Manuel C. Martos-Maldonado

Polymer materials endowed with hetero-complementary carboxylate and amidinium supramolecular functions can be generated either by solution or by surface grafting.

Noncovalent binding of biopharmaceuticals to human serum albumin protects against enzymatic degradation and renal clearance. Herein, we investigated the effect of mono- or divalent small-molecule albumin binders for half-life extension of peptides. For proof-of-principle, the clinically relevant glucagon-like peptide 1 (GLP-1) was functionalized with diflunisal, indomethacin, or both. In vitro, all GLP-1 analogues had subnanomolar GLP-1 receptor potency. Surface plasmon resonance revealed that both small molecules were able to confer albumin affinity to GLP-1 and indicated that affinity is increased for divalent analogues. In lean mice, the divalent GLP-1 analogues were superior to monovalent analogues with respect to control of glucose homeostasis and suppression of food intake. Importantly, divalent GLP-1 analogues showed efficacy comparable to liraglutide, an antidiabetic GLP-1 analogue that carries a long-chain fatty acid. Finally, pharmacokinetic investigations of a divalent GLP-1 analogue demonstrated a promising gain in circulatory half-life and absorption time compared to its monovalent equivalent.

The rational design of a well‐defined protein‐like tertiary structure formed by small peptide building blocks is still a formidable challenge. By using peptide–oligonucleotide conjugates (POC) as building blocks, we present the self‐assembly of miniature coiled‐coil α‐helical peptides guided by oligonucleotide duplex and triplex formation. POC synthesis was achieved by copper‐free alkyne–azide cycloaddition between three oligonucleotides and a 23‐mer peptide, which by itself exhibited multiple oligomeric states in solution. The oligonucleotide domain was designed to furnish a stable parallel triplex under physiological pH, and to be capable of templating the three peptide sequences to constitute a small coiled‐coil motif displaying remarkable α‐helicity. The formed trimeric complex was characterized by ultraviolet thermal denaturation, gel electrophoresis, circular dichroism (CD) spectroscopy, small‐angle X‐ray scattering (SAXS), and molecular modeling. Stabilizing cooperativity was observed between the trimeric peptide and the oligonucleotide triplex domains, and the overall molecular size (ca. 12 nm) in solution was revealed to be independent of concentration. The topological folding of the peptide moiety differed strongly from those of the individual POC strands and the unconjugated peptide, exclusively adopting the designed triple helical structure.

Glycobiology is the comprehensive biological investigation of carbohydrates. The study of the role and function of complex carbohydrates often requires the attachment of carbohydrates to surfaces, their tagging with fluorophores, or their conversion into natural or non‐natural glycoconjugates, such as glycopeptides or glycolipids. Glycobiology and its “omics”, glycomics, require easy and robust chemical methods for the construction of these glycoconjugates. This review gives an overview of the rapidly expanding field of chemical reactions that selectively convert unprotected carbohydrates into glycoconjugates through the anomeric position. The discussion is divided in terms of the anomeric bond type of the newly formed glycoconjugates, including O‐, N‐, S‐, and C‐glycosides.

Peptide-based structures can be designed to yield artificial proteins with specific folding patterns and functions. Template-based assembly of peptide units is one design option, but the use of two orthogonal self-assembly principles, oligonucleotide triple helix and a coiled coil protein domain formation have never been realized for de novo protein design. Here, we show the applicability of peptide–oligonucleotide conjugates for self-assembly of higher-ordered protein-like structures. The resulting nano-assemblies were characterized by ultraviolet-melting, gel electrophoresis, circular dichroism (CD) spectroscopy, small-angle X-ray scattering and transmission electron microscopy. These studies revealed the formation of the desired triple helix and coiled coil domains at low concentrations, while a dimer of trimers was dominating at high concentration. CD spectroscopy showed an extraordinarily high degree of α-helicity for the peptide moieties in the assemblies. The results validate the use of orthogonal self-assembly principles as a paradigm for de novo protein design.

Oxidative stress arises when the antioxidant capacity of cells to clean the excess production of reactive oxygen species (ROS) decreases. Several human diseases seem to be related with an increment in the oxidative stress. In this regard, GSH present in the cells works by neutralizing ROS and other xenobiotics through the glutathione S-transferase (GST) enzyme. Thus, the level of expression of GST is an important factor in determining the sensitivity of cells to toxic chemicals or xenobiotic compounds. Therefore, the detection of GST levels is fundamental in the clinical diagnosis of ROS-related diseases. Here, we describe a methodology, based on the voltammetric properties of the ferrocene group (used as electrochemical probe), which can be applied for selective detection of GST levels in human cells. The electrochemical signal measured is associated to the specific interaction of a ferrocenyl-GSH derivate with the G- and H-sites of this enzyme.

Three novel gold nanoparticles containing multiple long, flexible linkers decorated with lactose, β-cyclodextrin, and both simultaneously have been prepared. The interaction of such nanoparticles with β-d-galactose-recognizing lectins peanut agglutinin (PNA) and human galectin-3 (Gal-3) was demonstrated by UV–vis studies. Gal-3 is well-known to be overexpressed in several human tumors and can act as a biorecognizable target. This technique also allowed us to estimate their loading capability toward the anticancer drug methotrexate (MTX). Both results make these glyconanoparticles potential site-specific delivery systems for anticancer drugs.

The convenient preparation of two types of water‐soluble gold nanoparticles coated with mannose–ferrocene conjugates is reported herein. The preparation involved the use of unsymmetrical 1,1′‐bis‐substituted ferrocene building blocks that allowed their sequential orthogonal coupling with propargyl α‐D‐mannopyranoside and disulfide‐functionalized linkers used to anchor the mannose–ferrocene conjugate to the metal surface. The nanoparticles differ in the way the linker is bound to the ferrocene cyclopentadienyl ring: Either through an amide bond or a triazolylmethyl group. Although the former were unstable in water under exposure to light but stable in darkness, the latter were stable under both conditions. The mannose–ferrocene‐coated gold nanoparticles exhibited sensing abilities towards mannose‐binding lectin concanavalin A by both optical and electrochemical methods, based on the surface‐plasmon‐resonance (SPR)‐shift properties of the metal and the electrochemical activity of the ferrocene moiety, respectively. Moreover, they could be used to detect concanavalin A with high sensitivity in the low nanomolar range by electrochemical methods. A comparison of their redox‐sensing abilities with those reported for mono‐ and bivalent mannose–ferrocene conjugates revealed that the multivalent presentation of both mannose and ferrocene units led to a remarkable enhancement of sensitivity, the limit of detection being at least three orders of magnitude lower than for the single conjugates.