The unique luminescent properties of new-generation synthetic nanomaterials, upconversion nanoparticles (UCNPs), enabled high-contrast optical biomedical imaging by suppressing the crowded background of biological tissue autofluorescence and evading high tissue absorption. This raised high expectations on the UCNP utilities for intracellular and deep tissue imaging, such as whole animal imaging. At the same time, the critical nonlinear dependence of the UCNP luminescence on the excitation intensity results in dramatic signal reduction at (~1 cm) depth in biological tissue. Here, we report on the experimental and theoretical investigation of this trade-off aiming at the identification of optimal application niches of UCNPs e.g. biological liquids and subsurface tissue layers. As an example of such applications, we report on single UCNP imaging through a layer of hemolyzed blood. To extend this result towards in vivo applications, we quantified the optical properties of single UCNPs and theoretically analyzed the prospects of single-particle detectability in live scattering and absorbing bio-tissue using a human skin model. The model predicts that a single 70-nm UCNP would be detectable at skin depths up to 400 μm, unlike a hardly detectable single fluorescent (fluorescein) dye molecule. UCNP-assisted imaging in the ballistic regime thus allows for excellent applications niches, where high sensitivity is the key requirement.
References
[1]
Hilderbrand SA, Weissleder R (2009) Near-Infrared Fluorescence: Application to In Vivo Molecular Imaging. Curr Opin Chem Biol 14: 9–71.
[2]
Patterson MS, Chance B, Wilson BC (1989) Time Resolved Reflectance and Transmittance for the Non-Invasive Measurement of Tissue Optical Properties. Appl Opt 28: 2331–2336.
[3]
Corlu A, Choe R, Durduran T, Rosen MA, Schweiger M, et al. (2007) Three-Dimensional In Vivo Fluorescence Diffuse Optical Tomography of Breast Cancer in Humans. Opt Express 15: 6696–6716.
[4]
Schaafsma BE, Mieog JSD, Hutteman M, van der VorstJR, Kuppen PJK, et al. (2011) The clinical use of indocyanine green as a near-infrared fluorescent contrast agent for image-guided oncologic surgery. J Surg Oncol 104: 323–332.
[5]
Heer S, K？mpe K, Güdel HU, Haase M (2004) Highly Efficient Multicolour Upconversion Emission in Transparent Colloids of Lanthanide-Doped NaYF4 Nanocrystals. Adv Mater 16: 2102–2105.
[6]
Yi G, Lu H, Zhao S, Ge Y, Yang W, et al. (2004) Synthesis, Characterization, and Biological Application of Size-controlled Nanocrystalline NaYF4: Yb, Er Infrared-to-Visible Up-Conversion Phosphors. Nano Lett 4: 2191–2196.
[7]
Resch-Genger U, Grabolle M, Cavaliere-Jaricot S, Nitschke R, Nann T (2008) Quantum Dots Versus Organic Dyes as Fluorescent Labels. Nat Methods 5: 763–775.
[8]
Mancini MC, Kairdolf BA, Smith AM, Nie S (2008) Oxidative Quenching and Degradation of Polymer-encapsulated Quantum Dots: New Insights Into the Long-Term Fate and Toxicity of Nanocrystals In Vivo. J Am Chem Soc 130: 10836–10837.
[9]
Liu K, Liu X, Zeng Q, Zhang Y, Tu L, et al. (2012) Covalently Assembled NIR Nanoplatform for Simultaneous Fluorescence Imaging and Photodynamic Therapy of Cancer Cells. ACS nano 6: 4054–4062.
[10]
Auzel F (2004) Upconversion and Anti-Stokes Processes With f and d Ions in Solids. Chem Rev 104: 139–174.
[11]
Xu CT, Svensson N, Axelsson J, Svenmarker P, Somesfalean G, et al. (2008) Autofluorescence Insensitive Imaging Using Upconverting Nanocrystals in Scattering Media. Appl Phys Lett 93: 171103.
[12]
Leblond F, Davis SC, Valdés PA, Pogue BW (2010) Pre-Clinical Whole-Body Fluorescence Imaging: Review of Instruments, Methods and Applications. J Photochem Photobiol, B 98: 77–94.
[13]
Liu Q, Sun Y, Yang T, Feng W, Li C, et al. (2011) Sub-10 nm Hexagonal Lanthanide-Doped NaLuF4 Upconversion Nanocrystals for Sensitive Bioimaging in Vivo. J Am Chem Soc 133: 17122–17125.
[14]
Vinegoni C, Razansky D, Hilderbrand SA, Shao F, Ntziachristos V, et al. (2009) Transillumination Fluorescence Imaging in Mice Using Biocompatible Upconverting Nanoparticles. Opt Lett 34: 2566–2568.
[15]
Page RH, Schaffers KI, Waide PA, Tassano JB, Payne SA, et al. (1998) Upconversion-pumped Luminescence Efficiency of Rare-Earth-doped Hosts Sensitized With Trivalent Ytterbium. JOSA B 15: 996–1008.
[16]
Suyver J, Aebischer A, Biner D, Gerner P, Grimm J, et al. (2005) Novel Materials Doped With Trivalent Lanthanides and Transition Metal Ions Showing Near-Infrared to Visible Photon Upconversion. Opt Mater 27: 1111–1130.
[17]
Hehlen MP, Frei G, Güdel HU (1994) Dynamics of infrared-to-visible upconversion in Cs3Lu2Br9: 1% Er3+. Phys Rev B 50: 16264.
[18]
Zipfel WR, Williams RM, Christie R, Nikitin AY, Hyman BT, et al. (2003) Live Tissue Intrinsic Emission Microscopy Using Multiphoton-excited Native Fluorescence and Second Harmonic Generation. Proc Natl Acad Sci U S A 100: 7075.
[19]
Wang F, Wang J, Liu X (2010) Direct Evidence of a Surface Quenching Effect on Size-Dependent Luminescence of Upconversion Nanoparticles. Angew Chem Int Ed 122: 7618–7622.
[20]
Kelf T, Sreenivasan V, Sun J, Kim E, Goldys E, et al. (2010) Non-Specific Cellular Uptake of Surface-Functionalized Quantum Dots. Nanotechnology 21: 285105.
[21]
Pichaandi J, Boyer JC, Delaney KR, van Veggel FCJM (2011) Two-Photon Upconversion Laser (Scanning and Wide Field) Microscopy using Ln3+-Doped NaYF4 Upconverting Nanocrystals A Critical Evaluation of their Performance and Potential in Bio-imaging. J Phys Chem C: 19054–19064.
[22]
Ostrowski AD, Chan EM, Gargas DJ, Katz EM, Han G, et al. (2012) Controlled Synthesis and Single Particle Imaging of Bright, Sub-10 nm Lanthanide-Doped Upconverting Nanocrystals. ACS nano 6: 2686–2692.
[23]
Mialon G, Türkcan S, Dantelle G, Collins DP, Hadjipanayi M, et al. (2010) High Up-Conversion Efficiency of YVO4: Yb, Er Nanoparticles in Water Down to the Single-Particle Level. J Phys Chem C: 22449–22454.
[24]
Wu S, Han G, Milliron DJ, Aloni S, Altoe V, et al. (2009) Non-blinking and Photostable Upconverted Luminescence from Single Lanthanide-Doped Nanocrystals. Proc Natl Acad Sci U S A 106: 10917–10921.
[25]
Park YI, Kim JH, Lee KT, Jeon KS, Na HB, et al. (2009) Nonblinking and nonbleaching upconverting nanoparticles as an optical imaging nanoprobe and T1 magnetic resonance imaging contrast agent. Adv Mater 21: 4467–4471.
[26]
Lakshminarayana G, Ruan J, Qiu J (2009) NIR Luminescence From Er-Yb, Bi-Yb and Bi-Nd Codoped Germanate Glasses for Optical Amplification. J Alloys Compd 476: 878–883.
[27]
Mai HX, Zhang YW, Si R, Yan ZG, Sun L, et al. (2006) High-Quality sodium rare-earth fluoride nanocrystals: controlled synthesis and optical properties. J Am Chem Soc 128: 6426–6436.
[28]
Kr？mer KW, Biner D, Frei G, Güdel HU, Hehlen MP, et al. (2004) Hexagonal Sodium Yttrium Fluoride Based Green and Blue Emitting Upconversion Phosphors. Chem Mater 16: 1244–1251.
[29]
Melhuish W, Zander M (1984) Nomenclature, Symbols, Units and Their Usage in Spectrochemical Analysis-VII. Molecular Absorption Spectroscopy, Ultraviolet and Visible (UV/VIS) Pure Appl Chem 56: 231–245.
[30]
Tikhomirov V, Adamo G, Nikolaenko A, Rodriguez V, Gredin P, et al. (2010) Cathodo-and photoluminescence in Yb3+ Er3+ Co-Doped PbF2 Nanoparticles. Opt Express 18: 8836–8846.
[31]
Boyer JC, Van Veggel FCJM (2010) Absolute Quantum Yield Measurements of Colloidal NaYF4: Er3+, Yb3+ Upconverting Nanoparticles. Nanoscale 2: 1417–1419.
[32]
Mai HX, Zhang YW, Sun LD, Yan CH (2007) Highly Efficient Multicolor Up-conversion Emissions and Their Mechanisms of Monodisperse NaYF4: Yb, Er Core and Core/Shell-Structured Nanocrystals. J Phys Chem C 111: 13721–13729.
[33]
Wang Y, Tu L, Zhao J, Sun Y, Kong X, et al. (2009) Upconversion Luminescence of β-NaYF4: Yb3+, Er3+@ β-NaYF4 Core/Shell Nanoparticles: Excitation Power Density and Surface Dependence. J Phys Chem C. 113: 7164–7169.
[34]
Pollnau M, Gamelin D, Lüthi S, Güdel H, Hehlen M (2000) Power Dependence of Upconversion Luminescence in Lanthanide and Transition-Metal-Ion Systems. Phys Rev B 61: 3337.
[35]
Shan J, Uddi M, Wei R, Yao N, Ju Y (2010) The Hidden Effects of Particle Shape and Criteria for Evaluating the Upconversion Luminescence of the Lanthanide Doped Nanophosphors. J Phys Chem C 114: 2452–2461.
[36]
(1931) Commission Internationale de l’Eclairage Proceedings. Cambridge, United Kingdom: Cambridge University Press.
[37]
Boerma EC, Mathura K, van der Voort P, Spronk P, Ince C (2005) Quantifying Bedside-derived Imaging of Microcirculatory Abnormalities in Septic Patients: A Prospective Validation Study. Crit Care 9: R601–R606.
[38]
Bollinger A, Frey J, J？ger K, Furrer J, Seglias J, et al. (1982) Patterns of Diffusion Through Skin Capillaries in Patients With Long-Term Diabetes. N Engl J Med 307: 1305–1310.
[39]
Dietterle S, Lademann J, R？wert-Huber HJ, Stockfleth E, Antoniou C, et al. (2008) In-Vivo Diagnosis and Non-Inasive Monitoring of Imiquimod 5% Cream for Non-Melanoma Skin Cancer Using Confocal Laser Scanning Microscopy. Laser Phys Lett 5: 752–759.
[40]
Hsiung PL, Hardy J, Friedland S, Soetikno R, Du CB, et al. (2008) Detection of colonic dysplasia in vivo using a targeted heptapeptide and confocal microendoscopy. Nat Med 14: 454–458.
[41]
Salomatina E, Jiang B, Novak J, Yaroslavsky AN (2006) Optical properties of normal and cancerous human skin in the visible and near-infrared spectral range. J Biomed Opt 11: 064026.
[42]
(2012) Standards Australia Limited/Standards New Zealand, AS/NZS 60825. Sydney, AU and Wellington, NZ: SAI Global Limited. 1–48 p.
[43]
Robbins MS, Hadwen BJ (2003) The noise performance of electron multiplying charge-coupled devices. IEEE Transactions on Electronic Devices 50: 1227–1232.
[44]
Bessey OA, Lowry OH, Love RH (1949) The Fluorimetric Measurement of the Nucleotides or Riboflavind and Their Concentration in Tissues. J Biol Chem 180: 755–769.
[45]
Magnor M, Dorn P, Rudolph W (2001) Simulation of confocal microscopy through scattering media with and without time gating. JOSA B 18: 1695–1700.
[46]
Islam SDM, Susdorf T, Penzkofer A, Hegemann P (2003) Fluorescence quenching of flavin adenine dinucleotide in aqueous solution by pH dependent isomerisation and photo-induced electron transfer. Chem Phys 295: 137–149.
[47]
Nam SH, Bae YM, Park YI, Kim JH, Kim HM, et al. (2011) Long-Term Real-Time Tracking of Lanthanide Ion Doped Upconverting Nanoparticles in Living Cells. Angew Chem 123: 6217–6221.
[48]
Dong N, Pedroni M, Piccinelli F, Conti G, Sbarbati A, et al. (2011) NIR-to-NIR Two-Photon Excited CaF2: Tm3+, Yb3+ Nanoparticles: Multifunctional Nanoprobes for Highly Penetrating Fluorescence Bio-Imaging. ACS nano 5: 8665–8671.
[49]
Xu CT, Svenmarker P, Liu H, Wu X, Messing ME, et al. (2012) High-Resolution Fluorescence Diffuse Optical Tomography Developed with Nonlinear Upconverting Nanoparticles. ACS nano: 4788–4795.
[50]
Yi GS, Chow GM (2007) Water-soluble NaYF4: Yb, Er (Tm)/NaYF4/polymer core/shell/shell nanoparticles with significant enhancement of upconversion fluorescence. Chem Mater 19: 341–343.
[51]
Chen G, Shen J, Ohulchanskyy TY, Patel NJ, Kutikov A, et al. (2012) (α-NaYbF4: Tm3+)/CaF2 Core/Shell Nanoparticles with Efficient Near-Infrared to Near-Infrared Upconversion for High-Contrast Deep Tissue Bioimaging. ACS nano: 8280–8287.
[52]
Tuchin VV, Xu X, Wang RK (2002) Dynamic optical coherence tomography in studies of optical clearing, sedimentation, and aggregation of immersed blood. Appl Opt 41: 258–271.
[53]
Zhan Q, Qian J, Liang H, Somesfalean G, Wang D, et al. (2011) Using 915-nm Laser Excited Tm3+/Er3+/Ho3+ Doped NaYbF4 Upconversion Nanoparticles for In Vitro and Deeper In Vivo Bioimaging Without Overheating Irradiation. ACS nano: 3744–3757.
[54]
Wang C, Cheng L, Xu H, Liu Z (2012) Towards whole-body imaging at the single cell level using ultra-sensitive stem cell labeling with oligo-arginine modified upconversion nanoparticles. Biomaterials.
[55]
Cheng L, Yang K, Zhang S, Shao M, Lee S, et al. (2010) Highly-sensitive multiplexed in vivo imaging using PEGylated upconversion nanoparticles. Nano Research 3: 722–732.
[56]
Sreenivasan VKA, Kim EJ, Goodchild AK, Connor M, Zvyagin AV (2012) Targeting somatostatin receptors using in situ-bioconjugated fluorescent nanoparticles. Nanomedicine in press.
[57]
Sreenivasan VKA, Stremovskiy OA, Kelf TA, Heblinski M, Goodchild AK, et al. (2011) Pharmacological Characterization of a Recombinant, Fluorescent Somatostatin Receptor Agonist. Bioconjugate Chem 22: 1768–1775.
Becker A, Hessenius C, Licha K, Ebert B, Sukowski U, et al. (2001) Receptor-targeted Optical Imaging of Tumors With Near-Infrared Fluorescent Ligands. Nat Biotechnol 19: 327–331.
[60]
Kim HR, Andrieux K, Gil S, Taverna M, Chacun H, et al. (2007) Translocation of poly (ethylene glycol-co-hexadecyl) cyanoacrylate nanoparticles into rat brain endothelial cells: role of apolipoproteins in receptor-mediated endocytosis. Biomacromolecules 8: 793–799.
[61]
Xie L, Qin Y, Chen H-Y (2013) Direct Fluorescent Measurement of Blood Potassium with Polymeric Optical Sensors Based on Upconverting Nanomaterials. Anal Chem. In press.
