Broad spectrum antimicrobial activity of functionalized polyanilines

A cathodically polarized PANI-based lead ion-selective electrode: achieving high stability with antibiofouling capabilities

Solid-state contact ion-selective electrodes (SC-ISEs) are an efficacious means of monitoring heavy metal contamination. Instability of the electrode potential is a key factor limiting their development, with biofouling in real water samples posing a significant challenge to maintaining stability. Therefore, addressing biofouling is crucial for optimizing solid-state ion-selective electrodes. In this work, high stability and antibiofouling capability in a solid-state contact lead ion-selective electrode (SC-Pb2+-ISE) based on polyaniline (PANI) was achieved through cathodic polarization. Specifically, PANI played a dual role in the ion-selective membrane (ISM) as an ion-to-electron transducer and antifouling agent. Given the excellent electrochemical performance of PANI, the prepared electrode (GC/PANI-Pb2+-ISM) demonstrated a remarkable antibiofouling efficiency of 98.2% under a cathodic polarization of -0.2 V. Furthermore, a standard deviation of standard potential (Eθ) as low as ± 0.5 mV was realized successfully. The excellent chrono-potentiometric stability of 17.0 ± 2.9 μV/s was also demonstrated. The electrode maintained a Nernstian response slope of 30.7 ± 0.2 (R2 = 0.998) after applying a cathode potential (-0.2 V) for 30 min. The developed GC/PANI-Pb2+-ISM electrode is suitable for practical applications in real environmental water sample monitoring.

Synthesis and characterization of antimicrobial colloidal polyanilines

The potential application of colloidal polyaniline (PANI) as an antimicrobial is limited by challenges related to solubility in common organic solvents, scalability, and antimicrobial potency. To address these limitations, we introduced a functionalized PANI (fPANI) with carboxyl groups through the polymerisation of aniline and 3-aminobenzoic acid in a 1:1 molar ratio. fPANI is more soluble than PANI which was determined using a qualitative study. We further enhanced the solubility and antimicrobial activity of fPANI by incorporating Ag nanoparticles onto the synthesized fPANI colloid via direct addition of 10 mM AgNO3. The improved solubility can be attributed to an approximately 3-fold reduction in size of particles. Mean particle sizes are measured at 1322 nm for fPANI colloid and 473 nm for fPANI-Ag colloid, showing a high dispersion and deagglomeration effect from Ag nanoparticles. Antimicrobial tests demonstrated that fPANI-Ag colloids exhibited superior potency against Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli, and Bacteriophage PhiX 174 when compared to fPANI alone. The minimum bactericidal concentration (MBC) and minimum virucidal concentration (MVC) values were halved for fPANI-Ag compared to fPANI colloid and attributed to the combination of Ag nanoparticles with the fPANI polymer. The antimicrobial fPANI-Ag colloid presented in this study shows promising results, and further exploration into scale-up can be pursued for potential biomedical applications.

Multifunctional polyaniline modified calcium alginate aerogel membrane with antibacterial, oil-water separation, dye and heavy metal ions removal properties for complex water purification

With the rapid development of urbanization, the discharge of industrial wastewater has led to increasingly critical water pollution issues. Additionally, heavy metals, organic dyes, microorganisms and oil pollution often coexist and have persistence and harmfulness. Developing materials that can treat these complex pollutants simultaneously has important practical significance. In this study, a calcium alginate-based aerogel membrane (PANI@CA membrane) was prepared by spraying, polymerization, Ca2+ cross-linking and freeze-drying using aniline and sodium alginate as raw materials. Oil-water emulsion can be separated by PANI@CA membrane only under gravity, and the separation efficiency was as high as 99 %. At the same time, the membrane can effectively intercept or adsorb organic dyes and heavy metal ions. The removal rates of methylene blue and Congo red were above 92 % and 63 % respectively even after ten times of cyclic filtration. The removal rate of Pb2+ was up to 95 %. In addition, PANI@CA membrane shows excellent photothermal conversion ability, and it can effectively kill Staphylococcus aureus under 808 nm laser irradiation. PANI@CA membrane has the advantages of low cost, simple preparation, good stability and high recycling ability, and has potential application prospects in wastewater treatment.

Polyrhodanine-based nanomaterials for biomedical applications: A review

Rhodanine is a heterocyclic organic compound that has been investigated for its potential biomedical applications, particularly in drug discovery. Rhodanine derivatives have been examined as the medication options for numerous illnesses, including cancer, inflammation, and infectious diseases. Some rhodanine derivatives have also shown promising activity against drug-resistant strains of bacteria and viruses. One of these derivatives is polyrhodanine (PR), a conducting polymer that has gained attention for its biomedical properties. This review article summarises the latest advancements in creating biomaterials based on PR for biosensing, antimicrobial treatments, and anticancer therapies. The distinctive characteristics of PR, such as biocompatibility, biodegradability, and good conductivity, render it an attractive candidate for these applications. The article also explores obstacles and potential future paths for advancing biomaterials made with PR, including synthesis modifications, characterisation techniques, and in vivo evaluation of biocompatibility and efficacy. Overall, as an emerging research topic, this review emphasises the potential of PR as a promising biomaterial for various biomedical applications and provides insights into the contemporary state of research and prospective directions for investigation.

Anthraquinone-Polyaniline-Integrated Textile Platforms for In Situ Electrochemical Production of Hydrogen Peroxide for Microbial Deactivation

Hydrogen peroxide (H₂O₂) is a versatile and effective disinfectant against common pathogenic bacteria such as Escherichia coli (E. coli). Electrochemical H₂O₂ generation has been studied in the past, but a lack of studies exists on miniaturized electrochemical platforms for the on-demand synthesis of H₂O₂ for antibacterial applications. In this article, a chemically modified cotton textile platform capable of in situ H₂O₂ production is demonstrated for E. coli deactivation. The cotton textile was modified by layer-by-layer coating with conductive carbon nanotubes/cellulose nanocrystals (CNT/CNC) and a polymer of polyaniline (PANI) decorated with anthraquinone (AQ), designated as the AQ@PANI@CNT/CNC@textile antibacterial patch. The AQ@PANI@CNT/CNC@textile antibacterial textile patch H₂O₂ production capabilities were evaluated using both electrochemical and colorimetric methods. The AQ@PANI@CNT/CNC@textile antibacterial patch electrochemically produced H₂O₂ concentrations up to 209 ± 25 µM over a 40 min period and displayed a log reduction of 3.32 for E. coli over a period of 2 h. The AQ@PANI@CNT/CNC@textile antibacterial patch offers promise for use as a self-disinfecting pathogen control platform.

Intrinsic Light-Activated Oxidase Mimicking Activity of Conductive Polyaniline Nanofibers: A Class of Metal-Free Nanozyme

In recent decades, studies have focused on inorganic nanozymes to overcome the intrinsic drawbacks of bioenzymes due to the demands of improving the reaction conditions and lack of robustness to harsh environmental factors. Many biochemical reactions catalyzed by enzymes require light activation. Light-activated nanozymes have distinct advantages, including being regulated by light stimuli, activating the molecular oxygen to produce reactive oxygen species (ROS) without interfering supplementary oxidants, and often showing a synergistic effect to catalyze some challenging reactions. Only a few studies have been done on this connection. Therefore, it is still a big challenge to develop a nanozyme regulated by light activation. Herein, we uncovered the light-activated oxidase mimicking activity of a conducting polymer polyaniline nanofibers (PANI-NFs). PANI-NFs exhibit intrinsic light-activated brilliant oxidase-like activity, can catalyze the colorless tetramethyl benzidine (TMB) to produce a blue product TMBox, and have a distinct K_m = 0.087 mM and a high V_max = 2.32 μM min^-1 value, measured by using Hanes-Woolf kinetics. We also report the light-activated oxidase activity of some other renowned carbocatalysts graphene oxide and graphitic carbon nitride and compare them with PANI-NFs. This type of property shown by the conductive polymer is amazing. The density functional theory is used to verify the stability and the mode of adsorption of the PANI NFs-TMB composite, which corroborates the experimental results. Furthermore, the current nanozyme demonstrated a significant ability to kill both Gram-negative and Gram-positive bacteria as well as effectively destroy biofilms under physiological conditions. We believe that this work provides the motivation to create a link between optoelectronics and biological activity in the near future.

Anticancer potential of poly(2-aminobenzoic acid)-blend-Aloe vera against the human breast cancer cell line MDA-MB-231

Breast cancer in women is amongst the most significant concerns from time immemorial in the field of oncology. This study proposes an anticancerous polymeric material based on an electroactive substituted polyaniline blend, poly(2-aminobenzoic acid)-blend-Aloe vera (PABA/AV) synthesized by the emulsion polymerization method. The structural, thermal, and morphological characteristics determined using FT-IR and UV-Visible Spectroscopy, XRD, TGA, DTA, and SEM-EDX validated the thermally stable, semi-crystalline, emeraldine salt structure. The material is semi-conducting, and the electrical conductivity measured is 1.86 × 10−3 S/cm. It shows bactericidal efficacy against Enterococcus faecalis at a minimum inhibitory and minimum bactericidal concentration of 50 μg/mL. The radical cations in the emeraldine polymer chain reduce the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and exhibit a significant % of DPPH scavenging (89.85%) at 20 μL. The polymer blend is active against the human breast cancer cell line MDA-MB-231 and causes 78.65% cytotoxicity at a concentration of 125 μg/mL. The synergistic effect of the ancient healing Aloe vera plant and the electroactive biocompatible poly(2-aminobenzoic acid) certainly opens up new developments in the field of cancer therapy.

A novel single-step anodization approach for PANI-doping oxide surfaces to improve the photocatalytic activity of titanium implants

Crystalline titanium oxides have shown photocatalytic activity (PCA) and the formation of antibacterial reactive oxygen species (ROS) when stimulated with UV light. Polyaniline (PANI) is a conductive polymer that has shown antibacterial effects. Previously, titanium oxides have been PANI-doped using a multi-step approach. In the present study, we compared PANI-doped specimens produced with a two-step method (ACV), to PANI-doped specimens produced by a novel single-step direct anodization (AAn) method, and a control group of anodized un-doped specimens. The surface morphology, oxide crystallinity, surface elemental composition, surface roughness, surface wettability, oxide adhesion, corrosion resistance, PCA, and ROS generation of each oxide group were evaluated. All groups exhibited mixed anatase and rutile phase oxides. The AAn group revealed less anatase and rutile, but more PANI-surface coverage. The AAn group exhibited significantly increased PCA after 60 minutes of direct UVA illumination compared to the ACV group, despite containing lower amounts of anatase and rutile. The ACV and AAn groups showed significant increases in ROS production after 4 hours UVA illumination while the control group showed similar ROS production. These findings suggested that PANI doping using the novel direct anodization technique significantly improved PCA even for oxides containing less crystallinity. The S. aureus attachment response to each oxide group was also compared under UVA pre-illumination, UVA direct illumination, and no illumination (dark) lighting conditions. Although no significant differences were shown in the bacterial response, both PANI-doped groups exhibited less average bacterial attachment compared to the control group. The response of MC3T3-E1 pre-osteoblast cells to each oxide group was evaluated using MTT and live/dead assays, and no evidence of cytotoxicity was found. Since many, if not most, titanium implant devices are routinely anodized as a part of the manufacturing processes, these study findings are applicable to a wide variety of implant applications.

Enzymatically Synthesized Polyaniline Doped with Copper Ions: Physico-Chemical and Antimicrobial Properties of the Product

Enzymatic synthesis of the polyaniline (PANI)/sodium polystyrenesulfonate (PSS) interpolyelectrolyte complex, in which PANI is doped with Cu(II) ions, has been developed. The biocatalyst for aniline (ANI) polymerization was the fungal laccase Trametes hirsuta and the oxidizing agent was atmospheric oxygen. The resulting PANI-Cu/PSS complex was studied by UV–visible and FTIR-ATR spectroscopy, and X-ray fluorescence analysis. The copper content in PANI‑Cu/PSS was ~8 wt %. The minimum inhibitory concentration (MIC) of the PANI-Cu/PSS complex against gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria was 2.65 and 0.66 mg/mL, respectively.

Betaine-Based Deep Eutectic Solvent as a New Media for Laccase-Catalyzed Template-Guided Polymerization/Copolymerization of Aniline and 3-Aminobenzoic Acid

Deep eutectic solvents (DESs) can compensate for some of the major drawbacks of traditional organic solvents and ionic liquids and meet all requirements of green chemistry. However, the potential of their use as a medium for biocatalytic reactions has not been adequately studied. In this work we used the DES betaine-glycerol with a molar ratio of 1:2 as co-solvent for enzymatic template-guided polymerization/copolymerization of aniline (ANI) and 3-aminobenzoic acid (3ABA). The laccase from the basidial fungus Trametes hirsuta and air oxygen served as catalyst and oxidant, respectively. Sodium polystyrene sulfonate (PSS) was used as template. Interpolyelectrolyte complexes of homopolymers polyaniline (PANI) and poly(3-aminobenzoic acid) (P3ABA) and copolymer poly(aniline-co-3-aminobenzoic acid) (P(ANI-3ABA)) were prepared and their physico-chemical properties were studied by UV-Vis and FTIR spectroscopy and cyclic voltammetry. According to the results obtained by atomic force microscopy, PANI/PSS had a granular shape, P(ANI-3ABA)/PSS had a spherical shape and P3ABA/PSS had a spindle-like shape. The copolymer showed a greater antimicrobial activity against Escherichia coli and Staphylcocus aureus as compared with the homopolymers. The minimal inhibitory concentration of the P(ANI-3ABA)/PSS against the gram-positive bacterium S. aureus was 0.125 mg mL⁻¹.

Assessment of self-doped poly (5-nitro-2-orthanilic acid) as a scaling inhibitor to control the precipitation of CaCO3 and CaSO4 in solution

Self-doped- and nitro-polyanilines have become a widely used strategy to optimize the electronic and vibratory spectra of polymeric building blocks in various applications. We report the synthesis of poly (5-nitro-2-orthanilic acid) by an aniline-initiated oxidative polymerization reaction. The polymer is characterized by spectroscopic techniques, elemental shapes, cyclic voltammetry, electrical conductivity, and microscopic and thermal measurements. The hydrophilic and hydrophobic nature of the supports provided the formation of amphiphilicity as judged by SEM. Thermogravimetric measurements reveal thermal stability up to 500 °C and glass temperature (T_g) observed at 240 °C. Electrical conductivity decreases as the temperature rises at the different frequencies used, reflecting the semiconducting nature in the extrinsic range, which is characterized by high carriers and low mobility. The presence of these electron residues causes a decrease in efficiency and increases the thermal conductivity. Dielectric measurements have shown that permittivity decreases gradually at lower levels, mainly due to the transport of charging carriers, resulting in higher performance. The testing of the copolymer as a new scale blocker has resulted in moderate to fairly high performance. This effect is attributed to the change in polymer geometry using intramolecular H-bonding group -SO₃H and a chain polymer in an aqueous medium.

Synthesis and assessment of poly(5-nitro-2-aminophenol) as a new scaling inhibitor to control the precipitation of CaCO3 and CaSO4 in solution

The introduction of a -NO2 substituent in o-aminophenol would create an open-unit polymer suitable for different applications. We report the synthesis of poly(5-nitro-2-aminophenol) by aniline-catalyzed oxidative polymerization. The polymer structure was intensively characterized by spectroscopic techniques, elemental analysis, cyclic voltammetry, electrical conductivity and microscopic measurements such as SEM, TEM, TGA and DSC. The hydrophilic and hydrophobic nature of the substituents provided the formation of amphiphilicity, as judged by SEM. Thermal measurements reveal high stability up to 500 °C. Electrical conductivity decreases with increasing temperature at various frequencies. This behavior reflects the semiconducting nature in the extrinsic range, which is characterized by high carriers and low mobility. Dielectric measurements have shown that permittivity decreases gradually at lower levels, mainly due to the transport of charging carriers. Investigating the copolymer as a new scale blocker has resulted in moderate to high performance attributed to the change in polymer geometry because of the presence of different tautomers having equivalent ortho functionalities and could equally coordinate with free calcium ions and thus reduce the nucleation rate and block crystal growth. Thus, the abovementioned features indicate a new potential candidate for application as a scaling inhibitor of CaSO4 and CaCO3 precipitation, a common problem in industry.

Antibacterial Activity of Polyaniline Coated in the Patterned Film Depending on the Surface Morphology and Acidic Dopant

We have fabricated poly(ε-caprolactone) (PCL) films with flat and honeycomb-patterned (HCP) structures to coat polyaniline (PANI) on the film surface. In addition, the effect of chemical modification of PANI by sulfuric acid (H2SO4) was also studied for antibacterial activity. The flat and HCP PCL films were obtained by simple evaporation of the solvent and via the breath figure (BF) method, respectively. The morphology and chemical composition of PANI coated on the film surface were evaluated by scanning electron microscopy (SEM) and X-ray spectroscopy (EDX). Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analyses (TGA) were obtained to identify the PANI coating. The wettability and conductivity of the films were also measured. Applicational aspects were evaluated by assessing antibacterial and antibiofilm activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The EDX, TGA, and FT-IR findings indicated chemical modification of PCL film by PANI and H2SO4. The conductivity of the films was increased by the coating of PANI to the patterned surface and additionally increased by the chemically modified PANI. The antibacterial activity was 69.79%, 78.27%, and 88% against E. coli, and 32.73%, 62.65%, and 87.97% against S. aureus, for flat PANI, HCP PANI, and H2SO4-treated HCP films, respectively. Likewise, the PANI coated flat, HCP, and H2SO4-treated HCP films inhibited E. coli biofilm formation by around 41.62%, 63%, and 83.88% and S. aureus biofilm formation by 17.81%, 69.83%, and 96.57%, respectively. The antibacterial activity of the HCP film was higher than that of flat PANI films, probably due to the higher coating of PANI on the HCP surface. Moreover, sulfonation of the HCP film with H2SO4 might have improved the wettability, thereby enhancing the antibacterial and antibiofilm properties. Our results showed that topographical changes, as well as doping, offer simple and cost-effective ways to modify the structural and functional properties of films.

Recent Advancement of the Current Aspects of g-C3 N4 for its Photocatalytic Applications in Sustainable Energy System

Being one of the foremost enticing and intriguing innovations, heterogeneous photocatalysis has also been used to effectively gather, transform, and conserve sustainable sun's radiation for the production of efficient and clean fossil energy as well as a wide range of ecological implications. The generation of solar fuel-based water splitting and CO₂ photoreduction is excellent for generating alternative resources and reducing global warming. Developing an inexpensive photocatalyst can effectively split water into hydrogen (H₂ ), oxygen (O₂ ) sources, and carbon dioxide (CO₂ ) into fuel sources, which is a crucial problem in photocatalysis. The metal-free g-C₃ N₄ photocatalyst has a high solar fuel generation potential. This review covers the most recent advancements in g-C₃ N₄ preparation, including innovative design concepts and new synthesis methods, and novel ideas for expanding the light absorption of pure g-C₃ N₄ for photocatalytic application. Similarly, the main issue concerning research and prospects in photocatalysts based g-C₃ N₄ was also discussed. The current dissertation provides an overview of comprehensive understanding of the exploitation of the extraordinary systemic and characteristics, as well as the fabrication processes and uses of g-C₃ N₄ .

Organic Bioelectronics for In Vitro Systems

Bioelectronics have made strides in improving clinical diagnostics and precision medicine. The potential of bioelectronics for bidirectional interfacing with biology through continuous, label-free monitoring on one side and precise control of biological activity on the other has extended their application scope to in vitro systems. The advent of microfluidics and the considerable advances in reliability and complexity of in vitro models promise to eventually significantly reduce or replace animal studies, currently the gold standard in drug discovery and toxicology testing. Bioelectronics are anticipated to play a major role in this transition offering a much needed technology to push forward the drug discovery paradigm. Organic electronic materials, notably conjugated polymers, having demonstrated technological maturity in fields such as solar cells and light emitting diodes given their outstanding characteristics and versatility in processing, are the obvious route forward for bioelectronics due to their biomimetic nature, among other merits. This review highlights the advances in conjugated polymers for interfacing with biological tissue in vitro, aiming ultimately to develop next generation in vitro systems. We showcase in vitro interfacing across multiple length scales, involving biological models of varying complexity, from cell components to complex 3D cell cultures. The state of the art, the possibilities, and the challenges of conjugated polymers toward clinical translation of in vitro systems are also discussed throughout.

Organic Photo-antimicrobials: Principles, Molecule Design, and Applications

The emergence of multi-drug-resistant pathogens threatens the healthcare systems world-wide. Recent advances in phototherapy (PT) approaches mediated by photo-antimicrobials (PAMs) provide new opportunities for the current serious antibiotic resistance. During the PT treatment, reactive oxygen species or heat produced by PAMs would react with the cell membrane, consequently leaking cytoplasm components and effectively eradicating different pathogens like bacteria, fungi, viruses, and even parasites. This Perspective will concentrate on the development of different organic photo-antimicrobials (OPAMs) and their application as practical therapeutic agents into therapy for local infections, wound dressings, and removal of biofilms from medical devices. We also discuss how to design highly efficient OPAMs by modifying the chemical structure or conjugating with a targeting component. Moreover, this Perspective provides a discussion of the general challenges and direction for OPAMs and what further needs to be done. It is hoped that through this overview, OPAMs can prosper and will be more widely used for microbial infections in the future, especially at a time when the global COVID-19 epidemic is getting more serious.

Microbial inhibition and biosensing with multifunctional carbon dots: Progress and perspectives

Carbon dots (CDs) and their doped counterparts including nitrogen-doped CDs (N@CDs) have been synthesized by bottom-up or top-down approaches from different precursors. The attractiveness of such emerging 2D‑carbon-based nanosized materials is attributed to their excellent biocompatibility, preparation, aqueous dispersibility, and functionality. The antimicrobial, optical, and electrochemical properties of CDs have been advocated for two important biotechnological applications: bacterial eradication and sensing/biosensing. CDs as well as N@CDs act as antimicrobial agents as their surfaces encompass functional hydroxyl, carboxyl, and amino groups that generate free radicals. As a new class of photoluminescent nanomaterials, CDs can be employed in diversified analytics. CDs with surface carboxyl or amino groups form nanocomposites with nanomaterials or be conjugated with biorecognition molecules toward the development of sensors/biosensors. The deployment of conductive CDs in electrochemical sensing has also increased significantly because of their quantum size, excellent biocompatibility, enzyme-mimicking activity, and high surface area. The review also addresses the ongoing challenges and promises of CDs in pathogenesis and analytics. Perspectives on the future possibilities include the use of CDs in microbial viability assay, wound healing, antiviral therapy, and medical devices.

Thermochromic Polymeric Films for Applications in Active Intelligent Packaging-An Overview

The need for passive sensors to monitor changes in temperature has been critical in several packaging related applications. Most of these applications involve the use of bar codes, inks and equipment that involve constant complex electronic manipulation. The objective of this paper is to explore solutions to temperature measurements that not only provide product information but also the condition of the product in real time, specifically shelf-life. The study will explore previously proposed solutions as well as plans for modified approaches that involve the use of smart polymers as temperature sensors.

Nanoengineered Peptide-Based Antimicrobial Conductive Supramolecular Biomaterial for Cardiac Tissue Engineering

Owing to their dynamic nature and ordered architecture, supramolecular materials strikingly resemble organic components of living systems. Although short-peptide self-assembled nanostructured hydrogels are regarded as intriguing supramolecular materials for biotechnology, their application is often limited due to their low stability and considerable challenge of combining other desirable properties. Herein, a di-Fmoc-based hydrogelator containing the cell-adhesive Arg-Gly-Asp (RGD) fragment that forms a mechanically stable, self-healing hydrogel is designed. Molecular dynamics simulation reveals the presence of RGD segments on the surface of the hydrogel fibers, highlighting their cell adherence capacity. Aiming to impart conductivity, the 3D network of the hydrogel is further nanoengineered by incorporating polyaniline (PAni). The composite hydrogels demonstrate semiconductivity, excellent antibacterial activity, and DNA binding capacity. Cardiac cells grown on the surface of the composite hydrogels form functional synchronized monolayers. Taken together, the combination of these attributes in a single hydrogel suggests it as an exceptional candidate for functional supramolecular biomaterial designed for electrogenic tissue engineering.

Polymerization of new aniline derivatives: synthesis, characterization and application as sensors

This work is focused on modifying aniline monomers with various characteristics that allows one to study the effect of the substituent on the respective polymer. A series of new polyaniline (PANI) derivatives based on an ortho-substituted aniline derivative, 2-(1-methylbut-2-en-1-yl)aniline, were synthesized and characterized. The structures and composition of the polymers that we synthesized were confirmed by elemental analysis, proton nuclear magnetic resonance (1H NMR) spectroscopy, carbon nuclear magnetic resonance (13C NMR) spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), and ultraviolet-visible spectroscopy (UV). Characterization by FT-IR and UV-visible spectroscopy techniques indicated that the polymers exist in protonated emeraldine forms. Scanning electron microscope (SEM) results revealed that the surface morphology of the resulting polymers changed from a heterogeneous hierarchical to spherical structure upon changing the substituent in the aniline monomers. The polymers are soluble in common organic solvents, so they can be used to make films. The electrical properties of the polymers were studied and their high sensitivity to moisture and ammonia was demonstrated. The results of the studies showed the prospects of using thin polymer films in the design of chemical sensors. The impact of the substituent on the polymer characteristics is rationalized in terms of steric and electronic effects.

Design and characterization of PANI/starch/Fe2O3 bio composite for wastewater remediation

A new synthesized polyaniline/starch/hematite bio composite (PANI/S/Fe₂O₃ BC) has been studied as an effective material for on-site water remediation. PANI/S/Fe₂O₃ BC was developed by combining the techniques of co-precipitation and interfacial polymerization in the presence of aqueous starch solution in an acidic medium under ultrasonic irradiation. The nano-morphologies and structures of the designed PANI/S/Fe₂O₃ BC were evaluated by various techniques relative to PANI and Fe₂O₃ nanoparticles. In single and multiple systems, PANI/S/Fe₂O₃ BC was evaluated as a possible adsorbent for different heavy metals, including As³⁺, Zn²⁺, and Co²⁺, relative to PANI and Fe₂O₃ nanoparticles. In terms of pH value, operating temperature, initial heavy metal concentration, contact time, adsorbent dose and competitive ions in the solutions, the adsorption process was optimized. For 92% overall adsorption of Co²⁺ and 100% overall adsorption of both As³⁺ and Zn²⁺, the adsorption equilibrium was achieved within 60 and 120 min, respectively. In addition, adsorption thermodynamic analysis shows that the As³⁺ ions adsorption process was not random and the pseudo-second-order fitted with experimental results. Moreover, PANI/S/Fe₂O₃ BC was evaluated as an antibacterial agent against Gram-negative bacteria (Salmonella typhimurium) and Gram-positive bacteria (S. aureus, Methicillin-Resistant Staphylococcus, Aureus Clinical isolate and Bacillus subtilis). The reported performances indicated that the PANI/S/Fe₂O₃ BC is a potent candidate for industrial water bioremediation.

Synthesis of gold nanoparticles/polyaniline boronic acid/sodium alginate aqueous nanocomposite based on chemical oxidative polymerization for biological applications

Gold nanoparticles/polyaniline boronic acid/sodium alginate aqueous nanocomposite ((PABA-SAL)@AuNPs) was fabricated. Aniline boronic acid (ABA) served as reductant of gold salt, all within the SAL solution. While ABA reduced gold salt to its nanoparticles, the ABA monomer was also oxidized to its conducting polymeric form (PABA). The presence of PABA in the reaction mixture exerted solubility and stability challenge, thus SAL was used as stabilizer and solubilizer for PABA. The numerous cis-diol groups of SAL could bind to boronic acid groups of PABA to furnish PABA-SAL repeating polymer structure for AuNPs anchoring. Sparkling ruby red (PABA-SAL)@AuNPs have absorption peaks at 529 and 718 nm. Average particle sizes of nanocomposite were within 15-20 nm, with hydrodynamic diameter of 48.6 ± 0.9 nm, zeta potential of -32.5 ± 1.6 mV and conductivity value of 2015.3 ± 3.2 μS/cm. (PABA-SAL)@AuNPs possessed antibacterial activities against seafood associated bacterial isolates, with MIC and MBC ranging from 4 to 8 μg/mL. The moderate antioxidant capacity of (PABA-SAL)@AuNPs was observed, without any deleterious damages on human red blood cells. It also has good biocompatibility on Caco-2 and RAW 264.7, with cell viability not less than 70%. These results confirm the high prospect of (PABA-SAL)@AuNPs for possible biomedical applications.

Potential Applications of Conducting Polymers to Reduce Secondary Bacterial Infections among COVID-19 Patients: a Review

The COVID-19 pandemic is a motivation for material scientists to search for functional materials with valuable properties to alleviate the risks associated with the coronavirus. The formulation of functional materials requires synergistic understanding on the properties of materials and mechanisms of virus transmission and disease progression, including secondary bacterial infections that are prevalent in COVID-19 patients. A viable candidate in the struggle against the pandemic is antimicrobial polymer, due to their favorable properties of flexibility, lightweight, and ease of synthesis. Polymers are the base material for personal protective equipment (PPE), such as gloves, face mask, face shield, and coverall suit for frontliners. Conducting polymers (CPs) are polymers with electrical properties due to the addition of dopant in the polymer structure. The conductivity of polymers augments their antiviral and antibacterial properties. This review discusses the types of CPs and how their properties could be exploited to ward off bacterial infections in hospital settings, specifically in cases involving COVID-19 patients. This review also covers common CPs fabrication techniques. The key components to produce CPs at several possibilities to fit the current needs in fighting secondary bacterial infections are also discussed.

Antibacterial and Antiviral Functional Materials: Chemistry and Biological Activity toward Tackling COVID-19-like Pandemics

The ongoing worldwide pandemic due to COVID-19 has created awareness toward ensuring best practices to avoid the spread of microorganisms. In this regard, the research on creating a surface which destroys or inhibits the adherence of microbial/viral entities has gained renewed interest. Although many research reports are available on the antibacterial materials or coatings, there is a relatively small amount of data available on the use of antiviral materials. However, with more research geared toward this area, new information is being added to the literature every day. The combination of antibacterial and antiviral chemical entities represents a potentially path-breaking intervention to mitigate the spread of disease-causing agents. In this review, we have surveyed antibacterial and antiviral materials of various classes such as small-molecule organics, synthetic and biodegradable polymers, silver, TiO2, and copper-derived chemicals. The surface protection mechanisms of the materials against the pathogen colonies are discussed in detail, which highlights the key differences that could determine the parameters that would govern the future development of advanced antibacterial and antiviral materials and surfaces.

Study of the effect of band gap and photoluminescence on biological properties of polyaniline/CdS QD nanocomposites based on natural polymer

In this work, band gap, photoluminescence and biological properties of new bionanocomposites based on polyaniline (PANi)/hydrolyzed pectin (HPEc)/cadmium sulfide (CdS) QD nanoparticles (NPs) were studied. In order to improve the morphology and properties, CdS NPs were modified with epichlorohydrin to obtain the modified CdS (mCdS). The CdS@HPEc-g-PANi and mCdS@HPEc-g-PANi samples were synthesized via heterogeneous chemical polymerization and characterized by FTIR, ¹HNMR, SEM/XRD, EDX/TEM/EDX-mapping and TGA analyses. The objective of this work is the study of physical, optical and cytotoxicity properties of the nanocomposites and comparison between them. The SEM, XRD and TGA images showed that the modification of NPs resulted in homogeneous morphology, increase of crystalline structure and high thermal stability which influenced on physical and biological property. According to UV-DRS analysis, the mCdS@HPEc-g-PANi indicated lower energy gap compared to the CdS@HPEc-g-PANi nancomposite. The presence of conductive polymer and synergy effect between the PANi and CdS caused higher PL intensity in the CdS@HPEc-g-PANi nanocomposite compared to pure CdS. The emission intensity in the mCdS@HPEc-g-PANi nanocomposite was reduced since the organic modifying agent cause reducing emission intensity. The mCdS@HPEc-g-PANi nanocomposite, due to more compatibility of organic agent with cellular walls of biological cells that help to the diffusion of metal CdS NPs into cell tissue indicated more toxicity effect on cell growth.

Integrated meta-analysis and machine learning approach identifies acyl-CoA thioesterase with other novel genes responsible for biofilm development in Staphylococcus aureus

Biofilm forming Staphylococcus aureus is a major threat to the health-care industry. It is important to understand the differences between planktonic and biofilm growth forms in the pathogen since conventional treatments targeting the planktonic forms are not effective against biofilms. The current study conducts a meta-analysis of three public transcriptomic profiles to examine the differences in gene expression between the planktonic and biofilm states of S. aureus using random-effects modeling. Mean effect sizes were calculated for 2847 genes among which 726 differentially expressed genes were taken for further analysis. Major genes that are discriminatory between the two conditions were mined using supervised learning techniques and validated by high-accuracy classifiers. Ten different feature selection algorithms were applied and used to rank the most important genes in S. aureus biofilms. Finally, an optimal set of 36 genes are presented as candidate genes in biofilm formation or development while throwing light on the novel roles of an acyl-CoA thioesterase enzyme and 10 hypothetical proteins in biofilms. The relevance of the identified gene set was further validated by building five different classification models using SVM, RF, kNN, NB and DT algorithms that were compared with models built from other relevant gene sets and by reviewing the functional role of 25 previously known genes in biofilm development. The study combines meta-analysis of differential expression with supervised machine learning strategies and feature selection for the first time to identify and validate a discriminatory set of genes important in biofilms of S. aureus. The functional roles of the identified genes predicted to be important in biofilms are further scrutinized and can be considered as a signature target list to develop anti-biofilm therapeutics in S. aureus.

Conjugated polymer nanostructures displaying highly photoactivated antimicrobial and antibiofilm functionalities

This work reports the use of conjugated polymer nanostructures (CPNs) as photoactivated antimicrobial compounds against Gram-positive and Gram-negative microorganisms. Two representative CPNs of polythiophene (PEDOT) and polyaniline (PANI) were prepared as nanofibres with an average diameter of 40 nm and length in the micrometer range. Both CPNs exhibited strong antimicrobial activity under UVA irradiation with the same fluence rate as the UVA component of the solar spectrum. The effect was tested using the Gram-positive bacteria Staphylococcus aureus and the Gram-negative bacteria Escherichia coli. The reduction of colony forming units (CFUs) reached >6 log for PEDOT concentrations as low as 33 ng mL-1. For PEDOT nanofibers, a complete inhibition of S. aureus and E. coli growth was reached at 883 ng mL-1 and 333 ng mL-1 respectively. The photoactivation effect of PANI nanofibres on S. aureus and E. coli was also high, with a CFU reduction of about 7 log and 4 log respectively for an exposure concentration of 33 ng mL-1. The antimicrobial activity was only high under light irradiation and was almost negligible for bulk PEDOT and PANI. The effect of polymeric nanofibers could be attributed to the photoinduced generation of reactive oxygen species, which may induce cell membrane damage, eventually leading to bacterial impairment and inhibition of their biofilm forming capacity. CPN PEDOT and PANI coatings were able to keep surfaces free of bacterial attachment and growth even after 20 h of previous contact with exponentially growing cultures in the dark. PEDOT and PANI CPNs demonstrated good cytocompatibility with human fibroblasts and the absence of hemolytic activity. The materials demonstrated advantages in terms of broad antibacterial spectrum, biofilm inhibition, and the absence of acute toxicity for biomedical applications.

Dye Separation and Antibacterial Activities of Polyaniline Thin Film-Coated Poly(phenyl sulfone) Membranes

We fabricated a nanofiltration membrane consisting of a polyaniline (PANI) film on a polyphenylsulfone (PPSU) substrate membrane. The PANI film acted as a potent separation enhancer and antimicrobial coating. The membrane was analyzed via scanning electron microscopy and atomic force microscopy to examine its morphology, topography, contact angle, and zeta potential. We aimed to investigate the impact of the PANI film on the surface properties of the membrane. Membrane performance was then evaluated in terms of water permeation and rejection of methylene blue (MB), an organic dye. Coating the PPSU membrane with a PANI film imparted significant advantages, including finely tuned nanometer-scale membrane pores and tailored surface properties, including increased hydrophilicity and zeta potential. The PANI film also significantly enhanced separation of the MB dye. The PANI-coated membrane rejected over 90% of MB with little compromise in membrane permeability. The PANI film also enhanced the antimicrobial activity of the membrane. The bacteriostasis (B R) values of PANI-coated PPSU membranes after six and sixteen hours of incubation with Escherichia coli were 63.5% and 95.2%, respectively. The B R values of PANI-coated PPSU membranes after six and sixteen hours of incubation with Staphylococcus aureus were 70.6% and 88.0%, respectively.

Antimicrobial effects of positively charged, conductive electrospun polymer fibers

In recent years, electrospun polymer fibers have gained attention for various antibacterial applications. In this work, the effect of positively charged polymer fiber mats as antibacterial gauze is studied using electrospun poly(caprolactone) and polyaniline nanofibers. Chloroxylenol, an established anti-microbial agent is used for the first time as a secondary dopant to polyaniline during the electrospinning process to make the surface of the polyaniline fiber positively charged. Both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli are used to investigate the antibacterial activity of the positively charged and uncharged polymer surfaces. The results surprisingly show that the polyaniline surface can inhibit the growth of both bacteria even when chloroxylenol is used below its minimum inhibitory concentration. This study provides new insights allowing the better understanding of dopant-based, intrinsically conducting polymer surfaces for use as antibacterial fiber mats.

Synthesis and Antibacterial Aspects of Graphitic C3N4@Polyaniline Composites

In this work, Pani and Pani@g-C3N4 was synthesized by in situ oxidative polymerization methodology of aniline, in the presence of g-C3N4. The as prepared Pani@g-C3N4 was characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction (XRD). The morphological analysis showed well dispersed Pani in g-C3N4, as well as the coating of Pani on g-C3N4. The XRD further revealed this, and peaks of Pani as well as g-C3N4 was observed, thereby suggesting successful synthesis of the composite. The DC electrical conductivity studies under isothermal and cyclic aging conditions showed high stability of composites over 100 °C. Further, the synthesized composite material proved to be an excellent antimicrobial agent against both type i.e., gram positive Streptococcus pneumoniae and negative bacteria Escherichia coli. In the zone inhibition assay 18 ± 0.5, 16 ± 0.75 and 20 ± 0.5, 22 ± 0.5 mm zone diameter were found against E. coli and S. pneumoniae in presence of pure g-C3N4 and Pani@g-C3N4 at 50 µg concentrations, respectively. Further antimicrobial activity in the presence of sunlight in aqueous medium showed that Pani@g-C3N4 is more potent than pure g-C3N4.

Dual responsive linalool capsules with high loading ratio for excellent antioxidant and antibacterial efficiency

Linalool is a main component in different naturally derived essential oils, and widely used in household, personal care, food and therapeutic formulations. However, the application is limited due to its high volatility and low stability. In this study, an effective encapsulation with high loading ratio was built up together with thermal-redox dual responsiveness and controlled release properties. The emulsified linalool droplets were modified with carbon-carbon double bonds, followed by the precipitation polymerization with thermal sensitive monomer, N-vinyl caprolactam. The average size and the loading ratio of the prepared linalool capsules were 1.4 μm and 50.41 wt%. The linalool capsules exhibited thermal-redox dual responsive properties and the antioxidant-antibacterial performance. Especially, responding to the stimuli mimicking practical circumstance, the synthesized capsules presented excellent bacteria inhibiting effect. This work may open a new path for fragrance and essential oil encapsulation, enlarging them as the green biological antibacterial agents in different applications.

Effect of structural factors on the physicochemical properties of functionalized polyanilines

This review discusses the physical and physicochemical properties of polyaniline (PANI) derivatives. The most important methods for the preparation of functionalized polyanilines are presented. The presence of various substituents in its structure changes the polymer characteristics significantly due to steric and electronic effects of the functional groups. This review describes the relationship between the properties of functionalized polyanilines depending on the nature, number and position of the substituents at the aromatic ring.

Ultrasonic-Assisted Synthesis and Characterization of Chitosan-Graft-Substituted Polyanilines: Promise Bio-Based Nanoparticles for Dye Removal and Bacterial Disinfection

The sonication-mediated oxidative-radical copolymerization using ammonium persulfate in acidic medium provides a new successful avenue to graft Chitosan with three methylaniline derivatives. The synthesized Chitosan-graft-polymethylanilines (CGPMA) were characterized using FTIR, UV-vis diffuse reflectance spectroscopy, XRD, thermogravimetric analysis (TGA), elemental analysis, and transmission electron microscopy (TEM). XRD spectra revealed that CGPMA have a higher crystallinity degree compared to the pristine Chitosan. In addition, a methyl position-dependent crystallinity is noticeable for the grafted copolymers. This could be confirmed from TEM images that reflect structure-affected morphologies of different ordering for the graft spherical nanoparticles. Interestingly, the copolymers prepared under ultrasonic irradiation show a high potency in dye uptake compared to nonsonicated ones. Moreover, an antibacterial preliminary test on the as-prepared materials was accomplished. We have achieved promising results, which encourages us to conduct more studies to process these materials in developing biomedical active composites.

Progress in Conductive Polyaniline-Based Nanocomposites for Biomedical Applications: A Review

Inherently conducting polymers (ICPs) are a specific category of synthetic polymers with distinctive electro-optic properties, which involve conjugated chains with alternating single and double bonds. Polyaniline (PANI), as one of the most well-known ICPs, has outstanding potential applications in biomedicine because of its high electrical conductivity and biocompatibility caused by its hydrophilic nature, low-toxicity, good environmental stability, and nanostructured morphology. Some of the limitations in the use of PANI, such as its low processability and degradability, can be overcome by the preparation of its blends and nanocomposites with various (bio)polymers and nanomaterials, respectively. This review describes the state-of-the-art of biological activities and applications of conductive PANI-based nanocomposites in the biomedical fields, such as antimicrobial therapy, drug delivery, biosensors, nerve regeneration, and tissue engineering. The latest progresses in the biomedical applications of PANI-based nanocomposites are reviewed to provide a background for future research.

Efficient water disinfection using hybrid polyaniline/graphene/carbon nanotube nanocomposites

Pathogens, such as Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), contaminate water resources and are the main causes of diseases, not just waterborne diseases. The present study aims to fabricate hybrid materials composed of polyaniline (PANI), graphene nanosheets (GNs), and carbon nanotubes (CNTs) and utilize the materials for water disinfection. Thus, a new class of hybrid nanocomposites (PANI/GN/CNTs_a-e) was fabricated under ultrasonic conditions following a well-known in situ oxidative polymerization technique in an aqueous acidic solution. A homogeneous mixture of GNs and CNTs (40/60 weight %) prepared at 2, 5, 10, 20 and 30% fixed ratios of GNs/CNTs was utilized in the fabrication of the nanocomposites. The structure of this new hybrid class of materials was confirmed by various characterization techniques that were utilized to corroborate their assembly. Column removal studies with bacteria indicated that the removal percentages of S. aureus and E. coli were 99.5 and 99.2%, respectively, using PANI/GN/CNTs_e. The bacterial count is an indication of bacterial removal after and before adsorption. Additionally, the data indicated clear synergic effects among the nanocomposites. Reuse studies revealed that the same percentage of adsorption was obtained for four cycles, which shows the PANI/GN/CNTs_e nanocomposites can be reused and recycled for a number of cycles with almost the same bacterial adsorption capability.

Poly (lactic-co-glycolic acid)/graphene oxide composites combined with electrical stimulation in wound healing: preparation and characterization

PURPOSE

In this study, we fabricated multifunctional, electrically conductive composites by incorporating graphene oxide (GO) into a poly (lactic-co-glycolic acid) (PLGA) copolymer for wound repair. Furthermore, the resultant composites were coupled with electrical stimulation to further improve the therapeutic effect of wound repair.

METHODS

We evaluated the surface morphology of the composites, as well as their physical properties, cytotoxicity, and antibacterial activity, along with the combined effects of composites and electrical stimulation (ES) in a rat model of wound healing.

RESULTS

Application of the PLGA/GO composites to full-thickness wounds confirmed their advantageous biological properties, as evident from the observed improvements in wound-specific mechanical properties, biocompatibility, and antibacterial activity. Additionally, we found that the combination of composites and ES improved composite-mediated cell survival and accelerated wound healing in vivo by promoting neovascularization and the formation of type I collagen.

CONCLUSION

These results demonstrated that combined treatment with the PLGA/GO composite and ES promoted vascularization and epidermal remodeling and accelerated wound healing in rats, thereby suggesting the efficacy of PLGA/GO+ES for broad applications associated with wound repair.

Characterization of an Antioxidant and Antimicrobial Extract from Cool Climate, White Grape Marc

Valorization of agricultural waste has become increasingly important. Wastes generated by wineries are high in phenolic compounds with antioxidant and antibacterial properties, which contribute to phytotoxicity, making their immediate use for agricultural means limited. Utilizing a water-based extraction method, the phenolic compounds from winery waste were extracted and purified. The resulting extract was characterized for phenolic composition using high-pressure liquid chromatography-ultraviolet/visible and electrochemical detectors (HPLC-UV/Vis, ECD) for monomers, and spectral assessment of the tannins present using attenuated total reflectance- Fourier transform infrared (ATR-FTIR), FT-Raman, and solid-state nuclear magnetic resonance (SSNMR) spectroscopies. The extract’s antioxidant activity was assessed by the scavenging of the 2,2-diphenyl-1–picrylhydrazyl (DPPH) radical and Folin-Ciocalteu total phenolic assay, and was found to be as effective as a commercially obtained grape extract. The extract’s antimicrobial efficacy was tested for minimum bactericidal concentration using Candida albicans, Escherichia coli 25922, and Staphylococcus aureus 6538, which resulted in greater efficacy against gram-positive bacteria as shown over gram-negative bacteria, which can be linked to both monomeric and tannin polyphenols, which have multiple modes of bactericidal action.

Chitosan & Conductive PANI/Chitosan Composite Nanofibers - Evaluation of Antibacterial Properties

Background:

Within the healthcare industry, including the care of chronic wounds, the challenge of antimicrobial resistance continues to grow. As such, there is a need to develop new treatments that can reduce the bioburden in wounds.

Objective:

The present study is focused on the development of polyaniline (PANI) / chitosan (CH) nanofibrous electrospun membranes and evaluates their antibacterial properties.

Methods:

To this end, experimental design was used to determine the electrospinning windows of both pure chitosan and PANI/CH blends of different ratios (1:3, 3:5, 1:1). The effect of key environmental and process parameters (relative humidity and applied voltage) was determined, as well as the effect of the PANI/CH ratio in the blend and the molecular interactions between PANI and chitosan that led to jet stability.

Results:

The nanofibrous mats were evaluated regarding their morphology and antibacterial effect against model gram positive and gram negative bacterial strains, namely B. subtilis and E. coli. High PANI content mats show increased bactericidal activity against both bacterial strains.

Conclusion:

The blend fibre membranes combine the materials’ respective properties, namely electrical conductivity, biocompatibility and antibacterial activity. This study suggests that electrospun PANI/CH membranes are promising candidates for healthcare applications, such as wound dressings.

Synthesis and characterization of polyaniline-drug conjugates as effective antituberculosis agents

Polyaniline (PANI) and its drug composites with some drugs like Neomycin (NM), Trimethoprim (TMP) and Streptomycin (ST) have been prepared by oxidative polymerization of aniline using hydrochloric acid (HA) and ammonium persulfate (APS) as a dopant and as an oxidant, respectively. The structures of PANI and PANI-drug composites were elucidated by FTIR and NMR spectroscopy, which confirmed the presence of benzenoid and quinoid rings in the synthesized compound. Molecular weight and thermal stability were determined by gel permeation chromatography (GPC) and thermogarvimetric analysis, respectively. From the GPC, PDI values of PANI-NM, PANI-TMP and PANI-ST were found to be 1.37, 1.23 and 1.56, respectively. For the study of antibacterial behavior of the synthesized PANI and PANI-drug composites, different micro-organisms, namely, four Gram positive (S. aureus MTCC 96, B. subtilis MTCC 441, S. pyogenes MTCC 442 and S. mutans MTCC 890) and four Gram negative (S. typhi MTCC 98, KL. pneumoniae MTCC 109, E. coli MTCC 443 and P. aeruginosa MTCC 1688) bacteria were selected due to their pharmacological importance. Some of the PANI-drug composites were found to show excellent results as compared to components polyaniline and drugs used for composite formation. Antituberculosis activity of the PANI and its drug composites against Mycobacterium tuberculosisH₃₇RV (acid fast Bacilli) was determined. MIC values for PANI-NM and PANI-TMP were found to be 0.12 and 0.20 µg/mL, respectively. Results suggested that some of the drug composites may be tried as potential candidates for use as an antituberculoid agent to reduce TB transmission.

Synthesis and Reactivities of Triphenyl Acetamide Analogs for Potential Nonlinear Optical Material Uses

We have synthesized aniline based amides (3a–h) via palladium catalyzed Suzuki cross coupling of N-(2,5-dibromophenyl) acetamide with different arylboronic acids in moderate to good yields. A variety of functional groups were well tolerated in reaction conditions. For exploring the possible applications as optoelectronic devices, the nonlinear optical (NLO) properties of all synthesized derivatives (3a–h) were investigated with the help of density functional theory (DFT) methods. The frontier molecular orbitals analysis and reactivity descriptors were investigated for exploring the reactivities.

Direct grafting of tetraaniline via perfluorophenylazide photochemistry to create antifouling, low bio-adhesion surfaces

Conjugated polyaniline has shown anticorrosive, hydrophilic, antibacterial, pH-responsive, and pseudocapacitive properties making it of interest in many fields. However, in situ grafting of polyaniline without harsh chemical treatments is challenging. In this study, we report a simple, fast, and non-destructive surface modification method for grafting tetraaniline (TANI), the smallest conjugated repeat unit of polyaniline, onto several materials via perfluorophenylazide photochemistry. The new materials are characterized by nuclear magnetic resonance (NMR) and electrospray ionization (ESI) mass spectroscopy. TANI is shown to be covalently bonded to important carbon materials including graphite, carbon nanotubes (CNTs), and reduced graphene oxide (rGO), as confirmed by transmission electron microscopy (TEM). Furthermore, large area modifications on polyethylene terephthalate (PET) films through dip-coating or spray-coating demonstrate the potential applicability in biomedical applications where high transparency, patternability, and low bio-adhesion are needed. Another important application is preventing biofouling in membranes for water purification. Here we report the first oligoaniline grafted water filtration membranes by modifying commercially available polyethersulfone (PES) ultrafiltration (UF) membranes. The modified membranes are hydrophilic as demonstrated by captive bubble experiments and exhibit extraordinarily low bovine serum albumin (BSA) and Escherichia coli adhesions. Superior membrane performance in terms of flux, BSA rejection and flux recovery after biofouling are demonstrated using a cross-flow system and dead-end cells, showing excellent fouling resistance produced by the in situ modification.