Three-dimensional (3D) optical microscopy can be used to understand and improve the delivery of nanomedicine. However, this approach cannot be performed for analyzing liposomes in tissues because the processing step to make tissues transparent for imaging typically removes the lipids. Here, we developed a tag, termed REMNANT, that enables 3D imaging of organic materials in biological tissues. We demonstrated the utility of this tag for the 3D mapping of liposomes in intact tissues. We also showed that the tag is able to monitor the release of entrapped therapeutic agents. We found that liposomes release their cargo >100-fold faster in tissues in vivo than in conventional in vitro assays. This allowed us to design a liposomal formulation with enhanced ability to kill tumor associated macrophages. Our development opens up new opportunities for studying the chemical properties and pharmacodynamics of administered organic materials in an intact biological environment. This approach provides insight into the in vivo behavior of degradable materials, where the newly discovered information can guide the engineering of the next generation of imaging and therapeutic agents.

Inorganic nanoparticles are a fascinating class of materials which promise great potential in numerous fields, including optical (bio)sensing. Many different kinds of such nanoparticles have been widely used for fluorescent sensing and imaging due to the different merits of fluorescent nanoparticles compared to molecular fluorophores.Progress made in the rational design of nanomaterials also allowed the synthesis of hybrid phosphorescent nanoparticles, that finds growing applications in sensing due to the combination of the interesting size-and shape-dependent properties of nanomaterials with a phosphorescence-type emission.In this review, we intend to highlight some of progress made in this active research area and update the database of various phosphorescent nanoparticles-based sensors on the basis of different sensing targets of interest in environmental, industrial and biomedical areas.Following an introduction and a discussion of merits of the synergy between nanomaterials and phosphorescence detection as compared to molecular luminophores the article assesses the kinds and specific features of nanomaterials often used in phosphorescence sensing. Specific examples on the use of phosphorescence nanoparticles in chemical sensing and bioimaging are given next. A final section intends to provide an overview of the prospects of such type of nanomaterials in the design of future devices for analytical chemistry.

BackgroundDifferentiation between hemorrhagic and ischemic stroke is currently made by brain imaging or analyzing blood and cerebrospinal fluid (CSF) samples. After describing a new drainage route from brain to nasal mucosa, nasal exudate samples can be considered a new and promising source of biomarkers. Saliva can also be evaluated.MethodsWe determined iron in nasal exudate and saliva samples from patients of acute stroke during the first 48 h from onset. A simple, non-invasive sampling procedure was employed to obtain information from the brain. Samples were taken with a pre-weighed swab, solved in a 2% nitric acid solution and iron was measured by inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS).ResultsA significant difference in the dispersion of results of iron concentration for both stroke subtypes was observed in nasal exudate samples. The interquartile range was 0.608 nmol mg−1 of iron for hemorrhagic strokes and only 0.044 nmol mg−1 for ischemic strokes. In saliva samples, however, the values were 0.236 vs. 0.157 nmol mg−1. A cut-off limit of 0.102 nmol of iron per mg of nasal exudate provides a methodology with a 90% of sensitivity and a 90% of specificity. The value of the area under (AUC) the receiver operating characteristic curve (ROC) for nasal exudate samples is 0.960, considered as very good in which regards to its predictive value.ConclusionsNon-invasive samples of nasal secretion have allowed obtaining, for the first time, information from the brain. Determination of iron in nasal exudate by ICP-MS allowed differentiation between ischemic and hemorrhagic strokes.

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