Magnetic field activated drug delivery using thermodegradable azo-functionalised PEG-coated core–shell mesoporous silica nanoparticles

Abstract

Core-shell Fe3O4@SiO2 mesoporous silica nanoparticles coated with a new thermodegradable polymer allowed the release of a model drug through heating caused by a high frequency oscillating magnetic field. The thermodegradable polymer was made of poly(ethylene glycol) (PEG) functionalised with azo bonds that break with an elevation of temperature.

Azo-Containing Polymers with Degradation On-Demand Feature

“…The latter were used as radical macroinitiators for the synthesis of well-defined block copolymers, [14][15][16][17][18][19][20][21] the fabrication of crosslinked PMMA microspheres, 22 and for the release of molecules grafted onto nanoparticles in imaging or delivery applications. 23,24 It was also shown that the azo-motif can be used to create mechanoresponsive materials that can be degraded upon ultrasonication in solution. 25 We show here that polyamides and polyurethanes comprising 4,4ʹ -azobis(4-cyanovaleric acid) or 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] residues in the backbone display mechanical characteristics that are virtually identical to those of the azo-free reference materials.…”

Synthesis, Functionalization, and Design of Magnetic Nanoparticles for Theranostic Applications

“…[647] In this case, therapeutic cargos are capable of releasing their payloads due to the presence of organic or inorganic moieties [640] www.advancedsciencenews.com www.advhealthmat.de that are responsive to a certain stimuli. [648] Special gate keepers such as coumarin molecules, [649] azobenzene molecules, [650] thymine, [651] and polymers [652] which are responsive to light source as well as grafting of thermosensitive polymers based on poly-N-isopropylacrylamide (PNIPAM) and its derivatives [652,653] have been exploited for a very precise control release of therapeutics in mesoporous silica coated nanoparticles. In a very recent study, Saint-Cricq et al [652] reported design of thermoresponsive polymeric cap for magnetic core-shell Fe 3 O 4 @ SiO 2 mesoporous nanoparticles by incorporating azo bonds into the backbone of poly(ethylene glycol) (azo-PEG) for a controlled drug release (Figure 40).…”

“…[648] Special gate keepers such as coumarin molecules, [649] azobenzene molecules, [650] thymine, [651] and polymers [652] which are responsive to light source as well as grafting of thermosensitive polymers based on poly-N-isopropylacrylamide (PNIPAM) and its derivatives [652,653] have been exploited for a very precise control release of therapeutics in mesoporous silica coated nanoparticles. In a very recent study, Saint-Cricq et al [652] reported design of thermoresponsive polymeric cap for magnetic core-shell Fe 3 O 4 @ SiO 2 mesoporous nanoparticles by incorporating azo bonds into the backbone of poly(ethylene glycol) (azo-PEG) for a controlled drug release (Figure 40). Since azo-PEG responds to temperature, the drug release was triggered by applying an external magnetic field to produce heat locally with a nonscopic volume.…”

“…[660b] These obstacles in the way of performing external magnetic fields for MDT limit its application to superficial tumors and locations in the body that are very near to the surface of the skin wherein both strong magnetic field and field gradients as well as very low-velocity fields of blood flow are present. An alternative strategy to circumvent the limitations of traditional MDT is introduced to literature based on high gradient [652] www.advancedsciencenews.com www.advhealthmat.de magnetic separation (HGMS) concept. [676] Based on this concept, a wide range of theoretical, [677] experimental in vitro [678] and ex vivo [679] studies have shown that a relatively external magnetic field applied on a ferromagnetic material is capable to create a strong localized magnetic field deep within the body.…”

Hierarchical mesoporous silica nanoparticles for tailorable drug release

“…Therefore, improving the drug release controllability of MSNs carriers is the key factor to extend their potential usage to the specific needs for various pathological models. To this end, quite a few stimuli-responsive polymers or bio-macromolecules have been applied to modify the simplex MSNs to further endow them with controllable cargo release profiles (Aznar et al, 2013;Chen et al, 2016;Choi et al, 2014;Kim et al, 2014;Niu et al, 2014;Saint-Cricq et al, 2015). On the other hand, it is well known that the functional properties of MSNs usually depend on their structure features, such as different features of pore including size, shape, hydrophilicity/hydrophobicity, and surface charge, some of which have shown controllable drug release capability (Doane and Burda, 2013;Gao et al, 2011;Li et al, 2011;Natarajan and Selvaraj, 2014;Niu et al, 2014;Slowing et al, 2008;Wang et al, 2013;Zhu et al, 2010).…”