Chelator-Free Conjugation of ^99mTc and Gd³⁺ to PEGylated Nanographene Oxide for Dual-Modality SPECT/MR Imaging of Lymph Nodes

Abstract

PEGylated ultrasmall nanographene oxide (usNGO-PEG) has exhibited a great potential in nanotheranostics due to its newly discovered physicochemical properties derived from the rich functional groups and bonds. Herein, we developed a general, simple, and kitlike preparation approach for Tc- and Gd-anchored NGO-PEG using a chelator-free strategy. In this strategy, [Tc(CO)(OH)] (abbreviated to Tc) and GdCl were mixed with usNGO-PEG to yield Tc- and Gd-usNGO-PEG via the synergistic coordination of N and O atoms from NGO and PEG withTc and Gd without additional exogenous chelators. Under optimized conditions, the nanoprobes Tc- and Gd-usNGO-PEG were reliably prepared with high yields and good stability. Serial comparative experiments of the labeling yield, the measurements of -NH density and ζ-potentials, and various characterizations including energy-dispersive X-ray analysis spectroscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy demonstrated that both usNGO and PEG synergistically provide the electron-donating atoms O and N to coordinate with Tc and Gd to form stable nanocomplexes. Furthermore, both Tc- and Gd-usNGO-PEG exhibited excellent in vivo imaging of lymph nodes using single-photon emission computed tomography/computed tomography (SPECT/CT) and magnetic resonance (MR) imaging after local injection. Therefore, these results showed the successful establishment ofTc- and Gd-anchored usNGO-PEG using a chelator-free strategy and the potential of multimodality SPECT/CT and MR imaging of lymph nodes.

Formulation of Sugar/Hydrogel Inks for Rapid Thermal Response 4D Architectures with Sugar-derived Macropores

“…1a-c). The addition of alginate chains was intended not only to increase the viscosity of the ink but also to enable a double-network hydrogel in the printed structure after ionic cross-linking to improve its mechanical strength and toughness 7,32 .…”

“…A bilayer consisting of two kinds of hydrogels can bend in different directions, depending on the swelling/shrinking properties of each polymer. PNIPAAm is a typical temperature-sensitive polymer that shrinks at temperatures above a lower critical solution temperature (LCST) of ~32 °C whereas PAAm exhibits no substantial change 7 . Immersion in warm water leads to contraction of the thermoresponsive PNIPAAm and deformation of the bilayer, causing it to bend (Fig.…”

“…Three-dimensional (3D) printing of soft materials, such as hydrogels, elastomers, and conductive polymer composites, is an attractive approach in materials science, tissue engineering, soft robotics, and flexible electronics [1][2][3][4][5][6] . Structures 3D printed from stimuli-responsive hydrogels can undergo reversible volume-phase transitions in response to environmental changes, such as changes in temperature, pH, electric field, and light, making these materials highly interesting research targets [7][8][9][10][11] . By taking advantages of the reversible and repeatable mechanical movements induced by abrupt volume changes in hydrogels in response to external stimuli, one can use stimuli-responsive hydrogels to control the mechanical actions of soft actuators.…”

“…In this regard, a fast rate of volume change, particularly for stimuli-responsive hydrogels which undergo volume expansion upon hydration, is vital for the widespread application of 4D printing 20 . However, most polymer actuators suffer from relatively slow and small-scale movements [7][8][9]12,13 , and they involve complex preparation procedures, such as multistep lithography. The ability to manufacture polymer actuators by using 3D printing would enable easy fabrication and programmable shape morphing by design.…”

PAMAM Dendrimer‐Based Nanodevices for Nuclear Medicine Applications

“…It usually utilizes radioactive probes to capture information for early detection of cancer and monitoring of cancer progression and treatment outcomes. Due to the common drawbacks associated with the small molecular radioisotopes used in clinics, such as short imaging time, renal toxicity at a relatively high concentration, and non‐specificity, the rapid development of nanomedicine and nanotechnology has enabled the generation of various functional nanoprobes for nuclear medicine imaging, computed tomography (CT), and magnetic resonance (MR) imaging, as well as imaging‐guided cancer therapeutics…”