Guanidine Polymer Research Articles

Correction: Novel biocide multifunctional materials based on mesoporous silicas modified by treatment with guanidine polymers and mercaptopropyltrimethoxysilane: synthesis, characterization, and applications

Correction: Novel biocide multifunctional materials based on mesoporous silicas modified by treatment with guanidine polymers and mercaptopropyltrimethoxysilane: synthesis, characterization, and applications

Safety issues in the use of disinfectants based on polyhexamethyleneguanidine (literature review)

The article presents data of the analysis of scientific literature on the toxicity and danger of polyhexamethylene guanidine (PHMG) and based on it disinfectants, which have been widely used for several decades. The COVID-19 pandemic has contributed to a sharp increase in the use of disinfectants, making it important to study the safety of these substances. The presented materials confirm the effectiveness of PHMG and its compounds against a wide range of bacteria, viruses and fungi. The article discusses the mechanism of the bactericidal action of guanidine polymers, based on the destruction of the bacterial cell wall due to the electrostatic effect of positively charged substance molecules on anionic groups on the cellular wall. Methods for using disinfectants based on PHMG for sanitizing various surfaces and media are shown.
 The results of toxicological studies show that polyhexamethyleneguanidine compounds have low toxicity when taken orally, but pose a great danger to the respiratory system. With chronic exposure, they cause pulmonary fibrosis, a serious lung disease, associated with irreversible destruction of the lung architectonics, pulmonary insufficiency and impaired gas exchange due to excessive accumulation of proteins in the extracellular matrix. The use of disinfectants based on polyhexamethylene guanidine is not recommended for aerosol disinfection of indoor air in the presence of people. The presented data also indicate the need for additional toxicological studies to establish threshold doses of PHMG under inhalation exposure.

Prospects for Application of Guanidine-Containing Organomineral Complexes as Biocidal Functional Additives for Waterborne Polymer Materials

The possibility of using organomineral complexes of polyhexamethylene guanidine hydrochloride as a functional additive for a waterborne paint based on polyvinyl acetate has been investigated. Organomineral complexes containing 20 and 30 wt % guanidine polymer have been obtained, with intercalation of polyguanidine chains into the interlayer space of montmorillonite being observed. It has been revealed that the stability of the polymer film to water is retained when organomineral complexes are introduced into a polyvinyl acetate dispersion, whereas the water resistance of the film sharply decreases when free polyguanidine is added. There was no significant influence of organomineral complexes on the rheological characteristics of the dispersion and its sedimentation stability. Testing of waterborne paints with various additives has shown that introduction of organomineral complexes into the material prevents the coating from fouling by biofilms of gram-positive bacteria Staphylococcus aureus and Rhodococcus erythropolis, with the hardness, water resistance, and water-vapor transmission of the coatings being retained at a satisfactory level.

Dramatic reduction of toxicity of Poly(hexamethylene guanidine) disinfectant by charge neutralization

The current study aimed to investigate the toxicity of positively charged polyhexamethylene guanidine (PHMG) polymer and its complexation with different anionic natural polymers such as k-carrageenan (kCG), chondroitin sulfate (CS), sodium alginate (Alg.Na), polystyrene sulfonate sodium (PSS.Na) and hydrolyzed pectin (HP). The physicochemical properties of the synthesized PHMG and its combination with anionic polyelectrolyte complexes (PECs) namely PHMG:PECs were characterized using zeta potential, XPS, FTIR, and TG analysis. Furthermore, cytotoxic behavior of the PHMG and PHMG:PECs, respectively, were evaluated using human liver cancer cell line (HepG2). The study results revealed that the PHMG alone had slightly higher cytotoxicity to the HepG2 cells than the prepared polyelectrolyte complexes such as PHMG:PECs. The PHMG:PECs showed a significant reduction of cytotoxicity to the HepG2 cells than the pristine PHMG alone. A reduction of PHMG toxicity was observed may be due to the facile formation of complexation between the positively charged PHMG and negatively charged anionic natural polymers such as kCG, CS, Alg. Na, PSS.Na and HP, respectively, via charge balance or neutralization. The experimental results indicate that the suggested method might significantly lower PHMG toxicity while improving biocompatibility.

Anchoring Guanidine Polymer onto Sesbania Gum to Endow Excellent Antibacterial Function

AbstractInfectious diseases caused by pathogenic bacteria invasion have become a serious threat to human life and health. In this study, polyhexamethylguanidine (PHMG) is anchored onto sesbania gum (SG) by an oxidation reaction coupled with the Schiff base reaction to endow antibacterial function. By the assistance of the oxidation reaction using sodium periodate (NaIO4) as an oxidizing agent, the oxidized SG (OSG) forms and contributes to the generation of a platform with active sites for further antibacterial modification with PHMG. Then PHMG as antibacterial ingredient covalently bind on OSG, which helps to achieve SG‐PHMG. After the colony counting method and inhibition zone test, SG‐PHMG shows excellent antibacterial ability against 108 CFU mL−1 of Escherichia coli (E. coli). More interestingly, the grafting of PHMG makes SG more hydrophilic, and allows SG‐PHMG fully contact with bacteria, as a result showing excellent antibacterial activity. It is believed that this strategy has great potential for the antibacterial‐associated applications.

Polyguanidine-modified adsorbent to enhance marine applicability for uranium recovery from seawater

The marine applicability of adsorbents intended for recovering uranium from seawater is crucial. For such applicability, the materials must exhibit anti-biofouling properties, seawater pH adaptability (pH~8), and salt tolerance. Extracting uranium from seawater is a long-term project; hence, biofouling, high salt concentrations, and weak alkaline environments negatively affect the adsorption of uranium and damage the recovered materials. Most studies on the extraction of uranium from seawater focus on increasing the adsorption capacity of the employed adsorbent, while its marine applicability is neglected. In the present study, three types of guanidine polymer (GP)-modified acrylic fibers were prepared to investigate the impact of the introduced structure on the marine applicability of the fibers. After screening, the introduction of polyhexamethylene biguanidine (PHMB) is observed to produce PAO-PHMB-A, characterized by excellent marine applicability. The enhanced properties include high antimicrobial activity (109 CFU/mL, 99.71%), good salt tolerance, and optimal adsorption at a pH of 8. Owing to the synergistic effect of its functional groups, the PAO-PHMB-A material exhibits excellent adsorption performance (525.89 mg/g), as well as high selectivity and durability. More importantly, long-term marine tests revealed that PAO-PHMB-A shows a remarkable uranium adsorption capacity (30 d, 3.19 mg/g) and excellent antibacterial activity. Considering its excellent marine applicability and good adsorption performance, the PAO-PHMB-A material developed in this work could serve as a potential adsorbent for engineering applications associated with uranium recovery from seawater.

Improving the efficiency of water fire extinguishing systems operation by using guanidine polymers

This study has established the possibility of obtaining water extinguishing agents, which can reduce hydraulic resistance (with the Toms effect) by using guanidine derivatives.A cationic polyhexamethylene guanidine hydrochloride surfactant with a molecular weight of 10,000–11,000 u was used for experimental study.It has been shown that the addition of insignificant concentrations (0.03–0.290 %) of polyhexamethylene guanidine hydrochloride, which belongs to class IV of toxicity and is an effective inhibitor of biocorrosion, increases a flow rate of water fire extinguishing agent by 1.20–1.78 times when using the RSK-50 fire barrel.We have established experimentally an increase in the flow rate of a polymer solution from drencher nozzles by 1.86–7.69 % in the concentration range (0.3–1.4 %) along the examined pipeline (1 m and 13 m). An increase in pressure by 2–6 % has been observed compared with the initial values under such conditions.The used polymer has properties of a biologically soft surfactant and meets high environmental requirements of the environmental protection and rational use of natural resources. One can use it to develop formulations for environmentally acceptable water extinguishing agents and their application in firefighting practice.The above allows us to argue that the directed use of salts of polyhexamethylene guanidine hydrochloride is possible to reduce hydraulic losses in water extinguishing systems. One can apply them to improve engineering and technical measures for preventing and responding to emergencies

Spectral determination of novel methacryloyl guanidine compounds in water solutions

For production and application of novel biocidal guanidine polymer compounds techniques for monitoring the toxic monomer and oligomer components in polymer aqueous solutions are required. A direct spectroscopic method is offered for determination of methacryloyl guanidine salts, polymer and copolymer in water solutions at native pH. The impact of unsubstituted guanidine and methacrylate guanidine contaminants is also discussed. The spectroscopic method offered is simple, rapid and effective for monitoring contamination of polymethacryloylguanidines with toxic monomer components during synthesis of polymers and copolymers from different monomer salts, during dialysis and other manufacturing stages of biocidal polymers.

Membrane action of polyhexamethylene guanidine hydrochloride revealed on smooth muscle cells, nerve tissue and rat blood platelets: A biocide driven pore-formation in phospholipid bilayers

A well-known cationic biocide of guanidine polymer family, polyhexamethylene guanidine hydrochloride (PHMG) has been tested against smooth muscle cells isolated from swine myometrium, synaptosomes of rat brain nerve terminals and rat blood platelets for the membrane action. It was established that PHMG blocked the activity of Na+,K+-ATPase of smooth muscle cells plasma membrane by 82.2 ± 0.9% at a concentration of 7 ppm, whilst a dose-dependent depolarization of synaptosomes and platelets became appreciable at 100–500 ppm. Comparative studies by the methods of mass spectrometry (MALDI-TOF and PDMS-TOF), viscosimetry, dynamic light scattering and model phospholipid membranes revealed PHMG oligomers with various number of repeat units (8–16) that formed K+-selective potential-dependent pores in sterol-free phosphatidylethanolamine-containing phospholipid bilayers at a concentration of 1 ppm. Obtained results suggest that besides acidic lipids and membrane proteins phosphatidylethanolamine and cholesterol are the other major factors responsible for the differences between PHMG-induced plasma membrane depolarization of microbial and eukaryotic cells and thus, diverse modes of PHMG membrane action.

Hydrogel-Derived Honeycomb Ni3 S4 /N,P-C as an Efficient Oxygen Evolution Catalyst.

The development of high-efficiency electrocatalysts with low costs for the oxygen evolution reaction (OER) is essential, but remains challenging. Herein, a new synthetic process is proposed to prepare Ni3 S4 particles embedded in N,P-codoped honeycomb porous carbon aerogels (Ni3 S4 /N,P-HPC) through a hydrogel approach. The preparation of Ni3 S4 /N,P-HPC begins with the sol-gel polymerization of tripolyphosphate, chitosan, and guanidine polymer that contains metal-binding sites, allowing for the uniform incorporation of Ni ions into the gel matrix, freeze-drying, and subsequent carbonization under an inert atmosphere. This synthesis resolves difficulties in synthesizing the pure Ni3 S4 phase caused by the instability of Ni3 S4 at high temperature, while affording good control of the porous structure and N,P-doping of carbon aerogels. The synergy between the structural advantages of N,P-carbon aerogels (such as easily accessible active sites, high specific surface area, and excellent electron transport) and the intrinsic electrochemical properties of Ni3 S4 result in the outstanding OER performance of Ni3 S4 /N,P-HPC, with overpotentials as low as 0.37 V at 10 mA cm-2 . The work outlined herein offers a simple and effective method for the development of carbon-based electrocatalysts for renewable energy conversion.

Permanent antimicrobial silicone rubber based on bonding guanidine polymers

Recently, silicone rubber (VMQ) was extensively used in household articles and medical devices. To develop a kind of safe and long‐term antimicrobial VMQ was of great significance. In this work, a kind of vinyl‐contained polyhexamethylene guanidine hydrochloride (VPHMG) was synthesized and used as antimicrobial additive for VMQ. With the increasing of VPHMG addition, the mechanical properties and antimicrobial properties of VMQ‐VPHMG were significantly improved. In particular, the antimicrobial rates against Escherichia coli and Staphylococcus aureus were higher than 99.99% as for 4 wt% of VPHMG addition. Moreover, the surface concentration of VPHMG as well as the antimicrobial rates revealed almost unchanged after being extracted by water and methanol. All the results indicated the vinyl‐contained VPHMG vulcanization and therefore provided the permanent antimicrobial performance for VMQ.

The interaction between the guanidine polymers of disinfectants and cytoplasmic organelles

The interaction between the guanidine polymers of disinfectants and cytoplasmic organelles

Guanidine-Containing Organomineral Complexes as Biocide Additives to Polymeric Composites

Obtaining and using polymeric composite materials with biocide properties is of considerable practical interest both for making construction materials stable against biological corrosion and for improving the sanitary-epidemiological situation. The method suggested for obtaining biocide polymeric composites is based on using new guanine-containing polymers immobilized on montmorillonite as biocide additives. Macromolecular compounds based on guanidine polymers are characterized by high biocide efficiency and low toxicity, and their use as organomineral complexes with montmorillonite can rule out washing-out of the additive from the composite and improve the distribution of the additive in the composite. Methods are suggested for obtaining organomineral complexes in a wide range of compositions. It is shown that composites based on polyethylene and the additives have high biocide efficiency toward micromycetes and gram-positive and gram-negative bacteria.

Interactions of Biocidal Polyhexamethylene Guanidine Hydrochloride and Its Analogs with POPC Model Membranes.

The bacterial membrane-targeted polyhexamethylene guanidine hydrochloride (PHGH) and its novel analog polyoctamethylene guanidine hydrochloride (POGH) had excellent antimicrobial activities against antibiotics-resistant bacteria. However, the biocompatibility aspects of PHGH and POGH on the phospholipid membrane of the eukaryotic cell have not yet been considered. Four chemically synthesized cationic oligoguanidine polymers containing alkyl group with different carbon chain lengths, including PHGH, POGH, and their two analogs, were used to determine their interactions with zwitterionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) phospholipids vesicles mimicking the eukaryotic cell membrane. Characterization was conducted by using bactericidal dynamics, hemolysis testing, calcein dye leakage, and isothermal titration calorimetry. Results showed that the gradually lengthened alkyl carbon chain of four oligoguanidine polymers increased the biocidal activity of the polymer, accompanied with the increased hemolytic activity, calcein dye leakage rate and the increased absolute value of the exothermic effect of polymer-POPC membrane interaction. The thermodynamic curve of the polymer-POPC membrane interaction exhibited a very weak exothermic effect and a poorly unsaturated titration curve, which indicated that four guanidine polymers had weak affinity for zwitterionic POPC vesicles. Generally, PHGH of four guanidine polymers had high biocidal activity and relatively high biocompatibility. This study emphasized that appropriate amphiphilicity balanced by the alkyl chain length, and the positive charge is important factor for the biocompatibility of cationic antimicrobial guanidine polymer. Both PHGH and POGH exhibited destructive power to phospholipid membrane of eukaryotic cell, which should be considered in their industry applications.

In Vitro Assessment of the Toxic Effects of an AKWATON based-disinfectant on Human Tissues

The purpose of this study is to prove the potential safe use of AKWATON as a new antimicrobial product. Many service products are often removed from the market due to their toxic effects on the human body or to their aggressiveness towards the environment. Antimicrobial products such as disinfectants may contain harmful ingredients that can cause disease. Some disinfecting products are corrosive or irritating; others produce strong odors, which in the long run can cause real health problems. AKWATON is a new disinfectant, member of the family of guanidine polymers. Its bactericidal, fungicidal and sporicidal properties have been demonstrated and widely documented. In this study, the toxic effects of AKWATON and of three well known commercial antimicrobial products currently on market, were evaluated and compared on various human tissues including eyes, lung, skin and liver cells. The testing were performed using the TB (Trypan blue) and MTT (3-(4,5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) methods. Cell-cultures and the different tests done, showed that the AKWATON based-disinfectant was much less toxic, killing many fewer cells than the commercial disinfectants. It spared more than 64% of skin cells; 65% of lung cells; 66% of eye cells and 64% of liver cells while some well-known disinfectants currently marketed killed 100% of cells. This study demonstrated that AKWATON can be used as an odorless, colorless, non-corrosive and harmless disinfectant for hospital, agriculture industry, farming, food service and household facilities or as antiseptic.

Silicon microring refractometric sensor for atmospheric CO(2) gas monitoring.

We report a silicon photonic refractometric CO(2) gas sensor operating at room temperature and capable of detecting CO(2) gas at atmospheric concentrations. The sensor uses a novel functional material layer based on a guanidine polymer derivative, which is shown to exhibit reversible refractive index change upon absorption and release of CO(2) gas molecules, and does not require the presence of humidity to operate. By functionalizing a silicon microring resonator with a thin layer of the polymer, we could detect CO(2) gas concentrations in the 0-500ppm range with a sensitivity of 6 × 10(-9) RIU/ppm and a detection limit of 20ppm. The microring transducer provides a potential integrated solution in the development of low-cost and compact CO(2) sensors that can be deployed as part of a sensor network for accurate environmental monitoring of greenhouse gases.

Antibacterial performance of polypropylene nonwoven fabric wound dressing surfaces containing passive and active components

A growing number of wound dressing-related nosocomial infections necessitate the development of novel antibacterial strategies. Herein, polypropylene non-woven fabric (PPNWF) was facilely modified with passive and active antibacterial components, namely photografting polymerization both N-Vinyl-2-pyrrolidone (NVP) and glycidyl methacrylate (GMA) monomers, and the introduction of guanidine polymer through the reaction between active amino groups and epoxy groups. The modified samples were confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), respectively. Water contact angle measurement, antibacterial test, platelet and red blood cell adhesion were used to evaluate the hydrophilicity, antibacterial properties and hemocompatibility of the samples. It was found that the antibacterial properties were obviously enhanced, meanwhile significantly suppressing platelet and red blood cell adhesion after the above modification. This PPNWF samples that possess antifouling and antimicrobial properties, have great potential in wound dressing applications.

Developing of a novel antibacterial agent by functionalization of graphene oxide with guanidine polymer with enhanced antibacterial activity

New materials with excellent antibacterial activity attract numerous research interests. Herein, a facile synthetic method of polyethylene glycol (PEG) and polyhexamethylene guanidine hydrochloride (PHGC) dual-polymer-functionalized graphene oxide (GO) (GO-PEG-PHGC), a novel antibacterial material, was reported. The as-prepared products were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), X-ray pattern (XRD) and elemental analysis. The antibacterial effect on the bacterial strain was investigated by incubating both Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus). The results show that GO-PEG-PHGC has enhanced antibacterial activity when compared to GO, GO-PEG or GO-PHGC alone. The improved antibacterial activity was described to be related to a better dispersion of GO-PEG-PHGC in the presence of PEG. This better dispersion leads to a greater contact between the bacteria membrane and nanomaterials, therefore leading to greater cell damage. Not only Gram-negative bacteria but also Gram-positive bacteria are greatly inhibited by this antibacterial agent. With the powerful antibacterial activity as well as its low cost and facile preparation, the GO-PEG-PHGC as a novel antibacterial agent can find potential application in the areas of healthcare and environmental engineering.

Coating PHGH-Modified Starch on Papers to Induce Antimicrobial Properties

In this work, paper was rendered antimicrobial via applying antimicrobial-modified starch as a coating material onto the paper’s surface. The antimicrobial starch was prepared by covalently bonding guanidine polymers using a coupling reaction. Two different coating layers were applied onto the paper’s surface. The first coating layer contained clay mixed with a latex binder (clay 100 g/latex 20 g). The antimicrobial starches, which possessed different grafting ratios of the antimicrobial agent (30 wt.% and 50 wt.%), were applied as the second coating layer on the paper. The results showed that the coating thickness was approximately constant at 4 μm. In the presence of 0.5 to 1.0 wt.% antimicrobial starch on cellulose fibers, the growth inhibition of bacteria was almost 100%. Additionally, the resulting coated paper exhibited high antimicrobial activities against E. coli. Furthermore, the results showed that the coated papers prevented fungal growth.

Polyacrylate guanidine and polymethacrylate guanidine as novel cationic polymers for effective bilirubin binding

The effect of polycationic polymers of polyacrylate guanidine (PAG) and polymethacrylate guanidine (PMAG) on bilirubin absorbance were studied in phosphate buffer (pH 7.4). It was shown that the change in absorbance spectra of bilirubin in the presence of PAG/PMAG can be associated with the formation of a bilirubin-polymer complex and dissociation of tetramers on bilirubin monomers. Also, the organic-inorganic composite materials based on silica gels and guanidine polymers were synthesized via the sol-gel technique. The incorporated guanidine polymers have a big influence on particle size distribution of silica gel due to their high cross-linking ability. The infrared spectroscopy revealed the presence of guanidine polymers inside solid networks of silica gel. The bilirubin adsorption process onto a guanidine functionalized silica surface was investigated. The Langmuir and Redlich-Peterson isotherm models were tested to explain the adsorption mechanism. The analysis of the adsorption isotherms confirms the possibility of electrostatic interactions of bilirubin molecules with guanidine polymers incorporated inside silica matrix. We conclude that cationic guanidine polymers might be effectively applied for bilirubin removal.