Anti-Inflammatory and Tissue Adhesion Properties of an α-Linolenic Acid-Modified Gelatin-Based In Situ Hydrogel

Oxidized cellulose-filled double thermo/pH-sensitive hydrogel for local chemo-photothermal therapy in breast cancer

Lumpectomy plus radiation is a treatment option offering better survival than conventional mastectomy for patients with early-stage breast cancer. However, successive radioactive therapy remains tedious and unsafe with severe adverse reactions and secondary injury. Herein, a composite hydrogel with pH- and photothermal double-sensitive activity is developed via physical crosslinking. The composite hydrogel incorporated with tempo-oxidized cellulose nanofiber (TOCN), polyvinyl alcohol (PVA) and a polydopamine (PDA) coating for photothermal therapy (PTT) triggered in situ release of doxorubicin (DOX) drug was utilized to optimize postoperative strategies of malignant tumors inhibition. The incorporation of TOCN significantly affects the performance of composite hydrogels. The best-performing TOCN/PVA7 was selected for drug loading and polydopamine coating by rational design. In vitro studies have demonstrated that the composite hydrogel exhibited high NIR photothermal conversion efficiency, benign cytotoxicity to L929 cells, pH-dependent release profiles, and strong MCF-7 cell inhibitory effects. Then the TOCN/PVA7-PDA@DOX hydrogel is implanted into the tumor resection cavity for local in vivo chemo-photothermal synergistical therapy to ablate residue tumor tissues. Overall, this work suggests that such a chemo-photothermal hydrogel delivery system has great potential as a promising tool for the postsurgical management of breast cancer.

Engineering Yarrowia lipolytica to produce nutritional fatty acids: Current status and future perspectives

Due to their vital physiological functions, nutritional fatty acids have great potential as nutraceutical food supplements for preventing an array of diseases such as inflammation, depression, arthritis, osteoporosis, diabetes and cancer. Microbial biosynthesis of fatty acids follows the trend of sustainable development, as it enables green, environmentally friendly and efficient production. As a natural oleaginous yeast, Yarrowia lipolytica is especially well-suited for the production of fatty acids. Moreover, it has a variety of genetic engineering tools and novel metabolic engineering strategies that make it a robust workhorse for the production of an array of value-added products. In this review, we summarize recent advances in metabolic engineering strategies for accumulating nutritional fatty acids in Y. lipolytica, including conjugated fatty acids and polyunsaturated fatty acids. In addition, the future prospects of nutritional fatty acid production using the Y. lipolytica platform are discussed in light of the current progress, challenges, and trends in this field. Finally, guidelines for future studies are also emphasized.

Multifunctional chitosan/silver/tannic acid cryogels for hemostasis and wound healing

Wound dressing is a kind of significant artificial materials for protecting injured tissues and promoting wound healing. However, fabrication of antibacterial wound dressing usually involves tedious procedures and toxic components. Herein, we demonstrate a multifunctional chitosan/silver/tannic acid (CS/Ag/TA) cryogel based on an economic method to block acute hemorrhage and promote wound healing. The prepared CS/Ag/TA cryogel not only performs steady stability and compressibility, but also shows good antibacterial ability for both S. aureus and E. coli. Attributing to TA molecules, the CS/Ag/TA cryogel can effectively scavenge more than 95% of free radicals, showing effective oxidation resistance. Due to the porous structure and positive charge of CS, the prepared cryogel exhibits good hemostatic capability with a hemostasis time less than 20 s. Benefitting from the good biocompatibility and cell proliferation, the CS/Ag/TA cryogel can significantly promote wound repair in the skin incision model. All the results indicated that the greenly fabricated cryogel can be widely applied in clinic for hemostasis and wound healing.

Fish Gelatin-Based Absorbable Dural Sealant with Anti-inflammatory Properties

Cerebrospinal fluid (CSF) leakage from the dura mater during craniotomy is a common complication, which is associated with infection, meningitis, pneumocephalus, and delayed wound healing. In the present study, we developed an absorbable fish gelatin-based anti-inflammatory sealant for dura mater sealing to prevent CSF leakage. Gelatin derived from Alaska pollock (ApGltn) was modified with α-linolenic acid (ALA), an omega-3 fatty acid that exhibits anti-inflammatory properties, and cross-linked with a poly(ethylene glycol)-based cross-linker to develop ALA-ApGltn sealant (ALA-Seal). ALA-Seal demonstrated a higher storage modulus and tangent delta (tan δ) compared with those of the original ApGltn sealant (Org-Seal). The swelling ratio of ALA-Seal was markedly lower than that of DuraSeal, a commercially available dural sealant. Ex vivo burst strength measurements using porcine dura mater indicated that there was no significant difference between DuraSeal and ALA-Seal, despite ALA-Seal having an order of magnitude lower storage modulus. The anti-inflammatory properties of ALA-Seal, evaluated using brain microglial cells, were considerably higher than those of DuraSeal and Org-Seal, with a minimal adverse effect on cell viability. Therefore, compared to DuraSeal, ALA-Seal is a potential dural sealant with a lower swelling ratio, similar burst strength, and higher anti-inflammatory properties, which may prevent CSF leakage.