Photodynamic therapy (PDT) is a therapeutic alternative for treating several pathologies, from microbial infections to cancer. PDT involves applying a photosensitizer (PS) that interacts with light in an appropriate wavelength, absorbing its energy and going from the basal to the excited singlet state. This excited state can experience intersystem crossing to the excited triplet state (3PS*). 3PS* can generate reactive oxygen species that induce injury and trigger cell death. Phthalocyanines (Pcs) are among the most studied PSs, and although they present interesting photophysical and photochemical properties, the main inconvenience is their hydrophobic nature, which limits their intravenous application. Using a transporter for the hydrophobic PSs becomes an exciting strategy with liposomes (LPs) being widely studied carriers composed of phospholipid bilayers. Positively charged carriers or cationic drugs increase interaction with surfaces that exhibit anionic charges, whether bacteria or eukaryotic cells, increasing its delivery and therapeutic efficiency.
Liposomes, as described above, are drug delivery systems composed of lipids. These platforms can be designed using natural lipids obtained from plants in order to minimize environmental impact and to achieve with one of the 12 principles of Green chemistry: use of renewable feedstocks (number 7). Its synthesis can also be aligned with green chemistry, using safer solvents than the traditional ones as principle number 5 established. The work presented in this poster has been developed making every effort possible to apply Green Chemistry principles, from using aqueous solutions when possible to designing carefully every experiment and optimizing then to use less resources and to make the minimum amount of waste possible. It is worthy reminding that photodynamic strategy combined with drug encapsulation aims to provoke a therapeutical effect (death of cancer cells or microbes) using:
- Visible light as a reagent, which is consider as a clean reagent;
- A drug delivery system with a similar composition of human cells to guarantee its biocompatibility and biodegradability,
- The minimum amount of possible drug that causes the desired antitumor or antimicrobial effect. This is closely linked with the previous item, because encapsulating the drug optimizes its arrival to the site of interest reducing its systemic toxicity.