Antiseptics and disinfectants are extensively used in hospitals and other health care settings for a variety of topical and hard-surface applications A wide variety of active chemical agents (biocides) are found in these products, many of which have been used for hundreds of years, including alcohols, phenols, iodine, and chlorine Most of these active agents demonstrate broad-spectrum antimicrobial activity; however, little is known about the mode of action of these agents in comparison to antibiotics This review considers what is known about the mode of action and spectrum of activity of antiseptics and disinfectants The widespread use of these products has prompted some speculation on the development of microbial resistance, in particular whether antibiotic resistance is induced by antiseptics or disinfectants Known mechanisms of microbial resistance (both intrinsic and acquired) to biocides are reviewed, with emphasis on the clinical implications of these reports

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Antiseptics and Disinfectants: Activity, Action, and Resistance

http://www.mtdna.or.kr/neowiz/board/up_files/files_17/Chitin_Chitosan_polymers_chemistrySolubilityFiberFormation.pdf

Chitin and chitosan polymers: Chemistry, solubility and fiber formation

A review on plants extract mediated synthesis of silver nanoparticles for antimicrobial applications: A green expertise.

The antibacterial effect and mechanism of action of a silver ion solution that was electrically generated were investigated for Staphylococcus aureus and Escherichia coli by analyzing the growth, morphology, and ultrastructure of the bacterial cells following treatment with the silver ion solution. Bacteria were exposed to the silver ion solution for various lengths of time, and the antibacterial effect of the solution was tested using the conventional plate count method and flow cytometric (FC) analysis. Reductions of more than 5 log10 CFU/ml of both S. aureus and E. coli bacteria were confirmed after 90 min of treatment with the silver ion solution. Significant reduction of S. aureus and E. coli cells was also observed by FC analysis; however, the reduction rate determined by FC analysis was less than that determined by the conventional plate count method. These differences may be attributed to the presence of bacteria in an active but nonculturable (ABNC) state after treatment with the silver ion solution. Transmission electron microscopy showed considerable changes in the bacterial cell membranes upon silver ion treatment, which might be the cause or consequence of cell death. In conclusion, the results of the present study suggest that silver ions may cause S. aureus and E. coli bacteria to reach an ABNC state and eventually die.

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Antibacterial Activity and Mechanism of Action of the Silver Ion in Staphylococcus aureus and Escherichia coli

The surface plasmon response of metal nanoparticles is studied for different shapes and physical environments. For polyhedral nanoparticles, the surface plasmon resonances are studied as a function of the number of faces and vertices. The modification of these surface plasmons by different surrounding media and the presence of a substrate or other nanoparticles is also discussed. We found that polyhedral nanoparticles composed with less faces show more surface plasmon resonances, and as the nanoparticle becomes more symmetric, the main surface plasmon resonance is blue-shifted. It is also found that the corners induce more surface plasmons in a wider energy range. In the presence of a substrate, multipolar plasmon resonances are induced, and as the nanoparticle approaches the substrate, such resonances are red-shifted. The interaction among nanoparticles also induces multipolar resonances, but they can be red or blue-shifted depending on the polarization of the external field.

Surface Plasmons on Metal Nanoparticles: The Influence of Shape and Physical Environment

The measurements of dissociation field effect relaxation in aqueous poly-α,L-glutamic acid were carried out. From the feature of pH dependency of relaxation time, the observed relaxation was attributed to the helix-coil transition. The helical growth rate constant was calculated to be (2.9±2)×107 sec−1 from Schwarz’s equation.

HELIX-COIL TRANSITION OF POLY-α,L-GLUTAMIC ACID IN AQUEOUS SOLUTION STUDIED BY THE DISSOCIATION FIELD EFFECT RELAXATION METHOD

A simple preparation of half N-acetylated chitosan highly soluble in water and aqueous organic solvents.

The interactions between silver ion and DNA were studied kinetically by the stopped flow method. The experimental results show that the reaction between silver ion and GC base pair of DNA proceeds by two steps and that between silver ion and AT base pair of DNA with one step.

Kinetic studies of the interaction between silver ion and deoxyribonucleic acid

Kinetic studies of the helix-coil transition in aqueous solutions of poly(alpha-L-glutamic acid) using the electric field pulse method.

The binding isotherm of sodium dodecyl sulfate to amylose was potentiometrically investigated by using amyloses of various degrees of polymerization from 32 to 1100. From the Scatchard plots, the binding was found to be cooperative for the amyloses of DP≥76 and Langmuir type for those of DP≤57. By analogous experiments using a series of sodium alkyl sulfates, it was clarified that (1) eight carbon atoms of surfactant are required for the complexation and (2) more than twelve carbon atoms of surfactant are required for the cooperative binding. Thus, the amylose has an interrupted helical structure in solution and the cooperativity arises from the hydrophobic interaction between the surfactants included partly in the helic of amylose.

Takayuki Sano

Papers

HELIX-COIL TRANSITION OF POLY-α,L-GLUTAMIC ACID IN AQUEOUS SOLUTION STUDIED BY THE DISSOCIATION FIELD EFFECT RELAXATION METHOD

A simple preparation of half N-acetylated chitosan highly soluble in water and aqueous organic solvents.

Kinetic studies of the interaction between silver ion and deoxyribonucleic acid

Kinetic studies of the helix-coil transition in aqueous solutions of poly(alpha-L-glutamic acid) using the electric field pulse method.

Cooperativity in the Binding of Sodium Dodecyl Sulfate to Amylose