Pharmacological Role of Functionalized Gold Nanoparticles in Disease Applications

Gold has always been regarded as a symbol of nobility, and its shiny golden appearance has always attracted the attention of many people. Gold has good ductility, molecular recognition properties, and good biocompatibility. At present, gold is being used in many fields. When gold particles are as small as several nanometers, their physical and chemical properties vary with their size in nanometers. The surface area of a nano-sized gold surface has a special effect. Therefore, gold nanoparticles can, directly and indirectly, give rise to different biological activities. For example, if the surface of the gold is sulfided. Various substances have a strong chemical reactivity and are easy to combine with sulfhydryl groups; hence, nanogold is often used in biomedical testing, disease diagnosis, and gene detection. Nanogold is easy to bind to proteins, such as antibodies, enzymes, or cytokines. In fact, scientists use nanogold to bind special antibodies, as a tool for targeting cancer cells. Gold nanoparticles are also directly cytotoxic to cancer cells. For diseases caused by inflammation and oxidative damage, gold nanoparticles also have antioxidant and anti-inflammatory effects. Based on these unique properties, gold nanoparticles have become the most widely studied metal nanomaterials. Many recent studies have further demonstrated that gold nanoparticles are beneficial for humans, due to their functional pharmacological properties in a variety of diseases. The content of this review will be the application of gold nanoparticles in treating or diagnosing pressing diseases, such as cancers, retinopathy, neurological diseases, skin disorders, bowel diseases, bone cartilage disorders, cardiovascular diseases, infections, and metabolic syndrome. Gold nanoparticles have shown very obvious therapeutic and application potential.     

Antimicrobial Treatment of Different Metal Oxide Nanoparticles: A Critical Review

Many nanomaterials can be used as metal oxides (Ti, Ag, Zn, Cu, Mg, Ca, Ce, Yt, Al). Metal oxide nanoparticles have strong antimicrobial properties. The oxides that play a large role as antimicrobial agents can be divided into two major groups based on their mechanism of action i.e., those that involve oxidation and those that inhibit the production of Reactive Oxygen Species (ROS). Previous studies have shown that, toxic metals like silver and titanium, and their metals oxides, employ the ROS‐mediated mechanism that leads to oxidative stress‐related cytotoxicity, cancer, and heart diseases. Oxidative stress further leads to increased ROS production and also delays the cellular processes involved in wound heal‐ ing. Other metal oxide nanoparticles, like Y₂O₃, CeO₂ and Al₂O₃ act as free radical scavengers. Out of these, aluminium oxide nanoparticles are more effective antimicrobial agents, than the other metal oxide nanoparticles. A combination of Al₂O₃ and other antimicrobial agents such as TiO₂ may act as ideal antimicrobial agents, along with possessing free radical scavenging activity. This critical review aims to study the antimicrobial properties of different metal oxide nanoparticles and the mechanism of action in‐ volved, besides comparing their efficacy to eliminate bacteria.     

Intrinsic therapeutic applications of noble metal nanoparticles: past, present and future

Biomedical nanotechnology is an evolving field having enormous potential to positively impact the health care system. Important biomedical applications of nanotechnology that may have potential clinical applications include targeted drug delivery, detection/diagnosis and imaging. Basic understanding of how nanomaterials, the building blocks of nanotechnology, interact with the cells and their biological consequences are beginning to evolve. Noble metal nanoparticles such as gold, silver and platinum are particularly interesting due to their size and shape dependent unique optoelectronic properties. These noble metal nanoparticles, particularly of gold, have elicited a lot of interest for important biomedical applications because of their ease of synthesis, characterization and surface functionalization. Furthermore, recent investigations are demonstrating another promising application of these nanomaterials as self-therapeutics. To realize the potential promise of these unique inorganic nanomaterials for future clinical translation, it is of utmost importance to understand a few critical parameters; (i) how these nanomaterials interact with the cells at the molecular level; (ii) how their biodistribution and pharmacokinetics influenced by their surface and routes of administration; (iii) mechanism of their detoxification and clearance and (iv) their therapeutic efficacy in appropriate disease model. Thus in this critical review, we will discuss the various clinical applications of gold, silver and platinum nanoparticles with relevance to above parameters. We will also mention various routes of synthesis of these noble metal nanoparticles. However, before we discuss present research, we will also look into the past. We need to understand the discoveries made before us in order to further our knowledge and technological development (318 references).     

Toxicological Effects of Metal Nanoparticles Employed in Biomedicine: Biocompatibility,Clinical Trials,and Future Perspective

Metal nanoparticles play a crucial role in the medical industry due to its desirable properties such as antimicrobial activity, anti-cancer property, and its application in disease diagnostics. These properties enable the nanoparticles to be used as efficient medical devices for various treatments as well as drug delivery systems. Despite all the positives, metal nanoparticles are known for causing toxicity in the living system. The toxicological effects of metal nanoparticles are due to their size, surface*e coating, and the dose administered. Therefore, it is important to study the toxic effects of these nanoparticles before they are used as medical devices for various treatments. This review focuses on the five major metal nanoparticles used in the medical field, namely; silver, gold, iron oxide, zinc oxide, and titanium dioxide nanoparticles. The non-exhaustive review consists of an introduction to the toxicological effects of these nanoparticles, the biocompatibility, and the current and future clinical perspective on metal nanoparticles.     

基于金属纳米簇的荧光传感平台的最新研究进展

荧光纳米生物传感平台由于具有灵敏度高、选择性好、操作简单、成本低、实时监测等特点,吸引了广泛的关注.近年来,随着纳米技术的飞速发展,具有纳米结构的材料(纳米材料)在生物传感领域显示出独特的优势.与传统材料相比,纳米材料显示出独特的物化性质,如光学、电学、机械、催化和磁性等.金属(如Au、Ag、Cu及其合金)纳米簇(MN...     

Dispersions, novel nanomaterial sensors and nanoconjugates based on carbon nanotubes

Nanomaterials are structures with dimensions characteristically much below 100 nm. The unique physical properties (e.g., conductivity, reactivity) have placed these nanomaterials in the forefront of emerging technologies. Significant enhancement of optical, mechanical, electrical, structural, and magnetic properties are commonly found through the use of novel nanomaterials. One of the most exciting classes of nanomaterials is represented by the carbon nanotubes. Carbon nanotubes, including single-wall carbon nanotubes, multi-wall carbon nanotubes, and concentric tubes have been shown to possess superior electronic, thermal, and mechanical properties to be attractive for a wide range of potential applications They sometimes bunch to form “ropes” and show great potential for use as highly sensitive electronic (bio)sensors due to the very small diameter, directly comparable to the size of single analyte molecules and that every single carbon atom is in direct contact with the environment, allowing optimal interaction with nearby molecules. Composite materials based on integration of carbon nanotubes and some other materials to possess properties of the individual components with a synergistic effect have gained growing interest. Materials for such purposes include conducting polymers, redox mediators and metal nanoparticles. These tubes provide the necessary building blocks for electronic circuits and afford new opportunities for chip miniaturization, which can dramatically improve the scaling prospects for the semiconductor technologies and the fabrication of devices, including field-effect transistors and sensors. Carbon nanotubes are one of the ideal materials for the preparation of nanoelectronic devices and nanosensors due to the unique electrical properties, outstanding electrocatalytic properties, high chemical stability and larger specific surface area of nanotubes. Carbon nanotubes are attractive material for supercapacitors due to their unique one-dimensional mesoporous structure, high specific surface area, low resistivity and good chemical stability. Nanoscaled composite materials based on carbon nanotubes have been broadly used due to their high chemical inertness, non-swelling effect, high purity and rigidity. The integration of carbon nanotubes with organics, biomaterials and metal nanoparticles has led to the development of new hybrid materials and sensors. Hybrid nanoscale materials are well established in various processes such as organic and inorganic compounds, nucleic acid detachment, protein separation, and immobilization of enzymes. Those nanostructures can be used as the building blocks for electronics and nanodevices because uniform organic and metal coatings with the small and monodisperse domain sizes are crucial to optimize nanoparticle conductivity and to detect changes in conductivity and absorption induced by analyte adsorption on these surfaces. The highly ordered assembly of zero-dimensional and one-dimensional nanoparticles is not only necessary for making functional devices, but also presents an opportunity to develop novel collective properties.     

贵金属复合纳米粒子的研究进展

贵金属复合纳米粒子具有不同于单组分纳米粒子的独特的光、电和催化等物理与化学性能,是构筑新型功能复合材料的重要单元,在传感器、光学材料、催化剂及生物领域都有着重要应用,已成为当前纳米材料科学研究领域中的前沿和热点。本文主要评述了具有核壳、异质结构以及合金结构的贵金属复合纳米粒子的制备、物理与化学性能及应用等方面的研究进展。     

Thin metal nanostructures: synthesis,properties and applications

Two-dimensional nanomaterials, especially graphene and single- or few-layer transition metal dichalcogenide nanosheets, have attracted great research interest in recent years due to their distinctive physical, chemical and electronic properties as well as their great potentials for a broad range of applications. Recently, great efforts have also been devoted to the controlled synthesis of thin nanostructures of metals, one of the most studied traditional materials, for various applications. In this minireview, we review the recent progress in the synthesis and applications of thin metal nanostructures with a focus on metal nanoplates and nanosheets. First of all, various methods for the synthesis of metal nanoplates and nanosheets are summarized. After a brief introduction of their properties, some applications of metal nanoplates and nanosheets, such as catalysis, surface enhanced Raman scattering (SERS), sensing and near-infrared photothermal therapy are described.     

Redox-transmetalation process as a generalized synthetic strategy for core-shell magnetic nanoparticles

Although multicomponent core-shell type nanomaterials are one of the highly desired structural motifs due to their simultaneous multifunctionalities, the fabrication strategy for such nanostructures is still in a primitive stage. Here, we present a redox-transmetalation process that is effective as a general protocol for the fabrication of high quality and well-defined core-shell type bimetallic nanoparticles on the sub-10 nm scale. Various core-shell type nanomaterials including Co@Au, Co@Pd, Co@Pt, and Co@Cu nanoparticles are fabricated via transmetalation reactions. Compared to conventional sequential reduction strategies, this transmetalation process has several advantages for the fabrication of core-shell type nanoparticles: (i) no additional reducing agent is needed and (ii) spontaneous shell layer deposition occurs on top of the core nanoparticle surface and thus prevents self-nucleation of secondarily added metals. We also demonstrate the versatility of these core-shell structures by transferring Co@Au nanoparticles from an organic phase to an aqueous phase via a surface modification process. The nanostructures, magnetic properties, and reaction byproducts of these core-shell nanoparticles are spectroscopically characterized and identified, in part, to confirm the chemical process that promotes the core-shell structure formation.     

Surface-mediated production of hydroxyl radicals as a mechanism of iron oxide nanoparticle biotoxicity

Emerging applications of nanosized iron oxides in nanotechnology introduce vast quantities of nanomaterials into the human environment, thus raising some concerns. Here we report that the surface of γ-Fe(2)O(3) nanoparticles 20-40 nm in diameter mediates production of highly reactive hydroxyl radicals (OH(?)) under conditions of the biologically relevant superoxide-driven Fenton reaction. By conducting comparative spin-trapping EPR experiments, we show that the free radical production is attributed primarily to the catalytic reactions at the nanoparticles' surface rather than being caused by the dissolved metal ions released by the nanoparticles as previously thought. Moreover, the catalytic centers on the nanoparticle surface were found to be at least 50-fold more effective in OH(?) radical production than the dissolved Fe(3+) ions. Conventional surface modification methods such as passivating the nanoparticles' surface with up to 935 molecules of oleate or up to 18 molecules of bovine serum albumin per iron oxide core were found to be rather ineffective in suppressing production of the hydroxyl radicals. The experimental protocols developed in this study could be used as one of the approaches for developing analytical assays for assessing the free radical generating activity of a variety of nanomaterials that is potentially related to their biotoxicity.     

Magnetic nanomaterials for the removal,separation and preconcentration of organic and inorganic pollutants at trace levels and their practical applications: A review

The presence of organic and inorganic pollutants in nature even in very small concentrations threatens human and other living bodies health and makes it significant to remove, separate and preconcentrate these pollutants. Recently magnetic nano sorbents has been used frequently in the separation and preconcentration of these pollutants. The use of magnetic nano sorbents modified with inorganic and organic species has widespread applications in the solid phase extraction (SPE) studies due to its many unique properties. These modified nano sorbents are preferred due to their advantages such as high adsorption capacities and large surface areas. This review examined different types of magnetic materials such as magnetic carbon-based nano sorbents, inorganic nano sorbents with magnetic properties, magnetized biosorbents, magnetic metal-organic frameworks, and magnetized ionic liquids used in SPE studies. In this study, a comprehensive and systematic review of the separation and preconcentration of analytes such as heavy metal ions, drug active substances, pesticides, dyes, hormone disruptors, etc with SPE methods using magnetic nanomaterials has been revealed. Future aspects and challenges that may be encountered are discussed.     

Synthesis and modification of silicon nanosheets and other silicon nanomaterials

Silicon nanomaterials and nanostructures exhibit different properties from those of bulk silicon materials based on quantum confinement effects. They are expected to lead to the development of new applications of silicon, in addition to wide use in semiconductor devices. Aside from industrial interest, intriguing issues of academic interest still remain with respect to the origins of their characteristic properties. Zero- and one-dimensional crystalline silicon nanomaterials have been synthesized, to date, by using many methods and there has been rapid progress in size control and modification procedures. However, there have been only a few examples of silicon nanomaterials with atomic-order thickness akin to carbon nanomaterials, such as two-dimensional silicon nanosheets. Moreover, mass production of silicon nanomaterials with relatively low cost is not easily achievable, due to the typically severe conditions required for fabrication, such as high temperature and ultralow pressure. Recently, we have developed a soft synthetic method for silicon nanosheets with chemical surface modification in a solution process. This review provides methods for the synthesis and modification of silicon nanosheets and other silicon nanomaterials with examples of their potential applications.     

聚合物纳米光诊疗剂的制备与应用新进展

共轭聚合物纳米颗粒是由π-共轭有机聚合物组成的尺寸在1~100nm范围内的新型有机纳米材料。与传统的有机小分子、半导体量子点和无机纳米材料相比,聚合物纳米颗粒具有光学性质特殊、结构多样、表面易修饰和生物相容性好等优点,因而被广泛应用于生物成像、传感与检测、载药和治疗等领域。本文主要围绕聚合物纳米颗粒的制备方法、性质结构和生物相容性等方面,重点介绍了聚合物纳米颗粒作为光诊疗剂在荧光成像、光声成像,以及光动力和光热治疗领域的研究进展,并对聚合物纳米颗粒的发展前景和未来面临的挑战进行了探讨。     

Impact of nanomaterials on high-throughput separation methodologies

Due to the unique properties, such as their large surface to volume ratio and easy modification, nanomaterials have recently been studied as effective sorbents in the field of separation science. It has proven to be more effective and efficient to use nanoparticles (NPs) as a stationary phase in solid-phase extraction separation. In addition, NPs can be also used as buffer additives in capillary electrophoresis separation. This review highlights recent developments in high-throughput separation methodologies employing nanomaterials such as carbon nanotubes, gold nanoparticles and magnetic NPs etc.     

Synthesis and assembly of rare earth nanostructures directed by the principle of coordination chemistry in solution-based process

In this review, several typical nanomaterials are selected to demonstrate the coordination effect on the control of structure/microstructure/texture, surface/interface, particle size and morphology. Based on the principle of coordination chemistry, with some solution-based methods including solvothermal treatment and the thermolysis of metal complex precursors, a series of novel nanostructured rare earth compounds, such as ultra-small colloidal ceria nanoparticles, highly homogenous and stable ceria–zirconia solid solutions, and high-quality rare earth oxide and fluoride nanocrystals, etc., have been prepared by elaborately controlling the synthetic parameters and reaction kinetics. In order to reveal the mechanisms of synthesis, assembly, and properties, the phase, microstructure, texture, and surface state have been characterized systematically. The main applications of coordination chemistry principle in the synthesis and assembly of rare earth nanocrystals have been summarized, which also can be extended to direct the fabrication of other nanomaterials.     

Nanomaterials of high surface energy with exceptional properties in catalysis and energy storage

The properties of nanomaterials for use in catalytic and energy storage applications strongly depends on the nature of their surfaces. Nanocrystals with high surface energy have an open surface structure and possess a high density of low-coordinated step and kink atoms. Possession of such features can lead to exceptional catalytic properties. The current barrier for widespread industrial use is found in the difficulty to synthesise nanocrystals with high-energy surfaces. In this critical review we present a review of the progress made for producing shape-controlled synthesis of nanomaterials of high surface energy using electrochemical and wet chemistry techniques. Important nanomaterials such as nanocrystal catalysts based on Pt, Pd, Au and Fe, metal oxides TiO(2) and SnO(2), as well as lithium Mn-rich metal oxides are covered. Emphasis of current applications in electrocatalysis, photocatalysis, gas sensor and lithium ion batteries are extensively discussed. Finally, a future synopsis about emerging applications is given (139 references).     

Gold nanoparticle probes for the detection of mercury, lead and copper ions

Monitoring the levels of potentially toxic metal (PTM) ions (e.g., Hg(2+), Pb(2+), Cu(2+)) in aquatic ecosystems is important because these ions can have severe effects on human health and the environment. Gold (Au) nanomaterials are attractive sensing materials because of their unique size- and shape-dependent optical properties. This review focuses on optical assays for Hg(2+), Pb(2+), and Cu(2+) ions using functionalized Au nanomaterials. The syntheses of functionalized Au nanomaterials are discussed. We briefly review sensing approaches based on changes in absorbance resulting from metal ion-induced aggregation of Au nanoparticles (NPs) or direct deposition of metal ions onto Au NPs. The super-quenching properties of Au NPs allow them to be employed in 'turn on' and 'turn off' fluorescence approaches for the sensitive and selective detection of Hg(2+), Pb(2+), and Cu(2+) ions. We highlight approaches based on fluorescence quenching through analyte-induced aggregation or the formation of metallophilic complexes of Au nanodots (NDs). We discuss the roles of several factors affecting the selectivity and sensitivity of the nanosensors toward the analytes: the size of the Au nanomaterial, the length and sequence of the DNA or the nature of the thiol, the surface density of the recognition ligand, and the ionic strength and pH of the buffer solution. In addition, we emphasize the potential of using new nanomaterials (e.g., fluorescent silver nanoclusters) for the detection of PTM ions.     

Stable isotope labeling of nanomaterials for biosafety evaluation and drug development

Quantitative information, such as environmental migration, absorption, biodistribution, biotransformation, and elimination, is fundamental and essential for the nanosafety evaluations of nanomaterials. Due to the complexity of biological and environmental systems, it is challenging to develop quantitative approaches and tools that could characterize intrinsic behaviors of nanomaterials in the organisms. The isotopic tracers are ideal candidates to tune the physical properties of nanomaterials while preserving their chemical properties. In this review article, we summarized the stable isotope labeling methods of nanomaterials for evaluating their environmental and biological effects. The skeleton labeling protocols of carbon nanomaterials and metal/metal oxide nanoparticles were introduced. The advantages and disadvantages of stable isotope labeling were discussed in comparison with other quantitative methods for nanomaterials. The quantitative information of nanomaterials in environmental and biological systems was summarized along with the biosafety data. The benefits for drug development of nanomedicine were analyzed based on the targeting effects, persistent accumulation, and safety. Finally, the challenges and future perspectives of stable isotope labeling in nanoscience and nanotechnology were discussed.     

Recent developments of melatonin related antioxidant compounds

Melatonin is known for its radical scavenger activity, which is related to its ability to protect cells from different kinds of oxidative stress. Oxidative stress has been implicated in the development of neurodegenerative diseases like Parkinson, Alzheimer's disease, Huntington's disease, epileptic seizures, stroke, and as a contributor to aging and some cancer types. The antioxidant properties of melatonin include scavenging free radicals and the regulation of the activity and expression of antioxidant and pro-oxidant enzymes. Due to its free radical scavenger and antioxidant properties, multiple melatonin-related compounds such as melatonin metabolites and synthetic analogues are under investigation to determine which exhibit the highest activity with the lowest side effects. This review addresses recent studies with melatonin and related compounds.     

Nanomaterials and lab-on-a-chip technologies

Lab-on-a-chip (LOC) platforms have become important tools for sample analysis and treatment with interest for DNA, protein and cells studies or diagnostics due to benefits such as the reduced sample volume, low cost, portability and the possibility to build new analytical devices or be integrated into conventional ones. These platforms have advantages of a wide set of nanomaterials (NM) (i.e. nanoparticles, quantum dots, nanowires, graphene etc.) and offer excellent improvement in properties for many applications (i.e. detectors sensitivity enhancement, biolabelling capability along with other in-chip applications related to the specificities of the variety of nanomaterials with optical, electrical and/or mechanical properties). This review covers the last trends in the use of nanomaterials in microfluidic systems and the related advantages in analytical and bioanalytical applications. In addition to the applications of nanomaterials in LOCs, we also discuss the employment of such devices for the production and characterization of nanomaterials. Both framed platforms, NMs based LOCs and LOCs for NMs production and characterization, represent promising alternatives to generate new nanotechnology tools for point-of-care diagnostics, drug delivery and nanotoxicology applications.