An antibacterial dimethylamino-chalcone embedded multiblock copolymer (PCL-PEG) was synthesized and characterized using FT-IR, 1H NMR, SEM and SEC and the compound was characterized using FT-IR, 1H NMR, and 13C NMR. A 10% copolymer composite was prepared and casted as film to be used as a biomaterial and the copolymer films without the compound acted as control. TGA, DSC, AFM, SEM and EDAX analysis were performed for the above samples. Surface roughness (Ra) of the copolymer composite film was less when compared to the copolymer film which indicated the proper distribution of chalcone in the composite film. copolymer composite film was hydrophilic compared to copolymer film. Antibacterial adhesion studies were performed for copolymer composite polymer film and evaluated using CFU measurement and SEM analysis. Copolymer composite film shows promising antibacterial adhesion compared to the copolymer film. Hence the copolymer composite film can be used as a new biomaterial endowed with antibacterial properties. © 2011 Elsevier Ltd. All Rights Reserved.

Mukesh Doble

Department Of Biotechnology

Ponnurengan Malliappan Sivakumar

Veluchamy Prabhawathi

ADHESION STUDIES

Antibacterial properties

Bacterial Adhesion

Chalcones

COPOLYMER COMPOSITES

COPOLYMER FILMS

MULTIBLOCK COPOLYMER

SEM ANALYSIS

SEM EDAX

Adhesion

Biological materials

Copolymerization

Copolymers

Plastic products

Polyethylene glycols

Polyethylene oxides

Polymer films

Surface roughness

Composite films

Bacteria (microorganisms)

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Carbohydrate Polymers

Acylated homoserine lactone (AHL)-based quorum sensing (QS) has been reported to be present only in Gram-negative microorganisms. Isolation of a novel Gram-positive microorganism from sea water, capable of producing AHL, is reported here. The isolate (GenBank: JF915892, designated as MPO) belonging to the Exiguobacterium genera is capable of inducing the AHL bioreporters, namely Chromobacterium violaceum CV026, Agrobacterium tumefaceins A136, and E. coli JM 109(psb1075). This inducer is characterized as C3-oxo-octanoyl homoserine lactone (OOHL), and its production reaches a maximum of 15.6 μg L-1, during the stationary growth phase of the organism. MPO extract when exogenously added inhibits the formation of biofilm for the same organism and lowers the extracellular polymeric substances, indicating an AHL-associated phenotypic trait. The isolated sequence of a probable LuxR homolog from MPO (designated as ExgR) shows similar functional domains and contains conserved residues in LuxR from other known bacterial QS LuxR regulators. Also present immediately downstream to ExgR was found a sequence showing homology to known LuxI synthase of Pseudomonas putida. qPCR analysis suggests an increment in exgR mRNA on addition of AHL, further proving the role of ExgR as a QS regulator. © 2013 Federation of European Microbiological Societies.

Fulltext

FEMS Microbiology Letters

Production of acylated homoserine lactone by Gram-positive bacteria isolated from marine water

Nitrated and aminated polycarbonates were prepared chemically, characterized and tested in vitro as a possible biomaterial. Adhesion of Staphylococcus aureus NCIM 5021, Escherichia coli NCIM 2931 and Proteus vulgaris NCIM 2813 and the presence of carbohydrate, protein, CFU and ATP on these surfaces were examined. Cytotoxicity of these surfaces was investigated by growing L929 mouse fibroblast cells. NO2-PC was more hydrophilic than un-PC and reduced adhesion of bacterial protein and carbohydrate. NH2-PC was the most hydrophilic surface biofilm prevention and increased proliferation of the fibroblast cells. The motility of all the three organisms decreased on aminated surface when compared to that on the other two. This study indicated that reducing the surface hydrophobicity alone was not sufficient to develop a biocompatible material, but providing favorable surface functional groups was also a necessary criterion. A strong correlation was observed between the hydrophobicity of the polymer surface and the zeta potential of the organism with bacterial attachment (CFU/ml). A multi-linear regression model with these two parameters was able to fit the observed bacterial attachment data well. © 2013 Elsevier B.V.

Colloids and Surfaces B: Biointerfaces

In vitro biocompatiblity of modified polycarbonate as a biomaterial

Marine paint mixed with 2-methoxy-2',4'-dichloro chalcone is able to considerably reduce the formation of biofilm by Vibrio natriegens, a marine bacterium, on polycarbonate (PC), polymethylmethacrylate (PMMA) and glass fiber reinforced plastic (GFRP). These polymers have been selected for the study, since they have wide marine applications. Surfaces coated with dichloro chalcone containing marine paint had the lowest number of colony forming units (CFU) (1-5×106), proteins (20-30μg/cm2) and carbohydrates (5-10μg/cm2) attached to them after 28 days of exposure to the organism when compared to surfaces coated with CuSO4 mixed paint (20-40×106CFU/ml, proteins of 50-60μg/cm2 and carbohydrates of 40-50μg/cm2) or plain marine paint (30-40×106CFU/ml, proteins of 120-150μg/cm2 and carbohydrates of 40-60μg/cm2). At the end of the study period, the biofilm on PMMA was 7, 10 and 12μm thick on chalcone, copper and plain paint coated surfaces, respectively. The first two paints increased the surface roughness but decreased the surface hydrophobicity when compared to the plain paint. Large number of dead cells was found on the chalcone mixed and predominantly live cells were found on plain paint coated surfaces. 15% of dichloro chalcone had leached out of PMMA surface after 28 days. The low amount of biofilm formed in the presence of dichlorochalcone can be associated to its antibacterial and slimicidal activity and also its ability to reduce the hydrophobicity of the surface. This dichlorochalcone appears to be a novel agent for decreasing the formation of marine biofilm. © 2010 Elsevier B.V.

2-Methoxy-2',4'-dichloro chalcone as an antimicrofoulant against marine bacterial biofilm

Sulfobetaine-modified poly(ethylene terephthalate) (PET) systems were created by physically entrapping the zwitterionic species on the PET surface. The presence of the sulfobetiane molecules on these surfaces were verified by ATR-FTIR and SEM-EDAX analysis, while wettability of the films was investigated by water contact angle measurements. The blood compatibility of the modified films was evaluated by platelet adhesion in human platelet-rich plasma (PRP). The adhesion and inflammatory response of Mouse RAW 264.7 macrophage cells were studied. The surface induced cellular inflammatory response was determined by quantifying the expression levels of proinflammatory cytokines namely TNF-± and IL-1β by measuring their mRNA profiles in the cells using real time polymerase chain reaction normalized to the housekeeping gene GAPDH. L-929 fibroblast cells were used to assess the propensity of the materials to support the fibroblast cell adhesion. A lower platelet adhesion and activation were observed on the sulfobetaine-modified PET film incubated in PRP after 2h when compared to control. The modified film reduced cellular adhesion events ( p<0.05) with respect to the base material, which could be linked to the reduced protein adsorption observed on this surface. The cellular inflammatory response was suppressed on sulfobetaine-modified substrate. Expression levels of pro-inflammmatory cytokines (TNF-± and IL-1β) was found to be upregulated on bare PET, while it was significantly lower on modified PET ( p<0.001). Thus the sulfobetaine entrapment process can be applied on PET in order to achieve low biointeractions and reduced inflammatory host response for various biomedical and biotechnological applications. © 2010 The Author(s).

Journal of Biomaterials Applications

The biocompatibility of sulfobetaine engineered poly (Ethylene Terephthalate) by surface entrapment technique

Antimicrobial property of chalcone coated high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP) and polyurethane (PU) against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa is reported here. The presence of chalcone on the surface was confirmed from fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Bacterial adhesion decreased considerably on all the coated surfaces. Bacterial adhesion was highest on PU surface (most hydrophobic) and lowest on HDPE (most hydrophilic) surface. Chalcone seems to damage the membrane of the bacteria as well as exhibit slimicidal activity. Reasonably good correlation was observed between the CFU (Colony Forming Units) ratio (it is defined as the ratio of CFU on coated surface to the chalcone uncoated surface) at the 24th hour against both hydrophobicity of the microorganism and roughness of the coated polymeric surfaces. Increasing roughness of the polymer and hydrophobicity of the microorganisms were positively and negatively correlated respectively with CFU ratio. Hence, the chalcone coated polymers can be used in the development of newer biomaterials. © 2010 Elsevier B.V. All rights reserved.

Applied Surface Science

3′-Hydroxy-4-methoxychalcone as a potential antibacterial coating on polymeric biomaterials

In this paper, the synthesis of 48 chalcones and their in vitro antifungal activity against Aspergillus flavus NCIM 594, Fusarium proliferatum NCIM1105, Aspergillus niger NCIM 596 and Candida tropicalis NCIM 3556 are reported. Predominantly, the active compounds (6, 9, 14, 27, and 47) against all four fungi have found to have electron withdrawing substitutions in their para substitution in B-ring. Quantitative structure-activity relationship indicated that the antifungal activities are correlated with absorption distribution metabolism and excretion, electrophilicity, spatial and topological descriptors. The statistical measures such as r2 (0.68-0.71), r2-adj (0.62-0.66), q2 (0.60-0.61) and F-ratio (12-17) are reasonable. The data is divided into training and a test set, the former is used to develop the models, and the later is used to test their predictive capability. The predictions are found to be within the 99% confidence level except for two of the cases. SEM (scanning electron microscopy) and BacLight Live/Dead assay indicate that the chalcones act by disrupting the fungal cell wall. © 2009 John Wiley and Sons A/S.

Chemical Biology and Drug Design

Antifungal activity, mechanism and QSAR studies on chalcones

Forty-eight chalcone analogs were synthesized and their in vitro antibacterial activity against Staphylococcus aureus NCIM 5021, Bacillus subtilis NCIM 2718, Phaseolus vulgaris NCIM 2813, Escherichia coli NCIM 2931, Salmonella typhi 2501 and Enterobacter aerogenes NCIM 5139 were evaluated by microdilution broth assay. Quantitative structure-activity relationships were developed for all the cases (r2 = 0.68-0.79; = 0.58-0.78; q 2 = 0.51-0.68; F = 13.02-61.51). Size, polarizability, electron-donating/withdrawing and hydrophilic nature of the molecule determine the activity against these Gram-positive and Gram-negative bacteria. Staphylococcus aureus was the most and S. typhi was the least hydrophobic of these organisms. These chalcones act better against more hydrophobic organisms. The more active chalcones have log P between 1.5 and 3. Compound 24, one of the most active compounds, was found to act by damaging the cell wall of S. aureus. Slimicidal activity of five of the most active compounds (24, 31, 32, 34 and 37) was found to be in the range of 48-60% against S. aureus and 40-54% against E. coli. A correlation was observed among the hydrophobicity of the compounds, hydrophobicity of the bacterial cell surface and the antibacterial activity of the compound. © 2009 Blackwell Munksgaard.

Synthesis, biological evaluation, mechanism of action and quantitative structure-activity relationship studies of chalcones as antibacterial agents

Chalcone embedded polyurethanes as a biomaterial: Synthesis, characterization and antibacterial adhesion

Journal	Carbohydrate Polymers
ISSN	01448617
Open Access	No