Pulsed laser deposition of pepsin thin films

Pulsed laser deposition (PLD) of organic and biological thin films has been extensively studied due to its importance in medical applications among others. Our investigations and results on PLD of a digestion catalyzing enzyme, pepsin, are presented. Targets pressed from pepsin powder were ablated with pulses of an ArF excimer laser (λ = 193 nm, FWHM = 30 ns), the applied fluence was varied between 0.24 and 5.1 J/cm2. The pressure in the PLD chamber was 2.7 × 10−3 Pa. The thin layers were deposited onto glass and KBr substrates. Our IR spectroscopic measurements proved that the chemical composition of deposited thin films is similar to that of the target material deposited at 0.5 and 1.3 J/cm2. The protein digesting capacity of the transferred pepsin was tested by adapting a modified “protein cube” method. Dissolution of the ovalbumin sections proved that the deposited layers consisted of catalytically active pepsin.