Photoactivable Multimodal Antimicrobial Nanoconstructs

The search of novel antibacterial treatment modalities designed to face problems of an- tibiotic Multi Drug Resistance (MDR) associated with the alarmingly low turnover of new clinically approved antibiotic drugs is one of the main challenges in biomedicine. In this frame, the achievement of tailored systems able to release therapeutic agents in a controlled fashion is one of the growing area in the burgeoning field of nanomedicine. Light represents the most elegant and non-invasive trigger to deliver bio-active compounds on demand at the target site with superb control of three main factors, site, timing and dosage, determin- ing for the therapeutic outcome. In addition, light triggering is biofriendly, provides fast reaction rates and offers the great benefit of not affecting physiological parameters such as temperature, pH and ionic strength, fundamental requisite for biomedical applications. Recent breakthroughs of nanotechnology offer the opportunity to characterize, manipulate and organize matter at the nanometer scale, controlling the size and shape of the result- ing nanomaterials and greatly improving the biocompatibility and the cellular uptake effi- ciency. This thesis focuses on the design and fabrication of light-activated nanoconstructs for the controlled delivery of unconventional therapeutics such as reactive oxygen and nitrogen species, and heat which, in contrast to conventional drugs, do not suffer MDR problems and display reduced systemic effects. A range of nanosystems able to generate individually, sequentially or simultaneously the above cytotoxic agents is reported and, in some case, their antibacterial activity is also investigated. This dissertation is divided in two sections: the first one regards nanomaterials, while the second focuses on molecular hybrid systems, all preceded by a brief in-troduction.