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The number of therapeutic peptides for human treatment is growing rapidly. However, their development faces two major issues: the poor yield of large peptides from conventional solid-phase synthesis, and the intrinsically short serum half-life of peptides. To address these issues, we investigated a platform for the production of a recombinant therapeutic peptide with an extended serum half-life involving the site-specific conjugation of human serum albumin (HSA). HSA has an exceptionally long serum half-life and can be used to extend the serum half-lives of therapeutic proteins and peptides. We used glucagon-like-peptide 1 (GLP-1) as a model peptide in the present study. A “clickable” non-natural amino acid—p-azido-l-phenylalanine (AzF)—was incorporated into three specific sites (V16, Y19, and F28) of a GLP-1 variant, followed by conjugation with HSA through strain-promoted azide–alkyne cycloaddition. All three HSA-conjugated GLP-1 variants (GLP1_16HSA, GLP1_19HSA, and GLP1_28HSA) exhibited comparable serum half-lives in vivo. However, the three GLP1_HSA variants had different in vitro biological activities and in vivo glucose-lowering effects, demonstrating the importance of site-specific HSA conjugation. The platform described herein could be used to develop other therapeutic peptides with extended serum half-lives.

The use of injectable materials as a biofiller for soft tissue augmentation has been increasing worldwide. Levan is a biocompatible and inexpensive polysaccharide with great potential in biomaterial applications, but it has not been extensively studied. In this study, we evaluated the potential of levan as a new material for dermal fillers and prepared an injectable and physical levan-based hydrogel by combining levan with Pluronic and carboxymethyl cellulose (CMC). A sol state was prepared by mixing the polymers in a specific ratio at 4 °C for 2 days and the hydrogel was formed by increasing the temperature to 37 °C. The elastic modulus of the levan hydrogel was higher than that of a hyaluronic acid (HA)-based hydrogel. The SEM images of the levan hydrogel showed an interconnected porous structure, similar to the HA hydrogel. Levan showed non-cytotoxicity, enhanced cell proliferation, and higher amount of collagen synthesis in human dermal fibroblast cells compared to HA. The injected levan hydrogel was biocompatible and stable over 2 weeks in vivo, longer than the Pluronic F127 hydrogel or HA hydrogel. Also, the levan hydrogel showed a higher amount of collagen production than the HA hydrogel in vivo. More importantly, the levan hydrogel showed enhanced anti-wrinkle efficacy compared to the HA hydrogel in a wrinkle model mouse. Thus, the levan hydrogel with injectability, biocompatibility, and an anti-wrinkle effect has high potential as an alternative to existing commercial dermal fillers.

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Cell aggregates hold significant therapeutic promise for in vitro cell analysis, ex vivo tissue models, and in vivo cell therapy and tissue engineering. Traditional methods of making cell aggregates require long incubation times and can only produce three-dimensional-spheroid-shaped aggregates. We propose a novel method of making cell aggregates of diverse sizes and shapes using lipid-conjugated heparin. Shaking the cell suspension containing a small amount of lipid-conjugated heparin for approximately 30 min produced cell aggregates. This approach can be applied to any cell type, including stem cells, fibroblast cells, and T lymphocytes. The shape of biocompatible templates could modulate the shape of cell aggregates. In addition to layered, multicompartmental cell aggregates on template, template-free, tube-shaped cell aggregates could also be made. The cell aggregates formed were alive and maintained biological activities.

A paper-type sensor system was devised using an enzyme-loaded, artificial peroxidase-conjugated nanocarrier to maintain long-term stability with smartphone readout.

Conjugated polymer nanoparticles (CP NPs) that could absorb the first near-infrared (NIR-I) window have emerged as highly desirable therapeutic nanomaterials. Here, a quinoidalconjugated polymer (QCP), termed PQ, was developed as a novel class of therapeutic agents for photothermal therapy (PTT). Owing to its intrinsic quinoid structure, PQ exhibits molecular planarity and π-electron overlap along the conjugated backbone, endowing it with a narrow band gap, NIR-I absorption, and diradical features. The obtained PQ was coated with a poly(ethylene glycol) (PEG) moiety, affording nanosized and water-dispersed PQ nanoparticles (PQ NPs), which consequently show a high photothermal conversion efficiency (PCE) of 63.2%, good photostability, and apparent therapeutic efficacy for both in vitro and in vivo PTTs under an 808 nm laser irradiation. This study demonstrates that QCPs are promising active agents for noninvasive anticancer therapy using NIR-I light.

No abstract