A numerical simulation model for laminar flow of nanofluids in a pipe with constant heat flux on the wall was built to study the effect of the Reynolds number on convective heat transfer and pressure loss. The investigation was performed for hybrid nanofluids consisting of CuO-Cu nanoparticles and compared with CuO and Cu in which the nanoparticles have a spherical shape with size 50, 50, 50nm respectively. The nanofluids were prepared, following which the thermal conductivity and dynamic viscosity were measured for a range of temperatures (10 -60°C). The numerical results obtained were compared with the existing well-established correlation. The prediction of the Nusselt number for nanofluids agrees well with the Shah correlation. The comparison of heat transfer coefficients for CuO, Cu and CuO-Cu presented an increase in thermal conductivity of the nanofluid as the convective heat transfer coefficient increased. It was found that the pressure loss increases with an increase in the Reynolds number, nanoparticle density and particle volume fraction. However, the flow demonstrates enhancement in heat transfer which becomes greater with an increase in the Reynolds number for the nanofluid flow.
In this study we used a laser ablation technique for preparation of silver nanoparticles. The fabrication process was carried out by ablation of a silver plate immersed in palm oil. A pulsed Nd:YAG laser at a wavelength of 1064 nm was used for ablation of the plate at different times. The palm coconut oil allowed formation of nanoparticles with very small and uniform particle size, which are dispersed very homogeneously within the solution. The obtained particle sizes for 15 and 30 minute ablation times were 2.5 and 2 nm, respectively. Stability study shows that all of the samples remained stable for a reasonable period of time.
Matched MeSH terms: Metal Nanoparticles/chemistry*
The release of chlorophenoxyherbicides agrochemicals, namely 2-chloro- (2CPA), 4-chloro and 2,4,5-trichloro (TCPA) phenoxyacetates from their nanohybrids into various aqueous solutions; carbonate, sulfate and chloride was found to be controlled by pseudo-second order rate expression. The percentage saturated released was found to be anionic-dependent, in the order of carbonate>sulfate>chloride for the release media and 2CPA>4CPA>TCPA for the anionic guests. This study demonstrates that the release of the phenoxyherbicides agrochemicals from the nanohybrid compounds can be tuned by choosing the right combination of exchangeable anions both the incoming and the outgoing anions.
Chitosan-ethylene glycol diglycidyl ether/TiO2 nanoparticles (CS-EGDE/TNP) composite was synthesized to be biosorbent for the removal of reactive orange 16 (RO16) dye from aqueous solution. The CS-EGDE/TNP composite was characterized via BET, XRD, FTIR, and SEM-EDX techniques. Response surface methodology (RSM) with Box-Behnken design (BBD) was applied to optimize the adsorption key parameters such as adsorbent dose (A: 0.02-0.08 g/L), RO16 dye concentration (B: 20-80 mg/L), solution pH (C: 4-10), temperature (D: 30-50 °C), and contact time (E: 30-90 min). The adsorption isotherm followed Freundlich model and pseudo-second order (PSO) kinetic model. The adsorption capacity of CS-EGDE/TNP for RO16 dye was 1407.4 mg/g at 40 °C. The adsorption mechanism of RO16 dye on the surface of CS-EGDE/TNP can be attributed to various interactions such as electrostatic attraction, n-π interaction, Yoshida H-bonding, and H-bonding. Results supported the potential use of CS-EGDE/TNP as effective adsorbent for the treatment of acid reactive dye.
Many plant-based bioactive compounds have been serving as the origin of drugs since long ago and many of them have been proven to have medicinal value against various chronic diseases, including, cancer, arthritis, hepatic diseases, type-2 diabetes and cardiovascular diseases. However, their clinical applications have been limited due to their poor water solubility, stability, low bioavailability and extensive transformation due to the first-pass metabolism. The applications of nanocarriers have been proven to be able to improve the delivery of bioactive phytoconstituents, resulting in the enhancement of various pharmacokinetic properties and thereby increasing the therapeutic value of phytoconstituents. These biocompatible nanocarriers also exert low toxicity to healthy cells. This review focuses on the uses and applications of different types of nanocarriers to enhance the delivery of phytoconstituents for the treatment of various chronic diseases, along with comparisons related to bioavailability and therapeutic efficacy of nano phytoconstituents with native phytoconstituents.
With the unique properties such as high surface area to volume ratio, stability, inertness, ease of functionalization, as well as novel optical, electrical, and magnetic behaviors, nanomaterials have a wide range of applications in various fields with the common types including nanotubes, dendrimers, quantum dots, and fullerenes. With the aim of providing useful insights to help future development of efficient and commercially viable technology for large-scale production, this review focused on the science and applications of inorganic and organic nanomaterials, emphasizing on their synthesis, processing, characterization, and applications on different fields. The applications of nanomaterials on imaging, cell and gene delivery, biosensor, cancer treatment, therapy, and others were discussed in depth. Last but not least, the future prospects and challenges in nanoscience and nanotechnology were also explored.
In present work, we demonstrate a single step environmentally benign approach to synthesize Au/Ag bimetallic nanoparticles (BMNPs) using aqueous extract of Clove buds for the first time. Clove bud's (CB) extract has proficiency to act as a reducing and stabilizing agent for the formation of Au/Ag BMNPs. In presence of extract, AuIII and AgI are reduced competitively within same solution and produce Au/Ag alloy NPs. The kinetics besides the formation of NPs was studied using UV-visible spectroscopy and efficiency of the extract was monitored by varying contact time, temperature, pH and extract concentration. The electron microscopic studies revealed the presence of NPs with peculiar morphology at alkaline pH. Further, the existence of Au and Ag atoms was investigated using energy dispersive X-ray (EDX), X-ray diffraction (XRD) and cyclic voltammetry (CV) techniques. Fourier transform infrared spectroscopy (FTIR) showed that Eugenol in the extract is mainly responsible for the production of NPs which are also surrounded by various phytochemicals. Zeta potential of all the NPs is found to be negative which prevents their agglomeration due to inter-repulsion and the biosynthesized Au/Ag BMNPs revealed greater catalytic efficiency for the degradation of methyl orange (MO), methylene blue (MB) and reduction of p-nitrophenol (p-NP). Significant enhancement induced by BMNPs compared to individual monometallic nanoparticles (MMNPs) was assigned to the synergistic effect of MMNPs and coating of phytochemicals present in the CB extract.
This manuscript describes the reuse of biowaste for the biosynthesis of silver nanoparticles (AgNPs) and their applications. In particular, we hypothesized that the phytochemicals in the onion peels could act as reductant for silver nanoparticles syntheses. AgNO3 solution (1 mmol) was added dropwise to an aqueous solution of onion peel extract in 3:7 ratio. The reaction mixture was subjected to heating at 90 °C for about 30 min. During the synthesis of the AgNPs, the change of the colour of solution was observed. The AgNPs solution was centrifuged to obtain the two layers, which consists of clear solution and solid layers at 12000 rpm for 30 min. The precipitate was filtered and was re-dispersed in deionised water (25 mL). The solution was centrifuged again to obtain the purified AgNPs. Subsequently, this solution was freeze dried for 48 h to afford the powdered AgNPs. In this work, the structure of the AgNPs were synthesized in spherical shape, with an average size of 12.5 nm observed in the Transmission electron microscopy (TEM) analysis. For catalytic application, the synthesized AgNPs could be applied as green catalyst to promote Knoevenagel and Hantzsch reactions. In most cases, the desired products were obtained in satisfactory yields. In addition, the AgNPs were found to be recyclable for the subsequent reactions. After five successive runs, the average isolated yields for both transformations were recorded to be 91% (Knoevenagel condensation) and 94% (Hantzsch reaction), which indicated that the existing AgNPs could apply as green catalyst in the field of organic synthesis. Furthermore, the AgNPs also showed satisfactory result in antioxidant activity. The current results indicate that the AgNPs can act as alternative antioxidant agent and green catalyst in mediating organic transformations.
Olive fiber is a sustainable material as well as alternative biomass for extraction of nanocrystalline cellulose (NCC), which has been widely applied in various industries. In the present study, ONC-I, ONC-II, and ONC-III were extracted from olive stem fiber at different hydrolysis reaction times of 30 min, 45 min, and 60 min, respectively. The nanoparticle size was found gradually reducing from ONC-I (11.35 nm width, 168.28 nm length) to ONC-III (6.92 nm width, 124.16 nm length) due to the disintegration of cellulose fibrils. ONC-II and ONC-III possessed highly pure cellulose compartments and enhanced crystals structure. This study also showed that rigidity increased from ONC-I to ONC-II. ONC-III showed the highest crystallinity of 83.1 %, endowing it as a potentially reliable load-bearing agent. Moreover, ONC-III exhibited highest stable heat resistance among the chemically-isolated nanocellulose. We concluded that olive NCC could be promising materials for a variety of industrial applications in various fields.
Despite enormous advancements in the field of oncology, the innocuous and effectual treatment of various types of malignancies remained a colossal challenge. The conventional modalities such as chemotherapy, radiotherapy, and surgery have been remained the most viable options for cancer treatment, but lacking of target-specificity, optimum safety and efficacy, and pharmacokinetic disparities are their impliable shortcomings. Though, in recent decades, numerous encroachments in the field of onco-targeted drug delivery have been adapted but several limitations (i.e., short plasma half-life, early clearance by reticuloendothelial system, immunogenicity, inadequate internalization and localization into the onco-tissues, chemoresistance, and deficient therapeutic efficacy) associated with these onco-targeted delivery systems limits their clinical viability. To abolish the aforementioned inadequacies, a promising approach has been emerged in which stealthing of synthetic nanocarriers has been attained by cloaking them into the natural cell membranes. These biomimetic nanomedicines not only retain characteristics features of the synthetic nanocarriers but also inherit the cell-membrane intrinsic functionalities. In this review, we have summarized preparation methods, mechanism of cloaking, and pharmaceutical and therapeutic superiority of cell-membrane camouflaged nanomedicines in improving the bio-imaging and immunotherapy against various types of malignancies. These pliable adaptations have revolutionized the current drug delivery strategies by optimizing the plasma circulation time, improving the permeation into the cancerous microenvironment, escaping the immune evasion and rapid clearance from the systemic circulation, minimizing the immunogenicity, and enabling the cell-cell communication via cell membrane markers of biomimetic nanomedicines. Moreover, the preeminence of cell-membrane cloaked nanomedicines in improving the bio-imaging and theranostic applications, alone or in combination with phototherapy or radiotherapy, have also been pondered.
Aim: This study was aimed at evaluating the anticancer potential of curcumin-loaded poly(lactic-co-glycolic acid) (PLGA) based nanoparticles (NPs) in MDA-MB231 human breast cancer cells. Methods: Curcumin-loaded PLGA NPs were developed using a modified solvent evaporation technique. Physical characterization was performed on the formulated NPs. Furthermore, in vitro experiments were conducted to study the biological activity of the curcumin-loaded NPs. Results: Curcumin-loaded PLGA NPs demonstrated high encapsulation efficiency and sustained payload release. Moreover, the NPs exhibited a significant reduction in cell viability, cell migration and cell invasion in the MDA-MB231 cells. Conclusion: The study revealed that the formulated curcumin-loaded PLGA NPs possessed significant anti-metastatic properties. The findings showcased the possible potential of curcumin-loaded NPs in the management of debilitating conditions such as cancer. In addition, this study could form the basis for further research and advancements in this area.
Inorganic nanoparticles are commonly employed as vectors for delivering drugs into cancer cells while decreasing undesired cytotoxicity in healthy tissues. Carbonate apatite is an attractive nonviral vector that releases drugs at acidic environment inside the cells following endocytosis. However, maintaining the smaller particle size is crucial for enhancing cellular uptake of drugs as well as prolonging their systemic circulation time. We aimed to modify carbonate apatite with citrate for reducing the growth kinetics of carbonate apatite particles and enhancing the cellular uptake of cyclophosphamide via endocytosis. Several concentrations of sodium citrate were used to fabricate citrate-modified carbonate apatite (CMCA) particle complexes in absence or presence of cyclophosphamide. The binding affinity of the drug towards the particles and its cellular uptake were measured by high-performance liquid chromatography (HPLC). The nanoparticles' average size and zeta potential were determined by Malvern Zetasizer. Fourier-transform infrared spectroscopy (FTIR) was performed to justify association of citrate with carbonate apatite. MTT assay was performed to evaluate the cell viability. CMCA exhibited 6% more binding efficiency for cyclophosphamide and promoted fast cellular uptake of cyclophosphamide with enhanced cytotoxicity in MCF-7 cells, compared to unmodified carbonate apatite. Therefore, CMCA nanoparticles have a high potential for intracellular delivery of anti-cancer drugs and demand for further investigated in animal models of cancer.
The utilization of carbon dioxide for the production of valuable chemicals via catalysts is one of the efficient ways to mitigate the greenhouse gases in the atmosphere. It is known that the carbon dioxide conversion and product yields are still low even if the reaction is operated at high pressure and temperature. The carbon dioxide utilization and conversion provides many challenges in exploring new concepts and opportunities for development of unique catalysts for the purpose of activating the carbon dioxide molecules. In this paper, the role of carbon-based nanocatalysts in the hydrogenation of carbon dioxide and direct synthesis of dimethyl carbonate from carbon dioxide and methanol are reviewed. The current catalytic results obtained with different carbon-based nanocatalysts systems are presented and how these materials contribute to the carbon dioxide conversion is explained. In addition, different strategies and preparation methods of nanometallic catalysts on various carbon supports are described to optimize the dispersion of metal nanoparticles and catalytic activity.
Matched MeSH terms: Metal Nanoparticles/chemistry*
Photothermal therapy (PTT) is a minimally invasive procedure for treating cancer. The two significant prerequisites of PTT are the photothermal therapeutic agent (PTA) and near-infrared radiation (NIR). The PTA absorbs NIR, causing hyperthermia in the malignant cells. This increased temperature at the tumor microenvironment finally results in tumor cell damage. Nanoparticles play a crucial role in PTT, aiding in the passive and active targeting of the PTA to the tumor microenvironment. Through enhanced permeation and retention effect and surface-engineering, specific targeting could be achieved. This novel delivery tool provides the advantages of changing the shape, size, and surface attributes of the carriers containing PTAs, which might facilitate tumor regression significantly. Further, inclusion of surface engineering of nanoparticles is facilitated through ligating ligands specific to overexpressed receptors on the cancer cell surface. Thus, transforming nanoparticles grants the ability to combine different treatment strategies with PTT to enhance cancer treatment. This review emphasizes properties of PTAs, conjugated biomolecules of PTAs, and the combinatorial techniques for a better therapeutic effect of PTT using the nanoparticle platform.
Maintenance of oral health is a major challenge in dentistry. Different materials have been used to treat various dental diseases, although treatment success is limited by features of the biomaterials used. To overcome these limitations, materials incorporated with nanoparticles (NPs) can be used in dental applications including endodontics, periodontics, tissue engineering, oral surgery, and imaging. The unique properties of NPs, including their surface:volume ratio, antibacterial action, physical, mechanical, and biological characteristics, and unique particle size have rendered them effective vehicles for dental applications. In this review, we provide insights into the various applications of NPs in dentistry, including their benefits, limitations, properties, actions and future potential.
Gums; composed of polysaccharides, carbohydrates, proteins, and minerals, are high molecular weight hydrophilic compounds with several biological applications. This study describes the nutritional and toxic elements content, chemical composition, synthesis of silver nanoparticles (G-AgNPs), and pharmacological and catalytic properties of Prunus armeniaca (apricot), Prunus domestica (plums), Prunus persica (peaches), Acacia modesta (phulai), Acacia arabica (kikar), and Salmalia malabarica (silk cotton tree) gums. The elemental contents were analyzed by inductively coupled plasma-optical emission spectroscopy (ICP-OES) and ICP-mass spectrometry (ICP-MS). NMR spectroscopy was used for the identification of class of compounds in the mixture, their functional groups were determined through FTIR techniques, and plasmon resonance and size of G-AgNPs through UV-Vis spectroscopic technique and transmission electron microscopy (TEM). From the results, nutritional elements were present at appreciable concentrations, whereas toxic elements showed content below the maximum permissible ranges. Using the elemental data, linear discriminant and principal component analyses classified the gums to 99.9% variability index. Furthermore, G-AgNPs exhibited significant antioxidant, antibacterial, and redox catalytic potential. Hence, the subject G-AgNPs could have promising nutritional, therapeutic and environmental remediation applications.
Matched MeSH terms: Metal Nanoparticles/chemistry*
Biofilm represents one of the crucial factors for the emergence of multi-drug resistance bacterial infections. The high mortality, morbidity and medical device-related infections are associated with biofilm formation, which requires primarily seek alternative treatment strategies. Recently, nanotechnology has emerged as a promising method for eradicating bacterial biofilm-related infection. The efficacy of nanoparticles (NPs) against bacterial infections interest great attention, and the researches on the subject are rapidly increasing. However, the majority of studies continue to focus on the antimicrobial effects of NPs in vitro, while only a few achieved in vivo and very few registered as clinical trials. The present review aimed to organize the scattered available information regarding NPs approach to eradicate bacterial biofilm-related infections. The current review highlighted the advantages and disadvantages associated with this approach, in addition to the challenges that prevent reaching the clinical applications. It was appeared that the production of NPs either as antimicrobials or as drug carriers requires further investigations to overcome the obstacles associated with their kinetic and biocompatibility.
A simple, inexpensive but effective approach for visual chiral recognition of ketoprofen enantiomers was developed using L-cysteine capped silver nanoparticles (L-Cys-AgNPs) as a colorimetric sensor. Upon the addition of R-ketoprofen to L-Cys-AgNPs, rapid aggregation occurred, and the solution changed color from yellow to green. However, the presence of S-ketoprofen did not induce any color change. The results were characterized using UV-Vis, FESEM, FT-IR, SERS, and zeta potential measurements. The chiral assay described in this work is easily distinguished with the naked eyes or using a UV-Vis spectrometer. The sensor revealed a good linear response to ketoprofen enantiomers in the concentration range of 8.33-33.3 μM with a detection limit of 4.52 μM and relative standard deviation of 3.73%. The proposed method was utilized for the determination of ketoprofen racemic mixtures in water samples and commercial tablets. The method excels by its simplicity, low cost, and good availability of materials.
The present work demonstrates the coupling of titanium dioxide, TiO2 nanoparticles (TNP) with N-doped, Bi-doped, and N-Bi co-doped rice husk-derived carbon dots (CDs) via a facile dispersion method, forming respective photocatalyst composites of CDs/TNP, N-CDs/TNP, Bi-CDs/TNP and N-Bi-CDs/TNP. Characterization analyzes verified the successful incorporation of respective CDs samples into TNP, forming photocatalyst composite with narrowed band gap and quenched photoluminescence intensity. Photocatalytic activity of TNP and the respective composites was investigated for photodegradation of diclofenac (DCF) under both simulated sunlight and natural sunlight irradiation. The as-prepared N-Bi-CDs/TNP composite showed the best photocatalytic performance among all composites, able to completely degrade 5 ppm of DCF within 60 min and 180 min under both types of visible light irradiation, respectively. The N-Bi-CDs/TNP composite also showed a TOC removal efficiency up to 87.63%. N-Bi-CDs, worked as photosensitizer and electron reservoir, contributed to the outstanding photocatalytic activity of N-Bi-CDs/TNP, whereby the recombination was prolonged and light absorption was shifted towards the visible light region. Furthermore, the composite of N-Bi-CDs/TNP also demonstrated good stability and reusability over repeated degradation cycles. The photodegradation of DCF resulted into several intermediates, which were identified from LC-MS analysis. The present work could provide an insight on the application of heteroatoms doped and co-doped carbon dots in semiconductor oxide as high performance photocatalysts.