Nano-delivery platforms for bacterial gene transformation: suitability and challenges.

Nano-scale particles (NPs) have gained increased interest as non-viral vectors for nucleic acid delivery due to their ability to penetrate through unabraded cell membranes. The previous studies performed have evaluated the nanomaterials for their microbial transformation proficiency but have not compared the relative efficacy. The present study aims to identify the most proficient nano-delivery vehicle among the chemically synthesized/functionalized non-metal oxide, metal/metal oxide, and carbon-based (carbon nanotube (CNT), graphene oxide (GO)) nanomaterial(s) (NMs) for the transformation of two gram-negative bacteria, i.e., Escherichia coli and Agrobacterium tumefaciens. The microscopy and spectroscopy studies helped to identify the interaction, adhesion patterns, transformation efficiencies, better delivery, and expression of the target gfp gene by use of NMs. Loading of pgfp on all NMs imparted protection to DNAse I attack except ZnO NPs with maximum by chitosan, layered double hydroxide (LDH), and GO NM-plasmid DNA conjugates. The CNTs and GO significantly enhanced the extra- and intra-cellular protein content, respectively, in both bacteria. However, GO and CNT significantly decreased the cell viability in a time-dependent manner while AuNPs exhibited negligible cell toxicity. Therefore, this study identified the comparative efficiency of metal/metal oxide, non-metal oxide, and carbon nanomaterials with AuNPs as the most biosafe while LDH and chitosan NPs being the most proficient alternative tools for the genetic transformation of gram-negative bacteria by simple incubation method.

Surface molecularly imprinted polymers based on magnetic multi-walled carbon nanotubes for the highly selective purification of resveratrol from crude extracts of Vitis vinifera, Arachis hypogaea, and Polygonum cuspidatum.

In this work, surface molecularly imprinted polymers based on magnetic multi-walled carbon nanotubes were prepared for the specific recognition and adsorption of resveratrol. The functionalization of magnetic multi-walled carbon nanotubes and the synthesis process of surface molecularly imprinted polymers were optimized. Characterizations were performed to demonstrate the successful synthesis of the imprinted materials. The imprinted materials showed satisfactory adsorption capacity of resveratrol (45.73 ± 1.72 mg/g) and excellent selectivity (imprinting factor 2.89 ± 0.15). In addition, the imprinted materials were used as adsorbents in molecularly imprinted solid-phase extraction for the purification of resveratrol from crude extracts of some food and medicinal resources, achieving recoveries of 93.69%-95.53% with high purities of 88.37%-92.33%. Moreover, the purified products exhibited extremely strong free radical scavenging activity compared with crude extracts. Overall, this work provided a promising approach for the highly selective purification of resveratrol from natural resources, which would contribute to the application of this valuable compound in the food/nutraceutical fields.

A Review on the Design of Carbon-Based Nanomaterials as MRI Contrast Agents.

The administration of magnetic resonance imaging (MRI) contrast agents (CAs) has been conducted since 1988 by clinicians to enhance the clarity and interpretability of MR images. CAs based on gadolinium chelates are the clinical standard used worldwide for the diagnosis of various pathologies, such as the detection of brain lesions, the visualization of blood vessels, and the assessment of soft tissue disorders. However, due to ongoing concerns associated with the safety of gadolinium-based contrast agents, considerable efforts have been directed towards developing contrast agents with better relaxivities, reduced toxicity, and eventually combined therapeutic modalities. In this context, grafting (or encapsulating) paramagnetic metals or chelates onto (within) carbon-based nanoparticles is a straightforward approach enabling the production of contrast agents with high relaxivities while providing extensive tuneability regarding the functionalization of the nanoparticles. Here, we provide an overview of the parameters defining the efficacy of lanthanide-based contrast agents and the subsequent developments in the field of nanoparticular-based contrast agents incorporating paramagnetic species.

Carbon-Based Nanomaterials Electrodes of Ionic Soft Actuators: From Initial 1D Structure to 3D Composite Structure for Flexible Intelligent Devices.

With the rapid development of autonomous and intelligent devices driven by soft actuators, ion soft actuators in flexible intelligent devices have several advantages over other actuators, including their light weight, low voltage drive, large strain, good flexibility, fast response, etc. Traditional ionic polymer metal composites have received a lot of attention over the past decades, but they suffer from poor driving performance and short service lives since the precious metal electrodes are not only expensive, heavy, and labor-intensive, but also prone to cracking with repeated actuation. As excellent candidates for the electrode materials of ionic soft actuators, carbon-based nanomaterials have received a lot of interest because of their plentiful reserves, low cost, and excellent mechanical, electrical, and electrochemical properties. This research reviewed carbon-based nanomaterial electrodes of ion soft actuators for flexible smart devices from a fresh perspective from 1D to 3D combinations. The design of the electrode structure is introduced after the driving mechanism of ionic soft actuators. The details of ionic soft actuator electrodes made of carbon-based nanomaterials are then provided. Additionally, a summary of applications for flexible intelligent devices is provided. Finally, suggestions for challenges and prospects are made to offer direction and inspiration for further development.

Cement Composites with Carbon-Based Nanomaterials for 3D Concrete Printing Applications - A Review.

3D concrete printing (3DCP) is an emerging additive manufacturing technology in the construction industry. Its challenges lie in the development of high-performance printable materials and printing processes. Recently developed carbon-based nanomaterials (CBNs) such as graphene, graphene oxide, graphene nanoplatelets, and carbon nanotubes, have various applications due to their exceptional mechanical, chemical, thermal, and electrical characteristics. CBNs also have found potential applications as a concrete ingredient as they enhance the microstructure and modify concrete properties at the molecular level. This paper focuses on state-of-the-art studies on CBNs, 3DCP technology, and CBNs in conventional and 3D printable cement-based composites including CBN dispersion techniques, concrete mixing methods, and fresh and hardened properties of concrete. Furthermore, the current limitations and future perspectives of 3DCP using CBNs to produce high-quality composite mixtures are discussed.

3D Printable Geopolymer Composites Reinforced with Carbon-Based Nanomaterials - A Review.

Three-dimensional (3D) geopolymer printing (3DGP) technology is a rapidly evolving digital fabrication method used in the construction industry. This technology offers significant benefits over 3D concrete printing in terms of energy saving and reduced carbon emissions, thus promoting sustainability. 3DGP technology is still evolving, and researchers are striving to develop high-performance printable materials and different methods to improve its robustness and efficiency. Carbon-based nanomaterials (CBNs) with beneficial properties have a wide range of applications in various fields, including as concrete/geopolymer systems in construction. This paper comprehensively reviews the research progress on carbon-based nanomaterials (CBNs) used to develop extrusion-based 3D geopolymer printing (3DGP) technology, including dispersion techniques, mixing methods, and the materials' performance. The rheological, mechanical, durability, and other characteristics of these materials are also examined. Furthermore, the existing research limitations and the prospects of using 3DGP technology to produce high-quality composite mixtures are critically evaluated.

Pharmaceutical pollution fingerprinting and waterbodies remediation using waste-derived carbon dots as sustainable advanced nanomaterials.

The conversion of biomass waste into high-value nanomaterials such as carbon dots might represent a great advancement towards a circular economy system. Biomass wastes are an excellent choice as carbon precursors because of their wide availability, abundance, chemical composition, and eco-friendly nature. Moreover, their use as a raw material might decrease the total cost of the synthesis processes and reduce the environmental impacts. In addition, the complex composition of biomass leads to carbon dots with abundant functional groups, which in turn enhances water dispersibility and photoluminescence properties. In this manner, the effective transformation of biomass wastes into carbon dots reduces environmental pollution through the inadequate management of waste while producing carbon dots with enhanced performances. Therefore, this review describes biomass wastes as potential candidates for the synthesis of carbon dots through different synthesis methods. In addition, we have analyzed the great potential of biomass-derived carbon dots (CDs) for the degradation and detection of emerging pharmaceutical pollutants by promoting a circular economy approach. Finally, we identified current challenges to propose possible research directions for the large-scale and sustainable synthesis of high-quality biomass-derived CDs.

Therapeutic applications of carbon nanomaterials in renal cancer.

Carbon nanomaterials (CNMs), including carbon nanotubes (CNTs), graphene, and nanodiamonds (NDs), have shown great promise in detecting and treating numerous cancers, including kidney cancer. CNMs can increase the sensitivity of diagnostic techniques for better kidney cancer identification and surveillance. They enable targeted medicine delivery specifically to tumour locations, with little effect on healthy tissue. Because of their unique chemical and physical characteristics, they can avoid the body's defence mechanisms, making it easier to accumulate where tumours exist. Consequently, CNMs provide more effective drug delivery to kidney cancer cells. It also helps in improving the efficacy of treatment. This review explores the potential of several CNMs in improving therapeutic strategies for kidney cancer. We briefly covered the physicochemical properties and therapeutic applications of CNMs. Additionally, we discussed how structural modifications in CNMs enhance their precision in treating renal cancer. A thorough overview of CNM-based gene, peptide, and drug delivery strategies for the treatment of renal cancer is presented in this review. It covers information on other CNM-based therapeutic approaches, such as hyperthermia, photodynamic therapy, and photoacoustic therapy. Also, the interactions of CNMs with the tumour microenvironment (TME) are explored, including modulation of the immune response, regulation of tumour hypoxia, interactions between CNMs and TME cells, effects of TME pH on CNMs, and more. Finally, potential side effects of CNMs, such as toxicity, bio corona formation, enzymatic degradation, and biocompatibility, are also discussed.

Functional rewiring across spinal injuries via biomimetic nanofiber scaffolds.

The regrowth of severed axons is fundamental to reestablish motor control after spinal-cord injury (SCI). Ongoing efforts to promote axonal regeneration after SCI have involved multiple strategies that have been only partially successful. Our study introduces an artificial carbon-nanotube based scaffold that, once implanted in SCI rats, improves motor function recovery. Confocal microscopy analysis plus fiber tracking by magnetic resonance imaging and neurotracer labeling of long-distance corticospinal axons suggest that recovery might be partly attributable to successful crossing of the lesion site by regenerating fibers. Since manipulating SCI microenvironment properties, such as mechanical and electrical ones, may promote biological responses, we propose this artificial scaffold as a prototype to exploit the physics governing spinal regenerative plasticity.

An overview of synthetic methods and applications of photoluminescence properties of carbon quantum dots.

Carbon quantum dots (CQDs) are promising carbonaceous nanomaterials fortuitously discovered in 2004. CQDs are the rising stars in the nanotechnology ensemble because of their unique properties and widespread applications in sensing, imaging, medicine, catalysis, and optoelectronics. CQDs are notable for their excellent solubility and effective luminescence and, as a result, they are also known as carbon nanolights. Many strategies are used for the efficient and economical preparation of CQDs; however, CQDs prepared from waste or green sustainable methods have greater requirements due to their safety and ease of synthesis. Sustainable chemical strategies for CQDs have been developed, emphasizing green synthetic methodologies based on 'top-down' and 'bottom-up' approaches. This review summarizes many such studies relevant to the development of sustainable methods for photoluminescent CQDs. Furthermore, we have emphasized recent advances in CQDs' photoluminescence applications in chemical and biological fields. Finally, a brief overview of synthetic processes using the green source and their associated applications are tabulated, providing a clear understanding of the new optoelectronic materials.

Carbon dot and silver nanoparticle-based fluorescent probe for the determination of sulfite and bisulfite via inner-filter effect and competitive redox reactions.

A new sensitive fluorescent probe (CDs-AgNP/H2O2) for detecting sulfite and bisulfite (SO32- and HSO3-) based on the inner-filter effect (IFE) between silver nanoparticles (AgNPs) and carbon dots (CDs) was developed. Because of the spectral overlap between the absorption of AgNPs and the excitation of CDs, the fluorescence of CDs can be quenched by AgNPs owing to the IFE. H2O2 weakens the IFE and restores the fluorescence due to the oxidation of AgNPs by H2O2. However, the existence of SO32-/HSO3- can quench the fluorescence again as a result of redox reaction between SO32-/HSO3- and H2O2. The results showed a broad linear range of 20-200 µM with a low limit of detection (3.02 µM) toward SO32-/HSO3-. The combination of IFE and redox reaction led to improvement of the sensitivity and selectivity. The probe was implemented to measure SO32-/HSO3- in various agricultural products and foods with acceptable results (80.6 to 118.9% recovery).

The Emerging Development of Multicolor Carbon Dots.

As a relatively new type of fluorescent carbon-based nanomaterials, multicolor carbon dots (MCDs) have attracted much attention because of their excellent biocompatibility, tunable photoluminescence (PL), high quantum yield, and unique electronic and physicochemical properties. The multicolor emission characteristics of carbon dots (CDs) obviously depend on the carbon source precursor, reaction conditions, and reaction environment, which directly or indirectly determines the multicolor emission characteristics of CDs. Therefore, this review is the first systematic classification and summary of multiple regulation methods of synthetic MCDs and reviews the recent research progress in the synthesis of MCDs from a variety of precursor materials such as aromatic molecules, small organic molecules, and natural biomass, focusing on how different regulation methods produce corresponding MCDs. This review also introduces the innovative applications of MCDs in the fields of biological imaging, light-emitting diodes (LEDs), sensing, and anti-counterfeiting due to their excellent PL properties. It is hoped that by selecting appropriate adjustment methods, this review can inspire and guide the future research on the design of tailored MCDs, and provide corresponding help for the development of multifunctional MCDs.

Hydrothermal synthesis of chiral carbon dots.

Nanocolloids that are cumulatively referred to as nanocarbons, attracted significant attention during the last decade because of facile synthesis methods, water solubility, tunable photoluminescence, easy surface modification, and high biocompatibility. Among the latest development in this reserach area are chiral nanocarbons exemplified by chiral carbon dots (CDots). They are expected to have applications in sensing, catalysis, imaging, and nanomedicine. However, the current methods of CDots synthesis show often contradictory chemical/optical properties and structural information that required a systematic study with careful structural evaluation. Here, we investigate and optimize chiroptical activity and photoluminescence of L- and D-CDots obtained by hydrothermal carbonization of L- and D-cysteine, respectively. Nuclear magnetic resonance spectroscopy demonstrates that they are formed via gradual dehydrogenation and condensation reactions of the starting amino acid leading to particles with a wide spectrum of functional groups including aromatic cycles. We found that the chiroptical activity of CDots has an inverse correlation with the synthesis duration and temperature, whereas the photoluminescence intensity has a direct one, which is associated with degree of carbonization. Also, our studies show that the hydrothermal synthesis of cysteine in the presence of boric acid leads to the formation of CDots rather than boron nitride nanoparticles as was previously proposed in several reports. These results can be used to design chiral carbon-based nanoparticles with optimal chemical, chiroptical, and photoluminescent properties.

A composite adsorbent of graphene quantum dots, mesoporous carbon, and molecularly imprinted polymer to extract nonsteroidal anti-inflammatory drugs in milk.

A composite magnetic adsorbent was developed by embedding graphene quantum dots (GQDs), silica-modified magnetite (Fe3O4-SiO2), and mesoporous carbon (MPC) into a molecularly imprinted polymer (GQDs/Fe3O4-SiO2/MPC/MIP). The adsorbent was applied to extract nonsteroidal anti-inflammatory drugs (NSAIDs) in milk. The MIP was formed via a sol-gel copolymerization using flurbiprofen, diflunisal, and mefenamic acid as template molecules, 3-aminopropyltriethoxysilane as a monomer, and tetraethyl orthosilicate as a cross-linker. GQDs and MPC enhanced affinity binding between NSAIDs and the adsorbent through π-π stacking, hydrogen bonding, and hydrophobic interaction. The Fe3O4-SiO2 nanoparticles embedded in the composite adsorbent enabled its rapid isolation from the sample solution. The extracted NSAIDs were quantified by high-performance liquid chromatography and exhibited good linearity from 1.0 to 100.0 µg L-1 for flurbiprofen and 0.5 to 100.0 µg L-1 for diflunisal and mefenamic acid, respectively. The limits of detection ranged from 0.5 to 1.0 µg L-1. Recoveries of NSAIDs from spiked milk samples ranged from 81.4 to 93.7%, with RSDs below 7%. The reproducibility of the fabricated adsorbent was good and in the optimal conditions, the developed adsorbent could be used for up to six extraction-desorption cycles.

Immunotoxicity of Carbon-Based Nanomaterials, Starring Phagocytes.

In the field of science, technology and medicine, carbon-based nanomaterials and nanoparticles (CNMs) are becoming attractive nanomaterials that are increasingly used. However, it is important to acknowledge the risk of nanotoxicity that comes with the widespread use of CNMs. CNMs can enter the body via inhalation, ingestion, intravenously or by any other route, spread through the bloodstream and penetrate tissues where (in both compartments) they interact with components of the immune system. Like invading pathogens, CNMs can be recognized by large numbers of receptors that are present on the surface of innate immune cells, notably monocytes and macrophages. Depending on the physicochemical properties of CNMs, i.e., shape, size, or adsorbed contamination, phagocytes try to engulf and process CNMs, which might induce pro/anti-inflammatory response or lead to modulation and disruption of basic immune activity. This review focuses on existing data on the immunotoxic potential of CNMs, particularly in professional phagocytes, as they play a central role in processing and eliminating foreign particles. The results of immunotoxic studies are also described in the context of the entry routes, impacts of contamination and means of possible elimination. Mechanisms of proinflammatory effect depending on endocytosis and intracellular distribution of CNMs are highlighted as well.

Recent Developments in Carbon-Based Nanocomposites for Fuel Cell Applications: A Review.

Carbon-based nanocomposites have developed as the most promising and emerging materials in nanoscience and technology during the last several years. They are microscopic materials that range in size from 1 to 100 nanometers. They may be distinguished from bulk materials by their size, shape, increased surface-to-volume ratio, and unique physical and chemical characteristics. Carbon nanocomposite matrixes are often created by combining more than two distinct solid phase types. The nanocomposites that were constructed exhibit unique properties, such as significantly enhanced toughness, mechanical strength, and thermal/electrochemical conductivity. As a result of these advantages, nanocomposites have been used in a variety of applications, including catalysts, electrochemical sensors, biosensors, and energy storage devices, among others. This study focuses on the usage of several forms of carbon nanomaterials, such as carbon aerogels, carbon nanofibers, graphene, carbon nanotubes, and fullerenes, in the development of hydrogen fuel cells. These fuel cells have been successfully employed in numerous commercial sectors in recent years, notably in the car industry, due to their cost-effectiveness, eco-friendliness, and long-cyclic durability. Further; we discuss the principles, reaction mechanisms, and cyclic stability of the fuel cells and also new strategies and future challenges related to the development of viable fuel cells.

Cu/Cux S-Embedded N,S-Doped Porous Carbon Derived in Situ from a MOF Designed for Efficient Catalysis.

The reasonable design of the precursor of a carbon-based nanocatalyst is an important pathway to improve catalytic performance. In this study, a simple solvothermal method was used to synthesize [Cu(TPT)(2,5-tdc)] ⋅ 2H2 O (Cu-MOF), which contains N and S atoms, in one step. Further in-situ carbonization of the Cu-MOF as the precursor was used to synthesize Cu/Cux S-embedded N,S-doped porous carbon (Cu/Cux S/NSC) composites. The catalytic activities of the prepared Cu/Cux S/NSC were investigated through catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The results show that the designed Cu/Cux S/NSC has exceptional catalytic activity and recycling stability, with a reaction rate constant of 0.0256 s-1 , and the conversion rate still exceeds 90 % after 15 cycles. Meanwhile, the efficient catalytic reduction of dyes (CR, MO, MB and RhB) confirmed its versatility. Finally, the active sites of the Cu/Cux S/NSC catalysts were analyzed, and a possible multicomponent synergistic catalytic mechanism was proposed.

Effects of Metallic and Carbon-Based Nanomaterials on Human Pancreatic Cancer Cell Lines AsPC-1 and BxPC-3.

Pancreatic cancer, due to its asymptomatic development and drug-resistance, is difficult to cure. As many metallic and carbon-based nanomaterials have shown anticancer properties, we decided to investigate their potential use as anticancer agents against human pancreatic adenocarcinoma. The objective of the study was to evaluate the toxic properties of the following nanomaterials: silver (Ag), gold (Au), platinum (Pt), graphene oxide (GO), diamond (ND), and fullerenol (C60(OH)40) against the cell lines BxPC-3, AsPC-1, HFFF-2, and HS-5. The potential cytotoxic properties were evaluated by the assessment of the cell morphology, cell viability, and cell membrane damage. The cancer cell responses to GO and ND were analysed by determination of changes in the levels of 40 different pro-inflammatory proteins. Our studies revealed that the highest cytotoxicity was obtained after the ND treatment. Moreover, BxPC-3 cells were more sensitive to ND than AsPC-1 cells due to the ND-induced ROS production. Furthermore, in both of the cancer cell lines, ND caused an increased level of IL-8 and a decreased level of TIMP-2, whereas GO caused only decreased levels of TIMP-2 and ICAM-1 proteins. This work provides important data on the toxicity of various nanoparticles against pancreatic adenocarcinoma cell lines.

Importance of Surface Topography in Both Biological Activity and Catalysis of Nanomaterials: Can Catalysis by Design Guide Safe by Design?

It is acknowledged that the physicochemical properties of nanomaterials (NMs) have an impact on their toxicity and, eventually, their pathogenicity. These properties may include the NMs' surface chemical composition, size, shape, surface charge, surface area, and surface coating with ligands (which can carry different functional groups as well as proteins). Nanotopography, defined as the specific surface features at the nanoscopic scale, is not widely acknowledged as an important physicochemical property. It is known that the size and shape of NMs determine their nanotopography which, in turn, determines their surface area and their active sites. Nanotopography may also influence the extent of dissolution of NMs and their ability to adsorb atoms and molecules such as proteins. Consequently, the surface atoms (due to their nanotopography) can influence the orientation of proteins as well as their denaturation. However, although it is of great importance, the role of surface topography (nanotopography) in nanotoxicity is not much considered. Many of the issues that relate to nanotopography have much in common with the fundamental principles underlying classic catalysis. Although these were developed over many decades, there have been recent important and remarkable improvements in the development and study of catalysts. These have been brought about by new techniques that have allowed for study at the nanoscopic scale. Furthermore, the issue of quantum confinement by nanosized particles is now seen as an important issue in studying nanoparticles (NPs). In catalysis, the manipulation of a surface to create active surface sites that enhance interactions with external molecules and atoms has much in common with the interaction of NP surfaces with proteins, viruses, and bacteria with the same active surface sites of NMs. By reviewing the role that surface nanotopography plays in defining many of the NMs' surface properties, it reveals the need for its consideration as an important physicochemical property in descriptive and predictive toxicology. Through the manipulation of surface topography, and by using principles developed in catalysis, it may also be possible to make safe-by-design NMs with a reduction of the surface properties which contribute to their toxicity.

Special Issue "Advanced Nanomaterials Based Gas Sensors".

During the last several years, according to the works published in research journals, many nanostructured materials have been tested as sensing materials for gas-sensing applications. This trend has been observed for both metal oxides as well as carbon-based nanomaterials. More recently, it has also been extended to other materials based on chalcogenides. The field of applications for these sensors is very wide, including air quality, industrial safety and medical diagnosis, using different transducing mechanisms. Therefore, in this Special Issue, we have put together recent advances in this area.