Covalent and Non-covalent Functionalized Nanomaterials for Environmental Restoration

Biofunctionalized nanomaterials for Parkinson's disease theranostics: potential for efficient PD biomarker detection and effective therapy

α-Synuclein (α-Syn) is a primary pathological indicator for Parkinson's disease (PD). The α-Syn oligomer is even more toxic and is responsible for PD. Hence, identifying α-Syn and its oligomers is an interesting approach to diagnosing PD. The prevention strategies for oligomer formation could be therapeutic in treating PD. Various conventional strategies have been developed for the management of PD. However, their clinical applications are limited due to toxicity, off-targeting, side effects, and poor bioavailability. Recently, nanomaterials have gained significant attention due to unique physicochemical characteristics such as nanoscale size, large surface area, flexibility of functionalization, and ability to protect and control a loaded payload. Functionalizing the surface of nanoparticles with a desired targeting agent could offer targeted delivery of the payload at the site of action due to specificity and selectivity against complementary molecules. Among various functionalization approaches, biomolecule-functionalized nanomaterials offer benefits such as enhanced bioavailability, improved internalization into target cells through receptor-mediated endocytosis, and delivery of therapeutics across the BBB (blood-brain barrier). In this review, we initially discussed the major milestones related to PD and highlighted the therapeutic strategies focused on clinical trials. The strategies of biomolecule functionalization of nanomaterials and their application in detecting and preventing α-Syn oligomer for the diagnosis and therapy of PD, respectively, have been reviewed comprehensively. Ultimately, we have outlined the conclusions, highlighted the limitations and challenges, and provided insight into future perspectives and alternative approaches that must be investigated.

Green procedures for synthesizing potential hNMDA receptor allosteric modulators through reduction and one-pot reductive acetylation of nitro(hetero)arenes using a superparamagnetic Fe3O4@APTMS@Cp2ZrCl x (x = 0, 1, 2) nanocatalyst

The conversion of nitro(hetero)arenes to corresponding (hetero)aryl amines and other practical organic compounds plays a crucial role in various sciences, especially environmental remediation and public health. In the current research work, diverse green and efficient strategies for the convenient reduction (hydrogenation) and one-pot two-step reductive acetylation of nitro(hetero)arenes using a core-shell-type mesoporous zirconocene-containing magnetically recoverable nanocomposite (viz. Fe3O4@APTMS@Cp2ZrCl x (x = 0, 1, 2)) as a powerful nanocatalytic system have been developed. In the presented organic transformations, the superparamagnetic Fe3O4@APTMS@Cp2ZrCl x (x = 0, 1, 2) nanocomposite exhibited satisfactory turnover numbers (TONs) and turnover frequencies (TOFs), along with acceptable reusability. On the other hand, we investigated the potential biological effect of the synthesized (hetero)aryl amines and N-(hetero)aryl acetamides against the transmembrane domain (TMD) of the human N-methyl-d-aspartate (hNMDA) receptor based on molecular docking studies. Furthermore, the drug-likeness properties of our hit compound (viz. N-(3-(1-hydroxyethyl)phenyl)acetamide) have been scrutinized by in silico ADMET analyses.

Current Advances in Aptasensors for Pesticide Detection

The increasing use of pesticides necessitates the development of innovative analytical methods to regulate environmental impacts and ensure food safety. Aptamer-based sensors hold great promise for pesticide detection owing to their superior selectivity, stability, repeatability, and regenerative capabilities. Integrated with nanomaterials, aptasensors have demonstrated enhanced sensitivity for detecting a broad range of pesticides. This study first introduces the aptamer binding mechanism and presents the fundamental concept and justification for selecting aptamer over other biorecognition molecules. It then provides a comprehensive review of recent advancements and applications of various types of aptasensors for targeted pesticide detection, including electrochemical, fluorescent, colorimetric, electrochemiluminescent, and surface-enhanced Raman scattering (SERS) aptasensors. Additionally, it offers a comparative analysis of different aptasensors by evaluating their strengths and limitations. Finally, this review discusses strategies, such as advanced Systemic Evolution of Ligands by Exponential Enrichment (SELEX) technique, self-assembled monolayers (SAMs), and the use of antifouling agents to improve the aptamer's selectivity, signal-to-noise ratio, and mitigate nonspecific adsorption challenges. These developments are essential for creating highly sensitive and selective aptasensors, facilitating their practical use in environmental monitoring and food safety.

Signalling and molecular pathways, overexpressed receptors of colorectal cancer and effective therapeutic targeting using biogenic silver nanoparticles

Increasing morbidity and mortality in CRC is a potential threat to human health. The major challenges for better treatment outcomes are the heterogeneity of CRC cases, complicated molecular pathway cross-talks, the influence of gut dysbiosis in CRC, and the lack of multimodal target-specific drug delivery. The overexpression of many receptors in CRC cells may pave the path for targeting them with multiple ligands. The design of a more target-specific drug-delivery device with multiple ligand-functionalized, green-synthesized silver nanoparticles is highly promising and may also deliver other approved chemotherapeutic agents. This review presents the various aspects of colorectal cancer and over-expressed receptors that can be targeted with appropriate ligands to enhance the specific drug delivery potency of green synthesised silver nanoparticles. This review aims to broaden further research into this multi-ligand functionalised, safer and effective silver nano drug delivery system.

Advances in smart nanotechnology-supported photodynamic therapy for cancer

Cancer has emerged as a formidable challenge in the 21st century, impacting society, public health, and the economy. Conventional cancer treatments often exhibit limited efficacy and considerable side effects, particularly in managing the advanced stages of the disease. Photodynamic therapy (PDT), a contemporary non-invasive therapeutic approach, employs photosensitizers (PS) in conjunction with precise light wavelengths to selectively target diseased tissues, inducing the generation of reactive oxygen species and ultimately leading to cancer cell apoptosis. In contrast to conventional therapies, PDT presents a lower incidence of side effects and greater precision in targeting. The integration of intelligent nanotechnology into PDT has markedly improved its effectiveness, as evidenced by the remarkable synergistic antitumor effects observed with the utilization of multifunctional nanoplatforms in conjunction with PDT. This paper provides a concise overview of the principles underlying PS and PDT, while also delving into the utilization of nanomaterial-based PDT in the context of cancer treatment.

Robust regenerable metal-selenide-chitosan photocatalyst for the effective removal of Bromothymol Blue (BB) from wastewater

Water scarcity has been a crucial debate in recent years regarding the critical scenario of water pollution. The water body is continuously contaminated by organic effluents of textile industries, including pigmented dye pollutants. To tackle water bodies contamination, there is a need to develop an eco-friendly and efficient method for removing toxic dyes. Herein, ternary metal selenide nanocomposites of barium nickel selenide (NBSe-NPs) were synthesized by the solvothermal method supported by chitosan microsphere (NBSe-NPs-CM). Recovery of the catalyst was convenient by capping nanoparticles in the microsphere to maintain effective stability, biocompatibility, and well-designed surface coating. FTIR spectrum verified nanocomposite synthesis and chitosan microsphere (NBSe-CM) formation. SEM observations of nanocomposites and NBSe-CM indicated an average size of 13.78 nm and 253 μm, respectively. The presence of barium, nickel, and selenium elements in the NBS-NPs was verified by EDX analysis. The nanocomposites had a crystallite size of 15.73 nm. The photocatalyst exhibited a narrow bandgap of only 1.3 eV based on Tauc's plot. In addition, the synthesized microsphere demonstrated an efficient photocatalytic degradation (97 %) of Bromothymol Blue dye within 100 min under optimized operating conditions (pH of 6.0, dye concentration of 40 ppm, catalyst dosage of 0.25 g). The photocatalysis process followed the pseudo-first-order kinetics. The repeatability studies showed a slight decline in the catalyst's efficiency after four successive cycles. The DFT study shows that the NBSe-CM is energetically stable with more considerable negative binding energy, and the dye molecule interacts more strongly with the NBSe-CM surface. The findings highlight the exceptional characteristics of the newly designed ternary-metal-selenide-containing chitosan-microspheres for degrading dye contaminants from textile effluents.

Carbon based nanocomposites, surface functionalization as a promising material for VOCs (volatile organic compounds) treatment

Urban residential and industrial growth development affects sustainable and healthful indoor environments. Environmental issues are a global problem. The deterioration of indoor air quality has prompted the creation of several air cleansing techniques. This review explains how carbon-based materials have influenced the development of air purification systems using photocatalysis. These carbon-based materials offer unique properties and advantages in VOC removal processes. Biochar, produced from biomass pyrolysis, provides an environmentally sustainable solution with its porous structure and carbon-rich composition. Carbon quantum dots, with their quantum confinement effects and tunable surface properties, show promise in VOC sensing and removal applications. Polymers incorporating reduced graphene oxide demonstrate enhanced adsorption capabilities owing to the synergistic effects of graphene and polymer matrices. Activated carbon fibers, characterized by their high aspect ratio and interconnected porosity, provide efficient VOC removal with rapid kinetics. With their unique electronic and structural properties, graphitic carbon nitrides offer opportunities for photocatalytic degradation of VOCs under visible light. Catalysts integrated with MXene, a two-dimensional nanomaterial, exhibit enhanced catalytic activity for VOC oxidation reactions. Using various carbon-based materials in VOC removal showcases the versatility and effectiveness of carbon-based approaches in addressing environmental challenges associated with indoor air pollution. Metal-organic-framework materials are carbon-based compounds. It examines the correlation between VOC mineralization and specific characteristics of carbon materials, including surface area, adsorption capability, surface functional groups, and optoelectronic properties. Discussions include the basics of PCO, variables influencing how well catalysts degrade, and degradation mechanisms. It explores how technology will improve in the future to advance studies on healthy and sustainable indoor air quality.

Biopolymer‑carbonaceous composites, progress, and adsorptive mitigation of water pollutants

Chitin is the second most abundant natural biopolymer, which is composed of N-acetyl glucosamine units linked by β-(1 → 4) Chitosan is an N-deacetylated product of chitin. Properties of chitosan and chitin, such as biocompatibility, non-toxic nature, and biodegradability, make them successful alternatives for energy and environmental applications. However, their low mechanical properties, small surface area, reduced thermal properties, and greater pore volume restrict the potential for adsorption applications. Multiple investigations have demonstrated that these flaws can be prevented by fabricating chitosan and chitin with carbon-based composites. This review presents a comprehensive analysis of the fabrication of chitosan/chitin carbon-based materials. Furthermore, this review examines the prevalent technologies of functionalizing chitosan/chitin biopolymers and applications of chitin and chitosan as well as chitosan/chitin carbon-based composites, in various environmental fields (mitigating diverse water contaminants and developing biosensors). Also, the subsequent regeneration and reuse of adsorbents were also discussed. Finally, we summarize a concise overview of the difficulties and potential opportunities associated with the utilization of chitosan/chitin carbon-based composites as adsorbents to remove water contaminants.

Robust polymer hybrid and assembly materials from structure tailoring to efficient catalytic remediation of emerging pollutants

A massive amount of toxic substances and harmful chemicals are released every day into the outer environment, imposing serious environmental impacts on both land and aquatic animals. To date, research is constantly in progress to determine the best catalytic material for the effective remediation of these harmful pollutants. Hybrid nanomaterials prepared by combining functional polymers with inorganic nanostructures got attention as a promising area of research owing to their remarkable multifunctional properties deriving from their entire nanocomposite structure. The versatility of the existing nanomaterials' design in polymer-inorganic hybrids, with respect to their structure, composition, and architecture, opens new prospects for catalytic applications in environmental remediation. This review article provides comprehensive detail on catalytic polymer nanocomposites and highlights how they might act as a catalyst in the remediation of toxic pollutants. Additionally, it provides a detailed clarification of the processing of design and synthetic ways for manufacturing polymer nanocomposites and explores further into the concepts of precise design methodologies. Polymer nanocomposites are used for treating pollutants (electrocatalytic, biocatalytic, catalytic, and redox degradation). The three catalytic techniques that are frequently used are thoroughly illustrated. Furthermore, significant improvements in the method through which the aforementioned catalytic process and pollutants are extensively discussed. The final section summarizes challenges in research and the potential of catalytic polymer nanocomposites for environmental remediation.

Bimetallic metal organic framework/Ni doped ZnO nanomaterials modified carbon paste electrode for selective electrochemical determination of ciprofloxacin

In this work, an efficient and sensitive electrochemical sensor for the determination of ciprofloxacin (CIP) is reported. The sensor was prepared by using a carbon paste electrode (CPE) modified with a combination of bimetallic copper/cerium-based metal organic framework (Cu/Ce-MOF) and nickel doped zinc oxide nanoparticles (NZP). The modifiers were characterized by Brunauer-Emmett-Teller (BET) analysis, Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and elemental mapping analysis (EDS). The electrochemical behavior of the modified electrode was studied by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The developed electrode was employed for the detection of CIP by differential pulse voltammetry (DPV). Under optimal conditions, the anodic peak current response of the electrode was linearly correlated with CIP concentration in the range of 0.75-100 μmol L-1 with a sensitivity of 1.29 μA μmol-1 L-1. The limit of detection and reproducibility of the method were 0.142 μmol L-1 and 2.7%, respectively. The developed sensor showed good selectivity to CIP against possible interferents. The method was applied to determine CIP in water, milk and urine samples. The results indicated that this method has potential to be applied in the analysis of residue CIP in complex matrices with high selectivity, and good reproducibility.

Metallic nanostructure-based aptasensors for robust detection of proteins

There is a significant need for fast, cost-effective, and highly sensitive protein target detection, particularly in the fields of food, environmental monitoring, and healthcare. The integration of high-affinity aptamers with metal-based nanomaterials has played a crucial role in advancing the development of innovative aptasensors tailored for the precise detection of specific proteins. Aptamers offer several advantages over commonly used molecular recognition methods, such as antibodies. Recently, a variety of metal-based aptasensors have been established. These metallic nanomaterials encompass noble metal nanoparticles, metal oxides, metal-carbon nanotubes, carbon quantum dots, graphene-conjugated metallic nanostructures, as well as their nanocomposites, metal-organic frameworks (MOFs), and MXenes. In general, these materials provide enhanced sensitivity through signal amplification and transduction mechanisms. This review primarily focuses on the advancement of aptasensors based on metallic materials for the highly sensitive detection of protein targets, including enzymes and growth factors. Additionally, it sheds light on the challenges encountered in this field and outlines future prospects. We firmly believe that this review will offer a comprehensive overview and fresh insights into metallic nanomaterials-based aptasensors and their capabilities, paving the way for the development of innovative point-of-care (POC) diagnostic devices.

Protective role of fullerenol and arginine C60 fullerene against copper toxicity in cucumber

Copper (Cu), when in excess, is one of the most toxic and hazardous metals to all living organisms, including plants. Engineered nanomaterials have the potential for increasing crop protection. However, the protective role of fullerenes (carbon-based nanoparticles with wide application in various areas) against Cu toxicity in plants is, so far, understudied. The present study investigated whether fullerenes can potentially alleviate Cu toxicity in plants (Cucumis sativus L.). Two water-soluble fullerene C60 derivatives were examined: fullerenol [C60(OH)22-24] and arginine-functionalized fullerene [C60(C6H13N4O2)8H8], under controlled conditions using hydroponics. Plants treated with 15 μM of Cu exhibited typical symptoms of Cu toxicity: impaired growth, leaf chlorosis, reduced photosynthetic activity, nutritional imbalances, and enhanced lipid peroxidation. These symptoms were alleviated in the presence of fullerene derivatives with arginine C60 having the more pronounced effect. Improved cucumber Cu tolerance was attributable to Cu buffering in the root zone (roots and medium), which caused a dramatic decline in Cu transport towards leaves and the elimination of oxidative damage. The Cu removal efficacy of arginine C60 was much greater than that of fullerenol. These fullerenes acted in a dose-dependent manner and removed Cu selectively without significant modification of the bioavailability of other essential nutrients. Treatment with free arginine did not affect Cu immobilization or Cu toxicity. These results suggest that the surface chemistry of the fullerene core is important for the protection of plants under excessive Cu conditions. The information offered a new approach to preparing promising practical materials for alleviating Cu toxicity in plants with potential application in fields.

e-Beam and γ-rays Induced Synthesis and Catalytic Properties of Copper Nanoclusters-Deposited Composite Track-Etched Membranes

Effective removal of toxic inorganic and organic pollutants is one of the current leading challenges of wastewater treatment. In this study, the decomposition of methylene blue (MB) under UV light irradiation was investigated in the presence of copper nanoclusters (NCs)-deposited polyethylene terephthalate (PET) track-etched hybrid membranes. PET track-etched membranes (TeMs) with an average pore size of ~400 nm were grafted by functional acrylic acid (AA) monomer under electron beam irradiation after oxidation with H₂O₂/UV system. The radiation dose varied between 46 and 200 kGy. For the deposition of copper NCs, poly(acrylic acid) (PAA)-grafted membranes saturated with Cu(II) ions were irradiated either by electron beam or γ-rays to obtain copper-based NCs for the catalytic degradation of MB. Irradiation to 100 kGy with accelerated electrons resulted in the formation of small and uniform copper hydroxide (Cu(OH)₂) nanoparticles homogeneously distributed over the entire volume of the template. On the other hand, irradiation under γ-rays yielded composites with copper NCs with a high degree of crystallinity. However, the size of the deposited NCs obtained by γ-irradiation was not uniform. Nanoparticles with the highest uniformity were obtained at 150 kGy dose. Detailed analysis by X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the loading of copper nanoparticles with an average size of 100 nm on the inner walls of nanochannels and on the surface of PET TeMs. Under UV light irradiation, composite membranes loaded with NCs exhibited high photocatalytic activity. It was determined that the highest catalytic activity was observed in the presence of Cu(OH)₂@PET-g-PAA membrane obtained at 250 kGy. More than 91.9% of the initial dye was degraded when this hybrid membrane was employed for 180 min, while only 83.9% of MB was degraded under UV light using Cu@PET-g-PAA membrane. Cu(OH)₂@PET-g-PAA membranes obtained under electron beam irradiation demonstrated a higher photocatalytic activity compared to Cu@PET-g-PAA membranes attained by γ-rays.

Biomimetic Electrochemical Sensors Based on Core-Shell Imprinted Polymers for Targeted Sunset Yellow Estimation in Environmental Samples

Magnetic molecularly imprinted polymers (MMIPs) contain the predesigned specialized recognition capability that can be chosen to build credible functional materials, that are easy to handle and have a good degree of specificity. Hence, the given piece of work is intended to design a novel electrochemical sensor incorporating magnetite-based molecularly imprinted polymers. The building materials consisted of a cross-linker (EGDMA), reaction-initiator (AIBN), monomer (methylene succinic acid-MSA), and template molecule (Sunset Yellow-SY dye). MMIPs exhibited a diameter of 57 nm with an irregular shape due to the presence of cavities based on SEM analysis. XRD patterns exhibited crystallinity, as well as amorphous peaks that are attributed to polymeric and non-polymeric frameworks of MMIPs. The crystallite size of the MMIPs from XRD analysis was found to be 16.28 nm based on the Debye-Scherrer's equation. Meanwhile, the FTIR bands showed the synthesis of MMIPs using monomer and methylene succinic acid. The sorption data at the optimized operating conditions (pH 2, sorbent dosage 3 mg, time 18 min) showed the highest sorption capacity of 40 mg/g. The obtained data best fitted to the Langmuir sorption isotherm and followed the pseudo-second-order kinetics. The magneto-sensors were applied for ultrasensitive, rapid, and simple sensing of SY dye. The electrochemical experiments were run at the operating condition range of (scan rate 10-50 mV/s, tads 0-120 s, pH 5-9, potential range 1-1.5 V for CV and 1-1.3 V for SWAdASV). The linear range of detection was set to 1.51 × 10^-6 M to 1.51 × 10^-6 M posing LOD and LOQ values of 8.6242 × 10^-5 M and 0.0002874 M, respectively. The regression analysis value for the calibration was found to be 0.950. Additionally, high adsorption efficiency, selectivity, reusability, and strong structural stability of the magneto-sensors showed potential use for SY detection in real samples. These characteristics make MMIPs a viable electrochemical substrate for the detection of chemical contaminants in the environment and in health-related products.

Comparison of ZnO Nanoparticles Prepared by Precipitation and Combustion for UV and Sunlight-Driven Photocatalytic Degradation of Methylene Blue

ZnO nanoparticles (NPs) were comparatively synthesized via precipitation and combustion techniques. The ZnO NPs synthesized via precipitation and combustion exhibited similar polycrystalline hexagonal wurtzite structures. The large crystal sizes of ZnO NPs were obtained from the ZnO precipitation in comparison with those from the ZnO combustion, while the particle sizes were in the same range. The functional analysis implied that the ZnO structures had surface defects. Moreover, absorbance measurement showed the same absorbance range in ultraviolet light. In the photocatalytic degradation of methylene blue, ZnO precipitation exhibited higher degradation performance than ZnO combustion. This was attributed to the larger crystal sizes of ZnO NPs, which provided an enduring carrier movement at semiconductor surfaces and reduced electron-hole recombination. Thus, the crystallinity of ZnO NPs can be considered an important factor in photocatalytic activity. Furthermore, precipitation is an interesting synthesizing method for preparing ZnO NPs with large crystal sizes.