Guanidinylated bioactive chitosan-based injectable hydrogels with pro-angiogenic and mechanical properties for accelerated wound closure.

Wound healing is a complex process involving the concerted action of many genes and signaling pathways, with angiogenesis being crucial for expediting wound closure. Dressings that possess pro-angiogenic properties are increasingly recognized as attractive candidates for wound care. Drawing inspiration from the active closure of wounds in embryos, we have developed a thermo-responsive hydrogel with mechanoactive properties, combining vascular regeneration and skin wound contraction to accelerate healing. The significant improvement in vascular reconstruction is attributed to the synergistic effect of arginine and deferoxamine (DFO) released from the hydrogels. Additionally, the contraction force of the hydrogel actively promotes skin closure in wounds. Remarkably, groups treated with hydroxybutyl chitosan methacrylate combined with arginine (HBC_m_Arg/DFO) exhibited increased vascularization, and greater wound maturity, leading to enhanced healing. These results highlight the synergistic impact of pro-angiogenic and mechanical properties of the HBC_m_Arg/DFO hydrogel in accelerating wound healing in rats.

Minimally invasive surgery versus laparotomy of nonmetastatic pT4a colorectal cancer: a propensity score analysis.

AIM: The aim was to compare short-term and long-term oncological outcomes between minimally invasive surgery (MIS group) and laparotomy (lap group) in nonmetastatic pT4a colorectal cancer (CRC). MATERIALS AND METHODS: The study retrospectively analyzed the outcomes of 634 patients treated with radical operation from January 2015 to December 2021 for nonmetastatic pT4a CRC, with propensity score matching. RESULTS: The conversion rate from the MIS group to laparotomy is 3.5%. Intraoperative blood loss, time to first anal exhaust, defecation and drainage tube removal, and complication rate were significantly less in the MIS group. After 5 years, the outcomes of the MIS group were no inferior to laparotomy outcomes [overall survival (OS): 72.7 vs. 77.8%, P =0.285; disease-free survival (DFS): 72.2 vs. 75.0%, P =0.599]. And multivariate analysis showed that age greater than or equal to 60 years old, lymph node metastasis and the carcinoembryonic antigen levels were independent variables for OS, while lymph node metastasis and CA125 levels were independent variables for DFS. The results of the graph show the relationship between the sum of scores of sex, age, complications, BMI, carcinoembryonic antigen, age, CA125, tumor site, N stage and tumor length diameter and 1-year, 3-year, and 5-year mortality and DFS of patients. Among them, tumor length diameter and N stage are significantly correlated with long-term survival and disease-free of patients. CONCLUSION: MIS is safe and feasible for nonmetastatic pT4a CRC, with the added benefit of accelerated postoperative recovery. In oncology, MIS did not affect OS and DFS.

A Metal Ion and Thermal-Responsive Bilayer Hydrogel Actuator Achieved by the Asymmetric Osmotic Flow of Water between Two Layers under Stimuli.

Shape-morphing hydrogels have drawn great attention due to their wide applications as soft actuators, while asymmetric responsive shape-morphing behavior upon encountering external stimuli is fundamental for the development of hydrogel actuators. Therefore, in this work, bilayer hydrogels were prepared and the shrinkage ratios (LA/LN) of the AAm/AAc layer to the NIPAM layer immersed in different metal ion solutions, leading to bending in different directions, were investigated. The difference in the shrinkage ratio was attributed to the synergistic effect of the osmolarity difference between the inside and outside of the hydrogels and the interaction difference between the ion and hydrogel polymer chains. Additionally, under thermal stimuli, the hydrogel actuator would bend toward the NIPAM layer due to the shrinkage of the hydrogel networks caused by the hydrophilic-hydrophobic phase transition of NIPAM blocks above the LCST. This indicates that metal ion and thermal-responsive shape-morphing hydrogel actuators with good mechanical properties could be used as metal ion or temperature-controllable switches or other smart devices.

Recent Advances and Prospects of Small Molecular Organic Thermoelectric Materials.

Thermoelectric (TE) materials possess unique energy conversion capabilities between heat and electrical energy. Small organic semiconductors have aroused widespread attention for the fabrication of TE devices due to their advantages of low toxicity, large area, light weight, and easy fabrication. However, the low TE properties hinder their large-scale commercial application. Herein, the basic knowledge about TE materials, including parameters affecting the TE performance and the remaining challenges of the organic thermoelectric (OTE) materials, are initially summarized in detail. Second, the optimization strategies of power factor, including the selection and design of dopants and structural modification of the dope-host are introduced. Third, some achievements of p- and n-type small molecular OTE materials are highlighted to briefly provide their future developing trend; finally, insights on the future development of OTE materials are also provided in this study.

Injectable and Self-Healing Hydrogels with Double-Dynamic Bond Tunable Mechanical, Gel-Sol Transition and Drug Delivery Properties for Promoting Periodontium Regeneration in Periodontitis.

Injection of a hydrogel loaded with drugs with simultaneous anti-inflammatory and tissue regenerating properties can be an effective treatment for promoting periodontal regeneration in periodontitis. Nevertheless, the design and preparation of an injectable hydrogel with self-healing properties for tunable sustained drug release is still highly desired. In this work, polysaccharide-based hydrogels were formed by a dynamic cross-linked network of dynamic Schiff base bonds and dynamic coordination bonds. The hydrogels showed a quick gelation process, injectability, and excellent self-healing properties. In particular, the hydrogels formed by a double-dynamic network would undergo a gel-sol transition process without external stimuli. And the gel-sol transition time could be tuned by the double-dynamic network structure for in situ stimuli involving a change in its own molecular structure. Moreover, the drug delivery properties were also tunable owing to the gel-sol transition process. Sustained drug release characteristics, which were ascribed to a diffusion process, were observed during the first stage of drug release, and complete drug release owing to the gel-sol transition process was achieved. The sustained drug release time could be tuned according to the double-dynamic bonds in the hydrogel. The CCK-8 assay was used to evaluate the cytotoxicity, and the result showed no cytotoxicity, indicating that the injectable and self-healing hydrogels with double-dynamic bond tunable gel-sol transition could be safely used in controlled drug delivery for periodontal disease therapy. Finally, the promotion of periodontal regeneration in periodontitis in vivo was investigated using hydrogels loaded with ginsenoside Rg1 and amelogenin. Micro-CT and histological analyses indicated that the hydrogels were promising candidates for addressing the practical needs of a tunable drug delivery method for promoting periodontal regeneration in periodontitis.

A targeted nanocarrier based on polyspermine for the effective delivery of methotrexate in nasopharyngeal carcinoma.

Antitumor efficacy of methotrexate (MTX) is seriously limited due to its poor water solubility, nonspecific tumor distribution and low bioavailability. To overcome these obstacles, polyspermine (PSP) conjugated with MTX and folic acid (FA) as a novel targeted prodrug was designed and has been successfully synthesized using the amidation reaction. The strong hydrophilic properties of PSP made MTX well dispersed in water and the cellular uptake study indicated that the presence of FA enhanced uptake of the FA-PSP-MTX in folate receptor (FR) over-expressing human nasopharyngeal carcinoma HNE-1 cells. 1H NMR spectra and UV-Vis spectral analysis were carried out to confirm the MTX and FA content in FA-PSP-MTX, respectively. In CCK-8 assay and apoptosis analysis, the prodrug showed significantly enhanced anticancer efficacy than free MTX in HNE-1 cells. These results suggested that the prodrug has the potential for targeted delivery of MTX into cancer cells to improve its anti-tumor efficacy.

Modest Oxygen-Defective Amorphous Manganese-Based Nanoparticle Mullite with Superior Overall Electrocatalytic Performance for Oxygen Reduction Reaction.

Manganese-based oxides have exhibited high promise as noncoinage alternatives to Pt/C for catalyzing oxygen reduction reaction (ORR) in basic solution and a mix of Mn3+/4+ valence is believed to be vital in achieving optimum ORR performance. Here, it is proposed that, distinct from the most studied perovskites and spinels, Mn-based mullites with equivalent molar ratio of Mn3+ and Mn4+ provide a unique platform to maximize the role of Mn valence in facile ORR kinetics by introducing modest content of oxygen deficiency, which is also beneficial to enhanced catalytic activity. Accordingly, amorphous mullite SmMn2 O5-δ nanoparticles with finely tuned concentration of oxygen vacancies are synthesized via a versatile top-down approach and the modest oxygen-defective sample with an Mn3+ /Mn4+ ratio of 1.78, i.e., Mn valence of 3.36 gives rise to a superior overall ORR activity among the highest reported for the family of Mn-based oxides, comparable to that of Pt/C. Altogether, this study opens up great opportunities for mullite-based catalysts to be a cost-effective alternative to Pt/C in diverse electrochemical energy storage and conversion systems.

Local structure analysis around the Nd center in a ternary catalyst comprising Nd(vers)3, Al((i)Bu)3 and Al((i)Bu)2Cl by XAFS.

Lanthanide-based catalysts are highly active for isoprene polymerization in hexane. In this paper, a ternary catalyst consisting of neodymium neodecanoate {Nd(vers)3}, Al((i)Bu)3 and Al((i)Bu)2Cl was studied by using X-ray-absorption fine-structure (XAFS) technique. A sealed and moisture-proof liquid sample cell with adjustable thickness was designed for Nd LIII-edge XAFS measurements. Based on the XAFS data analysis, detailed structure changes around the Nd center were obtained. It was found that the Nd(vers)3 molecules formed an oligomer structure in hexane solution with two Nd-O subshells (5O @ 2.39 Å and 5O @ 2.54 Å) around the Nd center. The alkylation process by adding Al((i)Bu)3 to the hexane solution of Nd(vers)3 partially destroyed the aggregation degree of Nd(vers)3 molecules in hexane solution. Al((i)Bu)3 ligands were bonded to the Nd center by Nd-C bonding. With the Nd : Al ratio increasing from 1 : 2.5 to 1 : 10, the O neighbors around Nd decreased from 4 to 2 but with an unchanged Nd-O bond length of 2.38 Å, and the C neighbors around Nd were kept at ca. 4 with Nd-C bond lengths in the range of 2.57-2.58 Å. The Nd-O bonds can be further replaced by Nd-C bonds during the aging process. The chlorination process by adding Al((i)Bu)2Cl to the mixture solution of Nd(vers)3 and Al((i)Bu)3 restrained intensively the agglomeration of Nd(vers)3 molecules in hexane solution. Al((i)Bu)2Cl ligands were bonded to the Nd center by Nd-Cl bonds. There were about 3-4 C neighbors at 2.58 Å, 2 Cl neighbors at 2.87 Å, and 2 Al next-neighbors at 3.14 Å around the Nd center. After allowing the ternary catalyst to stand for 5 days, the coordination numbers of Nd-C and Nd-Cl were all stabilized to 3 without bond length changes, and partial single Cl(-) anions were also bonded to the Nd center. All these structural details and their change tendency demonstrate that the decrease of aggregation degree of Nd(vers)3 molecules in hexane solution can improve the catalytic activity of the ternary lanthanide-based catalyst system.

Synthesis of copolymers with cyclodextrin as pendants and its end group effect as superplasticizer.

In this paper, the efficient approach for the synthesis of ß-cyclodextrin (CD) based functional monomers was described. Based on the monovinyl ß-CD monomer (GMA-EDA-CD), a new type poly(AA-co-GMA-EDA-CD) (PCDs) copolymer bearing pendent CD groups was synthesized and used as superplasticizer. Their chemical compositions were characterized by FT-IR, NMR, MALDI-TOF and GPC. The effects of PCDs on dispersion and adsorption in cement mortars were detailed discussed. The results indicated that PCD copolymers behaved excellent dispersion ability and strong retarding effect. PCD2 with molar ratio (%) for monomer (AA:GMA-EDA-CD=80:20) had the best dispersion and dispersion maintaining abilities, which were mainly attributed to the synergistic effects of steric hindrance and electrostatic repulsive force, and the retarding effect of PCD copolymers resulted from steric hindrance repulsion of CD pendants and the large number of hydroxyl groups, which affected the hydration reaction of cement.