Current Nanoscience - Volume 18, Issue 5, 2022

The atomic force microscope (AFM) is widely used in many fields such as biology, materials, and physics due to its advantages of simple sample preparation, high-resolution topography measurement and wide range of applications. However, the low scanning speed of traditional AFM limits its dynamics process monitoring and other further application. Therefore, the improvement of AFM scanning speed has become more and more important. In this review, the working principle of AFM is first proposed. Then, we introduce the improvements of cantilever, drive mechanism, and control method of the high-speed atomic force microscope (HS-AFM). Finally, we provide the next developments of HS-AFM.

Magnetic nanoparticles (MNPs) have unique properties that have made them widely used in medicine and biology. They are easy to work with due to their responsiveness to external magnetic force. Functionalization of nanoparticles(NPs) effectively improves performance, increases stability in the body and acidic environment, and prevents the agglomeration of the particles. One of the important applications of these NPs is in the separation of materials as solid-phase extracting agents. On the other hand, functionalizing these NPs can increase the efficiency, stability, specificity, and sensitivity of the structure to separate the target. In this paper, various material separation studies were collected and classified into several main groups based on material types. Study groups included functional MNPs for separating pathogen, organic and inorganic substances of environmental resources, removal of heavy metal ions, separation of biomolecules, isolation of cells, especially tumor cells, and harvesting the microalgae. The results showed that this method has advantages such as high sensitivity and specificity, is easy to use without needing an operator, low costs, and is a time-saving technique for not requiring sample preparation and concentration.

Nanowires (NWs) have received extensive attention as the candidate materials for transparent conductive films (TCFs) in recent years. To date, the aligned nanowire (NW)-based TCFs with the same arrangement direction have shown superior characteristics to their random counterparts in applications. To fully develop the potential of NW TCFs in devices and provide inspiration for the development of subsequent NW alignment processes, this review summarizes state-of-the-art alignment techniques and emphasizes their mechanisms in detail from multiple perspectives. According to the mechanism of NW alignment, this review divides these techniques into seven categories, i.e., the assisted assembly of fluid flow, meniscus, pressure, template, electromagnetic field, contact and strain, and analyzes the characteristics of these techniques. Moreover, by briefly enumerating the applications of aligned NW films in solar cells, organic light-emitting diodes, and touch screens, the superiority of aligned NW films over random NW films is also addressed. Contact-assisted assembly exhibits the best arrangement effect, reaching a 98.6% alignment degree within ±1°. Under the same conditions, shorter NWs show better alignment in several cases. The combination of various assembly techniques is also an effective means to improve the alignment effect. There is still room for improvement in the precise control of NW position, density, and orientation in a simple, efficient and compatible process. Therefore, follow-up research work is needed to conquer these problems. Moreover, a process that can realize NWs’ alignment and film patterning simultaneously is also a desirable scheme for fabricating personalized devices.

Delivery of anti-cancer agents is challenging due to some inherent problems associated with them like instability, low solubility, non-specificity, variable pharmacokinetics, narrow therapeutic window, multi-drug resistance development, and other physiological barrier related to tumor cells. In recent years, Nanostructured lipid carrier (NLC) has gained considerable importance in improving anti-cancer agents' therapeutic efficacy. The present review furnishes a comprehensive account of various barriers encountered in delivering the anti-cancer agent, the suitability of NLC to deliver anti-cancer agent, the techniques employed for the fabrication of NLC, its structure, along with its characterization. The main emphasis has given a break worth to overcome barriers in delivering chemotherapeutic through NLC so far; a number of qualitative literature have been included in this review. Further, the study describes the stability issue associated with the long-term storage of NLC. The NLCs systems offer a great potential to target various anti-cancer agents suffering from low solubility, non-specificity, and severe adverse effects. The NLC system's development can overcome barriers encountered in delivering anti-cancer agents and improve its efficacy in various melanoma types.

In the field of plant biotechnology, tissue culture is having colossal applications, for example, the production of disease-free plants and their mass multiplication, germplasm preservation, genetic manipulation to get improved variety as well as the production of biologically active compounds. The integration of nanotechnology and application of Nanoparticles (NPs) has shown a positive response in the elimination of microbial contaminants and induction of callus, somatic embryogenesis, organogenesis, production of secondary metabolites, and genetic transformation. This paper aims to highlight some of the recent advancements that came possible through the implementation of nanotechnology in the field of plant tissue culture and also discusses both positives and negatives aspects associated with NPs in plant tissue culture. The prospects through the involvement of recent innovations of nanotechnology such as dendrimers, quantum dots, and carbon nanotubes are also proposed.

Background: Over 300 tonnes of gold are utilised in electronic devices every year all over the world. End-of-life of these electronic equipments offers a crucial recycling potential as a secondary gold supply. Electronic boards are among common and exploitable gold sources that are widely used in various industries. The aim of this paper is to use the gold element of electronic boards by adjusting its surface functionality and also its particle size to make this metal an adequate material to be used in various applications. Methods: To achieve this purpose, by using acidic solutions and via up to bottom chemical synthesis method among physical, chemical, and biological methods and in addition, by transferring gold particle size from micrometer to nanometer (to gain good nano-dimension properties), the surfacearea- to-volume ratio will experience an increase such that new structural properties emerge, change, or improve. Results: Analysis of the results using Fourier-Transform Infrared spectroscopy, X-Ray Diffraction, and Field Emission Scanning Electron Microscopy have confirmed high-quality production and proper extraction of gold particles on a nanometer scale from electronic plates and confirmed the crystalline structure of extracted gold in the particle size range of 70-110 nm. Conclusion: The main objective of this research is to derive and fabricate gold nanoparticles using oxidative chemical route using HCl and Aqua regia to produce gold nanoparticles on Nano dimension scale. Results have shown that gold nanoparticles are synthesized successfully via a chemical process. Moreover, acid concentration and reaction time have an enormous effect on the gold nanoparticle production procedure.

Background: Exosomes-a subset of extracellular vesicles (EVs)-are secreted by virtually all cells, including human neuroblastoma cancer (SH-SY5Y) cells, into bodily fluids. Oxidative stress is critically involved in exosome biogenesis and release. Silver nanoparticles (AgNPs) induce cytotoxicity, oxidative stress, and apoptosis in cancer and non-cancer cells. Methods: Here, we studied whether AgNPs-induced oxidative stress could enhance exosome biogenesis and release under low serum conditions in the presence of AgNPs. Although several studies have reported various mechanisms that contribute to EV biogenesis and release from cells, none exists on the involvement of external stimuli by controlling acetylcholinesterase (AChE) and neutralsphingomyelinase (n-SMase) activities, total protein concentration of exosomes, and exosome count. Results: Owing to cytotoxic and oxidative stresses, AgNPs-treated cells and exosome release were significantly facilitated, which strongly correlated with the AgNPs-induced oxidative stress. Moreover, the expression levels of some important exosome biomarkers were found to be significant under oxidative stress conditions. N-acetylcysteine prevented oxidative stress-induced exosome biogenesis and release. Furthermore, we identified the involvement of the ceramide pathway in exosome functions by inhibiting AChE and n-SMase activities, and exosome protein/counts. These data contribute to the understanding of how AgNPs and intracellular molecular pathways affect exosome biogenesis and release in SH-SY5Y cells. Conclusion: To the best of our knowledge, this is the first study showing that AgNPs stimulate exosome biogenesis and release by inducing oxidative stress and ceramide pathways.

Background: Due to their extremely small size, large surface area, and magnetism, magnetite nanoparticles (Fe3O4NPs) have distinct chemical and physical properties, enhancing their suitability for a variety of medical, biosensing, electronic, and environmental applications. Methods: Magnetite nanoparticles were easily obtained by green synthesis using leaf extracts of the South American endemic Cryptocaria alba (Peumo) tree. FeNPs were characterized by using UV-visible spectrophotometry, Transmission Electronic Microscopy (TEM), Dynamic Light Scattering (DLS), Laser Doppler Velocimetry (LDV), X-ray Diffraction (XRD), and Thermogravimetric Analysis (TGA). Results: Fe3O4NPs were successfully synthetized, and they showed crystalline nature, primary dry diameter means between 12 nm and 15 nm, spherical apparent shape, and good stability in aqueous suspension. Additionally, preliminary studies indicated that low concentrations of magnetite nanoparticles (1000 times lower than the literature reported) reduced chemical oxygen demand (COD), apart from concentrations of total phosphates and nitrates from pisciculture wastewater samples incubated for 24 h. Conclusion: Green synthesis of Peumo iron nanoparticles is an easy, fast, and viable ecofriendly bioprocess under certain conditions of fabrication to obtain nanometric and stable iron particles with promising removal properties of nitrates, phosphates, and COD from wastewaters.