Biodegradable polymers are compatible, permeable and nontoxic, thus they can provide a useful tool for drug delivery or tissue engineering. These polymers can form hydrogels, which are suitable vehicles for different types of materials e.g. drugs, bioactive molecules or cells. In the case of dentistry, photopolymerization is an obvious method to obtain in situ useable devices which can provide a more efficient way of tailoring drug release. A hydrogel system was developed based on poly-gamma-glutamic acid that was modified with methacryloyl groups to achieve this purpose. The resulting new reactive structure was proved by NMR spectroscopy. The swelling ratio of this type of hydrogel has been found remarkable, over 300 % after 24 h, and it can release 5 ng/mm(2) metronidazole. The prepared hydrogels were nontoxic as viability, cytotoxicity tests and cell morphology investigations proved it. These results render this model system an excellent candidate for use as an in situ curing local drug delivery device. The new photoactive system can be utilized in the treatment of periodontal diseases or raising the effectiveness of drugs used only in the minimal effective dose.