De, A. L. Koh, R. Sinclair, and S. S. Gambhir, “Real-time intravital imaging of RGD-quantum dot binding to luminal endothelium in mouse tumor neovasculature,” Nano Letters, vol. 8, no. 9, pp. 2599–2606, 2008.
[93]
H. S. Choi, W. H. Liu, F. B. Liu et al., “Design considerations for tumour-targeted nanoparticles,” Nature Nanotechnology, vol. 5, no. 1, pp. 42–47, 2010.
[94]
A. Papagiannaros, J. Upponi, W. Hartner, D. Mongayt, T. Levchenko, and V. Torchilin, “Quantum dot loaded immunomicelles for tumor imaging,” BMC Medical Imaging, vol. 10, no. 1, article 22, 2010.
[95]
L. Li, T. J. Daou, I. Texier, T. T. K. Chi, N. Q. Liem, and P. Reiss, “Highly luminescent cuins 2/ZnS core-shell nanocrystals: cadmium-free quantum dots for in vivo imaging,” Chemistry of Materials, vol. 21, no. 12, pp. 2422–2429, 2009.
[96]
B. Dubertret, P. Skourides, D. J. Norris, V. Noireaux, A. H. Brivanlou, and A. Libchaber, “In vivo imaging of quantum dots encapsulated in phospholipid micelles,” Science, vol. 298, no. 5599, pp. 1759–1762, 2002.
[97]
B. Ballou, B. C. Lagerholm, L. A. Ernst, M. P. Bruchez, and A. S. Waggoner, “Noninvasive Imaging of quantum dots in mice,” Bioconjugate Chemistry, vol. 15, no. 1, pp. 79–86, 2004.
[98]
T. J. Daou, L. Li, P. Reiss, V. Josserand, and I. Texier, “Effect of poly(ethylene glycol) length on the in vivo behavior of coated quantum dots,” Langmuir, vol. 25, no. 5, pp. 3040–3044, 2009.
[99]
K. Yang, Y. A. Cao, C. Shi et al., “Quantum dot-based visual in vivo imaging for oral squamous cell carcinoma in mice,” Oral Oncology, vol. 46, no. 12, pp. 864–868, 2010.
[100]
E. Cassette, T. Pons, C. Bouet et al., “Synthesis and characterization of near-infrared Cu-In-Se/ZnS core/shell quantum dots for in vivo imaging,” Chemistry of Materials, vol. 22, no. 22, pp. 6117–6124, 2010.
[101]
K. T. Yong, R. Hu, I. Roy et al., “Tumor targeting and imaging in live animals with functionalized semiconductor quantum rods,” ACS Applied Materials & Interfaces, vol. 1, no. 3, pp. 710–719, 2009.
[102]
W. Zhang, Y. Yao, and Y. S. Chen, “Imaging and quantifying the morphology and nanoelectrical properties of quantum dot nanoparticles interacting with DNA,” Journal of Physical Chemistry C, vol. 115, no. 3, pp. 599–606, 2011.
[103]
Y. X. Huang, X. J. Zheng, L. L. Kang et al., “Quantum dots as a sensor for quantitative visualization of surface charges on single living cells with nano-scale resolution,” Biosensors and Bioelectronics, vol. 26, no. 5, pp. 2114–2118, 2011.
