pH Tunable Thin Film Gradients of Magnetic Polymer Colloids for MRI Diagnostics

Magnetic polymer colloids comprising of magnetite (Fe3O4) nanoparticles and Eudragit E100 were employed to fabricate thin film gradients and were investigated for in-vitro magnetic resonance imaging. Magnetic polymer colloids (MPC) and polyacrylic acid (PAA) with stimuli-responsive cationic and anionic functional groups respectively facilitate the formation of thin film gradients via layer by layer technique. The characteristics of films were controlled by changing the pH and level of the adsorbing solutions that lead to the development of gradient films having 5.5, 10.5 and 15.5 bilayers. Optical microscopy, scanning electron microscopy and magnetic force microscopy was carried out to determine the surface coverage of films. Surface wettability demonstrated the hydrophilicity of adsorbed colloids. The developed thin-film gradients were explored for in vitro magnetic resonance imaging that offers a point of care lab-on-chip as a dip-stick approach for ultrasensitive in-vitro molecular diagnosis of biological fluids.

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Magnetic Colloidal Particles in Combinatorial Thin-Film Gradients for Magnetic Resonance Imaging and Hyperthermia

Advances in Polymer Technology ◽

10.1155/2020/7163985 ◽

2020 ◽

Vol 2020 ◽

pp. 1-18

Author(s):

Sumera Khizar ◽

Nasir Mahmood Ahmad ◽

Hassan Saleem ◽

Muhammad Asif Hamayun ◽

Sadia Manzoor ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Thin Film ◽

Magnetic Resonance ◽

Colloidal Particles ◽

Aqueous Media ◽

Research Work ◽

Layer By Layer ◽

Resonance Imaging ◽

Signal Intensities ◽

T2 Weighted Images

A stable oil-in-water (O/W) magnetic emulsion was prepared by the emulsification of organic ferrofluid in an aqueous media, and its theranostic applications were investigated. The synthesis and characterization of the organic ferrofluid were carried out comprising of superparamagnetic maghemite nanoparticles with oleic acid coating stabilized in octane. Both exhibit spherical morphology with a mean size of 6 nm and 200 nm, respectively, as determined by TEM. Thermogravimetric analysis was carried out to determine the chemical composition of the emulsion. The research work described here is novel and elaborates the fabrication of thin-film gradients with 5, 10, 15, and 20 bilayers by layer-by-layer technique using polydimethyl diallyl ammonium chloride (PDAC) and prepared magnetic colloidal particles. The thin-film gradients were characterized for their roughness, morphology, and wettability. The developed gradient films and colloids were explored in magnetic resonance imaging (MRI) and hyperthermia. T1- and T2-weighted images and their corresponding signal intensities were obtained at 1.5 T. A decreasing trend in signal intensities with an increase in nanoparticle concentration in colloids and along the gradient was observed in T2-weighted images. The hyperthermia capability was also evaluated by measuring temperature rise and calculating specific absorption rates (SAR). The SAR of the colloids at 259 kHz, 327 kHz, and 518 kHz were found to be 156 W/g, 255 W/g, and 336 W/g, respectively. The developed magnetic combinatorial thin-film gradients present a significant potential for the future efficient simultaneous diagnostic and therapeutic bioapplications.

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Supermolecular theranostic capsules for pH-sensitive magnetic resonance imaging and multi-responsive drug delivery

Journal of Materials Chemistry B ◽

10.1039/c5tb01092f ◽

2015 ◽

Vol 3 (43) ◽

pp. 8499-8507 ◽

Cited By ~ 8

Author(s):

Di-Wei Zheng ◽

Qi Lei ◽

Si Chen ◽

Wen-Xiu Qiu ◽

Meng-Yi Liu ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Drug Delivery ◽

Magnetic Resonance ◽

Ph Sensitive ◽

Layer By Layer ◽

Resonance Imaging ◽

Macromolecular Drug Delivery ◽

Macromolecular Drug

Novel layer by layer (LBL) microcapsules for macromolecular drug delivery and pH-sensitive MR imaging were designed and tested both in vitro and in vivo.

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Dependence of Blood Clot Lysis on the Mode of Transport of Urokinase into the Clot - A Magnetic Resonance Imaging Study in Vitro

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648188 ◽

1991 ◽

Vol 65 (05) ◽

pp. 549-552 ◽

Cited By ~ 55

Author(s):

A Blinc ◽

G Planinšič ◽

D Keber ◽

O Jarh ◽

G Lahajnar ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Pressure Difference ◽

Volume Flow Rate ◽

Blood Clot ◽

Linear Regression Analysis ◽

Imaging Study ◽

Clot Lysis ◽

Resonance Imaging

SummaryMagnetic resonance imaging was employed to study the dependence of clot lysing patterns on two different modes of transport of urokinase into whole blood clots. In one group of clots (nonperfused clots, n1 = 10), access of urokinase to the fibrin network was possible by diffusion only, whereas in the other group (perfused clots, n2 = 10) bulk flow of plasma containing urokinase was instituted through occlusive clots by a pressure difference of 3 .7 kPa (37 cm H2O) across 3 cm long clots with a diameter of 4 mm. It was determined separately that this pressure difference resulted in a volume flow rate of 5.05 ± 2.4 × 10−2 ml/min through occlusive clots. Perfused clots diminished in size significantly in comparison to nonperfused ones already after 20 min (p <0.005). Linear regression analysis of two-dimensional clot sizes measured by MRI showed that the rate of lysis was more than 50-times faster in the perfused group in comparison to the nonperfused group. It was concluded that penetration of the thrombolytic agent into clots by perfusion is much more effective than by diffusion. Our results might have some implications for understanding the differences in lysis of arterial and venous thrombi.

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