Synthesis of Antibacterial Oxide of Copper for Potential Application as Antifouling Agent

Background: Copper oxide nanoparticles have become very important due to their numerous applications and ease of synthesis. Out of the two oxides of copper, cuprous oxide exhibits better antibacterial, antimicrobial, and antifouling properties. Objective: The study aimed to find a way of synthesizing stable and eco-friendly oxide of copper and test it for antibacterial properties. Methods: The precipitation method was employed for the synthesis of nanoparticles. NaOH and Moringa Oleifera leaves extract were used as the reducing agents to obtain two different sets of samples. Results: Good phases of copper oxides were formed for all the samples (cuprous as well as cupric oxides). SEM studies showed that the structure of cupric oxide (CuO), formed at higher calcination temperatures, is well defined when synthesized using a hybrid method. Conclusion: Our studies indicate that the hybrid method of synthesis used by us is a more effective and quicker way of synthesizing cuprous oxide (Cu2O), which exhibits higher antibacterial properties as compared to cupric oxide (CuO).

Synthetic Analogue of Butenolide as an Antifouling Agent

Butenolide derivatives have the potential to be effective and environmentally friendly antifouling agents. In the present study, a butenolide derivative was structurally modified into Boc-butenolide to increase its melting point and remove its foul smell. The structurally modified Boc-butenolide demonstrated similar antifouling capabilities to butenolide in larval settlement bioassays but with significantly lower toxicity at high concentrations. Release-rate measurements demonstrated that the antifouling compound Boc-butenolide could be released from polycaprolactone-polyurethane (PCL-PU)-based coatings to inhibit the attachment of foulers. The coating matrix was easily degraded in the marine environment. The performance of the Boc-butenolide antifouling coatings was further examined through a marine field test. The coverage of biofouler on the Boc-butenolide coatings was low after 2 months, indicating the antifouling potential of Boc-butenolide.

Investigating The Sub-Acute Responses Of Lemna Minor, Pseudokirchneriella Subcapitata, Euglena Gracilis And Anodonta Grandis To Tributyltin-Hydride And Atrazine In Freshwater

Freshwater resources exist in limited quantities and are subject to increasing demands due to the consumption by residential, commercial and industrial uses. There are concerns that the widely used chemical analysis of drinking water does not deliver timely results. This study examines the efficacy of developing a holistic, multi-organism early-warning biomonitoring technology to assess aquatic toxicity. Sensitive indicator species such as Lemna minor, Pseudokirchneriella subcapitata, Euglena gracilis, and Anodonta grandis have been selected due to their specific behavioural and short-term biochemical responses in the identification of classes of contaminants in aquatic environments. Tributyltin, an antifouling agent in paints used on boats and atrazine, an herbicide widely used on agricultural crops, are evaluated in increasing concentrations to identify behavioural changes in these organisms. These graded responses, upon implementation in models, will warn water treatment operators of incoming contaminants and help identify the nature of the stressor. All organisms displayed some sensitivity to selected concentrations of the two test chemicals. The normal growth rate of L. minor dramatically declined with exposure to TBT (100.0 mg/L) and atrazine (500.0 g/L). Monitoring the biochemical changes, dissolved oxygen production, and also the growth rate, cell counts, of P. subcapitata showed significant effects to similar concentrations of TBT (100.00 g/L) and atrazine (500.00 g/L). The aquatic protest, E. gracilis, alters its cell morphology in the presence of low concentrations of TBT (10.0 g/L) and atrazine (50.0 g/L). Respiration patters of the bivalve, A. grandis, was directly influenced by the two chemicals, TBT (1.0 mg/L) and atrazine (50.0 mg/L). This study demonstrates that biological assessments of water samples deliver a rapid, realistic representation of the surrounding aquatic environment conditions.

Investigating The Sub-Acute Responses Of Lemna Minor, Pseudokirchneriella Subcapitata, Euglena Gracilis And Anodonta Grandis To Tributyltin-Hydride And Atrazine In Freshwater

Freshwater resources exist in limited quantities and are subject to increasing demands due to the consumption by residential, commercial and industrial uses. There are concerns that the widely used chemical analysis of drinking water does not deliver timely results. This study examines the efficacy of developing a holistic, multi-organism early-warning biomonitoring technology to assess aquatic toxicity. Sensitive indicator species such as Lemna minor, Pseudokirchneriella subcapitata, Euglena gracilis, and Anodonta grandis have been selected due to their specific behavioural and short-term biochemical responses in the identification of classes of contaminants in aquatic environments. Tributyltin, an antifouling agent in paints used on boats and atrazine, an herbicide widely used on agricultural crops, are evaluated in increasing concentrations to identify behavioural changes in these organisms. These graded responses, upon implementation in models, will warn water treatment operators of incoming contaminants and help identify the nature of the stressor. All organisms displayed some sensitivity to selected concentrations of the two test chemicals. The normal growth rate of L. minor dramatically declined with exposure to TBT (100.0 mg/L) and atrazine (500.0 g/L). Monitoring the biochemical changes, dissolved oxygen production, and also the growth rate, cell counts, of P. subcapitata showed significant effects to similar concentrations of TBT (100.00 g/L) and atrazine (500.00 g/L). The aquatic protest, E. gracilis, alters its cell morphology in the presence of low concentrations of TBT (10.0 g/L) and atrazine (50.0 g/L). Respiration patters of the bivalve, A. grandis, was directly influenced by the two chemicals, TBT (1.0 mg/L) and atrazine (50.0 mg/L). This study demonstrates that biological assessments of water samples deliver a rapid, realistic representation of the surrounding aquatic environment conditions.

Antimicrobial Activity of Photoactive Cerium Doped Zinc Oxide

Biofouling and biofilms exist as ubiquitous, undesirable accumulation of flora and fauna upon a given substrate when being immersed into an aquatic medium. Therefore, a novel antifouling based materials with the incorporation of nanotechnology has been developed for the prevention of biofouling in its initial stage through photocatalytic treatment. This study investigated the antimicrobial properties of photoactive Cerium (Ce) doped ZnO powder and explores its potential properties for future antifouling application. ZnO nanoparticles was doped with 0.4 mol% Ce was synthesized through the combination of modified citrate gelation technique and solid state sintering. The successful preparation of Ce doped ZnO was confirmed by XRD and SEM. The antimicrobial activity of Ce doped ZnO against E. coli and S. aureus was determined through antibacterial susceptibility test by agar well diffusion method whilst its photocatalytic inactivation efficiency against selected bacteria was analysed through photodegradation testing under UV light irradiation. The findings demonstrated that the synthesized Ce doped ZnO powder exhibited antibacterial effect against Gram-positive bacteria (S. aureus) and excellent photocatalytic efficiency to inactivate both Gram-negative (E. coli) and Gram-positive (S. aureus). 2 g/L of Ce doped ZnO catalyzed the 100% disinfection of both bacteria in 180 min of UV light exposure. Thus, this proved that Ce doped ZnO powder has the potential as efficient antifouling agent.

The Grafting of Multifunctional Antithrombogenic Chemical Networks on Polyurethane Intravascular Catheters

Intravascular catheters (IVCs) and other medical tubing are commonly made of polymeric materials such as polyurethane (PU). Polymers tend to be fouled by surface absorption of proteins and platelets, often resulting in the development of bacterial infections and thrombosis during catheterization, which can lead to embolism and death. Existing solutions to fouling are based on coating the IVCs with hydrophilic, anti-thrombogenic, or antimicrobial materials. However, the delamination of the coatings themselves is associated with significant morbidity, as reported by the United States Food and Drug Administration (FDA). We developed a lubricious, antimicrobial, and antithrombogenic coating complex, which can be covalently attached to the surface of industrial PU catheters. The coating complex is pre-synthesized and comprises 2-methacryloyloxyethyl phosphorylcholine (MPC) as an antifouling agent, covalently attached to branched polyethyleneimine (bPEI) as a lubricating agent. The two-step coating procedure involves PU-amine surface activation using a diisocyanate, followed by chemical grafting of the bPEI-S-MPC complex. Compared with neat PU, the coating was found to reduce the coefficient of friction of the IVC surface by 30% and the hemolysis ratio by more than 50%. Moreover, the coating exhibited a significant antimicrobial activity under JIS Z2801:2000 standard compared with neat PU. Finally, in in-vivo acute rabbit model studies, the coating exhibited significant antithrombogenic properties, reducing the thrombogenic potential to a score of 1.3 on coated surfaces compared with 3.3 on uncoated surfaces. The materials and process developed could confer lubricious, antithrombogenic, and antimicrobial properties on pre-existing PU-based catheters.