Nanotechnological Coating Reduces Bacterial Growth on Vascular Prostheses: An In Vitro Bioluminescence Imaging Study

Background: The growing number of implanted prosthetic material may lead to an increasing number of bacterial infections. Prosthetic infections are associated with high mortality and morbidity. Therefore, we fabricated vascular prostheses with a superhydrophobic coating and investigated their resistance to bacterial colonization using bioluminescence imaging measurements.

Method: Prostheses were coated with silicon dioxide (SiO₂) and thus developed a nano-scale roughness with superhydrophobic characteristics. To analyze these surface characteristics, we performed water contact angle and water roll of angle (titled-drop measurements) analysis. Superhydrophobic coated vascular grafts (Group A; n = 8) and untreated control grafts (Group B; n = 8) were incubated with an Escherichia coli bacteria solution under mechanical stress.

The E. coli strain used was previously transformed with the reporter enzyme luciferase to investigate bacterial growth by bioluminescence imaging (BLI) at different time points.

Results: All coated prostheses showed a water contact angle >140° (mean = 153° ± 5.6) and a mean water roll of angle of 15° ± 4.5, confirming the superhydrophobic properties of the processed grafts. Bioluminescence imaging experiments showed a statistically significant reduction of bacterial colonization for superhydrophobic coated prostheses in comparison to untreated controls at all time points (t = 0 minute: Group A 1.27 × 107 [p/s/cm²/sr] versus Group B 9.05 × 108 [p/s/cm²/sr], p < 0.001; t = 30 minutes: Group A 5.22 × 107 [p/s/cm²/sr] versus Group B 2.09 × 109 [p/s/cm²/sr], p < 0.001). At the final measurement (t = 60 minutes) 97% reduction of photon emission (bacterial growth) was observed with superhydrophobic-coated prostheses compared with uncoated controls.

Conclusion: Bacterial colonization of vascular prostheses can be significantly reduced by a superhydrophobic coating in vitro. To prove the biocompatibility, durability, and the protection against bacterial growth in vivo, further experiments need to be conducted.

Publication History

Article published online:
28 January 2023