Luminescent colloidal quantum dots (QDs) possess numerous advantages as fluorophores in biological applications. However, a principal challenge is how to retain the desirable optical properties of quantum dots in aqueous media while maintaining biocompatibility. Because QD photophysical properties are directly related to surface states, it is critical to control the surface chemistry that renders QDs biocompatible while maintaining electronic passivation. For more than a decade, investigators have used diverse strategies for altering the QD surface. This review summarizes the most successful approaches for preparing biocompatible QDs using various chemical ligands.
References
[1]
Miyawaki, A. Visualization of the spatial and temporal dynamics of intracellular signaling. Dev. Cell 2003, 4, 295–305.
[2]
Resch-Genger, U.; Grabolle, M.; Cavaliere-Jaricot, S.; Nitschke, R.; Nann, T. Quantum dots versus organic dyes as fluorescent labels. Nat. Methods 2008, 5, 763–775.
[3]
Sutherland, A.J. Quantum dots as luminescent probes in biological systems. Curr. Opin. Solid State Mater. Sci 2002, 6, 365–370.
[4]
Xing, Y.; Rao, J. Quantum dot bioconjugates for in vitro diagnostics & in vivo imaging. Cancer Biomark 2008, 4, 307–319.
[5]
Medintz, I.L.; Mattoussi, H.; Clapp, A.R. Potential clinical applications of quantum dots. Int. J. Nanomedicine 2008, 3, 151–167.
[6]
Michalet, X.; Pinaud, F.F.; Bentolila, L.A.; Tsay, J.M.; Doose, S.; Li, J.J.; Sundaresan, G.; Wu, A.M.; Gambhir, S.S.; Weiss, S. Quantum dots for live cells, in vivo imaging, and diagnostics. Science 2005, 307, 538–544.
[7]
Robel, I.; Subramanian, V.; Kuno, M.; Kamat, P.V. Quantum dot solar cells. Harvesting light energy with CdSe nanocrystals molecularly linked to mesoscopic TiO2 films. J. Am. Chem. Soc 2006, 128, 2385–2393.
Pellegrino, T.; Manna, L.; Kudera, S.; Liedl, T.; Koktysh, D.; Rogach, A.L.; Keller, S.; R？dler, J.; Natile, G.; Parak, W.J. Hydrophobic nanocrystals coated with an amphiphilic polymer shell: A general route to water soluble nanocrystals. Nano Lett 2004, 4, 703–707.
[10]
Doose, S.; Tsay, J.M.; Pinaud, F.; Weiss, S. Comparison of photophysical and colloidal properties of biocompatible semiconductor nanocrystals using fluorescence correlation spectroscopy. Anal. Chem 2005, 77, 2235–2242.
[11]
Spanhel, L.; Haase, M.; Weller, H.; Henglein, A. Photochemistry of colloidal semiconductors. 20. Surface modification and stability of strong luminescing CdS particles. J. Am. Chem. Soc 1987, 109, 5649–5655.
[12]
Vinayaka, A.C.; Thakur, M.S. Photo-absorption and resonance energy transfer phenomenon in CdTe-protein bioconjugates: An insight towards QD-biomolecular interactions. Bioconjugate Chem 2011, 22, 968–975.
[13]
Talapin, D.V.; Rogach, A.L.; Shevchenko, E.V.; Kornowski, A.; Haase, M.; Weller, H. Dynamic distribution of growth rates within the ensembles of colloidal II–VI and III–V semiconductor nanocrystals as a factor governing their photoluminescence efficiency. J. Am. Chem. Soc 2002, 124, 5782–5790.
[14]
Rogach, A.L.; Harrison, M.T.; Kershaw, S.V.; Kornowski, A.; Burt, M.G.; Eychmüller, A.; Weller, H. Colloidally prepared CdHgTe and HgTe quantum dots with strong near-infrared luminescence. Phys. Stat. Sol. B 2001, 224, 153–158.
[15]
Bao, H.; Wang, E.; Dong, S. One-pot synthesis of cdte nanocrystals and shape control of luminescent CdTe–cystine nanocomposites. Small 2006, 2, 476–480.
[16]
Gaponik, N.; Talapin, D.V.; Rogach, A.L.; Hoppe, K.; Shevchenko, E.V.; Kornowski, A.; Eychmüller, A.; Weller, H. Thiol-capping of CdTe nanocrystals: An alternative to organometallic synthetic routes. J. Phys. Chem. B 2002, 106, 7177–7185.
[17]
Bao, H.; Gong, Y.; Li, Z.; Gao, M. Enhancement effect of illumination on the photoluminescence of water-soluble CdTe nanocrystals: Toward highly fluorescent CdTe/CdS core？shell structure. Chem. Mater 2004, 16, 3853–3859.
[18]
Zheng, Y.; Gao, S.; Ying, J.Y. Synthesis and cell-imaging applications of glutathione-capped CdTe quantum dots. Adv. Mater 2007, 19, 376–380.
[19]
Negishi, Y.; Nobusada, K.; Tsukuda, T. Glutathione-protected gold clusters revisited: Bridging the gap between gold(I)？thiolate complexes and thiolate-protected gold nanocrystals. J. Am. Chem. Soc 2005, 127, 5261–5270.
[20]
Barglik-Chory, C.; Remenyi, C.; Strohm, H.; Müller, G. Adjustment of the band gap energies of biostabilized CdS nanoparticles by application of statistical design of experiments. J. Phys. Chem. B 2004, 108, 7637–7640.
[21]
B？umle, M.; Stamou, D.; Segura, J.-M.; Hovius, R.; Vogel, H. Highly fluorescent streptavidin-coated CdSe nanoparticles: Preparation in water, characterization, and micropatterning. Langmuir 2004, 20, 3828–3831.
[22]
Qian, H.; Dong, C.; Weng, J.; Ren, J. Facile one-pot synthesis of luminescent, water-soluble, and biocompatible glutathione-coated CdTe nanocrystals. Small 2006, 2, 747–751.
[23]
Wei, S.; Lu, J.; Yu, W.C.; Qian, Y.T. InP nanocrystals via surfactant-aided hydrothermal synthesis. J. Appl. Phys 2004, 95, 3683–3688.
[24]
Li, C.; Ando, M.; Enomoto, H.; Murase, N. Highly luminescent water-soluble InP/ZnS nanocrystals prepared via reactive phase transfer and photochemical processing. J. Phys. Chem. C 2008, 112, 20190–20199.
[25]
Skaff, H.; Emrick, T. The use of 4-substituted pyridines to afford amphiphilic, pegylated cadmium selenide nanoparticlesElectronic supplementary information (ESI) available: TEM images and absorbance profiles. Chem. Commun 2003, 52–53, doi:10.1039/B208718A. Available online: http://www.rsc.org/suppdata/cc/b2/b208718a/ (accessed on 9/14/2011).
[26]
Locklin, J.; Patton, D.; Deng, S.; Baba, A.; Millan, M.; Advincula, R.C. Conjugated oligothiophene-dendron-capped CdSe nanoparticles: Synthesis and energy transfer. Chem. Mater 2004, 16, 5187–5193.
[27]
Liu, Y.; Kim, M.; Wang, Y.; Wang, Y.A.; Peng, X. Highly luminescent, stable, and water-soluble CdSe/CdS core？shell dendron nanocrystals with carboxylate anchoring groups. Langmuir 2006, 22, 6341–6345.
[28]
Ren, T.; Mandal, P.K.; Erker, W.; Liu, Z.; Avlasevich, Y.; Puhl, L.; Müllen, K.; Basché, T. A simple and versatile route to stable quantum dot-dye hybrids in nonaqueous and aqueous solutions. J. Am. Chem. Soc 2008, 130, 17242–17243.
[29]
Chan, W.C.W.; Nie, S. Quantum dot bioconjugates for ultrasensitive nonisotopic detection. Science 1998, 281, 2016–2018.
[30]
Tetsuka, H.; Ebina, T.; Mizukami, F. Highly luminescent flexible quantum dot-clay films. Adv. Mater 2008, 20, 3039–3043.
[31]
Mitchell, G.P.; Mirkin, C.A.; Letsinger, R.L. Programmed assembly of DNA functionalized quantum dots. J. Am. Chem. Soc 1999, 121, 8122–8123.
Hanaki, K.; Momo, A.; Oku, T.; Komoto, A.; Maenosono, S.; Yamaguchi, Y.; Yamamoto, K. Semiconductor quantum dot/albumin complex is a long-life and highly photostable endosome marker. Biochem. Bioph. Res. Commun 2003, 302, 496–501.
[34]
Chen, C.-C.; Yet, C.-P.; Wang, H.-N.; Chao, C.-Y. Self-assembly of monolayers of cadmium selenide nanocrystals with dual color emission. Langmuir 1999, 15, 6845–6850.
[35]
Babu, P.; Sinha, S.; Surolia, A. Sugar-quantum dot conjugates for a selective and sensitive detection of lectins. Bioconjugate Chem 2007, 18, 146–151.
[36]
Charvet, N.; Reiss, P.; Roget, A.; Dupuis, A.; Grunwald, D.; Carayon, S.; Chandezon, F.; Livache, T. Biotinylated CdSe/ZnSe nanocrystals for specific fluorescent labeling. J. Mater. Chem 2004, 14, 2638–2642.
[37]
Wang, Y.A.; Li, J.J.; Chen, H.; Peng, X. Stabilization of inorganic nanocrystals by organic dendrons. J. Am. Chem. Soc 2002, 124, 2293–2298.
[38]
Guo, W.; Li, J.J.; Wang, Y.A.; Peng, X. Luminescent CdSe/CdS Core/Shell nanocrystals in dendron boxes: Superior chemical, photochemical and thermal stability. J. Am. Chem. Soc 2003, 125, 3901–3909.
[39]
Liu, W.; Choi, H.S.; Zimmer, J.P.; Tanaka, E.; Frangioni, J.V.; Bawendi, M. Compact cysteine-coated CdSe(ZnCdS) quantum dots for in vivo applications. J. Am. Chem. Soc 2007, 129, 14530–14531.
[40]
Sukhanova, A.; Venteo, L.; Devy, J.; Artemyev, M.; Oleinikov, V.; Pluot, M.; Nabiev, I. Highly stable fluorescent nanocrystals as a novel class of labels for immunohistochemical analysis of paraffin-embedded tissue sections. Lab. Invest 2002, 82, 1259–1261.
Aldana, J.; Lavelle, N.; Wang, Y.; Peng, X. Size-dependent dissociation ph of thiolate ligands from cadmium chalcogenide nanocrystals. J. Am. Chem. Soc 2005, 127, 2496–2504.
[43]
Breus, V.V.; Heyes, C.D.; Nienhaus, G.U. Quenching of CdSe-ZnS core-shell quantum dot luminescence by water-soluble thiolated ligands. J. Phys. Chem. C 2007, 111, 18589–18594.
[44]
Pong, B.-K.; Trout, B.L.; Lee, J.-Y. Modified ligand-exchange for efficient solubilization of CdSe/ZnS quantum dots in water: A procedure guided by computational studies. Langmuir 2008, 24, 5270–5276.
[45]
Wang, Q.; Xu, Y.; Zhao, X.; Chang, Y.; Liu, Y.; Jiang, L.; Sharma, J.; Seo, D.-K.; Yan, H. A facile one-step in situ functionalization of quantum dots with preserved photoluminescence for bioconjugation. J. Am. Chem. Soc 2007, 129, 6380–6381.
[46]
Tamang, S.; Beaune, G.; Poillot, C.; de Waard, M.; Texier-Nogues, I.; Reiss, P. Compact and highly stable quantum dots through optimized aqueous phase transfer. In SPIE Photonics West BIOS session, Proceedings of SPIE; SPIE: San Francisco, CA, USA, 2011; pp. 79091B–79091B-6.
[47]
Schapotschnikow, P.; Hommersom, B.; Vlugt, T.J.H. Adsorption and binding of ligands to CdSe nanocrystals. J. Phys. Chem. C 2009, 113, 12690–12698.
[48]
Jeong, S.; Achermann, M.; Nanda, J.; Ivanov, S.; Klimov, V.I.; Hollingsworth, J.A. Effect of the thiol-thiolate equilibrium on the photophysical properties of aqueous CdSe/ZnS nanocrystal quantum dots. J. Am. Chem. Soc 2005, 127, 10126–10127.
[49]
Sukhanova, A.; Devy, J.; Venteo, L.; Kaplan, H.; Artemyev, M.; Oleinikov, V.; Klinov, D.; Pluot, M.; Cohen, J.H.M.; Nabiev, I. Biocompatible fluorescent nanocrystals for immunolabeling of membrane proteins and cells. Anal. Biochem 2004, 324, 60–67.
[50]
Jiang, W.; Mardyani, S.; Fischer, H.; Chan, W.C.W. Design and characterization of lysine cross-linked mercapto-acid biocompatible quantum dots. Chem. Mater 2006, 18, 872–878.
Breus, V.V.; Heyes, C.D.; Tron, K.; Nienhaus, G.U. Zwitterionic biocompatible quantum dots for wide pH stability and weak nonspecific binding to cells. ACS Nano 2009, 3, 2573–2580.
[53]
Mattoussi, H.; Mauro, J.M.; Goldman, E.R.; Anderson, G.P.; Sundar, V.C.; Mikulec, F.V.; Bawendi, M.G. Self-assembly of CdSe-ZnS quantum dot bioconjugates using an engineered recombinant protein. J. Am. Chem. Soc 2000, 122, 12142–12150.
[54]
Susumu, K.; Mei, B.C.; Mattoussi, H. Multifunctional ligands based on dihydrolipoic acid and polyethylene glycol to promote biocompatibility of quantum dots. Nat. Protoc 2009, 4, 424–436.
[55]
Susumu, K.; Uyeda, H.T.; Medintz, I.L.; Pons, T.; Delehanty, J.B.; Mattoussi, H. Enhancing the stability and biological functionalities of quantum dots via compact multifunctional ligands. J. Am. Chem. Soc 2007, 129, 13987–13996.
[56]
Clapp, A.R.; Medintz, I.L.; Fisher, B.R.; Anderson, G.P.; Mattoussi, H. Can luminescent quantum dots be efficient energy acceptors with organic dye donors? J. Am. Chem. Soc 2005, 127, 1242–1250.
[57]
Clapp, A.R.; Medintz, I.L.; Uyeda, H.T.; Fisher, B.R.; Goldman, E.R.; Bawendi, M.G.; Mattoussi, H. Quantum dot-based multiplexed fluorescence resonance energy transfer. J. Am. Chem. Soc 2005, 127, 18212–18221.
[58]
Clapp, A.R.; Goldman, E.R.; Mattoussi, H. Capping of CdSe–ZnS quantum dots with DHLA and subsequent conjugation with proteins. Nat. Protoc 2006, 1, 1258–1266.
[59]
Howarth, M.; Liu, W.; Puthenveetil, S.; Zheng, Y.; Marshall, L.F.; Schmidt, M.M.; Wittrup, K.D.; Bawendi, M.G.; Ting, A.Y. Monovalent, reduced-size quantum dots for imaging receptors on living cells. Nat. Methods 2008, 5, 397–399.
[60]
Susumu, K.; Medintz, I.L.; Delehanty, J.B.; Boeneman, K.; Mattoussi, H. Modification of poly(ethylene glycol)-capped quantum dots with nickel nitrilotriacetic acid and self-assembly with histidine-tagged proteins. J. Phys. Chem. C 2010, 114, 13526–13531.
[61]
Medintz, I.L.; Stewart, M.H.; Trammell, S.A.; Susumu, K.; Delehanty, J.B.; Mei, B.C.; Melinger, J.S.; Blanco-Canosa, J.B.; Dawson, P.E.; Mattoussi, H. Quantum-dot/dopamine bioconjugates function as redox coupled assemblies for in vitro and intracellular pH sensing. Nat. Mater 2010, 9, 676–684.
[62]
Kikkeri, R.; Lepenies, B.; Adibekian, A.; Laurino, P.; Seeberger, P.H. In vitro imaging and in vivo liver targeting with carbohydrate capped quantum dots. J. Am. Chem. Soc 2009, 131, 2110–2112.
[63]
Uyeda, H.T.; Medintz, I.L.; Jaiswal, J.K.; Simon, S.M.; Mattoussi, H. Synthesis of compact multidentate ligands to prepare stable hydrophilic quantum dot fluorophores. J. Am. Chem. Soc 2005, 127, 3870–3878.
[64]
Pathak, S.; Choi, S.-K.; Arnheim, N.; Thompson, M.E. Hydroxylated quantum dots as luminescent probes for in situ hybridization. J. Am. Chem. Soc 2001, 123, 4103–4104.
[65]
Palaniappan, K.; Hackney, S.A.; Liu, J. Supramolecular control of complexation-induced fluorescence change of water-soluble, β-cyclodextrin-modified CdS quantum dots. Chem. Commun 2004, 2704–2705. supply the doi if there is no volume.
[66]
Liu, D.; Snee, P.T. Water-soluble semiconductor nanocrystals cap exchanged with metalated ligands. ACS Nano 2011, 5, 546–550.
[67]
Querner, C.; Reiss, P.; Bleuse, J.; Pron, A. Chelating ligands for nanocrystals’ surface functionalization. J. Am. Chem. Soc 2004, 126, 11574–11582.
[68]
Querner, C.; Benedetto, A.; Demadrille, R.; Rannou, P.; Reiss, P. Carbodithioate-Containing oligo- and polythiophenes for nanocrystals’ surface functionalization. Chem. Mater 2006, 18, 4817–4826.
[69]
Dubois, F.; Mahler, B.; Dubertret, B.; Doris, E.; Mioskowski, C. A versatile strategy for quantum dot ligand exchange. J. Am. Chem. Soc 2007, 129, 482–483.
Kim, S.; Bawendi, M.G. Oligomeric ligands for luminescent and stable nanocrystal quantum dots. J. Am. Chem. Soc 2003, 125, 14652–14653.
[72]
Wang, M.; Oh, J.K.; Dykstra, T.E.; Lou, X.; Scholes, G.D.; Winnik, M.A. Surface modification of CdSe and CdSe/ZnS semiconductor nanocrystals with poly(N,N-dimethylaminoethyl methacrylate). Macromolecules 2006, 39, 3664–3672.
[73]
Wang, M.; Felorzabihi, N.; Guerin, G.; Haley, J.C.; Scholes, G.D.; Winnik, M.A. Water-soluble CdSe quantum dots passivated by a multidentate diblock copolymer. Macromolecules 2007, 40, 6377–6384.
[74]
Wang, X.-S.; Dykstra, T.E.; Salvador, M.R.; Manners, I.; Scholes, G.D.; Winnik, M.A. Surface passivation of luminescent colloidal quantum dots with poly(dimethylaminoethyl methacrylate) through a ligand exchange process. J. Am. Chem. Soc 2004, 126, 7784–7785.
[75]
Kairdolf, B.A.; Mancini, M.C.; Smith, A.M.; Nie, S. Minimizing nonspecific cellular binding of quantum dots with hydroxyl-derivatized surface coatings. Anal. Chem 2008, 80, 3029–3034.
[76]
Smith, A.M.; Duan, H.; Rhyner, M.N.; Ruan, G.; Nie, S. A systematic examination of surface coatings on the optical and chemical properties of semiconductor quantum dots. Phys. Chem. Chem. Phys 2006, 8, 3895–3903.
[77]
Pons, T.; Uyeda, H.T.; Medintz, I.L.; Mattoussi, H. Hydrodynamic dimensions, electrophoretic mobility, and stability of hydrophilic quantum dots. J. Phys. Chem. B 2006, 110, 20308–20316.
[78]
Pellegrino, T.; Manna, L.; Kudera, S.; Liedl, T.; Koktysh, D.; Rogach, A.L.; Keller, S.; R？dler, J.; Natile, G.; Parak, W.J. Hydrophobic nanocrystals coated with an amphiphilic polymer shell: A general route to water soluble nanocrystals. Nano Lett 2004, 4, 703–707.
[79]
Smith, A.M.; Nie, S. Minimizing the hydrodynamic size of quantum dots with multifunctional multidentate polymer ligands. J. Am. Chem. Soc 2008, 130, 11278–11279.
[80]
Stewart, M.H.; Susumu, K.; Mei, B.C.; Medintz, I.L.; Delehanty, J.B.; Blanco-Canosa, J.B.; Dawson, P.E.; Mattoussi, H. Multidentate poly(ethylene glycol) ligands provide colloidal stability to semiconductor and metallic nanocrystals in extreme conditions. J. Am. Chem. Soc 2010, 132, 9804–9813.
[81]
Gerion, D.; Pinaud, F.; Williams, S.C.; Parak, W.J.; Zanchet, D.; Weiss, S.; Alivisatos, A.P. Synthesis and properties of biocompatible water-soluble silica-coated CdSe/ZnS semiconductor quantum dots. J. Phys. Chem. B 2001, 105, 8861–8871.
[82]
Fu, A.; Gu, W.; Boussert, B.; Koski, K.; Gerion, D.; Manna, L.; Le Gros, M.; Larabell, C.A.; Alivisatos, A.P. Semiconductor quantum rods as single molecule fluorescent biological labels. Nano Lett 2007, 7, 179–182.
[83]
Parak, W.J.; Gerion, D.; Zanchet, D.; Woerz, A.S.; Pellegrino, T.; Micheel, C.; Williams, S.C.; Seitz, M.; Bruehl, R.E.; Bryant, Z.; et al. Conjugation of DNA to silanized colloidal semiconductor nanocrystalline quantum dots. Chem. Mater 2002, 14, 2113–2119.
[84]
Darbandi, M.; Thomann, R.; Nann, T. Single quantum dots in silica spheres by microemulsion synthesis. Chem. Mater 2005, 17, 5720–5725.
[85]
Kim, J.; Lee, J.E.; Lee, J.; Yu, J.H.; Kim, B.C.; An, K.; Hwang, Y.; Shin, C.-H.; Park, J.-G.; Kim, J.; Hyeon, T. Magnetic fluorescent delivery vehicle using uniform mesoporous silica spheres embedded with monodisperse magnetic and semiconductor nanocrystals. J. Am. Chem. Soc 2006, 128, 688–689.
[86]
Yi, D.K.; Selvan, S.T.; Lee, S.S.; Papaefthymiou, G.C.; Kundaliya, D.; Ying, J.Y. Silica-coated nanocomposites of magnetic nanoparticles and quantum dots. J. Am. Chem. Soc 2005, 127, 4990–4991.
[87]
Nann, T.; Mulvaney, P. Single quantum dots in spherical silica particles. Angew. Chem. Int. Ed 2004, 43, 5393–5396.
[88]
Chen, Y.; Rosenzweig, Z. Luminescent CdSe quantum dot doped stabilized micelles. Nano Lett 2002, 2, 1299–1302.
[89]
St？ber, W.; Fink, A.; Bohn, E. Controlled growth of monodisperse silica spheres in the micron size range. J. Colloid Interface Sci 1968, 26, 62–69.
[90]
Dubertret, B. In vivo imaging of quantum dots encapsulated in phospholipid micelles. Science 2002, 298, 1759–1762.
Lala, N.; Lalbegi, S.P.; Adyanthaya, S.D.; Sastry, M. Phase transfer of aqueous gold colloidal particles capped with inclusion complexes of cyclodextrin and alkanethiol molecules into chloroform. Langmuir 2001, 17, 3766–3768.
[93]
Wang, Y.; Wong, J.F.; Teng, X.; Lin, X.Z.; Yang, H. “Pulling” nanoparticles into water: Phase transfer of oleic acid stabilized monodisperse nanoparticles into aqueous solutions of α-cyclodextrin. Nano Lett 2003, 3, 1555–1559.
[94]
Shen, L.; Laibinis, P.E.; Hatton, T.A. Bilayer surfactant stabilized magnetic fluids: Synthesis and interactions at interfaces. Langmuir 1999, 15, 447–453.
[95]
Swami, A.; Kumar, A.; Sastry, M. Formation of water-dispersible gold nanoparticles using a technique based on surface-bound interdigitated bilayers. Langmuir 2003, 19, 1168–1172.
[96]
Yu, W.W.; Chang, E.; Falkner, J.C.; Zhang, J.; Al-Somali, A.M.; Sayes, C.M.; Johns, J.; Drezek, R.; Colvin, V.L. Forming biocompatible and nonaggregated nanocrystals in water using amphiphilic polymers. J. Am. Chem. Soc 2007, 129, 2871–2879.
[97]
Wu, X.; Liu, H.; Liu, J.; Haley, K.N.; Treadway, J.A.; Larson, J.P.; Ge, N.; Peale, F.; Bruchez, M.P. Immunofluorescent labeling of cancer marker Her2 and other cellular targets with semiconductor quantum dots. Nat. Biotech 2003, 21, 41–46.
Mattoussi, H.; Mauro, J.M.; Goldman, E.R.; Anderson, G.P.; Sundar, V.C.; Mikulec, F.V.; Bawendi, M.G. Self-assembly of CdSe？ZnS quantum dot bioconjugates using an engineered recombinant protein. J. Am. Chem. Soc 2000, 122, 12142–12150.
[107]
Howarth, M.; Takao, K.; Hayashi, Y.; Ting, A.Y. Targeting quantum dots to surface proteins in living cells with biotin ligase. Proc. Natl. Acad. Soc. USA 2005, 102, 7583–7588.
