Mustafa, AbdurrahmanAlsarori, AhmedAkyildiz, HasanKaya, Ismail CihanKaya, Gulcihan Guzel2025-12-242025-12-2420261387-70031879-0259https://doi.org/10.1016/j.inoche.2025.115861Semiconducting nanomaterials have attracted significant attention as antibiotic free antibacterial platforms. However, they suffer from low colloidal stability and photothermal conversion efficiency. In this study, epsilon-poly-Llysine modified FeS2 nanoparticles were synthesized using hot-injection and wet impregnation methods. Photothermal and photodynamic properties for antibacterial phototherapy were investigated under NIR light. The antibacterial efficiency of the nanoparticles was examined in detail against Escherichia coli and Staphylococcus aureus. The structural, morphological, and thermal properties of the samples were characterized using XRD, FT-IR, TGA, and STEM. Photothermal response, thermal stability, and photodynamic properties of the nanoparticles were revealed using heating experiments under light exposure and fluorescent probe measurements, respectively. Photothermal conversion efficiency of the modified nanoparticles was calculated as 65.5%. The in-vitro antibacterial activity was examined via spread plate method, minimum inhibitory and bactericidal concentrations, antibiofilm assay, and live/dead tests. The experiments showed that 30 wt.% epsilon-poly-L-lysine modified FeS2 nanoparticles practically can eliminate both bacteria (Escherichia coli, 99.6% and Staphylococcus aureus, 100%) at 36 degrees C, at a low material concentration of 125 mu g mL-1, and 10 min of light irradiation. These findings indicate an excellent antibacterial activity for FeS2 nanoparticles after a simple surface modification as compared to unmodified FeS2 and show potential in many other chalcogenide-based antibacterial platforms.eninfo:eu-repo/semantics/closedAccessEpsilon-Poly-L-LysinePhotothermalPhotodynamicAntibacterial PhototherapyFeS2Article10.1016/j.inoche.2025.1158612-s2.0-105022591590