TY - JOUR
T1 - THE EFFECT OF IRRADIANCE ON VIRUS STERILIZATION AND PHOTODYNAMIC DAMAGE IN RED BLOOD CELLS SENSITIZED BY PHTHALOCYANINES
AU - Ben‐Hur, E.
AU - Geacintov, N. E.
AU - Studamire, B.
AU - Kenney, M. E.
AU - Horowitz, B.
PY - 1995/2
Y1 - 1995/2
N2 - Abstract— Phthalocyanines are being studied as photosensitizers for virus sterilization of red blood cells (RBC). During optimization of the reaction conditions, we observed a marked effect of the irradiance on production of RBC damage. Using a broad‐band light source (600–700 nm) between 5 and 80 mW/ cm2, there was an inverse relationship between irradiance and rate of photohemolysis. This effect was observed with aluminum sulfonated phthalocyanine (AlPcSn) and cationic silicon (HOSiPc‐OSi[CH3]2 [CH2]3N+[CH3]3I‐ phthalocyanine (Pc5) photosensitizers. The same effect occurred when the reduction of RBC negative surface charges was used as an endpoint. Under the same treatment conditions, vesicular stomatitis virus inactivation rate was unaffected by changes in the irradiance. Reduction in oxygen availability for the photochemical reaction at high irradiance could explain the effect. However, theoretical estimates suggest that oxygen depletion is minimal under our conditions. In addition, because the rate of photohemolysis at 80 mW/cm2 was not increased when irradiations were carried out under an oxygen atmosphere this seems unlikely. Likewise, formation of singlet oxygen dimoles at high irradiances does not appear to be involved because the effect was unchanged when light exposure was in D2O. While there is no ready explanation for this irradiance effect, it could be used to increase the safety margin of RBC virucidal treatment by employing exposure at high irradiance, thus minimizing the damage to RBC.
AB - Abstract— Phthalocyanines are being studied as photosensitizers for virus sterilization of red blood cells (RBC). During optimization of the reaction conditions, we observed a marked effect of the irradiance on production of RBC damage. Using a broad‐band light source (600–700 nm) between 5 and 80 mW/ cm2, there was an inverse relationship between irradiance and rate of photohemolysis. This effect was observed with aluminum sulfonated phthalocyanine (AlPcSn) and cationic silicon (HOSiPc‐OSi[CH3]2 [CH2]3N+[CH3]3I‐ phthalocyanine (Pc5) photosensitizers. The same effect occurred when the reduction of RBC negative surface charges was used as an endpoint. Under the same treatment conditions, vesicular stomatitis virus inactivation rate was unaffected by changes in the irradiance. Reduction in oxygen availability for the photochemical reaction at high irradiance could explain the effect. However, theoretical estimates suggest that oxygen depletion is minimal under our conditions. In addition, because the rate of photohemolysis at 80 mW/cm2 was not increased when irradiations were carried out under an oxygen atmosphere this seems unlikely. Likewise, formation of singlet oxygen dimoles at high irradiances does not appear to be involved because the effect was unchanged when light exposure was in D2O. While there is no ready explanation for this irradiance effect, it could be used to increase the safety margin of RBC virucidal treatment by employing exposure at high irradiance, thus minimizing the damage to RBC.
UR - http://www.scopus.com/inward/record.url?scp=0029243569&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029243569&partnerID=8YFLogxK
U2 - 10.1111/j.1751-1097.1995.tb03959.x
DO - 10.1111/j.1751-1097.1995.tb03959.x
M3 - Article
C2 - 7899507
AN - SCOPUS:0029243569
SN - 0031-8655
VL - 61
SP - 190
EP - 195
JO - Photochemistry and photobiology
JF - Photochemistry and photobiology
IS - 2
ER -