Nano LIFE

Metal and metal oxide nanoparticles are active materials used in water treatment technologies. The emergence of these nanomaterials is due to the increasing demand for clean water supply. Among these nanoscale materials, Silver (Ag) and Zinc oxide (ZnO) are famous for having shown good antibacterial properties, essential in water purification technologies. Aside from its pure metal form, its composites have also been explored due to their synergistic effects with some polymeric matrices. Chitosan, for example, is an abundant natural material for its biodegradability, non-toxicity, and water purification properties. In this review, syntheses of Ag and ZnO nanoparticles together with their composites are discussed. Furthermore, its antibacterial properties, along with its water purification efficiencies, are further analyzed. The authors also give an outlook on the possible directions of nanomaterials in water remediation and the inevitable challenges ahead.

En-bloc tumor resection is the standard treatment for locally advanced colorectal cancer (CRC). An extensive histopathological assessment is necessary to evaluate the metastatic spread and adjuvant therapy. Sentinel lymph node biopsy decreases the histopathological burden when only sentinel lymph nodes (SLNs) are examined. This study aims to evaluate the spread of a magnetic tracer throughout the lymphatic system after ex vivo injection in en-bloc resected specimens of patients with CRC. To achieve this, lymph nodes (LNs) were quantified using a new magnetic detection method. Fifteen patients with CRC diagnosed with clinically negative LNs were included in this study and received 2–4 ex vivo magnetic tracer injections (total volume of 2mL). Magnetic sample series were acquired to create a look-up table for magnetic tracer quantification. In 80% of the patients, at least one magnetic LN was detected. A total of 33 LNs were marked as magnetic, containing an average of 8.1$\mu$g iron. In 71% of the patients, metastases were found in nonmagnetic LNs. Ex vivo injection leads to sub-optimal tracer spread and therefore inaccurate diagnosis. This study presents a novel magnetic detection method to quantify magnetic tracer in lymph nodes. Detecting the SLNs in en-bloc resected specimens and involving only these LNs in histopathological investigation enable a decrease in healthcare costs or an increased diagnostic potential.

Due to their distinct structural, electrical, and electrochemical properties, macrocyclic complexes have been recognized as potential models in a variety of areas, including electrocatalysis, biology, and medicine. In this study, two hexa-aza-macrocyclic complexes of Ni(II) and Cu(II) transition metals (denoted as [NiL] and [CuL]) were synthesized via template procedure. Based on the results of multiple spectroscopic characterization, a distorted octahedral geometry was proposed for both the complexes. The electrochemical results showed that the macrocyclic framework can stabilize the unusual oxidation states of Ni(II) and Cu(II) transition metal ions, as evidenced by the corresponding quasi-reversible Ni(II)/(III) and Cu(II)/(III) redox couples. Additionally, both the complexes were found to be promising antibacterial agents against the B. subtilis, S. aureus, P. aeruginosa, and E. coli pathogens. The Cu(II) complex had the largest inhibition zone (22mm) against B. subtilis, while the Ni(II) complex had the smallest (15mm).

Synthetic protocols for the preparation of nanomaterials chemically are expensive, too much time taking and unfriendly to the environment, therefore, phyto-assisted approach has the potential to be a promising alternative strategy for the synthesis of nanomaterials. Herein, Fe₂O₃ with nanoflower-like architecture (Fe₂O₃ NFs) was prepared using Moringa oleifera leaf extract, and characterized by employing several analytical techniques. The antimicrobial activity of the prepared Fe₂O₃ NFs was evaluated against the bacteria viz. Salmonella typhi, Staphylococcus aureus, Bacillus subtilis, Escherichia coli by using the serial dilution method. The results suggested that Fe₂O₃ NFs possess comparable antimicrobial activity comparable with streptomycin against the used pathogens.

This paper presents the performance of three different micro-electro mechanical systems (MEMS)-based surface acoustic wave (SAW) devices for sensing hydrogen gas. All three devices, namely, Device 1, Device 2 and Device 3, were constructed with the same dimensions but with varying geometries. The devices were simulated using COMSOL Multiphysics and various analyses such as deflection, electric potential, frequency shift with respect to the concentration of hydrogen gas, total capacitance of interdigital transducers (IDTs) and sensitivity were performed using finite element modeling. The devices were constructed with a lithium-niobate piezoelectric substrate and a ZnO sensing layer. The performance of MEMS-based SAW devices can be improved by doping with nanomaterials. The devices were tested with hydrogen gas at concentration from 10ppm to 100ppm. Owing to the mass loading effect, Device 3 exhibited maximum sensitivity and a close approximation of the simulated results with the theoretical results.