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Encapsulation thermodynamics of a guest molecule by self-assembled rosette nanotubes (RNTs) was investigated using the statistical mechanical theory of molecular liquids also known as 3D-RISM theory. Ferrocene was chosen as a guest molecule because it is a good mimic for a small drug molecule in terms of logP value. The present computational study predicts that ferrocene can penetrate the channel of all three RNTs examined, however, the potential of mean force profile along the RNT channel suggested that RNT that has the smallest channel diameter has relatively high potential barrier for uptake and release of ferrocene, and therefore it was suggested that this could be a suitable mechanism to trap (during self-assembly) and release (during disassembly) a drug candidate. This work suggests also that tuning the RNT channel dimensions and chemistry should allow us to develop a palette of RNT delivery systems for a variety of drugs. [ABSTRACT FROM AUTHOR]

Describes the supramolecular processes for the self-assembly of the helical rosette nanotubes. Formulation of covalent polymeric systems; Transfer of molecular chirality into oligomeric systems; Role of chiral promoters in the transfer of molecular chirality.

A new strategy to access rosette nanotubes with increased inner diameter is presented and demonstrated through the synthesis and self-assembly studies of a tricyclic variant of the Lehn–Mascal G∧C base. [ABSTRACT FROM AUTHOR]

Abstract: Rosette nanotubes (RNTs) are discrete nanostructures self-assembled from a guanine–cytosine hybrid motif (G∧C) under aqueous conditions. These materials have substantial design flexibility and a range of applications, which are partly attributed to their diverse surface functionalization. Given the potential for interesting properties resulting from a metal-RNT construct, here we describe an oxorhenium-functionalized RNT. More specifically, we present the synthesis of a twin G∧C motif expressing the mercaptoacetyl triglycine (MAG3) ligand. We then examine the chelation reaction of the MAG3 with ReOCl3(PPh3)2 and self-assemble the resulting ReO-MAG3-G∧C conjugate into RNTs under DMSO and aqueous conditions. [Copyright &y& Elsevier]

Abstract: Progress toward the synthesis of guanine–cytosine (GΛC) oligonucleotides for the spontaneous self-assembly of rosette nanotubes (RNTs) with predefined length is described. Highlighted is the synthesis of the β-glycoside functionalized GΛC base along with a new nitrogen protecting group strategy that is compatible with Boc and Bn groups. [ABSTRACT FROM AUTHOR]

Abstract: An RGDSK (Arg-Gly-Asp-Ser-Lys) modified rosette nanotube (RNT) hydrogel composite with unique surface chemistry and favorable cytocompatibility properties for bone repair was developed and investigated. The RNTs are biologically inspired nanomaterials obtained through the self-assembly of a DNA base analog (G∧C base) with tailorable chemical functionality and physical properties. In this study, a cell-adhesive RGDSK peptide was covalently attached to the G∧C base, assembled into RNTs, and structurally characterized by 1H/13C NMR spectroscopy, mass spectrometry, and electron microscopy. Importantly, results showed that the RGDSK modified RNT hydrogels caused around a 200% increase in osteoblast (bone-forming cell) adhesion relative to hydrogel controls. In addition, osteoblast proliferation was enhanced on RNT hydrogels compared to hydrogel controls after 3 days, which further confirmed the promising cytocompatibility properties of this scaffold. When analyzing the mechanism of increased osteoblast density on RNT hydrogels, it was found that more fibronectin (a protein which promotes osteoblast adhesion) adsorption occurred on RNT coated hydrogels than uncoated hydrogels. As osteoblast adhesion was greatly enhanced on RNT coated hydrogels compared to poly l-lysine and collagen coated hydrogels, this study indicated that not only the surface chemistry was important in improving osteoblast density (via lysine or RGD groups functionalized on RNTs), but also the biomimetic nanoscale properties of RNTs provided a cell-favorable environment. These results warrant further studies on RNTs in hydrogels for better bone tissue regeneration. [Copyright &y& Elsevier]