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Neurological disorders are often debilitating conditions with no cure. The majority of current therapies are palliative rather than disease-modifying; therefore, new strategies for treating neurological disorders are greatly needed. mRNA-based therapeutics have great potential for treating such neurological disorders; however, challenges with delivery have limited their clinical potential. Lipid nanoparticles (LNPs) are a promising delivery vector for the brain, given their safer toxicity profile and higher efficacy. Despite this, very little is known about LNP-mediated delivery of mRNA into the brain. Here, we employ MC3-based LNPs and successfully deliver Cre mRNA and Cas9 mRNA/Ai9 sgRNA to the adult Ai9 mouse brain; greater than half of the entire striatum and hippocampus was found to be penetrated along the rostro-caudal axis by direct intracerebral injections of MC3 LNP mRNAs. MC3 LNP Cre mRNA successfully transfected cells in the striatum (∼52% efficiency) and hippocampus (∼49% efficiency). In addition, we demonstrate that MC3 LNP Cas9 mRNA/Ai9 sgRNA edited cells in the striatum (∼7% efficiency) and hippocampus (∼3% efficiency). Further analysis demonstrates that MC3 LNPs mediate mRNA delivery to multiple cell types including neurons, astrocytes, and microglia in the brain. Overall, LNP-based mRNA delivery is effective in brain tissue and shows great promise for treating complex neurological disorders.

Modulating the spin-crossover behaviour in porous coordination polymers is not only an excellent way to address the challenges associated with high-order data storage and processing, but the colour change involved in the process reveals their importance as thermal and optical sensors. Herein, we report the guest-induced regulation of the magnetic bi-stability in a Hofmann-type framework, {Fe(pina)[Pd(CN)4]} (1, pina = N-(pyridin-4-yl)isonicotinamide) from ∼26 K (for 1·3.6MeCN, complex 1), to ∼40 K (for 1·stb.4H2O, stb = stilbene, complex 2) by a subsequent change of the guest molecules from CH3CN to stilbene. While the electronic interactions stabilize the LS states through effective π⋯π stacking between the guest stilbene and the host layers, chemical pressure, i.e., the steric effect of the stilbene molecule, stabilizes the HS states, and the overall competition between them leads to the high thermal hysteresis. To explicate the spin crossover properties to be used as a potential thermal sensor, the guest-free nanoparticles of framework (1) were prepared using the reverse micelle method. Magnetic measurements reveal that the effective downsizing at the nanoscale results in a progressive downward shift with an incomplete gradual SCO behaviour, diminishing the hysteresis loop compared to the abrupt hysteretic transition found at the bulk phase. In addition, these nanoparticles are assimilated as free-standing thermochromic polymeric films as a proof of concept for thermal sensing device. The rationalization of the tunable SCO properties, along with the thermochromic behaviour, opens up a new strategy for the development of new π electron-responsive magnetic materials. [ABSTRACT FROM AUTHOR]

Spin crossover complexes that reversibly interconvert between two stable states imitate a binary state of 0 and 1, delivering a promising possibility to address the data processing concept in smart materials. Thus, a comprehensive understanding of the modulation of magnetic transition between high spin and low spin and the factors responsible for stabilizing the spin states is an essential theme in modern materials design. In this context, the present review attempts to provide a concise outline of the design strategy employed at the molecular level for fine‐tuning the spin‐state switching in FeII‐based Hofmann‐type coordination polymers and their effects on the optical and magnetic response. In addition, development towards the nanoscale architectures of HCPs, i. e. in terms of nanoparticles and thin films, are emphasized to bridge the gap between the laboratory and reality. [ABSTRACT FROM AUTHOR]

The rational design of multifunctional molecular components serves as the basis for designing materials with practical applications. "Electronic pyroelectricity," i.e., transient voltage or current generated by the temperature-dependent spontaneous polarization induced by electrons, plays a pivotal role in modern sensor and energy conversion devices. Entropically favorable dynamic electron transfer processes such as valence tautomerism (VT) or spin transition have recently been proven to modulate the degree of co-alignment of permanent dipoles, i.e., the polarization in a molecular crystal. Two recent studies by Sato and co-workers have outlined the fruitful ways to achieve electronic pyroelectricity at the macroscopic level incorporating an electronic redistribution strategy by combining a labile electronic structure with the crystal engineering of the molecular orientation in the crystal lattice. These breakthroughs, hard on the heels of each other, opened up a new route to overcome the formidable challenge of obtaining materials with significant and nearly constant pyroelectric coefficients over a wide temperature range. [ABSTRACT FROM AUTHOR]