Antimicrobial action of nanomaterials is typically assigned to the nanomaterial composition, size and/or shape, whereas influence of complex corona stabilizing the nanoparticle surface is often ...neglected. We demonstrate sequential surface functionalization of tyrosine-reduced gold nanoparticles (AuNPs(Tyr)) with polyoxometalates (POMs) and lysine to explore controlled chemical functionality-driven antimicrobial activity. Our investigations reveal that highly biocompatible gold nanoparticles can be tuned to be a strong antibacterial agent by fine-tuning their surface properties in a controllable manner. The observation from the antimicrobial studies on a gram negative bacterium Escherichia coli were further validated by investigating the anticancer properties of these step-wise surface-controlled materials against A549 human lung carcinoma cells, which showed a similar toxicity pattern. These studies highlight that the nanomaterial toxicity and biological applicability are strongly governed by their surface corona.
Nanozymes are defined as nanomaterials exhibiting enzyme-like properties, and they possess both catalytic functions and nanomaterial's unique physicochemical characteristics. Due to the excellent ...stability and improved catalytic activity in comparison to natural enzymes, nanozymes have established a wide base for applications in environmental pollutants monitoring and remediation. Nanozymes have been applied in the detection of heavy metal ions, molecules, and organic compounds, both quantitatively and qualitatively. Additionally, within the natural environment, nanozymes can be employed for the degradation of organic and persistent pollutants such as antibiotics, phenols, and textile dyes. Further, the potential sphere of applications for nanozymes traverses from indoor air purification to anti-biofouling agents, and even they show promise in combatting pathogenic bacteria. However, nanozymes may have inherent toxicity, which can restrict their widespread utility. Thus, it is important to evaluate and monitor the interaction and transformation of nanozymes towards biosphere damage when employed within the natural environment in a cradle-to-grave manner, to assure their utmost safety. In this context, various studies have concluded that the green synthesis of nanozymes can efficiently overcome the toxicity limitations in real life applications, and nanozymes can be well utilized in the sensing and degradation of several toxic pollutants including metal ions, pesticides, and chemical warfare agents. In this seminal review, we have explored the great potential of nanozymes, whilst addressing a range of concerns, which have often been overlooked and currently restrict widespread applications and commercialization of nanozymes.
Display omitted
•Catalase, SOD, haloperoxidase are often applied in environmental remediation.•Nanozymes are used to sense pesticides, heavy metals, and organic matters.•Nanozymes can be deployed for treating pollutants and anti-biofouling processes.•Nanozyme's toxicology profiling provides a guide for their real-life applications.
Graphene is a single-atom-thick two-dimensional carbon nanosheet with outstanding chemical, electrical, material, optical, and physical properties due to its large surface area, high electron ...mobility, thermal conductivity, and stability. These extraordinary features of graphene make it a key component for different applications in the biosensing and imaging arena. However, the use of graphene alone is correlated with certain limitations, such as irreversible self-agglomerations, less colloidal stability, poor reliability/repeatability, and non-specificity. The addition of gold nanostructures (AuNS) with graphene produces the graphene-AuNS hybrid nanocomposite which minimizes the limitations as well as providing additional synergistic properties, that is, higher effective surface area, catalytic activity, electrical conductivity, water solubility, and biocompatibility. This review focuses on the fundamental features of graphene, the multidimensional synthesis, and multipurpose applications of graphene-Au nanocomposites. The paper highlights the graphene-gold nanoparticle (AuNP) as the platform substrate for the fabrication of electrochemical and surface-enhanced Raman scattering (SERS)-based biosensors in diverse applications as well as SERS-directed bio-imaging, which is considered as an emerging sector for monitoring stem cell differentiation, and detection and treatment of cancer.
Single and Two Stage Anaerobic Digestion of landfill leachate.
Display omitted
•Assessment of Single and two stage AD of leachate with varying pH and IOL.•Highest VFA yield was obtained at IOL of ...48 g/L at acidic (5.5) & alkaline (11) pH.•Acetic acid was dominant at acidic pH whereas it was butyric acid at alkaline pH.•IOL of 48 g/L and 6 g/L yielded highest methane in single & two stage respectively.•Overall increase of 21% COD removal efficiency can be achieved in two stage AD.
This work aims to evaluate the impact of pH and initial organic load (IOL) in terms of Chemical Oxygen Demand (COD) of landfill leachate for the production of value added products during single and two stage anaerobic digestion (AD). It was observed that at an optimal IOL of 48 g/L, acetic acid was dominant at pH 5.5 whereas it was butyric acid at pH of 5.5–6.0 and 10–11. The yield of Volatile Fatty Acids (VFA) was dependent on IOL and it was in the range of 0.26 to 0.36 g VFA/(g COD removed). Methane was also harvested during single and two stage AD and found that it was varying in the range of 0.21–0.34 L CH4/(g COD removed) and 0.2–0.32 L CH4/(g COD removed) respectively. An overall increase of 21% COD removal was noticed in two stage AD in comparison to single stage.
Mercury pollution threatens the environment and human health across the globe. This neurotoxic substance is encountered in artisanal gold mining, coal combustion, oil and gas refining, waste ...incineration, chloralkali plant operation, metallurgy, and areas of agriculture in which mercury‐rich fungicides are used. Thousands of tonnes of mercury are emitted annually through these activities. With the Minamata Convention on Mercury entering force this year, increasing regulation of mercury pollution is imminent. It is therefore critical to provide inexpensive and scalable mercury sorbents. The research herein addresses this need by introducing low‐cost mercury sorbents made solely from sulfur and unsaturated cooking oils. A porous version of the polymer was prepared by simply synthesising the polymer in the presence of a sodium chloride porogen. The resulting material is a rubber that captures liquid mercury metal, mercury vapour, inorganic mercury bound to organic matter, and highly toxic alkylmercury compounds. Mercury removal from air, water and soil was demonstrated. Because sulfur is a by‐product of petroleum refining and spent cooking oils from the food industry are suitable starting materials, these mercury‐capturing polymers can be synthesised entirely from waste and supplied on multi‐kilogram scales. This study is therefore an advance in waste valorisation and environmental chemistry.
Laying waste to mercury pollution: A sustainable rubber made from sulfur and recycled cooking oil is a general sorbent for diverse forms of mercury pollution.
Display omitted
•A non-noble metal catalyst is reported for aqueous LA hydrogenation to GVL.•All the reactions are carried out in the vapour phase at atmospheric pressure.•A reaction pathway is ...proposed for this reaction based on experimental data.•Lewis acid sites are found to be responsible for the conversion of levulinic acid.
The TiO2 supported Ni catalysts were investigated for vapour phase hydrogenation of aqueous levulinic acid at ambient pressure. Ni/TiO2 demonstrated high selectivity of γ-valerolactone (GVL) compared to noble metal (Pt, Pd, Ru) catalysts. The surface acid sites played an important role on the product distribution. Pyridine adsorbed DRIFT spectra revealed that the Lewis acid sites on Ni/TiO2 were responsible for high selectivity of γ-valerolactone. In contrast, the Brønsted acid sites are prone to ring opening of γ-valerolactone to produce valeric acid and hydrocarbons. The physicochemical characteristics of Ni/TiO2 were correlated with γ-valerolactone rates. Based on the kinetic study a mechanism has been proposed.
Display omitted
•A 2-step process is used to synthesize nano oxides integrated ZSM-5 catalysts.•82% yield of integrated ZSM-5 catalysts is possible at low temperature and pressure.•59% yield of ...biogasoline is possible thorough catalytic cracking process.
Biofuels produced from palm oil have shown great potential as a useful fossil fuel substitute and are environmental friendly. Utilization of palm oil as biofuel requires zeolite based catalytic technology that facilitates selective conversion of substrates to desired products, including biogasoline and biodiesel. However, the synthesis and integration of suitable zeolite based supported catalysts for the desired products are the key challenges in biofuel production. The alternative to overcome these problems is to use nano heterometallic materials supported on zeolite catalysts. In this study, Zeolite Socony Mobile-5 (ZSM-5) based catalysts loaded with heterometallic nano oxides were synthesized. Next, the catalysts used for the palm oil cracking to produce biogasoline were characterized by field emission electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR) and Brunauer, Emmett and Teller (BET) analysis. Taguchi method was used to assess and optimize the catalytic cracking process. The catalytic cracking results illustrated that under optimized conditions, ZSM-5 (30), Fe–Zn–Cu–ZSM-5 (31), Fe–Zn–Cu–ZSM-5 (32) and Fe–Zn–ZSM-5 (33) yielded 14%, 59%, 49% and 56% biogasoline, respectively. Higher efficiency of Fe–Zn–Cu–ZSM-5 (31) might be attributed to higher content of loaded metal oxides as compared to the other synthesized catalysts. The yield of biogasoline in this study, catalyzed by Fe–Zn–Cu–ZSM-5 (31), was 8% more than the literature values. Therefore, the present study proved that the newly developed Fe–Zn–Cu–ZSM-5 (31) was an efficient and economical catalyst for producing biogasoline from cracking of palm oil.
The prevalence of 3D-printed portable biomedical sensing devices, which are fashioned mainly from plastic and polymer materials, introduces a pressing concern due to their limited reusability and ...consequential generation of substantial disposable waste. Considering this, herein, we pioneered a ground-breaking advancement,
, a 3D-printed metal substrate-based enzyme. Our inventive methodology involved the synthesis of a thermally degraded Fe-based metal-organic framework, DEG 500, followed by its deposition on a 3D-printed metal substrate composed of Ti-Al-V alloy. This novel composite exhibited remarkable peroxidase-like activity in a range of different temperatures and pH, coupled with the ability to detect glucose in real-world samples such as blood and fruit juices. The exceptional enzymatic behaviour was attributed to the diverse iron (Fe) oxidation states and the presence of oxygen vacancies, as evidenced through advanced characterization techniques. Fundamentally, we rigorously explored the mechanistic pathway through controlled studies and theoretical calculations, culminating in a transformative stride toward more sustainable and effective biomedical sensing practices.
We illustrate a new strategy to improve the antibacterial potential of silver nanoparticles (AgNPs) by their surface modification with the surface corona of biologically active polyoxometalates ...(POMs). The stable POM surface corona was achieved by utilising zwitterionic tyrosine amino acid as a pH-switchable reducing and capping agent of AgNPs. The general applicability of this approach was demonstrated by developing surface coronas of phosphotungstic acid (PTA) and phosphomolybdic acid (PMA) around AgNPs. Our investigations on Gram negative bacterium Escherichia coli demonstrate that in conjugation with AgNPs, the surface corona of POMs enhances the physical damage to the bacterial cells due to synergistic antibacterial action of AgNPs and POMs, and the ability of tyrosine-reduced AgNPs (AgNPs(Y)) to act as an excellent carrier and stabiliser for the POMs. The further extension of this study towards Gram positive bacterium Staphylococcus albus showed a similar toxicity pattern, whereas these nanomaterials were found to be biocompatible for PC3 epithelial mammalian cells, suggesting the potential of these materials towards specific antimicrobial targeting for topical wound healing applications. The outcomes of this work show that facile tailorability of nanostructured surfaces may play a considerable role in controlling the biological activities of different nanomaterials.
PDF
