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One important limitation of topical photodynamic therapy (PDT) is the limited tissue penetration of precursors. Microneedles (MNs) are minimally invasive devices used to promote intradermal drug delivery. Dissolving MNs contain drug-associated to polymer blends, dissolving after insertion into skin, allowing drug release. This study comprises development and characterization of a pyramidal model of dissolving MNs (500 μm) prepared with 5% wt/wt aminolevulinic acid and 20% wt/wt Gantrez AN-139 in aqueous blend. Protoporphyrin IX formation and distribution were evaluated in tumor mice model by using fluorescence widefield imaging, spectroscopy, and confocal microscopy. MNs demonstrated excellent mechanical resistance penetrating about 250 μm with minor size alteration in vitro, and fluorescence intensity was 5-times higher at 0.5 mm on average compared to cream in vivo (being 10 ± 5 a.u. for MNs and 2.4 ± 0.8 a.u. for cream). Dissolving MNs have overcome topical cream application, being extremely promising especially for thicker skin lesions treatment using PDT.

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Photodynamic procedures have been used in many applications, ranging from cancer treatment to microorganism inactivation. Photodynamic reactions start with the activation of a photosensitizing molecule with light, leading to the production of cytotoxic molecules that promote cell death. However, establishing the correct light and photosensitizer dosimetry for a broadband light source remains challenging. In this study, we proposed a theoretical mathematical model for the photodegradation of protoporphyrin IX (PpIX), when irradiated by multi‐wavelength light sources. The theoretical model predicts the experimental photobleaching (temporal change in PpIX concentration) of PpIX for different light sources. We showed that photobleaching occurs independently of the light source wavelengths but instead depends only on the number of absorbed photons. The model presented here can be used as an important mathematical approach to better understand current photodynamic therapy protocols and help achieve optimization of the doses delivered.

Resumo A implementação de atividades práticas que envolvam cores constitui uma estratégia poderosa para estimular o interesse de crianças e adolescentes para a Ciência. Devido ao seu forte apelo visual e presença no cotidiano, as cores despertam a curiosidade dos estudantes e propiciam o aprendizado de conceitos fundamentais no campo da óptica, tais como reflexão, transmissão e refração. Nesse trabalho, descrevemos um programa de atividades desenvolvido para ensinar conceitos de óptica presentes na formação de cores a partir de materiais simples, baratos e acessíveis. Através de demonstrações abertas e discussões autônomas por parte dos estudantes, elucidamos o processo de formação de cores por reflexão e transmissão, bem como a razão pela qual se pode visualizar objetos incolores. As atividades aqui descritas foram apresentadas num evento de divulgação científica direcionado a crianças e adolescentes com idade entre 8 e 17 anos.

The speckle pattern observed in multimode fiber, is closely related to the modal noise. In this paper we study the intensity distribution of the speckle patterns over the output surface of a multimode graded index fiber as a function of the incident beam alignement over the input surface of the fiber. Three kinds of incident beam misalignment speckle patterns were registrated photographically. Our results shown that the aforementioned distribution is highly dependent on the incident beam alignement.

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