The spontaneous assembly of nanoscale building blocks into continuous semipermeable membranes is a key requirement for the structuration of synthetic protocells.Engineering the functionality and programmability of these building units provides a step towards more complex cell-like entities with adaptive membrane properties. Inspired by the central role of protein (lectin)-carbohydrate interactions in cellular recognition and adhesion, we fabricate semipermeable polysaccharide-polymer microcapsules (polysaccharidosomes) with intrinsic lectinbinding properties. We employ amphiphilic polysaccharide-polymer membrane building blocks endowed with intrinsic bio-orthogonal lectin-glycan recognition sites to facilitate the reversible non-covalent docking of functionalized polymer or zeolitic nanoparticles on the polysaccharidosomes. We show that the programmed attachment of enzyme-loaded nanoparticles
Having control over the supramolecular chirality through multiexternal stimulators provides many possibilities in realizing functional chiral materials. Herein, the supramolecular chirality of nanotwists comprising PA centered with 1,4-phenyldicarboxamide bearing two l/d-helicogenic alanine motifs and achiral COOH at each terminus of the alanine arms is modulated by solvent, temperature, and ultrasound. The modulations are mainly due to the hydrogen bonds among gelators and solvent-gelator interactions, resulting in changes of the molecular arrangement and subsequent self-assembled nanostructures. Typically, the gel of PA in ethyl acetate prepared by ultrasonication method exhibits thixotropic property due to the participation of ethyl acetate in the self-assembly process, resulting in relatively flexible and tolerant networks. This study provides a simplistic way to control the handedness of chiral nanostructures and a rational design of the self-assembly system with multistimuli-responsive supramolecular chirality.
Hydrazide derivatives
are known to display a wide range of biological
properties including antimicrobial activities, hence making them desirable
candidates for soft biomaterials. Herein, we report chiral supramolecular
coassembled hydrogels obtained from two phenylalanine gelators (L/DPF
and B2L/D) and two dicarbohydrazide molecules (pyridine-2,6-dicarbohydrazide
(PDH) and (2,2′-bipyridine)-5,5′-dicarbohydrazide (BDH))
that exhibited enhanced mechanical properties, chirality modulation,
and antimicrobial activity. Four lines of coassembled hydrogels were
obtained (i.e., L/DPF–PDH, L/DPF–BDH,
B2L/D–PDH, and B2L/D–BDH) through hydrogen bonding and
π–π stacking with some level of an interpenetrating
network, as revealed by the structural characterization analysis.
Mechanical properties were significantly improved, especially in the
case of hybrid gels involving BDH, with improved average elastic modulus
(G′) values of 3430 and 3167 Pa for DPF–BDH
and B2D–BDH (1:3, molar concentration) over 140 and 1680 Pa
for DPF and B2D gelators, respectively. This was attributed to the
improved π–π stacking and interpenetrating network
due to the bipyridine group and its ease to form fibrous precipitates
in the process of heating and cooling to room temperature. PDH, on
the other hand, was able to modulate chirality in the L/DPF gelator
due to its more planar and less bulky nature and showed antimicrobial
activity against Pseudomonas aeruginosa (Gram-negative). Interestingly, when PDH was coassembled with the
B2L/D gelator, the hybrid gels exhibited antimicrobial activity against Staphylococcus aureus (Gram-positive) and P. aeruginosa (Gram-negative) by virtue of a synergistic
effect of the gelator and the azomethine group of PHD. Hence, by moving
from bipyridine (BDH) to pyridine (PDH) as a core structure in the
hydrazide molecules, the resulting hybrid hydrogels exhibited desirable
properties of antimicrobial activity and improved mechanical attributes.
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