Biocomposite films as support of methylene blue.

CAVALLO JA, ANGEL VILLEGAS N, ARCE MIRANDA JE, PARAJE MG, STRUMIA MC, GOMEZ CG.

Córdoba

Congreso; 1° Reunión Internacional de Ciencias Farmacéuticas RICIFA.; 2010

Dto. de Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba y el Dto. de Farmacia, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario.

  Introduction The synthesis of biocomposite materials obtained from the combination of a natural and a synthetic polymer is being broadly studied, since this type of material displays interesting properties. Biocomposite material has proved useful in such varied fields as biomedical materials, controlled delivery systems, biological tissues engineering and food packaging (1). The biopolymer chitosan is a polysaccharide chemically composed of linkage b-(1,4)-2-amino-2-deoxi-D-glucose, it shows attractive properties such as biocompatibility, biodegradability and antimicrobial activity, particularly useful in biomedical material and vegetable conservation (2). On the other hand, methylene blue is a thiazidic dye and it was considered leading compound in clinical areas, including therapeutics for malaria, schizophrenia and cancer. Therefore, this work aimed at attaining biocomposite films based on polypropylene and modified with chitosan as support of methylene blue in order to study the dye activity against the development of Staphylococcus aureus and Escherichia coli.   Materials and methods Chitosan (CS) low molecular weight, Aldrich-USA; commercial polypropylene film (PP) was supplied by Converflex S.A-Argentina; acrylic acid (AAc), Merck-Germany; benzophenone (BP), p.a. Mallinckrodt-USA; methylene blue (MB), p.a. Anedra-Argentina. First, the PP film was functionalized with carboxyl groups from AAc photo-graft polymerization at room temperature. Then, CS was immobilized through electrostatic bond to the grafted film with PAAc (PP-g-PAAc), obtaining the biocomposite film (PP-g-PAAc-CS). The MB dye was fixed to modified films using two techniques, where either MB was attached to PP-g-AAc-CS film by diffusion (A) or the dye was mixed with CS and then anchored to PP-g-AAc (B). Finally, the antimicrobial and gas permeation property of the film was study.   Results Biocomposite films (PP-g-AAc-CS) based on PP were generated and utilized as support of MB. Using a photograft polymerization of AAc, the PP films was functionalized with carboxylic groups (PP-g-AAc), which attached CS by electrostatic bond. Immobilized MB confirmed to possess redox activity from its reaction with ascorbic acid (UV-Vis. Spectrometry), yielding the technique B a dye content (0.14 mmol/g) higher than in A (0.12 mmol/g). The antimicrobial property of modified film with MB was studied by the disc plate method, using the bacteria S. aureus and E. coli, where it was found that MB retains its antimicrobial activity after being immobilized (Table 1). In addition, the oxygen permeation study (Table 2) confirmed the film permeability to oxygen.   Conclusions Biomedical materials obtained from the combination of natural and synthetic polymers are being broadly used. Taking advantage of its good mechanical properties, PP is modified by AAc photograft polymerization. MB is immobilized to AAc by electrostatic bond, attaching then a CS layer, which provides biocompatibility properties to the film surface.   Acknowledgments The Authors thank CONICET, FONCyT y SECYT-UNC for their financial support. Cavallo thanks CONICET for the doctoral fellowship awarded.   References (1) Dai N.T., Yeh M.K., Chiang C.H., Chen K.C., Lui T.H., Feng A.C., et al. Human single-donor composite skin substitutes based on collagen and polycaprolactone copolymer. Biochem. Biophys. Res. Co. 2009; 386: 21-25. (2) Ye M., Neetoo H., Chen H. Control of Listeria monocytogenes on ham steaks by antimicrobials incorporated into chitosan-coated plastic films. Food Microbiol. 2008; 25: 260-268.     Table 1: Study of antimicrobial property of films   Square sample (diameter: 1 cm) S. aureaus E. coli ATCCa 20b 8816b O157 2Nb PP I (1 cm)c I I I PP-g-AAc NI NI NI NI PP-g-AAc-CS-MB I (2.5 cm)d I (1.4 cm) I (2.9 cm) I (1.9 cm) PP-g-AAc-(CS/MB) I I (0.7 cm) I I (1.9 cm) a)Reference bacteria, b) clinic bacteria, I) sample inhibits bacterial grown, NI) bacterial growth is not inhibited, c) inhibited region under the sample, d) circular diameter of inhibited zone.     Table 2: Oxygen permeation study of modified films.   Sample P [barrer] PP 0.8105 PP-g-AAc 0.0121 PP-g-AAc-CS 0.0109 Introduction The synthesis of biocomposite materials obtained from the combination of a natural and a synthetic polymer is being broadly studied, since this type of material displays interesting properties. Biocomposite material has proved useful in such varied fields as biomedical materials, controlled delivery systems, biological tissues engineering and food packaging (1). The biopolymer chitosan is a polysaccharide chemically composed of linkage b-(1,4)-2-amino-2-deoxi-D-glucose, it shows attractive properties such as biocompatibility, biodegradability and antimicrobial activity, particularly useful in biomedical material and vegetable conservation (2). On the other hand, methylene blue is a thiazidic dye and it was considered leading compound in clinical areas, including therapeutics for malaria, schizophrenia and cancer. Therefore, this work aimed at attaining biocomposite films based on polypropylene and modified with chitosan as support of methylene blue in order to study the dye activity against the development of Staphylococcus aureus and Escherichia coli.   Materials and methods Chitosan (CS) low molecular weight, Aldrich-USA; commercial polypropylene film (PP) was supplied by Converflex S.A-Argentina; acrylic acid (AAc), Merck-Germany; benzophenone (BP), p.a. Mallinckrodt-USA; methylene blue (MB), p.a. Anedra-Argentina. First, the PP film was functionalized with carboxyl groups from AAc photo-graft polymerization at room temperature. Then, CS was immobilized through electrostatic bond to the grafted film with PAAc (PP-g-PAAc), obtaining the biocomposite film (PP-g-PAAc-CS). The MB dye was fixed to modified films using two techniques, where either MB was attached to PP-g-AAc-CS film by diffusion (A) or the dye was mixed with CS and then anchored to PP-g-AAc (B). Finally, the antimicrobial and gas permeation property of the film was study.   Results Biocomposite films (PP-g-AAc-CS) based on PP were generated and utilized as support of MB. Using a photograft polymerization of AAc, the PP films was functionalized with carboxylic groups (PP-g-AAc), which attached CS by electrostatic bond. Immobilized MB confirmed to possess redox activity from its reaction with ascorbic acid (UV-Vis. Spectrometry), yielding the technique B a dye content (0.14 mmol/g) higher than in A (0.12 mmol/g). The antimicrobial property of modified film with MB was studied by the disc plate method, using the bacteria S. aureus and E. coli, where it was found that MB retains its antimicrobial activity after being immobilized (Table 1). In addition, the oxygen permeation study (Table 2) confirmed the film permeability to oxygen.   Conclusions Biomedical materials obtained from the combination of natural and synthetic polymers are being broadly used. Taking advantage of its good mechanical properties, PP is modified by AAc photograft polymerization. MB is immobilized to AAc by electrostatic bond, attaching then a CS layer, which provides biocompatibility properties to the film surface.   Acknowledgments The Authors thank CONICET, FONCyT y SECYT-UNC for their financial support. Cavallo thanks CONICET for the doctoral fellowship awarded.   References (1) Dai N.T., Yeh M.K., Chiang C.H., Chen K.C., Lui T.H., Feng A.C., et al. Human single-donor composite skin substitutes based on collagen and polycaprolactone copolymer. Biochem. Biophys. Res. Co. 2009; 386: 21-25. (2) Ye M., Neetoo H., Chen H. Control of Listeria monocytogenes on ham steaks by antimicrobials incorporated into chitosan-coated plastic films. Food Microbiol. 2008; 25: 260-268.     Table 1: Study of antimicrobial property of films   Square sample (diameter: 1 cm) S. aureaus E. coli ATCCa 20b 8816b O157 2Nb PP I (1 cm)c I I I PP-g-AAc NI NI NI NI PP-g-AAc-CS-MB I (2.5 cm)d I (1.4 cm) I (2.9 cm) I (1.9 cm) PP-g-AAc-(CS/MB) I I (0.7 cm) I I (1.9 cm)