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Fungal melanins represent a resource for important breakthroughs in industry and medicine, but the characterization of their composition, synthesis, and structure is not well understood. Raman spectroscopy is a powerful tool for the elucidation of molecular composition and structure. In this work, we characterize the Raman spectra of wild-type Aspergillus fumigatus and Cryptococcus neoformans and their melanin biosynthetic mutants and provide a rough “map” of the DHN (A. fumigatus) and DOPA (C. neoformans) melanin biosynthetic pathways. We compare this map to the Raman spectral data of Aspergillus nidulans wild-type and melanin biosynthetic mutants obtained from a previous study. We find that the fully polymerized A. nidulans melanin cannot be classified according to the DOPA pathway; nor can it be solely classified according to the DHN pathway, consistent with mutational analysis and chemical inhibition studies. Our approach points the way forward for an increased understanding of, and methodology for, investigating fungal melanins.
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Synthesis of Biomimetic Melanin-Like Multifunctional Nanoparticles for pH Responsive Magnetic Resonance Imaging and Photothermal Therapy
The design and development of multifunctional nanoparticles have attracted great interest in biomedical research. This study aims to prepare pH-responsive melanin-like nanoparticles for T1-weighted magnetic resonance imaging (MRI) and photothermal therapy. The new multifunctional nanoparticles (amino-Fe-PDANPs) are synthesized by copolymerization of dopamine and its derivative amino-N-[2-(diethylamino) ethyl]-3,4-dihydroxy-benzenepropanamide (N-Dopa) at room temperature. The size of nanoparticles can be controlled by NaOH concentration. The incorporation of N-Dopa is characterized by NMR and FT-IR. From transmission electron microscopy (TEM), the nanoparticles exhibit excellent dispersion stability in water and are spherical in shape. The MRI measurement has demonstrated that amino-Fe-PDANPs have a significant signal enhancement in responding to the acidic solution. Confirmed by the photothermal study, the nanoparticles exhibit a high photothermal conversion efficiency. The melanin-like multifunctional nanoparticles integrate both diagnosis and therapeutic functionalities, indicating the potential for theranostic application.
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- PAR ID:
- 10322478
- Date Published:
- Journal Name:
- Nanomaterials
- Volume:
- 11
- Issue:
- 8
- ISSN:
- 2079-4991
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/nano11082107
