Control Of Surface Properties Research Articles

Theoretical Modeling of Chemical Equilibrium in Weak Polyelectrolyte Layers on Curved Nanosystems.

Surface functionalization with end-tethered weak polyelectrolytes (PE) is a versatile way to modify and control surface properties, given their ability to alter their degree of charge depending on external cues like pH and salt concentration. Weak PEs find usage in a wide range of applications, from colloidal stabilization, lubrication, adhesion, wetting to biomedical applications such as drug delivery and theranostics applications. They are also ubiquitous in many biological systems. Here, we present an overview of some of the main theoretical methods that we consider key in the field of weak PE at interfaces. Several applications involving engineered nanoparticles, synthetic and biological nanopores, as well as biological macromolecules are discussed to illustrate the salient features of systems involving weak PE near an interface or under (nano)confinement. The key feature is that by confining weak PEs near an interface the degree of charge is different from what would be expected in solution. This is the result of the strong coupling between structural organization of weak PE and its chemical state. The responsiveness of engineered and biological nanomaterials comprising weak PE combined with an adequate level of modeling can provide the keys to a rational design of smart nanosystems.

Atmospheric-pressure plasma assisted engineering of polymer surfaces: From high hydrophobicity to superhydrophilicity

To engineer polymer surfaces with long-lasting wettability properties and with high coating stability in aqueous media, we investigated the surface wettability of polyethylene terephthalate (PET) films treated by radio frequency (RF) atmospheric-pressure plasma. By combining plasma activation and hexamethyldisiloxane (HMDSO)-based plasma polymerization, stable PET surface properties from highly hydrophobic to superhydrophilic were achieved. The results clearly showed that the wettability of PET surfaces could be tuned from stable high hydrophobicity (>140°) to stable superhydrophilicity (<10°) with a minimized aging effect by using plasma activation of plasma deposited coatings. Surface roughness increase and CH3 groups introduction are primarily responsible for the coating hydrophobization, while the introduction of more oxygen-containing polar functional groups is the main factor leading to superhydrophilization. Importantly, the coatings engineered by this unique combination showed high stability in water over 14 days. Overall, this work contributes to the easy-to-overlook links between plasma activation and plasma polymerization, demonstrates that atmospheric-pressure RF plasma can be a versatile tool to control surface properties of polymers in a wide range from high hydrophobicity to superhydrophilicity with high coating stability in aqueous media and a negligible aging effect, which is promising for emerging biomedical applications.

Self-assemblying behaviour of activated microporous carbon microspheres functionalized via water filtration process

Activated carbon spheres are truly innovative materials with their porous micro/nanostructure that gives them tunable and controllable surface properties (i.e. high surface area, size and orientation of pores etc.). They have great potential for applications as adsorbents for cleaning/purification of water, air and chemical substances, catalyst supports, energy storage and conversion, adsorption of chemical warfare agents, filtration and others. Magnetic functionalization of highly porous and high surface areas of activated carbons have received considerable attention for their more sophisticated and advanced utilization as “smart” and “self-assemblying” purposes. In this study, a novel fabrication technique was used to synthesize activated high compressive strength nanoporous carbon spheres. The functionalization via adsorption/impregnation of magnetic substances was occured during a well-known water treatment-filtering route to fill the pores with nano-sized magnetic particles. Unusually active and dynamic interactions of the magnetic phases were observed upon contacting into each other revealing self-assemblying behaviour of activated carbon microspheres. Dynamic magnetical interaction of self assemblying behaviour of these spheres may have further and advanced applications for variety of purposes.

Engineering of 2D Ti3C2 MXene Surface Charge and Its Influence on Biological Properties.

Current trends in the field of MXenes emphasize the importance of controlling their surface features for successful application in biotechnological areas. The ability to stabilize the surface properties of MXenes has been demonstrated here through surface charge engineering. It was thus determined how changing the surface charges of two-dimensional (2D) Ti3C2 MXene phase flakes using cationic polymeric poly-L-lysine (PLL) molecules affects the colloidal and biological properties of the resulting hybrid 2D nanomaterial. Electrostatic adsorption of PLL on the surface of delaminated 2D Ti3C2 flakes occurs efficiently, leads to changing an MXene’s negative surface charge toward a positive value, which can also be effectively managed through pH changes. Analysis of bioactive properties revealed additional antibacterial functionality of the developed 2D Ti3C2/PLL MXene flakes concerning Escherichia. coli Gram-negative bacteria cells. A reduction of two orders of magnitude of viable cells was achieved at a concentration of 200 mg L−1. The in vitro analysis also showed lowered toxicity in the concentration range up to 375 mg L−1. The presented study demonstrates a feasible approach to control surface properties of 2D Ti3C2 MXene flakes through surface charge engineering which was also verified in vitro for usage in biotechnology or nanomedicine applications.

Targeted Dendrimer-Coated Magnetic Nanoparticles for Selective Delivery of Therapeutics in Living Cells.

Nanoparticles are widely used as theranostic agents for the treatment of various pathologies, including cancer. Among all, dendrimers-based nanoparticles represent a valid approach for drugs delivery, thanks to their controllable size and surface properties. Indeed, dendrimers can be easily loaded with different payloads and functionalized with targeting agents. Moreover, they can be used in combination with other materials such as metal nanoparticles for combinatorial therapies. Here, we present the formulation of an innovative nanostructured hybrid system composed by a metallic core and a dendrimers-based coating that is able to deliver doxorubicin specifically to cancer cells through a targeting agent. Its dual nature allows us to transport nanoparticles to our site of interest through the magnetic field and specifically increase internalization by exploiting the T7 targeting peptide. Our system can release the drug in a controlled pH-dependent way, causing more than 50% of cell death in a pancreatic cancer cell line. Finally, we show how the system was internalized inside cancer cells, highlighting a peculiar disassembly of the nanostructure at the cell surface. Indeed, only the dendrimeric portion is internalized, while the metal core remains outside. Thanks to these features, our nanosystem can be exploited for a multistage magnetic vector.

A universal growth strategy for DNA-programmed quantum dots on graphene oxide surfaces

The emerging materials of semiconductor quantum dots/graphene oxide (QDs/GO) hybrid composites have recently attracted intensive attention in materials science and technology due to their potential applications in electronic and photonic devices. Here, a simple and universal strategy to produce DNA-programmed semiconductor quantum dots/graphene oxide (QDs/GO) hybrid composites with controllable sizes, shapes, compositions, and surface properties is reported. This proof-of-concept work successfully demonstrates the use of sulfhydryl modified single-stranded DNA (S-ssDNA) as a ‘universal glue’ which can adsorb onto GO easily and provide the growth sites to synthesize CdS QDs, CdSe QDs, CdTe QDs and CdTeSe QDs with distinctive sizes, shapes and properties. Also, adapting this method, other graphene oxide-based hybrid materials which are easily synthesized in aqueous solution, including oxides, core–shell structure QDs and metal nanocrystals, would be possible. This method provided a universal strategy for the synthesis and functional realization of graphene -based nanomaterials.

Formulation of monomyristin-loaded polyester nanoparticles with controlled surface properties

Monomyristin (MM), a monoacylglycerol with very low water solubility, has been reported to exhibit anti-proliferative property against cervical cancer cells. In order to increase its bioavailability, MM was encapsulated for the first time inside dextran-covered poly(lactic acid) nanoparticles. The use of dextran-based stabilizers with convenient structural characteristics was shown to provide important end-use properties to particle suspensions like colloidal stability during extensive washing steps or in the presence of high ionic strengths, easy reconstitution after lyophilization without particle aggregation in the absence of added cryoprotectant. Furthermore, immobilization of proteins at the surface of loaded particles was investigated with Bovine Serum Albumin and Transferrin using functionalized dextran-based stabilizers. The nature of links (covalent or non-covalent) between proteins and dextran-based superficial layer was discussed.

Plasma Treatment of Poly(ethylene terephthalate) Films and Chitosan Deposition: DC- vs. AC-Discharge.

Plasma treatment is one of the most promising tools to control surface properties of materials tailored for biomedical application. Among a variety of processing conditions, such as the nature of the working gas and time of treatment, discharge type is rarely studied, because it is mainly fixed by equipment used. This study aimed to investigate the effect of discharge type (direct vs. alternated current) using air as the working gas on plasma treatment of poly(ethylene terephthalate) films, in terms of their surface chemical structure, morphology and properties using X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy and contact angle measurements. The effect of the observed changes in terms of subsequent chitosan immobilization on plasma-treated films was also evaluated. The ability of native, plasma-treated and chitosan-coated films to support adhesion and growth of mesenchymal stem cells was studied to determine the practicability of this approach for the biomedical application of poly(ethylene terephthalate) films.

Molecular Dynamics Simulation of the Influence of Nanoscale Structure on Water Wetting and Condensation.

Recent advances in the microfabrication technology have made it possible to control surface properties at micro- and nanoscale levels. Functional surfaces drastically change wettability and condensation processes that are essential for controlling of heat transfer. However, the direct observation of condensation on micro- and nanostructure surfaces is difficult, and further understanding of the effects of the microstructure on the phase change is required. In this research, the contact angle of droplets with a wall surface and the initial condensation process were analyzed using a molecular dynamics simulation to investigate the impact of nanoscale structures and their adhesion force on condensation. The results demonstrated the dependence of the contact angle of the droplets and condensation dynamics on the wall structure and attractive force of the wall surface. Condensed water droplets were adsorbed into the nanostructures and formed a water film in case of a hydrophilic surface.

Controlled synthesis of three dimensional mesoporous C3N4 with ordered porous structure for room temperature Suzuki coupling reaction

We report on the synthesis of mesoporous graphitic C3N4 (MGCN-6) with 3D porous structure and Ia3d symmetry and controllable surface properties through a simple polymerization of an environmentally benign and non-toxic guanidine hydrochloride as a C and N precursor using KIT-6 with variable pore sizes as templates for Suzuki coupling reaction. The pore diameters (3.1–4.2 nm), specific surface areas (207–303 m2 g−1), and the specific pore volumes (0.58–0.71 cm3 g−1) of the MGCN-6 materials are finely controlled by varying the pore size of the templates used. The nano cavities of MGCN-6 with the highest specific surface area and a free amine groups are effectively utilized to chelate with Pd(OAC)2 and applied the prepared catalysts for Suzuki coupling reaction between aryl halides with phenylboronic acid derivatives under very mild and sustainable reaction conditions. The Pd(OAC)2/MGCN-6 is found to be very active and stable and exhibits an excellent reactivity and selectivity for all of substrates regardless of aryl halides with electron-withdrawing and electron donating groups at room temperature. The activity of the Pd(OAC)2/MGCN-6 is much higher than that of non-porous bulk graphitic carbon nitride and 2D mesoporous carbon nitride.

Leaf-Inspired Micro- and Nanoengineered Surfaces for Controlled Hydrophilic and Hydrophobic Properties

In various industries, it is important to manipulate engineering platforms by controlling hydrophilic and hydrophobic properties. Here, we report on a simple, tunable replication method that mimics the unique surface of micro- and nanotopographies of common camellia, fragrant plantain, and lotus leaf, with properties that range from hydrophilic to hydrophobic. Using lithographic technology in combination with thermal- or ultraviolet (UV)-sensitive materials such as polycaprolactone (PCL) and polyurethane acrylate (PUA), we designed and fabricated hydrophilic and hydrophobic surfaces using a single material (i.e., PCL and PUA with controlled surface properties). The morphologies of the mimetic leaves were analyzed, which showed that flat, hexagonal, and protuberance topographies were successfully generated using the same material. There was no change in the chemical bending or crystalline structure of the mimetic platform compared with the flat platforms. This demonstrates that our leaf-inspired micro- and nanostructures could exhibit hydrophilic and hydrophobic properties, which is an important consideration in designing engineering platforms for various industries.

Effects of carbon concentration on high-hardness plasma-polymer-fluorocarbon film deposited by mid-range frequency sputtering

We propose a method for fabricating high-hardness plasma-polymer-fluorocarbon (PPFC) thin films with controllable optical and surface properties via manipulation of the target composition design and sputtering power density. The carbon/polytetrafluoroethylene (PTFE) composite polymeric material targets with the low electrical resistance were prepared by press-molding using a mechanically mixed powder of PTFE, carbon nanotubes, and graphite. The composite targets showed electrical sheet resistances of 0.1–100 Ω/sq. PPFC thin films were deposited by mid-range frequency (MF) sputtering at power densities within 0.62~4.92 W/cm2. The maximum surface hardness of the PPFC thin film was 4.75 GPa, which was 21.6 times higher than that of fluorocarbon thin film sputtered from PTFE under the same conditions. With the increase of the carbon concentration in the target, the carbon cross-linking density of the PPFC thin film increased but the fluorine concentration decreased. The concentration of fluorine in the PPFC thin films grew with increasing sputtering power density. The MF sputtered carbon-rich PPFC thin films are controllable with physical properties of optical transmittance, surface hardness and surface water repellency which could be applied as protective layers for transparent flexible devices.

Guiding mesenchymal stem cell differentiation using mesoporous silica nanoparticle-based films

The development of smart interfaces that can guide tissue formation is of great importance in the field of regenerative medicine. Nanoparticles represent an interesting class of materials that can be used to enhance regenerative treatments by enabling close control over surface properties and directing cellular responses. Moreover, nanoparticles can be used to provide temporally controlled delivery of (multiple) biochemical compounds. Here, we exploited the cargo loading and surface functionalization properties of mesoporous silica nanoparticles (MSNs) to design films that can guide human mesenchymal stem cell (hMSC) differentiation towards the osteogenic lineage. We developed biocompatible MSN-based films that support stem cell adhesion and proliferation and demonstrated that these MSN films simultaneously allowed efficient local delivery of biomolecules without effecting film integrity. Films loaded with the osteogenesis-stimulating drug dexamethasone (Dex) were able to induce osteogenic differentiation of hMSCs in vitro. Dex delivery from the films led to increased alkaline phosphatase levels and matrix mineralization compared to directly supplementing Dex to the medium. Furthermore, we demonstrated that Dex release kinetics can be modulated using surface modifications with supported lipid bilayers. Together, these data demonstrate that MSN films represent an interesting approach to create biomaterial interfaces with controllable biomolecule release and surface properties to improve the bioactivity of biomaterials. Statement of significanceEngineering surfaces that can control cell and tissue responses is one of the major challenges in biomaterials-based regenerative therapies. Here, we demonstrate the potential of mesoporous silica nanoparticles (MSNs) as drug-delivering surface coatings. First, we show differentiation of mesenchymal stem cells towards the bone lineage when in contact with MSN films loaded with dexamethasone. Furthermore, we demonstrate that modification of MSNs with supported lipid bilayer allows control over drug release dynamics and cell shape. Given the range of loadable cargos and the tunability of release kinetics, MSN coatings can be used to mimic the sequential appearance of bioactive factors during tissue regeneration, which will ultimately lead to biomaterials with improved bioactivity.

Pegylated Metal-Phenolic Networks for Antimicrobial and Antifouling Properties.

Metal-phenolic networks (MPNs) have recently attracted great interest in material chemistry and biomaterials because of their biocompatible, versatile, and multifunctional properties. In this paper, we describe a facile method for preparation of a designable antifouling, antimicrobial, and substrate-independent coating assembled from the coordination of metal ions and catecholic groups. Hydrophilic and catecholic polymers were synthesized by copolymerization of dopamine methacrylamide (DMA) and poly(ethylene glycol)methyl methacrylate (PEGMA) to afford p(PEGMA- co-DMA). To investigate the assembly and formation of MPN films, two different metal ions, that is, ferrous (FeII) and ferric (FeIII) ions, to react with p(PEGMA- co-DMA) were compared. The binding constants between iron ions and p(PEGMA- co-DMA) have been investigated by ultraviolet-visible spectroscopy (UV-vis). Measurements with atomic force microscopy, contact angle goniometer, and X-ray photoelectron spectroscopy (XPS) were carried out to quantitatively analyze the surface morphology, wettability, and interfacial elemental compositions of coatings, respectively. Moreover, ellipsometric measurements were performed to obtain the film thickness and grafting density. In addition, the pH-responsive property of the MPN films was investigated at different pH values, showing fast disassembly of the networks at low pH. The antifouling properties of the obtained coatings were analyzed by exposing them to bacteria of Escherichia coli and Staphylococcus epidermidis and NIH-3T3 fibroblasts under observation of fluorescence microscopy and cell imaging analysis. The findings suggest that the MPN from complexation of p(PEGMA- co-DMA) and metal ions provides excellent antifouling, pH-responsive, and biocompatible properties on a wide range of substrates. Furthermore, the released iron ions can effectively suppress the growth of bacteria. Accordingly, the new coating architecture offers a universal feature to control surface properties and functionalization for various applications.

Controlling surface properties of electrospun polyphenylsulfone using plasma treatment and X-ray photoelectron spectroscopy

Plasma treatment is an efficient method to modify organic surfaces. In this work electrospun polyphenylsulfone was systematically subjected to low-pressure microwave plasma and atmospheric-pressure coplanar barrier discharge in order to control the surface chemistry, which is important for controlling surface properties. Polar anchor groups such as keto/aldehyde groups and especially carboxylic acid groups affect hydrophilicity. The composition of plasma-induced chemical anchor groups can be monitored (and thus controlled) by X-ray photoelectron spectroscopy. The atmospheric-pressure plasma provided subtle oxidation, and the low-pressure plasma provided significant oxidation that resulted in polyphenylsulfone surfaces with a very high hydrophilicity. The low-pressure plasma treated polyphenylsulfone exhibited a significant age effect over 212 days, which was attributed to a diffusion phenomenon where the polyphenylsulfone surface becomes enriched in non-oxidated polyphenylsulfone. It was shown that the improved hydrophilicity will diminish but not vanish in time.

Asymmetries in Porous Membranes: Fabrication of Anodic Aluminum Oxide Membranes with Double-Sized Nanopores and Controlled Surface Properties

Recently, anodic aluminum oxide (AAO) membranes with ordered and monodispersed nanopores have attracted significant attention because the pore sizes and lengths of the AAO membranes can be systematically controlled by changing the anodization parameters. Asymmetries of geometry, wettability, charge, and polarity in nanoporous AAO membranes are now highly desired for applications such as drug delivery, membrane filtration, and catalysis. Although the asymmetries in AAO membranes have been widely studied, AAO membranes whose nanopores simultaneously possess more than two asymmetric properties still need to be developed. In this work, we present a simple method to fabricate asymmetric AAO membranes by combining the post-treatments with the three-step anodization method. The asymmetries of the AAO membranes simultaneously possessing larger nanopores with higher hydrophobicity and smaller nanopores with lower hydrophobicity are characterized by scanning electron microscopy, water contact angle measurements, an...

Hydrogel-coated basalt fibre with superhydrophilic and underwater superoleophobic performance for oil-water separation

Materials with controlled surface properties show great potential for various applications. In this paper, we reported a method to prepare a superhydrophilic fabric consisting of basalt fibre (BF) and konjac glucomannan (KGM). Different techniques were employed to study the morphology and surface information of the developed materials. The results showed that the KGM was deacetylated to form a hydrogel when processed in an alkali condition, and the excellent film-forming performance of the hydrogel led to the formation of a coating layer on BF fabric. The coating endowed the developed fabric with enhanced mechanical performance and superhydrophilicity in air condition. Interestingly, the material, subjected to a water condition, exhibited a stable superoleophobicity as confirmed by the extremely low adhesion to oil and remarkable resistance to the corrosive liquids, thus holding the promise to be a suitable candidate for separating various oil-water mixtures.

Glyco-Platelets with Controlled Morphologies via Crystallization-Driven Self-Assembly and Their Shape-Dependent Interplay with Macrophages.

Two-dimensional (2D) materials are of great significance to the materials community as a result of their high surface area and controllable surface properties. However, controlled preparation of biodegradable 2D structures with biological activity is difficult. In this work we demonstrate that by careful selection of building block structures and assembly conditions it is possible to use crystallization-driven self-assembly (CDSA) to assemble well-defined 2D nanostructures from poly(l-lactide) (PLLA)-based diblock glycopolymers. 1D glyco-cylinders and 2D diamond-shaped glyco-platelets are produced, where the underlying formation mechanism is revealed by dissipative particle dynamics simulations. Furthermore, we demonstrate that assembly of thepolymers under mild degradation provides a straightforward route to hollow-cored platelets, a morphology that has previously proven laborious to access. The well-defined sizes and shapes of the glyco-platelets allow us to investigate macrophage activation efficiency and demonstrate clear size and shape effects, pointing toward potential applications in immunology.

(Invited) The Mechanical Bond As a Tool to Control Surface and Electronic Properties of SWNTs

The chemical mofidication of SWNTs typically aims at modifying their surface properties (to make them more processible, or to improve interface with other materials) and/or their electronic properties (to fine tune them for specific applications). Both covalent and supramolecular strategies have been explored towards those ends.[1] We will present strategies towards the synthesis of mechanically interlocked derivatives of SWNTs (MINTs), which are rotaxane-type materials in which the SWNTs are threaded through organic macrocycles, so that they are interfaced through mechanical bonds (see image, scale bar is 1 nm).[2] With the synthetic strategies established, we will focus on the the effect of the mechanical bond on the properties of SWNTs and show that such effect is unique, and clearly different from the noninterlocked, supramolecular compounds.[3] More specifically, we will report how to use the mechanical bond to improve the interface between SWNTs and polymeric materials, to achieve significantly improved mechanical properties.[4] We will also show that the organic macrocycles can be used to modulate the electronic properties of SWNTs, which in turn influence their catalytic properties.[5] [1] Rao, R.; Pint, C. L.; Islam, A. E.; Weatherup, R. S.; Hofmann, S.; Meshot, E. R.; Wu, F.; Zhou, C.; Dee, N.; Amama, P. B.; Carpena-Nuñez, J.; Shi, W.; Plata, D. L.; Penev, E. S.; Yakobson, B. I.; Balbuena, P. B.; Bichara, C.; Futaba, D. N.; Noda, S.; Shin, H.; Kim, K. S.; Simard, B.; Mirri, F.; Pasquali, M.; Fornasiero, F.; Kauppinen, E. I.; Arnold, M.; Cola, B. A.; Nikolaev, P.; Arepalli, S.; Cheng, H.-M.; Zakharov, D. N.; Stach, E. A.; Zhang, J.; Wei, F.; Terrones, M.; Geohegan, D. B.; Maruyama, B.; Maruyama, S.; Li, Y.; Adams, W. W.; Hart, A. J. Carbon Nanotubes and Related Nanomaterials: Critical Advances and Challenges for Synthesis toward Mainstream Commercial Applications. ACS Nano 2018, DOI: 10.1021/acsnano.8b06511. [2] a) de Juan, A.; Pouillon, Y.; Ruiz-Gonzalez, L.; Torres-Pardo, A.; Casado, S.; Martin, N.; Rubio, A.; Perez, E. M. Mechanically Interlocked Single-Wall Carbon Nanotubes. Angew. Chem., Int. Ed. 2014, 53, 5394-5400; b) Lopez-Moreno, A.; Perez, E. M. Pyrene-based mechanically interlocked SWNTs. Chem. Commun. 2015, 51, 5421-5424; Leret, S.; Pouillon, Y.; Casado, S.; Navio, C.; Rubio, A.; Perez, E. M. Bimodal supramolecular functionalization of carbon nanotubes triggered by covalent bond formation. Chem. Sci. 2017, 8, 1927-1935; c) de Juan-Fernandez, L.; Munich, P. W.; Puthiyedath, A.; Nieto-Ortega, B.; Casado, S.; Ruiz-Gonzalez, L.; Perez, E. M.; Guldi, D. M. Interfacing porphyrins and carbon nanotubes through mechanical links. Chem Sci 2018, 9 (33), 6779-6784; d) For a review, see: Perez, E. M. Putting Rings around Carbon Nanotubes. Chem. Eur. J. 2017, 23 (52), 12681-12689. [3] Martinez-Perinan, E.; de Juan, A.; Pouillon, Y.; Schierl, C.; Strauss, V.; Martin, N.; Rubio, A.; Guldi, D. M.; Lorenzo, E.; Perez, E. M. The mechanical bond on carbon nanotubes: diameter-selective functionalization and effects on physical properties. Nanoscale 2016, 8 (17), 9254-9264. [4] Lopez-Moreno, A.; Nieto-Ortega, B.; Moffa, M.; de Juan, A.; Bernal, M. M.; Fernandez-Blazquez, J. P.; Vilatela, J. J.; Pisignano, D.; Perez, E. M. Threading through Macrocycles Enhances the Performance of Carbon Nanotubes as Polymer Fillers. ACS Nano 2016, 10 (8), 8012-8018. [5] Blanco, M.; Nieto-Ortega, B.; de Juan, A.; Vera-Hidalgo, M.; López-Moreno, A.; Casado, S.; González, L. R.; Sawada, H.; González-Calbet, J. M.; Pérez, E. M. Positive and negative regulation of carbon nanotube catalysts through encapsulation within macrocycles. Nat. Commun. 2018, 9 (1), 2671. Figure 1

Green Nanotechnology: Advancement in Phytoformulation Research.

The ultimate goal of any scientific development is to increase well-being and human health. Novel strategies are required for the achievement of safe and effective therapeutic treatments beyond the conventional ones, and society needs new requirements for new technologies, moving towards clean and green technology development. Green nanotechnology is a branch of green technology that utilizes the concepts of green chemistry and green engineering. It reduces the use of energy and fuel by using less material and renewable inputs wherever possible. Green nanotechnology, in phytoformulations, significantly contributes to environmental sustainability through the production of nanomaterials and nanoproducts, without causing harm to human health or the environment. The rationale behind the utilization of plants in nanoparticle formulations is that they are easily available and possess a broad variability of metabolites, such as vitamins, antioxidants, and nucleotides. For instance, gold (Au) nanoparticles have attracted substantial attention for their controllable size, shape, and surface properties. A variety of copper (Cu) and copper oxide (CuO) nanoparticles have also been synthesized from plant extracts. Titanium dioxide and zinc oxide nanoparticles are also important metal oxide nanomaterials that have been synthesized from a number of plant extracts. International and domestic laws, government and private-party programs, regulations and policies are being carefully reviewed and revised to increase their utility and nurture these nanoscale materials for commercialization. Inspiring debates and government initiatives are required to promote the sustainable use of nanoscale products. In this review, we will discuss the potential of the utilization of plant extracts in the advancement of nanotechnology.