Fabrication data of two light-responsive systems to release an antileishmanial drug activated by infrared photothermal heating

Tuning structures and properties of self-healing silsesquioxane films using block copolymers

Designing siloxane-based materials with self-healing properties is crucial for various applications. In this study, we report the preparation of organosiloxane-based thin films with a crack-healing capability, using 1,2-bis(triethoxysilyl)ethane ((EtO)3Si-C2H4-Si(OEt)3) and poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)-type amphiphilic block copolymers. A lamellar mesostructure with alternating polymer and silsesquioxane layers (O1.5Si-C2H4-SiO1.5), featuring a periodicity of 9.56 nm, was formed through evaporation-induced self-assembly. The film exhibited reversible swelling behavior in response to changes in humidity. The cracks on the film disappeared immediately under humid conditions (90% relative humidity at room temperature). The nanoindentation hardness and elastic modulus of the film were higher than those of conventional lamellar silsesquioxane thin films prepared using a quaternary ammonium-type surfactant, which was attributable to the formation of thicker siloxane layers. Improved solvent resistance of the film was also confirmed by the fact that the mesostructure and crack-healing abilities were maintained even after immersion in ethanol. Thus the use of polymeric surfactants enhanced the mechanical properties and chemical stability of the mesostructured composites. These findings will lead to the development of self-healing siloxane-based coatings for various applications.

Peroxidase (POD) Mimicking Activity of Different Types of Poly(ethyleneimine)-Mediated Prussian Blue Nanoparticles

Prussian blue nanoparticles (PBNPs) have been identified as a promising candidate for biomimetic peroxidase (POD)-like activity, specifically due to the metal centres (Fe3+/Fe2+) of Prussian blue (PB), which have the potential to function as catalytically active centres. The decoration of PBNPs with desired functional polymers (such as amino- or carboxylate-based) primarily facilitates the subsequent linkage of biomolecules to the nanoparticles for their use in biosensor applications. Thus, the elucidation of the catalytic POD mimicry of these systems is of significant scientific interest but has not been investigated in depth yet. In this report, we studied a series of poly(ethyleneimine) (PEI)-mediated PBNPs (PB/PEI NPs) prepared using various synthesis protocols. The resulting range of particles with varying size (~19-92 nm) and shape combinations were characterised in order to gain insights into their physicochemical properties. The POD-like nanozyme activity of these nanoparticles was then investigated by utilising a 3,3',5,5'-tetramethylbenzidine (TMB)/H2O2 system, with the catalytic performance of the natural enzyme horseradish peroxidase (HRP) serving as a point of comparison. It was shown that most PB/PEI NPs displayed higher catalytic activity than the PBNPs, with higher activity observed in particles of smaller size, higher Fe content, and higher Fe2+/Fe3+ ratio. Furthermore, the nanoparticles demonstrated enhanced chemical stability in the presence of acid, sodium azide, or high concentrations of H2O2 when compared to HRP, confirming the viability of PB/PEI NPs as a promising nanozymatic material. This study disseminates fundamental knowledge on PB/PEI NPs and their POD-like activities, which will facilitate the selection of an appropriate particle type for future biosensor applications.

Souza AB, Levita DP, Mello CC, da Silva AFM, dos Santos TC, Ronconi CM. Innovating Leishmaniasis Treatment: A Critical Chemist's Review of Inorganic Nanomaterials

Leishmaniasis, a critical Neglected Tropical Disease caused by Leishmania protozoa, represents a significant global health risk, particularly in resource-limited regions. Conventional treatments are effective but suffer from serious limitations, such as toxicity, prolonged treatment courses, and rising drug resistance. Herein, we highlight the potential of inorganic nanomaterials as an innovative approach to enhance Leishmaniasis therapy, aligning with the One Health concept by considering these treatments' environmental, veterinary, and public health impacts. By leveraging the adjustable properties of these nanomaterials─including size, shape, and surface charge, tailored treatments for various diseases can be developed that are less harmful to the environment and nontarget species. We review recent advances in metal-, oxide-, and carbon-based nanomaterials for combating Leishmaniasis, examining their mechanisms of action and their dual use as standalone treatments or drug delivery systems. Our analysis highlights a promising yet underexplored frontier in employing these materials for more holistic and effective disease management.

Antimicrobial and Cytotoxic Effect of Positively Charged Nanosilver-Coated Silk Sutures

Sutures are a crucial component of surgical procedures, serving to close and stabilize wound margins to promote healing. However, microbial contamination of sutures can increase the risk of surgical site infections (SSI) due to colonization by pathogens. This study aimed to tackle SSI by synthesizing positively charged silver nanoparticles (P-AgNPs) and using them to produce antimicrobial sutures. The P-AgNPs were reduced and stabilized using polyethylenimine (PEI), a cationic branched polymer. The physiochemical characteristics of P-AgNPs were confirmed from the surface plasmon resonance (SPR) peak at 419 nm, spherical morphology with a particle size range of 8-10 nm, PEI functional groups on NPs, a hydrodynamic diameter of 12.3 ± 2.4 nm, and a zeta potential of 31.3 ± 6 mV. Subsequently, the surfaces of silk sutures were impregnated with P-AgNPs at different time intervals (24, 48, and 96 h) using an ex situ method. Scanning electron microscopy (SEM) and tensile strength studies were conducted to determine the coating and durability of the NP-coated sutures. The NPs were quantified on sutures using inductively coupled plasma optical emission spectrophotometry (ICP-OES), which was in the range of 1-5 μg. Primarily, antimicrobial activity was studied using three microorganisms (Candida albicans, Streptococcus mutans, and Staphylococcus aureus) for both P-AgNPs and suture-coated P-AgNPs using the agar diffusion method. The results showed that only the NPs and NP-coated sutures exhibited enhanced antimicrobial effects against bacteria and fungi. Finally, the cytotoxicity of the sutures was investigated using stem cells from the apical papilla (SCAPs) for 24 h, which exhibited more than 75% cell viability. Overall, the results indicate that NP-coated sutures can potentially be used as antimicrobial sutures to diminish or inhibit SSI in postoperative or general surgery patients.