Objective    To study the inhibitory effect of peptide nucleic acid (PNA) on biofilm formation of Pseudomonas aeruginosa PAO1 in vitro.     Methods   Sequences of antisense oligonucleotide binding closely to the key gene motA for the early biofilm formation of Pseudomonas aeruginosa PAO1 were designed using Mf

old software and dot hybridization. PNA was synthesized according to the sequences of antisense oligonucleotide which was linked to the cell penetrating peptide (CCPs) (KFF)

3

K to form CCPs-PNA. Pseudomonas aeruginosa PAO1 was treated with CCPs

PNA and CCPs-PNA at different concentrations

and the inhibitory effect of PNA on biofilm formation of Pseudomonas aeruginosa PAO1 was quantitatively detected and observed under a microscope.    Results   PNA and CCPs-PNA inhibited the biofilm formation of Pseudomonas aeruginosa PAO1 in a dose-dependent manner. The inhibitory effect of CCPs-PNA was better than that of PNA on biofilm formation of Pseudomonas aeruginosa PAO1. The inhibitory rate of (KFF)

3

K-PNA was 30%

50% and 70%

respectively

for the biofilm formation of Pseudomonas aeruginosa PAO1 at the concentration of 1

5

and 10 μmol/L. The inhibitory rate of PNA was 3% and 10%

respectively

for the biofilm formation of Pseudomonas aeruginosa PAO1 at the concentration of 5 μmol/L and 10 μmol/L. No effect of CCPs at different concentration was observed on the biofilm formation of Pseudomonas aeruginosa PAO1. The motility of Pseudomonas aeruginosa PAO1 was significantly decreased after treated with CCPs-PNA. The PAO1 radial diameter ratio was 3∶5 between (KFF)

3

K-PNA treatment group and control group.    Conclusion   The PNA targeting motA gene can inhibit the biofilm formation of Pseudomonas aeruginosa PAO1 at the initial stage by suppressing its motility and adsorption

which can be greatly increased by (KFF)

3

K

suggesting that the motA gene or its encoded product can be used a good target to prevent biofilm formation of Pseudomonas aeruginosa PAO1.