Nanoscience & Nanotechnology-Asia - Volume 13, Issue 2, 2023

Introduction: Nanolubricants are substances that use nanoparticles as lubricant additives. The proposal for wear reduction has piqued interest in nanolubricants. Particle agglomeration is the main drawback of using nanomaterials as lubricating oil additives, and creating novel nanolubricants is one of the most difficult challenges. Objective: Evaluation of the nano β-MnO2 nanorods as nanoadditives for enhancing lubricating oil characteristics. Methods: After producing β-MnO2 nanorods by a modified hydrothermal process, oleic acid was used to modify their surfaces. Next, the physical and tribological characteristics of lubricating oil before and after the addition of nanoadditives were assessed. Results: The physical parameters of lubricating oil, including flash point, pour point, thermal stability, antiwear ability, and viscosity, were all improved by varying concentrations of surface-modified MnO2 nanorods by rates 8.19%, 50%, 63.04%, 10.9%, 8.96% at 40ºC and 4.18% at 100ºC, respectively. The findings demonstrate that the shear strain is reduced and an anti-wear boundary coating is created as a result of the deposition of nanoparticles produced by tribochemical reaction products during the friction process. Conclusion: The development of a protective film using nanoadditives improves lubricant requirements, ushering in a revolution in the lubricant industry.

Introduction: The development and applications of biological products have been seriously hindered by conventional immobilization for its low efficiency and high cost. The immobilization on solid supports for enzyme is an area of intense research due to their widespread use in synthetic chemistry and various industries. This paper highlights a great interest in the adsorption of an enzyme on the solid porous structured material and the design of new controlled delivery systems. The enzyme immobilized on solid supports and synthetic materials of the reaction mixture with strong mechanical force and easy separation serves as a high selective catalyst. Objective: A novel protein delivery system for hemoglobin (Hb) enzyme was proposed by incorporating the molecular molecules into the mesopores of well-ordered hexagonal nanometer MCM (Mobil Composition of Matters) - 41. The prepared adsorbents were successfully applied to the design and synthesis of new functionalization materials. Various parameters affecting adsorption process, such as adsorption time, adsorption isotherm, and the reusability of adsorbent, were investigated. Methods: The interaction between Hb and MCM-41 was investigated using powder X-ray diffraction (XRD), Fourier infrared spectroscopy, UV-visible solid diffuse reflectance spectroscopy and 77 K lowtemperature N2 adsorption-desorption study. Results: The experimental parameters were optimized, including the concentrations of Hb, the MCM-41 amount, and the interior surface of phenyl-functionalized Ph-MCM-41 materials. Under the optimized conditions, the biocatalytic performance was studied for Hb/MCM-41 and Hb/Ph-(MCM-41). The adsorption process of Hb by MCM-41 / Ph-(MCM-41) was in agreement with the quasi-two-order kinetic model. Process of Hb adsorption by MCM-41 / Ph-(MCM-41) belongs to an exothermic reaction, the reaction is not reversible at 4°C and it is a spontaneous reaction. The Freundlich model can better describe the adsorption of hemoglobin on MCM-41 / Ph-(MCM-41). During the desorption process of composite (MCM-41)-Hb/[Ph-(MCM-41)]-Hb in 0.1 mol/L NaOH solution, the desorption rate can reach above 70% at 2 min. At 60 min, the desorption reached equilibrium and the desorption rates were 99.58% and 91.36%, respectively. The reuse activity experimental results indicated that the immobilized enzyme exhibited high catalytic activity. Reusability stability studies suggested that the prepared composites retained their activity even after five recycling runs. This shows that the phenylation of MCM-41 reduced the "leakage" of enzyme in the main material. Conclusion: The results of the present study demonstrated that Hb/MCM-41 and Hb/Ph-(MCM-41) are highly efficient potential nanobiocatalysts for the immobilization of enzymes onto mesoporous materials.

The need for lightweight materials is increasing at a faster rate in the engineering field. It demands materials with high strength, low weight, and properties like ductility and formability which are required for easier processing of the material. When conventional pure metals and alloys failed to meet this demand, many researchers turned their attention toward developing composites. Composites can be fabricated from metal, polymer, and ceramic as base materials which are known as metal matrix composites (MMC), polymer matrix composites (PMC), and ceramic matrix composites (CMC), MMC are of special importance due to properties like strength, stiffness, and formability which are difficult to obtain from PMC and CMC. Even though conventional composites with micron-size reinforcement have enhanced certain properties like strength, hardness, and wear resistance, it deteriorated other desirable properties like ductility. To overcome these limitations of micro-composites, a new category of materials known as nanocomposite has been developed. Nano composites are materials that contain nano-scale reinforcement in different forms. This review article summarizes the recent progress in the field of metal matrix Nano composite (MMNC). Methods of fabrication which are applicable for metal alloys and micro- composites are mostly not suitable for nanocomposite fabrication, the recently developed fabrication process which are applicable for MMNC’s are discussed in this article. The effects of added nano reinforcement on the microstructure are also discussed with suitable examples. Enhancements in mechanical, tribological, and physical properties are explained in depth with the help of recently published data. Strengthening mechanisms are described with the help of empirical relations. Although industrial applications of metal matrix nano composites are limited due to the ongoing developments in this field, a few important potential application areas are also discussed at the end of this article.

In the last few years, nanozymes have emerged as an adequate substitute for natural enzymes. Recently, much attention has been paid to enzyme-mimic nanomaterials (nanozymes). Because of their distinct characteristics, they are a critical alternative to natural enzymes that can be produced at a subordinate cost and more efficiently. These nanomaterials have enzyme-like activity and have been cast off to detect and treat biomolecules such as DNA, proteins, cells, and tiny molecules such as glucose. Hence, the critical analysis of recent nanozyme is deemed essential for futuristic research, outcome-based results specified to current trends of analytical tools, and several disease monitoring for targeted oncology therapies like circulating tumor cells, MRI, PET, etc. In addition, the multivariate applications of nanozymes for biosensors, immunoassay formation, tumor cell detection with earlier remedies, and environmentallysound engineering technologies are discussed to climax the modern advancements. The novelty and originality of this current review is to intensify the recent advancement, types and mimicking activity, biomedical applications of nanozymes, implementation of the chemometric approach in nanozymes, and its futuristic approach. Finally, to promote the understanding of nanozymes and the development of novel and multifunctional nanozymes, we provide a comprehensive review of the nanozymes with their broadest applications and modern technologies involved in targeted drug delivery, inventory with other diversified arenas and existing patents indicating future implications.

Introduction: Silver nanoparticles (AgNPs) were synthesized using mangosteen pericarp ethanolic extract (MPEE) as a source of bioreductants and their antimicrobial activity against common foodborne pathogens was evaluated. Methods: Characterization of MPEE was conducted using phytochemical screening, total phenolic content analysis, and DPPH (antioxidant) assay. Synthesis AgNPs and optimization studies were monitored using UV-Vis spectrophotometry. Transmission electron microscopy was used to characterize the AgNPs, and resazurin microtiter assay was used for antimicrobial testing. Results: Alkaloids, flavonoids, saponins, quinones, anthraquinones, and tannins were confirmed present in the extract. TPC and IC50 of MPEE were 0.192 mg GAE/mg extract and 0.277 mg/mL, respectively. A surface plasmon resonance (SPR) peak within 450-403 nm confirmed the formation of AgNPs. At pH 7, the optimum reaction conditions were 45°C and 3 h. Meanwhile, at pH 9, the optimum reaction conditions were 27°C and 0.5 h. The sizes of nanoparticles synthesized at pH 7 and pH 9 were 13-35 nm and 7- 38 nm, respectively. The minimum inhibitory concentration (MIC90) of AgNPs produced at pH 7 were 1.45, 2.81, and 2.93 ug/mL for S. aureus, E.coli, and B. cereus, respectively. For AgNPs synthesized at pH 9, the MIC90 were 2.93, 3.02, and 5.24 ug/mL, for the same microorganisms, respectively. Conclusion: MPEE was able to successfully synthesize AgNPs. Compared to chloramphenicol, AgNPs exhibited better antimicrobial activity, which can address the growing concern of drug resistance in certain pathogenic microorganisms. Furthermore, the use of MPEE provides a green and sustainable alternative to synthesizing AgNPs.