Nano LIFE

Cold atmospheric plasma (CAP), known for its ability to generate Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS), has emerged as a promising tool in many biomedical applications, including cancer therapeutics and virus inactivation. In cancer therapy, ROS and RNS induced by plasma have been shown to selectively target cancer cells, triggering apoptosis and inhibiting tumor growth while sparing healthy cells. This selective cytotoxicity makes plasma an attractive option for localized cancer treatment with minimal side effects. Additionally, the antimicrobial properties of ROS and RNS make plasma an effective agent for virus inactivation. By connecting the dots between cancer therapy and virus disinfection, this review paper sheds light on the potential of plasma-generated ROS and RNS as versatile tools in medical applications, offering a dual benefit of targeted cancer treatment and effective virus control. Specifically, this review explores the effects of CAP treatment on B16 melanoma cells, assessing changes in cell viability, proliferation, apoptosis and oxidative stress response. Dichloroacetate (DCA), a mitochondrial modulator, has shown promise in inducing apoptosis in melanoma cells. However, its clinical use is limited by side effects related to its neurotoxicity and suspected carcinogenicity. The potential of CAP in enhancing the therapeutic efficacy of DCA on B16-F10 melanoma apoptosis is also explored. CAP therapeutics for other types of cancers are also explored in this review. Alongside its implications in oncology, CAP has gathered substantial attention for its extraordinary potential in neutralizing viruses. CAP’s exceptional precision in targeting viral envelopes, genetic material and structural components disrupts their integrity and vital functions. This orchestrated mechanism offers a swift and efficacious route to render viruses inactive, encompassing both enveloped and nonenveloped viral types. In parallel pursuit, this review examines CAP-generated reactive species’ proficiency in deactivating SARS-CoV-2 across various surfaces. The inquiry entails subjecting surfaces to CAP treatment, succeeded by quantifying viral load and scrutinizing viral integrity. The outcomes gleaned from these investigations provide pivotal insights into CAP’s potential as a robust surface disinfection strategy, poised to combat the propagation of viral transmission.

A novel cupric oxide nanoparticles (CuO NPs) infused graphite electrode (CuO@GP) was synthesized for simultaneous detection of epicatechin (EC) and theophylline (TH) in black tea. The CuO NPs were synthesized via the sol–gel method and characterized using X-ray diffraction and a scanning electron microscope. The electrochemical sensor performance was studied using cyclic voltammetry and differential pulse voltammetry revealing the presence of TH and EC simultaneously in black tea. The electrode demonstrated a linear range of 50.0–100.0 $\mu$M for both analytes, with a room temperature limit of detection (4.0 $\mu$M for EC, 27.0 $\mu$M for TH). Under the optimal conditions, it showed repeatability (with a relative standard deviation (RSD): 1.61% EC, 0.96% TH), reproducibility (RSD: 1.07% EC, 1.14% TH) and stability (RSD: 2.16% EC, 2.15% TH). CuO@GP exhibited notable selectivity and promising results in tea samples, achieving recovery rates of 102–107% for EC and 101.7–106% for TH.

This study describes an easy and cheap inkjet printing method for producing a paper-based gas sensor consisting of a composite film made of graphene oxide and poly(3,4-ethylenedioxythiophene) and poly(styrenesulfonate) (PEDOT:PSS). A glossy paper substrate is an inkjet printed with ink made by dispersing graphene oxide in a PEDOT:PSS conducting polymer solution to test its ability to detect ammonia (${\text{NH}}_3)$ at ambient temperature. The presence of few-layer graphene oxide in the PEDOT:PSS copolymer and the existence of $\pi$–$\pi$ interactions between graphene oxide and PEDOT:PSS are confirmed by Fourier transform infrared spectroscopy, UV–Visible spectrophotometer, and X-ray diffraction. In a small concentration range of 1–100 ppm at ambient temperature, the ink-jet printed graphene oxide-PEDOT:PSS gas sensor displays strong responsiveness and good selectivity to NH₃. The study found that ${\mathrm{\text{NH}}}_4$ is a strong donor in the ammonia gas produced by a bubble system of ammonia water, with ${\mathrm{\text{NH}}}_4$ molecules being ideal candidates for molecular doping of graphene. The ${\mathrm{\text{H}}}_2\mathrm{\text{O}}$ molecule can facilitate quick desorption by converting ${\mathrm{\text{NH}}}_3$ to ${\mathrm{\text{NH}}}_4$. The interaction between graphene oxide and ${\mathrm{\text{NH}}}_3$ molecules is weak. The attained gas-sensing performance may be attributed to the increased specific surface area of graphene oxide and enhanced interactions between the sensing film and ${\mathrm{\text{NH}}}_3$ molecules via $\pi$ and lone pair electron network. The ${\mathrm{\text{NH}}}_3$-sensing mechanisms of the flexible printed gas sensor are based on the competitive interaction of ammonia on the sensor, adsorption and dissociate ionization on the sensor surface.

Carica papaya seeds were used in this research for the synthesis of AgNPs. The production of silver nanoparticles was characterized using UV–Vis spectroscopy, FTIR, XRD and SEM-EDX analysis. The antibacterial activity of the prepared AgNPs was evaluated by the Kirby–Bauer disc diffusion method with the antibacterial activity of different compounds against Bacillus aerogenes. UV–Vis spectral peaks are found at 8–18 nm. SEM and TEM analysis revealed several spherical structures between 10 nm and 50 nm. XRD analysis also confirmed its 50 nm size. Experimental data revealed that AgNPs inhibited bacterial growth. This study shows that papaya seed extract contributes to the bioreduction and stabilization of the synthesized silver nanoparticles.

Antimicrobial medicines serve as the bedrock of modern medical practices. Increasing multidrug resistance compromises surgical processes and increases healthcare costs. Therefore, a combinational approach has become a pre-requisite for sustainable medical care. In recent decade, biologically synthesized metallic nanoparticles have emerged as a class of potent antimicrobials. In this study, green synthesized bimetallic silver–copper oxide (Ag–Cu) nanospheres have been prepared using the culture supernatant of the Bacillus subtilis (MTCC 441) bacteria to effectively target infectious microbes. The hydrodynamic diameter of the nanoparticles as depicted by dynamic light scattering (DLS) was 143.5 nm, while the polydispersity index (PI) of 0.367 and zeta potential of −25.2 mV indicated toward uniform size distribution and excellent colloidal stability. The Ag–Cu nanospheres of diameter 22.24 ± 8.01 nm were prepared using the culture supernatant of B. subtilis MTCC 441. High-end techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy revealed the size (22.24 ± 8.01 nm), spherical morphology, crystal structure and surface functionalization of nanospheres, respectively. The antimicrobial potential of the nanospheres was assessed against multidrug-resistant (MDR) bacterial strains while anti-free radical capacity was evaluated through 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and ${\mathrm{\text{H}}}_2{\mathrm{\text{O}}}_2$ free radical inhibition. The anti-inflammatory study was also performed to investigate the biomedical potential of the synthesized Ag–Cu nanosphere. The comprehensive analysis of antimicrobial, anti-oxidative and anti-inflammatory assays presents Ag–Cu nanospheres spheres as suitable candidates to be used in various biomedical applications.