Insight into Biological Effects of Zinc Oxide Nanoflowers on Bacteria: Why Morphology Matters

Large Instrument- and Detergent-Free Assay for Ultrasensitive Nucleic Acids Isolation via Binary Nanomaterial

Nucleic acid-based diagnostics are widely used for clinical applications due to their powerful recognition of biomolecule properties. Isolation and purification of nucleic acids such as DNA and RNA in the diagnostic system have been severely hampered in point-of-care testing because of low recovery yields, degradation of nucleic acids due to the use of chaotropic detergent and high temperature, and the requirement of large instruments such as centrifuges and thermal controllers. Here, we report a novel large instrument- and detergent-free assay via binary nanomaterial for ultrasensitive nucleic acid isolation and detection from cells (eukaryotic and prokaryotic). This binary nanomaterial couples a zinc oxide nanomultigonal shuttle (ZnO NMS) for cell membrane rupture without detergent and temperature control and diatomaceous earth with dimethyl suberimidate complex (DDS) for the capture and isolation of nucleic acids (NA) from cells. The ZnO NMS was synthesized to a size of 500 nm to permit efficient cell lysis at room temperature within 2 min using the biological, chemical, and physical properties of the nanomaterial. By combining the ZnO NMS with the DDS and proteinase K, the nucleic acid extraction could be completed in 15 min with high quantity and quality. For bacterial cells, DNA isolation with the binary nanomaterial yielded 100 times more DNA, than a commercial spin column based reference kit, as determined by the NanoDrop spectrophotometer. We believe that this binary nanomaterial will be a useful tool for rapid and sensitive nucleic acid isolation and detection without large instruments and detergent in the field of molecular diagnostics.

Zinc oxide nanoleaves: A scalable disperser-assisted sonochemical approach for synthesis and an antibacterial application

Current study reports a new and highly scalable method for the synthesis of novel structure Zinc oxide nanoleaves (ZnO-NLs) using disperser-assisted sonochemical approach. The synthesis was carried out in different batches from 50mL to 1L to ensure the scalability of the method which produced almost similar results. The use of high speed (9000rpm) mechanical dispersion while bath sonication (200W, 33kHz) yield 4.4g of ZnO-NLs powder in 1L batch reaction within 2h (>96% yield). The ZnO-NLs shows an excellent thermal stability even at a higher temperature (900°C) and high surface area. The high antibacterial activity of ZnO-NLs against diseases causing Gram-positive bacteria Staphylococcus aureus shows a reduction in CFU, morphological changes like eight times reduction in cell size, cell burst, and cellular leakage at 200µg/mL concentration. This study provides an efficient, cost-effective and an environmental friendly approach for the synthesis of ZnO-NLs at industrial scale as well as new technique to increase the efficiency of the existing sonochemical method. We envisage that this method can be applied to various fields where ZnO is significantly consumed like rubber manufacturing, ceramic industry and medicine.

New Insights into Antibiofilm Effect of a Nanosized ZnO Coating against the Pathogenic Methicillin Resistant Staphylococcus aureus

ZnO nanoparticles (NPs) are arising as promising novel antibiotics toward device-related infections. The surface functionalization of Zn, a novel resorbable biomaterial, with ZnO NPs could present an effective solution to overcome such a threat. In this sense, the antibacterial and antibiofilm activity of nano- and microsized ZnO coatings was studied against clinically relevant bacteria, methicillin resistant Staphylococcus aureus (MRSA). The bacterial viability of planktonic and biofilm cells together with the corresponding biofilm structures revealed that only the nanosized ZnO coating had an antibiofilm effect. To elucidate this effect, a novel approach was taken: preconditioning of bacteria with this ZnO coating followed by exposure to subinhibitory concentrations of antibiotics with well-known modes of actions. This approached revealed (i) a decreased biofilm formation in combination with gentamycin, targeting protein synthesis, and (ii) an increased biofilm formation in the presence of rifampicin and vancomycin, acting on RNA and cell wall biosynthesis, respectively. The increased bacteria resistance to these two antibiotics gave new insights into the antibiofilm effect of this nanosized ZnO coating. The synergistic effect observed for gentamycin opened new perspectives for the design of effective solutions against implant-related infections. During the in vitro degradation of this nanosized ZnO-coated Zn, a specific corrosion product, hopeite [Zn₃(PO₄)₂], was depicted. Interestingly, the increased deposition of hopeite-derived compounds on MRSA cells surface seemed to be related to unhealthy and dead bacterial cells. This observation suggested that hopeite may well play a key role in this antibiofilm activity. The results obtained herein shed light on the possible antibacterial effect of a nanosized ZnO coating, and strengthened its antimicrobial (antibacterial and antifungal) potential, therefore providing a potentially effective material to overcome the growing trend of implant-related infections.

Povidone-Iodine-Based Polymeric Nanoparticles for Antibacterial Applications

As microbial contamination is becoming more and more serious, antibacterial agents play an important role in preventing and removing bacterial pathogens from microbial pollution in our daily life. To solve the issues with water solubility and antibacterial stability of PVP-I₂ (povidone-iodine) as a strong antibacterial agent, we successfully obtain hydrophobic povidone-iodine nanoparticles (povidone-iodine NPs) by a two-step method related to the advantage of nanotechnology. First, the synthesis of poly(N-vinyl-2-pyrrolidone-co-methyl methacrylate) nanoparticles, i.e., P(NVP-MMA) NPs, was controlled by tuning a feed ratio of NVP to MMA. Then, the products P(NVP-MMA) NPs were allowed to undergo a complexation reaction with iodine, resulting in the formation of a water-insoluble antibacterial material, povidone-iodine NPs. It is found that the feed ratio of NVP to MMA has an active effect on morphology, chemical composition, molecular weight, and hydrophilic-hydrophobic properties of the P(NVP-MMA) copolymer after some technologies, such as SEM, DLS, elemental analysis, ¹H NMR, GPC, and the contact angle test, were used in the characterizations. The antibacterial property of povidone-iodine NPs was investigated by using Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Pseudomonas aeruginosa (P. aeruginosa) as model bacteria with the colony count method. Interestingly, three products, such as glue, ink, and dye, after the incorporation of povidone-iodine NPs, show significant antibacterial properties. It is believed that, with the advantage of nanoscale morphology, the final povidone-iodine NPs should have great potential for utilization in various fields where antifouling and antibacterial properties are highly required.

In vivo evaluation of toxicity and antiviral activity of polyrhodanine nanoparticles by using the chicken embryo model

Evaluation of the potential cytotoxicity of polyrhodanine nanoparticles is an important factor for its biological applications. In current study, for the first time histopathological and biochemical analysis of polyrhodanine besides of its antiviral activity against Newcastle disease virus (NDV) were examined on chicken embryo model. Polyrhodanine was synthesized by the chemical oxidative polymerization method. The obtained nanoparticles were characterized by scanning electron microscopy (SEM), and Fourier transform infrared (FTIR). Different doses of polyrhodanine nanoparticles were injected into the albumen in 4-day-old embryonic eggs for groups: (0.1ppm, 1ppm, 10ppm and 100ppm), while the Control group received only normal saline. The gross examination of chicks revealed no abnormality. No pathological changes were detected in microscopical examination of the liver, kidney, spleen, heart, bursa of Fabricius and central nervous system tissues. Blood serum biochemical indices showed no significant differences between control and treatment groups. Interestingly, polyrhodanine nanoparticles showed strong antiviral activity against NDV in ovo. These preliminary findings suggest that polyrhodanine nanoparticles without any toxicity effect could be utilized in controlling Newcastle disease in chickens.

Recent advances in nanomaterials for water protection and monitoring

Nanomaterials (NMs) for adsorption, catalysis, separation, and disinfection are scrutinized. NMs-based sensor technologies and environmental transformations of NMs are highlighted.

Fe2O3 nanoparticles anchored on 2D kaolinite with enhanced antibacterial activity

Fe₂O₃ nanoparticles with different dispersion states on the surface of modified kaolinite were controlled for enhancing antibacterial activity.

Shell thickness-dependent antibacterial activity and biocompatibility of gold@silver core–shell nanoparticles

The Au@Ag NPs exhibit synergistically enhanced antibacterial activity and kill bacteria by affecting the cell membrane integrity or causing cell membrane disruption.