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Intravascular biosensors have become a crucial and novel class of devices in healthcare, enabling the constant real-time monitoring of essential physiological parameters directly within the circulatory system. Recent developments in micro- and nanotechnology have relevantly improved the sensitivity, miniaturization, and biocompatibility of these devices, thereby enabling their application in precision medicine. This review summarizes the latest advances in intravascular biosensor technologies, with a special focus on glucose and oxygen level monitoring, blood pressure and heart rate assessment, and early disease diagnostics, as well as modern approaches to drug therapy monitoring and delivery systems. Key challenges such as long-term biostability, signal accuracy, and regulatory approval processes are critical considerations. Innovative strategies, including biodegradable implants, nanomaterial-functionalized surfaces, and integration with artificial intelligence, are regarded as promising avenues to overcome current limitations. This review provides a comprehensive roadmap for upcoming research and the clinical translation of advanced intravascular biosensors with a strong emphasis on their transformative impact on personalized healthcare.

Irreversible climate change, including atmosphere temperature extremes, is one of the most important issues of the present time. In this context, the construction industry requires solutions for increasing the energy efficiency of buildings through feedback between temperature adjustment inside buildings and better isolation of the external parts of buildings. Newly developed thermal insulation materials play an important role in this strategy. This paper presents the foamed geopolymer based on metakaolin that can be used as a modern facade material. In order to further improve its thermal insulation properties, the composition of geopolymer was modified with organic substances, i.e., perlite and cellulose fibers (30% and 50% of the volume). The thermal conductivity and insulation properties, density, mineral phases, absorbability, and compressive strength were improved for composite materials. It has been shown that the final properties of the foamed geopolymer can be controlled to a great extent by modifications, and the final properties determine its applicability.

Massive amounts of deposited coal gangue derived from the mining industry constitute a crucial problem that must be solved. On the other hand, common knowledge about the recycling of glass products and the reuse of waste glass is still insufficient, which in turn causes economic and environmental problems. Therefore, this work investigated lightweight geopolymer foams manufactured based on coal gangue, metakaolin, and a mix of them to evaluate the influence of such waste on the geopolymer matrix. In addition, the effect of 20% (wt.) of waste glass on the foams was determined. Mineralogical and chemical composition, thermal behaviour, thermal conductivity, compressive strength, morphology, and density of foams were investigated. Furthermore, the structure of the geopolymers was examined in detail, including pore and structure thickness, homogeneity, degree of anisotropy, porosity with division for closed and open pores, as well as distribution of additives and pores using micro-computed tomography (microCT). The results show that the incorporation of waste glass increased compressive strength by approximately 54% and 9% in the case of coal-gangue-based and metakaolin-based samples, respectively. The porosity of samples ranged from 67.3% to 58.7%, in which closed pores constituted 0.3–1.8%. Samples had homogeneous distributions of pores and additions. Furthermore, the thermal conductivity ranged from 0.080 W/(m·K) to 0.117 W/(m·K), whereas the degree of anisotropy was 0.126–0.187, indicating that the structure of foams was approximate to isotropic.

Nowadays, humanity has to face the problem of constantly increasing amounts of waste, which cause not only environmental pollution but also poses a critical danger to human health. Moreover, the growth of landfill sites involves high costs of establishment, development, and maintenance. Glass is one of the materials whose recycling ratio is still insufficient. Therefore, in the presented work, the influence of the particle size and share of waste glass on the consistency, morphology, specific surface area, water absorption, setting time, and mechanical properties of geopolymers was determined. Furthermore, for the first time, the fire resistance and final setting time of such geopolymer composites were presented in a wide range. Based on the obtained results, it was found that the geopolymer containing 20% unsorted waste glass obtained a final setting time that was 44% less than the sample not containing waste glass, 51.5 MPa of compressive strength (135.2% higher than the reference sample), and 13.5 MPa of residual compressive strength after the fire resistance test (164.7% more than the reference sample). Furthermore, it was found that the final setting time and the total pore volume closely depended on the additive’s share and particle size. In addition, the use of waste glass characterized by larger particle sizes led to higher strength and lower mass loss after exposure to high temperatures compared to the composite containing smaller ones. The results presented in this work allow not only for reducing the costs and negative impact on the environment associated with landfilling but also for developing a simple, low-cost method of producing a modern geopolymer composite with beneficial properties for the construction industry.

Additive manufacturing using cement has evolved rapidly in recent decades, revolutionizing the construction industry. This technology automates building structures through computer-aided design, offering benefits such as reduced material waste, optimized material distribution, and the ability to use composite materials. This paper aims to examine the potential of using copper-slag-based geopolymers in 3D printing. Geopolymers have gained popularity as an alternative and more energy-efficient material to traditional building materials, while copper slag allows for reducing and managing mining industry waste. Moreover, samples formed in molds based on the same material were produced to evaluate the method of manufacturing on the mechanical properties of geopolymers. This paper presents an evaluation of the mechanical properties including the compressive, flexural, and shear strength of the layered material. It reveals promising results, with strength development mainly observed within the first 14 days. The results show that the compressive strength after 28 days of curing is 46.4 MP and 42.1 MPa for formed and printed samples, respectively. Furthermore, the average bending strength value ranges between 7.4 MPa and 7.8 MPa, regardless of the bending direction and forming method. The obtained results show that printed geopolymers demonstrate adequate layer bonding, confirming the profitability of the 3D printing technology. This research confirms that 3D printing technology enables the use of geopolymer binder materials based on copper slag, which opens the door to sustainable alternatives in construction practices.

In recent years, 3D concrete printing technology has been developing dynamically. Intensive research is still being carried out on the composition of the materials dedicated to innovative 3D printing solutions. Here, for the first time, concrete-geopolymer hybrids produced with 3D printing technology and dedicated environmentally friendly building construction are presented. The concrete-geopolymer hybrids consisting of 95% concrete and 5% geopolymer based on fly ash or metakaolin were compared to standard concrete. Moreover, 3D printed samples were compared with the samples of the same composition but prepared by the conventional method of casting into molds. The phase composition, water leachability, compressive, and flexural strength in the parallel and perpendicular directions to the printing direction, and fire resistance followed by compressive strength were evaluated. Concrete-geopolymer hybrids were shown to contain a lower content of hazardous compounds in leaches than concrete samples. The concentration of toxic metals did not exceed the limit values indicated in the Council Decision 2003/33/EC; therefore, the materials were classified as environmentally neutral. The different forms of Si/Al in fly ash and metakaolin resulted in the various potentials for geopolymerization processes, and finally influenced the densification of the hybrids and the potential for immobilization of toxic elements. Although the compressive strength of concrete was approximately 40% higher for cast samples than for 3D printed ones, for the hybrids, the trend was the opposite. The addition of fly ash to concrete resulted in a 20% higher compressive strength compared to an analogous hybrid containing the addition of metakaolin. The compressive strength was 7–10% higher provided the samples were tested in the parallel direction to the Z-axis of the printout. The sample compressive strength of 24–43 MPa decreased to 8–19 MPa after the fire resistance tests as a result of moisture evaporation, weight loss, thermal deformation, and crack development. Importantly, the residual compressive strength of the hybrid samples was 1.5- to 2- fold higher than the concrete samples. Therefore, it can be concluded that the addition of geopolymer to the concrete improved the fire resistance of the samples.

The aim of the article is to analyze the structure and mechanical properties in terms of the cracking mechanics of geopolymer composites based on fly ash and river sand, as well as metakaolin and river sand with three types of reinforcement material: glass fiber, carbon fiber, and aramid fiber, in terms of their use in additive manufacturing. Geopolymer composites were reinforced with fibers in a volume ratio of 0.5%, 1.0%, and 2.0%. Subsequently, these samples were subjected to bending strength tests in accordance with the European standard EN 12390-3. The addition of fibers significantly improved the bending strength of all composites made of metakaolin and sand. The reinforcement with aramid fiber in the amount of 2.0% resulted in more than a 3-fold increase in strength compared to the reinforcement-free composites. An analysis of the morphology of the fibers was carried out on the basis of photos taken from an electron microscope. The correct addition of fibers changes the nature of the fracture from brittle to more ductile and reduces the number of cracks in the material.

Nowadays, one very dynamic development of 3D printing technology is required in the construction industry. However, the full implementation of this technology requires the optimization of the entire process, starting from the design of printing ideas, and ending with the development and implementation of new materials. The article presents, for the first time, the development of hybrid materials based on a geopolymer or ordinary Portland cement matrix that can be used for various 3D concrete-printing methods. Raw materials used in the research were defined by particle size distribution, specific surface area, morphology by scanning electron microscopy, X-ray diffraction, thermal analysis, radioactivity tests, X-ray fluorescence, Fourier transform infrared spectroscopy and leaching. The geopolymers, concrete, and hybrid samples were described according to compressive strength, flexural strength, and abrasion resistance. The study also evaluates the influence of the liquid-to-solid ratio on the properties of geopolymers, based on fly ash (FA) and metakaolin (MK). Printing tests of the analyzed mixtures were also carried out and their suitability for various applications related to 3D printing technology was assessed. Geopolymers and hybrids based on a geopolymer matrix with the addition of 5% cement resulted in the final materials behaving similarly to a non-Newtonian fluid. Without additional treatments, this type of material can be successfully used to fill the molds. The hybrid materials based on cement with a 5% addition of geopolymer, based on both FA and MK, enabled precise detail printing.

We have calculated that with the world population projected to increase from 7.5 billion in 2017 to 9.8 in 2050, the next generation (within 33 years) will produce 12,000–13,000 Mt of plastic, and that the yearly consumption will reach 37–40 kilos of plastic per person worldwide. One of the branches of the plastics industry is the production of plastics for agriculture e.g., seed trays and pots. In this paper, novel metakaolin-based geopolymer composites reinforced with cellulosic fibres are presented as an alternative to plastic pots. Materials can be dedicated to agricultural applications, provided they have neutral properties, however, geopolymer paste and its final products have high pH. Therefore, a two-step protocol of neutralisation of the geopolymer foam pots was optimised and implemented. The strength of the geopolymer samples was lower when foams were neutralised. The reinforcement of geopolymers with cellulose clearly prevented the reduction of mechanical properties after neutralisation, which was correlated with the lower volume of pores in the foam and with the cellulose chemical properties. Both, neutralisation and reinforcement with cellulose can also eliminate an efflorescence. Significantly increased plant growth was found in geopolymer pots in comparison to plastic pots. The cellulose in geopolymers resulted in better adsorption and slower desorption of minerals during fertilisation. This effect could also be associated with a lower number of large pores in the presence of cellulose fibres in pots, and thus more stable pore filling and better protection of internal surface interactions.

The aim of this study was to develop and characterize UV-crosslinked hydrogel matrices based on polyethylene glycol diacrylate (PEGDA), gum arabic, betaine, and sodium alginate for potential bioanalytical applications. Various physicochemical analyses were performed, including pre-polymerization emulsion stability (Multiscan), FT-IR spectroscopy, swelling behavior in physiological buffers, pH monitoring, contact angle measurements, and morphological assessment via SEM and optical microscopy. The results demonstrated that both alginate content and UV exposure time significantly influence the structural and functional properties of the hydrogels. The highest swelling ratio (2.32 g/g) was observed for the formulation containing 5% sodium alginate polymerized for 5 min (5SA_5), though this sample showed mechanical fragmentation during incubation. In contrast, the most balanced performance was achieved for the 10SA_15 formulation, which maintained structural integrity and exhibited a swelling ratio of 1.92 g/g after 9 days. The contact angle analysis revealed a surface hydrophilicity range from 50° to 100°, with the lowest angle (50°) recorded for 10SA_5, indicating high surface wettability. These findings confirm the suitability of such hydrogels for biomedical applications, particularly as absorbent, stable platforms for drug delivery or wound healing.