Luiza Madalina Gradinaru

This study examines the forensic classification and identification of counterfeit banknotes through an integrated analysis of empirical observations obtained during field and laboratory investigations. Particular attention is given to the procedural workflow of forensic examination and to the complementary use of macroscopic, microscopic, optical, and physicochemical methods. Preliminary field assessments were conducted using document examination loupes and other optical magnification devices, while laboratory investigations employed advanced analytical systems and specialized software to characterize the substrate, printing inks, graphic elements, and security features. The findings demonstrate that reliable counterfeit banknote identification cannot be based solely on visual inspection. A multidisciplinary approach integrating morphological, optical, and compositional evidence is essential for distinguishing sophisticated counterfeits from genuine banknotes and for formulating scientifically robust forensic conclusions. This study also highlights the need for continuously updated examination procedures in response to the increasing technological sophistication of banknote counterfeiting.

Thermosensitive polyurethane (PU) hydrogels were prepared and loaded with meloxicam (MX), a nonsteroidal anti-inflammatory drug (NSAID). The role of different excipients, i.e., eucalyptus essential oil as well as poly(vinylpyrrolidone), poly(ethylene glycol) and their mixture, was highlighted. The sol–gel transition induced by temperature increase was evidenced by rheological measurements in oscillatory shear conditions. The viscoelastic behavior was investigated at 37 °C in various shear conditions, evidencing the network strength and stability of formulations. The structural recovery was monitored after applying high strain values, and the self-healing ability was revealed. Depending on the excipient, the gel samples loaded with MX release between 60% and 90% of the active substance. It was shown that the Fickian and chain relaxation contributions compete during MX release from PU-based hydrogels. In vitro anti-inflammatory activity was evaluated and discussed.

The paper reports viscosity data for aqueous solutions of hydroxypropyl cellulose (HPC) in the presence of poly(N-vinylpyrrolidone) (PVP) in dilute, semidilute and concentrated regimes. The two polymers are miscible over the entire range of composition. In dilute solution, mixed isolated coils with more extended chain conformation are formed and binary polymer-polymer interactions are favored when a small amount of PVP is added to HPC solutions. The viscosity increases in semidilute and concentrated regimes due to chain entanglements and a pronounced synergistic effect was observed upon the addition of a small amount of PVP to the HPC isotropic solution. The intermolecular hydrogen bonding between the hydroxyl groups of HPC and the carbonyl groups of PVP influences the overall flow behavior.

Nowadays, utilizing biodegradable and bio-inspired substances and combining them in innovative ways is a prerequisite for obtaining new and useful materials. In this paper, we designed and characterized eco-friendly materials as alternatives for packaging and medical applications. Thus, cellulose fibers of medical gauze or filter paper were coated with a mixed solution containing poly(vinyl alcohol) (PVA), plant-based synthesized silver particles (AgPs), and magnetite (MG). The composites and their components were studied using UV-Vis, FTIR, and Energy-Dispersive X-ray (EDX) spectroscopy, Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM) to evidence the presence, size, surface charge, morphology, and chemical composition of particles in the composites, as well as particle interactions. Their proven hydrophobic and antibacterial character could recommend them for the design of antifouling medical coatings and food packaging.

Meloxicam is a promising non-steroidal anti-inflammatory drug (NSAID) for acute and chronic pain prevention and treatment. Due to its poor water solubility, the clinical use of meloxicam is limited. In addition, for transdermal applications, the impermeability of the skin makes it difficult to conceive an appropriate NSAID-based delivery system that can penetrate through the skin barrier. Hydrophilic/hydrophobic gels, designed as transdermal drug delivery systems, can considerably improve other drug administration types (such as oral or intravenous), avoiding or limiting the side effects. The main purpose of this paper is to present some physicochemical and pharmaceutical considerations about meloxicam and to review the most important research concerning the gels used for the transdermal delivery of meloxicam. Thus, smart polymeric networks, semi-solid systems (lipogels, emulgels), β-cyclodextrin-based gels, liposomes (ethosomes, niosomes, flexosomes, transferosomes, menthosomes, invasomes), and nanostructured lipid carriers, with analgesic and anti-inflammatory activity, are discussed. The key objective of this study was to highlight various gel formulations with enhanced properties, which could be used in a minimally invasive manner for the sustained administration of meloxicam.

The fluorenyl methyl oxycarbonyl phenylalanyl-phenylalanine methyl ester (Fmoc-Phe-Phe-Ome) was synthetized using the liquid phase synthesis strategy. This derivative was separated by hydrophobic interaction chromatography, its purity was analyzed by RP-HPLC and it was characterized by mass spectrometry. This extremely hydrophobic peptide conjugate was incorporated into aqueous solutions of Pluronic^® F127 at low temperatures (below 10 °C). The temperature induced sol–gel transition was investigated by rheological measurements. A delay of the sol–gel transition, caused by the presence of low concentrations of Fmoc-Phe-Phe-Ome (up to 1%), enables better control of the gelation process. The viscoelastic properties of hybrid networks were investigated at 37 °C in different shear conditions. The Pluronic/peptide systems reported herein provide promising alternatives for developing innovative injectable gels as suitable platforms in cancer treatment.

Meloxicam (MX) is a nonsteroidal anti-inflammatory drug (NSAID) used mainly to reduce pain, inflammation, and fever. In the present study, thermosensitive polyurethane (PU)-based hydrogels with various excipients (PEG, PVP, HPC, and essential oil) were prepared and loaded with MX. Rheological investigations were carried out on the PU-based formulations in various shear regimes, and their viscoelastic characteristics were determined. The average size of the PU micelles was 35.8 nm at 37 °C and slightly increased at 37 nm in the presence of MX. The zeta potential values of the hydrogels were between −10 mV and −11.5 mV. At pH = 6 and temperature of 37 °C, the formulated PU-based hydrogels loaded with MX could deliver significant amounts of the active substance, between 60% and 80% over 24–48 h and more than 90% within 2 weeks. It was found that anomalous transport phenomena dominated MX’s release mechanism from the PU-based networks. The results are encouraging for further studies aiming to design alternative carriers to commercial dosage forms of nonsteroidal anti-inflammatory drugs.

Thermoresponsive Pluronic® F127 (PL) gels in water were investigated through rheological tests in different shear conditions. The gel strength was tuned with the addition of 1% polysaccharide solution. In the presence of xanthan gum (XG), the viscoelastic behavior of PL-based hydrogels was improved in aqueous environment, but the rheological behavior was less changed with the addition of XG in PBS solutions, whereas in the presence of 0.1 M NaCl, the viscoelastic parameters decreased. PL micellar networks exhibited a self-healing ability, recovering their initial structure after applying cycles of high strain. The rheological characteristics of the PL hydrogel changed with the addition of 1% polysaccharides (xanthan gum, alginate, κ-carrageenan, gellan, or chitosan). PL/polysaccharide systems form temperature-responsive hydrogels with shear thinning behavior, yield stress, and self-healing ability, being considered a versatile platform for injectable biomaterials or bioinks. Thus, in the presence of xanthan gum in aqueous medium, the gel strength was improved after applying a high strain (the values of elastic modulus increased). The other investigated natural polymers induced specific self-healing behaviors. Good performances were observed with the addition of gellan gum, alginate, and κ-carrageenan, but for high values of strain, the ability to recover the initial structure decreased. A modest self-healing behavior was observed in the presence of chitosan and xanthan gum dissolved in NaCl solution.

Hydrogels are a favorable alternative to accelerate the burn wound healing process and skin regeneration owing to their capability of absorbing contaminated exudates. The bacterial infections that occur in burn wounds might be treated using different topically applied materials, but bacterial resistance to antibiotics has become a major problem worldwide. Therefore, the use of non-antibiotic treatments represents a major interest in current research. In this study, new antibiocomposite hydrogels with anti-inflammatory and antimicrobial properties based on hyaluronic acid (HA) and sodium alginate (AG) were obtained using 4-(4,6-dimethoxy-1,3,5-triazinyl-2)-4-methylmorpholinium chloride as an activator. The combination of Ibuprofen, a non-steroidal anti-inflammatory drug commonly used to reduce inflammation, fever and pain in the body, with zinc oxide nanoparticles (ZnO NPs) was used in this study aimed at creating a complex hydrogel with anti-inflammatory and antimicrobial action and capable of improving the healing process of wounds caused by burns. FTIR spectra confirmed the cross-linking of AG with HA as well as the successful incorporation of ZnO NPs. Using electronic microscopy, it was noticed that the morphology of hydrogels is influenced by the incorporation of ZnO nanoparticles. Moreover, the incorporation of ZnO nanoparticles into hydrogels also has an influence on the swelling behavior at both pH 7.4 and 5.4. In fact, the swelling rate is lower when the amounts of the activator, HA and ZnO NPs are high. A drug release rate of almost 100% was observed for hydrogels without ZnO NPs, whereas the addition of nanoparticles to hydrogels led to a decrease in the release rate to 68% during 24 h. Cellular viability tests demonstrated the non-cytotoxic behavior of the hydrogels without the ZnO NPs, whereas a weak to moderate cytotoxic effect was noticed for hydrogels with ZnO NPs. The hydrogels containing 4% and 5% ZnO NPs, respectively, showed good antimicrobial activity against the S. aureus strain. These preliminary data prove that these types of hydrogels can be of interest as biomaterials for the treatment of burn wounds.

Hydrogels are 3D networks with an excellent ability to retain a high amount of water or biological fluids, representing suitable candidates for wound dressing applications. They can provide a protective barrier and a moist environment, facilitating wound treatment. The present paper focuses on physical hydrogels obtained from poly(vinyl alcohol) (PVA) and pullulan (PULL) mixtures in different weight ratios by using the freezing/thawing method. Hybrid hydrogels of similar polymer compositions were prepared in the presence of 0.5% Laponite^® RD. The influence of polysaccharide and clay addition on the properties of PVA hydrogels was investigated. Scanning electron microscopy showed evidence of the inner porous structure. The viscoelastic properties were investigated in different shear conditions and revealed the influence of the hydrogel composition on the network strength. The swelling behavior was followed in physiological saline solutions at 37 °C and pH = 7.4. For all samples, a quasi-Fickian diffusion mechanism was found. The delivery of neomycin sulfate was studied in similar conditions as for the swelling tests (0.15 M NaCl solutions; 37 °C; pH = 7.4) and different kinetic models were used to determine the release mechanism. The Peppas–Sahlin approach described very well the in vitro drug release mechanism from the polymeric hydrogels in the absence of clay. However, the hybrid polymer/clay hydrogels showed the best fit with the Korsmeyer–Peppas model. According to the present study, the porous membranes containing 40–60% PULL (in absence of clay) are suitable for the release of therapeutic agents at wound sites in physiological conditions.