Entrega assistida por força magnética de desagregadores de biofilme em feridas crónicas infetadas

MAGIC address the lack of therapeutic options for CWI, overcoming treatment obstacles related to biofilm formation, while keeping an optimal environment for wound repair. With MAGIC we will develop an innovative magnetic responsive hydrogel aiming at inducing biofilm disassembly via modulation of gene expression. AON will silence the expression of genes involved in suppression of biofilm disassembling agents. Biofilm embedded bacteria reached by AON using magnetic assisted delivery will start to produce biofilm disruptors which will gradually degrade the extracellular matrix. The gradual biofilm dispersion will avoid a fast disruption which can cause spread of the infection. This treatment is intended to be co-administered with a bactericidal agent. AIM1) Development of magnetic-responsive AON/CPP-grafted-mNPs (AON/CPP-mNPs) Superparamagnetic NPs will be produced and optimized to obtain different magnetization strengths. Larger NPs will have a stronger magnetization while smaller NPs will have a weaker magnetization. The magnetic NPs will be coated with a mixture of poly(D,L-lactide-co-glycolide)-poly(ethylene glycol) (PLGA-PEG) and PLGA-PEG-Maleimide and finally the antibiofilm AON and strain-specific CPP will be grafted to mNPs through thiol-maleimide chemistry. Different ratios of AON/CPP will be tested to maximize bacterial uptake and biological effect. As demonstrated in the case of gold nanoparticles, AON maintain their biological effect when grafted to NPs[13]. mNPs will be widely characterized regarding grafting efficiencies, physicochemical properties, biofilm penetration capacity, ability to be internalized by bacteria, antibiofilm properties and biocompatibility. AIM2) Development of a flexible urethane-modified alginate hydrogel A flexible wound dressing designed to provide optimal environment for wound repair while serving as a reservoir/delivery system for AON/CPP-mNPs will be developed. This hydrogel will combine the moisture-uptake capacity of alginate with the mechanical properties of polyurethanes, aiming to obtain a flexible hydrogel that can be applied to irregular areas of the body, namely on limb wounds such as diabetic foot ulcer. AON/CPP-mNPs magnetic-assisted delivery will be achieved optimizing the crosslinking degree of the network, the strength of the magnetic field and the proximity of the magnet to the dressing. AON/CPP-mNPs with different magnetization strengths and different localization in the hydrogel will allow the controlled release at different time-points. The hydrogel will be characterized regarding physico/chemical properties and assessed/optimized in vitro and ex vivo regarding the release of AON/CPP-mNPs. Magnetic-assisted AON/CPP-mNPs delivery at different time-points from the hydrogel will avoid dressing exchange and debridement/disinfection frequency. AIM3) in vivo validation of the therapeutic approach in a mouse biofilm model of wound infection. After in vitro confirmation of efficiency and biocompatibility, the AON/CPP-mNPs hydrogel will be applied to biofilm infected wounds in mice and antibiofilm/antimicrobial treatment will be assisted by a magnet placed opposite to the wound site. The number and frequency of antibiofilm treatments (AON/CPP-mNPs induction delivery from the hydrogel) to achieve complete biofilm/bacteria elimination will be determined. Synergy with bactericidal agents will be tested by oral co-administration of antibiotics.