Evaluation of Antimicrobial and Antibiofilm Activity of Citrus medica Fruit Juice Based Carbon Dots against Pseudomonas aeruginosa .

Pseudomonas aeruginosa ( P. aeruginosa ) is one of the common immortal pathogens that cause intense chronic infections in low-immunity patients, significantly evading the immune system and suppressing the respiratory system. This work reports on the synthesis of prominent members of the carbon family, carbon quantum dots (CQDs), from a natural carbon precursor, Citrus medica ( C. medica ) fruit, and their inhibiting property against P. aeruginosa . CQDs synthesized by the conventional hydrothermal method with an average particle size of 4.5 nm exhibit renowned antimicrobial properties. To enhance the properties of the CQDs, nitrogen was doped using ammonium hydroxide as a nitrogen source, and absorption and fluorescence studies and the elemental composition of CQDs were also reported. CQDs potentially inhibited the growth of bacteria at the lowest concentration level of 1.25% (v/v). Similarly, CQDs moderately inhibited biofilm formation at the concentration level of 0.07% (v/v) for both clinical and control strains of P. aeruginosa . A fluorescence microscopy study revealed that the treated strain shows a moderately reduced biofilm formation when compared to the control strain of P. aeruginosa PAO1.