Search Results (402)

Sustainable deepwater drilling for oil and gas offers significant potential. In this work, we synthesized a nanoscale collapse-prevention agent by grafting didecyldimethylammonium chloride onto spherical nano-silica and characterized it using Fourier-transform infrared spectroscopy, thermogravimetric analysis, zeta-potential, and particle-size measurements, as well as SEM and TEM. Adding 1 wt% of this agent to a bentonite slurry only marginally alters its rheology and maintains acceptable low-temperature flow properties. Microporous-membrane tests show filtrate passing through 200 nm pores drops to 55 mL, demonstrating excellent plugging. Core-immersion studies reveal that shale cores retain integrity with minimal spalling after prolonged exposure. Rolling recovery assays increase shale-cutting recovery to 68%. Wettability tests indicate the water contact angle rises from 17.1° to 90.1°, and capillary rise height falls by roughly 50%, reversing suction to repulsion. Together, these findings support a synergistic plugging–adsorption–hydrophobization mechanism that significantly enhances wellbore stability without compromising low-temperature rheology. This work may guide the design of high-performance collapse-prevention additives for safe, efficient deepwater drilling. Full article

Fuel cells, as one of the most promising alternatives to lithium-ion batteries for portable power systems, still face significant challenges. A critical issue is their substantial performance degradation under low-humidity conditions. To address this, researchers commonly add silica to components. This study employs a control variable method to systematically investigate the impact of four parameters—gas stoichiometry, temperature, humidity, and silica content—on fuel cell performance. Initially, the effects of gas stoichiometry, temperature, and humidity on performance were examined. Subsequently, hydrophilic silica was incorporated into the membrane electrode assembly (MEA) to assess its potential for improving performance in low-humidity environments. Experimental results reveal that under 100% humidification, silica addition had a minimal impact on performance, particularly at high temperatures where performance improved by only 2.5%. This is attributed to increased water production at elevated temperatures, which—when combined with silica’s water retention properties—exacerbates flooding. However, when humidity was reduced to 50%, silica incorporation significantly enhanced performance. At high temperatures, silica addition resulted in a 126.2% performance improvement, demonstrating its efficacy as a rational strategy under low-humidity conditions. Full article

Nafion, while a benchmark proton exchange membrane (PEM) for fuel cells, suffers from significant performance degradation at elevated temperatures and low humidity due to dehydration and diminished mechanical stability. To address these limitations, this study investigated the development and characterization of Nafion nanocomposite membranes incorporating sulfonated silica layered materials (sSLMs). The inherent lamellar structure, high surface area, and abundant sulfonic acid functionalities of sSLMs were leveraged to synergistically enhance membrane properties. Our results demonstrate that sSLM incorporation significantly improved ion exchange capacity, water uptake, and dimensional stability, leading to superior water retention and self-diffusion at higher temperatures. Critically, the nanocomposite membranes exhibited remarkably enhanced proton conductivity, particularly under demanding conditions of 120 C and low relative humidity (i.e., 20% RH), where filler-free Nafion largely ceases to conduct. Single H₂/O₂ fuel cell tests confirmed these enhancements, with the optimal sSLM-Nafion nanocomposite membrane (N-sSLM₅) achieving a two-fold power density improvement over pristine Nafion at 120 C and 20% RH (340 mW cm⁻² vs. 117 mW cm⁻² for Nafion). These findings underscore the immense potential of sSLM as a functional filler for fabricating robust and high-performance PEMs, paving the way for the next generation of fuel cells capable of operating efficiently under more challenging environmental conditions. Full article

Excessive carbon dioxide (CO₂) emissions represent a critical challenge in mitigating global warming, necessitating advanced separation technologies for efficient carbon capture. Silica-based membranes have attracted significant attention due to their exceptional chemical, thermal, and mechanical stability under harsh operating conditions. In this study, we introduce a novel layered hybrid membrane designed based on amine-functionalized silica precursors, where a distinct affinity gradient is engineered by incorporating two types of amine-functionalized materials. The top layer was composed of high-affinity amine species to maximize CO₂ sorption, while a sublayer with milder affinity facilitated smooth CO₂ diffusion, thereby establishing a continuous solubility gradient across the membrane. A dual approach, combining comprehensive experimental testing and rigorous theoretical modeling, was employed to elucidate the underlying CO₂ transport mechanisms. Our results reveal that the hierarchical structure significantly enhances the intrinsic driving force for CO₂ permeation, leading to superior separation performance compared to conventional homogeneous facilitated transport membranes. This study not only provides critical insights into the design principles of affinity gradient membranes but also demonstrates their potential for scalable, high-performance CO₂ separation in industrial applications. Full article

Thread-based analytical devices are low-cost, portable, and easy to use, making them ideal for detecting various biomolecules like glucose and DNA with minimal sample requirements, while also offering environmental benefits through their biodegradability. This study explores the potential of zwitterionic poly(sulfobetaine methacrylate) brushes modified cotton thread (PSBMA@threads) as an innovative substitute for DNA solid-phase extraction. The PSBMA polymer brushes were synthesized on cotton threads via surface-initiated atom transfer radical polymerization (SI-ATRP). The usability of the PSBMA@threads for DNA extraction from cell lysates containing cell debris, proteins, and detergents was evaluated. Characterization using SEM, FTIR, and EDS confirmed the successful functionalization with PSBMA polymer brushes. The antifouling properties of PSBMA@threads, including resistance to non-specific protein adsorption and underwater oil repellency, were assessed. The results demonstrated selective DNA capture from protein and lipid-rich lysates. Optimized extraction parameters improved DNA yield, enabling efficient extraction from tumor cells, which successfully underwent PCR amplification. Comparative experiments with commercial silica membrane-based columns revealed that PSBMA@threads exhibited comparable DNA extraction capability. The PSBMA@threads maintained extraction capability after six months of ambient storage, highlighting its stability and cost-effectiveness for nucleic acid isolation in analytical applications. Full article

Proton exchange membrane (PEM) is a key component of PEM fuel cells, where the membrane plays a decisive role in determining system efficiency and overall performance. The modification of PEMs with hydrophilic dopants represents a promising strategy for extending the operational range of these devices, particularly in low-humidity and high-temperature regimes. In this study, Nafion membranes were modified with silica nanoparticles via the sol–gel method; samples with 1, 3, 5, and 10 wt.% of SiO₂ were obtained. Evaluation of key parameters demonstrated improvement of water uptake and proton conductivity for modified membranes with silica content up to 5 wt.%, while no significant changes in thermal stability (30–700 °C) were observed. The structural changes in the composite membranes were investigated using the small-angle X-ray scattering (SAXS) technique. SAXS data were analyzed using a model-dependent approach: the spherical ionic domain model was modified to account for the scattering contribution from silica nanoparticles. The results obtained demonstrated a reduction in the size of unmodified ionic domains, indicating reorganization of the composite membrane’s microstructure. Full article

Background/Objectives: Guided bone regeneration (GBR) is a regenerative technique used to treat maxillary osseous defects to enable implant placement for prosthetic rehabilitation. It is generally performed with the use of barrier membranes and bone substitute materials of human or animal origin. Here, we report the clinical and histological outcomes of a horizontal GBR, treated using only synthetic biomaterials. Methods: A graft of nanocrystalline hydroxyapatite (NH) embedded in a silica gel matrix was used to fill a horizontal bone defect. The graft was covered with a titanium-reinforced dense polytetrafluoroethylene (TR-dPTFE) membrane, and primary closure was completed and maintained for 10 months. Then, the site was re-opened for membrane removal and implant insertion. During implant bed preparation, a bone biopsy was obtained for histological evaluation. A metal–ceramic crown was fitted, and the 5-year follow-up after prosthetic loading showed clinical and radiographically healthy tissues. Results: Histological examination revealed good integration of the biomaterial into the surrounding tissues, which were composed of lamellar bone trabeculae and connective tissue. New bone formation occurred not only around the NH granules but even inside the porous amorphous particles. Conclusions: The combination of NH and the TR-dPTFE membrane produced good clinical and histological results, which remained stable for 5 years. Full article

(1) Background: The chorioallantoic membrane (CAM) model has the potential to contribute to the development of personalized medicine based on individual cancer patients. We previously established the CAM model using patient-derived CIC-DUX4 sarcoma cells. We also used the CAM model for characterization and a comparison with the mouse model by examining the tumor accumulation of small-size, highly dispersive mesoporous silica nanoparticles (MSNs). (2) Method: In this study, we transplanted a variety of cancer cell lines, including patient-derived osteosarcoma (OS) and extraskeletal osteosarcoma (ESOS) cells. Patient-derived OS, ESOS and other cell lines were transplanted onto CAMs. The proliferation of cancer cells within CAM tumors was confirmed using H&E staining. For the comparison of the CAM and mouse models, rhodamine B-labeled MSNs were administered intravenously to CAMs and to xenograft mice. Tumor accumulation was evaluated by examining fluorescence and by confocal microscopy. The biodistribution of MSNs was examined by measuring the Si content by ICP. (3) Results: H&E staining demonstrated the proliferation of cancer cells of OS, ESOS and others on CAMs. While growth patterns and morphologies varied among different cancer types, H&E staining confirmed the establishment of tumors. As for the tumor accumulation, both the CAM and mouse models showed that MSNs were selectively accumulated in the tumors in both the CAM and mouse models. (4) Conclusions: We have expanded the range of CAM models by using a variety of cancer cells, including patient-derived cell lines. We also report that the small-size, highly dispersive MSNs exhibit excellent tumor accumulation in both the CAM and mouse models. These results point to the usefulness of the CAM model for patient-derived cancer cells as well as for evaluating drug carriers for tumor targeting. Full article

Background/Objectives: Nanocarrier particle design for treating chronic pulmonary diseases presents several challenges, including anatomical and physiological barriers. Drug-repurposing technology using monodispersed spherical silica is one of the innovative ways to deliver drugs. In the present study, the anticancer potential of combinational cisplatin/ribavirin was explored for targeted lung cancer therapeutics. Methods: Monodispersed spherical silica (80 nm) capable of diffusing into the tracheal mucus region was chosen and doped with 10 wt% superparamagnetic iron oxide nanoparticles (SPIONs). Subsequently, it was wrapped with chitosan (Chi, 0.6 wt/vol%), functionalized with 5% wt/wt cisplatin (Cp)/ribavarin (Rib) and angiotensin-converting enzyme 2 (ACE-2) (1.0 μL/mL). Formulations are based on monodispersed spherical silica or halloysite and are termed as (S/MSSiO₂/Chi/Cp/Rib) or (S/Hal/Chi/Cp/Rib), respectively. Results: X-ray diffraction (XRD) and diffuse reflectance UV-visible spectroscopy (DRS-UV-vis) analysis of S/MSSiO₂/Chi/Cp/Rib confirmed the presence of SPION nanoclusters on the silica surface (45% coverage). The wrapping of chitosan on the silica was confirmed with a Fourier transformed infrared (FTIR) stretching band at 670 cm⁻¹ and ascribed to the amide group of the polymer. The surface charge by zetasizer and saturation magnetization by vibrating sample magnetometer (VSM) were found to be −15.3 mV and 8.4 emu/g. The dialysis membrane technique was used to study the Cp and Rib release between the tumor microenvironment and normal pH ranges from 5.5 to 7.4. S/MSSiO₂/Chi formulation demonstrated pH-responsive Cp and Rib at acidic pH (5.6) and normal pH (7.4). Cp and Rib showed release of ~27% and ~17% at pH 5.6, which decreases to ~14% and ~3.2% at pH 7.4, respectively. To assess the compatibility and cytotoxic effect of our nanocomposites, the cell viability assay (MTT) was conducted on cancer lung cells A549 and normal HEK293 cells. Conclusions: The study shows that the designed nanoformulations with multifunctional capabilities are able to diffuse into the lung cells bound with dual drugs and the ACE-2 receptor. Full article

Lithium orthosilicate (Li₄SiO₄) has demonstrated a high CO₂ adsorption rate and capacity and its suitability to be implemented in industry as CO₂ capture technology at high temperatures. The optimum solid adsorbent should present a porous structure to maximize surface and enable a high sorption rate. In this work, we present an original approach based on the use of a novel architecture of precursors in the form of very thin free-standing solid silica fibers. An original technique called continuous fiberizing by laser melting (Cobiflas) was used to obtain membranes of pure silica fibers with diameters in the micrometer range, forming a porous membrane which offer a high surface and porous connectivity to be used as precursors without any supporting substrate. Then, we employed a method based on the impregnation of the silica fibers within a lithium-containing aqueous solution and subsequent calcination to obtain a porous solid adsorbent with the maximum proportion of lithium orthosilicate. This method is compared with the results obtained using a sol-gel powder method by analyzing their composition using X-Ray Diffraction (XRD), and their adsorption capacity and adsorption kinetics by Thermogravimetric analyses (TGA). As a result, an outstanding type of solid adsorbent is reported with a 31% adsorption capacity and a total regeneration capacity, which is over 0.8 efficiency with regard to the theoretical maximum adsorption of this material. Full article

Prostate cancer is the most common tumor in men in developed countries and it often responds poorly to conventional treatments. Monoclonal antibody (MoAb) therapy, for this pathology, has grown tremendously in the past decades, exploiting naked and conjugated antibodies to cytotoxic payloads to form antibody drug conjugates (ADCs). Several studies have been carried out conjugating biomolecules against prostate-specific membrane antigen (PSMA), highly expressed in this tumor, to cytotoxic drugs. Nano-based formulations show high potential in targeted drug delivery to enhance the bioavailability of drugs. Our research aimed to evaluate the feasibility of setting up a nanoparticle-based multimodal tool for targeted drug delivery, describing the step-by-step approach and to perform a first screening of these fluorescent PEGylated silica nanoparticles employed in selective cancer cell targeting and killing. These nanoparticles featured a core–shell structure to contemporarily conjugate the antibody and the cytotoxic payload monomethyl auristatin E (MMAE) using a step-by-step approach. We compared the cytotoxic effect of this multimodal nanotool near the antibody-MMAE and free MMAE. We found a lower cytotoxicity effect of the nanoparticle-based construct compared to free drugs, likely because of the preservation of the previously observed receptor-mediated endocytosis. Nanomedicine is confirmed as a powerful alternative to organic drug delivery systems, even if some aspects, such as drug loading efficacy, release, scalable manufacturing and long-term stability, need to be deepened. Full article

Guided bone regeneration (GBR) membrane has proven to be a fundamental tool in the realm of bone defect repair. In this study, we develop a mussel-inspired composite biomaterial through polydopamine-assisted, combining gelatin–WPU matrix with the ion-release behavior of Cu–MSNs for augmented bone regeneration. The optimized composite membrane exhibits enhanced mechanical stability, demonstrating a tensile strength of 11.23 MPa (representing a 2.3-fold increase compared to Bio-Gide^®), coupled with significantly slower degradation kinetics that retained 73.3% structural integrity after 35-day immersion in physiological solution. Copper ions act as angiogenic agents to promote blood vessel growth and as antimicrobial agents to prevent potential infections. The combined effect of these components creates a biomimetic environment that is ideal for cell adhesion, growth, and differentiation. This research significantly contributes to the development of advanced biomaterials that combine regeneration and infection-prevention functions. It provides a versatile and effective solution for treating bone injuries and defects, offering new hope for patients in need. Full article

Field horsetail (Equisetum arvense L.) is widely utilized in traditional medicine and is a rich source of bioactive compounds such as flavonoids, phenolic acids, and silica. This study investigates the protective effect of the polyphenolic extract from field horsetail (HLE) on erythrocytes and their cell membranes. The content of polyphenolic compounds in the extract was determined using the HPLC-DAD and Folin–Ciocalteu methods. The extract’s hemolytic activity, toxicity, antioxidant activity, and its impact on the physical properties of erythrocytes and lipid membrane were investigated. The antioxidant properties were evaluated using erythrocytes and isolated erythrocyte membranes oxidized by UVC radiation and AAPH. The impact of the extract on the ordering and fluidity of erythrocyte and model lipid membranes was studied. Furthermore, the transmembrane potential, shape of erythrocytes and the dipole potential of the lipid membranes under the influence of HLE were evaluated. The results indicated that HLE extract exhibited no toxicity to erythrocytes and HMEC-1 cells. HLE components effectively protect erythrocytes and their membranes against oxidation. They interact with the outer, polar surface of the erythrocyte membrane and reduce both erythrocyte membrane potential and lipid membrane dipole potential. The HLE polyphenols decrease the concentration of free radicals at the surface of the membrane, where they are located, and serve as a protective barrier, preventing penetration into the membrane. Full article

A sol-gel approach was used to prepare a thin hydrogel membrane based on an organic-inorganic polymer matrix embedded with pre-synthesized gold nanoparticles (AuNPs). The organic polymers utilized were poly(vinyl alcohol) (PVA) and poly(ethylene oxide) 400 (PEO) while tetraethoxysilane (TEOS) served as a precursor for the inorganic silica polymer. AuNPs were synthesized using D-glucose as a reducing agent and starch as a capping agent. A mixture of PVA, PEO, pre-hydrolyzed TEOS, and AuNP dispersions was cast and dried at 50 °C to obtain the hybrid hydrogel membrane. The structure, morphology, and optical properties of the nanocomposite membrane were analyzed using TEM, SEM, XRD, and UV-Vis spectroscopy. The newly designed hybrid hydrogel membrane was utilized as an efficient sorbent for the simultaneous speciation analysis of valence species of chromium and manganese in water samples via solid-phase extraction. This study revealed that Cr(III) and Mn(II) could be simultaneously adsorbed onto the PVA/PEO/SiO₂/AuNP membrane at pH 9 while Cr(VI) and Mn(VII) remained in solution due to their inability to bind under these conditions. Under optimized parameters, detection limits and relative standard deviations were determined for chromium and manganese species. The developed analytical method was successfully applied for the simultaneous speciation analysis of chromium and manganese in drinking water and wastewater samples. Full article

For industrial CO₂ utilization, the supply of concentrated CO₂ within a continuous, high-volume stream at high temperatures remains a substantial requirement. Membrane processes offer a simple and efficient method to provide CO₂ in this form. While several organo-silica-based membranes have been developed for CO₂/N₂ separation under these conditions, there is no standardized framework guiding comparability and optimization. Therefore, we present these membranes in a Robeson-like plot across various temperatures. Utilizing a standard 1,2-bis(triethoxysilyl)-ethane (BTESE) precursor and a simplified sol–gel method, we prepared a microporous membrane layer and characterized it for an exemplary comparison. This characterization includes key parameters for mixed-gas applications: (1) temperature-dependent single- and mixed-gas permeances to observe interactions, (2) the impact of the driving forces in mixtures (vacuum and concentration) to distinguish between permselectivity and the separation factor clearly, and (3) influence of the support structure to enable permeability calculations at elevated temperatures. Furthermore, a quick interpretation method for assessing the membrane’s microstructure is presented. A qualitative microstructure assessment can be achieved by analyzing the temperature dependencies of the three major diffusion mechanisms that simultaneously occur—Knudsen, surface, and activated diffusion. Full article