The molecular framework Ag(tcm) (tcm(-) = tricyanomethanide) expands continuously in two orthogonal directions under hydrostatic compression. The first of its kind, this negative area compressibility behaviour arises from the flattening of honeycomb-like layers during rapid pressure-driven collapse of the interlayer separation.
Viral
and synthetic vectors for delivery of nucleic acids impacted
genetic nanomedicine by aiding the rapid development of the extraordinarily
efficient Covid-19 vaccines. Access to targeted delivery of nucleic
acids is expected to expand the field of nanomedicine beyond most
expectations. Both viral and synthetic vectors have advantages and
disadvantages. The major advantage of the synthetic vectors is their
unlimited synthetic capability. The four-component lipid nanoparticles
(LNPs) are the leading nonviral vector for mRNA used by Pfizer and
Moderna in Covid-19 vaccines. Their synthetic capacity inspired us
to develop a one-component multifunctional sequence-defined ionizable
amphiphilic Janus dendrimer (IAJD) delivery system for mRNA. The first
experiments on IAJDs provided, through a rational-library design combined
with orthogonal-modular accelerated synthesis and sequence control
in their hydrophilic part, some of the most active synthetic vectors
for the delivery of mRNA to lung. The second experiments employed
a similar strategy, generating, by a less complex hydrophilic structure,
a library of IAJDs targeting spleen, liver, and lung. Here, we report
preliminary studies designing the hydrophobic region of IAJDs by using
dissimilar alkyl lengths and demonstrate the unexpectedly important
role of the primary structure of the hydrophobic part of IAJDs by
increasing up to 90.2-fold the activity of targeted delivery of mRNA
to spleen, lymph nodes, liver, and lung. The principles of the design
strategy reported here and in previous publications indicate that
IAJDs could have a profound impact on the future of genetic nanomedicine.
Chiral (all-R)-cyclohexanohemicucurbit[8]uril binds anions in a 1 : 1 ratio in pure methanol like a molecular Pac-Man™ with remarkable selectivity based on the size, shape and charge distribution of the anion.
Chiral cyclohexanohemicucurbit[n]urils with multiple interaction sites induce chirality on planar zinc porphyrins and bind up to three porphyrin molecules.
Complexation of three (1[Formula: see text],2[Formula: see text]-2-aminocyclohexyl arylthioureas (aryl [Formula: see text] 3,5-bis(trifluoromethyl)phenyl; phenyl; 3,5-dimethylphenyl) as the guests to ZnTPP and ZnOEP hosts has been studied by means of UV-vis, CD spectroscopies and computational simulation. The complexation proceeds via coordination of the primary amino group to the zinc ion of the metalloporphyrin and induces a moderate circular dichroism signal in the Soret band of the porphyrins. The association constants increase with larger electron-withdrawing properties of the porphyrin host and larger electron-donating ability of the guest, indicating predominantly electrostatic (Lewis acid-base) character of the complexation. Computational study of the (1[Formula: see text],2[Formula: see text]-2-aminocyclohexyl-(3,5-bis(trifluoromethyl)phenyl)thiourea and ZnTPP complex revealed slight asymmetric distortion of the porphyrin plane caused by the chiral guest and additional [Formula: see text]–[Formula: see text] interactions between the host and guest molecules. The calculated CD spectrum for the same system reproduces the experimentally observed one.
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