Thin films of bovine serum albumin (BSA) were prepared by near infrared (1064 nm) pulsed laser deposition (PLD). The films comprised nanodots of 24 +/- 4 nm as primary units at laser fluence below 0.5 J cm(-2). Deposition rate of BSA was determined using a quartz crystal microbalance (QCM). The film preserves primary structure of BSA, as confirmed by a matrix assisted laser desorption ionization time of flight mass spectrometer (MALDI-TOF-MS). When the fluence exceeded 10 J cm(-2), we observed partial decomposition of BSA with simultaneous change in the secondary structure of the BSA from alpha-helix to beta-sheet. Fluence dependence of the BSA structure in the deposited layer was discussed in terms of the ablation mechanisms. (c) 2004 Published by Elsevier B.V.