A versatile approach has been developed for the multiple labeling of oligonucleotides. First, three linkers as a H-phosphonate monoester derivative were condensed on a solid-supported T12 to introduce H-phosphonate diester linkages which were oxidized in the presence of propargylamine. Second, three galactosyl azide derivatives were conjugated to the solid-supported three-alkyne-modified T12 by a 1,3-cycloaddition so-called "click chemistry" in the presence of Cu(I) assisted by microwaves.

Carbohydrates and glycoconjugates play a major role in key biological events such as cell-cell recognition, pathogenesis, and inflammation. [1,2] As a consequence, there is a need to understand the structural parameters governing the recognition of carbohydrates by their receptors. This knowledge will be of use for both fundamental research and potential applications in diagnostics or therapeutics. However, research in this field is slowed by the wide diversity of carbohydrate structures and by the minute amounts of materials available for experimentation. The design of sensitive and highthroughput technologies for the characterization of oligosaccharide/protein interactions [3] is therefore emerging as an attractive tool for chemists and biochemists. Available techniques such as isothermal calorimetry, enzyme-linked lectin assay, and even crystallographic studies provide data on carbohydrate/protein interactions, but they are often limited by the amount of available material.Carbohydrate microarray technology [4][5][6][7][8][9][10][11][12][13][14][15][16] is a promising approach for probing carbohydrate/protein interactions, and it permits the simultaneous screening of a number of biological interactions with only minute amounts of material. A large family of carbohydrate derivatives has been designed for immobilization on surfaces by various means. [5][6][7][8][9][10][11][12][13][14] However, this technology has various limitations. Relative surface densities of bound ligands are often not assessed. A careful optimization of the orientation and the distance separating the carbohydrate probe from the surface is often required.The interactions of oligosaccharides with lectins are usually weak (mm range) and can be enhanced using the "cluster effect" with multivalent ligands. [17][18][19][20] In the latter case, the distance between the residues should be optimized for binding. [21][22][23] Finally, the syntheses of functionalized oligosaccharide ligands are labor intensive.We report herein an original approach for the surface immobilization of oligosaccharides using glycoconjugate molecules that present a DNA sequence for anchoring onto DNA chips through hybridization. This approach has been used in the field of protein microarrays, [24,25] but to our knowledge this is the first time that such a strategy has been reported in the field of glycoarrays.Several syntheses of glycoconjugated oligonucleotides have been reported, but none are suitable for introducing different carbohydrate moieties. [26][27][28] We designed a conjugate that incorporates carbohydrate residue(s) for interacting with a lectin, an oligonucleotide sequence for anchoring on the surface, and a fluorescent tag at the 5'-end for the determination of relative surface densities (Figure 1). These moieties were assembled through a combination of automated oligonucleotide synthesis, and amidative oxidation and 1,3-dipolar cycloaddition ("click" chemistry) performed on a solid support (Scheme 1).[29] We introduced either one or three saccharide residue...

Carbohydrates and glycoconjugates play a major role in key biological events such as cell-cell recognition, pathogenesis, and inflammation. [1,2] As a consequence, there is a need to understand the structural parameters governing the recognition of carbohydrates by their receptors. This knowledge will be of use for both fundamental research and potential applications in diagnostics or therapeutics. However, research in this field is slowed by the wide diversity of carbohydrate structures and by the minute amounts of materials available for experimentation. The design of sensitive and highthroughput technologies for the characterization of oligosaccharide/protein interactions [3] is therefore emerging as an attractive tool for chemists and biochemists. Available techniques such as isothermal calorimetry, enzyme-linked lectin assay, and even crystallographic studies provide data on carbohydrate/protein interactions, but they are often limited by the amount of available material.Carbohydrate microarray technology [4][5][6][7][8][9][10][11][12][13][14][15][16] is a promising approach for probing carbohydrate/protein interactions, and it permits the simultaneous screening of a number of biological interactions with only minute amounts of material. A large family of carbohydrate derivatives has been designed for immobilization on surfaces by various means. [5][6][7][8][9][10][11][12][13][14] However, this technology has various limitations. Relative surface densities of bound ligands are often not assessed. A careful optimization of the orientation and the distance separating the carbohydrate probe from the surface is often required.The interactions of oligosaccharides with lectins are usually weak (mm range) and can be enhanced using the "cluster effect" with multivalent ligands. [17][18][19][20] In the latter case, the distance between the residues should be optimized for binding. [21][22][23] Finally, the syntheses of functionalized oligosaccharide ligands are labor intensive.We report herein an original approach for the surface immobilization of oligosaccharides using glycoconjugate molecules that present a DNA sequence for anchoring onto DNA chips through hybridization. This approach has been used in the field of protein microarrays, [24,25] but to our knowledge this is the first time that such a strategy has been reported in the field of glycoarrays.Several syntheses of glycoconjugated oligonucleotides have been reported, but none are suitable for introducing different carbohydrate moieties. [26][27][28] We designed a conjugate that incorporates carbohydrate residue(s) for interacting with a lectin, an oligonucleotide sequence for anchoring on the surface, and a fluorescent tag at the 5'-end for the determination of relative surface densities (Figure 1). These moieties were assembled through a combination of automated oligonucleotide synthesis, and amidative oxidation and 1,3-dipolar cycloaddition ("click" chemistry) performed on a solid support (Scheme 1).[29] We introduced either one or three saccharide residue...

The design of smart nonviral vectors for gene delivery is of prime importance for the successful implementation of gene therapies. In particular, degradable analogues of macromolecules represent promising targets as they would combine the multivalent presentation of multiple binding units that is necessary for achieving effective complexation of therapeutic oligonucleotides with the controlled degradation of the vector that would in turn trigger drug release. Toward this end, we have designed and synthesized hybrid polyacylhydrazone-based dynamic materials that combine bis-functionalized cationic monomers with ethylene oxide containing monomers. Polymer formation was characterized by (1) H and DOSY NMR spectroscopy and was found to take place at high concentration, whereas macrocycles were predominantly formed at low concentration. HPLC monitoring of solutions of these materials in aqueous buffers at pH values ranging from 5.0 to 7.0 revealed their acid-catalyzed degradation. An ethidium bromide displacement assay and gel electrophoresis clearly demonstrated that, despite being dynamic, these materials are capable of effectively complexing dsDNA in aqueous buffer and biological serum at N/P ratios comparable to polyethyleneimine polymers. The self-assembly of dynamic covalent polymers through the incorporation of a reversible covalent bond within their main chain is therefore a promising strategy for generating degradable materials that are capable of establishing multivalent interactions and effectively complexing dsDNA in biological media.

Previous studies have demonstrated that some selected amino monoacids and amino diacids can function as leaving groups in the polymerase‐catalyzed incorporation of deoxynucleotides into DNA. Among these, the iminodiacetic acid phosphoramidate of deoxyadenosine monophosphate (IDA‐dAMP) represents an interesting example, as it could overcome some of the problems observed when using L‐aspartic acid as the leaving group, that is, poor chain elongation. We have now synthesized and evaluated a series of IDA‐dAMP analogues that bear either an extended aliphatic chain in the amino acid function, or a phosphonic acid moiety (substituting for the carboxylic acid function). Among these compounds, the nucleotide with an iminodipropionic acid leaving group (IDP‐dAMP) was identified as the best substrate; the excellent single incorporation (91 % conversion to a P+1 strand at 50 μM) was at a substrate concentration ten times lower than that used for IDA‐dAMP). This nucleotide also presented improved kinetics and elongation capability compared to IDA‐dAMP. The analogues with T, G, and C base moieties were also investigated for their incorporation ability with HIV‐1 RT. The incorporation efficiency was found to decrease in the order A>T>G>C. The properties of the iminodipropionic acid as the leaving group surpass those of previously evaluated leaving groups; this acid will be a prime candidate for in vivo testing.

Dynamic covalent polymers made from modified amino acids complex nucleic acids and deliver siRNA in living cells.

Bioactive low-molecular-weight compounds are actively pursued, as an alternative to macromolecules, for biomedical applications such as drug and gene delivery. However, achieving effective biomolecular surface recognition with small molecules is a considerable challenge. We review herein recent progresses that have been made in the identification of bioactive cationic clusters that promote cell penetration and nucleic acid complexation and vectorisation. We further emphasize the emerging use of self-assembly processes, based on supramolecular interactions and/or dynamic covalent chemistry, for generating bioactive cationic clusters. Interestingly, the introduction of molecular and/or supramolecular dynamics endows reversibility to the multivalent recognition processes, thereby paving the way toward the development of "smart" adaptive and responsive devices that emulate the behaviour of natural systems for the dynamic control of bioactivity.

Cage compounds are very attractive structures for a wide range of applications and there is ongoing interest in finding effective ways to access such kinds of complex structures, particularly those possessing dynamic adaptive features. Here we report the accessible synthesis of new type of organic cage architectures, possessing two different dynamic bonds within one structure: hydrazones and disulfides. Implementation of three distinct functional groups (thiols, aldehydes and hydrazides) in the structure of two simple building blocks resulted in their spontaneous and selective self-assembly into aromatic cage-type architectures. These organic cages contain up to ten components linked together by twelve reversible covalent bonds. The advantage provided by the presented approach is that these cage structures can adaptively self-sort from a complex virtual mixture of polymers or macrocycles and that dynamic covalent chemistry enables their deliberate disassembly through controlled component exchange.