A target plate for enhanced matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) analysis of intact biological entities. The target plate comprises an electrically conductive substrate (1) covered at least partially with immobilised photo-reactive nanoparticles (2), acting as a photosensitizer and an ionization device, which drives efficient electron-transfer and radical reactions causing in-source disruption of the envelope structure of intact biological entities (3) and helps in desorption/ionization of components such as lipids, peptides and proteins from the intact biological entities to the MS analyser.