Water-Soluble Non-Ionic PEGylated Porphyrins: A Versatile Category of Dyes for Basic Science and Applications

Porphyrin-Based Organic Nanoparticles with NIR-IIa Fluorescence for Orthotopic Glioblastoma Theranostics

The development of efficient theranostic nanoagents for the precise diagnosis and targeted therapy of glioblastoma (GBM) remains a big challenge. Herein, we designed and developed porphyrin-based organic nanoparticles (PNP NPs) with strong emission in the near-infrared IIa window (NIR-IIa) for orthotopic GBM theranostics. PNP NPs possess favorable photoacoustic and photothermal properties, high photostability, and low toxicity. After modification with the RGD peptide, the obtained PNPD NPs exhibited enhanced blood-brain barrier (BBB) penetration capability and GBM targeting ability. NIR-IIa imaging was employed to monitor the in vivo biodistribution and accumulation of the nanoparticles, revealing a significant enhancement in penetration depth and signal-to-noise ratio. Both in vitro and in vivo results demonstrated that PNPD NPs effectively inhibited the proliferation of tumor cells and induced negligible side effects in normal brain tissues. In general, the work presented a kind of brain-targeted porphyrin-based NPs with NIR-IIa fluorescence for orthotopic glioblastoma theranostics, showing promising prospects for clinical translation.

Water-Soluble Star Polymer as a Potential Photoactivated Nanotool for Lysozyme Degradation

The development of nanotools for chemical sensing and macromolecular modifications is a new challenge in the biomedical field, with emphasis on artificial peptidases designed to cleave peptide bonds at specific sites. In this landscape, metal porphyrins are attractive due to their ability to form stable complexes with amino acids and to generate reactive oxygen species when irradiated by light of appropriate wavelengths. The issues of hydrophobic behavior and aggregation in aqueous environments of porphyrins can be solved by using its PEGylated derivatives. This work proposes the design of an artificial photo-protease agent based on a PEGylated mercury porphyrin, able to form a stable complex with l-Tryptophan, an amino acid present also in the lysozyme structure (a well-known protein model). The sensing and photodegradation features of PEGylated mercury porphyrin were exploited to detect and degrade both l-Trp and lysozyme using ROS, generated under green (532 nm) and red (650 nm) light lasers. The obtained system (Star3600_Hg) and its behavior as a photo-protease agent were studied by means of several spectroscopies (UV-Vis, fluorescence and circular dichroism), and MALDI-TOF mass spectrometry, showing the cleavage of lysozyme and the appearance of several short-chain residues. The approach of this study paves the way for potential applications in theranostics and targeted bio-medical therapies.

A Multifunctional Conjugated Polymer Developed as an Efficient System for Differentiation of SH-SY5Y Tumour Cells

Polymer-based systems have been demonstrated in novel therapeutic and diagnostic (theranostic) treatments for cancer and other diseases. Polymers provide a useful scaffold to develop multifunctional nanosystems that combine various beneficial properties such as drug delivery, bioavailability, and photosensitivity. For example, to provide passive tumour targeting of small drug molecules, polymers have been used to modify and functionalise the surface of water-insoluble drugs. This approach also allows the reduction of adverse side effects, such as retinoids. However, multifunctional polymer conjugates containing several moieties with distinct features have not been investigated in depth. This report describes the development of a one-pot approach to produce a novel multifunctional polymer conjugate. As a proof of concept, we synthesised polyvinyl alcohol (PVA) covalently conjugated with rhodamine B (a tracking agent), folic acid (a targeting agent), and all-trans retinoic acid (ATRA, a drug). The obtained polymer (PVA@RhodFR) was characterised by MALDI-TOF mass spectrometry, gel permeation chromatography, thermal analysis, dynamic light-scattering, NMR, UV-Vis, and fluorescence spectroscopy. Finally, to evaluate the efficiency of the multifunctional polymer conjugate, cellular differentiation treatments were performed on the neuroblastoma SH-SY5Y cell line. In comparison with standard ATRA-based conditions used to promote cell differentiation, the results revealed the high capability of the new PVA@RhodFR to induce neuroblastoma cells differentiation, even with a short incubation time and low ATRA concentration.

Photosensitized Thermoplastic Nano-Photocatalysts Active in the Visible Light Range for Potential Applications Inside Extraterrestrial Facilities

Among different depollution methods, photocatalysis activated by solar light is promising for terrestrial outdoor applications. However, its use in underground structures and/or microgravity environments (e.g., extraterrestrial structures) is forbidden. In these cases, there are issues related to the energy emitted from the indoor lighting system because it is not high enough to promote the photocatalytic mechanism. Moreover, microgravity does not allow the recovery of the photocatalytic slurry from the depolluted solution. In this work, the synthesis of a filmable nanocomposite based on semiconductor nanoparticles supported by photosensitized copolyacrylates was performed through a bulk in situ radical copolymerization involving a photosensitizer macromonomer. The macromonomer and the nanocomposites were characterized through UV-Vis, fluorescence and NMR spectroscopies, gel permeation chromatography and thermogravimetric analysis. The photocatalytic activity of the sensitized nanocomposites was studied through photodegradation tests of common dyes and recalcitrant xenobiotic pollutants, employing UV-Vis and visible range (λ > 390 nm) light radiations. The sensitized nanocomposite photocatalytic performances increased about two times that of the unsensitized nanocomposite and that of visible range light radiation alone (>390 nm). The experimental data have shown that these new systems, applied as thin films, have the potential for use in indoor deep underground and extraterrestrial structures.