The invention relates to biodegradable PLGA bionanoparticles encapsulating the GSE24-2 peptide with telomerase activity, and to pharmaceutical, cosmetic and biotechnological compositions comprising same. The pharmaceutical compositions are useful for treating diseases presenting a telomerase deficiency, such as dyskeratosis congenita, and diseases presenting ageing characteristics, such as Werner syndrome, Rothmund Thompson syndrome, and other diseases where there is DNA damage such as ataxia telangiectasia. The relation also relates to the method for producing said bionanoparticles by means of a w/o/w double emulsion technique.