Controlled release of 1,2-benzisothiazolin-3-one-based anion encapsulated in MgAl layered double hydroxides for antibacterial and antifouling applications

The controlled release of antifouling agents from organic coatings is an effective measure against marine biofouling. In this study, MgAl layered double hydroxides (LDH), a two-dimensional nanoparticle, were intercalated with the 1,2-benzisothiazolin-3-one-based anions (BIT-COO−) via an ion-exchange process for achieving controlled release of BIT-based antibacterial agent. Multifunctional X-ray photoelectron spectroscopy, thermogravimetric analyzer, and transmission electron microscopy confirmed the successful loading of BIT intercalated into LDH interlayers. The antibacterial performance of LDH@BIT-COOH was tested by the zone of inhibition method, the plate colony counting method, the turbidity method, and the biofilm method, and results proved that 0.4 mg/mL LDH@BIT-COOH exhibited complete inactivation of E. coli (6 h) and S. aureus (12h). The release study of the LDH@BIT-COOH proved that the release time prolonged to 4500 min after loading. The 5 wt% LDH@BIT-COOH coating exhibited outstanding antibacterial and antifouling properties by using bio-laser confocal microscope, and without obvious toxicity as observed by L929 cell test using enzyme marker, showing potential applications in marine antifouling.