878 research outputs found

    Functional Nanomaterials and Polymer Nanocomposites: Current Uses and Potential Applications

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    This book covers a broad range of subjects, from smart nanoparticles and polymer nanocomposite synthesis and the study of their fundamental properties to the fabrication and characterization of devices and emerging technologies with smart nanoparticles and polymer integration

    Smart Gas Sensors: Materials, Technologies, Practical ‎Applications, and Use of Machine Learning – A Review

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    The electronic nose, popularly known as the E-nose, that combines gas sensor arrays (GSAs) with machine learning has gained a strong foothold in gas sensing technology. The E-nose designed to mimic the human olfactory system, is used for the detection and identification of various volatile compounds. The GSAs develop a unique signal fingerprint for each volatile compound to enable pattern recognition using machine learning algorithms. The inexpensive, portable and non-invasive characteristics of the E-nose system have rendered it indispensable within the gas-sensing arena. As a result, E-noses have been widely employed in several applications in the areas of the food industry, health management, disease diagnosis, water and air quality control, and toxic gas leakage detection. This paper reviews the various sensor fabrication technologies of GSAs and highlights the main operational framework of the E-nose system. The paper details vital signal pre-processing techniques of feature extraction, feature selection, in addition to machine learning algorithms such as SVM, kNN, ANN, and Random Forests for determining the type of gas and estimating its concentration in a competitive environment. The paper further explores the potential applications of E-noses for diagnosing diseases, monitoring air quality, assessing the quality of food samples and estimating concentrations of volatile organic compounds (VOCs) in air and in food samples. The review concludes with some challenges faced by E-nose, alternative ways to tackle them and proposes some recommendations as potential future work for further development and design enhancement of E-noses

    Lanthanide-doped upconversion nanoparticles (UCNPs) for biomedical applications

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    This thesis examines the need for new antibacterial materials to treat small colony variants (SCVs) of Staphylococcus (S.) aureus bacteria and their parental strains. While ZnO-based nanoparticles (NPs) activated by ultraviolet (UV) and short wavelength visible light have been researched for their antibacterial properties, the potential benefits of incorporating UCNPs to allow activation by near-infrared (NIR) light have been overlooked. This study aims to fill this research gap by comprehensively investigating the synthesis and performance of ZnO-coated lanthanide-doped upconversion nanoparticle (UCNP) composites activated by NIR light against S. aureus SCVs and parental strains. Furthermore, this research addresses the limited understanding of the potential risks associated with UV emission from UCNPs used as fluorescent probes in super-resolution microscopy (SRM). Despite extensive research on the usage of UCNPs as fluorescent probes for SRMs, the potential cytotoxic effects of UV emission from UCNPs have not been thoroughly studied. To advance cellular imaging techniques and ensure cellular viability, a comprehensive investigation of UV emission from UCNPs is necessary. This thesis aims to identify and quantify UV emission by UCNPs used in SRM and develop strategies to minimise UV emission and mitigate potential cytotoxic effects. These two main aims are addressed in three results chapters. The first aim, the focus of chapters 2 and 3, focuses on the synthesis UCNP@ZnO composites that can be activated by NIR light for antimicrobial photodynamic therapy (aPDT) applications against S. aureus SCVs and parental strains. Chapter 2 reports the synthesis and performance of these composites, showing these materials to be effective antibacterial therapies against S. aureus SCVs, while chapter 3 improves upon the performance of these composites by careful tuning of the UCNP core and provides enhancements to the ZnO shell composition to improve reactive oxygen species generation and add a second mode of action in the form of silver nanoparticles. The second aim of this research is covered in chapter 4, which reports an investigation into the UV emission from UCNPs used as fluorescent probes in SRM. The work posits the need to understand the UV emission properties of these UCNPs as knowledge of these and the potential for cytotoxic effects are crucial for optimizing cellular imaging experiments and ensuring accurate and reliable results. Chapter 4 identifies design features and compositions that can limit UV emission, thereby minimizing the risk of phototoxicity and advancing the field of cellular imaging. Overall, the findings from this research have the potential to contribute to the development of safer and more effective targeted antibacterial therapies and enhance the understanding of UV emissions in cellular imaging techniques.Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering, 202

    Nanotechnology for high-performance textiles: A promising frontier for innovation

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    Nanotechnology embodies a groundbreaking innovation for the textile and apparel industry, facilitating enhancements to the functionality and performance of textiles, including durability, resistance to water, odor, flame, stain, UV-protection, and antimicrobial properties. Nanotechnology also enables biosensing, drug delivery, energy generation, and storage in textiles. Here, we present a comprehensive overview of the possibilities offered by nanotechnology in the context of high-performance textiles providing a roadmap for future research and development in this exciting field. We scrutinize the current research on nanotechnology in textiles, exploring various types of nanomaterials and their properties, the methods of incorporating nanomaterials into textiles, and the numerous applications of high-performance textiles across critical industries such as healthcare, military, sports, fashion, and wearable electronics. We conclude the review with an analysis of the potential health and environmental concerns arising from the use of nanotechnology in textiles, emphasizing the importance of further research in these areas

    Advances in nanomaterials integration in CMOS-based electrochemical sensors: a review

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    The monolithic integration of electrochemical sensors with instrumentation electronics on semiconductor technology is a promising approach to achieve sensor scalability, miniaturization and increased signal to noise ratio. Such an integration requires post-process modification of microchips (or wafers) fabricated in standard semiconductor technology (e.g. CMOS) to develop sensitive and selective sensing electrodes. This review focuses on the post-process fabrication techniques for addition of nanomaterials to the electrode surface, a key component in the construction of electrochemical sensors that has been widely used to achieve surface reactivity and sensitivity. Several CMOS-compatible techniques are summarized and discussed in this review for the deposition of nanomaterials such as gold, platinum, carbon nanotubes, polymers and metal oxide/nitride nanoparticles. These techniques include electroless deposition, electro-chemical deposition, lift-off, micro-spotting, dip-pen lithography, physical adsorption, self-assembly and hydrothermal methods. Finally, the review is concluded and summarized by stating the advantages and disadvantages of these deposition methods

    Biomaterials for Bone Tissue Engineering 2020

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    This book presents recent advances in the field of bone tissue engineering, including molecular insights, innovative biomaterials with regenerative properties (e.g., osteoinduction and osteoconduction), and physical stimuli to enhance bone regeneration

    The interactions between gold nanoparticles and their self-assembly

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    Gold nanoparticles (AuNPs) are one of the most promising building blocks to fabricate versatile nanostructures. Such nanostructures have the great potential to enable new gold-based nanomaterials or nanocomposites with specific properties by precisely controlling the interactions (potential energies and/or forces) between them. In other words, the interactions between AuNPs are therefore regarded as one of the key factors governing particles’ self-assembly process that can drive multiple AuNPs to form ordered structures as required. Quantifying the interactions between them and understanding of their self-assembly process are of great importance and yet still challenging. In this study, molecular dynamics (MD) simulations are performed to calculate the interactions (e.g., potential energies) between AuNPs. The MD results reveal that a more effective force model between AuNPs can be developed as a function of their surface separation compared with the conventional Hamaker equation. In addition, MD simulations examine several effects (i.e., particle size, shape, rotation, surface patch, surfactant, as well as configuration) on their interactions. The results demonstrate that the different impacts of these factors (e.g., the hindrance of surfactant). Apart from spherical gold nanoparticles, interactions between gold nanorods (AuNRs) are also be quantified by MD simulations. The interparticle forces of AuNRs can be expressed as a function of their surface separation and the rotation angle since the rotational movement is applied on AuNR. Further, the MD-derived interparticle force models of gold nanospheres are integrated into discrete element method (DEM) to explore their self-assembly process. To the best of our knowledge, this might be the first time that the MD-based interparticle force models are integrated into DEM to explore the self-assembly process of gold nanoparticles. The results show that ordered nanostructures are ultimately constructed. Specifically, the mean coordination number (CN) of AuNPs (3 nm in size) is up to 5.99 and two major large clusters is observed under the simulation conditions at the equilibrated state. The completion of this study not only allows us to evaluate the interactions between AuNPs by MD simulation, but profoundly, the MD-DEM coupling approach opens a new window to unfold the self-assembly process of AuNPs

    Electroanalytical Overview: The Determination of Levodopa (L-DOPA)

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    L-DOPA (levodopa) is a therapeutic agent which is the most effective medication for treating Parkinson’s disease, but it needs dose optimization, and therefore its analytical determination is required. Laboratory analytical instruments can be routinely used to measure L-DOPA but are not always available in clinical settings and traditional research laboratories, and they also have slow result delivery times and high costs. The use of electroanalytical sensing overcomes these problems providing a highly sensitivity, low-cost, and readily portable solution. Consequently, we overview the electroanalytical determination of L-DOPA reported throughout the literature summarizing the endeavors toward sensing L-DOPA, and we offer insights into future research opportunities

    Nanoparticle synthesis and their integration into polymer-based fibers for biomedical applications

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    The potential of nanoparticles as effective drug delivery systems combined with the versatility of fibers has led to the development of new and improved strategies to help in the diagnosis and treatment of diseases. Nanoparticles have extraordinary characteristics that are helpful in several applications, including wound dressings, microbial balance approaches, tissue regeneration, and cancer treatment. Owing to their large surface area, tailor-ability, and persistent diameter, fibers are also used for wound dressings, tissue engineering, controlled drug delivery, and protective clothing. The combination of nanoparticles with fibers has the power to generate delivery systems that have enhanced performance over the individual architectures. This review aims at illustrating the main possibilities and trends of fibers functionalized with nanoparticles, focusing on inorganic and organic nanoparticles and polymer-based fibers. Emphasis on the recent progress in the fabrication procedures of several types of nanoparticles and in the description of the most used polymers to produce fibers has been undertaken, along with the bioactivity of such alliances in several biomedical applications. To finish, future perspectives of nanoparticles incorporated within polymer-based fibers for clinical use are presented and discussed, thus showcasing relevant paths to follow for enhanced success in the field.This research was funded by the Portuguese Foundation for Science and Technology (FCT) via grants UIDP/00264/2020 of 2C2T Strategic Project 2020–2023 and project PTDC/CTMTEX/28074/2017. This project has been funded by a Research Grant (2022) from the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) to J.C.A., J.M.D. and C.S.M. also acknowledge FCT for PhD grants 2020.07387.BD and 2020.08547.BD, respectively, and H.P.F. for auxiliary researcher contract 2021.02720.CEECIND
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