Malaysian NANO-An International Journal (MNIJ)
Malaysian NANO-An International Journal (MNIJ) offers a multidisciplinary source of information on all subjects and topics related to Nanoscience and Nanotechnology. MNIJ aims to offer researchers, academics, students and interested individuals worldwide an opportunity to get informed of the latest advancements in Nanoscience and Nanotechnology. Special issues are regularly devoted to research and development of nanotechnology in individual countries and on specific topics. The articles featured in special issues for MNIJ are by invitation only. MNIJ is an international peer-reviewed open-access journal, a multi-disciplinary journal twice yearly published by the Nanotechnology & Catalysis Research Centre, University of Malaya, Malaysia. eISSN : 2805-5152 Publisher : Nanotechnology and Catalysis Research Centre (NANOCAT) Publication frequency : 2 time(s) per year Fee : No fee charges
Nanotechnology and Catalysis Research Centre (NANOCAT)
Recent Advances in Biological Nanodevices and Biosensors: Insights into Applications and Technological Innovations
This paper explores recent advances in the detection of viruses and metals, focusing on how biosensors are revolutionizing environmental management and healthcare. Biosensors have transformed fields such as medical diagnostics by enabling the detection of biological targets at low concentrations. Specifically, graphene field-effect transistor (FET)-based immunosensors have emerged as powerful tools for swiftly and accurately identifying biological targets, opening new avenues in these areas. Furthermore, improvements in metal detection have enabled the monitoring of electrical activity in non-excitable cells, advancing research into cancer bioelectricity and its therapeutic applications. These advancements demonstrate how nanotechnology can innovate approaches in healthcare, offering more sensitive, adaptable, and efficient methods. Additionally, progress in cellular electrophysiology holds promise for enhancing treatments in neurology, cardiology, and regenerative medicine. These advancements can lead to better patient outcomes and expedite the development of bioengineered tissues and organs with integrated electrical properties. This paper explores these groundbreaking applications of biosensors in environmental and medical sciences, highlighting their transformative potential and future directions.
Copyright (c) 2024 Malaysian NANO-An International Journal
Comprehensive review on graphene, its synthesis, properties and applications in drug delivery
Graphene, a single layer of carbon atoms arranged in a two-dimensional honeycomb lattice, has garnered significant attention for its exceptional properties and versatile applications. This comprehensive review delves into the synthesis, properties, and burgeoning applications of graphene in drug delivery systems. We explore various synthesis methods, including mechanical exfoliation, chemical vapour deposition, and reduction of graphene oxide, highlighting their advantages and limitations. The review discusses graphene's remarkable mechanical strength, electrical conductivity, thermal stability, and large surface area, which contribute to its efficacy as a drug delivery platform. Furthermore, we examine the biocompatibility and functionalization strategies that enable targeted and controlled drug release. Applications in cancer therapy, gene delivery, and tissue engineering are scrutinized, demonstrating graphene's potential to revolutionize these fields. Challenges such as toxicity, scalability, and regulatory considerations are also addressed, providing a balanced perspective on the future of graphene in biomedical applications. This review aims to provide a comprehensive understanding of graphene's role in drug delivery, paving the way for further research and development in this promising area.
Role of nanomaterials in food authentication techniques: A mini-review
Food authentication is critical for ensuring food safety, quality, and compliance with regulatory standards. The growing complexity of food supply chains and increasing incidents of food fraud necessitate advanced and reliable methods for verifying food authenticity. Nanomaterials (NMs) have emerged as powerful tools in food authentication due to their unique physicochemical properties. This mini-review explores the application of various NMs, including metal nanoparticles (NPs), carbon-based NMs, and quantum dots, in the detection and identification of food adulteration and contamination. The review highlights recent advancements, practical applications, and future prospects of NMs in enhancing food authentication techniques. In this review, we explore the latest advancements in the application of NMs in food analysis. We summarize recent developments in NP usage for detecting contaminants in food and highlight the prospects and future directions for creating dependable devices for authentic analysis.
Synthesis of PMMA-PEG@TiO2 nanocomposite by hydrothermal and sol-gel techniques for resveratrol delivery
TiO2 nanoparticles were prepared using the sol-gel and hydrothermal procedures in order to compare their porosity, stability, and particle homogeneity as well as their encapsulation efficiency. Alcohol is converted into gel using the sol-gel method, which involves stirring it while it's hot, then drying, powdering, and calcining it. This simple process produces high-purity products, however due to agglomeration, it also produces unpredictable particle size and shape. On the other hand, hydrothermal approach requires enormous volumes at high pressure, which makes it slow and difficult to scale up. However, it is effective in producing uniform nanoparticles. Nanoparticles were synthesized using both methods to evaluate differences in drug loading and releasing capacities. TiO2 was chosen for its excellent biocompatibility, mechanical strength, and chemical resistance, as well as its documented anticancer activity. To prevent premature drug release, the TiO2 nanoparticles were coated with a copolymer of Poly(methyl methacrylate) and Polyethylene glycol (PMMA-PEG), which forms a mesh-like structure that enhances drug absorption and loading capacity. The drug Resveratrol was used in this study. The synthesized nanoparticles were characterized using X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), and scanning electron microscopy (SEM) to analyze their structural and morphological properties. These characterization results facilitated the determination of the most effective synthesis method for creating TiO2 nanoparticles with superior anticancer activity.
Employing carbon nanocomposites for the removal of hazardous contaminants from aqueous solution
Carbon nanocomposites have captured the curiosity of catalysis research and adsorption studies owing to their extremely small dimensions and shape-dependent chemical and physical properties. Metal nanomaterials and materials made of carbon, including graphene and carbon nanotube-based nanocomposites, displayed exceptional catalytic properties in organic chemical reactions. Carbon nanocomposites made from biomass are a low-cost, developing, and attractive technology for the production of surface-enhanced nanocomposites. For the elimination of all harmful pollutants, including dyes, heavy metals, emerging contaminants, and persistent organic contaminants, -based nanocomposites are utilised. As a result, the demand for carbon nanocomposites has been rising quickly, and the creation of new methods for preparing them deserves particular attention. This short review gives a comprehensive overview of several hazardous substances and their effects on the environment. Additionally, it examines the production, uses, and types of carbon nanocomposites as well as new developments in their capacity to remove organic contaminants from wastewater. In order to simultaneously remove contaminants from industrial effluent and advance the aims of environmentally friendly growth, future research is required. It's important to find an affordable technique to use carbon nanocomposites in wastewater treatment in large scale.
Advancements in biomimetic nanomaterials in the activation of NFκb receptors in cancer
Biomimetic nanomaterials are catching up in the field of oncology with the traditional methods of treating cancer. One of the main causes of cancer is the misregulation of NF-κB receptors in the body. They are essential for the DNA transcription, cytokine synthesis and cell survival. This study includes the roles of different biomimetic particles involved in the activation of NF-kB pathway that leads to cancer. Nuclear factor-kB (NF-kB) transcription factors are involved in a variety of physiological processes, including innate and adaptive immunological responses, cell proliferation, cell death, and inflammation. It has been established that abnormal regulation of NF-kB and the signalling pathways that govern its activity play a role in cancer formation and development, as well as tolerance to chemo- and radiotherapy. Future treatment options in nanotech. for the treatment of cancer includes the conjugation of nanoparticles and antibodies in order to supress the activation of NF-kB receptor and the use of carbon-based nanomaterial like graphene.
Nanotechnology in agriculture: A review of innovative utilization
The escalating challenges posed by swift population growth, global climate change, and occurrences of disease outbreaks to ensure food security necessitate innovate agricultural improvement techniques. In this intricate milieu, nanotechnology, with its remarkable advancements, emerges as a potent avenue for enhancing sustainable agricultural practices. This review underscores the current landscape of nanotechnology in agriculture, highlighting the classification and synthesis of nanomaterials. Furthermore, insightful applications of nano-based products in agriculture are meticulously elucidated in term of advantages and risks possessed. Notably, the regulatory frameworks from different countries have been addressed to ensure the safety of consumers and the environment. However, despite its myriad benefits, nanotechnology is not exempt from limitations and potential negative consequences, which are explored in the final section of this review. Keywords: nanomaterials, agriculture, nano-based products, regulatory frameworks
Green synthesis of size-controlled silver nan particles and their anti-cancer potentiality
Silver nanoparticles (Ag-NPs) are now well recognized as one of the most prevalent kinds of materials that are put to use in a wide variety of biomedical applications, most notably as an anti-cancer agent. In the current investigation, Ag-NPs were effectively produced by reducing silver ions by employing the leaf extract of Artocarpus heterophyllus as a source of reducing and capping agents. By altering the quantity of the silver nitrate solution, we successfully synthesized three distinct kinds of Ag-nanoparticles that were mediated by Artocarpus heterophyllus leaf extract. The X-ray diffraction (XRD) analysis first confirmed the formation of metallic silver, where peaks were found at fixed angles. XRD method was also used to validate the crystal geometry of the Ag-NPs, revealing that the Ag-NPs had a face-cantered cubic structure. The calculated average crystallite sizes of Sample-1 Ag-NPs, Sample-2 Ag-NPs, and Sample-3 Ag-NPs were 20.34 nm, 16.99 nm, and 18.88 nm, respectively. Ag-NPs were also confirmed from EDX analysis and firm Ag peaks, including several organic compound peaks. The nanoparticle’s range was between 120 nm and 220 nm, and the average particle size was near 170 nm, as found in the SEM image, and accumulation was observed in the SEM image. Using Fourier Transform Infrared (FT-IR) spectroscopy, we determined the functional groups of organic compounds that might be responsible for reducing agents and the presence of capping agents on the surface of Ag-NPs. The cell viability test was used to assess the cytotoxicity using the HeLa cell, a human carcinoma cell. The results revealed that the produced Ag-NPs demonstrated toxicity against carcinoma cells.
Gold nanoparticles supported on reduced graphene oxide as green catalyst for solventless hydrosilylation process
The hydrosilylation reaction is a versatile process that is used to synthesize a variety of organosilicon compounds. However, the traditional metal oxide catalysts used for this reaction suffer from low activity and selectivity. In this study, we synthesized and characterized a gold nanoparticles (AuNPs)-reduced graphene oxide (rGO) catalyst for the hydrosilylation reaction. The AuNPs-rGO catalyst was synthesized by a one-pot method using trisodium citrate (Na3C6H5O7) as a reducing and capping agent. The catalyst was characterized by XRD, FESEM, and FTIR. The hydrosilylation reaction was carried out under solventless conditions using dimethylphenylsilane as the substrate. The AuNPs-rGO catalyst was found to be highly active and selective for the hydrosilylation reaction, yielding a 100% conversion of the substrate to disiloxane in 3 hours. The results of this study demonstrate the potential of AuNPs-rGO catalysts for the hydrosilylation reaction and suggest that they could be used to develop more efficient and sustainable processes for the synthesis of organosilicon compounds.
Investigation on impact properties of basalt and glass fiber reinforced polyester composites filled with nano silica
The relevance of granite waste is growing alongside the global demand for granite. This waste comprises various forms, including large granite pieces, tiny fragments, dust, and other debris. This research aimed to create a novel composite by incorporating nano silica from granite powder as a filler, combining it with basalt and glass fibres as the matrix, and using polyester as the resin. The fabrication involved Fiber Reinforced Composite (FRP) production through hand lay-up and vacuum silicon moulding to eliminate trapped air during lamination. After fabrication, tests were conducted for hardness, density, and Low-Velocity Impact under dropping weight. The results indicated that introducing nano silica as a filler in polyester resin positively impacted Basalt Fiber Reinforced Polyester Composite (BFRPC) and Glass Fiber Reinforced Polyester Composite (GFRPC). Analysis showed that as the nano-silica content increased, so did energy absorbed, impact strength and ductility index, up to a 1wt% nano-silica concentration. Beyond this point, agglomeration occurred, causing a decrease in these values. The 1 Nano silica Basalt Fiber Reinforced Polyester Composite (1NSBFRPC) material exhibited the highest energy absorption at 103.21J, indicating strong impact strength at 21.27kJ/m2. Conversely, the 1NSGFRPC material demonstrated the highest ductility index at 4.13. In comparison, Carbon Tech Global's (CTG) energy absorption, initially 25.56J, experienced a significant increase of 303.79%, reaching 103.21J. The impact strength also showed a notable shift, escalating by 396.96% from 4.28 KJ/m2 to an impressive 21.27kJ/m2. This shift in impact strength represented a remarkable 128.2% surge, highlighting the significant influence of integrating nano-silica. This new composite suits truck body carriers and offers environmental benefits. Furthermore, utilising nano silica in this context not only aids in waste reduction within the granite sector but also contributes to sustainable resources.
Multilayered nano Ti3C2Tx electrode: An ultrasensitive electrochemical sensor for rutin antioxidant detection
Multilayer two-dimensional (2D) structures (MXenes) provide promising advantages in biomedical applications. Using SEM and XRD characterization techniques, the synthesized substance was identified. Our results show that Ti3C2Tx-GCE possesses a significant number of active sites, enhancing its electrocatalytic activity and electrochemical sensing abilities for RT oxidation. The multilayered Ti3C2Tx-GCE that was produced had good electrochemical properties and acceptable pore structures. Additionally, it exhibited remarkable linearity starting from 1 to 10 μM and demonstrated high sensitivity for the electrochemical measurement of RT, with an impressively low limit of detection (LOD) of 0.345 μM. EIS studies revealed that the synthesized multilayered Ti3C2Tx possessed a significantly low charge transfer resistance and a high electron transfer rate constant. Our research lays the groundwork for designing a multilayered Ti3C2Tx network, which opens up intriguing possibilities for creating high-performance electrochemical sensors for use in biomedicine and clinical settings.
Copyright (c) 2023 Malaysian NANO-An International Journal
Investigation of energy storage applications on nickel fluoride nanomaterials under shock wave flow environments
In this research article, we have conducted the comparative studies on ambient and 200 shock loaded NiF2 sample using a table top pressure-driven shock tube (Reddy Tube) for supercapacitor application. The stability of structural, morphological and electrochemical properties of the shock loaded and unloaded were tested and analysed. The shock wave of 2.2 Mach number with transient pressure of 2.0 MPa with 864 K temperature was made to strike on two test samples (ambient and 200). The molecular and crystallite structure stabilities of the test samples were examined by XRD and FTIR. The surface morphology was investigated by FESEM and electrochemical measurements such as Cyclic Voltammetry (CV), Galvanostatic Charge-Discharge (GCD) techniques were performed to investigate the super capacitive behaviour of NiF2 sample for loaded and unloaded conditions. The obtained results revealed changes in crystallite size and particle size and it still maintains its phase stability of rutile NiF2 after 200 shocked conditions. Further, the electrochemical measurements exhibit higher capacitance of 1770.5 F/g for 200 shock loaded condition which is very high range when compared with ambient condition. Furthermore, it measured high energy density (88.52 Wh/kg) and power density (1499.8 W/kg) at 2 A/g current density which is very higher compared to others. Hence under high shocked conditions, the electrochemical properties were enhanced due to shock wave impacts on the NiF2 material.
Synthesis and characterization of nanoscale level mono/bi-ligated metal(II) complexes
A series of nanoscale level metal complexes with bidentate (N2MCl2) and tetradentate (MN) chromophores as cisplatin analogues and intercalating agents of, [M(phen)Cl2] (1- 3), [M(bpy)Cl2] (4-6), [M(phen)2] (7-9) and [M(bpy)2] (10-12) (where respectively M = Cu(II), Ni(II) or Zn(II); phen = 1,10-phenanthroline and bpy = 2,2’-bipyridine) respectively were prepared in the present investigation. These complexes were prepared by sonochemical technique and characterized using elemental, spectral, and electrochemical techniques. Their nanorod or stick morphologies and crystalline nature were evaluated with scanning electron microscopy (SEM). Metal complexes, 1-6 are existing with two labile chlorides similar to the chemotherapeutic inorganic drug cisplatin, which may anticipate binding covalently with herring sperm DNA, While, complexes, 7-12 may undergo an intercalative mode of binding due to their structural differences relative to 1-6.
Nanocellulose-based carbon nanocomposite for the electrochemical sensing application for pharmaceuticals: A review
Biopolymers are naturally occurring polymers which have attained profound interest and are investigated widely due to their outstanding characteristics and several advantages such as cost efficiency, hydrophilicity, film formation capability, chemical inertness, non-toxicity, high mechanical integrity and biocompatibility. Cellulose is the most abundant biopolymer in the world. Nanocellulose (NC) is a cost-efficient, biodegradable, eco-friendly, biocompatible and abundant, renewable biomaterial obtained from cellulose by nanoscale isolation. The most interesting property of NC as the precursor material, is that it does not possess hierarchical structural defect. Recently, the incorporation of NC into electroconductive platforms i.e., nanostructured carbon nanocomposite is a hot topic for researchers. NC is not an electroconductive material but an ionic conductor. Availing this property NC can be incorporated with carbon-based materials. CNTs is a carbon-based material with excellent electronic properties, high electroconductive and mechanical properties. This review focuses on the application of nanocomposites containing NC and carbon nanostructured especially CNTs and their properties and sensing applications.
Preparation and analysis of activated carbon from pomegranate peel for battery applications
Currently, natural nontoxic carbon in energy storage systems has attracted much attention because of its scalability, low cost, and microspore nature. Activated carbon has a network of interconnected micro-and mesopores. As a result, the carbon material has a large amount of porosity and specific surface area. The pomegranate peel and activation agent significantly affected the surface area and pore structure. Therefore, a pomegranate peel carbon (PPC) anode material was prepared using a hydrothermal method. The effective carbonization of the pomegranate peel was investigated using scanning electron microscopy. Electrochemical measurements were performed using cycle voltammetry. Powder X-ray diffraction (XRD) analysis was used to investigate the nature of the sample. Scanning electron microscopy (SEM) was used to characterize the morphology of the prepared activated carbon.
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Synthesis and characterization of magnesium hydroxide nanoparticles via sol-gel
The magnesium hydroxide (Mg (OH)2 nanoparticles (NPs) were prepared using the sol-gel method and presented its results in this work. Various characterization methods have been used to confirm the successful preparation of Mg (OH)2 NPs. The XRD analysis exhibited the hexagonal structure of the sample. FT-IR spectrum revealed the presence of metal-oxygen stretching of prepared magnesium hydroxide NPs. The SEM analysis shows that the synthesized Mg (OH)2 NPs were clustered with a rough stacked surface. From the absorption peak obtained through UV-Vis spectroscopy, the bandgap energy of Mg (OH)2 NPs was calculated as 2.70 eV.
Solvothermal synthesis and characterization of Iron oxide nanoparticles
In the present study, we investigated the crystallinity, surface morphology, and optical properties of iron oxide (Fe3O4) nanoparticles (NPs) formed by solvothermal synthesis. From powder XRD analysis, the Fe3O4 NPs were found to be an inverse spinel structure and highly crystalline nature. The surface morphology and particle size distribution were analyzed using a scanning electron microscope (SEM). The elemental compositions were confirmed using energy-dispersive X-ray spectroscopy (EDX). The optical characteristics of the Fe3O4 NPs were analyzed by UV-Vis spectroscopy. Overall, from the analysis, Fe3O4 NPs with tailored optical and structural properties can be easily formed by the solvothermal route to find potential applications in industries and the medical field.
Synthesis of ammonium oxonium dodeca-molybdophosphate nanostructures for supercapacitor application
Supercapacitors and ultracapacitors are considered potential candidates in the field of energy storage devices for future generations. In this work, Ammonium oxonium dodeca-molybdophosphate nanospheres were successfully prepared using the co-precipitation method. The XRD pattern confirms that the material has a cubic crystal structure. The functional groups of the nanoparticles were analyzed using FTIR spectroscopy. The optical properties were studied using UV absorption spectroscopy. SEM images were used to confirm the morphological variations of the materials. CV and charge/discharge studies were conducted to investigate the electrochemical performance of the nanospheres.
Tailoring the size and magnetic property of biogenic silver nanoparticles
By exploring biological sources, the area of nanotechnology is currently thriving and offers a fresh method. Plant extract-mediated green nanomaterial synthesis has gained appeal as a result of its cost-effectiveness and environmentally beneficial characteristics. In this study, Ag NPs were successfully synthesized from reducing Ag+ ions using Mangifera indica leaf extracts as a source of reducing and capping agents. Several different microscopic and spectroscopic approaches were used in order to characterize the produced Ag NPs. Analyses using XRD and SEM have been carried out to look into the morphology of the generated Ag NPs. The (XRD) pattern peaks are associated with the metallic silver in the (FCC) shape. Silver nanoparticles average grain size is in the 10–100 nm range for all concentrations of AgNO3. The shape of the produced silver nanoparticles was determined to be round and spherical by (SEM), and their total size was determined to be between 50 and 100 nm. Analysis using EDX spectroscopy also demonstrated the production of silver and the presence of components that performed the function of a capping agent. (FT-IR) spectra were performed in order to determine the organic groups like carbonyl, hydroxyl, amine, and protein molecules. Analysis using (FT-IR) spectroscopy publicized the presence of flavonoids, polyphenols, and amide groups, all of which are candidates for being responsible for the environmentally friendly creation of silver nanoparticles. From (VSM) analysis, the biosynthesized Ag NPs were weak ferromagnetic in nature, which would be a potential research arena, especially for device application and medical equipment construction using these magnetic crystalline AgNPs. Keywords: Ag NPs, synthesized, X-ray Diffraction, TGA, magnetization
A Critical Review of Nanomaterials and Their Industrial Applications
The innovative and universal nature of nanotechnology has extensively driven the interest of scientists for the past few decades. Besides its utilization in several sectors such as pharmaceuticals & drug development, with highly funded government projects to develop a wide range of nanotech-based products, its commercialism is still comparatively poor. Although these technologies enable to resolve the issues with drugs in the pharmaceutical industry, especially reformulating the drugs to improvise their physicochemical properties & the level of toxicity (including the rate of dissolution, bioaccumulation & its toxicological nature compared to the standards recorded in scientific reports. Depending on the experience gained from decades of nanotechnology-derived drug delivery systems and an extensive literature review, it was determined that the main reason for commercialization failure was listed as follows a) insufficient regulative framework system; b) poorly accepted & supported by the consumers (the public), doctors in practice & industries; c) manufacturing criteria including the capability for large-scale production, characterization, quality control, and suitable translation; 4) issues with toxicity, ecological hazardous & safety profiles; 5) inadequate interdisciplinary platforms; and, 6) Lack of IPR (Intellectual property rights) protection. This present review elaborates on the key issues & the trends followed in the industries, the Regulatory role of the USFDA with implications, and the challenges set forth for the successful translation of nanotech-based products from the laboratory to the market.
The synergistic effect of N-doped TiO2-SiO2 nanocatalysts and peroxydisulfate towards improving Bisphenol A photodegradation efficiency
TiO2-based photocatalysts have attracted tremendous attention for the degradation of hazardous organic pollutants in sewage. In this work, a series of N-doped TiO2-SiO2 with varying N contents (10N-TS5, 20N- TS5, 30N-TS5) were successfully synthesized via sol-gel method. The physical properties of the catalyst are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive emission spectroscopy (EDX), UV-visible absorption spectroscopy, and specific surface area (BET) measurements. The photocatalytic activities of as-prepared catalysts were assessed by degrading 10 mg. L-1 Bisphenol A (BPA) under simulated natural light irradiation. The results indicate that the N doping in the TiO2-SiO2 nanostructures can reduce the crystal sizes, improve the BET surface areas, and narrow the band gap energy, thereby enhancing the photocatalytic activity of the materials. The 10N-TS5 exhibits the best photoactivity, which degrades 90.7 % of BPA for 240 min irradiation. Noteworthy, the presence of 2 mM peroxydisulfate (PDS, S2O82-) in the 10N-TS5 reaction system removes completely 10ppm BPA for only 50 min illumination with the rate constant of 10.9×10-2 min-1, 7.8 times higher than that of 10N-TS5 suspension without PDS agent. The N-doped TiO2-SiO2 photocatalyst coupling with PDS provides a promising pathway for environmental remediation.
Applications of nanocellulose as biosensing platforms for the detection of functional biomacromolecules: A Review
Cellulose is a group of materials that can be made into low-cost devices because they are the most common biomaterials in nature. Cellulose-based polymers are flexible, biocompatible, biodegradable, and easy to functionalise and mass produce. Cellulosic substrates are attractive biosensing platforms because of their unique properties, exceptional simplicity, and compatibility with standard technologies. Furthermore, cellulose-based biosensing approaches can meet the following criteria for optimal diagnostic assays or devices: real-time connectivity; simplicity of specimen collection; affordability; specificity; sensitivity; user-friendliness; speed and robustness; and deliverability to end-users. As a result, cellulose is suitable for constructing novel analytical devices in the biosensing community. The use of cellulose as a nano-engineered matrix material has enabled recent advancements in biosensors. Several methodologies for producing cellulose-based composites for the fabrication of various biosensors have been described and reviewed. Biological macromolecules have immense importance in genetic and pathogenicity detection. Likewise, there are many research reports, but there is a gap regarding review in this area of biological macromolecule detection like nucleic acids and proteins. This study looked at this previously unexplored area as well as the unique features that make it a good choice for biosensing applications and the engineering features of cellulose-based biosensors. It also looked at how different analytical systems have used such matrices to detect biological macromolecules (DNA, proteins, and RNA) in different samples.
In this study, zinc oxide (ZnO) structured films were grown on glass substrates using a simple chemical bath deposition (CBD) method with different salt precursors. The variation of salt precursors towards the surface morphology of thin films and its wettability properties were investigated. Four types of zinc (Zn) salt used as precursors are zinc chloride (ZnCl2), zinc acetate (ZnAc2), zinc nitrate (Zn(NO3)2) and zinc sulfate (ZnSO4). The crystallinity of ZnO thin films was evaluated using X-ray diffraction (XRD), and the surface morphology was observed using field emission scanning electron microscopy (FESEM). Finally, the wettability was determined by contact angle (CA) measurement. It was found that ZnCl2 has the lowest CA (127.1°), while ZnSO4 exhibits the highest CA (142.3°). The Zn salts used significantly influenced the thin film surface morphology, resulting in varied wetting behaviour depending on the surface roughness.
Marangoni Convection in a Wavy Trapezoidal Enclosure with Different Amplitudes
In this paper, Marangoni convection inside a trapezoidal enclosure with nanofluid is numerically studied for different amplitudes. One side of the cavity is heated while the other is cooled with natural convection taking place at the top wall. The fluid flow and heat transfer are investigated at different amplitudes, particle volume fractions, Rayleigh and Marangoni numbers. The results are then shown in the form of streamlines, isotherms, local Nusselt and average Nusselt numbers. It was discovered that increasing the amplitude of the heated wavy wall improved heat transfer significantly, though the strength of fluid flow diminishes slightly.
Sharifah Nuriza Syed Muhammad Naquib Al'Aidrus
Fabrication and characterization of single and bimetallic non-alloyed nanoparticles
We have demonstrated the fabrication of single and bimetallic Au and Ag nanoparticles on SiO2 substrate for light trapping application. Those nanoparticles were obtained by depositing 6nm and 8nm Au while 8nm and 10nm of Ag on SiO2 substrate. Then, the dewetting process takes place at 600oC for Au and 500oC for Ag. The particle distribution is quite non-uniform, making the shifting effect unclear and different from the previous result. However, the absorption effect of the BNNPs can be observed in this work, where it shows significantly broader peak spectra compared to both single Au and Ag NPs. This makes the BNNPs is the best candidate for selective detection sensors.
TLM analysis of metal contacts for 2D MoS2 nanoflakes deposited by chemical vapour deposition-free technique
In the past decade, two-dimensional (2D) nanomaterials are gaining significant attention due to their novel properties in electrical, optical, mechanical which are different from their bulk forms. Therefore, it becomes one of the most promising materials for sensing applications. However, to connect the 3D world with 2D materials require excellent communication links which is a contact that renders remarkable electrical properties and specifically 2D nanomaterials-based sensor has been suffering from high resistance and low sensitivity due to the loss caused by poor contact between the 2D nanomaterials and metal interface. This work explores the electrical properties of metal/2D contacts by the rectangular transmission line method (TLM). The critical resistance parameters such as sheet and specific contact resistance were determined by characterizing the current-voltage (IV) relation. The behavior of different metals (silver and gold) contacts to 2D MoS2 nanoflakes deposited on Si substrate by low-cost spray coating technique are observed. These metals are chosen based on the work function relative to the electron’s affinity, χ of MoS2. UV-Vis’s analysis is carried out to estimate the final concentration of MoS2 solution.
Green synthesis of silver nanoparticles using coffee extract for catalysis
The green synthesis method for producing metal nanoparticles has become more popular because it is more environmentally friendly and low cost. This study used a green approach to synthesize silver nanoparticles (AgNPs) using coffee Arabica bean's extract to reduce and stabilizing agents. The coffee extract was analyzed using GC-MS to identify the bioactive compounds in the extract, and Folin-Ciocalteu colorimetric test was done to find the total phenols in the extract. Later, the extract was used in the synthesis of AgNPs. Effects of synthesis parameters such as temperature, reaction time, pH, and amount of coffee extract on the formation of AgNPs were investigated. The formation of AgNPs was mainly observed using UV-Vis absorption spectroscopy. It was found that pH influenced the size of particles produced in which higher pH produce smaller particles than lower pH while other synthesis parameters mainly affected the yield of the AgNPs. The catalytic application of as-synthesized AgNPs was then evaluated in reducing methylene blue (MB) dye in a solution using NaBH4 as a reducing agent. The results show that the green-synthesized AgNPs were capable of catalyzing the reduction of MB dye in the solution.
Nonlinear optical properties of ZnO variants
Investigation on nonlinear optical properties of ZnO with Au-Ag NPs was done in this report using a femtosecond laser with a wavelength of 720 nm using Z-scan measurement. ZnO sample was prepared by a two-step process: seeding process via ultrasonic spray pyrolysis and growth process via hydrothermal methods, while ZnO with Au-Ag NPs was done by chemical reduction. ZnO shown saturable absorbance properties with nonlinear absorption coefficient, β = 1.63×10−6 cm/W, while ZnO deposited with Au-Ag NPs, shows reverse saturable absorption properties, for which ZnO Au NPs have the highest value of 5.60×10−6 cm/W, nonlinear refractive index response for pristine ZnO gave self-focusing effect with the value of a nonlinear refractive index, γ = 2.29×10−12 cm2/W. In contrast, the rest of ZnO with Au-Ag NPs gave the self-defocusing effect, with the Au NPs having the lowest response with γ = −5.79×10−12 cm2/W. This gives ZnO Au NPs have the highest third-order nonlinear susceptibility, χ(3) = 14.62×10−10 esu, which is an enhancement from pristine ZnO.
Acid hydrolysis process of mengkuang cellulose
Cellulose nanocrystals (CNC) are involved in many applications due to their unique properties. Thus, the understanding hydrolysis process help to control the preparation conditions and the chemical reactions during the different uses. Cellulose from mengkuang leaves (Pandanus tectorius) was used in this research to prepare CNC. Sulfuric acid (H2SO4 60 wt.%) hydrolysis was carried out over different times to produce the nanocrystals. The effects of hydrolysis time on the morphology, chemical structure, and crystallinity index of CNC were examined using transmission electron microscopy (TEM), Fourier transforms infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The degradation process is dependent on the time of hydrolysis and the crystalline domains of cellulose fibers. The process starts by expanding the cellulose chains. FTIR results showed that no change in the chemical structure of the nanocrystals during the hydrolysis reaction. The results demonstrated that the optimum hydrolysis time to produce cellulose nanocrystals from mengkuang cellulose, with a crystallinity index of about 74% and aspect ratio of 15, was 45 min at 45 °C using 60 wt% H2SO4.
Microwave-Assisted Synthesized Gadolinium Doped Barium Strontium Titanate Nanostructures: Structural and Optical Properties for DSSC Applications
Gadolinium (Gd) doped barium strontium titanate (BST) was prepared using the microwave-assisted solid-state reaction method for dye sensitized solar cell (DSSC) applications. The optical properties and the structural analysis of the prepared samples reveal the optical band gap and the morphology. The XRD pattern of the annealed samples confirms the polycrystalline nature with the cubic crystal structure. When the dopant is added, the bandgap increases slightly from 3.11 to 3.27 eV. The J-V characteristics of DSSCs prepared with pure and doped BST were investigated. The efficiency of the DSSCs remained constant and there is a slight increase in the Jsc for highly doped samples under 1-sun illumination. Gadolinium doped barium strontium titanate shows variation in the J-V characteristics and could be a potential candidate for the solar photovoltaic applications.
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