Versatile Nanomaterials Research Articles

Self-Assembling Catalytic Peptide Nanomaterials Capable of Highly Efficient Peroxidase Activity.

The self-assembly of short peptides gives rise to versatile nanomaterials capable of promoting efficient catalysis. We have shown that short, seven-residue peptides bind hemin to produce functional catalytic materials which display highly efficient peroxidation activity, reaching a catalytic efficiency of 3×105 m-1 s-1 . Self-assembly is essential for catalysis as non-assembling controls show no activity. We have also observed peroxidase activity even in the absence of hemin, suggesting the potential to alter redox properties of substrates upon association with the assemblies. These results demonstrate the practical utility of self-assembled peptides in various catalytic applications and further support the evolutionary link between amyloids and modern-day enzymes.

Role of Group V Atoms during GaAs Nanowire Growth Revealed by Molecular Dynamics Simulations: Implications in the Formation of Sharp Interfaces

Understanding atomistic mechanisms for catalyst-assisted nanowire growth is an essential step to improve control over the properties of these versatile nanomaterials. However, in silico approaches ...

Atomically Precise Gold Nanoclusters: Towards an Optimal Biocompatible System from a Theoretical-Experimental Strategy.

Potential biomedical applications of gold nanoparticles have increasingly been reported with great promise for diagnosis and therapy of several diseases. However, for such a versatile nanomaterial, the advantages and potential health risks need to be addressed carefully, as the available information about their toxicity is limited and inconsistent. Atomically precise gold nanoclusters (AuNCs) have emerged to overcome this challenge due to their unique features, such as superior stability, excellent biocompatibility, and efficient renal clearance. Remarkably, the elucidation of their structural and physicochemical properties provided by theory-experiment investigations offers exciting opportunities for site-specific biofunctionalization of the nanoparticle surface, which remains a significant concern for most of the materials in the biomedical field. This concept highlights the advantages conferred by atomically precise AuNCs for biomedical applications and the powerful strategy combining computational and experimental studies towards finding an optimal biocompatible AuNCs-based nanosystem.

A new strategy using nanoscale zero-valent iron to simultaneously promote remediation and safe crop production in contaminated soil.

Novel versatile nanomaterials may facilitate strategies for simultaneous soil remediation and agricultural production, but a thorough and mechanistic assessment of efficacy and safety is needed. We have established a new soil remediation strategy using nanoscale zero-valent iron (nZVI) coupled with safe rice production in paddy soil contaminated with pentachlorophenol (PCP). In comparison with rice cultivation in contaminated soil with 100 mg PCP per kg soil but without nZVI, the addition of 100 mg nZVI per kg soil increased grain yield by 47.1-55.0%, decreased grain PCP content by 83.6-86.2% and increased the soil PCP removal rate from 49.9 to 83.9-89.0%. The specific role of nZVI-derived root iron plaque formation in the safe production of rice has been elucidated, and the synergistic effect of nZVI treatment and rice cultivation identified in the nZVI-facilitated rhizosphere microbial degradation of PCP. This work opens a new strategy for the application of nanomaterials in soil remediation that could simultaneously enable safe crop production in contaminated lands.

Rapid fabrication of carbon dots from babul seed powder as green precursor: Antioxidant activity and multicolor imaging

Abstract Carbon dots (CDs) are versatile nanomaterials with high biocompatibility and attractive optical properties. This research presents a microwave assisted rapid inexpensive method of CDs production using babul seed powder as a novel green source. Various parameters of synthesis were optimized and as obtained CDs were characterized by Transmission electronic microscopy (TEM), X-ray diffraction (XRD), UV–Visible, fluorescence, Fourier-transform infrared (FT-IR), Raman and X-ray photoelectron spectroscopic (XPS) techniques. CDs exhibited excellent water solubility and excitation dependent emission that is stable to pH, ionic strength and resistant to photo bleaching. Furthermore, the cytotoxicity of CDs tested on both normal (Human embryonic kidney HEK-293) and cancerous (Human breast adenocarcinoma MCF-7) cell lines disclosed their high biocompatibility. With these admirable properties, CDs were applied as multicolor cellular imaging agents. Furthermore the antioxidant activity of CDs was investigated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay.

Nanomaterials to relieve tumor hypoxia for enhanced photodynamic therapy

This review summarizes recent research progress in versatile nanomaterials for enhanced photodynamic therapy by relieving tumor hypoxia. • This review summarizes recent progress in nanomaterials for enhanced photodynamic therapy by relieving tumor hypoxia. • The methods for constructing these nanomaterials based on characteristic factors in tumor are discussed. • The limitations and prospects of nanomaterials for enhanced photodynamic therapy are also discussed. Photodynamic therapy (PDT) shows great potential for tumor treatment owing to its high spatiotemporal selectivity, minimal invasiveness and patient compliance. However, the therapeutic effect of PDT is seriously hindered by the tumor hypoxia in vivo. Hypoxia is a typical hallmark of the solid tumor microenvironment, which promotes the proliferation, invasion and metastasis of tumor cells. Additionally, the oxygen consumption during PDT will further aggravate the tumor hypoxia, resulting in multiple undesirable side-effects. To resolve these problems, many studies have been conducted to improve the efficacy of PDT by increasing oxygen concentration in tumor. Here, we focus on the current advances in nanomaterials-mediated tumor oxygenation via oxygen-carrying or oxygen-generating strategies to relieve tumor hypoxia. Based on the comprehensive overview, we hope these inspirations in hypoxia-associated anti-tumor therapy will provide perspectives in designing new oxygenation nanomaterials in this promising field.

Self-assembling Peptides in Current Nanomedicine: Versatile Nanomaterials for Drug Delivery.

The development of modern nanomedicine greatly depends on the involvement of novel materials as drug delivery system. In order to maximize the therapeutic effects of drugs and minimize their side effects, a number of natural or synthetic materials have been widely investigated for drug delivery. Among these materials, biomimetic self-assembling peptides (SAPs) have received more attention in recent years. Considering the rapidly growing number of SAPs designed for drug delivery, a summary of how SAPs-based drug delivery systems were designed, would be beneficial. We outlined research works on different SAPs that have been investigated as carriers for different drugs, focusing on the design of SAPs nanomaterials and how they were used for drug delivery in different strategies. Based on the principle rules of chemical complementarity and structural compatibility, SAPs such as ionic self-complementary peptide, peptide amphiphile and surfactant-like peptide could be designed. Determined by the features of peptide materials and the drugs to be delivered, different strategies such as hydrogel embedding, hydrophobic interaction, electrostatic interaction, covalent conjugation or the combination of them could be employed to fabricate SAPs-drug complex, which could achieve slow release, targeted or environment-responsive delivery of drugs. Furthermore, some SAPs could also be combined with other types of materials for drug delivery, or even act as drug by themselves. Various types of SAPs have been designed and used for drug delivery following various strategies, suggesting that SAPs as a category of versatile nanomaterials have promising potential in the field of nanomedicine.

Zero-Valent Iron Nanoparticles for Soil and Groundwater Remediation.

Zero-valent iron has been reported as a successful remediation agent for environmental issues, being extensively used in soil and groundwater remediation. The use of zero-valent nanoparticles have been arisen as a highly effective method due to the high specific surface area of zero-valent nanoparticles. Then, the development of nanosized materials in general, and the improvement of the properties of the nano-iron in particular, has facilitated their application in remediation technologies. As the result, highly efficient and versatile nanomaterials have been obtained. Among the possible nanoparticle systems, the reactivity and availability of zero-valent iron nanoparticles (NZVI) have achieved very interesting and promising results make them particularly attractive for the remediation of subsurface contaminants. In fact, a large number of laboratory and pilot studies have reported the high effectiveness of these NZVI-based technologies for the remediation of groundwater and contaminated soils. Although the results are often based on a limited contaminant target, there is a large gap between the amount of contaminants tested with NZVI at the laboratory level and those remediated at the pilot and field level. In this review, the main zero-valent iron nanoparticles and their remediation capacity are summarized, in addition to the pilot and land scale studies reported until date for each kind of nanomaterials.

Systematic Study of Perfluorocarbon Nanoemulsions Stabilized by Polymer Amphiphiles.

Perfluorocarbon (PFC) nanoemulsions, droplets of fluorous solvent stabilized by surfactants dispersed in water, are simple yet versatile nanomaterials. The orthogonal nature of the fluorous phase promotes the formation of nanoemulsions through a simple, self-assembly process while simultaneously encapsulating fluorous-tagged payloads for various applications. The size, stability, and surface chemistry of PFC nanoemulsions are controlled by the surfactant. Here, we systematically study the effect of the hydrophilic portion of polymer surfactants on PFC nanoemulsions. We find that the hydrophilic block length and identity, the overall polymer hydrophilic/lipophilic balance, and the polymer architecture are all important factors. The ability to modulate these parameters enables control over initial size, stability, payload retention, cellular internalization, and protein adsorption of PFC nanoemulsions. With the insight obtained from this systematic study of polymer amphiphiles stabilizing PFC nanoemulsions, design features required for the optimal material are obtained.

Segmented Microfluidic Flow Reactors for Nanomaterial Synthesis

Microfluidic reactors have remarkably promoted the synthesis and investigation of advanced nanomaterials due to their continuous mode and accelerated heat/mass transfer. Notably, segmented microfluidic flow reactors (SMFRs) are an important class of microfluidic reactors that have been developed to accurately manipulate nanomaterial synthesis by further improvement of the residence time distributions and unique flow behaviors. This review provided a survey of the nanomaterial synthesis in SMFRs for the aspects of fluid dynamics, flow patterns, and mass transfer among and within distinct phases and provided examples of the synthesis of versatile nanomaterials via the use of different flow patterns.

Modular Assembly of Versatile Nanoparticles with Epigallocatechin Gallate

Various nanotechnologies have been extensively developed to prepare nanoparticles with different features for satisfying the requirements of diverse fields, but the current achievements are confined to different material systems for the limited acquisition with desirable properties. Here, we demonstrated a flexible strategy based on the broad selectivity of amines in the condensation of green tea polyphenol-EGCG (epigallocatechin gallate), formaldehyde, and amines for the rational design and preparation of versatile nanomaterials. With EGCG as the sole material system and amines (R–NH2) of various functional R groups as the selectable modules, the modular assembly of polyphenol-activated condensation was straightforward and completed in one step, giving rise to different polyphenolic nanoparticles variable in surface chemistry (−amine, −aldehyde, and −carboxyl), shapes (sphere, dumbbell, walnut), internal structures (solid, hollow, and porous), stimuli responsiveness (-s-s-), and fluorescence. The flexibility of the polyphenolic condensation for versatile nanoparticles was further demonstrated by the incorporation of amino-containing anticancer or antibacterial drugs into polyphenolic nanoparticles as nanodrugs. The present study totally involved the use of 13 different amines to synthesize 18 different nanoparticles, not only convincingly specifying the enormous value of the polyphenolic condensation as platform for modular assembly of versatile nanoparticles but also revolutionizing the current strategies and methodologies for encapsulated applications of tea polyphenols.

Electrostatic properties of inner nanopore surfaces of anodic aluminum oxide membranes upon high temperature annealing revealed by EPR of pH-sensitive spin probes and labels

Anodic aluminum oxide (AAO) membranes are versatile nanomaterials that combine the chemically stable and mechanically robust properties of ceramics with homogeneous nanoscale organization that can be tuned to desirable pore diameters and lengths. The AAO substrates feature high surface area that is readily accessible to large and small molecules, making these nanostructures uniquely suited for many possible applications. Examples include templated self-assembly of macroscopically aligned biological membranes and substrates for heterogeneous catalysis. For further development of such applications, one would like to characterize and tune the electrostatic properties of the inner pore surface as well as the local acidity within the nanochannels. Here, we employed electron paramagnetic resonance (EPR) spectroscopy of a small molecule – ionizable nitroxide – as a reporter of the average local acidity in the nanochannels and the local electrostatic potential in the immediate vicinity of the pore surface. The former was achieved by measuring EPR spectra of this molecular probe diffusing in an aqueous phase confined in the AAO nanochannels while for the latter the nitroxide was covalently attached to the hydroxyl group of the alumina surface. We show that the local acidity within the nanochannels is increased by as much as ≈1.48 pH units vs. the pH of bulk solution by decreasing the pore diameter down to ca. 31 nm. Furthermore, the positive surface charge of the as-prepared AAO could be decreased and even switched to a negative surface charge upon annealing the membranes first to 700 °C and then to 1200 °C. For as-prepared AAO, the local electrostatic potential reaches ψ= (163 ± 5) mV for the nitroxide label covalently attached to AAO and located about 0.5 nm away from the surface. Overall, we demonstrate that the acid-based properties of the aqueous volume confined by the AAO nanopores pores can be tuned by either changing the pore diameter from ca. 71 to 31 nm or by thermal annealing to switch the sign of the surface charge. These observations provide a simple and robust means to tailor these versatile high-surface-area nanomaterials for specific applications that depend on acid-base equilibria.

Acetal-Functionalized Pillar[5]arene: A pH-Responsive and Versatile Nanomaterial for the Delivery of Chemotherapeutic Agents.

Acetal-functionalized pillar[5]arene (Ac-PA[5]) was prepared as a pH-responsive biomaterial. This biomaterial could be fabricated into nanoparticles with a narrow size distribution by an emulsion protocol. PA[5]-based nanoparticles were used to deliver anti-tumor drugs (paclitaxel and doxorubicin) in vitro. PA[5]-based nanoparticles were discovered to be a versatile drug delivery system (DDS) to incorporate a fluorescent dye (fluorescein) or a targeting group (folic acid) via host-guest interactions. The resulting DDS could be used for the purpose of bioimaging or targeted delivery. Acetal-functionalization renders the system acid-labile to release encapsulated cargo during cell internalization, which is confirmed by confocal laser scanning microscopy (CLSM). A folic-acid-modified DDS shows a 5.1-fold enhancement in bioactivity in vitro due to the targeting effect. This DDS is a platform to conveniently integrate multiple functions.

Efficient Removal of Pb(II) from Aqueous Solution using Zinc Oxide/Graphene Oxide Composite

Due to the rapid development of industrialization over the years, the enhancement on heavy metals removal technology are becoming more urgent. Graphene oxide (GO) gained attention as adsorbents due to high surface area and high affinity towards heavy metals removal. However, its tendency for agglomeration and difficulty in phase separation urges more researches done to address its drawback. Zinc oxide (ZnO), a versatile nanomaterial, has been discovered to have high affinity towards heavy metals removal, tendency to spread out across GO sheet and ease of handling. Therefore, in this study, zinc oxide/graphene oxide nanocomposites (ZnO/GO) were synthesized as adsorbents for the removal of Pb(II) from aqueous solution. The synthesized composite was characterized using Fourier-transform Infrared Spectrometry (FT-IR), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD), and had confirmed the chemically bonding of ZnO on GO. From the batch test, the optimum adsorbent dosage and initial pH for Pb(II) adsorption using ZnO/GO were 0.16 g/L and at pH 5, respectively, with the adsorption capacity of Pb(II) at 418.78 mg/g. The most rapid adsorption had occurred in the first 30 minutes, and the equilibrium time was achieved at 160 minutes. Also, Pb(II) adsorption had followed the pseudo-first order kinetic model. Therefore, ZnO/GO is thought to be a newly promising adsorbent in removing Pb(II) ion from the aqueous solution.

Use of antiviral nanocoating in personal protective wear

The emergence of the new coronavirus and its associated fatalities are growing at an alarming rate causing unprecedented losses worldwide. As the coronavirus disease 2019 pandemic accelerates in India, access to basic personal protective wear such as masks for health-care workers and for the general public is a key concern. Aerosol transmission of biological particles such as viruses is only one of several routes of exposure for contagion of which personal protection such as masks must be used by the general public. The protection level offered by N95 and surgical masks is defined by the percent of ambient particles penetrating across the protective mask. Recent interventions in nanotechnology have effectuated need-based virus resistance masks developed by impregnating nanomaterials or nanocoatings in the mask to combat the virus and augment protection levels. The aim of this review will be to highlight the coherent strategies of using versatile nanomaterials as an effective antiviral material coated onto masks and understanding the mechanism of “virus-nanoparticle” interaction. This viricidal effect is made possible by the use of functionalized nanoparticles through the addition of biomolecule covers or modified surfaces capable of interacting with active sites present on the membrane (capsid) allowing the virus to be deactivated.

Integration of 3D nanographene into mesoporous germanium.

Graphene is a key material of interest for the modification of physicochemical surface properties. However, its flat surface is a limitation for applications requiring a high specific surface area. This restriction may be overcome by integrating 2D materials in a 3D structure. Here, a strategy for the controlled synthesis of Graphene-Mesoporous Germanium (Gr-MP-Ge) nanomaterials is presented. Bipolar electrochemical etching and chemical vapor infiltration were employed, respectively, for the nanostructuration of Ge substrate and subsequent 3D nanographene coating. While Raman spectroscopy reveals a tunable domain size of nanographene with the treatment temperature, transmission electron microscopy data confirm that the crystallinity of Gr-MP-Ge is preserved. X-ray photoelectron spectroscopy indicates the non-covalent bonding of carbon to Ge for Gr-MP-Ge. State-of-the-art molecular dynamics modeling provides a deeper understanding of the synthesis process through the presence of radicals. The successful synthesis of these nanomaterials offers the integration of nanographene into a 3D structure with a high aspect ratio and light weight, thereby opening avenues to a variety of applications for this versatile nanomaterial.

Selective synthesis of Au and graphitic carbon-encapsulated Au (Au@GC) nanoparticles by pulsed laser ablation in solvents: Catalytic Au and acid-resistant Au@GC nanoparticles

Gold nanoparticles (Au NPs) are the most versatile nanomaterials reported to date owing to their unique physiochemical properties as well as promising various applications. Recently, many techniques have been used for the synthesis of Au NPs. In this study, various types of Au NPs were synthesized by pulsed laser ablation in liquid (PLAL) using the following four solvents: methanol, deionized (DI) water, hexane, and acetonitrile. Pulsed laser ablation in methanol and DI water is used for the synthesis of bare Au NPs, as photocatalysts. Au NPs showed an enhanced catalytic activity toward the reduction of 4-nitrophenol to 4-aminophenol. Interestingly, Au NPs prepared by PLAL using hexane and acetonitrile were encapsulated with graphitic carbon (GC) layers (Au@GC), where the solvent was used as a carbon source for the GC layers. In contrast to bare Au NPs, Au@GC NPs exhibited no catalytic activity due to the protective GC layers formed on Au NPs. On the other hand, Au@GC NPs demonstrated a high corrosion resistance against strong acids. The present study revealed that the PLA of Au plate in various liquid medium is a facile method for the synthesis of excellent catalytic or acid resistant Au NPs with a unique surface structure.

Targeted Therapeutic-Immunomodulatory Nanoplatform Based on Noncrystalline Selenium.

Developing versatile nanomaterials has offered a myriad of opportunities to surmount cancer. In particular, the combination of therapy and immunomodulatory effect to further enhance immune response provides a new idea for effective tumor treatment. Herein, for the first time, an in situ growth strategy is developed to construct highly dispersed noncrystalline selenium nanoparticles (Se NPs) with thiolated cyclo(Arg-Gly-Asp-Phe-Lys-(mpa)) (RGD) peptide modification (R-Se@DMSND) for targeted cancer treatment. Se NPs could be homogeneously grown into the pore channels of dendritic mesoporous silica nanoparticles (DMSNs) since the DMSNs could stabilize Se NPs to prevent their aggregations. Moreover, Se NPs could not only act as a therapeutic agent, inducing ROS overproduction, to effectively suppress primary tumor but also as an immunomodulatory agent to simultaneously inhibit the growth of secondary tumors by enhancement of the immune response, as confirmed by the in vivo results. Such the therapeutic-immunomodulatory strategy for tumorous therapy combining with immunomodulation using one simple nanoplatform may pave a new avenue in the biomedical field.

Denatured lysozyme-coated carbon nanotubes: a versatile biohybrid material

Carbon nanotubes (CNTs) are among the most versatile nanomaterials, but their exploitation is hindered by limited dispersibility, especially in aqueous solvents. Here, we show that AP-LYS, a highly cationic soluble derivative of denatured hen egg lysozyme, is a very effective tool for the unbundling and solubilisation of CNTs. AP-LYS proved to mediate the complete and stable dispersion of CNTs at protein: CNT ratios ≥1: 3 (w:w) in very mild conditions (10–20 minutes sonication in ammonium acetate buffer, pH 5.0). Electrophoretic mobility and ζ-potential measurements confirmed that dispersed CNTs were coated by the protein, whereas molecular docking was used to study the interactions between AP-LYS and CNTs. AP-LYS-coated CNTs proved to be a very effective microbial cell-flocculating agent with an efficiency similar to that of chitosan, one of the best available flocculating agents, thus suggesting that this hybrid could find industrial applications in the treatment of wastewaters contaminated by microbial cells, or to remove microbial cells after fermentation processes. Moreover, we exploited the low stability of AP-LYS-coated CNT dispersions in eukaryotic cell culture media to prepare scaffolds with an extracellular matrix-like rough surface for the cultivation of eukaryotic cells.

Strike a balance between adsorption and catalysis capabilities in Bi2Se3−xOx composites for high-efficiency antibiotics remediation

Rational utilization of both adsorption and catalysis capabilities is an intriguing prospect in environmental remediation. Here, we demonstrate the tunability of these two capabilities in the case of bismuth selenide upon post-calcination. The temperature-related concentration of oxygen impurities in bismuth selenide gives a positive effect regarding charge separation. Meanwhile, the partial reservation of selenium is beneficial for the adsorption on antibiotics. Experimental results show that the bismuth selenide nanosheets calcinated under 180 °C exhibit the best photocatalytic performance, where the charge separation and adsorption reach an optimal equilibrium. The photocatalytic degradation efficiency reached over 90% within 120 min under simulated sunlight irradiation. The findings of this study highlight the regulation of adsorption and catalysis in environmental remediation, as well as providing new pathways to develop versatile nanomaterials for other environmental applications.