Chandrasekar S. et al. / International Journal of Biopharmaceutics. 2013; 4(3): International Journal of Biopharmaceutics

Transcription

1 219 e- ISSN Print ISSN International Journal of Biopharmaceutics Journal homepage: IJB HERBAL-CHITOSAN NANOCOMPOSITES FOR DURABLE ANTIBACTERIAL FINISHING ON COTTON MATERIALS 1 Chandrasekar S*, 1 Vijayakumar S, 2 Rajendran R, 3 Rajesh R, 4 Elayarajah B 1 Department of Botany and Microbiology, A.V.V.M. Sri Pushpam College, Tanjore, Tamil Nadu, India. 2 PG and Research Department of Microbiology, PSG College of Arts and Science, Coimbatore, India. 3 Chief Scientist, R&d Bio, The Biosolution Company, Coimbatore, India. 4 School of Biological Sciences, CMS College of Science and Commerce, Coimbatore, India. ABSTRACT To enhance the efficiency of biological, chemical and physical properties of cotton fabrics by finishing with chitosan and herbal extract nanocomposites. Senna auriculata and Achyranthes aspera extracts mixed with chitosan solution was bulk finished directly on 40s cotton fabrics. With an objective to increase efficiency of the functional properties, chitosan and herbal extract nanocomposites were finished on to another set of fabrics (nanocomposite finishing). Various functional properties were analyzed and compared between both the sets of fabrics Antibacterial activity was carried out for both before and after washed samples using standard EN ISO method and a standard AATCC test method respectively. Physical properties like tensile strength, abrasion resistance and air-permeability were also analyzed. Antibacterial activity of nanocomposite finished fabrics showed more inhibitory zones of 30.9 mm for E. coli and 28.9 mm for S. aureus when compared to bulk finished fabrics which had a zone size of 24.9 mm for E. coli and 23.9 mm for S. aureus. Similarly Nanocomposite finished fabrics showed good durable properties and physical properties than bulk finished fabrics. The study concludes that, nanocomposites finish could provide better functional properties to the fabric than the bulk finished material. The nanosized particles in the composites were considered significant for its functional applications in hospital based fabrics to prevent the transmission of nosocomial infections. Key words: chitosan, herbal extract, cotton, nanocomposite. INTRODUCTION Medical industry is challenged by the presence of microorganisms and the negative effects they cause. According to Williams et al., (2005) dramatic effects like deterioration, defacement and odours which occur from the microbial contamination of surfaces as varied as carpeting and medical non-woven fabrics. Purwar and Joshi, (2004) explained that these surfaces can also act as a microbial harbour, as most offer ideal environments Corresponding Author Chandrasekar S sekar_biotech@yahoo.com for the proliferation of microorganisms that are harmful to buildings, textiles and humans. The ability to make surfaces resistant to microbial contamination has advantages in many applications and market segments. Krueger, (2003) also confirmed that this is especially true in medical markets where many products have contributed a degree of aseptic sophistication beyond that required of consumer products. As consumers have become more aware of hygiene and potentially harmful effects of microbes, the demand for antimicrobial finished clothing is increasing (Thilagavathi et al., 2007). In the development of fabrics, functional aspects such as anti-bacterial and UV protection are playing an increased important role

2 220 (Kwong, 2006). Though chemicals and heavy metal finished fabrics provide good antimicrobial activity, due to factors like toxicity, and non-biodegradability, they cannot be used for medical applications. Hence, natural polymers like chitosan and herbal extract finished fabrics were considered significant for medical applications. Chitosan derived from acetylation of chitin, the marine polymer was a best alternative for heavy metals in finishing the medical fabrics. Chitosan is a natural, nontoxic, microbial resistant biodegradable polymer. Its derivatives as antimicrobial agents have received more attention to finish antimicrobial textiles. Similar effects from the extracts of medicinal plants like Senna auriculata and Achyranthes aspera were also considered significant for the functional finishing of textile materials for antibacterial, antifungal and anti odor properties. Even though reactive exhaust method and microencapsulation method have been used extensively in textile industries for functional finishing of fabrics, a novel technique called nanoencapsulation is rapidly emerging and widely used in pharmaceutical, chemical, cosmetics and food processing industries (Wang, 2005).More recent years the method was also expanded to textile finishing industries due to its significant binding properties on cellulosic substrates. Nanoencapsulated drugs after finishing onto the textile materials provides a slow and controlled release of the active antimicrobial ingredient to achieve the desired delay until the right stimulus is obtained (Nataporn Sowasod, 2006). Nanocomposites are formed by the combination of two or more materials that have quite different properties. These different materials work together to give the unique properties of the composite which is the materials individual properties (Rajendran, 2012). Considering the significant characteristics of this technique, in our present research, chitosan and herbal extract nanoparticles were prepared and were functionally finished on the cotton fabrics. To find out the efficiency of nanocomposite finished cotton fabrics, the parameters like antibacterial activity, wash durability and physical properties was compared with chitosan and herbal extracts (bulk) finished cotton fabrics. MATERIALS AND METHODS The entire research work was carried out from February 2012 to June Materials used in the study Fabric material selected for the study was plain weave 40s medical grade cotton with 60 ends per inch (EPI) and 56 picks per inch (PPI). Medicinal plants and chitosan Two medicinal plants, Senna auriculata, Achyranthes aspera and a natural polymer chitosan were collected from Department of Plant Science, Tamil Nadu Agricultural University, Coimbatore, India. Leaves of the plants were used in the study. Test bacterial cultures The test cultures, Escherichia coli and Staphylococcus aureus used in the study were the significant pathogens isolated from the wound dressing fabric materials of a diabetic foot. Preparation of antibacterial agents Methanol extracts of medicinal plants (Thilagavathi and Kannaian, 2008) Fresh leaves of Senna auriculata and Achyranthes aspera was shadow dried at 37 C. Drying was done to reduce the moisture content of leaves to less than 20%. Dried leaves were grounded to make fine powder for the extraction of desired materials. Fine powdered material was extracted to obtain the active substances with suitable solvent (methanol). 10 grams of powdered leaves of Senna auriculata were extracted in 100ml of 80% methanol for 18 hours under shaking condition. For every 6 hours the solution was sonicated for 20 minutes to obtain the exact antibacterial substances of the medicinal plants. Similar procedure was carried out for 10 grams of powdered leaves of Achyranthes aspera Preparation of Chitosan solution (Rajendran et al., 2012) Chitosan (1%) solution was prepared by mixing with acetic acid (1%) and stirred in a magnetic stirrer at 60 C till a fine homogenous suspension was formed. The polymer solution was kept overnight at stand still condition to remove air bubbles formed during stirring. Preparation of antibacterial nanoparticles Herbal extract nanoparticles (Sumithra and Vasugi Raaja, 2012) Herbal extract nanoparticles were prepared by coacervation process by cross-linking with glutaraldehyde for both herbs separately. In this method, the herbal extract was incubated with bovine serum albumin (wall material 2% w/v) for one hour at room temperature. Using 1M HCl ph was adjusted to 5.5. Ethanol was added to the solution in the ratio of 2:1 (v/v) at the rate of 1ml/min. Coacervate thus formed was hardened with 25% glutaraldehyde for 2 hours to allow cross-linking of protein. Organic solvents were removed by rotary vacuum evaporator and resultant nanocapsules were purified by centrifugation at 4 C at 10,000 rpm. Pellets were suspended in 0.1M PBS (ph 7.4) and lyophilized with mannitol (2% w/v). Chitosan nanoparticles (Rajendran et al., 2012) Chitosan nanoparticles were prepared by emulsion method. Briefly, 100ml of 1.5% of

3 221 tripolyphosphate solution was added into chitosan solution (100ml of 2mg/ml in 1% diluted acetic acid) at a rate of 10ml/min under constant stirring condition till a milky emulsion was obtained (ph-5.0). The emulsion was frozen at -4 C followed by thawing in the atmosphere to get solid nanoparticles. The emulsion was centrifuged at 10,000 X for 30 min. Finally, the deposited nanoparticles were washed, vacuum dried at 60 C for 18 hours and stored at 4 C. Bulk and nanocomposite finishing of cotton fabrics Two sets of fabric samples were used in this study. In the first set of samples the prepared antibacterial agents were directly finished (bulk finishing) with herbal extracts of Senna auriculata and Achyranthes aspera and chitosan). In the second set of fabric samples, similar herbal nanoparticles and chitosan nanoparticles (nanocomposite finishing) were finished. All the samples were padded with 8% citric acid in a padding mangle at a pressure of 3 psi with 100% wet pickup followed by drying and curing at 160 C for 5 min. Comparative analysis of bulk and nanocomposite finished cotton fabrics Fabrics finished with antibacterial agents and with antibacterial nanoparticles were compared for different biological and physical properties. Antibacterial assessment of the finished fabric (EN ISO test method) The antibacterial activity of two sets of finished fabric (bulk and nanocomposite) was tested according to EN ISO against the test bacterial cultures, Escherichia coli and Staphylococcus aureus. The finished cotton fabric with the diameter of 20 ± 1 mm was placed on the surface of Nutrient agar medium which was swabbed with the bacterial cultures. The plates were incubated at 37 ºC for 24 hours to measure the zone of inhibition in millimeters formed around the fabric. Wash durability of finished fabric (AATCC 124 test method) Bulk and nanocomposite finished cotton fabrics were analyzed for their wash durability by subjecting the sample to repeated washing and antibacterial testing using the standard AATCC-124 and AATCC 147 test methods (Parallel streak method). All the samples were washed and its antibacterial activity was analyzed after 1 st, 5 th and 10 th wash. Physical properties of finished cotton fabrics Difference in the physical properties of two sets of finished fabrics was analyzed with untreated control cotton samples. Four significant parameters which were considered for comfort properties of cotton fabric were selected for the study. Tensile strength is the measure of the resistance of the fabric tensile load or stress in either warp or weft direction. Abrasion test was determined the ability of a fabric to withstand damage by friction. Air permeability of a fabric is the volume of air measured in cubic cm passed per second through 1 sq. cm for the fabric at a pressure of one cm. head of water. Also the difference in the weight of the finished fabrics was measured to determine the presence of antibacterial agents. Tensile strength, abrasion resistance and airpermeability were analyzed using the standards, ASTM D , AATCC and ASTM D respectively. RESULTS AND DISCUSSION In the present study, bulk finished and nanocomposite finished cotton fabrics were analyzed to determine their efficiency of biological and physical properties. Antibacterial activity and the durable properties of the nanocomposite finished cotton fabrics were analyzed along with physical properties like air permeability and abrasion resistance to determine the regular use of the finished fabric for hospital workers and patients. Antibacterial assessment of the finished fabric by EN ISO Two sets of finished fabric were assessed for their antibacterial activity by EN ISO against test bacterial cultures. The zone of inhibition for the first set of bulk finished fabric was 24.9 mm and 23.9 mm for E. coli and S. aureus respectively (Table-1). Second set of fabric treated with nanocomposites showed more inhibitory zones than the first set of finished fabric against same test bacterial cultures. Nanocomposite finished fabric inhibited the organisms with the zones of 30.9 mm for E. coli and 28.9 mm for S. aureus (Figure-1). The measured zone of inhibition thus indicated that nanocomposites not only prevented the growth under the fabric also it constantly leached out from the material by restricting the growth of organisms to a greater extent than the first set of finished fabric. Wash durability of finished fabrics (AATCC 124 test method) Difference in the durable properties between two sets of finished fabric was analyzed by repeated industrial washings. Durability was tested based on their antibacterial activity using standard Parallel streak method (AATCC 147 test method). First set of bulk finished fabric showed inhibitory zones of 26.3 mm, 25.9 mm and 25.6 mm for E. coli and 27.6 mm, 26.3 mm and 25.6 mm for S. aureus after 1 st, 5 th and 10 th wash respectively (Table-2). Whereas the second set of samples (nanocomposite finished) provided more inhibitory zones than the first set of finished fabric. After 10 th wash, the inhibitory zone of 26.3 mm and 26.9 mm

4 222 was reported for E. coli and S. aureus (Figure-2) whereas comparatively less inhibitory zone was observed for the bulk finished fabric against the test cultures. This showed that the nanocomposite fabric was able to retain the antibacterial activity even after 10 industrial washes, thereby providing long term durability of the nanocomposite finished fabric. Nano-sized particles of chitosan and herbal extracts played a vital role in providing the durability in finished fabrics. Nanosized particles due to their low concentration also considered significant in reducing the colour in finished fabrics. The colour of plant extracts was a widely-met problem in the applications of textile because treated cotton often change to green colour since higher concentration of crude extracts were used for finishing the fabrics. In the present study nanocomposites containing low concentration of antibacterial agents were finished which provided more antibacterial activity with greater durable properties. Durability of fabric treated with nanoparticles was mainly due to their size of nature in which they are present in the cotton fabric. The nanosized particles embedded easily within the cellulose moieties of cotton, so that it remains constant and released at low concentrations which ultimately required for inhibiting the growth of organisms Physical properties of finished cotton fabrics The physical properties of the nanocomposite finished fabric and bulk finished fabric was compared with untreated control cotton fabric in Table-3. The tensile strength of nanocomposite finished cotton fabrics was found to be similar to untreated control cotton fabrics. Due to nanosized particles the nanocomposite finished fabrics does not vary with the tensile property of untreated control cotton fabrics. Whereas tensile strength of bulk finished fabric showed slightly higher tensile strength to the tune of 3.65 % as compared to that of untreated cotton fabrics. This was mainly due to the Fig 1. Antibacterial assessment of the nanocomposite finished fabric larger size and concentration of the particles that was finished in the fabrics. No change in the abrasion resistance was detected for both the finished fabrics when compared to the untreated cotton after 5 hours at rpm. Similarly, no significant difference in the weight between the nanocomposite finished fabric and untreated control cotton fabric was detected. After finishing with either bulk particles or nanocomposites, addition of antibacterial agents on each fabric samples was calculated. The weight of the samples was measured before and after finishing individually with bulk particles and nanocomposites. Bulk finished samples showed more fabric weight than the nanocomposite finished fabric samples. In this regard, the bulk finished samples showed 3.08% and 2.27% more weight than unfinished and nanocomposite finished samples respectively. Whereas, nanocomposite finished samples showed only 0.82% more weight than the unfinished samples. The results indicated that nanocomposite finished fabric may strongly influence the comfort properties of the wearer. Air-permeability which ultimately tested to decide the comfort properties showed interesting phenomenon of differences between bulk and nanocomposite finishes. Bulk finished fabrics showed relatively low air-permeability than the nanocomposite finished fabrics. Air-permeability of bulk finished fabric was 102cm 3 /cm 2 /sec which was 6.27% less than that of untreated control cotton (95.6cm 3 /cm 2 /sec). Whereas the nanocomposite finished fabric was measured as 96.6cm 3 /cm 2 /sec which was only 1.03 % less than the untreated control samples, ensuring more airpermeability and also influencing the comfort property of the fabric. This may be due to the particle size which was considered to be in nano size; that may not block the pores of fabrics. But the pores in bulk finished fabric may get blocked due to the size of chitosan and herbal particles, which in turn leads to low-permeability of air thus decreasing the comfort properties of the fabric. Fig 2. Wash durability of nanocomposite fabric Assessment was made by EN ISO against two test bacterial cultures E. coli and S. aureus Durable properties were determined after antibacterial assessment against E. coli and S. aureus. Assessment was made using AATCC 147 parallel streak method 5 th wash fabric was presented in the figure

5 223 Table 1. Antibacterial assessment of the finished fabric by EN ISO Test Culture Zone of inhibition (mm) Escherichia coli # Staphylococcus aureus # Unfinished fabric 0 0 Chitosan finished Herbal finished fabric Chitosan+herbal (bulk) finished fabric* Nanocomposite finished fabric* * Values in mm was measured including the diameter size of the fabric (20 mm) # Mean values were tabulated after performing three times for each test culture Table 2. Wash durability of finished fabric by AATCC 124 test method Zone of inhibition (mm) after washes (in numbers) Test Culture Escherichia coli # Staphylococcus aureus # 1 st 5 th 10 th 1 st 5 th 10 th Unfinished fabric 25 # 25 # 25 # 25 # 25 # 25 # Chitosan finished fabric Herbal finished fabric Chitosan+herbal finished fabric* Nanocomposite finished fabric* * Values in mm was measured including the diameter size of the fabric (25 mm) # No inhibitory zone was observed (value given is the actual diameter of the fabric) Table 3. Physical properties of finished cotton fabrics Physical properties Bulk finished fabric Nano-composite finished fabric Untreated control cotton Tensile strength 35.6 kgf 34.6 kgf 34.3 kgf Resistance to abrasion No breakdown of the specimen up to rpm for 5 hours No breakdown of the specimen up to rpm for 5 hours No breakdown of the specimen up to rpm for 5 hours Fabric weight Grams/Sq/Metre (GSM) 74.6 gm / m gm / m gm / m 2 Air permeability 102 cm 3 /cm 2 /sec 96.6 cm 3 /cm 2 /sec 95.6 cm 3 /cm 2 /sec All the tests were tested in triplicates, Mean values were tabulated CONCLUSION In the present study, the advantages of functionally finished nanoparticles on the medical cotton were well determined based on the biological, chemical and physical properties. The nano size of chitosan and herbal extracts increases the durability and antibacterial activity of finished fabric to a greater extend. Also, no change in physical properties of nanoparticle finished cotton could also influence its wide applications in the hospitals for the workers and patients in providing suitable comfort properties. As future perspective, the biocompatible nature of herbal finished fabrics shall be tested using any standard animal cell lines or Hen s Egg test-chorio allantoic membrane (HET-CAM) test inorder to determine the regular usage of diseased patients in hospitals without any hypersensitivity reactions. ACKNOWLEDGEMENTS We thank, Department of Botany and Microbiology, A.V.V.M. Sri Pushpam College, Poondi, India for the preparation of Herbal extraction and chitosan polymer solution. RndBio, Biosolution Company at Coimbatore for the preparation of chitosan and herbal extract nanocomposites Department of Microbiology, PSG College of Arts and Science, Coimbatore, India for finishing the fabrics with antibacterial agents using padding mangle. REFERENCES AATCC Test Method 124, Smoothness Appearance of Fabrics after Repeated Home Laundering. American Association of Textile Chemist and Colorist, AATCC technical Manual. 2010; AATCC Test Method 147, Antibacterial Activity Assessment of Textile Materials. American Association of Textile Chemist and Colorist. AATCC technical Manual. 1998;

6 224 EN ISO 20645:2004. Determination of antibacterial activity - Agar diffusion plate test. Technical Committee CEN/TC James WK. Reducing Microbial Contamination in Hospital Blankets. Journal of AEGIS. 2003; 1: 1-11 Kwong T. Durable antibacterial finish on cotton fabric by using chitosan based polymeric core-shell particles. Journal of Applied Polymer Science. 2006; 102(2): Nataporn S, Tawatchai C and Wiwuthanthapanichakoon. Nanoencapsulation of curcumin in biodegradable chitosan via multiple emulsion/solvent evaporation. Thailand Material Science and Technology Conference Purwar R and Joshi M. Recent Developments in Antimicrobial Finishing of Textiles- a Review. AATCC Review. 2004; 4: Rajendran R, Radhai R, Balakumar C, Hasabo A. Mohammad Ahamed, Vigneswaran C and Vaideki K. Synthesis and Characterization of Neem Chitosan Nanocomposites for Development of Antimicrobial Cotton Textiles. Journal of Engineered Fibers and Fabrics. 2012; 7(1): Sumithra M and Vasugi Raaja N. Micro-encapsulation and nano-encapsulation of denim fabrics with herbal extracts. Indian Journal of Fibre and Textile Research. 2012; 37: Thilagavathi G and Kannaian T. Application of Prickly chaff (Achyranthes aspera Linn.) leaves as herbal antimicrobial finish for cotton fabric used in healthcare textiles. Natural Product Radiance. 2008; 7(4): Thilagavathi G, Krishna Bala S and Kannian T. Microencapsulation for herbal extracts for microbial resistance in healthcare textiles. Indian Journal of Fibre and Textile Research. 2007; 32: Wang X. Chitosan-metal complexes as antimicrobial agent: Synthesis, characterization and Structure-activity study. Polymer Bulletin. 2005; 55: Williams JF, Halo Source V and Cho U. Antimicrobial Functions for Synthetic Fibers: Recent Developments. AATCC Review. 2005; 5(4): 17-21