Development Of Alternative Materials Research Articles

Role of Non-Mesh Grafts in Surgical Treatment of Stress Urinary Incontinence

Stress urinary incontinence refers to a multifactorial disease characterized by involuntary urination associated with a sudden increase in intra­abdominal pressure. Millions of females around the world suffer from stress incontinence each year. Conservative methods of treatment and physical rehabilitation are considered to be ineffective, thereby driving the need for surgical treatment. Sling surgeries comprise a widely used surgical technique for the treatment of stress urinary incontinence due to their affordability and minimal time investment. Introduction of synthetic polypropylene mesh prostheses in the treatment of stress incontinence made them the most common material. However, the accumulated experience and complications associated with the use of mesh grafts contribute to the recent decline in the popularity of synthetic slings and give rise to the search for and development of alternative materials for the surgical treatment of stress urinary incontinence. Since the need for treatment of urinary incontinence remains high, fascia autograft surgeries have been proposed, even though they require an additional surgical procedure and expose the patient to complications at the donor site of the graft. In addition, surgeons use allografts and xenografts, and regenerative technology is developing in this field. Considering high social significance of this problem, the present paper is aimed at reviewing the scientific literature concerning grafts for the treatment of stress incontinence.

Gamma radiation attenuation, mechanical properties and microstructure of barite-modified cement and geopolymer mortars

The present study contributes to the development of alternative materials for radiation shielding, focusing on environmental sustainability and material cost efficiency. The primary aim was to evaluate the compressive and flexural strength, mineral composition, microstructure, and gamma-ray attenuation properties of cement mortars and geopolymer mortars containing barite powder. Mortars based on ordinary Portland cement (OPC) and fly ash geopolymers with varying amounts of barite powder were assessed for their shielding properties at energy levels associated with the decay of 137Cs. From the results, key parameters such as the linear attenuation coefficient (μ), mass attenuation coefficient (μm), half-value layer (HVL), and tenth-value layer (TVL) were determined. The results showed that while cement-based composites exhibited superior gamma radiation attenuation compared to fly ash geopolymer mortars, the latter had higher mass attenuation efficiency, meaning less material density was required for the same level of shielding. Additionally, cement mortars had 23–25 % higher mechanical strength than geopolymer mortars. Importantly, the inclusion of barite powder improved the radiation shielding performance of both materials by 7–10 %, demonstrating its effectiveness in enhancing the protective properties of these mortars. This research highlights the potential of fly ash geopolymer mortars as viable, eco-friendly alternatives to traditional cement mortars in radiation shielding applications.

Development of Biocompatible Coatings with PVA/Gelatin Hydrogel Films on Vancomycin-Loaded Titania Nanotubes for Controllable Drug Release.

This study investigates the utilization of poly(vinyl alcohol) (PVA)/gelatin hydrogel films cross-linked with glutaraldehyde as a novel material to coat the surface of vancomycin-loaded titania nanotubes (TNTs), with a focus on enhancing biocompatibility and achieving controlled vancomycin release. Hydrogel films have emerged as promising candidates in tissue engineering and drug-delivery systems due to their versatile properties. The development of these hydrogel films involved varying the proportions of PVA, gelatin, and glutaraldehyde to achieve the desired properties, including the gel fraction, swelling behavior, biocompatibility, and biodegradation. Among the formulations tested, the hydrogel with a PVA-to-gelatin ratio of 25:75 and 0.2% glutaraldehyde was selected to coat vancomycin-loaded TNTs. The coated TNTs demonstrated slower release of vancomycin compared with the uncoated TNTs. In addition, the coated TNTs demonstrated the ability to promote osteogenesis, as evidenced by increased alkaline phosphatase activity and calcium accumulation. The vancomycin-loaded TNTs coated with hydrogel film demonstrated effectiveness against both E. coli and S. aureus. These findings highlight the potential benefits and therapeutic applications of using hydrogel films to coat implant materials, offering efficient drug delivery and controlled release. This study contributes valuable insights into the development of alternative materials for medical applications, thereby advancing the field of biomaterials and drug delivery systems.

Accelerated Discovery of Multi-Metallic Nanostructured Catalysts for Anion Exchange Membrane Water Electrolyzers: Oxygen Evolution Reaction

The current reliance on platinum group metals (PGMs) as electrocatalysts for the oxygen evolution reaction (OER) in proton exchange membrane (PEM) water electrolyzers, the current industry standard, presents a significant barrier to the widespread adoption of hydrogen as a clean energy carrier. The scarcity and high cost of PGMs necessitate the development of alternative materials and technologies that offer comparable performance at a reduced cost. In this context, anion exchange membrane (AEM) water electrolyzers have emerged as a promising alternative.This presentation addresses this imperative by focusing on the design and synthesis of nanostructured mesoporous multi-metallic catalysts for AEM water electrolyzers, leveraging earth-abundant materials as alternatives to the rare and expensive PGMs currently employed in PEM water electrolyzers. Transition metal oxides, sulfides, and phosphides are promising candidates to replace PGMs, given their abundance, low cost, and tunable catalytic properties conducive to high OER activity. The OER activity and durability of newly developed multi-metallic transition metal catalysts in an alkaline environment will be discussed in this presentation.Preliminary results demonstrate that the developed catalysts exhibit high OER activity, achieving a potential of <1.5 V versus RHE at a current density of 10 mA cm⁻² in 1.0 M KOH. Notably, this surpasses the performance of commercial OER catalysts in alkaline environments. Furthermore, the catalyst exhibits superior durability, with < 0.5 mV/h potential loss over 100 h durability test at 10 mA cm⁻² in 1.0 M KOH.AcknowledgmentsThis work was supported by the U.S. Department of Energy (DOE), Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office (HFTO) under the auspices of the Electrocatalysis Consortium (ElectroCat 2.0). Argonne is managed for the U.S Department of Energy by the University of Chicago Argonne, LLC, under Contract DE-AC-02-06CH11357 .

A Density Functional Theory Study of the Physico-Chemical Properties of Alkali Metal Titanate Perovskites for Solar Cell Applications.

The urgent need to shift from non-renewable to renewable energy sources has caused widespread interest in photovoltaic technologies that allow us to harness readily available and sustainable solar energy. In the past decade, polymer solar cells (PSCs) and perovskite solar cells (Per-SCs) have gained attention owing to their low price and easy fabrication process. Charge transport layers (CTLs), transparent conductive electrodes (TCEs), and metallic top electrodes are important constituents of PSCs and Per-SCs, which affect the efficiency and stability of these cells. Owing to the disadvantages of current materials, including instability and high cost, the development of alternative materials has attracted significant attention. Owing to their more flexible physical and chemical characteristics, ternary oxides are considered to be appealing alternatives, where ATiO3 materials-a class of ternary perovskite oxides-have demonstrated considerable potential for applications in solar cells. Here, we have employed calculations based on the density functional theory to study the structural, optoelectronic, and magnetic properties of ATiO3 (A=Li, Na, K, Rb, and Cs) in different crystallographic phases to determine their potential as PSCs and Per-SCs materials. We have also determined thermal and elastic properties to evaluate their mechanical and thermal stability. Our calculations have revealed that KTiO3 and RbTiO3 possess similar electronic properties as half-metallic materials, while LiTiO3 and CsTiO3 are metallic. Semiconductor behavior with a direct band gap of 2.77 eV was observed for NaTiO3, and calculations of the optical and electronic properties predicted that NaTiO3 is the most appropriate candidate to be employed as a charge transfer layer (CTL) and bottom transparent conducting electrode (TCE) in PSCs and Per-SCs, owing to its transparency and large bandgap, whereas NaTiO3 also provided superior elastic and thermal properties. Among the metallic and half-metallic ATiO3 compounds, CsTiO3 and KTiO3 exhibited the most appropriate features for the top electrode and additional absorbent in the active layer, respectively, to enhance the performance and stability of these cells.

RETRACTED: Engineering a high-performance W-doped Sr0.9Fe0.67Ti0.3Co0.03O3-δ hydrogen electrode for Solid Oxide Electrolysis Cells (SOECs)

Traditionally, Ni-based cermet fuel electrodes have been extensively utilized in Solid Oxide Electrolysis Cells (SOECs) for their excellent conductivity and catalytic properties. However, the development of alternative materials has gained attraction due to concerns over Ni's susceptibility to carbon deposition and long-term stability issues. To overcome this issue, we designed Sr0.9Fe0.67Ti0.30Co0.07O3-δ (SFTC) and W-doped SFTC (SFTCW) via the sol-gel method and thoroughly characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TG-DSC), and electrochemical tests. The results reveal that the incorporation of W enhances the stability of the electrode material under both oxidizing and reducing conditions, with no impurity phases detected. Furthermore, W doping promotes the precipitation of Co–Fe alloy, preserves the original structure, and facilitates the creation of oxygen vacancies within the material. In a reducing atmosphere containing 40 % H2O, SFTCW demonstrates superior electrolysis performance at an electrolysis voltage of 1.8 V, exhibiting a remarkable improvement of approx. 35 % compared to the SFTC sample. During a 100 h long-term stability test, the current density of SFTCW increased from -240 mA cm–2 to -270 mA cm–2, attributed to the enhanced hydrogen oxidation activity and increased reactive sites resulting from W doping, thereby enhancing its long-term stability. This work provides a feasible scheme for the selection and construction of hydrogen electrodes for electrolytic water.

Advancing Detectivity and Stability of Near-Infrared Organic Photodetectors via a Facile and Efficient Cathode Interlayer.

Near-infrared (NIR) organic photodetectors (OPDs) are pivotal in numerous technological applications due to their excellent responsivity within the NIR region. Polyethylenimine ethoxylated (PEIE) has conventionally been employed as an electron transport layer (hole-blocking layer) to suppress dark current (JD) and enhance charge transport. However, the limitations of PEIE in chemical stability, processing conditions, environmental impact, and absorption range have spurred the development of alternative materials. In this study, we introduced a novel solution: a hybrid of sol-gel zinc oxide (ZnO) and N,N'-bis(N,N-dimethylpropan-1-amine oxide)perylene-3,4,9,10-tetracarboxylic diimide (PDINO) as the electron transport layer for NIR-OPDs. Our fabricated OPD exhibited significantly improved responsivity, reduced internal traps, and enhanced charge transfer efficiency. The detectivity, spanning from 400 to 1100 nm, surpassed ∼5 × 1012 Jones, reaching ∼1.1 × 1012 Jones at 1000 nm, accompanied by an increased responsivity of 0.47 A/W. Also, the unpackaged OPD remarkedly demonstrated stable JD and external quantum efficiency (EQE) over 1000 h under dark storage conditions. This innovative approach not only addresses the drawbacks of conventional PEIE-based OPDs but also offers promising avenues for the development of high-performance OPDs in the future.

Repercussion of natural silk fibers from spider and silkworms on the mechanical properties of composite materials

Costly synthetic fibers like kevlar, glass, and carbon lead to expensive production costs for products made from these materials, necessitating the development of alternate materials. As a more sustainable and affordable substitute for synthetic reinforcement materials like glass, carbon, and kevlar, natural fiber has gained popularity. Silk fiber obtained from spiders and silkworms is one type of natural fiber that has excellent mechanical properties such as tensile strength, tensile modulus, and breaking elongation. Its mechanical and biocompatibility characteristics are unmatched by those of other synthetic and natural fibers. This article discusses various silk fiber-related topics such as chemical composition, mechanical properties, and applications with respect to spiders and silkworms. Also, the requirement for silk fiber to be used as a reinforcement in composite materials is highlighted. Furthermore, the mechanical properties of silk fiber-reinforced composites (SFRCs) are also explored in this review. It is acceptable to draw the conclusion that the use of SFRCs in the creation of useful and possibly lucrative applications as novel materials in many industrial areas is inevitable.

Assessing the environmental and health impacts of plastic production and recycling

Plastic production and recycling have become integral processes in modern society, but their environmental and health impacts have garnered significant attention in recent years. This review outlines key findings from a comprehensive assessment of these impacts, drawing from a range of scientific literature and empirical studies. The environmental footprint of plastic production encompasses various stages, from extraction of raw materials to manufacturing and distribution. These processes contribute to greenhouse gas emissions, energy consumption, and pollution of air, water, and soil. Additionally, plastic waste, particularly single-use items, poses a significant threat to ecosystems and wildlife, with marine environments being particularly vulnerable. While recycling is often promoted as a solution to mitigate the environmental impact of plastics, its effectiveness is limited by various factors. Challenges such as contamination, inadequate infrastructure, and low rates of collection and recycling hinder the potential benefits. Moreover, the recycling process itself can generate pollutants and emissions, albeit to a lesser extent than primary production. Beyond environmental concerns, the health implications of plastic use are increasingly recognized. Plastics contain additives such as phthalates and bisphenols, which have been linked to endocrine disruption, reproductive issues, and other health problems in humans and wildlife. Furthermore, the accumulation of microplastics in the environment raises concerns about potential bioaccumulation and transfer through the food chain, with implications for human health. Addressing the environmental and health impacts of plastic production and recycling requires a multifaceted approach, including reduction of plastic consumption, improvement of recycling infrastructure and technologies, development of alternative materials, and policy interventions to promote sustainable practices. This assessment highlights the complex interplay between plastic usage, environmental degradation, and public health, underscoring the need for concerted efforts to mitigate these challenges.

Development of ternary polymeric films based on cassava starch, pea flour and green banana flour for food packaging

The development of alternative materials to replace plastics used in food packaging is an important approach to reducing environmental pollution and minimizing harmful impacts on ecosystems. In this study, biopolymeric films were formulated using cassava starch (Manihot esculenta Crantz), pea flour (Pisum sativum) and green banana flour (Musa sp.) to obtain a material for application in food packaging. The influence of a plasticizer on the optical and physicochemical properties of the films was analyzed and the synergy between higher concentrations of starch and plasticizer resulted in films with low opacity. In addition, the morphology, thermal, mechanical and barrier properties were examined. The film with the best formulation (p < 0.05) contained 12 g cassava starch, 3.6 g pea flour and 30 % glycerol (the maximum levels of the experiment). This film presented average values of thickness, moisture, solubility, opacity, maximum strength (F), maximum tensile stress (σ), elongation at break (ε) and elasticity (E) of 0.47 mm, 19.95 %, 87.45 %, 20.93 %, 9.30 N, 1.75 MPa, 30.10 % and 5.93 %, respectively. This research demonstrates the potential application of films obtained by combining starches from different sources. The sustainable production of environmentally-friendly packaging provides an alternative to fossil-based plastics, which have well-documented adverse effects on the environment.

Optimization of the physical properties of recycled plastic hybrid composites reinforced with rubberwood flour and crab shell flour for underwater use

This research aimed to optimize the composition and physical properties of recycled high-density polyethylene (rHDPE) hybrid composites reinforced with rubberwood flour (RWF) and crab shell flour (CS) for application in water immersion. The effects of composition and deterioration in physical properties after immersion in different water conditions (distilled water and seawater) were investigated. D-optimal mixture experimental design and response surface methodology were applied. The findings showed that all the physical properties deteriorated with an increase in immersion times. The increasing addition of CS increased the density, water absorption, thickness swelling, and surface roughness of the samples before and after being immersed in distilled water and seawater. Further, the results revealed that the optimal composition for application in water immersion included 60.0 wt% rHDPE, 29.5 wt% RWF, 5.6 wt% CS, 3.5 wt% maleic anhydride-grafted polyethylene, 0.5 wt% ultraviolet stabilizers, and 1.0 wt% lubricant with a desirability score value of 95.80 %. The predicted response of density, color measurement, surface roughness, water absorption, and thickness swelling were 0.89 g/cm3, 10.11, 4.59 µm, 10.27 %, and 7.73 %, respectively. Based on the findings in this research, the effective application of naturally sourced additives in composite products, and using the optimized rHDPE, RWF, and CS contents would enable the development of alternative materials for applications in water immersion.

Perovskite-Based Materials As Alternative Fuel Electrodes for Solid Oxide Electrolysis Cells (SOECs)

Enhancing the lifetime of SOECs is a challenge to overcome regarding their commercialization. A major impact on the lifetime of a cell during electrolysis operation, particularly under thermoneutral potential and high current densities, is the degradation of the currently used electrode materials, mainly the Ni-based fuel electrode. Among other things, nickel migration, as well as agglomeration, is leading to a significant performance loss after a certain operating time. Hence, preventing degradation mechanisms of the fuel electrode during operation is a necessity to be tackled for using it commercially. Therefore the development of alternative materials which combine sufficient performance with the lowest possible degradation rate is needed. Perovskite-based materials have been investigated in the last years as all-ceramic possible substitutes.In this work, four perovskites (i.e., strontium-iron-niobate double perovskite (SFN), a strontium-iron-titanate material (STF), a lanthanum-strontium-titanate (LST) and a lanthanum-strontium-iron-manganese (LSFM)) were examined as alternative electrode materials. The aim is to substitute the active fuel electrode, at the moment commonly consisting of Ni cermets, with a perovskite-based electrode while at the same time using state-of-the-art materials for the remaining cell components.The first task here was to look at the chemical stability between the new electrode material and the electrolyte under the standard conditions used to manufacture fuel electrode-supported SOECs.Therefore, the compatibility between these perovskites with a yttria-stabilized-zirconia (8YSZ) electrolyte and how nickel inside the fuel electrode affected the chemical stability during sintering in air at 1400 °C for 5 h was investigated. At this point, SFN double perovskite shows the lowest interaction between the electrode and electrolyte after thermal treatment.A thorough evaluation of all preliminary tests (including compatibility, stability in reducing atmospheres and redox stability tests) indicates that SFN shows so far the best results of the four materials in terms of application as fuel electrode material, followed directly by STF.Thus SFN and STF were chosen to be evaluated in single cell tests. The tests of pure SFN and STF electrodes are carried out with electrolyte-supported single cells exhibiting an LSCF air electrode and symmetrical cells, respectively. CV-characteristics and impedance spectra are measured at varied operating conditions. Impedance spectra are evaluated by the distribution of relaxation times (DRT). These examinations are carried out to give an insight into the electrochemical properties of pure perovskite-based fuel electrodes in order to obtain a base for further optimization.

Antibacterial effect and cell metabolic activity of Na2CaSi2O6, β-NaCaPO4, and β-NaCaPO4-SiO2versus hydroxyapatite

Hydroxyapatite (Ca5(PO2)3(OH)) is extensively used in diverse clinical applications because of its relatively simple synthesis protocol, low cost, and chemical similarity to the mineral component of bones and teeth. Some limitations regarding bioactivity and antibacterial activity have motivated changes in its structure and the development of alternative materials to achieve better performances as bioceramics. In this study, the antibacterial effect and cell metabolic activity of the main crystalline phases (Na2CaSi2O6, β-NaCaPO4, and β-NaCaPO4−SiO2) derived from the original 45S5 bioactive glass were evaluated and compared with those induced by a commercial powder of hydroxyapatite. Powder samples of Na2CaSi2O6, β-NaCaPO4, and β-NaCaPO4−SiO2 were synthesized by a simple and reproducible solid-state reaction method. The β-NaCaPO4−SiO2 sample exhibited the strongest effect against Pseudomonas aeruginosa, Staphylococcus aureus, and S. epidermidis, which are bacteria that normally colonize the skin but can become opportunistic pathogens when the host's resistance is low. All bacteria were eliminated within 5 min in the direct-contact test, an effect that is likely associated with changes in pH in the microenvironment generated from the partial solubilization of the material and the action of certain released ions, such as Ca2+. In vitro experiments with human cells, no sample showed cytotoxicity, and the β-NaCaPO4−SiO2 sample stood out once more inducing the most positive effect on keratinocyte and stem cell viability. Overall, the tested materials demonstrated similar or better (β-NaCaPO4−SiO2) biochemical properties than hydroxyapatite. This finding encourages us, and perhaps other research groups, to assess the bio-performance of these materials more comprehensively, aiming at the development of new products for use in tissue engineering.

A novel low carbon cementitious binder incorporating yellow sand and clinker for non-structural application

Concrete preparation requires a significant quantity of natural reserves worldwide and necessitates the development of alternative materials and sources. The manufacturing of concrete needs around 27 billion tonnes of raw material inventory, representing four tonnes of concrete per person per year. By 2025, around 4 billion tonnes of carbon dioxide (approximately) are estimated to be released to the atmosphere during cement production. This study focuses on the development of a novel Low Carbon Cementitious Binder (LCCB) for non-structural applications, The LCCB developed in this study is a mortar that incorporates natural sand as an aggregate. The composition of the LCCB is 60% linker, 30% clinker, 10% lime, and natural sand. The natural sand is used as an aggregate in the mortar, which contributes to its overall strength and durability. The compressive strength of the LCCB was tested after 15 years, and the results showed a strength of 27 MPa, indicating its potential for use in construction. Additionally, the phase formation of the LCCB was confirmed using XRD, and SEM analysis, and its mineralogy was evaluated using microscopy. The results indicated that the LCCB is a suitable alternative to cement-based binders for non-structural applications, offering significant benefits in terms of reduced environmental impact and sustainability. Overall, this study represents a significant step towards developing more sustainable and environmentally friendly materials for the construction industry.

In-Service Performance Evaluation of Flexible Pavement with Lightweight Cellular Concrete Subbase

The objective of engineers to improve the long-term performance of road infrastructure in changing global climate has led to the development of alternate materials for pavement construction. Lightweight cellular concrete (LCC) is a viable option for colder climates where pavements undergo several freeze-thaw cycles each year, resulting in faster deterioration of pavements. This is due to LCCs’ excellent freeze-thaw resistance, ease of placement, and potential sustainability benefits such as reduced use of virgin material and industrial by-products. However, there is a need to quantify these benefits and develop unified specifications for using LCC in the pavement structure. Therefore, this study examined the performance of flexible pavement sections that included a subbase layer, unbound granular materials for the control section, and three LCC densities (400, 475, and 600 kg/m3) for the LCC sections. Post-construction evaluation of pavement stiffness and roughness were evaluated using a Lightweight deflectometer and SurPro equipment. The results showed that LCC subbase thickness ≥ 250 mm produced over 22% smoother riding surfaces than unbound granular pavements while increasing pavement stiffness by up to 21%. Finally, this study recommends that LCC subbase thickness should not be thinner than 250 mm when using densities below 475 kg/m3 over weak subgrades.

Reaction mechanisms in geopolymers produced from sugarcane bagasse ash

The production of Portland cement exhibits significant importance for social and economic development of a country, however also generates environmental impacts from the extraction of raw materials to the production of clinker. Despite the impacts, the demand for Portland cement is still growing in developing countries such as India, China, and Brazil. Faced with this impasse, research for the development of alternative materials to Portland cement is growing around the world. Among these researches, those related to alkali-activated materials (AAMs) stand out. AAMs are considered more sustainable than Portland cement because emit less CO2 during their production process. In addition, the raw materials used in its development are generally wastes from other industrial processes. Sugarcane bagasse ash (SCBA) is an example of residue generated on a large scale in Brazil and with great potential for use in the production of AAMs. Therefore, the present work seeks to develop AAMs using SCBA as an exclusive precursor. For this, the material's viability was verified through physical, mechanical, morphological, and calorimetric tests. As a result, concluded that SCBA is a viable precursor for AAMs, promoting sustainability and innovation in the field of construction materials. In addition, the main mechanism of the reaction of SCBA pastes is the diffusion process, independent of paste formulation and the silicate is crucial for the degree of reaction at early age. At the same time, the compressive strength and microstructure are strongly dependent on alkalis and silicate content and SiO2/Na2O proportions around 1.0 are the optimum point for SCBA pastes.

Development of active and biodegradable film of ternary-based for food application

The effectiveness of plastic packaging in protecting food is quite appreciable, but its non-biodegradable characteristic raises concerns about environmental impacts. This has drawn attention to the development of alternative materials for food packaging from bio-based polymers. Chitosan, a polysaccharide with biodegradable, biocompatible, and non-toxic properties, is widely used in the formulation of food films. The objective of this work was to create a biodegradable and sustainable chitosan-based film whose active and intelligent action is obtained from red cabbage anthocyanins and the addition of propolis. The edible film’s thickness and total polyphenol content were 61.0 ±0.1μm and 20.08 ±0.5 mgAG g-1, respectively. The content of phenolic compounds and the biodegradation showed significant results (p &lt;0.05), besides the good thermal stability to 200 °C and transparency. The proposed formulation developed an edible, biodegradable, and active (antioxidant) film with interesting heat-sealing resistance, moisture barrier and gas transfer, which contributes to increasing food shelf life.

Fast Degradable Calcium Phosphate Cement for Maxillofacial Bone Regeneration.

The aim of this preclinical study was to test the applicability of calcium phosphate cement (CPC)-poly(lactic-co-glycolic acid) (PLGA)-carboxymethylcellulose (CMC) as a bone substitute material for guided bone regeneration (GBR) procedures in a clinically relevant mandibular defect model in minipigs. In the study, a predicate device (i.e., BioOss®) was included for comparison. Critical-sized circular mandibular bone defects were created and filled with either CPC-PLGA-CMC without coverage with a GBR membrane or BioOss covered with a GBR membrane and left to heal for 4 and 12 weeks to obtain temporal insight in material degradation and bone formation. Bone formation increased significantly for both CPC-PLGA-CMC and BioOss with increasing implantation time. Further, no significant differences were found for bone formation at either 4 or 12 weeks between CPC-PLGA-CMC and BioOss. Finally, bone substitute material degradation increased significantly for both CPC-PLGA-CMC and BioOss from 4 to 12 weeks of implantation, showing the highest degradation for CPC-PLGA-CMC (∼85%) compared to BioOss (∼12%). In conclusion, this minipig study showed that CPC-PLGA-CMC can be used as a bone-grafting material and stimulates bone regeneration to a comparable extent as with BioOss particles. Importantly, CPC-PLGA-CMC degrades faster compared to BioOss, is easier to apply into a bone defect, and does not need the use of an additional GBR membrane. Consequently, the data support the further investigation of CPC-PLGA-CMC in human clinical trials. Impact statement Guided bone regeneration (GBR) is a frequently used dental surgical technique to regenerate the alveolar ridge to allow stable implant installation. However, stabilization of the GBR membrane and avoidance of bone graft movement remain a challenge. Consequently, there is need for the development of alternative materials to be used in GBR procedures that are easier to apply and induce predictable bone regeneration. In this minipig study, we focused on the applicability of calcium phosphate cement-poly(lactic-co-glycolic acid)-carboxymethylcellulose as an alternative bone substitute material for GBR procedures without the need of an additional GBR membrane.

Review of Bacterial Nanocellulose-Based Electrochemical Biosensors: Functionalization, Challenges, and Future Perspectives.

Electrochemical biosensing devices are known for their simple operational procedures, low fabrication cost, and suitable real-time detection. Despite these advantages, they have shown some limitations in the immobilization of biochemicals. The development of alternative materials to overcome these drawbacks has attracted significant attention. Nanocellulose-based materials have revealed valuable features due to their capacity for the immobilization of biomolecules, structural flexibility, and biocompatibility. Bacterial nanocellulose (BNC) has gained a promising role as an alternative to antifouling surfaces. To widen its applicability as a biosensing device, BNC may form part of the supports for the immobilization of specific materials. The possibilities of modification methods and in situ and ex situ functionalization enable new BNC properties. With the new insights into nanoscale studies, we expect that many biosensors currently based on plastic, glass, or paper platforms will rely on renewable platforms, especially BNC ones. Moreover, substrates based on BNC seem to have paved the way for the development of sensing platforms with minimally invasive approaches, such as wearable devices, due to their mechanical flexibility and biocompatibility.

Contribution to low-carbon cement studies: Effects of silica fume, fly ash, sugarcane bagasse ash and acai stone ash incorporation in quaternary blended limestone-calcined clay cement concretes

Nearly 10% of global carbon dioxide (CO2) emissions come from Portland cement production, in turn exacerbating the Greenhouse Effect. Consequently, the development of alternative materials to mitigate this adverse environmental impact is essential. Limestone-Calcined Clay Cement (LC³) is presented in academic literature as an alternative for reducing CO2 levels from the cement industry without significant modifications in concrete properties. However, the use of wastes from other industries – known as supplementary cementitious materials (SCMs) – in LC³ mixtures should be investigated due to the interaction between SCMs and calcined clays. This study evaluated the properties of Limestone-Calcined Clay Cement Concretes containing different SCMs, namely silica fume, fly ash, sugarcane bagasse ash and acai stone ash, in fresh and hardened states, as well as its durability. Slump, compressive and splitting tests, carbonation and volumetric electrical resistivity analyses, Thermogravimetric Analysis (TGA), Energy Dispersive X-Ray Spectroscopy (EDS), X-Ray Fluorescence (XRF) and Scanning Electron Microscopy (SEM) images were performed in this study. Results showed that high superplasticizer dosages are required in LC³ in order to obtain workable concretes independent of SCMs presence. A competition between SCMs and calcined clay for the portlandite consumption in pozzolanic reactions was noted, reducing compressive strength between 20% and 45% of LC³ mixtures. TGA analysis showed that all portlandite was consumed, mainly by the pozzolanic reactions from calcined clay. The presence of SCM in LC³ concretes increased the electrical resistivity up to 48%. However, all LC³ concretes presented higher carbonation fronts compared to the reference Portland cement concrete due to the low availability of calcium to react with CO2 that penetrates through concrete pores. Among the SCMs, silica fume, fly ash and sugarcane bagasse ash presented a suitable performance to use in LC³ mixture. However, LC³ silica fume concretes presented the best global performance considering concrete properties in fresh and hardened state, as well as its durability.