We demonstrate a new concept of carrier-free functionalized drug nanoparticles for targeted drug delivery. It exhibits significantly enhanced drug efficacy to folate receptor-positive cells with high selectivity and a high drug loading content up to more than 78%.

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A new strategy is presented for using doped small-molecule organic nanoparticles (NPs) to achieve high-performance fluorescent probes with strong brightness, large Stokes shifts and tunable emissions for in vitro and in vivo imaging. The host organic NPs are used not only as carriers to encapsulate different doped dyes, but also as fluorescence resonance energy transfer donors to couple with the doped dyes (as acceptors) to achieve multicolor luminescence with amplified emissions (AE). The resulting optimum green emitting NPs show high brightness with quantum yield (QY) of up to 45% and AE of 12 times; and the red emitting NPs show QY of 14% and AE of 10 times. These highly-luminescent doped NPs can be further surface modified with poly(maleic anhydride-alt-1-octadecene)-polyethylene glycol (C18PMH-PEG), endowing them with excellent water dispersibility and robust stability in various bio-environments covering wide pH values from 2 to 10. In this study, cytotoxicity studies and folic acid targeted cellular imaging of these multicolor probes are carried out to demonstrate their potential for in vitro imaging. On this basis, applications of the NP probes in in vivo and ex vivo imaging are also investigated. Intense fluorescent signals of the doped NPs are distinctly, selectively and spatially resolved in tumor sites with high sensitivity, due to the preferential accumulation of the NPs in tumor sites through the passive enhanced permeability and retention effect. The results clearly indicate that these doped NPs are promising fluorescent probes for biomedical applications.

We develop a new strategy of using surface functionalized small molecule organic dye nanoparticles (NPs) for targeted cell imaging. Organic dye (2-tert-butyl-9,10-di(naphthalen-2-yl)anthracene, TBADN) was fabricated into NPs and this was followed by surface modification with an amphipathic surfactant poly(maleic anhydride-alt-1-octadecene)-polyethylene glycol (C18PMH-PEG) through hydrophobic interactions to achieve good water dispersibility and bio-environmental stability. It should be noted that no additional inert materials were added as carriers, thus the dye-loading capacity of the resulting TBADN NPs is obviously higher than those of previously reported carrier-based structures. This would lead to much larger absorption and then much higher brightness. The resulting TBADN NPs possess comparable, if not higher, brightness than CdSe/ZnS quantum dots under the same conditions, with favorable biocompatibility. Significantly, TBADN NPs are readily conjugated with folic acid, and successfully applied in targeted cell imaging. These results show that water dispersible and highly stable organic NPs would be a promising new class of fluorescent probe for bioapplications in cellular imaging and labeling. This strategy may be straightforwardly extended to other organic dyes to achieve water dispersible NPs for cell imaging and drug delivery.

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Elevated ozone (O₃) generally affects microbial biomass and community structure in rhizosphere, but these effects are unclear in mycorrhizal plants because arbuscular mycorrhizal (AM) fungi often benefit microbial growth in the rhizosphere. Here, we investigate the effects of elevated O₃ on microbial biomass and community structure in the rhizosphere of mycorrhizal snap bean (Phaseolus vulgaris L.) with different O₃ sensitivity (R123: O₃-tolerant plant; S156: O₃-sensitive plant) based on the phospholipid fatty acids (PLFAs) method. Compared with ambient O₃, elevated O₃ significantly decreased mycorrhizal colonization rates in the 2 genotypes, especially in S156 plants. The wet masses of shoot and root were decreased by elevated O₃ in the 2 genotypes independent of AM inoculation, but they were higher in the mycorrhizal plant than in the nonmycorrhizal plant independent of O₃ concentration. Elevated O₃ significantly decreased the relative proportion of specific fungal PLFAs in the nonmycorrhizal plant, but this effect disappeared in the mycorrhizal plant. The relative proportions of specific PLFAs of other microbial groups (Gram-positive, Gram-negative, and actinomycete) in the rhizosphere and all specific PLFAs in the hyphosphere were not affected by elevated O₃ independent of AM inoculation. In the rhizosphere of the 2 genotypes, microbial community structure was changed by AM inoculation and elevated O₃ as well as by their interaction; in the hyphosphere, however, microbial community structure was changed by elevated O₃ only in R123 plants. It is concluded that AM inoculation can offset negative effect of elevated O₃ on fungal biomass but seems to enhance shift of microbial community structure in rhizosphere under elevated O₃.

Snap bean genotypes (Phaseolus vulgaris L.) with different ozone (O 3 ) sensitivities (line S156: O 3 -sensitive; line R123: O 3 -tolerant) were grown for 70 days with or without inoculation of arbuscular mycorrhizal (AM) fungi under ambient (C AMB = 20 nanolitres (nl)/l and elevated (C MID = '50 nl/l and C HIG = 80 nl/l) O 3 . Sequential determinations (leaf injury, pigment concentration, chlorophyll fluorescence, photosynthesis, etc) were carried out during plant growth to evaluate mycorrhizal influence on the photosynthetic function of the two genotypes under elevated O 3 . Inoculation with AM fungi alleviated leaf injury in both genotypes and delayed time of injury manifestation (TIM) in the R123 line at the blooming stage (growth stage (GS): 61-65 (Zadoks scale, Zadoks et al. 1974), 30-35 days after the onset of O 3 fumigation), but mycorrhizal effect was slight at the initial growth stage (GS 11-13, 0-5 days after onset of O 3 fumigation). Relative to the non-mycorrhizal plant, AM fungi inoculation increased the concentrations of chlorophyll (Chl) a, Chl b and carotenoids in S156 plants, regardless of O 3 levels, while in R123 plants a similar effect was observed only in the C AMB treatment. At the blooming (GS 61-65) and the pod filling (GS 71-77, 45-50 days after starting O 3 fumigation) stages, photosynthetic rate, stomatal conductance and transpiration rate for the two genotypes decreased with elevated O 3 in all treatments, although the effect was reduced in C AMB and C MID treatments in AM-inoculated plants; however, the mycorrhizal effect was slight in the C HIG treatment. Intercellular carbon dioxide concentration increased with elevated O 3 regardless of AM fungi inoculation, but it was lower in the mycorrhizal plants than in the non-mycorrhizal plants, in most cases. Furthermore, AM fungi inoculation significantly increased the maximum quantum yield of photosystem II (PS II) photochemistry (Fv/Fm) and electron transport rate in both genotypes in the C HIG treatment. The present study indicated that in some cases, AM fungi inoculation can enhance plant tolerance to elevated O 3 through improving plant photosynthetic function, but the effect was reduced by serious O 3 stress.

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