TY - JOUR
T1 - Photodynamic Therapy at Low-Light Fluence Rate
T2 - In vitro Assays on Colon Cancer Cells
AU - Rodrigues, J.A.
AU - Amorim, R.
AU - Silva, M.F.
AU - Baltazar, F.
AU - Wolffenbuttel, R.F.
AU - Correia, J.H.
PY - 2019
Y1 - 2019
N2 - This paper presents the results of in vitro photodynamic therapy assays on RKO and HCT-15 cell lines. The envisaged implementation is in autonomous medical microdevices, such as endoscopic capsules for clinical treatment of several types of gastrointestinal tract tumors. Because of their very limited device volume, light fluence and fluence rate needed to destroy tumor cells should be minimized. Foscan or meta-tetra(hydroxyphenyl)chlorin (mTHPC) is used as a photosensitizer. The experimental results show that a small amount of mTHPC (0.15 mg/kg) and light fluence (5-20 J/cm2) is sufficient to obtain significant photodynamic activity. An array of LEDs with peak transmittance at 652 nm is used as a portable light source for the maximum quantum efficiency in producing singlet oxygen. Irradiation to a light fluence between 2.5 and 10 J/cm2 is achieved by an increased exposure time at an 11 mW/cm2 light fluence rate, while mTHPC concentrations of 0.5, 1, 5, and 10 μg/mL are used. The experimental results show that decreased cell viability (down to 30%) can be obtained for 1-5 μg/mL of mTHPC concentrations and 2.5 J/cm2 of light fluence. Such light fluence and light fluence rate are compatible with the endoscopic capsules batteries.
AB - This paper presents the results of in vitro photodynamic therapy assays on RKO and HCT-15 cell lines. The envisaged implementation is in autonomous medical microdevices, such as endoscopic capsules for clinical treatment of several types of gastrointestinal tract tumors. Because of their very limited device volume, light fluence and fluence rate needed to destroy tumor cells should be minimized. Foscan or meta-tetra(hydroxyphenyl)chlorin (mTHPC) is used as a photosensitizer. The experimental results show that a small amount of mTHPC (0.15 mg/kg) and light fluence (5-20 J/cm2) is sufficient to obtain significant photodynamic activity. An array of LEDs with peak transmittance at 652 nm is used as a portable light source for the maximum quantum efficiency in producing singlet oxygen. Irradiation to a light fluence between 2.5 and 10 J/cm2 is achieved by an increased exposure time at an 11 mW/cm2 light fluence rate, while mTHPC concentrations of 0.5, 1, 5, and 10 μg/mL are used. The experimental results show that decreased cell viability (down to 30%) can be obtained for 1-5 μg/mL of mTHPC concentrations and 2.5 J/cm2 of light fluence. Such light fluence and light fluence rate are compatible with the endoscopic capsules batteries.
KW - Biophotonic therapeutic technique
KW - light-tissue interaction
KW - Photodynamic therapy
UR - http://www.scopus.com/inward/record.url?scp=85059044628&partnerID=8YFLogxK
U2 - 10.1109/JSTQE.2018.2889426
DO - 10.1109/JSTQE.2018.2889426
M3 - Article
AN - SCOPUS:85059044628
SN - 0792-1233
VL - 25
SP - 1
EP - 6
JO - IEEE Journal of Selected Topics in Quantum Electronics
JF - IEEE Journal of Selected Topics in Quantum Electronics
IS - 1
M1 - 7202506
ER -
