Multi-responsive copolymer gated magnetic mesoporous composite and simultaneous controlling of stimuli to maximize release of encased guest molecules

This research is aimed at designing a multi-/dual-responsive copolymer
gated mesoporous composite microcapsule that allows regulated and
efficient release of active molecules. Temperature and pH are the two
important physiological parameters. In this investigation, both these
physiological parameters are simultaneously regulated to achieve high
release of loaded cargo molecules. Here, mesoporous magnetic mFe3O4/mSiO2
core-particles are modified with a copolymer gate via seeded radical
copolymerization of 2-carboxyethyl acrylate (CEA) and
N-isopropylacrylamide (NIPAM). The composite is referred as
mFe3O4/mSiO2/P(NIPAM-CEA-MBA), where N,N'-methylenebisacrylamide
(MBA) is a cross-linker. The composite surface is mesoporous with average
pore diameter of around 3 nm and is highly paramagnetic (43.08 emu g-1).
The copolymer gate showed both temperature- and pH-responsive phase
transitions. Accordingly, the release of encased biomolecule and drugs
utilizing lysozyme (LZ), vancomycin (VC) and clonazepam (CZ) is further
executed through optimized simultaneous control of temperature and pH. The
release efficiency of LZ, VC and CZ reached 98, 91 and 97 % and the
release rate followed the first order kinetics. The synthesized composite
up to 0.5 mg mL-1 is found suitable for therapeutic in-vivo application.
The overall analyses suggest that the composite prepared can be safely
used as microcapsule, a carrier-based release platform, for drug
molecules.