Current Nanoscience - Volume 20, Issue 5, 2024

Graphene gas sensors have gained much scientific interest due to their high sensitivity, selectivity, and fast detection of various gases. This article summarizes the research progress of graphene gas sensors for detecting ammonia gas at room temperature. Firstly, the performance and development trends of the graphene/semiconductor Schottky diode sensor are discussed. Secondly, manufacturing methods and the latest developments in graphene field-effect transistor sensors are reviewed. Finally, the basic challenges and latest efforts of functional ammonia gas sensors are studied. The discussion delves into each sensor type's detection principles and performance indicators, including selectivity, stability, measurement range, response time, recovery time, and relative humidity. A comparative analysis is conducted to highlight the progress achieved in research, elucidating the advantages, disadvantages, and potential solutions associated with various sensors. As a result, the paper concludes by exploring the future development prospects of graphene-based ammonia sensors.

The world is fighting a pandemic so grave that perhaps it has never been witnessed before; COVID-19 is caused by the severe acute respiratory syndrome coronavirus 2 (SARSCoV- 2). As of August 31st, 2022, the WHO declared the total number of confirmed cases was 599,825,400, with 6,469,458 confirmed deaths from 223 countries under the scourge of this deadly virus. The SARS-CoV-2 is a β-coronavirus, which is an enveloped non-segmented positive- sense RNA virus. It is a close relative of the SARS and MERS viruses and has probably entered humans through bats. Human-to-human transmission is very rapid. People in contact with the patient or even the carriers became infected, leading to a widespread chain of contamination. We are presenting a mini-review on the role of biosensors in detecting SARS-CoV-2. Biosensors have been used for a very long time for viral detection and can be utilized for the prompt detection of the novel coronavirus. This article aims to provide a mini-review on the application of biosensors for the detection of the novel coronavirus with a focus on costeffective paper-based sensors, nanobiosensors, Field effect transistors (FETs), and lab-on-chip integrated platforms. Background: Biosensors have played a crucial role in viral detection for a long time. Objectives: To present a comprehensive review of the biosensor application in SARS-Cov-2. Methods: We have presented state-of-the-art work in the biosensors field for SARS-Cov-2 detection. Results: The biosensors presented here provide an innovative approach to detecting SARS-Cov- 2 infections early. Conclusion: Biosensors have tremendous potential in accurately detecting viral infections in pandemics requiring rapid screening.

Virus-like particles (VLPs) are nanoscale, self-assembling cage structures made out of proteins with practical uses in biomedicine. They might be used to create better vaccinations, imaging equipment, gene and drug therapy delivery systems, and in vitro diagnostic equipment. VLPs are nanostructures that might be used in medicine, immunization, and diagnostics, among other areas. Many VLPs-based vaccines are now in use for the treatment of infectious diseases, and many more are on their way to clinical testing thanks to recent advancements in biomedical engineering. Although VLPs exhibit promising qualities in terms of efficacy, safety, and diversity, they may become more widely used in the future. Vaccines based on virus-like particles (VLPs) might serve as an effective addition to current immunization strategies for the prevention and treatment of emerging infectious diseases. The growing field of healthcare prevention has become increasingly interested in VLPs, leading to the discovery of various VLP-based candidate vaccines for vaccination towards a wide range of infectious pathogens, one of the most recent that has been developed is the vaccine against SARS-CoV-2, the effectiveness of that is now being tested. VLPs can elicit both antibody and cell-mediated immune responses, unlike standard inactivated viral vaccines. However, several problems persist with this surface display method and will need fixing in the future. VLPs-based medicinal delivery, nanoreactors for treatment, and imaging systems are being developed with promising results. The latest developments in the generation and fabrication of VLPs involve explorations of several expression systems for their creation and their application as vaccines for the avoidance of infectious diseases and malignancies. This manuscript offers the most advanced perspective on biomedical applications based on VLPs, as well as details innovative methods for manufacturing, functionalization, and delivery of VLPs.

Essential oils (EOs), which are volatile aromatic substances extracted from plants, exhibit antibacterial, antitumor, antiviral, antioxidant, anti-inflammatory, and other effects. Eos are widely used in different fields because of their various biological activities. EOs are volatile and insoluble in water, so their effective utilization rate is greatly reduced. In this regard, researchers propose to use nanotechnology to construct an EOs nanosystem to solve the application problems and improve the utilization rate of EOs. This review summarizes the latest research progress and application status of EOs nanocapsules, EOs nanoemulsion, EOs nanofiber membrane, EOs nanoparticles and EOs nanoliposome, including the methodologies, characteristics and applications.Analyzes the advantages and disadvantages of existing EOs nanotechnology and provides an outlook for future development.

Solid lipid nanoparticles (SLN) have several potential uses in research for medicine such as drug discovery and drug delivery, an area at the forefront of evolving area of nanobiotechnology. In general, SLNs were created to address the drawbacks of conventional colloidal carriers, including emulsions, liposomes, and polymeric nanoparticles since they provide various advantages such as favourable release profiles and tailored drug delivery with outstanding physical-chemical stability. Solid lipid nanoparticles are spherical solid lipid particles that are distributed in water or an aqueous surfactant solution and are in the nanometer size range. Therefore, SLN is used to deliver hydrophilic and lipophilic drugs. The review article focuses on various aspects of SLN including the structure, the influence of excipients, the drug incorporation model, the principle of release, the method of preparation, characterization, the route of administration and biodistribution, and the application of SLN.

Carbon dots belong to the class of nanomaterials invented accidentally and are attracting a lot of attention these days. Carbon dots are non-toxic, photostable, and easy-to-synthesize nano formulations having good water-soluble properties when treated chemically by manipulating surface active groups, followed by the addition of solubilizing agents and size reduction. These are widely used in bioimaging, electrochemical sensing, targeted drug delivery, and other biomedical activities. In recent years, significant attempts have been emphasized by analysts to the detection of vitamins embedded carbon dots using biosensors. The biosensing of vitamins has become easy due to the luminescence property of carbon dots, which makes them easy to detect. Therefore, in this review, we have reported synthetic strategies and recent biosensorbased detection techniques used in the analysis of vitamin-loaded carbon dots. Even from the carbon dot’s analytical perspective, there is still a lot of research needed in the area of biosensing, bioimaging, and healthcare applications. Unique features, along with the controllable synthesis methods, will lead to a bright future in the detection and characterization of drugs using carbon dots.

Background: To enhance the super capacitive properties of nanocomposites, the effective method is to combine carbon nanospheres with mesoporous structures with Gd³⁺:α-Sb2O4 inorganic nanocomposites (NC) to form hybrid electrodes. An as-prepared hybrid electrode material possesses increased energy density, high rate of reversibility and cyclic stability when incorporated in electrochemical cyclic voltammetric studies. Methods: In the present investigation, various wt % of C-nanospheres (Cx) (5 %, 10% and 20%) were decorated over Gd³⁺: α-Sb2O4 nanocomposites and were synthesized by coprecipitation method. XRD, SEM, EDX, UV-visible, and XPS are only a few of the analytical techniques used to describe the as-prepared hybrid nanocomposites. Electrochemical cyclic voltammetry was carried out in a 6 M KOH solution, three-electrode system. Results: The crystal structure and morphology of Cx: Gd³⁺@ α-Sb2O4 NC showed a mixed hexagonal phase and agglomerated tiny irregularly shaped morphology that appeared as the Cx concentration increased. Redshift in optical absorption peak appeared (near UV-edge), and the optical band gap (Eg) value increased from 3.53 eV to 3.65 eV. The electrochemical supercapacitor showed the highest specific capacitance of 989 F/g at the current density of 1 A/g for C20%:Gd³⁺@α-Sb2O4 NC compared with Cx:Gd³⁺@α-Sb2O4 (x = 5% and 10%) and undoped Gd³⁺:α-Sb2O4 NC. The change in phase angle and Rs value of 1.98 was attributed to the ideal supercapacitor properties. The cyclic stability after 5000 cycles with 79.71% capacitive retention was exhibited by C20%:Gd³⁺@α-Sb2O4 NC. Conclusion: The present research introduces ease of synthesis of hybrid electrode materials possessing high active surface area, increased energy density, high cyclic stability, and reversibility in an aqueous solution.