The Royal Society of Chemistry最新文献

Granular hydrogels comprised of jammed, crosslinked microgels offer great potential as biomaterial scaffolds for cell-based therapies, including for cartilage tissue regeneration. As stiffness and porosity of hydrogels affect the phenotype of encapsulated cells and the extent of tissue regeneration, the design of tunable granular hydrogels to control and optimize these parameters is highly desirable. We hypothesized that chondrogenesis could be modulated using a granular hydrogel platform based on biocompatible, zwitterionic materials with independent intra- and inter-microgel crosslinking mechanisms. Microgels are made with mechanical fragmentation of photocrosslinked zwitterionic carboxybetaine acrylamide (CBAA) and sulfobetaine methacrylate (SBMA) hydrogels, and secondarily crosslinked in the presence of cells using horseradish peroxide (HRP) to produce cell-laden granular hydrogels. We varied the intra-microgel crosslinking density to produce microgels with varied stiffnesses (1-3 kPa) and swelling properties. These microgels, when resuspended at the same weight fraction and secondarily crosslinked, resulted in granular hydrogels with distinct porosities (5-40%) due to differing swelling properties. The greatest extent of chondrogenesis was achieved in scaffolds with the highest microgel stiffness and highest porosity. However, when scaffold porosity was kept constant and just microgel stiffness varied, cell phenotype and chondrogenesis were similar across scaffolds. These results indicate the dominant role of granular scaffold porosity on chondrogenesis, whereas microgel stiffness appears to play a relatively minor role. These observations are in contrast to cells encapsulated within conventional bulk hydrogels, where stiffness has been shown to significantly affect chondrocyte response. In summary, we introduce chemically-defined, zwitterionic biomaterials to fabricate versatile granular hydrogels allowing for tunable scaffold porosity and microgel stiffness to study and influence chondrogenesis.

Retraction of 'Glycolipid nanotube templates for the production of hydrophilic/hydrophobic and left/right-handed helical polydiacetylene nanotubes' by Naohiro Kameta et al., Chem. Commun., 2021, 57, 464-467, https://doi.org/10.1039/D0CC07387C.

Treating sunburn and other UV-induced skin damage issues remains a significant challenge in the field of dermatology. In this study, we synthesized a highly bioactive recombinant type III collagen (rCol III) to accelerate the healing of UV-damaged skin. The high-purity rCol III demonstrated excellent biocompatibility and bioactivity, significantly promoting the adhesion, proliferation, and migration of HFF-1 cells. In a mouse UV-damage model, Combo evaluations demonstrated that rCol III contributed to restore transepidermal water loss (TEWL) values of UV-damaged skin to normal levels. Histological analysis further confirmed that rCol III substantially accelerated skin repair by enhancing collagen regeneration. Additionally, rCol III facilitated the regeneration of zebrafish tail fin tissue and alleviated shrinkage caused by excessive UV exposure. The biocompatible and bioactive rCol III offers a novel strategy for treating UV-induced skin damage, holding immense potential for applications in skin tissue engineering.

Although it has been established that polysaccharides have an effect on bone marrow haematopoiesis, it remains unclear how polysaccharides regulate bone marrow haematopoiesis during absorption and metabolism in vivo. In this study, the effect of a longan polysaccharide of large molecular weight (TLPL) on the gut microbiota of mice and its implications for the haematopoietic process in bone marrow was discussed. Here, the results show that after 21 days of TLPL consumption, the respective quantities of white blood cells, platelets, hemoglobin and bone marrow nucleated cells were determined to be 3.18 ± 1.71 (10⁹ L^-1), 1238.10 ± 164.41 (10⁹ L^-1), 135.10 ± 4.95 (g L^-1), and 1.70 × 10⁷, which reached 56.98%, 117.28%, and 47.74%, respectively, of the results for NC. TLPL both increased the thymus and spleen indexes by up to 2.08 ± 0.64 (mg g^-1) and 6.49 ± 2.45 (mg g^-1), respectively. Additionally, TLPL remodeled the gut microbiota with a significant increase in Lactobacillus in particular, and a significant increase in the level of the potential intestinal metabolite lactate was detected in the serum. Most importantly, a similarly significant up-regulation of the gene expression of the lactate receptor, Gpr81, in the myeloid cells was observed. These changes contributed to the activation of the secretion of various cytokines associated with haematopoiesis, with the levels of G-CSF, EPO, SCF and PF4 increased by 2.44 times, 1.14 times, 1.56 times and 1.13 times, respectively, compared to the MC group, which subsequently accelerated production of bone marrow cells and blood cells. The findings of this study reveal the unique mechanism of dried longan polysaccharides in ameliorating myelosuppression and provide a feasible strategy for the treatment of chemotherapy-induced myelosuppression with bioactive polysaccharides.

Tauopathies are neurodegenerative diseases that involve tau misfolding and aggregation in the brain. These diseases, including Alzheimer's disease (AD), are some of the least understood and most difficult to treat neurodegenerative disorders. Antibodies and antibody fragments that target tau oligomers, which are especially toxic forms of tau, are promising options for immunotherapies and diagnostic tools for tauopathies. In this study, we have developed conformational, tau oligomer-specific nanobodies, or single-domain antibodies. We demonstrate that these nanobodies, OT2.4 and OT2.6, are highly specific for tau oligomers relative to tau monomers and fibrils. We used epitope mapping to verify that these nanobodies bind to discontinuous epitopes on tau and to support the idea that they interact with a conformation present in the oligomeric, and not monomeric or fibrillar, forms of tau. We show that these nanobodies interact with tau oligomers in brain samples from AD patients and from healthy older adults with primary age-related tauopathy. Our results demonstrate the potential of these nanobodies as tau oligomer-specific binding reagents and future tauopathy therapeutics and diagnostics.

The Kirsanov reaction has been used to synthesise air stable, efficient and selective bifunctional aminophosphonium catalysts for the alternating ring-opening copolymerisation of cyclohexene oxide and phthalic anhydride without the need for a co-initiator.

We herein describe an alkylation reaction of indoles with NHC salts to access bis(indolyl)methanes as product. The NHC salt (or free NHC) serves as a C1 precursor due to decomposition of its N-heterocyclic ring. Although the exact roles of zinc powder and acetic/formic acid remain elusive, both of them are indispensable for this reaction. Two possible reaction pathways are proposed based on the results of mechanistic experiments.

Here, we report that black photothermal materials elevate solar heating temperatures across high solar absorption and low infrared radiation. Fe₃O₄ nanostructure films can be heated to 350 °C under light irradiation, and this system shows effective visible-light-driven ammonia synthesis production of 3677 μg g^-1 h^-1 under gas-solid phase catalysis without noble metals.