Tumor eradication at depth.Substituted difuranonaphtalene Substituted distyryl benzene Dendritic dimers around the PS Modified bare tetrapyrroles PyP yPyyPy Porphycenes PdTPPo TPPo Conjugated porphyrin dimers Symmetric squaraines derivatives Quadrupolar chromophores Gold Nanorods Coumarin-based PS Porphyrin triphenylamine Diketopyrrolopyrrole porphyrine conjugates DPP-ZnP DPP-ZnP-DPP[71]887[72] [73]770 916 806 800 835 820[74] [75] [76] [77] [78] [79] [80]20000.58 0.[81]TP excited nano-transducer for PDTIn addition to developing new PSs with high TP absorption cross-sections, there has been an increased interest in using energy transducers to locally absorb incident NIR radiation to subsequently activate the PS. In most cases, NIR radiation is absorbed through TP processes by a nanotransducer (Fig. 5A2) that could have various origins. One option is to link the PS to chromophores that have strong TP absorption cross-sections. Under NIR radiation, the chromophores will be excited by multi-photon processes and will transfer part of the excitation energy to the PS by FRET. Bhawalkar et al. demonstrated that conjugating the PS to chromophores did not modify the photochemical properties of the PS, and demonstrated the Brefeldin A chemical information ability for the linked PS to generate 1O2 [82]. Later, several studies were GW0742 site published that validated the concept of antenna chromophores, i.e. chromophores that activate the PS through FRET transfer following TP excitation [83-85]. Instead of chemically linking the PS to the chromophores, strategies that co-encapsulate them into silica nanoparticles (NPs) have also been proposed [86]. To improve the efficiency of the indirect activation of PDT with TP excitation nanoparticles, plasmonic gold nanorods (GNR) with higher TP absorption cross-sections can be used. Zhao et al. demonstrated enhanced 1O2 generation by using GNR combined with a porphyrin (T790) as PS [87].Upconverting Nanoparticles (UCNP)Up-converting nanoparticles (UNCPs) are promising candidates for deep tissue PDT and have been extensively studied over the past few years [4, 93]. UCNPs are usually made of a ceramic lattice doped with rare earth ions that allow for sequential absorption of two photons through a metastable energy level. The lifetime of the metastable state is typically on the order of a microsecond, and is an order of magnitude longer than the lifetime of virtual states involved in TP processes. A consequence of the longer lifetime of the transitional state includes the possibility to use continuous wave lasers and, more importantly, lower power densities for UNCP excitation. For example, the power densities may be in the range of 1-103 W.cm-2 for UNCP excitation,http://www.thno.orgTheranostics 2016, Vol. 6, Issuewhereas 106-109 W.cm2 are required for TP activation. Typically, after the absorption of two or more low energy NIR photons (usually around 980 nm) by UNCPs, a single higher energy photon is emitted in the visible range (Fig. 5A3). Since this process does not naturally occur in living systems, imaging rare earth materials through upconversion emission results in very low non-specific background for fluorescence and PDT, as is reviewed thoroughly by Moghe et al [94]. We will not go into details for this type of transducers because excellent and more exhaustive reviews have already been published on the subject [4, 93]. However, the large amount of in vitro and in vivo studies reporting an efficient UCNP induced PDT effect substantiate the promi.Tumor eradication at depth.Substituted difuranonaphtalene Substituted distyryl benzene Dendritic dimers around the PS Modified bare tetrapyrroles PyP yPyyPy Porphycenes PdTPPo TPPo Conjugated porphyrin dimers Symmetric squaraines derivatives Quadrupolar chromophores Gold Nanorods Coumarin-based PS Porphyrin triphenylamine Diketopyrrolopyrrole porphyrine conjugates DPP-ZnP DPP-ZnP-DPP[71]887[72] [73]770 916 806 800 835 820[74] [75] [76] [77] [78] [79] [80]20000.58 0.[81]TP excited nano-transducer for PDTIn addition to developing new PSs with high TP absorption cross-sections, there has been an increased interest in using energy transducers to locally absorb incident NIR radiation to subsequently activate the PS. In most cases, NIR radiation is absorbed through TP processes by a nanotransducer (Fig. 5A2) that could have various origins. One option is to link the PS to chromophores that have strong TP absorption cross-sections. Under NIR radiation, the chromophores will be excited by multi-photon processes and will transfer part of the excitation energy to the PS by FRET. Bhawalkar et al. demonstrated that conjugating the PS to chromophores did not modify the photochemical properties of the PS, and demonstrated the ability for the linked PS to generate 1O2 [82]. Later, several studies were published that validated the concept of antenna chromophores, i.e. chromophores that activate the PS through FRET transfer following TP excitation [83-85]. Instead of chemically linking the PS to the chromophores, strategies that co-encapsulate them into silica nanoparticles (NPs) have also been proposed [86]. To improve the efficiency of the indirect activation of PDT with TP excitation nanoparticles, plasmonic gold nanorods (GNR) with higher TP absorption cross-sections can be used. Zhao et al. demonstrated enhanced 1O2 generation by using GNR combined with a porphyrin (T790) as PS [87].Upconverting Nanoparticles (UCNP)Up-converting nanoparticles (UNCPs) are promising candidates for deep tissue PDT and have been extensively studied over the past few years [4, 93]. UCNPs are usually made of a ceramic lattice doped with rare earth ions that allow for sequential absorption of two photons through a metastable energy level. The lifetime of the metastable state is typically on the order of a microsecond, and is an order of magnitude longer than the lifetime of virtual states involved in TP processes. A consequence of the longer lifetime of the transitional state includes the possibility to use continuous wave lasers and, more importantly, lower power densities for UNCP excitation. For example, the power densities may be in the range of 1-103 W.cm-2 for UNCP excitation,http://www.thno.orgTheranostics 2016, Vol. 6, Issuewhereas 106-109 W.cm2 are required for TP activation. Typically, after the absorption of two or more low energy NIR photons (usually around 980 nm) by UNCPs, a single higher energy photon is emitted in the visible range (Fig. 5A3). Since this process does not naturally occur in living systems, imaging rare earth materials through upconversion emission results in very low non-specific background for fluorescence and PDT, as is reviewed thoroughly by Moghe et al [94]. We will not go into details for this type of transducers because excellent and more exhaustive reviews have already been published on the subject [4, 93]. However, the large amount of in vitro and in vivo studies reporting an efficient UCNP induced PDT effect substantiate the promi.
Posted inUncategorized