SERS Investigation of Cancer Cells Treated with PDT: Quantification of Cell Survival and Follow-up.

In this study Surface Enhanced Raman Spectroscopy (SERS) data recorded from mouse mammary glands cancer cells (4T1 cell line) was used to assess information regarding differences between control, death and viable cells after Photodynamic Therapy (PDT) treatment. The treatment used nanoemulsions (NE/PS) loaded with different chloroaluminumphthalocyanine (ClAlP) photosensitizer (PS) contents (5 and 10 µmol × L-1) and illumination (660 nm wavelength) at 10 J × cm-2 (10 minutes). The SERS data revealed significant molecular alterations in proteins and lipids due to the PDT treatment. Principal Component Analysis (PCA) was applied to analyze the data recorded. Three-dimensional and well reproductive PCA scatter plots were obtained, revealing that two clusters of dead cells were well separated from one another and from control cluster. Overlap between two clusters of viable cells was observed, though well separated from control cluster. Moreover, the data analysis also pointed out necrosis as the main cell death mechanism induced by the PDT, in agreement with the literature. Finally, Raman modes peaking at 608 cm-1 (proteins) and 1231 cm-1 (lipids) can be selected for follow up of survival rate of neoplastic cells after PDT. We envisage that this finding is key to contribute to a quick development of quantitative infrared thermography imaging.

Liposomal photosensitizers: potential platforms for anticancer photodynamic therapy.

Photodynamic therapy is a well-established and clinically approved treatment for several types of cancer. Antineoplastic photodynamic therapy is based on photosensitizers, i.e., drugs that absorb photons translating light energy into a chemical potential that damages tumor tissues. Despite the encouraging clinical results with the approved photosensitizers available today, the prolonged skin phototoxicity, poor selectivity for diseased tissues, hydrophobic nature, and extended retention in the host organism shown by these drugs have stimulated researchers to develop new formulations for photodynamic therapy. In this context, due to their amphiphilic characteristic (compatibility with both hydrophobic and hydrophilic substances), liposomes have proven to be suitable carriers for photosensitizers, improving the photophysical properties of the photosensitizers. Moreover, as nanostructured drug delivery systems, liposomes improve the efficiency and safety of antineoplastic photodynamic therapy, mainly by the classical phenomenon of extended permeation and retention. Therefore, the association of photosensitizers with liposomes has been extensively studied. In this review, both current knowledge and future perspectives on liposomal carriers for antineoplastic photodynamic therapy are critically discussed.

Liposomal photosensitizers: potential platforms for anticancer photodynamic therapy

Photodynamic therapy is a well-established and clinically approved treatment for several types of cancer. Antineoplastic photodynamic therapy is based on photosensitizers, i.e., drugs that absorb photons translating light energy into a chemical potential that damages tumor tissues. Despite the encouraging clinical results with the approved photosensitizers available today, the prolonged skin phototoxicity, poor selectivity for diseased tissues, hydrophobic nature, and extended retention in the host organism shown by these drugs have stimulated researchers to develop new formulations for photodynamic therapy. In this context, due to their amphiphilic characteristic (compatibility with both hydrophobic and hydrophilic substances), liposomes have proven to be suitable carriers for photosensitizers, improving the photophysical properties of the photosensitizers. Moreover, as nanostructured drug delivery systems, liposomes improve the efficiency and safety of antineoplastic photodynamic therapy, mainly by the classical phenomenon of extended permeation and retention. Therefore, the association of photosensitizers with liposomes has been extensively studied. In this review, both current knowledge and future perspectives on liposomal carriers for antineoplastic photodynamic therapy are critically discussed.