Search Results (103)

In this study, we report the synthesis and characterization of a novel NH₂-MIL-101(Fe) magnetic composite, developed via in situ formation of NH₂-MIL-101(Fe) in the presence of Fe₃O₄ nanoparticles embedded within a chloropropyl-modified mesoporous silica layer. This hybrid composite retains the high adsorption capacity of NH₂-MIL-101(Fe) while benefiting from the easy magnetic separation enabled by Fe₃O₄ nanoparticles. The mesoporous silica forms a protective porous coating around the magnetic nanoparticles, significantly enhancing its chemical stability and preventing clumping. Beyond protection, the mesoporous silica layer provides a high-surface-area scaffold that promotes the uniform in situ growth of NH₂-MIL-101(Fe). Functionalization of the silica surface with chloride groups enables strong electrostatic interactions between the magnetic component and metal organic framework (MOF), ensuring a homogeneous and stable hybrid structure. The new composite’s capacity to remove Pb(II) and Cd(II) ions from aqueous solutions was systematically investigated. The adsorption data showed a good fit with the Langmuir isotherm model for both ions, the maximum adsorption capacities calculated being 214.6 mg g⁻¹ for Pb(II) and 181.6 mg g⁻¹ Cd(II). Furthermore, the kinetic behavior of the adsorption process was accurately described by the pseudo-second-order model. These findings confirm the effectiveness of this composite for the removal of Pb(II) and Cd(II) ions from aqueous solutions, demonstrating its potential as an efficient material for environmental remediation. The combination of magnetic recovery, high adsorption capacity, and stability makes this novel composite a promising candidate for heavy metal removal applications in water treatment processes. Full article

The development of mineral, biodegradable sunscreens that can offer both high photoprotection and long-term colloidal stability, while limiting synthetic additives, presents a significant challenge. A linseed oil nanoemulsion co-stabilised by ZnO nanoparticles and the eco-friendly surfactant Appyclean 6552 was formulated, and the effect of incorporating fumed silica/alumina (Aerosil COK 84) was evaluated. A central composite response surface design was used to ascertain the oil/ZnO ratio that maximised the in vitro sun protection factor at sub-300 nm droplet size. The incorporation of Aerosil at concentrations ranging from 0 to 2 wt.% resulted in a transformation of the dispersion from a nearly Newtonian state to a weak-gel behaviour. This alteration was accompanied by a reduction in the Turbiscan Stability Index. Microscopic analysis has revealed a hierarchical particle architecture, in which ZnO forms Pickering shells around each droplet, while Aerosil aggregates bridge neighboring interfaces, creating a percolated silica scaffold that immobilises droplets and amplifies multiple UV scattering. The findings demonstrate that coupling interfacial Pickering armour with a continuous silica network yields a greener, physically robust mineral sunscreen and offers a transferable strategy for stabilising plant-oil emulsions containing inorganic actives. Full article

UV-cured methacrylated chitosan (MCHIT) hydrogels were achieved in the presence of silanised tellurium-doped silica bioactive glass (BG-Te-Sil) to produce an antimicrobial and osteoconductive scaffold for tissue engineering applications. Methacrylation of chitosan enabled efficient crosslinking, and the curing process was evaluated by means of Fourier-transform infrared spectroscopy (FTIR) and photorheology analyses. Compressive testing on crosslinked hydrogels showed that the silanised, bioactive, doped glass increased the hydrogel’s elastic modulus by up to 200% compared to unreinforced controls. Antibacterial assays against Staphylococcus aureus ATCC 43300 revealed a significant (p < 0.05) reduction in bacterial metabolic activity for hydrogels containing 50 wt% of the Te-doped bioactive glass. In vitro cytocompatibility with human bone-marrow mesenchymal stem cells demonstrated sustained viability and uniform distribution at 72 h (live/dead staining, AlamarBlue). Under H₂O₂-induced oxidative stress, reinforced hydrogels downregulated pro-inflammatory genes (TNF-α, IFN-γ, IL-1β, and PGES-2). These results suggest that the presence of the silanised bioactive glass can significantly enhance mechanical stability, antibacterial properties, and anti-inflammatory responses without affecting cytocompatibility, making these hydrogels promising for tissue engineering applications. Full article

Nanotopography refers to the intricate surface characteristics of materials at the sub-micron (<1000 nm) and nanometer (<100 nm) scales. These topographical surface features significantly influence the physical, chemical, and biological properties of biomaterials, affecting their interactions with cells and surrounding tissues. The development of nanostructured surfaces of polymeric nanocomposites has garnered increasing attention in the fields of tissue engineering and regenerative medicine due to their ability to modulate cellular responses and enhance tissue regeneration. Various top-down and bottom-up techniques, including nanolithography, etching, deposition, laser ablation, template-assisted synthesis, and nanografting techniques, are employed to create structured surfaces on biomaterials. Additionally, nanotopographies can be fabricated using polymeric nanocomposites, with or without the integration of organic and inorganic nanomaterials, through advanced methods such as using electrospinning, layer-by-layer (LbL) assembly, sol–gel processing, in situ polymerization, 3D printing, template-assisted methods, and spin coating. The surface topography of polymeric nanocomposite scaffolds can be tailored through the incorporation of organic nanomaterials (e.g., chitosan, dextran, alginate, collagen, polydopamine, cellulose, polypyrrole) and inorganic nanomaterials (e.g., silver, gold, titania, silica, zirconia, iron oxide). The choice of fabrication technique depends on the desired surface features, material properties, and specific biomedical applications. Nanotopographical modifications on biomaterials’ surface play a crucial role in regulating cell behavior, including adhesion, proliferation, differentiation, and migration, which are critical for tissue engineering and repair. For effective tissue regeneration, it is imperative that scaffolds closely mimic the native extracellular matrix (ECM), providing a mechanical framework and topographical cues that replicate matrix elasticity and nanoscale surface features. This ECM biomimicry is vital for responding to biochemical signaling cues, orchestrating cellular functions, metabolic processes, and subsequent tissue organization. The integration of nanotopography within scaffold matrices has emerged as a pivotal regulator in the development of next-generation biomaterials designed to regulate cellular responses for enhanced tissue repair and organization. Additionally, these scaffolds with specific surface topographies, such as grooves (linear channels that guide cell alignment), pillars (protrusions), holes/pits/dots (depressions), fibrous structures (mimicking ECM fibers), and tubular arrays (array of tubular structures), are crucial for regulating cell behavior and promoting tissue repair. This review presents recent advances in the fabrication methodologies used to engineer nanotopographical microenvironments in polymeric nanocomposite tissue scaffolds through the incorporation of nanomaterials and biomolecular functionalization. Furthermore, it discusses how these modifications influence cellular interactions and tissue regeneration. Finally, the review highlights the challenges and future perspectives in nanomaterial-mediated fabrication of nanotopographical polymeric scaffolds for tissue engineering and regenerative medicine. Full article

Background/Objectives: The isatin nucleus is a privileged scaffold in drug discovery, particularly due to its proven relevance in anticancer research. Developing reusable heterogeneous 3D catalysts for drug synthesis represents a critical challenge in both industrial and academic contexts. This multi and interdisciplinary work aimed to design and synthesize a novel 3D-printed silica-based porous catalyst functionalized with palladium, evaluate its catalytic performance in isatin drug synthesis, and assess the antiproliferative activity of the resulting compounds against tumor cell lines such as HeLa, MCF-7, and MDA-MB231. Methods: The novel multifaceted approach to synthesizing this heterogeneous catalyst involved the surface growth of a metal–organic framework (ZIF-8) on 3D-printed silica support, followed by potassium silicate coating and pyrolysis. Results: After detailed physicochemical characterization, the catalyst was tested in challenging “double” palladium-catalyzed cross-coupling reactions (Suzuki, Stille, and Heck), demonstrating robustness, reusability, and high efficiency in producing bis-1,5-aryl, alkynyl, and alkenyl-isatin derivatives. Importantly, no leaching of palladium species was detected during the catalytic cycles, further underscoring the stability of the system. These isatin-based compounds exhibited remarkable cytotoxicity, with selective molecules achieving nanomolar potency against MCF-7 cells, surpassing reference drugs such as doxorubicin and sunitinib. Conclusions: This study not only introduces a novel strategy for fabricating porous heterogeneous catalysts from sintered surfaces but also highlights new biomolecules with promising applications in cancer research. Full article

We report the design and development of a novel multifunctional nanostructure, RB-AuSiO₂_HSA-DOX, where tri-modal cancer treatment strategies—photothermal therapy (PTT), photodynamic therapy (PDT), chemotherapy—luminescent properties and targeting are integrated into the same scaffold. It consists of a gold core with optical and thermo-plasmonic properties and is covered by a silica shell entrapping a well-known photosensitizer and luminophore, Rose Bengal (RB). The nanoparticle surface was decorated with Human Serum Albumin (HSA) through a covalent conjugation to confer its targeting abilities and as a carrier of Doxorubicin (DOX), one of the most effective anticancer drugs in clinical chemotherapy. The obtained nanostructure was fully characterized through transmission electron microscopy (TEM), dynamic light scattering (DLS) and UV-visible spectroscopy, with a homogeneous and spherical shape, an average diameter of about 60 nm and negative ζ-potential value Singlet oxygen generation and photothermal properties were explored under green light irradiation. The interaction between DOX-HSA anchored on the nanoplatform was investigated by fluorescence spectroscopy and compared to that of DOX-HSA, pointing out different accessibility of the drug molecules to the HSA binding sites, whether the protein is free or bound to the nanoparticle surface. To the best of our knowledge, there are no studies comparing a drug–HSA interaction with that of the same protein anchored to nanoparticles. Furthermore, the uptake of RB-AuSiO₂_HSA-DOX into MDA-MB-231 mammary cells was assessed by confocal imaging, highlighting—at early time of incubation and as demonstrated by the increased DOX luminescence displayed within cells—a better internalization of the carried anticancer drug compared to the free one, making the obtained nanostructure a suitable and promising platform for an anticancer multimodal approach. Full article

We have investigated the thermodynamic property modification of ammonia borane via nanoconfinement. Two different mesoporous silica scaffolds, SBA-15 and MCM-41, were used to confine ammonia borane. Using in situ Raman spectroscopy, we examined how pore size influences the phase transition temperature from tetragonal (I4mm) to orthorhombic (Pmn21) for ammonia borane. In bulk ammonia borane, the phase transition occurs at around 217 K; however, confinement in SBA-15 (with ~8 nm pore sizes) reduces this temperature to approximately 195 K, while confinement in MCM-41 (with pore sizes of 2.1–2.7 nm) further lowers it to below 90 K. This suppression of the phase transition as a function of pore size has not been previously studied using Raman spectroscopy. The stability of the I4mm phase at a much lower temperature can be interpreted by incorporating the surface energy terms to the overall free energy of the system in a simple thermodynamic model, which leads to a significant increase in the surface energy when transitioning from the tetragonal phase to the orthorhombic phase. Full article

This study explores the development of biocompatible scaffolds for bone regeneration, utilizing polylactic acid (PLA) combined with calcium phosphate as a pH buffer and diatomaceous earth as a biocompatibilizer. These materials were extruded and 3D-printed to enhance cell adhesion and biodegradability after enough cell growth. The biocompatibility of the resulting composites, with different proportions of the components and sterilization methods, was tested according to the ISO 10993 protocol. The optimal performance, with nearly zero cytotoxicity, was observed with 20 PLA/1 CP/1 DE mass ratios and gamma sterilization. Tension analysis and scanning electron microscopy (SEM) were applied to the 3D-printed composites, which were also analyzed by differential scanning calorimetry (DSC) to understand the origin of the tension properties better, which were comparable to those of cancellous bone. Degradation tests under physiological conditions for 13 weeks showed no significant mass loss. Furthermore, it was observed that cell adhesion, viability, proliferation, and osteoconduction are possible in the scaffolds studied, opening opportunities for future studies to substantiate the use of 3D-printed silica-filled composites as an alternative to homologous implants for various bone regeneration applications. Full article

Due to their nature, using shear thickening fluids (STFs) in engineering applications has sparked an interest in developing energy-dissipating systems, such as damping devices or shock absorbers. The Rheinforce technology allows the design of customized energy dissipative composites by embedding microfluidic channels filled with STFs in a scaffold material. One of the reasons for using microfluidic channels is that their shape can be numerically optimized to control pressure drop (also known as rectifiers); thus, by controlling the pressure drop, it is possible to control the energy dissipated by the viscous effect. Upon impact, the fluid is forced to flow through the microchannel, experiencing the typical entry flow until it reaches the fully developed flow. It is well-known for Newtonian fluid that the entrance flow is responsible for a non-negligible percentage of the total pressure drop in the fluid; therefore, an analysis of the fluid flow at the entry region for STFs is of paramount importance for an accurate design of the Rheinforce composites. This analysis has been numerically performed before for shear-thickening fluids modeled by a power-law model; however, as this constitutive model represents a continuously growing viscosity between end-viscosity plateau values, it is not representative of the characteristic viscosity curve of shear-thickening fluids, which typically exhibit a three-region shape (thinning-thickening-thinning). For the first time, the influence of these three regions on the entry flow on an axisymmetric pipe is analyzed. Two-dimensional numerical simulations have been performed for four STFs consisting of four dispersions of fumed silica nanoparticles in polypropylene glycol varying concentrations (7.5–20 wt%). Full article

Fabricating large-scale porous bioactive glass bone scaffolds presents significant challenges. This study aims to develop formable, in situ setting scaffolds with a practical gelation time of about 10 min by mixing 45S5 bioactive glass with sodium silicate (waterglass) and an acid initiator. The effects of pH (2–11), waterglass concentration (15–50 wt.%), and acid initiator type (phosphoric or boric acid) were examined to optimize gelation kinetics and microstructure. A 10 min gelation time was achieved with boric acid and phosphoric acid at various pH levels by adjusting the waterglass concentration. Exponential and polynomial models were proposed to predict gelation times in basic and acidic environments, respectively. The optical properties of the gels were studied qualitatively and quantitatively, providing insights into gelation kinetics and structure. Acidic gels formed smaller particles in a dense network (pores < 550 nm) with higher light transmittance, while basic gels had larger aggregates (pores ~5 µm) and lower transmittance. As the waterglass concentration decreased, pore size and transmittance converged in both groups. The onset of gelation was detected around 8 min using the derivative of light transmittance. This work identifies the key factors controlling waterglass gelation and their impact on gel structure, enabling the tailored creation of formable, in situ setting bioactive glass bone scaffolds. Full article

Repairing or reconstructing significant bone defects is typically challenging. In the present study, two composite cements were used as scaffolds in a sub-critical femoral defect in rats. A control group and two experimental batches were used to compare the outcomes. This research aimed to investigate the osteogenic potential and toxicological tolerance of the bioproducts through histopathology and computed tomography imaging analysis at 14, 28, 56, and 90 days post-implantation. The biomaterials used in the investigation consisted of a 65% bioactive salinized inorganic filler and a 25% weight organic matrix. The organic part of the biomaterial was composed of Bis-GMA (bisphenol A-glycidyl methacrylate), UDMA (urethane dimethacrylate), HEMA (2-Hydroxyethyl methacrylate), and TEGDMA (triethylene glycol dimethacrylate), while the inorganic filler was composed of silica, barium glass, hydroxyapatite, and fluor aluminosilicate glass. The first findings of this research are encouraging, revealing that there is a slight difference between the groups treated with biomaterials, but it might be an effective approach for managing bone abnormalities. Material C1 exhibited a faster bone defect healing time compared to material C2, where bone fractures occurred in some individuals. It is unclear if the fractures were caused by the presence of the biomaterial C2 or whether additional variables were to blame. By the end of the research, the mice appeared to tolerate the biomaterials without exhibiting any inflammatory or rejection responses. Full article

Synthetic efforts toward complex natural product (NP) scaffolds are useful ones, particularly those aimed at expanding their bioactive chemical space. Here, we utilised an orthogonal cheminformatics-based approach to predict the potential biological activities for a series of synthetic bis-indole alkaloids inspired by elusive sponge-derived NPs, echinosulfone A (1) and echinosulfonic acids A–D (2–5). Our work includes the first synthesis of desulfato-echinosulfonic acid C, an α-hydroxy bis(3′-indolyl) alkaloid (17), and its full NMR characterisation. This synthesis provides corroborating evidence for the structure revision of echinosulfonic acids A-C. Additionally, we demonstrate a robust synthetic strategy toward a diverse range of α-methine bis(3′-indolyl) acids and acetates (11–16) without the need for silica-based purification in either one or two steps. By integrating our synthetic library of bis-indoles with bioactivity data for 2048 marine indole alkaloids (reported up to the end of 2021), we analyzed their overlap with marine natural product chemical diversity. Notably, the C-6 dibrominated α-hydroxy bis(3′-indolyl) and α-methine bis(3′-indolyl) analogues (11, 14, and 17) were found to contain significant overlap with antibacterial C-6 dibrominated marine bis-indoles, guiding our biological evaluation. Validating the results of our cheminformatics analyses, the dibrominated α-methine bis(3′-indolyl) alkaloids (11, 12, 14, and 15) were found to exhibit antibacterial activities against methicillin-sensitive and -resistant Staphylococcus aureus. Further, while investigating other synthetic approaches toward bis-indole alkaloids, 16 incorrectly assigned synthetic α-hydroxy bis(3′-indolyl) alkaloids were identified. After careful analysis of their reported NMR data, and comparison with those obtained for the synthetic bis-indoles reported herein, all of the structures have been revised to α-methine bis(3′-indolyl) alkaloids. Full article

The paradigm of regenerative medicine is undergoing a transformative shift with the emergence of nanoengineered silica-based biomaterials. Their unique confluence of biocompatibility, precisely tunable porosity, and the ability to modulate cellular behavior at the molecular level makes them highly desirable for diverse tissue repair and regeneration applications. Advancements in nanoengineered silica synthesis and functionalization techniques have yielded a new generation of versatile biomaterials with tailored functionalities for targeted drug delivery, biomimetic scaffolds, and integration with stem cell therapy. These functionalities hold the potential to optimize therapeutic efficacy, promote enhanced regeneration, and modulate stem cell behavior for improved regenerative outcomes. Furthermore, the unique properties of silica facilitate non-invasive diagnostics and treatment monitoring through advanced biomedical imaging techniques, enabling a more holistic approach to regenerative medicine. This review comprehensively examines the utilization of nanoengineered silica biomaterials for diverse applications in regenerative medicine. By critically appraising the fabrication and design strategies that govern engineered silica biomaterials, this review underscores their groundbreaking potential to bridge the gap between the vision of regenerative medicine and clinical reality. Full article

Magnesium silicate ceramics are promising materials for bone tissue regeneration and can be prepared through 3D printing of magnesium oxide/silica (MgO/SiO₂) cement pastes followed by calcination. Despite the growing interest in these formulations, additive manufacturing technology has only recently been explored for these cements, and the effects of admixtures and additives on such printing inks remain largely unexplored. In this study, we prepared various MgO/SiO₂ cement formulations with differing amounts of sodium orthophosphate, a setting retarder, and cellulose ethers, used as rheo-modifiers. The samples’ setting properties were investigated, and printing parameters were properly adjusted. The most promising formulations were then 3D printed and calcined to obtain forsterite bioceramics, which were further characterized using confocal Raman microscopy, scanning electron microscopy, atomic force microscopy, gas porosimetry, and compressive strength tests. Our results revealed that the cellulose derivatives influence the printability of the MgO/SiO₂ formulations without affecting the hardening time, which can be adjusted by the addition of sodium phosphate. The use of fine-tuned formulations allowed for the preparation of 3D-printed forsterite bioceramics, potentially suitable for biological applications as cancellous bone scaffolds. Full article

Inorganic–organic hybrid biomaterials have been proposed for bone tissue repair, with improved mechanical flexibility compared with scaffolds fabricated from bioceramics. However, obtaining hybrids with osteoinductive properties equivalent to those of bioceramics is still a challenge. In this work, we present for the first time the synthesis of a class II hybrid modified with bioactive glass nanoparticles (nBGs) with osteoinductive properties. The nanocomposite hybrids were produced by incorporating nBGs in situ into a polytetrahydrofuran (PTHF) and silica (SiO₂) hybrid synthesis mixture using a combined sol–gel and cationic polymerization method. nBGs ~80 nm in size were synthesized using the sol–gel technique. The structure, composition, morphology, and mechanical properties of the resulting materials were characterized using ATR-FTIR, ²⁹Si MAS NMR, SEM-EDX, AFM, TGA, DSC, mechanical, and DMA testing. The in vitro bioactivity and degradability of the hybrids were assessed in simulated body fluid (SBF) and PBS, respectively. Cytocompatibility with mesenchymal stem cells was assessed using MTS and cell adhesion assays. Osteogenic differentiation was determined using the alkaline phosphatase activity (ALP), as well as the gene expression of Runx2 and Osterix markers. Hybrids loaded with 5, 10, and 15% of nBGs retained the mechanical flexibility of the PTHF–SiO₂ matrix and improved its ability to promote the formation of bone-like apatite in SBF. The nBGs did not impair cell viability, increased the ALP activity, and upregulated the expression of Runx2 and Osterix. These results demonstrate that nBGs are an effective osteoinductive nanoadditive for the production of class II hybrid materials with enhanced properties for bone tissue regeneration. Full article