DNA-templated self-assembly of bradykinin into bioactive nanofibrils

Bradykinin (BK) is a peptide hormone that plays a crucial role in blood pressure control, regulates inflammation in the human body, and has recently been implicated in the pathophysiology of COVID-19. In this study, we report a strategy for fabricating highly ordered 1D nanostructures of BK using DNA fragments as a template for self-assembly. We have combined synchrotron small-angle X-ray scattering and high-resolution microscopy to provide insights into the nanoscale structure of BK-DNA complexes, unveiling the formation of ordered nanofibrils. Fluorescence assays hint that BK is more efficient at displacing minor-groove binders in comparison with base-intercalant dyes, thus, suggesting that interaction with DNA strands is mediated by electrostatic attraction between cationic groups at BK and the high negative electron density of minor-grooves. Our data also revealed an intriguing finding that BK-DNA complexes can induce a limited uptake of nucleotides by HEK-293t cells, which is a feature that has not been previously reported for BK. Moreover, we observed that the complexes retained the native bioactivity of BK, including the ability to modulate Ca²⁺ response into endothelial HUVEC cells. Overall, the findings presented here demonstrate a promising strategy for the fabrication of fibrillar structures of BK using DNA as a template, which keep bioactivity features of the native peptide and may have implications in the development of nanotherapeutics for hypertension and related disorders.

Multicharged cyclodextrin supramolecular assemblies

Multicharged cyclodextrin (CD) supramolecular assemblies, including those based on positively/negatively charged modified mono-6-deoxy-CDs, per-6-deoxy-CDs, and random 2,3,6-deoxy-CDs, as well as parent CDs binding positively/negatively charged guests, have been extensively applied in chemistry, materials science, medicine, biological science, catalysis, and other fields. In this review, we primarily focus on summarizing the recent advances in positively/negatively charged CDs and parent CDs encapsulating positively/negatively charged guests, especially the construction process of supramolecular assemblies and their applications. Compared with uncharged CDs, multicharged CDs display remarkably high antiviral and antibacterial activity as well as efficient protein fibrosis inhibition. Meanwhile, charged CDs can interact with oppositely charged dyes, drugs, polymers, and biomacromolecules to achieve effective encapsulation and aggregation. Consequently, multicharged CD supramolecular assemblies show great advantages in improving drug-delivery efficiency, the luminescence properties of materials, molecular recognition and imaging, and the toughness of supramolecular hydrogels, in addition to enabling the construction of multistimuli-responsive assemblies. These features are anticipated to not only promote the development of CD-based supramolecular chemistry but also contribute to the rapid exploitation of these assemblies in diverse interdisciplinary applications.

Polyanionic Cyclodextrin Induced Supramolecular Nanoparticle

Ionizable cyclodextrins have attracted increasing attention in host–guest chemistry and pharmaceutical industry, mainly due to the introduction of favorable electrostatic interactions. The ionizable cyclodextrins could not only enhance its own solubility but also induce oppositely charged guests to form more stable complex. However, the aggregation induced by charged cyclodextrins has rarely been reported. In this work, guided by the concept of molecular-induced aggregation, a series of carboxyl modified cyclodextrins were synthesized via “click” and hydrolysis reaction. Then, UV-vis spectrum was used to investigate the aggregating behaviors induced by these cyclodextrins towards the cationic guest molecules. The results showed that only the hepta-carboxyl-β-cyclodextrin could induce the guest molecules to self-assemble into supramolecular spherical nanoparticles. Meanwhile, it could form stable inclusion complex with amantadine, a drug for anti-Parkinson and antiviral. The assembly behaviors were investigated by dynamic light scattering, scanning electron microscope, atomic force microscope, transmission electron microscope and NMR spectroscopy. The supramolecular nanoparticles induced by hepta-carboxyl-β-CD and its inclusion with amantadine could be used to encapsulate the model drug and achieve its controlled releasing behaviors.

Bioactive clusters promoting cell penetration and nucleic acid complexation for drug and gene delivery applications: from designed to self-assembled and responsive systems

Recent developments in the (self-)assembly of cationic clusters promoting nucleic acids complexation and cell penetration open the door to applications in drug and gene delivery.

Effect of head/tail groups on molecular induced aggregation of polycationic cyclodextrin towards anionic surfactants

A polycationic cyclodextrin significantly decreased the critical aggregation concentrations of anionic surfactants with different head/tail groups by a factor of 14–467 through the molecular induced aggregation.

Construction, Enzyme Response, and Substrate Capacity of a Hyaluronan-Cyclodextrin Supramolecular Assembly

A supramolecular assembly was constructed with a cationic cyclodextrin (EICD) and native hyaluronan (HA). The cationic carboxylic ester pendants on HA support hyaluronidase (HAase)-responsive sites and the EICD supports artificial carboxylic esterase responsive sites. Substrate-binding models were investigated by using environment-sensitive fluorescence probes 2-p-toluidino-6-naphthalenesulfoniate sodium (2,6-TNS) and thioflavin T (ThT). On a HA/EICD assembly, EICD was able to bind an anionic substrate and HA and EICD constructed the cationic substrate binding site together. This assembly could be used as a sequential dual-substrate carrier.

Hyaluronan/Ru(ii)-cyclodextrin supramolecular assemblies for colorimetric sensor of hyaluronidase activity

A hyaluronidase-induced colorimetric change was found in a hyaluronan/Ru(ii)-cyclodextrin supramolecular assembly under a laser (532 nm) irradiation.