DNA has proven of high utility to modulate the surface functionality of metal-organic frameworks (MOFs) for various biomedical applications. Nevertheless, current methods for preparing DNA-MOF nanoparticles rely on either inefficient covalent conjugation or specific modification of oligonucleotides. In this work, we report that unmodified oligonucleotides can be loaded on MOFs with high density (∼2500 strands/particle) via intrinsic, multivalent coordination between DNA backbone phosphate and unsaturated zirconium sites on MOFs. More significantly, surface-bound DNA can be efficiently released in either bulk solution or specific organelles in live cells when free phosphate ions are present. As a proof-of-concept for using this novel type of DNA-MOFs in immunotherapy, we prepared a construct of immunostimulatory DNA-MOFs (isMOFs) by intrinsically coordinating cytosine-phosphate-guanosine (CpG) oligonucleotides on biocompatible zirconium MOF nanoparticles, which was further armed by a protection shell of calcium phosphate (CaP) exoskeleton. We demonstrated that isMOFs exhibited high cellular uptake, organelle specificity, and spatiotemporal control of Toll-like receptors (TLR)-triggered immune responses. When isMOF reached endolysosomes via microtubule-mediated trafficking, the CaP exoskeleton dissolved in the acidic environment and in situ generated free phosphate ions. As a result, CpG was released from isMOFs and stimulated potent immunostimulation in living macrophage cells. Compared with naked CpG-MOF, isMOFs exhibited 83-fold up-regulation in stimulated secretion of cytokines. We thus expect this isMOF design with soluble CaP exoskeleton and an embedded sequential "protect-release" program provides a highly generic approach for intracellular delivery of therapeutic nucleic acids.
Lithium metal batteries (LMBs) are promising candidates for next‐generation energy storage due to their high energy densities on both weight and volume bases. However, LMBs usually undergo uncontrollable lithium deposition, unstable solid electrolyte interphase, and volume expansion, which easily lead to low Coulombic efficiency, poor cycling performance, and even safety hazards, hindering their practical applications for more than forty years. These issues can be further exacerbated if operated at high current densities. Here a stable lithium metal battery enabled by 3D porous poly‐melamine‐formaldehyde (PMF)/Li composite anode is reported. PMF with a large number of polar groups (amine and triazine) can effectively homogenize Li‐ion concentration when these ions approach to the anode surface and thus achieve uniform Li deposition. Moreover, the 3D structured anode can serve as a Li host to mitigate the volume change during Li stripping and plating process. Galvanostatic measurements demonstrate that the 3D composite electrode can achieve high‐lithium Coulombic efficiency of 94.7% at an ultrahigh current density of 10 mA cm−2 after 50 cycles with low hysteresis and smooth voltage plateaus. When coupled with Li4Ti5O12, half‐cells show enhanced rate capabilities and Coulombic efficiencies, opening great opportunities for high‐energy batteries.
of lithium metal batteries (LMBs). [3][4][5] Compared with intercalation compounds such as graphite in LIBs, lithium metal anode possesses an extremely high theoretical capacity of 3860 mA h g −1 with a very low redox potential (−3.04 V vs the standard hydrogen electrode), making it an attractive anode material to pair with highenergy conversion cathodes such as sulfur and oxygen. [6,7] Unfortunately, the application of lithium metal is full of challenges that have puzzled researchers for more than 40 years. [8] The most notorious one is that Li metal problematically forms dendrites during repeated cycling. [9] Owing to the multi-component solid electrolyte interphase (SEI) layer and uneven anode substrate, inhomogeneous lithium-ion flux is formed at the electrode/electrolyte interface, leading to nonuniform lithium eletrodeposition on the metal surface. The fresh metallic tip acts as an active site, which induces the ramified growth of lithium dendrite, resulting in cell short-circuit and low coulombic efficiency. This dendrite formation behavior can be much severe at high current densities. Another serious problem lies in electrode volume expansion originated from the repeated plating/ stripping process. [10,11] As a "hostless" electrode, lithium metal tends to be fully stripped when used in practical full cells and can hardly travel back to the same location during plating, causing mechanical instability of electrode/separator interface as well as internal stress fluctuation. As a result, the capacity of LMBs fades sharply during cycling.Over the past four decades, many up-and-coming strategies have been developed to enhance the electrochemical performance of Li metal anode and overcome the problems raised from uneven Li electrodeposition. These methods include doping electrolyte additives (Li halide, [12] ionic liquid, [13] and Cs +[14] ) and coating artificial SEIs (Li 3 PO 4 , [15] Cu 3 N, [16] LiF, [17] and Li alloy [18][19][20] ) on Li anode. More recently, researchers have focused on creating 3D scaffold/lithium metal composites as alternatives for common planar lithium. According to Chazalviel's model, the onset time of uneven deposition is inversely proportional to the current density (τ ≈ -2 J ). [21,22] Therefore, designing high-surface-area composite anode can lower J and thus prolong the cell lifetime. Based on this theory, Cu mesh, [23,24] Ni foam, [25] and other 3D conductive frameworks [26][27][28] have been developed to replace planar current The lithium metal battery (LMB) is among the most sought-after battery chemistries for high-energy storage devices. However, LMBs usually undergo uncontrollable lithium deposition and severe side reactions, which significantly impede their practical applications. Herein, a stable Al 2 O 3 -based inorganic framework with superlithiophilic lithium aluminum oxide (Li-Al-O) interphase is created via reacting Li with Al 2 O 3 nanoparticles. The Al 2 O 3 -based inorganic framework can serve as a stable Li "host," reducing the volume expansion during cell cyclin...
As one of the most promising next-generation safe and green energy storage technologies, aqueous Zn-ion batteries have attracted considerable attention in recent years.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.