•A trisaccharide repeating unit of the O-antigen from Burkholderia anthina and its dimer-hexasaccharide were synthesized via a highly convergent and efficient assembly strategy.•The α-1,2-linked disaccharide was successfully achieved by the armed-disarmed glycosylation strategy.•The synthetic oligosaccharide fragments are useful antigen targets for the development of O-antigen-based vaccines against B. anthina infectious disease.A trisaccharide repeating unit of the O-antigen from Burkholderia anthina, α-L-Rha-(1→2)-α-L-Rha-(1→2)-β-D-Gal-O(CH2)3NH2 (1), and its dimer, α-L-Rha-(1→2)-α-L-Rha-(1→2)-α-D-Gal-(1→3)-α-L-Rha-(1→2)-α-L-Rha-(1→2)-β-D-Gal-O(CH2)3NH2 (2), were synthesized via a highly convergent and efficient assembly strategy. Sequential glycosylation of galactosyl acceptor 6 with rhamnosyl thioglycoside 7, followed by condensation of the resulting disaccharide acceptor 9 with rhamnosyl imidate donor 10, gave the title molecule 1 after global deprotection. The title hexasaccharide 2 was assembled in a convergent [2+2+2] manner, in which α-1,2-linked disaccharide 12 was initially obtained by the coupling reaction of disarmed thiorhamnoside acceptor 15 with armed thiogalactoside donor 14. Sequential glycosylation of disaccharide acceptor 9 with thioglycoside donors 12 and 13 afforded the target compound 2 after global deprotection.

Lipoarabinomannan (LAM) is one of the major constituents of the Mycobacterium tuberculosis cell wall and an attractive molecular scaffold for antituberculosis drug and vaccine development. In this paper, a convergent strategy was developed for the synthesis of LAM oligosaccharides with an α-1,2-linked dimannopyranose cap at the nonreducing end. The strategy was highlighted by efficient coupling of separately prepared nonreducing end and reducing end oligosaccharides. Glycosylations were mainly achieved with thioglycoside donors, which gave excellent yields and stereoselectivity even for reactions between complex oligosaccharides. The strategy was utilized to successfully synthesize tetra-, hepta-, and undecasaccharides of LAM from d-arabinose in 10, 15, and 14 longest linear steps and 7.84, 7.50, and 2.59% overall yields, respectively. The resultant oligosaccharides with a free amino group at their reducing end were effectively conjugated with carrier proteins, including bovine serum albumin and keyhole limpet hemocyanin (KLH), via a bifunctional linker. Preliminary immunological studies on the KLH conjugates revealed that they could elicit robust antibody responses in mice and that the antigen structure had some influence on their immunological property, thus verifying the potential of the oligosaccharides for vaccine development and other immunological studies.

An analog of Mycobacterium tuberculosis lipoarabinomannan (LAM) has been synthesized containing the characteristic structures of all of its three major components; that is, a mannosylated phosphatidylinositol moiety, an oligomannan, and an oligoarabinan. A highly convergent strategy was developed that is applicable to the synthesis of other LAM analogs. The synthetic miniature LAM should be useful for various biological studies.

With the advances in the understanding of cell interactions with their microenvironments, biomaterials mimicking native microenvironments are being developed to display and deliver cell-regulatory signals in a precise and near-physiological fashion, which are used to regulate cell behavior and fate both in vitro and in vivo. Such biomaterials can provide the necessary microenvironmental cues based on chemistry, topography, mechanics, and molecule delivery. This has significantly promoted the applications of biomaterials to tissue engineering and disease treatment. This report has summarized the recent progress made in the field by focusing on native microenvironment-mimetic biomaterials utilized as tissue scaffolding and other implant devices. In particular, material properties that direct cellular behavior through controlled presentation of specific cues in time or in space, such as the material composition and material surface functionality, structure, topology, hydrophilicity/hydrophobicity, charge and energy, as well as the material topology density and mechanics, have been discussed in great detail. It is anticipated that the synergy of cell biology and modern material technologies will have a profound impact on the design and development of new generations of biomaterials.

•Naturally occurring tigogenin triglycoside 1a and three derivatives 1b–d were prepared via an efficient one-pot sequential glycosylation strategy.•Partially protected thiogalactosides bearing unprotected 2,4-OH or 4-OH groups were used to significantly simplify the target molecule synthesis.•CCK-8 assays against HeLa tumor cell indicated that synthetic saponins 1a–d exhibited significantly higher anti-tumor activities than the positive control cisplatin.An efficient synthesis of naturally occurring tigogenin triglycoside 1a and its three derivatives 1b–d bearing different carbohydrate moieties, as well as their antitumor activities, is described. Partially protected thiogalactosides bearing unprotected 2,4-OH or 4-OH groups were used to facilitate regioselective reactions for one-pot sequential multi-step glycosylation, which has significantly simplified the target molecule synthesis. The synthetic saponins 1a–d exhibited much higher anti-tumor activities than the positive control cisplatin against the human epithelial cervical cancer cell (HeLa) as evaluated by CCK-8 assay.

•The nHAC/CSH composite can be as an injectable bone repair material.•The L/S ratio and nHAC content have a significant effect on material degradability.•The degradability of bone materials can be regulated to match tissue repair.•The regulable degradability will further improve the workability of bone materials.The nHAC/CSH composite is an injectable bone repair material with controllable injectability and self-setting properties prepared by introducing calcium sulfate hemihydrate (CSH) into mineralized collagen (nHAC). When mixed with water, the nHAC/CSH composites can be transformed into mineralized collagen/calcium sulfate dihydrate (nHAC/CSD) composites. The nHAC/CSD composites have good biocompatibility and osteogenic capability. Considering that the degradation behavior of bone repair material is another important factor for its clinical applications, the degradability of nHAC/CSD composites was studied. The results showed that the degradation ratio of the nHAC/CSD composites with lower nHAC content increased with the L/S ratio increase of injectable materials, but the variety of L/S ratio had no significant effect on the degradation ratio of the nHAC/CSD composites with higher nHAC content. Increasing nHAC content in the composites could slow down the degradation of nHAC/CSD composite. Setting accelerator had no significant effect on the degradability of nHAC/CSD composites. In vivo histological analysis suggests that the degradation rate of materials can match the growth rate of new mandibular bone tissues in the implanted site of rabbit. The regulable degradability of materials resulting from the special prescriptions of injectable nHAC/CSH composites will further improve the workability of nHAC/CSD composites.

Analogs of the human CD52 and CD24 antigens carrying the common core structure of glycosylphosphatidylinositol (GPI) anchors and the intact polypeptide sequences of CD52 and CD24 were chemoenzymatically synthesized. CD52 and CD24 proteins were obtained by solid-phase peptide synthesis and then coupled to chemically synthesized GPI anchors under the influence of a bacterial enzyme, sortase A, to afford the target molecules in good yields.