Absorbing film assisted laser induced forward transfer of fungi (Trichoderma conidia)

Abstract
We present an investigation on absorbing film assisted laser induced forward transfer (AFA-LIFT) of fungus (Trichoderma) conidia. A KrF excimer laser beam [λ=248nm,FWHM=30ns (FWHM, full width at half maximum)] was directed through a quartz plate and focused onto its silver coated surface where conidia of the Trichoderma strain were uniformly spread. The laser fluence was varied in the range of 02600mJcm2 and each laser pulse transferred a pixel of target material. The average irradiated area was 8×102mm2 . After the transfer procedure, the yeast extract medium covered glass slide and the transferred conidia patterns were incubated for 20 h and then observed using an optical microscope. The transferred conidia pixels were germinated and the areas of the culture medium surfaces covered by the pixels were evaluated as a function of laser fluence. As the laser fluence was increased from 0 to 355mJcm2 the transferred and germinated pixel area increased from 0 to 0.25mm2 . Further increase in fluence resulted in a drastic decrease down to an approximately constant value of 0.06mm2 . The yield of successful transfer by AFA-LIFT and germination was as much as 75% at 355mJcm2 . The results prove that AFA-LIFT can successfully be applied for the controlled transfer of biological objects.