Synthesis of Asp-based lactam cyclic peptides using an amide-bonded diaminodiacid to prevent aspartimide formation.

Asp-based lactam cyclic peptides are considered promising drug candidates. However, using Fmoc solid-phase peptide synthesis (Fmoc-SPPS) for these peptides also causes aspartimide formation, resulting in low yields or even failure to obtain the target peptides. Here, we developed a diaminodiacid containing an amide bond as a ß-carboxyl-protecting group for Asp to avoid aspartimide formation. The practicality of this diaminodiacid has been illustrated by the synthesis of lactam cyclic peptide cyclo[Lys9,Asp13] KIIIA7-14 and 1Y.

Upper Critical Solution Temperature Polyvalent Scaffolds Aggregate and Exterminate Bacteria.

Specific recognition and strong affinities of bacteria receptors with the host cell glycoconjugates pave the way to control the bacteria aggregation and kill bacteria. Herein, using aggregation-induced emission (AIE) molecules decorated upper critical solution temperature (UCST) polyvalent scaffold (PATC-GlcN), an approach toward visualizing bacteria aggregation and controlling bacteria-polyvalent scaffolds affinities under temperature stimulus is described. Polyvalent scaffolds with diblocks, one UCST block PATC of polyacrylamides showing a sharp UCST transition and typical AIE behavior, the second bacteria recognition block GlcN of hydrophilic glucosamine modified polyacrylamide, are prepared through a reversible addition and fragmentation chain transfer polymerization. Aggregated chain conformation of polyvalent scaffolds at temperature below UCST induces the aggregation of E. coli ATCC8739, because of the high density of glucosamine moieties, whereas beyond UCST, the hydrophilic state of the scaffolds dissociates the bacteria aggregation. The sweet-talking of bacteria toward the polyvalent scaffolds can be visualized by the fluorescent imaging technique, simultaneously. Due to the specific recognition of polyvalent scaffolds with bacteria, the photothermal agent IR780 loaded PATC-GlcN shows the targeted killing ability toward E. coli ATCC8739 in vitro and in vivo under NIR radiation.

Rapid and inexpensive blood typing on thermoplastic chips.

A portable and cost-effective colorimetric diagnostic device was fabricated for rapid ABO and Rh blood typing. Using microfluidic construction on a thermoplastic chip, blood antibodies were preloaded into a reaction channel and exposed to blood samples to initiate a haemagglutination reaction. Downstream high-aspect ratio filters, composed of 2 µm high microslits, block agglutinated red blood cells (RBCs) to turn the reaction channel red, indicating the presence of the corresponding blood antigen. Users manually actuate the blood sample using a simple screw pump that drives the solution through serpentine reaction channels and chaotic micromixers for maximum interaction of the preloaded antibodies with the blood sample antigens. Mismatched RBCs and antibodies elute from the channel into an outlet reservoir based on the rheological properties of RBCs with no colorimetric change. As a result, unambiguous blood typing tests can be distinguished by the naked eye in as little as 1 min. Blood disorders, such as thalassemia, can also be distinguished using the device. The required blood volume for the test is just 1 µL, which can be obtained by the less invasive finger pricking method. The low reagent consumption, manual driving force, low-cost of parts, high yield, and robust fabrication process make this device sensitive, accurate, and simple enough to use without specialized training in resource constrained settings.