Photodynamic Antibiofilm and Antibacterial Activity of a New Gel with 5-Aminolevulinic Acid on Infected Titanium Surfaces

Abstract

The use of a new gel containing aminolevulinic acid and red light (ALAD–PDI) was tested in order to counteract bacterial biofilm growth on different titanium implant surfaces. The varying antibacterial efficacy of ALAD–PDI against biofilm growth on several titanium surfaces was also evaluated. A total of 60 titanium discs (30 machined and 30 double-acid etched, DAE) were pre-incubated with saliva and then incubated for 24 h with Streptococcus oralis to form bacterial biofilm. Four different groups were distinguished: two exposed groups (MACHINED and DAE discs), covered with S. oralis biofilm and subjected to ALAD + PDI, and two unexposed groups, with the same surfaces and bacteria, but without the ALAD + PDI (positive controls). Negative controls were non-inoculated discs alone and combined with the gel (ALAD) without the broth cultures. After a further 24 h of anaerobic incubation, all groups were evaluated for colony-forming units (CFUs) and biofilm biomass, imaged via scanning electron microscope, and tested for cell viability via LIVE/DEAD analysis. CFUs and biofilm biomass had significantly higher presence on unexposed samples. ALAD–PDI significantly decreased the number of bacterial CFUs on both exposed surfaces, but without any statistically significant differences among them. Live/dead staining showed the presence of 100% red dead cells on both exposed samples, unlike in unexposed groups. Treatment with ALAD + red light is an effective protocol to counteract the S. oralis biofilm deposited on titanium surfaces with different tomography.

The Effects of 5% 5-Aminolevulinic Acid Gel and Red Light (ALAD-PDT) on Human Fibroblasts and Osteoblasts

“…Previous results of in vitro and in vivo studies concerning the ALAD-PDT protocol applied to treat oral infections by killing microbes [ 10 , 11 , 12 , 15 ] drove us to test the same protocol to investigate whether ALAD-PDT may have some effects on cell populations of the oral cavity such as gingival fibroblasts and oral osteoblasts derived from human biopsies.…”

“…Consequently, the 630 nm light irradiation of cells with an increased accumulation of PpIX promotes a highly selective production of ROS, and decreased levels of mitochondrial membrane potential, which induces cell death by both apoptosis and necrosis without damaging the surrounding healthy cells [ 9 ]. The ability of ALAD-PDT to inactivate both Gram-positive and -negative bacteria has been shown in different in vitro studies [ 10 , 11 , 12 ]. ALAD-PDT is effective for biofilm removal from different titanium surfaces, showing encouraging results against peri-implantitis and chronic wounds [ 11 , 13 ].…”

“…The ability of ALAD-PDT to inactivate both Gram-positive and -negative bacteria has been shown in different in vitro studies [ 10 , 11 , 12 ]. ALAD-PDT is effective for biofilm removal from different titanium surfaces, showing encouraging results against peri-implantitis and chronic wounds [ 11 , 13 ]. Incubation with ALAD followed by 630 nm light irradiation was also shown to be effective against Candida albicans , in vitro [ 14 ].…”

Photodynamic Therapy by Mean of 5-Aminolevulinic Acid for the Management of Periodontitis and Peri-Implantitis: A Retrospective Analysis of 20 Patients

“…The same protocol was tested on implant surfaces and proved effective against Pseudomonas aeruginosa [ 22 ]. In vitro tests also demonstrated a significant reduction of Streptococcus oralis on machined and double-etched implant surfaces [ 23 ].…”

Antimicrobial Combined Action of Graphene Oxide and Light Emitting Diodes for Chronic Wound Management

“…During the experiments, the LED handpiece was mounted perpendicularly to the LCWB sample at a 0.5-mm distance. Irradiation was performed under a laminar flow hood in the dark, under aseptic conditions [20,28,42]. For the tests, 630 nm LED alone and plus ALAD (ALAD-PDT) were used.…”