Bisphosphonates (BPs) are compounds resembling the pyrophosphate structure. BPs bind the mineral component of bones. During the bone resorption by osteoclasts, nitrogen-containing BPs are released and internalized, causing an inhibition of the mevalonate pathway. As a consequence, osteoclasts are unable to execute their function. Alendronate (ALN) is a bisphosphonate used to treat osteoporosis. Its administration could be associated with adverse effects. The purpose of this study is to evaluate four different ALN concentrations, ranging from 10⁻⁶ to 10⁻¹⁰ M, in the presence of different combinations of M-CSF and RANKL, to find out the effect of low ALN concentrations on osteoclastogenesis using rat and human peripheral blood mononuclear cells. The cytotoxic effect of ALN was evaluated based on metabolic activity and DNA concentration measurement. The alteration in osteoclastogenesis was assessed by the activity of carbonic anhydrase II (CA II), tartrate-resistant acid phosphatase staining, and actin ring formation. The ALN concentration of 10⁻⁶ M was cytotoxic. Low ALN concentrations of 10⁻⁸ and 10⁻¹⁰ M promoted proliferation, osteoclast-like cell formation, and CA II activity. The results indicated the induction of osteoclastogenesis with low ALN concentrations. However, when high doses of ALN were administered, their cytotoxic effect was demonstrated.

Chronic wounds represent a significant socio-economic problem, and the improvement of their healing is therefore an essential issue. This paper describes the preparation and biological properties of a novel functionalized nanofiber wound dressing consisting of a polycaprolactone nanofiber carrier modified by a drug delivery system, based on the lipid particles formed by 1-tetradecanol and encapsulated gentamicin and tocopherol acetate. The cytotoxicity of extracts was tested using a metabolic activity assay, and the antibacterial properties of the extracts were tested in vitro on the bacterial strains Staphylococcus aureus and Pseudomonas aeruginosa. The effect of the wound dressing on chronic wound healing was subsequently tested using a mouse model. Fourteen days after surgery, the groups treated by the examined wound cover showed a lower granulation, reepithelization, and inflammation score compared to both the uninfected groups, a lower dermis organization compared to the control, a higher scar thickness compared to the other groups, and a higher thickness of hypodermis and bacteria score compared to both the uninfected groups. This work demonstrates the basic parameters of the safety (biocompatibility) and performance (effect on healing) of the dressing as a medical device and indicates the feasibility of the concept of its preparation in outpatient conditions using a suitable functionalization device.

Electrospinning has advanced from a lab technique to an industrial method, enabling modern filters that are high-performing, sustainable, recyclable, and non-toxic. This study produced recycled PA6 nanofibers using green solvents and incorporated non-toxic CuO nanoparticles via industrial free-surface electrospinning. Polymer solutions with concentrations of 12.5, 15.0 and 17.5 (w/v)% were electrospun directly onto recyclable polypropylene spunbond/meltblown nonwoven substrates to produce nanofibers with average fiber sizes of 80–250 nm. Electrospinning parameter optimization revealed that the 12.5 wt.% PA6 solution and the 2–3 mm·s⁻¹ winding speed had the optimal performance, attaining 98.06% filtering efficiency and a 142 Pa pressure drop. The addition of 5 wt.% CuO nanoparticles increased the membrane density and reduced the pressure drop to 162 Pa, thereby improving the filtration efficiency to 98.23%. Bacterial and viral filtration studies have demonstrated pathogen retention above 99%. Moreover, antibacterial and antiviral testing has demonstrated that membranes trap and inactivate microorganisms, resulting in a 2.0 log (≈approximately 99%) reduction in viral titer. This study shows that recycled PA6 can be converted into high-performance membranes using green, industrial electrospinning, introducing innovations such as non-toxic CuO functionalization and ultra-fine fibers on recyclable substrates, yielding sustainable filters with strong antimicrobial and filtration performance, which are suitable for personal protective equipment and medical filtration.

Co-cultures of osteoblasts and osteoclasts are on the rise because they enable a more complex study. Diseases such as osteoporosis are related to a higher age. Thus, cell isolation from adult individuals is necessary. Osteoblasts can be isolated from the rat femur by three methods: explant culture, explant culture with enzymatic pre-treatment, or enzymatic treatment. The isolation methods yield different populations of osteoblasts which, in a co-culture with peripheral blood mononuclear cells, might result in differences in osteoclastogenesis. Therefore, we examined the differences in osteogenic markers, cell proliferation, and the metabolic activity of isolated osteoblast-like cells in a growth and differentiation medium. We then evaluated the effect of the isolated populations of osteoblast-like cells on osteoclastogenesis in a subsequent co-culture by evaluating osteoclast markers, counting formed osteoclast-like cells, and analyzing their area and number of nuclei. Co-cultures were performed in the presence or absence of osteoclastogenic growth factors, M-CSF and RANKL. It was discovered that enzymatic isolation is not feasible in adult rats, but explant culture and explant culture with enzymatic pre-treatment were both successful. Explant culture with enzymatic pre-treatment yielded cells with a higher proliferation than explant culture in a growth medium. The differentiation medium reduced differences in proliferation during the culture. Some differences in metabolic activity and ALP activity were also found between the osteoblast-like cells isolated by explant culture or by explant culture with enzymatic pre-treatment, but only on some days of cultivation. According to microscopy, the presence of exogenous growth factors supporting osteoclastogenesis in co-cultures was necessary for the formation of osteoclast-like cells. In this case, the formation of a higher number of osteoclast-like cells with a larger area was observed in the co-culture with osteoblast-like cells isolated by explant culture compared to the explant culture with enzymatic pre-treatment. Apart from this observation, no differences in osteoclast markers were noted between the co-cultures with osteoblast-like cells isolated by explant culture and the explant culture with enzymatic pre-treatment. The TRAP and CA II activity was higher in the co-cultures with exogenous growth than that in the co-cultures without exogenous growth factors on day 7, but the opposite was true on day 14. To conclude, explant culture and explant culture with enzymatic pre-treatment are both suitable methods to yield osteoblast-like cells from adult rats capable of promoting osteoclastogenesis in a direct co-culture with peripheral blood mononuclear cells. Explant culture with enzymatic pre-treatment yielded cells with a higher proliferation. The explant culture yielded osteoblast-like cells which induced the formation of a higher number of osteoclast-like cells with a larger area compared to the explant culture with enzymatic pre-treatment when cultured with exogenous M-CSF and RANKL.

The global crisis concerning multidrug-resistant microorganisms necessitates the development of innovative antimicrobial strategies that avoid conventional antibiotics and overcome the toxicity and environmental persistence associated with traditional metal-based biocides. This work aims to develop safe and sustainable antibacterial filtration materials by integrating cationic hyperbranched polymer dendrimers (HBP) into electrospun nanofibers. Cationic HBPs were successfully embedded into recycled polyamide 6 nanofibers using industrial needleless electrospinning. Filtration efficiency, assessed against a 0.3 µm paraffin oil aerosol according to EN 149:2001, consistently exceeded 99.8%, meeting and surpassing the FFP3 classification threshold while maintaining low air resistance. The HBP-functionalized nanofibers exhibited pronounced contact-active antibacterial activity against Staphylococcus aureus and Escherichia coli. Quantitative plate count assays confirmed viability reductions of up to 74.1% after 2 h of co-incubation. Crucially, the absence of inhibition zones in agar diffusion tests confirmed that the active polymer was stably embedded within the nanofiber matrix and did not leach. Comprehensive toxicological tests, including cell line and 3D human skin and airway tissue models, confirmed the material’s safety for both dermal and respiratory contact. This study presents a scalable, metal-free, and environmentally responsible next-generation filtration system that combines high mechanical efficiency with active antimicrobial functionality.

In tissue engineering, the 3D constructs seeded with cells tested in vitro in static conditions suffer from poor cellular penetration and non-homogenous matrix deposition, due to the insufficient flow of nutrients, gases and signal molecules through the scaffold volume. However, a dynamic culture of cells can improve these drawbacks and simulate physiological conditions, such as flow in the canalicular system of bones. The purpose of this comparative study was to evaluate the different flow rates of 1 and 3 mL/min of perfusion bioreactor on human mesenchymal stromal cells (hMSCs), seeded in an osteogenic media on 3D porous constructs. After three weeks of dynamic cultivation, the metabolic activity and proliferation of the cells was evaluated, as well as the alkaline phosphatase (ALP) activity and the expression of bone related genes, RunX2, collagen type I and osteocalcin. The dynamic culture conditions did not influence the metabolic activity of hMSCs. The highest cell proliferation was detected on the scaffold cultured at a flow rate of 3 mL/min. The dynamic culture did not prove the penetration of cells into the scaffold's volume. The ALP activity, and PCR analysis of osteogenic markers RunX2 and collagen type I were highest on the scaffolds cultured at 1 mL/min, compared to the static culture and even to the dynamic culture at 3 mL/min. The study shows that hMSCs behave differently in different flow rates. While the higher flow rate (3 mL/min, shear stress 479 mPa) improved cell proliferation, the slower flow rate of 1 mL/min (shear stress 160 mPa) supported the ALP activity and expression of osteogenic marker genes. Interestingly, our expectation that dynamic culture improves cell penetration into the scaffold was not proved.