Unleashing the antibacterial and antibiofilm potential of silica-based nanomaterials functionalized with an organotin(IV) compound

Bacterial diseases caused by superbugs are expected to be the main cause of death worldwide within a decade as a consequence of the resistance they are acquiring to the antibiotics currently in use, therefore, the field of new antibacterial treatments is currently being thoroughly studied. The present work focuses on the synthesis, functionalization, characterization and antibacterial behaviour of different systems based on three different silica-based nanostructured materials (MSN, mesoporous silica nanoparticles, SBA-15 Santa Barbara amorphous-15 and FSP fibrous slica nanoparticles) which serve as scaffolds for the support of different platforms to target and treat bacterial diseases and biofilm formation. Thus, (3-carboxypropyl)triphenylphosphonium bromide (PPh3+) and a cytotoxic organotin(IV) fragment (Sn) have been incorporated in the silica-based materials to study their potential activity in different antibacterial applications. After a complete characterization of the synthesized systems, which confirmed the incorporation of both the targeting and the therapeutic fragments within the nanostructured materials, the antibacterial study of the materials demonstrated bactericidal capacity against Escherichia coli and perturbation of the bacteria metabolism via oxidative stress through an enhanced ROS (reactive oxygen species) production. In addition, biofilm inhibition and eradication tests of bacterial strains were carried out, showing that the activity of the materials in both biofilm inhibition and eradication is dependent on the concentration of the material. Furthemore, the material MSN-AP(1:1)-PPh3+-Sn containing the targeting triphenylphosphonium and a "SnPh3" fragment is capable of inhibiting and eradicating up to 50% of the formation of biofilms, which is outstanding for metallodrug-functionalized silica-based systems compared with other materials based on metal nanoparticles supported on silica. Finally, a hemolysis study was carried out with the nanostructured systems proving to be non-toxic, making them adequate for their subsequent use in preclinical trials through in vivo models.

Tetraalkylammonium salts (TAS) in solar energy applications - A review on in vitro and in vivo toxicity

Tetraalkylammonium salt (TAS) is an organic salt widely employed as a precursor, additive or electrolyte in solar cell applications, such as perovskite or dye-sensitized solar cells. Notably, Perovskite solar cells (PSCs) have garnered acclaim for their exceptional efficiency. However, PSCs have been associated with environmental and health concerns due to the presence of lead (Pb) content, the use of hazardous solvents, and the incorporation of TAS in their fabrication processes, which significantly contributes to environmental and human health toxicity. As a response, there is a growing trend towards transitioning to safer and biobased materials in PSC fabrication to address these concerns. However, the potential health hazards associated with TAS necessitate a thorough evaluation, considering the widespread use of this substance. Nevertheless, the overexploitation of TAS could potentially increase the disposal of TAS in the ecosystem, thus, posing a major health risk and severe pollution. Therefore, this review article presents a comprehensive discussion on the in vitro and in vivo toxicity assays of TAS as a potential material in solar energy applications, including cytotoxicity, genotoxicity, in vivo dermal, and systemic toxicity. In addition, this review emphasizes the toxicity of TAS compounds, particularly the linear tetraalkyl chain structures, and summarizes essential findings from past studies as a point of reference for the development of non-toxic and environmentally friendly TAS derivatives in future studies. The effects of the TAS alkyl chain length, polar head and hydrophobicity, cation and anion, and other properties are also included in this review.

Enzyme-instructed morphology transformation of mitochondria-targeting peptide for the selective eradication of osteosarcoma

The treatment of osteosarcoma involves an adjuvant therapy that combines surgery and chemotherapy. However, considering that children are the main victims of osteosarcoma, replacing such a harsh treatment with a soft but powerful method that ensures a complete cure while having no adverse effects is highly desirable. To achieve this aim, we have developed a supramolecular therapeutic strategy based on morphology-transformable mitochondria-targeting peptides for the eradication of osteosarcoma with enhanced selectivity and reduced side effects. A newly designed micelle-forming amphiphilic peptide, l-Mito-FFYp, consisting of a phosphate substrate for the biomarker enzyme of osteosarcoma alkaline phosphatase (ALP), disassembles in response to the ALP enzyme in the cell membrane to generate positively charged l-Mito-FFY molecules, which diffuse inside the targeted cell and self-assemble to form nanostructures specifically inside the mitochondria to induce cell apoptosis.

Spatiotemporal Self-Assembly of Peptide Amphiphiles by Carbonic Anhydrase IX-Targeting Induces Cancer-Lysosomal Membrane Disruption

To achieve spatiotemporal control, an enzyme-instructed self-assembly system is widely used, but this approach typically has a small effect on cellular fate. In this study, we show that the intralysosomal assembly by a carbonic anhydrase IX (CAIX)-targeting peptide amphiphile (Pep-AT) can control cellular fate with a low therapeutic dose by tuning the surface charge based on pH change. Pep-AT self-assembles into a fibrous aggregate with a negative surface charge in an extracellular environment near CAIX. During endocytosis, it changes into a nanofiber with a positive surface charge at the lysosome. Then, it can disrupt the lysosomal membrane and induce cellular apoptosis. This study demonstrates that a spatiotemporal assembly induced by a cancer enzyme and specific organelle can control the cellular fate of cancer.