Fluorochrome-Functionalized Nanoparticles for Imaging DNA in Biological Systems

Abstract

Attaching DNA binding fluorochromes to nanoparticles (NPs) provides a way of obtaining NPs that bind to DNA through fluorochrome mediated interactions. To obtain a nanoparticle (NP) that bound to the DNA in biological systems, we attached the DNA binding fluorochrome, TO-PRO 1 (TO), to the surface of the Feraheme (FH) NP, to obtain a fluorochrome-functionalized NP denoted TO-FH. When reacted with DNA in vitro, TO-FH formed microaggregates that were characterized by fluorescence, light scattering, and T2 changes. The formation of DNA/TO-FH microaggregates was also characterized by AFM, with microaggregates exhibiting a median size of 200 nm, and consisting of DNA and multiple TO-FH NPs whose individual diameters were only 25–35 nm. TO-FH failed to bind normal cells in culture, but treatment with chemotherapeutic agents or detergents yielded necrotic cells that bound TO-FH and vital fluorochromes similarly. The uptake of TO-FH by HT-29 xenografts (treated with 5-FU and oxaliplatin) was evident by surface fluorescence and MRI. Attaching multiple DNA binding fluorochromes to magnetic nanoparticles provides a way of generating DNA binding NPs that can be used to detect DNA detection by microaggregate formation in vitro, for imaging the DNA of necrotic cells in culture, and for imaging the DNA of a tumor treated with a chemotherapeutic agent. Fluorochrome functionalized NPs are a multimodal (magnetic and fluorescent), highly multivalent (n ≈ 10 fluorochromes/NP) nanomaterials useful for imaging the DNA of biological systems.

Heat-induced radiolabeling and fluorescence labeling of Feraheme nanoparticles for PET/SPECT imaging and flow cytometry

“…The chemical stability of CMD–iron oxide interaction permits the conversion of carboxyl groups to amines, as well as reaction with the NHS esters of fluorochromes (see below and refs. 28,29 ).…”

Imaging modalities using magnetic nanoparticles – overview of the developments in recent years

“…Another recent publication deals with the attachment of DNA-binding fluorochromes to nanoparticles. This showed that TO-PRO1 attached to Feraheme nanoparticles bound to DNA in vitro and formed microaggregates that were characterized by fluorescence, light scattering, and T 2 changes [70] .…”

“…Jarrett et al [59] : Development of a PET/MRI probe using superparamagnetic iron oxide McCarthy et al [60] : Development of thrombosis-specific molecular imaging agents Skaat and Margel [61] : Selective marking of A β 40 fibrils using superparamagnetic iron oxide Purushotham and Ramanujan [62] : Synthesis of composite nanomaterials for hyperthermia and drug release Nowostawska et al [64] : Analysis of porhyrin magnetic nanoparticle composite Huang et al [65] : Characterization of anti-α -fetoprotein mediated Fe 3 O 4 Yiu et al [66] : Development of Fe 3 O 4 -PEI-RITC with MR-fluorescence imaging and transfections capabilities Ren et al [67] : Investigation of the efficiency of Fe 3 O 4 combined with chemotherapy and hyperthermia for overcoming multidrug resistance Xu et al [68] : Synthesis of few-layer, carbon-coated, iron magnetic nanoparticles for controlled drug release and hypothermia Miyaki et al [69] : Analysis of multimodal magnetic nanoparticles-rhodamine B Cho et al [70] : Development of nanoparticles that bind to DNA through fluorochome-mediated interactions MPI Weaver et al [98] : Exploration of the signal from magnetic nanoparticles Goodwill et al [77] : Introduction of narrowband-MPI Ferguson et al [78] : Presentation of mathematical modeling results that show the dependence of core design on physical properties Knopp et al [79] : Simulation study on different trajectories moving the field-free point through the field-of-view Knopp et al [80] : Calculation of the system function using a model of the signal chain Knopp et al [81] : Demonstration of how the quality of the least-squares solution can be improved Knopp et al [82] : Investigation of the spatial resolution of magnetic particle imaging Rahmer et al [83] : Presentation of a detailed analysis of a measured system function Finas et al [84] : Investigation of superparamagnetic iron oxide and magnetic particle imaging as sentinel lymph node biopsy tracer Goodwill et al [85] : " Derive " of 2-D x-space signal equation and 2-D image equation Reeves and Weaver [86] : Development and validation of a stochastic dynamical model of rotating Brownian nanoparticles from a Langevin equation approach Haegele et al [87] : Test of various commercially available catheters, guide wires, and a catheter experimentally coated with SPIONs regarding signal characteristics using magnetic particle spectroscopy Ferguson et al …”

Synthesis, Functionalization, and Design of Magnetic Nanoparticles for Theranostic Applications

“…Ferrumoxtran-10 and Feraheme are of commercially available MRI agents coated with natural carbohydrate polymers. [318] Due to strong magnetic dipole-dipole attractions between MNPs, there is an innate tendency to aggregate. To overcome this, hydrophilic polymers such as starch and dextran ensure good aqueous dispersion of the MNPs.…”