Enzyme-responsive food packaging system based on pectin-coated poly (lactic acid) nanofiber films for controlled release of thymol.

Foodborne diseases caused by foodborne pathogens lead to serious harm to food safety and human health. This work fabricated an enzyme-responsive packaging film based on porous poly (lactic acid) (PLA) nanofibers modified by positively charged polyethyleneimine (PEI) and further to adsorb negatively charged pectin coating, which loaded with thymol (THY) for protecting fruits from microbial infection. The porous PLA nanofibers were fabricated by combining "Breath Figure" principle and electrospinning technique. The XPS and FTIR characterizations showed that PLA nanofiber membrane was successfully modified by PEI. The prepared nanofiber membrane significantly inhibited the growth of E. coli, S. aureus and Bacillus subtilis (＞95%), especially showed excellent antifungal activity against Aspergillus niger. The release of THY from pectin-coated porous nanofiber membrane (THY@PLA-PEI-Pectin) was triggered by pectinase, which was secreted by microorganisms from food contamination. Besides, the biocompatible THY@PLA-PEI-Pectin nanofiber membrane prolonged the shelf life of citrus. Therefore, this pectinase-responsive nanofiber membrane has desirable application prospects in the development of active or smart packaging systems.

An injectable and biodegradable nano-photothermal DNA hydrogel enhances penetration and efficacy of tumor therapy.

The biological barrier of solid tumors hinders deep penetration of nanomedicine, constraining anticancer treatment. Moreover, the inherent multidrug resistance (MDR) of cancer tissues may further limit the efficacy of anti-tumor nanomedicine. We synthesized highly permeable, photothermal, injectable, and positively charged biodegradable nucleic acid hydrogel (DNA-gel) nanoparticles to deliver cancer drugs. The nanoparticles are derived from photothermal materials containing black phosphorus quantum dots (BPQDs). The intra-tumoral BPQDs improve the sensitivity of tumor cells to photothermal therapy (PTT) and photodynamic treatment (PDT). Tumor cells take up the positively charged and controllable size DNA-gel nanoparticles, facilitating easy penetration and translocation of the particles across and within the cells. Mouse models demonstrated the anti-tumor activity of the DNA gel nanoparticles in vivo. In particular, the DNA gel nanoparticles enhanced clearance of both small and large tumor masses. Just 20 days after treatment, the tumor masses had been cleared. Compared to DOX chemotherapy alone, the DNA-gel treatment also significantly reduced drug resistance and improved the overall survival of mice with orthotopic breast tumors (83.3%, 78 d). Therefore, DNA gel nanoparticles are safe and efficient supplements for cancer therapy.

Biphasic synthesis of biodegradable urchin-like mesoporous organosilica nanoparticles for enhanced cellular internalization and precision cascaded therapy.

It is widely accepted that a small particle size and rough surface can enhance tumor tissue accumulation and tumor cellular uptake of nanoparticles, respectively. Herein, sub-50 nm urchin-inspired disulfide bond-bridged mesoporous organosilica nanoparticles (UMONs) featured with a spiky surface and glutathione (GSH)-responsive biodegradability were successfully synthesized by a facile one-pot biphasic synthesis strategy for enhanced cellular internalization and tumor accumulation. l-Arginine (LA) is encapsulated into the mesopores of UMONs, whose outer surface is capped with the gatekeeper of ultrasmall gold nanoparticles, i.e., UMONs-LA-Au. On the one hand, the mild acidity-activated uncapping of ultrasmall gold can realize a tumor microenvironment (TME)-responsive release of LA. On the other hand, the unique natural glucose oxidase (GOx)-mimicking catalytic activity of ultrasmall gold can catalyze the decomposition of intratumoral glucose to produce acidic hydrogen peroxide (H2O2) and gluconic acid. Remarkably, these products can not only further facilitate the release of LA, but also catalyze the LA-H2O2 reaction for an increased nitric oxide (NO) yield, which realizes synergistic catalysis-enhanced NO gas therapy for tumor eradication. The judiciously fabricated UMONs-LA-Au present a paradigm of TME-responsive nanoplatforms for both enhanced cellular uptake and tumor-specific precision cascaded therapy, which broadens the range of practical biomedical applications and holds a significant promise for the clinical translation of silica-based nanotheranostics.

Determination of haematological and biochemical parameters of Calf Saiga antelope (Saiga tatarica) living in the Gansu Endangered Animals Research Center.

BACKGROUND: The Saiga antelope (Saiga tatarica) is native to Eurasia and is a member of the family Bovidae. Prior to 1920, the antelope had been extensively hunted for its horns, which were used in traditional Chinese medicine. Since 1920, the Saiga antelope has been protected because of this extensive hunting, which nearly led to its extinction. OBJECTIVE: The study evaluated haematological and biochemical parameters to provide references for the Calf Saiga antelope (S. tatarica). The study also sought to explore the mechanisms affecting these parameters in both genders of the Calf Saiga antelope. METHODS: Haematological and biochemical parameters were collected from the Calf Saiga antelope. Haematological and biochemical parameters were analysed by the Coulter counter and Automatic analyser, respectively. RESULTS: The average concentrations of female triglyceride levels showed significantly higher values than the significant concentrations of male. Female red blood cells and platelets concentrations were statistically significant than the significant concentrations of males. Magnesium female concentrations were also significantly higher than male values. Other parameters showed differences between males and females. CONCLUSION: The reported results show that haematological and biochemical characteristics varied among Calf Saiga antelope and other animals. The study results suggest that regardless of the factors, breed, the breeding environment, and climatic variables, haematological and biochemical variations can be triggered that can result in a reduction in the heat production needed for maintenance of homeothermy.

A controllable local drug delivery system based on porous fibers for synergistic treatment of melanoma and promoting wound healing.

A dual function system that inhibits tumor growth while promoting wound healing is very necessary for melanoma treatment since tumor killing and skin healing are two complementary and influential processes. Herein, a controllable local drug delivery system based on porous fiber membranes incorporated with CuS nanoparticles is designed for chemo-photothermal synergistic melanoma therapy and promoting wound healing. The porous structure on the fiber surface significantly increases the drug loading capacity of the membrane and the photothermal effect of incorporated CuS nanoparticles is used to control the drug release rate. Benefitting from the chemo-photothermal synergistic therapy, the composite membrane can effectively kill melanoma cells in vitro and inhibit tumor growth in vivo. Furthermore, the membrane can also significantly promote the cutaneous wound healing by providing mechanical support and releasing copper ions. Thus, this work provides new ideas for the development of multifunctional local treatment and postoperative care systems.