Curcumin, a natural polyphenolic compound with well-documented anti-inflammatory, antioxidant, and anticancer properties, has gained attention for its potential in tissue regeneration and other biomedical applications. Despite this, the integration of curcumin into polymeric scaffolds remains challenging due to its hydrophobic nature and stability concerns. This study aims to overcome these limitations by developing and characterizing curcumin-loaded polycaprolactone (PCL) scaffolds through electrospinning, a technique selected based on a comprehensive review of recent advances in the field. In this work, PCL scaffolds were fabricated with curcumin concentrations of 5, 10, and 15 mg and analyzed using advanced microscopy, spectroscopy, thermogravimetry, mechanical testing, and biological assays. Microscopy revealed that increasing curcumin concentrations improved fiber diameter uniformity and distribution. Raman spectroscopy confirmed the homogeneous incorporation of curcumin within the scaffolds, showing that up to 10 mg, the electrospinning process induces a transition of curcumin from its di-keto to its more reactive keto-enol form. This transformation facilitates hydrogen bonding with the PCL matrix, enhancing the scaffolds' mechanical properties. In vitro cytotoxicity assays demonstrated high cell viability across all scaffolds after 24 and 72 h. Furthermore, adhesion studies with fibroblast BJ-1 cells indicated significantly improved cell adhesion on curcumin-loaded scaffolds compared to pure PCL. These findings highlight the biocompatibility and bioactivity of curcuminloaded PCL scaffolds. This study examines the possible use of curcumin's controlled integration into PCL scaffolds for tissue regeneration applications. The innovative approach detailed here offers a scalable and effective pathway for the development of biomaterials that combine mechanical strength, bioactivity, and biocompatibility, addressing a critical need in tissue engineering.

Electrospun fibrous scaffolds based on cellulose acetate (CA), polycaprolactone (PCL), and poly (L-lactic acid) (PLLA) are versatile materials with applications spanning diverse fields, but in their pristine form, they typically lack significant inherent antibacterial properties. To address this limitation and expand their utility, this study explored the incorporation of xylitol, a natural antibacterial sugar alcohol, into these polymer matrices to enhance their physicochemical and antimicrobial properties. Electrospinning was employed to fabricate pristine and xylitol-loaded scaffolds with varying xylitol concentrations. Morphological analysis revealed polymer-dependent changes in fiber diameter and porosity. Mechanical testing assessed the impact of xylitol on tensile properties, while thermal analysis investigated alterations in melting temperature and crystallinity. The antibacterial efficacy against Staphylococcus aureus and Escherichia coli was evaluated using WST assay and live/dead staining. Notably, xylitol significantly enhanced the antibacterial activity against both bacterial species, with a more pronounced and rapid effect observed against S. aureus. The tailored scaffold properties and imparted antimicrobial characteristics highlight the potential of these xylitol-modified electrospun materials: they are easily produced, low-cost, and appropriate for a range of applications (dental applications, filters, masks, wound dressing, and packaging) where preventing bacterial contamination is crucial.

Due to anatomical and biological similarities with humans, pigs are increasingly used for inflammation- and immune -related studies in biomedical research, including the field of osteonecrosis and osteoimmunology. Here, we present a protocol for rib extraction, isolation of the bone marrow by centrifugation, and processing to obtain bone -marrow -derived macrophages (BMDMs). Then, we describe the procedures of in vitro experiments to evaluate the cell phenotype. For complete details on the use and execution of this protocol, please refer to Andre et al. 1

The commercial use of Si3N4 ceramics in the biomedical field dates back to the early 1980s and, initially, did not show promising results, which is why their biocompatibility was not then investigated further until about 10 years later. Over the years, a change in trend has been observed; more and more studies have shown that this material could possess high biocompatibility and antibacterial properties. However, the relevant literature struggles to find mechanisms that can incontrovertibly explain the reasons behind the biological activity of Si3N4. The proposed mechanisms are often pure hypotheses or are not substantiated by comprehensive analyses. This review begins by studying the early references to the biological activity of Si3N4 and then reviews the literature regarding the bioactivity of this ceramic over time. An examination of the early insights into surface chemistry and biocompatibility lays the foundation for a detailed examination of the chemical reactions that Si3N4 undergoes in biological environments. Next, the analysis focuses on the mechanisms of bioactivity and antipathogenicity that the material exhibits both alone and in combination with modern bioglass. However, it is highlighted that despite the general consensus on the biocompatibility and bioactivity of Si3N4 ceramics, sometimes the proposed biological mechanisms behind its behavior are discordant or unsupported by the direct evaluation of specific biochemical activities. This review highlights both the reliable information in the literature and the gaps in research that need to be filled in order to fully understand the reasons behind the biological properties of this material.

By making use of the outstanding osteoinductive effects of beta-carotene, in this innovative research, we investigate the potential for application of beta-carotene-reinforced PMMA resins. Different amounts of beta-carotene, from 0% to 5%, have been mixed with standard bone cements and characterized by various spectroscopic and microscopic techniques before testing with KUSA-A1 murine mesenchymal cells. In vitro results showed that not only the amount of bone produced by the cells on the composite is comparable if not superior to modern bioglasses but also both adhesion and cellular proliferation are strongly promoted by the presence of beta-carotene. The increased biological properties came at the price of a small loss in elastic modulus, but it was observed that the presence of beta-carotene leads to an increase of ultimate strength, reaching an increase of about 30% at a concentration of about 2.5%. The enhanced bioactivity and mechanical strength make beta-carotene-reinforced PMMA a promising, innovative material for biomedical applications.

In this study, electrospun scaffolds were fabricated using polycaprolactone (PCL) loaded with varying concentrations of β-carotene (1.2%, 2.4%, and 3.6%) via the electrospinning technique. The electrospinning process involved the melting of PCL in acetic acid, followed by the incorporation of β-carotene powder under constant stirring. Raman spectroscopy revealed a homogeneous distribution of β-carotene within the PCL matrix. However, the β-carotene appeared in particulate form, rather than being dissolved and blended with the PCL matrix, a result also confirmed by thermogravimetric analysis. Additionally, X-ray diffraction analysis indicated a decrease in crystallinity with increasing β-carotene concentration. Mechanical testing of the scaffolds demonstrated an increase in ultimate strain, accompanied by a reduction in ultimate stress, indicating a potential plasticizing effect. Moreover, antimicrobial assays revealed a marginal antibacterial effect against Escherichia coli for scaffolds with higher β-carotene concentrations. Conversely, preliminary biological assessment using KUSA-A1 mesenchymal cells indicated enhanced cellular proliferation in response to the scaffolds, suggesting the potential biocompatibility and cell-stimulating properties of β-carotene-loaded PCL scaffolds. Overall, this study provides insights into the fabrication and characterization of electrospun PCL scaffolds containing β-carotene, laying the groundwork for further exploration in tissue engineering and regenerative medicine applications.

Yttria stabilized zirconia, one of the most common ceramics in the field of dentistry and in particular dental implantology, for decades has been wrongly considered to be completely bio-inert. In this work, we investigate the role of yttria on the bioactivity of yttria stabilized zirconia formulations, proving that the composite ceramic is actually bioactive, do not affect the cell adhesion and can stimulate cell proliferation, in vitro. To reduce to minimum the number of variables, yttria stabilized zirconia particles with different contents of yttria but similar average size and morphology have been used to reinforce an electrospun poly-l-lactide (PLLA) fibers. Characterization of both the ceramic particulates and the scaffolds confirmed the morphological and structural similarities between the samples, which were then tested in vitro using a human fetal osteoblasts model. The results showed that cell proliferation is enhanced by the presence of the composite ceramic additive, with higher contents of yttria being overall more effective. These results confirm that yttria plays a key role in the biocompatibility and bioactivity of ceramics and can be used to improve the chances for a positive outcome in the osteo-integration of dental implants and/or biomedical scaffolds.

In recent years, silicon nitride (Si3N4) ceramics have gained popularity as bioactive structural materials with the capability to stimulate cell proliferation and fight pathogens. Despite displaying bioactive properties and having an excellent mechanical strength, the number of possible applications for silicon nitride is somehow limited by its brittle nature and high production costs. In this work, particles of Si3N4 have been added to Poly(methyl metachylate) (PMMA) bone cements to verify how this reinforcement influences mechanical and antibacterial properties. 5, 10 and 15% weight fractions of powders with average mesh size 25, 50 and 300 μm were mixed together with PMMA and molded into testing samples. Results of the in vitro testing with Escherichia coli and Staphylococcus epidermidis showed that the antibacterial effects of Si3N4 correlate positively with the fraction of ceramic used and are negatively correlated with the mesh size of the powders. Moreover, the smaller particles at the lowest concentration acted as a mechanical reinforcement, increasing the ultimate tensile strength of the composite by about 10%.

Acrylic resin (PMMA -polymethylmethacrylate) is a material widely used in orthopedics to fill gaps or cavities in the bone marrow, bone defects, and implants fixation. However, even if it possesses high mechanical strength and is considered bioinert, its use has various limitations related to the lack of positive additional bioactive effects, such as osteogenesis stimulation. This work reports a preliminary assessment of the effects of curcumin incorporated in PMMA bone cements at different concentrations (4, 5, 7.5, and 10 wt%), and in particular, its osteoinductivity and osteoconductivity in vitro, tested with KUSA-A1 cells. The different samples were characterized using a combination of microscopic and spectroscopic techniques before and after in vitro testing. Results showed that curcumin and PMMA can produce a homogeneous composite material in a wide range of concentrations, up to at least 10 wt%. By increasing the percentage of curcumin both cellular adhesion and bone production are improved, without sacrificing the quality of the bone tissue formed. Addition of curcumin over a threshold of about 5% results in a sudden loss of ultimate strength with an increase of the elongation to failure. Samples containing about 5% of curcumin proved to have good in vitro performances without compromising the mechanical properties. This suggests how curcumin can be considered as a low-cost additive useful not only for its well-known antimicrobial activity but also in the bone regeneration improving the bioactive properties of the PMMA.(c) 2022 Elsevier Ltd. All rights reserved.

Polymethyl methacrylate (PMMA) bone cements are used as “glue” between orthopedic/orthodontic implants and bone, since they can be modeled and easily applied by the surgeon, while being chemically and biologically stable for many years after surgery. In this research, Y2O3 powder was added to commercial PMMA bone cement to produce a composite resin, which was then characterized and tested in vitro to evaluate the cell proliferation and the quality of osteoblastic bone formed in vitro on the composite. Biological assays showed an increase in cell proliferation on the Y2O3-PMMA composite as compared to the pristine sample. Alizarin Red staining (ARS) showed the amount of bone formed on a composite PMMA resin was about 30% higher than that on the pristine PMMA bone cement reference. The quality of bone tissue was evaluated using Raman spectroscopy, showing the bone tissue formed on the composite had a better degree of mineralization and a higher maturity as compared to the tissue grown on the control sample. These preliminary results suggest that Y2O3 plays a biologically active role in bone growth and Y2O3-composites are affordable, superior candidates as bone cement materials.

High-precision poly(L-lactic acid) (PLLA) scaffold fabricated by melt electrowriting (MEW) as a bone substitute was investigated, however, the inherent fragility and the low bioactivity of the scaffold impede its clinical application. In this context, a biomimetic reinforced composite scaffold combining the MEW PLLA lattice with gelatin/genipin/bioglass hydrogel is firstly proposed. Incorporating with 1 wt% bioglass, the composite scaffold shows excellent interconnectivity, high storage modulus (121.3 kPa, 1.3 times of gelatin/genipin) and improved storage modulus (422.3 kPa). Moreover, this reinforced scaffold displays elevated in vitro osteoinduction/conduction capability, high amount of bone tissue formation and a prime Ca/P ratio of 1.69 (as compared with natural bone with Ca/P ratio of 1.67). The mechanisms of the enhanced mechanical properties and the variation of bone formation ability of various scaffolds are elucidated by a potential model. This study gives insights into some potential innovative strategies for using MEW PLLA scaffold to achieve unprecedented results in bone regeneration.

Poly-caprolactone is one of the most promising biocompatible polymers on the market, in particular for temporary devices that are not subjected to high physiological loads. Even if completely resorbable in various biological environments, poly-caprolactione does not play any specific biological role in supporting tissue regeneration and for this reason has a limited range of possible applications. In this preliminary work, for the first time l-dopa and fibroin have been combined with electrospun poly-caprolactone fibers in order to induce bioactive effects and, in particular, stimulate the proliferation, adhesion and osteoconduction of the polymeric fibers. Results showed that addition of low-molecular weight fibroin reduces the mechanical strength of the fibers while promoting the formation of mineralized deposits, when testedin vitrowith KUSA-A1 mesenchymal cells. l-dopa, on the other hand, improved the mechanical properties and stimulated the formation of agglomerates of mineralized deposits containing calcium and phosphorous with high specific volume. The combination of the two substances resulted in good mechanical properties and higher amounts of mineralized deposits formedin vitro.

The bone resorption inhibitor bisphosphonate (BP) is used to prevent fractures in patients with osteoporosis and bone metastases caused by cancer. However, BP induces apoptosis of osteoclasts and excessively suppresses bone turnover, so that side effects such as jawbone necrosis have become a problem. In the super-aging society that Japan is facing, it is expected that jawbone necrosis (Medication-related osteonecrosis of the jaw: MRONJ) will increase as the number of osteoporosis patients increases. There are many unclear points about the pathophysiology of jawbone necrosis, and there have been attempts to clarify it. Most of the research on osteoclasts so far has comprised destructive and invasive analyses, such as TRAP staining and PCR by culturing osteoclasts on a plastic plate, which is the original physiological function of osteoclasts. “Bone resorption” cannot be analyzed in real time. In this study, Raman spectroscopy is used to show the state of bone resorption of osteoclasts cultured on ivory sections or octacalcium phosphate plates noninvasively and without the need for colorimetric assays. This makes it possible to clarify the effect of BP on osteoclast metabolism in an environment closer to that of a living body. If this method is established, then we aim to elucidate the pathophysiology of bone pathologies and medical treatments that directly affect osteoclasts, such as medication-related osteonecrosis, and establish a diagnostic method.

Following the rising interested on 3D-printed technologies, this research explores the possibility to use stereo-lithography to 3D print PMMA resins reinforced with up to 15% in weight of antibacterial ceramic powders. Three different reinforcements were tested, following previous literature data: aluminum nitride, titanium oxide and barium titanate. Between the three powders, the most uniform dispersion was achieved using aluminum nitride. Initial screenings with mixed and cured composite resins showed that between the three composite materials, only aluminum nitride and barium titanate PMMA possess a marked antibacterial effect when compared to the pristine reference, with aluminum nitride being the most effective against E. coli and resulting in a 30–60% decrease in WST optical density. When 3D printed using stereo-lithography, the composite containing aluminum nitride showed an even higher degree of dispersion and comparable antibacterial effects, as also confirmed by a reduction of colony forming units of up to about 70%. Moreover, aluminum nitride reinforced PMMA resins showed good mechanical properties, losing only about 12% of ultimate strength for ceramic fractions of 15%, while retaining the ability to be further strengthened by a standard post-curing process.

While joint arthroplasty remains nowadays the most popular option available to repair chronically degenerated osteoarthritic joints, possibilities are recently emerging for regeneration of damaged cartilage rather than its replacement with artificial biomaterials. This latter strategy could allow avoiding the quite intrusive surgical procedures associated with total joint replacement. Building upon this notion, we first apply Raman spectroscopy to characterize diseased cartilage in a mice model of instability-induced knee osteoarthritis (OA) upon medial collateral ligament (MCL) and medial meniscus (MM) transections. Then, we examine the same OA model after cartilage regeneration by means of messenger RNA (mRNA) delivery of a cartilage-anabolic runt-related transcription factor 1 (RUNX1). Raman spectroscopy is shown to substantiate at the molecular scale the therapeutic effect of the Runx1 mRNA cartilage regeneration approach. This study demonstrates how the Raman spectroscopic method could support and accelerate the development of new therapies for cartilage diseases.

Avascular necrosis (AVN) involves ischemic cell death of the bone. AVN leaves an abundance of necrotic lipids and debris in the bone marrow, which instigates inflammatory bone repair. Consequently, the necrotic bone microenvironment stimulates excessive bone resorption, leading to joint deformities and osteoarthritis. Here, we performed a detergent-assisted bone wash using poloxamer 407 (P407) to clean the necrotic bone environment by removing lipids and necrotic debris. The new concept was tested using an established ex vivo AVN model of porcine cadaver humeral heads. The P407 wash was performed using P407 solution and followed with saline via two intraosseous needles. Visual inspection and image analyses of average pixel light intensity showed that the P407 wash produced a better-cleaned bone than the saline wash. Analyses of the collected bone wash solution showed a two-fold increase in triglycerides (101 vs. 53 mmol/head, p = 0.006) and a 10-fold increase in the dry weight of the removed debris (1.34 vs. 0.13 g/head, p = 0.02) with the P407 wash compared to saline. The histological evaluation showed significantly decreased Oil-Red-O (fats) staining in the P407-washed bone compared with the saline-washed bone. The in vitro assays of Alizarin red and qPCR showed the P407 wash neither altered the osteogenic behaviors of porcine bone marrow-derived mesenchymal cells (pBMMCs) nor raised inflammatory responses of porcine bone marrow-derived macrophages (pBMMs). In conclusion, detergent-assisted bone wash using P407 produced a better removal of nonsoluble debris from the bone marrow space than the saline wash without causing changes to osteogenesis or inflammatory reactions.

Geopolymers are commonly used in a wide range of applications including binders into the building industry, production of refractory elements, filtration systems, low CO 2 emission applications, etc. Their production can be performed either by acidic or alkaline formulation. In the last 15 years, however, they have been proposed also in biomedical applications for bone tissue regeneration. The aim of this work is the preparation of a thin and homogeneous geopolymer coating on a Ti6Al4V alloy in order to test their futuristic application as coating of prosthetic devices made with this metal alloy. Multilayered coatings were therefore produced by mean of dip coating with the aim of verifying which formulation, acidic or alkaline maximize adhesion. The morphological and chemical characteristics of the coatings were analyzed and adhesion of geopolymers to the substrate was investigated by scratch tests. Finally, a bacterial growth test was performed to verify antibacterial properties of the coatings. Graphical abstract

In this study, we monitored the effect of Al3+ ions on mesenchymal cells (KUSA-A1) and human fibroblasts (NHDF) by means of in vitro experiments by culturing the cells with addition of small concentrations of aluminum ions (i.e. , 0.1, 1, 10, and 100 ppm). Bone formation test was then conducted using KUSA-A1. Small concentrations of aluminum ions delayed but did not completely inhibit cell proliferation. The amount of bone tissue decreased as the concentration of Al3+ increased and crystallinity changes were also detected by Raman spectroscopic experiments. Moreover, Al3+ ions greatly affected both structure and chemistry of bone tissues with mineral nodules becoming larger and atomic substitution of Ca with Al in bone tissue being more preponderant with increasing Al3+ concentration. Such effects in turn impaired the balance between mineral and collagen in the formed bone tissue.

The extent to which sodium levels may be regulated by consumption was examined in two experiments that offered rats foods varying in sodium chloride (NaCl) content. In the first, rats received single purified diets containing from 0% to 3% NaCl. There were no effects of NaCl level on the amount or pattern of daily food intake; water intake, however, increased with salt content. In the second study, rats had choices between a NaCl-free food and a food containing either 1, 2 or 3% NaCl for 1 week each. Total food intake was unaffected. Proportional intake of the salt-free option increased with the salt content of the alternate food, but not sufficiently to maintain a constant NaCl intake. After 8 weeks of exposure to a single food, intake of the salty option increased in the choice tests, but the level of NaCl (from 0.5 to 3.0%) in the exposure-phase food did not affect the subsequent choice. We conclude that when only one food is available, salt intake is governed by caloric requirements and sodium levels are regulated by excretion. When foods differing in NaCl content are available, consumption does contribute to the regulation of sodium balance, but the amount consumed is not tightly controlled. Rats' salt preference appears to increase with age or with experience eating the purified foods offered here, but experience eating salty food does not affect the preferred level of salt.

Surface inactivation of human microbial pathogens has a long history. The Smith Papyrus (2600 ~ 2200 B.C.) described the use of copper surfaces to sterilize chest wounds and drinking water. Brass and bronze on doorknobs can discourage microbial spread in hospitals, and metal-base surface coatings are used in hygiene-sensitive environments, both as inactivators and modulators of cellular immunity. A limitation of these approaches is that the reactive oxygen radicals (ROS) generated at metal surfaces also damage human cells by oxidizing their proteins and lipids. Silicon nitride (Si3N4) is a non-oxide ceramic compound with known surface bacterial resistance. We show here that off-stoichiometric reactions at Si3N4 surfaces are also capable of inactivating different types of single-stranded RNA (ssRNA) viruses independent of whether their structure presents an envelop or not. The antiviral property of Si3N4 derives from a hydrolysis reaction at its surface and the subsequent formation of reactive nitrogen species (RNS) in doses that could be metabolized by mammalian cells but are lethal to pathogens. Real-time reverse transcription (RT)-polymerase chain reaction (PCR) tests of viral RNA and in situ Raman spectroscopy suggested that the products of Si3N4 hydrolysis directly react with viral proteins and RNA. Si3N4 may have a role in controlling human epidemics related to ssRNA mutant viruses.