Analysis of the biomolecular profile by Fourier transform vibrational spectroscopy (FT-IR) in Acinetobacter baumannii after application of photodynamic therapy with curcumin "in vitro "

Acinetobacter baumannii stands out for its antimicrobial resistance and high capacity to cause hospital infections, posing a severe threat to global public health. Thus, there is an urgent need for new therapeutic strategies. This work applied photodynamic therapy (PDT) with curcumin to Acinetobacter baumannii, and bacterial cell viability was assessed. Fourier transform infrared spectroscopy (FT-IR) was used to study changes in biomolecules after PDT application, comparing them with control groups that were only irradiated and only with curcumin photosensitizer. According to the results, there was an increase in the total amount of lipids (~0.3 %), total proteins (~0.6 %), and nuclear material (~8.6 %), with a decrease in carbohydrates (~3.0 %) after the appli- cation of PDT, compared to the control group. In the secondary structure of the proteins, a reduction in α-helix (~3.0 %), disordered structure (~7.0 %), and turns (~5.0 %) was observed, with an increase in β-sheets (~8.8 %). The analysis of biomolecular changes by FT-IR after the application of PDT can contribute to understanding the mechanisms of action of cell death, enabling therapeutic strategies to improve diagnosis and clinical treatment.