Synthesis and antimicrobial activity of polysaccharide alginate derived cationic surfactant-metal(II) complexes

Nature-inspired innovation: Alginic-kojic acid material for sustainable antibacterial and carbon dioxide fixation

The current environmental consciousness of the world's population encourages researchers to work on new materials that are environmentally benign and able to display the appropriate features for the needed application. To develop high-performing, inexpensive eco-materials, scientists have frequently turned to nature, attempting to mimic its processes' excellent performance at a reasonable price. In this regard, we decided to focus on alginic acid (AA), a polysaccharide widely found in brown algae, and kojic acid (KA), a chelating agent fungi produces. This study proposes rapidly synthesizing a sustainable, biocompatible material (AK) based on AA and KA, employing chlorokojic acid (CKA). The material has a dual function: antibacterial activity on both Gram-positive and Gram-negative bacteria, without any cytotoxic action on human cells in vitro, and catalytic ability to convert CO2 into cyclic carbonates at atmospheric pressure, without solvents, with high yields, and without the use of metals. Furthermore, the material's insolubility in organic solvents allows it to be easily separated from the reaction product and reused for other catalytic cycles. Both applications have a key role in the medical and environmental fields, combating the outbreak of infections and providing an innovative methodology to fix the CO2 on specific substrates.

Unveiling the potential of alginate-based nanomaterials in sensing technology and smart delivery applications

Sensors are applied to many fields nowadays because of their high sensitivity, low cost, time-saving, user-friendly, and excellent selectivity. Current biomedical and pharmaceutical science has one focus on developing nanoparticle-based sensors, especially biopolymeric nanoparticles. Alginate is a widely used biopolymer in a variety of applications. The hydrogel-forming characteristic, the chemical structure with hydroxy and carboxylate moieties, biocompatibility, biodegradability, and water solubility of alginate have expanded opportunities in material and biomedical sciences. Recently, research on alginate-based nanoparticles and their applications has begun. These materials are gaining popularity because of their wide usage potential in the biomedical and pharmaceutical fields. Many review papers describe applications of alginate in the drug delivery field. The current study covers the structural and physicochemical properties of alginate-based nanoparticles. The prospective applications of alginate-based nanomaterials in various domains are discussed, including drug delivery and environmental sensing applications for humidity, heavy metals, and hydrogen peroxide. Moreover, biomedical sensing applications of alginate-based nanoparticles regarding various analytes such as glucose, cancer cells, pharmaceutical drugs, and human motion will also be reviewed in this paper. Future research scopes highlight existing challenges and solutions.

Synthesis, Characterization, and Bioactivities of Polysaccharide Metal Complexes: A Review

Natural polysaccharides are critical to a wide range of fields (e.g., medicine, food production, and cosmetics) for their various remarkable physical properties and biological activities. However, the bioactivities of naturally acquired polysaccharides may be unsatisfactory and limit their further applications. It is generally known that the chemical structure exhibited by polysaccharides lays the material basis for their biological activities. Accordingly, possible structural modifications should be conducted on polysaccharides for their enhancement. Recently, polysaccharides complexed with metal ions (e.g., Fe, Zn, Mg, Cr, and Pt) have been reported to be possibly used to improve their bioactivities. Moreover, since the properties exhibited by metal ions are normally conserved, polysaccharides may be endowed with new applications. In this review, the synthesis methods, characterization methods, and bioactivities of polysaccharide metal complexes are summarized specifically. Then, the application prospects and limitations of these complexes are analyzed and discussed.

Continuous and controllable electro-fabrication of antimicrobial copper-alginate dressing for infected wounds treatment

The contamination of chronic wound with bacteria especially methicillin-resistant Staphylococcus aureus (MRSA) is considered as the major factor interferencing normal wound healing. There still remain great challenges in developing safe and effective wound dressings with wide-spectrum antibacterial functions. Alginate hydrogel is a common dressing for wound treatment. Copper is one of the trace elements in human body with inherent antibacterial activity. Traditional methods for preparing a structure-controlled copper-alginate antibacterial matrix are difficult however, due to the fast and uncontrolled gelation between alginate and metal ions. In this work, we report an electrodeposition method for rapid fabrication of copper cross-linked alginate antibacterial films (Cu²⁺-Alg) with controlled structure and copper content, which is relied on an electrical signal controlled release of copper ions from the reaction of insoluble salt Cu₂(OH)₂CO₃ and the generated protons via water electrolysis on anode. The results prove that the physical structure and chemical composition of the electrodeposited Cu²⁺-Alg films can be continuously modulated by the imposed charges during electrodeposition. In vitro tests demonstrate the film has Cu²⁺ content-dependent bactericidal activities. Film's cytocompatibility is well controlled by the imposed charges for Cu²⁺-Alg fabrication. The MRSA infected wound model in vivo also indicates that Cu²⁺-Alg film can effectively eliminate bacterial infection and suppress host inflammatory responses. We believe this study demonstrates a convenient and controllable strategy to fabricate alginate antibacterial dressings with potential applications for infected wound treatment. More broadly, our work reveals electrodeposition is a general and simple platform to design alginate films with versatile functions.

Antimicrobial Activity of Ca-Alginate/Chitosan Nanocomposite Loaded with Camptothecin

The main aim of this study was to prepare antimicrobial nanocomposites consisting of alginate, chitosan, and camptothecin (CPT). CPT-loaded calcium alginate (Ca-Alg₂) and calcium alginate/chitosan (Ca-Alg₂-CH) nanomaterials were synthesized and characterized using infrared (IR) spectroscopy, X-ray diffraction (XRD), UV-Vis spectroscopy, and scanning electron microscopy (SEM). The antimicrobial activity and the genetic effects of Ca-Alg₂/CPT and Ca-Alg₂-CH/CPT nanomaterials on Staphylococcus aureus, Escherichia coli, and Klebsiella pneumonia were studied. The repetitive element polymerase chain reaction analysis technique was used to assess the changes in the bacterial genetic material due to the processing of the nanomaterials. The results showed the presence of a strong chemical interaction between alginate and chitosan, and CPT was loaded successfully in both Ca-Alg₂/CPT and Ca-Alg₂-CH/CPT nanomaterials. Furthermore, the antimicrobial test showed that the Ca-Alg₂/CPT nanocomposite was susceptible to S. aureus, E. coli, and K. pneumonia; on the other hand, Ca-Alg₂-CH/CPT nanocomposite was more susceptible to E. coli and K. pneumonia and was resistant to S. aureus. The results showed that the Ca-Alg₂/CPT nanocomposite was less efficient than Ca-Alg₂-CH/CPT nanocomposite in killing Gram-negative treated bacteria. Moreover, results revealed that the PCR analysis revealed a polymorphic banding pattern. This observation provides an excellent guide to the ability of some polymers to induce point mutations in DNA.

Insights into the Antimicrobial Activity of Hydrated Cobaltmolybdate Doped with Copper

Molybdates are biocidal materials that can be useful in coating surfaces that are susceptible to contamination and the spread of microorganisms. The aim of this work was to investigate the effects of copper doping of hydrated cobalt molybdate, synthesized by the co-precipitation method, on its antibacterial activity and to elucidate the structural and morphological changes caused by the dopant in the material. The synthesized materials were characterized by PXRD, Fourier Transformed Infrared (FTIR), thermogravimetric analysis/differential scanning calorimetry (TG/DSC), and SEM-Energy Dispersive Spectroscopy (SEM-EDS). The antibacterial response of the materials was verified using the Minimum Inhibitory Concentration (MIC) employing the broth microdilution method. The size of the CoMoO₄·1.03H₂O microparticles gradually increased as the percentage of copper increased, decreasing the energy that is needed to promote the transition from the hydrated to the beta phase and changing the color of material. CoMoO₄·1.03H₂O obtained better bactericidal performance against the tested strains of Staphylococcus aureus (gram-positive) than Escherichia coli (gram-negative). However, an interesting point was that the use of copper as a doping agent for hydrated cobalt molybdate caused an increase of MIC value in the presence of E. coli and S. aureus strains. The study demonstrates the need for caution in the use of copper as a doping material in biocidal matrices, such as cobalt molybdate.

Improvement in the Pharmacological Profile of Copper Biological Active Complexes by Their Incorporation into Organic or Inorganic Matrix

Every year, more Cu(II) complexes are proven to be biologically active species, but very few are developed as drugs or entered in clinical trials. This is due to their poor water solubility and lipophilicity, low stability as well as in vivo inactivation. The possibility to improve their pharmacological and/or oral administration profile by incorporation into inorganic or organic matrix was studied. Most of them are either physically encapsulated or conjugated to the matrix via a moiety able to coordinate Cu(II). As a result, a large variety of species were developed as delivery carriers. The organic carriers include liposomes, synthetic or natural polymers or dendrimers, while the inorganic ones are based on carbon nanotubes, hydrotalcite and silica. Some hybrid organic-inorganic materials based on alginate-carbonate, gold-PEG and magnetic mesoporous silica-Schiff base were also developed for this purpose.

Synthesis, Surface and Antimicrobial Activity of New Lactose-Based Surfactants

This work presents a synthesis method for new surfactants based on lactose. The compounds obtained belong to the homologous series of O-β-D-Galactopyranosyl-(1→4)-N-alkyl-(3-sulfopropyl)-D-glucosamine hydrochloride, containing 12 and 14 carbon atoms in the alkyl chain, and they may serve as an example of cationic surfactants. The newly synthesized compounds exhibit good surface properties, low value of CMC (Critical Micelle Concentration) and good wetting properties. These surfactants' ability to produce foam is considerably higher than in the commercial surfactants. Moreover, antibacterial and fungistatic activity was carried out by well diffusion assay against the selected bacteria (Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa), yeasts (Candida albicans) and filamentous fungi (Fusarium graminearum, F. avenaceum, F. oxysporum, F. culmorum, F. equiseti, Alternaria alternata and Botrytis cinerea). It was shown that the resulting quaternary salts significantly inhibit the growth of tested microorganisms. Antibacterial and fungistatic activity of the surfactant compounds varied depending on the species of bacteria or fungi. The results of antimicrobial activity of new lactose derivatives indicate that the compounds exhibit larger or similar antagonistic activity against tested bacteria and fungi than typical cationic surfactant cetylpyridinium chloride.

Hydrophobic study of increasing alkyl chain length of platinum surfactant complexes: synthesis, characterization, micellization, thermodynamics, thermogravimetrics and surface morphology

This paper contains details on the synthesis, characterization, physicochemical properties and surface morphology of five supramolecular metallosurfactants (SMMSs).