[Quantum dots in oncological surgery: the future for surgical margin status]. / Quantum dots en chirurgie oncologique : un rôle d'avenir pour le marquage des berges d'exérèse?

Quantum dots (QDs) are semi-conductor nanocrystals that emit fluorescence on excitation with a light source. They have excellent optical properties, including high brightness and resistance to photobleaching. Their spectroscopic properties can be modulated by many factors. Recent progress in developing QDs enable us to control the size, shape and surface functionality of nanoparticles for potential application in cancer imaging. QDs with near-infrared emission could be applied to identify sentinel lymph-node. Conjugation of QDs with biomolecules could be used to target tumors in vivo. This article reviewed recent developments and issues in nanotechnology with a particular focus on applications to the surgery.

[In vitro comparison of the photodynamic activity of meso-tetra (m-hydroxyphenyl) chlorin and hematoporphyrin derivative]. / Comparaison in vitro de l'activité photodynamique de la méso-tétra (m-hydroxyphényl) chlorine et de l'hématoporphyrine dérivée.

Meso-tetra (hydroxyphenyl) chlorin (mTHPC) was evaluated in vitro in HT29 human colon adenocarcinoma cell line and compared with hematoporphyrin derivative (HpD). The incorporation kinetics, evaluated by flow cytometry showed that mTHPC and HpD cellular uptake was related to the incubation time until 12 hours, then a plateau appeared. Cytotoxicity assays were performed using MTT test after photoirradiation at 650 nm for mTHPC and 630 nm for HpD. The photodynamic activity of both photosensitizers was influenced by serum protein of the culture medium and time interval between irradiation and photocytotoxicity test with a maximal activity 24 and 48 hrs after the photoirradiation. In optimized experimental conditions i.e. 2% serum protein- containing culture medium, 24 hr-incubation period, cytotoxicity measured 48 hrs after exposure, 10 J/cm2 light fluence, mTHPC appeared approximately 20-fold more active than HpD with IC50 values of 0.2 micrograms/mL and 4.2 micrograms/mL, respectively.