Destruction and control of Toxoplasma gondii tachyzoites using gold nanosphere/antibody conjugates

The targeting and destruction of Toxoplasma gondii (T.gondii) tachyzoites was studied to be achieved with simple antibody-functionalized gold nanospheres. The nanospheres of approximately 20-nm diameter were conjugated to an antibody specified to T.gondii to produce a gold/antibody conjugate. Microscopic imaging and optical properties indicate the presence of 3000 to 3500 gold nanospheres per tachyzoite. There is no significant photothermal destruction of tachyzoites observed in the absence of Au/anti-T.g. and in this case the number of dead tachyzoites did not increase when the laser dose is increased from 900 to 2100J cm^-3. The results also show that an irradiation of 1800J cm ^-3 caused a cell death rate of 13.5%∓3.6%. The percentage of CHO-K1 cells infected by tachyzoites is inhibited when they are incubated with anti-T.G. alone.