One-Step Synthesis of Single-Stranded DNA-Bridged Iron Oxide Supraparticles as MRI Contrast Agents

Abstract

Despite progress on DNA-assembled nanoparticle (NP) superstructures, their complicated synthesis procedures hamper their potential biomedical applications. Here, we present an exceptionally simple strategy for the synthesis of single-stranded DNA (ssDNA) assembled Fe 3 O 4 supraparticles (DFe-SPs) as magnetic resonance contrast agents. Unlike traditional approaches that assemble DNAconjugated NPs via Watson−Crick hybridization, our DFe-SPs are formed with a high yield through one-step synthesis and assembly of ultrasmall Fe 3 O 4 NPs via ssDNA-metal coordination bridges. We demonstrate that the DFe-SPs can efficiently accumulate into tumors for sensitive MR imaging. By virtue of reversible DNA-metal coordination bridges, the DFe-SPs could be disassembled into isolated small NPs in vivo, facilitating their elimination from the body. This work opens a new avenue for the ssDNA-mediated synthesis of superstructures, which expands the repertoire of DNAdirected NP assembly for biomedical applications.

DNA‐Dependent Prussian Blue Nanoflowers for Biosensing, Catalysis and Imaging

“…As shown in Figure 4h,i, the peaks at 707.8 and 720.6 eV are corresponded to Fe 2p 3/2 and Fe 2p 1/2 of Fe II , and the peaks at 708.3 and 722.7 eV are indexed to Fe 2p 3/2 and Fe 2p 1/2 of Fe III . [ 34 ] Relative contents of the fitting Fe states are listed in Table S1 (Supporting Information), from which the Fe II /Fe III ratios are calculated as 1.82 and 4.67 for PB nanocube and PB nanoflower, respectively. The increased ratio demonstrates that more Fe II is introduced to the PB nanoflowers, meaning that a large amount of Fe II is attracted by protonated C30.…”

“…[ 32,33 ] Hence, DNA has been used as a capping ligand for controlling morphology of nanomaterials in a sequence‐dependent manner. [ 34–38 ] Specifically, changing the DNA nucleobases can control the formation of gold/silver nanomaterials with various shapes and versatile properties in seed‐grown method.…”

Multi-compartment supracapsules made from nano-containers towards programmable release

“…for delivering drug from arteries to arterioles and capillaries. [55][56][57] In summary, the proposed microfluidic-assisted assembly strategy not only enables fine control over the formation of supracapsules, but also allows for a wide choice of building blocks. In the future, microfluidic assembly could be extended to nano-containers with various stimuli-responsive releases, endowing the resulting supracapsules with multiple release profiles, e.g.…”

Multifunctional Layered Double Hydroxides for Drug Delivery and Imaging

“…Paramagnetic cations, such as manganese [ 96 , 97 ] and gadolinium [ 98 , 99 ], and gadolinium chelates such as Gd(DTPA) [ 82 , 100 ] have been used as T 1 contrast agents, and the contrast in T 2 signals has been enhanced by superparamagnetic iron oxide [ 101 , 102 ].…”