Bacterial resistance is a major healthcare challenge caused by the misuse of antibiotics, leading to ineffective treatments for infections. In orthopedics and dentistry, biofilm formation on implants exacerbates the issue. A promising solution is quorum quenching, which disrupts bacterial communication, with lactonase enzymes showing potential to prevent biofilm and combat resistance.

In this work, Ti6Al4V alloy disks were polished, cleaned, and chemically treated with acid etching and oxidation to prepare the surface (Ti6Al4V CT). After UV activation (Ti6Al4V CT+UV) and calcium treatment (Ti6Al4V CT+UV+Ca), surfaces were functionalized with ST1 lactonase enzyme solution using a concentration of 1000 µg/mL, creating a Ti6Al4V CT+UV+Ca+ST1 1000 sample.

The modified titanium alloy is biocompatible¹ and serves as an excellent platform for biological functionalization. Once confirmed that the enzyme functionalization was carried out through a zeta potential analysis, real-time quantitative PCR revealed that neither the enzyme nor the functionalized titanium samples exhibit traditional antibacterial properties. However, they effectively reduce gene expression related to quorum sensing and virulence factor production in Pseudomonas aeruginosa. Similar effects were not observed with E. coli and S. aureus.

This study demonstrates the potential of ST1 lactonase-functionalized Ti6Al4V alloys to combat bacterial resistance. These findings highlight the promise of quorum quenching as a strategy for biofilm prevention, particularly in implant applications.

¹Surface modification of Ti–6Al–4V alloy for biomineralization and specific biological response: Part I, inorganic modification. (Ferraris et al., 2011)