Robert Nowakowski

Recent advances in modern medicine emphasize patient-centric and personalized therapeutic strategies, particularly for chronic and regenerative applications. Among emerging biomaterials, chitosan (CS) has gained considerable attention due to its biocompatibility, biodegradability, and antimicrobial properties, while its molecular weight strongly influences structural organization and interactions with active compounds. In this study, chitosan-based matrices—2% (w/v) low-molecular-weight CS, 4% (w/v) low-molecular-weight CS, and 2% (w/v) medium-molecular-weight CS—were developed and enriched with ibuprofen (IBU), a widely used non-steroidal anti-inflammatory drug, to improve topical delivery and reduce systemic side effects. The physicochemical properties of gelled thin films were investigated with emphasis on molecular arrangement, surface characteristics, and drug release behavior in phosphate-buffered saline. ATR-FTIR spectroscopy, contact angle measurements, and atomic force microscopy (AFM) were employed to evaluate structural and functional changes induced by IBU incorporation. Medium-molecular-weight CS exhibited lower water contact angles (≈69–73°) and higher surface free energy (≈41–44 mN m⁻¹) compared to low-molecular-weight CS, while IBU loading did not significantly alter wettability. AFM analysis revealed drug-induced surface roughness changes, with Ra increasing from 23.9 nm (2CS_M) to 29.4 nm after IBU loading and further to 35.5 nm following release. ATR-FTIR spectra confirmed preservation of characteristic chitosan amide I and II bands (∼1645 and ∼1556 cm⁻¹), with spectral changes in the 1450–1700 cm⁻¹ region indicating interactions between IBU and CS functional groups. Among the investigated systems, 2% (w/v) medium-molecular-weight chitosan demonstrated the most favorable sustained IBU release (∼50% after 48 h), highlighting its potential for dermal drug delivery and personalized therapeutic applications.

Two-dimensional (2D) supramolecular organization of asymmetric liquid crystal dimers containing two chemically different mesogenic groups, namely, cyanobiphenyl and pyreneiminomethyl phenoxy groups, linked with an oligomethylene linker of different length (six or eight -CH₂- units), was studied using scanning tunneling microscopy. For this purpose, monolayers of these dimers were deposited on an HOPG substrate from their solutions in hexane by drop-casting and imaged at nanometer resolution after drying. A detailed discussion of two possible different supramolecular organizations is presented. In the case of the first one, termed the "lamellar structure", the molecules in each layer are arranged in parallel molecular rows. Comparative analysis of the monolayer structure with already reported XRD data on 3D organization of the same molecules in a single crystal revealed significant differences resulting from (i) different ordering preferences in 2D and 3D systems and (ii) effects of the interactions of the deposited molecules with the graphite substrate. A small extension of the linker by two methylene groups does not change the type of ordering in the monolayer but causes an extension of the unit cell in one direction, indicating that the lamellar structure is stabilized by rows of densely packed large aromatic pyrene units. Studies of the derivative with a longer linker (containing eight -CH₂- units) also showed the possibility of the occurrence of an alternative type of its monolayer organization, termed here "aggregate structure". In this case, the monolayer consists of ordered aggregates of two molecules. According to the authors' knowledge, this type of structural organization has not yet been reported for this family of compounds. It is, however, qualitatively consistent with the already described supramolecular ordering in CBO5O.Py (CCDC 2019485), a compound closely resembling the dimers studied in this research.

The cross-linking temperature of polymers may affect the surface characteristics and molecular arrangement, which are responsible for their mechanical and physico-chemical properties. The aim of this research was to determine and explain in detail the mechanism of unit interlinkage of two-component chitosan/1,3-β-d-glucan matrices gelled at 90 °C. This required identifying functional groups interacting with each other and assessing surface topography providing material chemical composition. For this purpose, various spectroscopic and microscopic approaches, such as attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), were applied. The results indicate the involvement mainly of the C-C and C-H groups and C=O⋯HN moieties in the process of biomaterial polymerization. Strong chemical interactions and ionocovalent bonds between the N-glucosamine moieties of chitosan and 1,3-β-d-glucan units were demonstrated, which was also reflected in the uniform surface of the sample without segregation. These unique properties, hybrid character and proper cell response may imply the potential application of studied biomaterial as biocompatible scaffolds used in regenerative medicine, especially in bone restoration and/or wound healing.

This research discusses the CO₂ valorization via hydrogenation over the non-noble metal clusters of Ni and Cu supported on graphitic carbon nitride (g-C₃N₄). The Ni and Cu catalysts were characterized by conventional techniques including XRD, AFM, ATR, Raman imaging, and TPR and were tested via the hydrogenation of CO₂ at 1 bar. The transition-metal-based catalyst designed with atom-economy principles presents stable activity and good conversions for the studied processes. At 1 bar, the rise in operating temperature during CO₂ hydrogenation increases the CO₂ conversion and the selectivity for CO and decreases the selectivity for methanol on Cu/CN catalysts. For the Ni/CN catalyst, the selectivity to light hydrocarbons, such as CH₄, also increased with rising temperature. At 623 K, the conversion attained ca. 20%, with CH₄ being the primary product of the reaction (CH₄ yield >80%). Above 700 K, the Ni/CN activity increases, reaching almost equilibrium values, although the Ni loading in Ni/CN is lower by more than 90% compared to the reference NiREF catalyst. The presented data offer a better understanding of the effect of the transition metals' small metal cluster and their coordination and stabilization within g-C₃N₄, contributing to the rational hybrid catalyst design with a less-toxic impact on the environment and health. Bare g-C₃N₄ is shown as a good support candidate for atom-economy-designed catalysts for hydrogenation application. In addition, cytotoxicity to the keratinocyte human HaCaT cell line revealed that low concentrations of catalysts particles (to 6.25 μg mL^-1) did not cause degenerative changes.

New donor–acceptor conjugated alternating or random copolymers containing 1-methyl-2-phenylbenzimidazole and benzothiadiazole (P1), diketopyrrolopyrrole (P4), or both acceptors (P2) are reported. The specific feature of these copolymers is the presence of a permanent dipole-bearing moiety (1-methyl-2-phenyl imidazole (MPI)) fused with the 1,4-phenylene ring of the polymer main chain. For comparative reasons, polymers of the same main chain but deprived of the MPI group were prepared, namely, P5 with diketopyrrolopyrrole and P3 with both acceptors. The presence of the permanent dipole results in an increase of the optical band gap from 1.51 eV in P3 to 1.57 eV in P2 and from 1.49 eV in P5 to 1.55 eV in P4. It also has a measurable effect on the ionization potential (IP) and electrochemical band gap (E_g^CV), leading to their decrease from 5.00 and 1.83 eV in P3 to 4.92 and 1.79 eV in P2 as well as from 5.09 and 1.87 eV in P5 to 4.94 and 1.81 eV in P4. Moreover, the presence of permanent dipole lowers the exciton binding energy (E_b) from 0.32 eV in P3 to 0.22 eV in P2 and from 0.38 eV in P5 to 0.26 eV in P4. These dipole-induced changes in the polymer properties should be beneficial for photovoltaic applications. Bulk heterojunction solar cells fabricated from these polymers (with PC₇₁BM acceptor) show low series resistance (r_s), indicating good electrical transport properties. The measured power conversion efficiency (PCE) of 0.54% is limited by the unfavorable morphology of the active layer.

Within the Waste2Fuel project, innovative, high-performance, and cost-effective fuel production methods from municipal solid wastes (MSWs) are sought for application as energy carriers or direct drop-in fuels/chemicals in the near-future low-carbon power generation systems and internal combustion engines. Among the studied energy vectors, C₁-C₂ alcohols and ethers are mainly addressed. This study presents a potential bio-derived ethanol oxidative coupling in the gas phase in multicomponent systems derived from hydrotalcite-containing precursors. The reaction of alcohol coupling to ethers has great importance due to their uses in different fields. The samples have been synthesized by the co-precipitation method via layered double hydroxide (LDH) material synthesis, with a controlled pH, where the M(II)/M(III) ≈ 0.35. The chemical composition and topology of the sample surface play essential roles in catalyst activity and product distribution. The multiple redox couples Ni²⁺/Ni³⁺, Cr²⁺/Cr³⁺, Mn²⁺/Mn³⁺, and the oxygen-vacant sites were considered as the main active sites. The introduction of Cr (Cr³⁺/Cr⁴⁺) and Mn (Mn³⁺/Mn⁴⁺) into the crystal lattice could enhance the number of oxygen vacancies and affect the acid/base properties of derived mixed oxides, which are considered as crucial parameters for process selectivity towards bio-DEE and bio-butanol, preventing long CH chain formation and coke deposition at the same time.

Within the Waste2Fuel project, innovative, high-performance, and cost-effective fuel production methods are developed to target the “closed carbon cycle”. The catalysts supported on different metal oxides were characterized by XRD, XPS, Raman, UV-Vis, temperature-programmed techniques; then, they were tested in CO₂ hydrogenation at 1 bar. Moreover, the V₂O₅ promotion was studied for Ni/Al₂O₃ catalyst. The precisely designed hydrotalcite-derived catalyst and vanadia-promoted Ni-catalysts deliver exceptional conversions for the studied processes, presenting high durability and selectivity, outperforming the best-known catalysts. The equilibrium conversion was reached at temperatures around 623 K, with the primary product of reaction CH₄ (>97% CH₄ yield). Although the Ni loading in hydrotalcite-derived NiWP is lower by more than 40%, compared to reference NiR catalyst and available commercial samples, the activity increases for this sample, reaching almost equilibrium values (GHSV = 1.2 × 10⁴ h^–1, 1 atm, and 293 K).

Alzheimer’s disease (AD) is characterized by progressive neurodegeneration associated with amyloid β (Aβ) peptide aggregation. The aggregation of Aβ monomers (AβMs) leads to the formation of Aβ oligomers (AβOs), the neurotoxic Aβ form, capable of permeating the cell membrane. Here, we investigated the effect of a fluorene-based active drug candidate, named K162, on both Aβ aggregation and AβO toxicity toward the bilayer lipid membrane (BLM). Electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM), and molecular dynamics (MD) were employed to show that K162 inhibits AβOs-induced BLM permeation, thus preserving BLM integrity. In the presence of K162, only shallow defects on the BLM surface were formed. Apparently, K162 modifies Aβ aggregation by bypassing the formation of toxic AβOs, and only nontoxic AβMs, dimers (AβDs), and fibrils (AβFs) are produced. Unlike other Aβ toxicity inhibitors, K162 preserves neurologically beneficial AβMs. This unique K162 inhibition mechanism provides an alternative AD therapeutic strategy that could be explored in the future.