Search Results (23)

Cyanoacrylates, known for their rapid polymerization and strong bonding capabilities, are widely used in industrial and medical applications. This study investigates the impacts of different process atmospheres with varying water and oxygen contents—air, argon, and argon/silane—on the curing and adhesion mechanisms of cyanoacrylate adhesives on oxidized copper substrates. Raman spectroscopy indicated that the curing process in argon and argon/silane atmospheres was slower compared to ambient air, likely due to the reduced moisture content of the atmosphere. However, the degree of curing and the inter- and intramolecular interactions within the adhesive volume showed no significant differences across atmospheres. X-ray photoelectron spectroscopy (XPS) and infrared reflection absorption spectroscopy (IRRAS) revealed that strong ionic interactions between cyanoacrylate and the copper surface oxide were absent in the low-moisture argon atmosphere. The introduction of silane resulted in the formation of silicon oxides and other silane-derived compounds, which probably contributed to the formation of these ionic interactions, similar to those observed in air. This study highlights the critical influence of the surrounding atmosphere on the adhesive properties of cyanoacrylates, with implications for optimizing bonding processes in various environments. Full article

Background: Heracleum sphondylium, a medicinal plant used in Romanian ethnopharmacology, has been proven to have remarkable biological activity. The escalating concerns surrounding antimicrobial resistance led to a special attention being paid to new efficient antimicrobial agents based on medicinal plants and nanotechnology. We report the preparation of a novel, simple phytocarrier that harnesses the bioactive properties of H. sphondylium and silver nanoparticles (HS-Ag system). Methods: H. sphondylium’s low metabolic profile was determined through gas chromatography–mass spectrometry and electrospray ionization–quadrupole time-of-flight–mass spectrometry. The morphostructural properties of the innovative phytocarrier were analyzed by X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, dynamic light scattering, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The antioxidant activity was evaluated using total phenolic content, ferric reducing antioxidant power, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) in vitro assays. The antimicrobial activity screening against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, and Escherichia coli was conducted using the agar well diffusion method. The 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay estimated the in vitro potential cytotoxicity on normal human dermal fibroblasts (NHDF) and cervical cancer (HeLa) cells. Results: A total of 88 biomolecules were detected, such as terpenoids, flavonoids, phenolic acids, coumarins, phenylpropanoids, iridoids, amino acids, phytosterols, fatty acids. The HS-Ag phytocarrier heightened efficacy in suppressing the growth of all tested bacterial strains compared to H. sphondylium and exhibited a significant inhibition of HeLa cell viability. Conclusions: The new HS-Ag phytocarrier system holds promise for a wide range of medical applications. The data confirm the capacity to augment the pertinent theoretical understanding in the innovative field of antimicrobial agents. Full article

Bacterial infections and their increasing resistance to antibiotics pose a significant challenge in medical treatment. This study presents the synthesis and characterization of novel carbon dots (CDs) using levofloxacin (Lf), curcumin (Cur), and tea polyphenols (TP) through a facile hydrothermal method. The synthesized curcumin-tea polyphenol@carbon dots (Cur-TP@CDs) and levofloxacin-tea polyphenol@carbon dots (Lf-TP@CDs) were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy, confirming their unique structural and chemical properties. Cur-TP@CDs exhibited an average particle size of 1.32 nanometers (nm), while Lf-TP@CDs averaged 1.58 nm. Both types demonstrated significant antibacterial activity, with Lf-TP@CDs showing superior effectiveness against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in broth dilution and disc diffusion assays. Biofilm inhibition assays revealed a significant reduction in biofilm formation at higher concentrations. The ultraviolet-visible (UV-vis) and photoluminescence (PL) spectral analyses indicated efficient photon emission, and electron paramagnetic resonance (EPR) analysis showed increased singlet oxygen generation, enhancing bactericidal effects. Live and dead bacterial staining followed by scanning electron microscopy (SEM) analysis confirmed dose-dependent bacterial cell damage and morphological deformities. These findings suggest that Cur-TP@CDs and Lf-TP@CDs are promising antibacterial agents, potentially offering a novel approach to combat antibiotic-resistant bacterial infections. Full article

This study showed that a polylactide (PLA)-based composite filled with nanostructured hydroxyapatite (HAp) and a natural extract from the rhizome of Curcuma longa L. could provide an alternative to commonly used fossil-based plasticsfor food packaging. The incorporation of HAp into the PLA matrix had a positive effect on improving selected properties of the composites; the beneficial effect could be enhanced by introducing a green modifier in the form of an extract. Prior to the fabrication of the composite, the filler was characterized in terms of morphology and composition, and the composite was then fully characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman and Fourier transform infrared spectroscopy (FT-IR), and the mechanical, thermal, thermomechanical, and optical properties were investigated. The proposed material exhibits antioxidant properties against DPPH radicals and antibacterial performance against Escherichia coli (E. coli). The results showed that the nanocomposite has the highest antioxidant and antibacterial properties for 10 wt% HAp with an average diameter of rod-shaped structures below 100 nm. In addition, the introduction of turmeric extract had a positive effect on the tensile strength of the nanocomposites containing 1 and 5% HAp. As the resulting material adsorbs light in a specific wavelength range, it can be used in the medical sector, food-packaging, or coatings. Full article

Polymeric Intraocular lenses (IOLs) are vital for restoring vision following cataract surgery and for correcting refractive errors. Despite technological and medical advancements, challenges persist in achieving optimal vision and preventing complications. Surface modifications aim to mitigate the risk of posterior capsule opacification (PCO), while pre-operative measurements aid in selecting suitable IOLs. However, individualized solutions are lacking and there is a clear demand for the development of fully customized IOL surfaces. We employ laser micromachining technology for precise modifications via ablation on PMMA and acrylic IOLs, using femtosecond (fs), nanosecond (ns), and diode continuous wave (CW) lasers, at wavelengths ranging from near-ultraviolet to infrared. Characterization reveals controlled ablation patterning, achieving feature sizes from as small as 400 nm to several micrometers. Regular and confocal micro-Raman spectroscopy revealed alterations of the IOL materials’ structural integrity for some patterning cases, thus affecting the optical properties, while these can be minimized by the proper selection of micromachining conditions. The results suggest the feasibility of accurate IOL patterning, which could offer personalized vision correction solutions, based on relevant corneal wavefront data, thus surpassing standard lenses, marking a significant advancement in cataract surgery outcomes. Full article

Phenolic compounds (PheCs) are particularly relevant in many different frameworks due to their pro-oxidant and antioxidant activities. In fact, on the one hand, they are considered very dangerous pro-oxidant agents that can be present in the environment as pollutants in wastewater and soil from different industrial and agricultural industries. On the other hand, the antioxidant influence of PheCs available in natural products (including foods) is nowadays considered essential for preserving human health. Conventional techniques for detecting PheCs present some disadvantages, such as requiring expensive instrumentation and expert users and not allowing in situ measurements. This is the reason why there is a high interest in the development of simple, sensitive, specific, and accurate sensing methods for PheCs. Enzymes are often used for this purpose, and laccases with unique optical properties are adopted as bio-elements for sensing schemes. The present paper aims to revise the optical properties of laccases and their use for developing PheC detection and quantification methods used in different fields such as environment monitoring, food characterization and medical applications. In particular, the results offered by UV, visible and infrared absorption, fluorescence, Raman, and surface-enhanced Raman spectroscopy (SERS) have been considered. The enzymatic biosensing devices developed using the related optical signals have been reported, and a comparison of their performances has carried out. A brief description of the main characteristics of laccase and phenols is also given. Full article

Accurately printing customizable scaffolds is a challenging task because of the complexity of bone tissue composition, organization, and mechanical behavior. Graphene oxide (GO) and poly-L-lactic acid (PLLA) have drawn attention in the field of bone regeneration. However, as far as we know, the Fischer–Koch model of the GO/PLLA association for three-dimensional (3D) printing was not previously reported. This study characterizes the properties of GO/PLLA-printed scaffolds in order to achieve reproducibility of the trabecula, from virtual planning to the printed piece, as well as its response to a cell viability assay. Fourier-transform infrared and Raman spectroscopy were performed to evaluate the physicochemical properties of the nanocomposites. Cellular adhesion, proliferation, and growth on the nanocomposites were evaluated using scanning electron microscopy. Cell viability tests revealed no significant differences among different trabeculae and cell types, indicating that these nanocomposites were not cytotoxic. The Fischer Koch modeling yielded satisfactory results and can thus be used in studies directed at diverse medical applications, including bone tissue engineering and implants. Full article

The sudden outbreak of the COVID-19 pandemic led to a huge concern globally because of the astounding increase in mortality rates worldwide. The medical imaging computed tomography technique, whole-genome sequencing, and electron microscopy are the methods generally used for the screening and identification of the SARS-CoV-2 virus. The main aim of this review is to emphasize the capabilities of various optical techniques to facilitate not only the timely and effective diagnosis of the virus but also to apply its potential toward therapy in the field of virology. This review paper categorizes the potential optical biosensors into the three main categories, spectroscopic-, nanomaterial-, and interferometry-based approaches, used for detecting various types of viruses, including SARS-CoV-2. Various classifications of spectroscopic techniques such as Raman spectroscopy, near-infrared spectroscopy, and fluorescence spectroscopy are discussed in the first part. The second aspect highlights advances related to nanomaterial-based optical biosensors, while the third part describes various optical interferometric biosensors used for the detection of viruses. The tremendous progress made by lab-on-a-chip technology in conjunction with smartphones for improving the point-of-care and portability features of the optical biosensors is also discussed. Finally, the review discusses the emergence of artificial intelligence and its applications in the field of bio-photonics and medical imaging for the diagnosis of COVID-19. The review concludes by providing insights into the future perspectives of optical techniques in the effective diagnosis of viruses. Full article

Silver nanoparticles (Ag-NPs) are most effective against pathogens and have widely been studied as antibacterial agents in commodity clothing, medical textile, and other hygiene products. However, prolonged utilization of silver and rapid mutation in bacterium stains has made them resistant to conventional silver agents. On the other hand, strict compliance against excessive utilization of toxic reagents and the current sustainability drive is forcing material synthesis toward green routes with extended functionality. In this study, we proposed an unprecedented chemical-free green synthesis of bioactive Ag-NPs without the incorporation of any chemicals. Cinnamon essential oil (ECO) was used as a bio-reducing agent with and without the mediation of lime extract. A rapid reaction completion with better shape and size control was observed in the vicinity of lime extract when incorporated into the reaction medium. The interaction of natural metabolites and citrus compounds with nanoparticles was established using Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The application of as-prepared nanoparticles on textiles encompasses extended bioactivity to treated fabric with infused easy-care performance. To the best of our knowledge, this is the first reported instance of utilizing bioactive silver nanoparticles as a functional finish, both as an antimicrobial and as for easy care in the absolute absence of toxic chemicals. The easy-care performance of fabric treated with lime-mediated nanoparticles was found to be 141^O, which is around 26% better than bare cotton without any significant loss in fabric strength. Furthermore, to enlighten the sustainability of the process, the development traits were mapped with the United Nations Sustainable Development Goals (SDGs), which show significant influence on SDGs 3, 8, 9, and 14. With the effective suspension of microorganisms, added functionality, and eco-mapping with SDGs with the chemical-free synthesis of nanoparticles, widespread utilization can be found in various healthcare and hygiene products along with the fulfillment of sustainability needs. Full article

^99mTc-based radiopharmaceuticals are the most commonly used medical radioactive tracers in nuclear medicine for diagnostic imaging. Due to the expected global shortage of ⁹⁹Mo, the parent radionuclide from which ^99mTc is produced, new production methods should be developed. The SORGENTINA-RF (SRF) project aims at developing a prototypical medium-intensity D-T 14-MeV fusion neutron source specifically designed for production of medical radioisotopes with a focus on ⁹⁹Mo. The scope of this work was to develop an efficient, cost-effective and green procedure for dissolution of solid molybdenum in hydrogen peroxide solutions compatible for ^99mTc production via the SRF neutron source. The dissolution process was extensively studied for two different target geometries: pellets and powder. The first showed better characteristics and properties for the dissolution procedure, and up to 100 g of pellets were successfully dissolved in 250–280 min. The dissolution mechanism on the pellets was investigated by means of scanning electron microscopy and energy-dispersive X-ray spectroscopy. After the procedure, sodium molybdate crystals were characterized via X-ray diffraction, Raman and infrared spectroscopy and the high purity of the compound was established by means of inductively coupled plasma mass spectroscopy. The study confirmed the feasibility of the procedure for production of ^99mTc in SRF as it is very cost-effective, with minimal consumption of peroxide and controlled low temperature. Full article

Polysaccharides are one of the most abundant natural polymers and their molecular structure influences many crucial characteristics—inter alia hydrophobicity, mechanical, and physicochemical properties. Vibrational spectroscopic techniques, such as infrared (IR) and Raman spectroscopies are excellent tools to study their arrangement during polymerization and cross-linking processes. This review paper summarizes the application of the above-mentioned analytical methods to track the structure of natural polysaccharides, such as cellulose, hemicellulose, glucan, starch, chitosan, dextran, and their derivatives, which affects their industrial and medical use. Full article

The continuous real-time monitoring of human health using biomedical sensing devices has recently become a promising approach to the realization of distant health monitoring. In this paper, the piezoelectric characteristics of the silk fibroin (SF) natural polymer were analyzed as the material used for obtaining sensing information in the application of distance health monitoring. To enhance the SF piezoelectricity, this paper presents the development of a novel SF-based sensor realized by combining SF with different carbon nanofiber (CNF) densities, and for such newly developed SF-based sensors comprehensive performance analyses have been performed. Versatile methods including the scanning electron microscope, Fourier transform infrared spectroscopy, Raman and X-ray diffraction measurements and impedance analysis were used to study the morphologic, mechanical and electrical properties of the developed SF-based sensor. The SF with CNF samples was analyzed for three different pressure loads (40 N, 60 N and 80 N) in 500 compression test cycles. The analyses thoroughly describe how combining natural polymer SF with different CNF densities impacts the piezoelectricity and mechanical strength of the proposed SF-based sensor. The developed piezoelectric SF-based sensors were further tested on humans in real medical applications to detect generated piezoelectric voltage in versatile body movements. The maximum piezoelectricity equal to 2.95 ± 0.03 V was achieved for the jumping movement, and the SF sample with a CNF density equal to 0.4% was tested. Obtained results also show that the proposed SF-based sensor has an appropriate piezoelectric sensitivity for each of the analyzed body movement types, and that the proposed SF-based sensor can be applied in real medical applications as a biomedical sensing device. The proposed SF-based sensor’s practical implementation is further confirmed by the results of cytotoxicity analyses, which show that the developed sensor has a non-toxic and biocompatible nature and can be efficiently used in skin contact for biomedical wearable health monitoring applications. Full article

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. Full article

The role of the oral microbiome and its effect on dental diseases is gaining interest. Therefore, it has been sought to decrease the bacterial load to fight oral cavity diseases. In this study, composite materials based on chitosan, chitosan crosslinked with glutaraldehyde, chitosan with zinc oxide particles, and chitosan with copper nanoparticles were prepared in the form of thin films, to evaluate a new alternative with a more significant impact on the oral cavity bacteria. The chemical structures and physical properties of the films were characterized using by Fourier transform infrared spectroscopy (FTIR,) Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), elemental analysis (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and contact angle measurements. Subsequently, the antimicrobial activity of each material was evaluated by agar diffusion tests. No differences were found in the hydrophilicity of the films with the incorporation of ZnO or copper particles. Antimicrobial activity was found against S. aureus in the chitosan film crosslinked with glutaraldehyde, but not in the other compositions. In contrast antimicrobial activity against S. typhimurium was found in all films. Based on the data of present investigation, chitosan composite films could be an option for the control of microorganisms with potential applications in various fields, such as medical and food industry. Full article

Poly(L-lactic acid) (PLLA) is a biocompatible, biodegradable, and semi-crystalline polymer with numerous applications including food packaging, medical implants, stents, tissue engineering scaffolds, etc. Hydroxyapatite (HA) is the major component of natural bone. Conceptually, combining PLLA and HA could produce a bioceramic suitable for implants and bone repair. However, this nanocomposite suffers from poor mechanical behavior under tensile strain. In this study, films of PLLA and HA were prepared with small amounts of nontoxic WS₂ nanotubes (INT-WS₂). The structural aspects of the films were investigated via electron microscopy, X-ray diffraction, Raman microscopy, and infrared absorption spectroscopy. The mechanical properties were evaluated via tensile measurements, micro-hardness tests, and nanoindentation. The thermal properties were investigated via differential scanning calorimetry. The composite films exhibited improved mechanical and thermal properties compared to the films prepared from the PLLA and HA alone, which is advantageous for medical applications. Full article