Synthesis and Characterisation of Carrageenan/Polyaniline Films and Its Antibacterial Properties

Yang, Wen Qing (2024) Synthesis and Characterisation of Carrageenan/Polyaniline Films and Its Antibacterial Properties. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

The abundant use of synthetic and non-biodegradable wound dressings in the medical field have been a contributing factor to the plastic pollution. To overcome this, researchers had developed wound dressings made up of biodegradable polymers. However, being antibacterial for improved wound healing is one of the features of an ideal modern wound dressing and these polymers lack it. Therefore, in this research study, polyaniline (PANI) was developed as a potential antibacterial agent and incorporated a biopolymer matrix of κ-carrageenan (κ-CGN). PANI samples were polymerised at different temperatures of 0°C and room temperature through chemical oxidative method where hydrochloric acid (HCl) was used as dopant and ammonium persulfate (APS) as oxidising agent. Fourier Transform Infrared Ray (FTIR), Ultraviolet-visible (UV-Vis), electrical conductivity and thermogravimetric analysis (TGA) were done to determine the characteristics of PANI. Ex-situ polymerisation was applied by adding PANI into κ-CGN with glycerol as plasticiser to produce κ-CGN/PANI films. FTIR, electrical conductivity, tensile test (tensile strength (TS); modulus (M); elongation at break (EB)) and TGA analyses were conducted to characterise the films. κ-CGN with small amount of PANI 0℃ (5 wt%) had its conductivity (1.89✕10-3 Scm-1), mechanical properties (TS: 2.47 MPa; M: 17 MPa; EB: 16.17MPa) and thermal stability (final step thermal decomposition: 390.28℃) improved. The antibacterial activity test was conducted on the films against both bacteria which were Gram-positive, S. aureus and Gram-negative, P. aeruginosa by agar disc diffusion method. Among κ-CGN/PANI (0ºC and Troom) films, only κ-CGN/PANI 0℃ 10% films demonstrated good antibacterial activity against S. aureus with the best inhibition percentage of 37.26% for 24 hours. The mechanism of interaction between PANI (cation of N+ from the quinoid) and S. aureus (anionic bacterial membrane) was held by the electrostatic adhesion causing disruption of the bacteria cell. Thus, these films can potentially be applied as wound dressings. An optimisation test was done by testing κ-CGN/PANI 0℃ 10% films against S. aureus with different incubation intervals where the results obtained showed that the antibacterial activity of the tested films can resist bacteria up to 48 hours.