Hybrid mesoporous silica nanoparticles with catechol-based coatings as novel controlled delivery carriers and sacrificial templates

NADOR, FABIANA; GUISASOLA, EDUARDO; BAEZA, ALEJANDRO; VALLET-REGÍ, MARÍA; RUIZ-MOLINA, DANIEL

Workshop; HINTBCN Scientific Workshop on Biomedical, Health and Bio-Related applications of Hybrid Materials; 2015

Oxidativeself-polymerization of dopamine onto surfaces, inspired by the adhesiveproperties displayed by mussels, has been introduced in the past to generate arange of polydopamine (PDA) coated surfaces [1]. Though very successful, thisapproach is restricted to the specific case of dopamine which contains apendant amino group. Based on this, our research group has been fully committedto develop an alternative and straightforward one-step polymerization strategybased on the oxidation and subsequent polymerization of catechol moieties inpresence of ammonia solutions for the modification of several nano and bulkstructures [2,3]. Among those, mesoporous silica nanoparticles (MSNs) representa very interesting target to coat; MSNs are found to be excellent drug carrierparticles while exhibiting an excellent biocompatibility [4] where thepremature release of the cargo in physiological medium still hinders furtherapplications. In thiscommunication we report the uniform coating of MSNs upon ammonia triggeredpolymerization of different monomeric and dimeric catechol units. The mainresults from this work are:1.   The premature cargo release ofpreloaded MSNs with drugs (as doxorubicin) was decreased compared with theno-coated MSNs after exposure to physiological media and pHs. 2.   The rich chemistry of catecholbuilding blocks has allowed also for the preparation of responsive coatings todifferent environmental perturbations, such as pH modifications.3.   Some specific coatings have beenshown to self-remove the MSN core (sacrificial template) without the need ofany harsh chemical reagent leading to the formation of stable capsules.Besides, in the case of preloaded MSNs, the cargo remained inside the capsulesafter MSN removal. These findings do not only represent a very simple way toget efficient and smart responsive coatings around MSNs but open new venues forthe preparation of capsules from sacrificial cores through the use of mild conditions.