In recent years, new cross-linkers from renewable resources have been sought to replace toxic synthetic compounds of this type. One of the most popular synthetic cross-linking agents used for biomedical applications is glutaraldehyde. However, the unreacted cross-linker can be released from the materials and cause cytotoxic effects. In the present work, dialdehyde starch nanocrystals (NDASs) were obtained from this polysaccharide nanocrystal form as an alternative to commonly used cross-linking agents. Then, 5–15% NDASs were used for chemical cross-linking of native chitosan (CS), gelatin (Gel), and a mixture of these two biopolymers (CS-Gel) via Schiff base reaction. The obtained materials, forming thin films, were characterized by ATR-FTIR, SEM, and XRD analysis. Thermal and mechanical properties were determined by TGA analysis and tensile testing. Moreover, all cross-linked biopolymers were also characterized by hydrophilic character, swelling ability, and protein absorption. The toxicity of obtained materials was tested using the Microtox test. Dialdehyde starch nanocrystals appear as a beneficial plant-derived cross-linking agent that allows obtaining cross-linked biopolymer materials with properties desirable for biomedical applications.

In this work, a composite material based on titanium(IV) oxide and iron(II,III) oxide was prepared using mechanothermal method. The obtained composite system was thoroughly characterized using techniques such as scanning electron microscopy, X-ray powder diffraction, thermogravimetric analysis, and nanoparticle tracking analysis. The acute toxicity of the composite material was evaluated with Microtox. In addition, the material’s photocatalytic potential was studied in photodegradation tests of ibuprofen. The composite system revealed magnetic properties of potential usage in its recovery after photocatalytic tests. However, the photocatalytic activity of TiO₂–Fe₃O₄ was lower than that of bare TiO₂. In the photocatalytic tests performed under UV (365 nm) light, a 44% reduction of initial ibuprofen concentration in the sample was noted for bare TiO₂, while for TiO₂–Fe₃O₄ composite, only a 19% reduction was observed. In visible light (525 nm), both materials achieved statistically insignificant photodegradation rates, which was contrary to the anticipated effect for TiO₂–Fe₃O₄. The observation was explained by a side oxidation reaction of Fe₃O₄ to Fe₂O₃ by the generated reactive oxygen species (ROS) in the photocatalytic process, which significantly diminished the amount of available ROS for ibuprofen degradation. The oxidation process appearing within TiO₂–Fe₃O₄ was evident and easily observed as the color of the material turned from gray to brown. Acute toxicity assay performed with the use of Microtox revealed reduced toxicity of TiO₂–Fe₃O₄ (32% inhibition of the Aliivibrio fischeri bacteria cell viability according to bioluminescence emitted) when compared to bare Fe₃O₄ (56% inhibition), whereas bare TiO₂ was non-toxic. In the study, the processes occurring during the photocatalytic reaction were analyzed and discussed in the context of the available literature data.

Wound healing and skin tissue regeneration remain the most critical challenges faced by medical professionals. Titanium(IV) oxide-based materials were proposed as components of pharmaceutical formulations for the treatment of difficult-to-heal wounds and unsightly scarring. A gallic acid-functionalized TiO₂ nanomaterial (TiO₂-GA) was obtained using the self-assembly technique and characterized using the following methods: scanning electron microscopy (SEM), transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), X-ray powder diffraction (XRPD), infrared spectroscopy (IR), Raman spectroscopy and thermogravimetry (TG). Additionally, physicochemical and biological tests (DPPH assay, Microtox^® acute toxicity test, MTT assay) were performed to assess antioxidant properties as well as to determine the cytotoxicity of the novel material against eukaryotic (MRC-5 pd19 fibroblasts) and prokaryotic (Staphylococcus aureus, Escherichia coli, Candida albicans, Aliivibrio fischeri) cells. To determine the photocytotoxicity of the material, specific tests were carried out with and without exposure to visible light lamps (425 nm). Following the results, the TiO₂-GA material could be considered an additive to dressings and rinsing suspensions for the treatment of difficult-to-heal wounds that are at risk of bacterial infections.

Magnesium(II) sulfanyl porphyrazine with peripheral morpholinethoxy substituents was embedded on the surface of titanium(IV) dioxide nanoparticles. The obtained nanocomposites were characterized with the use of particle size and distribution (NTA analysis), electron microscopy (SEM), thermal analysis (TGA), FTIR–ATR spectroscopy, and X-ray powder diffraction (XRD). The measured particle size of the obtained material was 327.4 ± 15.5 nm. Analysis with XRD showed no visible changes in the crystallinity of the material after deposition of porphyrazine on the TiO₂ surface. However, SEM images revealed noticeable changes in the morphology of the obtained hybrid material: higher aggregation and less ordered structure of the aggregates. The TGA analysis revealed the lost 3.6% (0.4 mg) of the mass of obtained material in the range 250–550 °C. In the FTIR–ATR analysis, C-H stretching vibratins in the range of 3000–2800 cm⁻¹, originating from porphyrazine moieties, were detected. The photocatalytic applicability of the nanomaterial was assessed in photodegradation studies of methylene blue and bisphenol A as reference environmental pollutants. In addition, the photocatalytic degradation of carbamazepine with porphyrazine/TiO₂ hybrids as photocatalysts was studied, accompanied by an HPLC chromatography assessment of photodegradation. In total, 43% of the initial concentration was achieved in the case of bisphenol A, after 4 h of irradiation, whereas 57% was achieved in the case of carbamazepine. In each photodegradation reaction, the activity of the obtained photocatalytic nanomaterial was proved with almost linear degradation. The photodegradation reaction rate constants were calculated, and revealed 5.75 × 10⁻⁵ s⁻¹ for bisphenol A and 5.66 × 10⁻⁵ s⁻¹ for carbamazepine.

Glycoproteins play essential roles in numerous biological processes, yet their controlled interaction with synthetic materials remains challenging due to structural complexity and heterogeneity of glycan moieties. In this study, starch-based magnetic nanomaterials functionalized with phenylboronic acid were developed and evaluated for pH-dependent interactions with α-1-acid glycoprotein (AGP). Dialdehyde starch (DAS) and carboxymethyl starch (CMS) were functionalized with phenylboronic acid to obtain DAS-PBA and CMS-PBA, which were subsequently used as coatings for magnetite nanoparticles, yielding the corresponding magnetic nanocomposites. The polymers and nanocomposites were comprehensively characterized using spectroscopic, microscopic, and thermal techniques. The functional accessibility of boronic acid groups was assessed using an Alizarin Red S assay. Binding studies demonstrated pH-dependent interactions with AGP, with enhanced binding observed under alkaline conditions, consistent with the behavior of boronic acid–diol interactions. Among the investigated systems, CMS-PBA-based materials exhibited higher AGP binding capacities compared to DAS-PBA-based analogues. Furthermore, partial release of AGP from the magnetic nanocomposites was achieved under mildly acidic conditions, confirming the reversible nature of the interactions.