Controlled Release of Therapeutics from Thermoresponsive Nanogels: A Thermal Magnetic Resonance Feasibility Study

Abstract

Thermal magnetic resonance (ThermalMR) accommodates radio frequency (RF)-induced temperature modulation, thermometry, anatomic and functional imaging, and (nano)molecular probing in an integrated RF applicator. This study examines the feasibility of ThermalMR for the controlled release of a model therapeutics from thermoresponsive nanogels using a 7.0-tesla whole-body MR scanner en route to local drug-delivery-based anticancer treatments. The capacity of ThermalMR is demonstrated in a model system involving the release of fluorescein-labeled bovine serum albumin (BSA-FITC, a model therapeutic) from nanometer-scale polymeric networks. These networks contain thermoresponsive polymers that bestow environmental responsiveness to physiologically relevant changes in temperature. The release profile obtained for the reference data derived from a water bath setup used for temperature stimulation is in accordance with the release kinetics deduced from the ThermalMR setup. In conclusion, ThermalMR adds a thermal intervention dimension to an MRI device and provides an ideal testbed for the study of the temperature-induced release of drugs, magnetic resonance (MR) probes, and other agents from thermoresponsive carriers. Integrating diagnostic imaging, temperature intervention, and temperature response control, ThermalMR is conceptually appealing for the study of the role of temperature in biology and disease and for the pursuit of personalized therapeutic drug delivery approaches for better patient care.

Multifunctional Polymeric Nanogels for Biomedical Applications

“…Smart polymers refer to a modification or functionalization of the polymers with side chains or ligands to adjust the polymer hydrophobicity [ 5 , 6 , 7 ]. Additionally, smart polymers can be designed to display distinct stimuli-responsive behaviors, e.g., thermo-, pH-, and redox-responsiveness [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. These environmentally sensitive features have been extensively investigated because site-specific interactions of the DDS can increase specificity, targeted drug release [ 15 , 16 , 17 , 18 ], and diminish side effects [ 19 , 20 ].…”

Patient-Specific Planning for Thermal Magnetic Resonance of Glioblastoma Multiforme

“…Magnetic nanoparticle heating has also shown promising results as localized adjuvant therapy [ 20 , 21 ]. All of these techniques can help to boost treatment efficacy by enhancing the permeability of the blood–brain–barrier for drugs or nanoparticles used in a combined treatment regime [ 22 , 23 , 24 ], with the most intriguing combination being the use of thermoresponsive carriers releasing the drugs only in the heating target site, allowing for a reduction of systemic side effects [ 25 , 26 ]. For the latter as well as for RF hyperthermia treatments in the brain, control over the RF power deposition in magnitude and spatial distribution is essential [ 27 ].…”

Dually Cross-Linked Core-Shell Structure Nanohydrogel with Redox–Responsive Degradability for Intracellular Delivery

“…Therefore, many stimuli-responsive nanohydrogels have been designed and developed as controlled drug delivery systems. The physical or chemical structure of these intelligent nanohydrogels can effectively respond to environmental stimuli such as temperature [28,35,36], pH [37][38][39], redox potential [40][41][42], ionic strength [43,44] or the combination of these factors [45][46][47][48], to achieve the purpose of targeted and controlled drug release. In particular, redox responsive nanohydrogels have been intensively investigated as potential intracellular delivery systems [49].…”