PHOTOBLUE · Towards rational design of cancer therapeutic drugs: a first principles study of the photosensitization mechanism of methylene blue (Photoblue)

Cancer is a severe health problem and thus the development of effective cancer drugs is one of the first priorities of the European Research Area. Photodynamic therapy (PDT) is a well-recognized process to treat cancer where cell death is caused by the effect of singlet molecular oxygen acting on molecular constituent parts of the cell. The most common way to generate singlet molecular oxygen requires the interaction between a photoexcited triplet photosensitizer and ground state molecular oxygen and, often, a biological compound. The general aim of Photoblue is to unravel the process of photosensitization in PDT by studying theoretically the photosensitizer methylene blue and its interplay with the environment. Methylene blue is selected because it is small to be studied theoretically and its photosensitization mechanism is unknown. To achieve this aim we propose a combination of state-of the-art quantum chemistry and a multilayer hybrid quantum mechanical/molecular mechanics (QM/MM) molecular dynamics technique that will allow a novel understanding of this light-activated process on the atomic level. The dynamical calculations will be performed in the presence of water, molecular oxygen, and DNA in order to mimic a realistic biological environment. Conducting the proposed research will train the applicant in i) using the most advanced ab initio methods to describe ground and electronic excited states and ii) developing molecular dynamical methods to obtain time-resolved information. The coaction of the host group experience in excited state electronic structure calculations and molecular dynamical simulations together with the applicant’s extensive experience in modeling large systems with MM force fields guarantees the feasibility of this challenging project. The experience gained within Photoblue will provide the applicant with the high qualification and scientific maturity to attain an independent position in academia in any European country in the future.