Tuneable thermoresponsive hybrid magnetic nanoparticles: preparation, characterization and drug release characteristics

Abstract

BACKGROUND: Thermoresponsive hybrid Ni 0.5 Zn 0.5 Fe 2 O 4 magnetic hydrogel particles based on PEG-g-poly(NIPAM-co-AMPS) were synthesized by soap-free emulsion polymerization of N-isopropylacrylamide (NIPAM) and 2-acrylamido-2-methylpropane sulphonic acid (AMPS) via a free radical mechanism using polyethylene glycol (PEG) as macro-initiator in the presence of N,N'-Methylenebisacrylamide (MBA) as crosslinking agent. The thermoresponsive pure copolymers and hybrid particles were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM) and dynamic light scattering (DLS). Furthermore, the hybrid magnetic particles were used to study the drug release characteristics of theophylline (TPH) as model drug at pH 7.4 and temperature 37 ∘ C. RESULTS:The sizes of the particles were found to be 121 nm to 245 nm at 50 ∘ C and 580 nm to 694 nm at 25 ∘ C depending on the amount of AMPS present in the hybrid particles. The volume phase transition temperature (VPTT) of the hybrid particles was tuned above body temperature from 33 ∘ C to 41 ∘ C. The hybrid magnetic particles with incorporation of AMPS in polymer chains showed high TPH loading capacity compared with that of PEG-g-PNIPAM. The entrapment efficiency of TPH was increasing with increase of AMPS concentration. The releasing capacity of TPH was decreased with increase in AMPS concentration and observed to have sustained drug release profile without initial burst release. CONCLUSIONS: The prepared hybrid particles were both temperature sensitive as well as superparamagnetic, and thus found to be a suitable candidate for applications in targeted drug delivery system. Drug loading capacity and efficiencyThe entrapment efficiency and loading capacity of the TPH for PN0, PN2 and PN4 were calculated using Equation (1) and found to be 88.2%, 89.7% and 92.07% and when calculated using

Hybrid Piezoelectric–Magnetic Self‐Sensing Actuator using Novel Dual‐Alignment Magnetic/Mechanical Processing for Vibration Control of Whole‐Body Vibrations

“…[ 33 ] Despite these disadvantages, magnetic‐stimuli‐responsive property has fast response, easy actuation control, [ 34 ] and can be easily integrated into many polymer‐based matrices, allowing for the fabrication of hybrid and multi‐stimuli‐responsive systems. This includes magnetic/shape–memory actuators, [ 35 ] magnetic hydrogel actuators, [ 36 ] and thermos‐responsive magnetic nanoparticles, [ 37 ] each system utilizing magnetic‐responsive property to enhance the performance of its hybrid system.…”