Remote actuation of hydrogel nanocomposites: Heating analysis, modeling, and simulations

Abstract

Recently, there has been increasing interest in remote heating of polymer nanocomposites for applications such as actuators, microfluidic valves, drug delivery devices, and hyperthermia treatment of cancer. In this study, magnetic hydrogel nanocomposites of poly(ethylene glycol) (PEG) with varying amounts of iron oxide nanoparticle loadings were synthesized. The nanocomposites were remotely heated using an alternating magnetic field (AMF) at three different AMF amplitudes, and the resultant temperatures were recorded. The rate of the temperature rise and the steady state temperatures were analyzed with a heat transfer model, and a correlation of heat generation per unit mass with the nanoparticle loadings was established for different AMF amplitudes. The temperature rise data of a PEG system with different swelling properties were found to be accurately predicted by the model. Furthermore, the correlations were used to simulate the temperatures of the nanocomposite and the surrounding tissue for potential hyperthermia cancer treatment applications. V V C 2010 American Institute of Chemical Engineers AIChE J, 57: 852-860, 2011 Keywords: biomaterials, biomedical engineering, nanotechnology, heat transfer, composite materials IntroductionNanoparticulates, such as iron oxide nanoparticles, gold nanorods and nanoshells, and carbon nanotubes (CNT) can be remotely heated with the application of specific external stimuli, such as radiofrequency fields or near-infrared light. 1 The incorporation of these nanoparticulates into a polymer matrix can result in several interesting properties including improved mechanical, thermal, or electrical behavior, 2 as well as the capability of remote actuation. 3,4 In the last few years, there have been several studies on the remote heating of polymer nanocomposites for a variety of applications, such as actuators, 5-8 microfluidic valves, 9,10 drug delivery devices, [11][12][13][14][15] and for hyperthermia cancer treatment. [16][17][18][19] For example, an alternating magnetic field (AMF) has been shown to selectively induce heating and shape transition in magnetic shape memory polymer nanocomposites. 5,8 In another study, Hawkins et al. demonstrated that addition of iron oxide nanoparticles to a degradable hydrogel matrix can allow heating upon AMF exposure, which was in turn used to manipulate the rates of degradation and drug release.14 AMF heating has also been explored to trigger the collapse of magnetic nanocomposites of N-isopropylacrylamide (NIPAAm), a temperature responsive hydrogel. This phenomenon has been used to demonstrate accelerated drug release, as well as microfluidic valve applications. 10,11,15 In a recent study, Meenach et al. observed favorable cell viability of magnetic NIPAAm nanocomposites with NIH 3T3 murine fibroblasts and also showed heating on the application of Correspondence concerning this article should be addressed to J. Z. Hilt at hilt@ engr.uky.edu. AMF.18 In all these studies, heating of the nanocomposites was a key factor, and precise control...

Formulation and characterization of inhalable magnetic nanocomposite microparticles (MnMs) for targeted pulmonary delivery via spray drying

“…Additionally, it has shown promise in treating cancer by enhancing chemotherapy and radiotherapy [27–29]. Locally targeted hyperthermia in the treatment of cancer has the advantage of reducing undesired cellular death to healthy tissue and can be accomplished with MNPs under AMF exposure [8, 30–32]. Previous clinical trials have utilized magnetic nanoparticles under AMF exposure to demonstrate the feasibility of remotely administering interstitial heating to cancer patients [33, 34].…”

Magnetic Nanocomposite Sol–Gel Systems for Remote Controlled Drug Release

“…Secondly, the AMF dosing and subsequent heating will be short compared to the duration of the depot, and thus the surrounding cells may be able to recover from any transient hyperthermia effects. Finally, the temperature profiles inside the nanocomposite gel and in the surrounding tissues can be simulated to allow for appropriate selection of dosing parameters as done in prior studies34.…”

Implementation and modeling of in situ magnetic hyperthermia

“…Magnetite composites of poly(vinyl alcohol) (PVA), poly(ethylene glycol), poly(N-isopropylacrylamide), and poly(acrylamide) have all been reported to wirelessly heat in an AMF, though they are too soft in aqueous environments to be appropriate for orthopedic devices which comprise the largest share of the medical implant market. 1,[43][44][45][46] Moreover, these composite materials were not prepared with large enough iron loadings to meet the power demands described above, nor were they tested with any rigor for determining how the composite will heat differently for different iron loadings as will be shown in Chapter 2 for magnetic composites made with PVA and hydrophobic poly(styrene).…”

“…For example, Satarkar et al numerically modeled heat transfer from an iron oxide nanoparticle/poly(ethylene glycol) disk. 45 Boundary conditions were specified from experimental SAR measurements generated via magnetic induction heating of the disk in air with a magnetic field strength, H, of 25kA m -1 operating at a frequency, f, of 293kHz. The SAR data was used to correlate a steady state disk surface temperature as a function of iron concentration.…”