A photochemical microreactor used to analyze hydrogen peroxide (H2O2) production of T lymphocytes

In this report we describe a new photochemical reactor and its use in the study of ultraviolet-B light (UVB) dependent H2O2 production by T lymphocytes. In the reactor multiple biological samples rotate around a luminescent tube and thus simultaneously absorb a uniform light-flux. The reactor was developed to expand our earlier studies where we showed that UVB activates T lymphocytes so that 10(7) cells produce about 60 nmol H2O2 per minute. H2O2 has increasingly become recognized as a cell signaling molecule regulating immune reactions mediated by T lymphocytes. Our laboratory is researching the potential of such immune regulators as potential future therapeutic agents. To study photochemical H2O2 production in small samples such as suspensions of T lymphocyte cultures or cell extracts, we designed a reactor in which 12 samples (each 50 - 500 microliters) can be exposed to light under temperature-controlled conditions. The samples are mounted on a rotating platform equidistant from the axis of rotation, where the light source of the photoreactor is located. Rotating the samples helps assure that all samples receive a uniform amount of light energy over time. A cooling fan is integrated in the base of the reactor to help minimize convective heat transfer between the lamp and the samples. We simultaneously operate two identical systems to be able to compare data that are obtained from light exposed samples under control and experimental conditions. Data on the influence of therapeutically relevant electromagnetic fields on H2O2 production of T lymphocytes are presented. H2O2 was quantified using the Amplex Red dye.