The influence of modified pluronic F127 copolymers with higher phase transition temperature on arsenic trioxide-releasing properties and toxicity in a subcutaneous model of rats.

Pluronic F127 (PF-127) shows thermoreversible property, which is of the utmost interest in optimizing drug formulation and delivery. However, its hitherto unresolved drawback of a low phase transition temperature (T (tr)) has limited its application in injectable drug delivery systems. We have recently synthesized a new type of PF-127 copolymers with higher T (tr) using a simple oxidative method. Here, we have investigated the drug-releasing feature of oxidized PF-127 and oxidized PF-127-containing silver nanoparticles (SNPs), carrying arsenic trioxide (ATO), in a subcutaneous model of rats. Injectable hydrogels prepared with oxidized PF-127s were less viscous and easier to inject, at the same concentration, than their precursor. Addition of SNPs further elevated T (tr), resulting in even lower viscosity of the injectable hydrogel prepared from SNP-containing oxidized PF-127. The oxidized PF-127 copolymers did not differ significantly in ATO-releasing ability, compared with parental PF-127, but the addition of SNPs altered the ATO-releasing feature of oxidized PF-127 to some extent. ATO-carrying oxidized PF-127s had similar toxicity, but the addition of SNPs enhanced the hepatotoxicity of ATO, as evidenced by elevated serum levels of alanine aminotransferase and aspartate aminotransferase and histological alterations, compared to parental PF-127. The results presented herein warrant further investigation of the modified PF-127 copolymers to deliver ATO or other drugs in the form of injectable hydrogels.

In-situ formed nanoscale Fe0 for fenton-like oxidation of thermosetting unsaturated polyester resin composites: Nondestructively recycle carbon fiber.

Thermosetting unsaturated polyester resin (UPR) composites were found widespread industrial applications. However, the numerous stable carbon-carbon bonds in cross-linked networks made them intractable for degradation, causing the large-scale composite wastes. Here a nanoscale Fe0 catalyst in-situ forming strategy was exploited to nondestructively recycle carbon fiber (CF) from UPR composites via Fenton-like reaction. The nano-Fe0 catalyst employed in this strategy activated H2O2 for removing UPR, featuring mild conditions and efficient degradation ability. Aiming at facile growth of the catalyst, a porous UPR was achieved by the hydrolysis of alkalic system. The nanoscale Fe0 catalyst was subsequently formed in-situ on the surface of hydrolyzed resin by borohydride reduction. Benefiting from fast mass transfer, the in-situ grown nano-Fe0 showed more efficient degradation ability than added nano-Fe0 or Fe2+ catalyst during Fenton-like reaction. The experiments indicated that hydrolyzed resin could be degraded more than 90% within 80 min, 80 °C. GC-MS, FT-IR analysis and Density functional theory (DFT) calculation were conducted to explained the fracture processes of carbon skeleton in hydrolyzed resin. Especially, a remarkable recovery process of CF from composites was observed, with a 100 percent elimination of resin. The recycled CF cloth exhibited a 99% strength retention and maintained the textile structure, microtopography, chemical structure, resulting in the nondestructive reclaim of CF. This in-situ formed nanoscale Fe0 catalytic degradation strategy may provide a promising practical application for nondestructively recycle CF from UPR composites.

A conductive polyacrylamide hydrogel enabled by dispersion-enhanced MXene@chitosan assembly for highly stretchable and sensitive wearable skin.

MXene is recognized as an ideal material for sensitive wearable strain sensors because of its unique advantages of conductivity, hydrophilicity and mechanical properties. However, conventional hydrogel sensors utilizing MXene as a conductive material inevitably encounter the excessive accumulation of MXene nanosheets during the process of synthesis, which limits the electron transmission, reduces the conductivity, and concurrently weakens the mechanical capability and sensitivity of sensors. Herein, we construct a dispersion-enhanced MXene hydrogel (DEMH) through a chitosan-induced self-assembly strategy for the first time. Charge transfer is carried out through the flow of a material or a collection of material microstructures, and thus the highly interconnected 3D MXene@Chitosan network provides fast transport channels for electrons, and the DEMH exhibits excellent conductivity and sensibility simultaneously. Besides, the electrostatic self-assembly between MXene and chitosan, and the supramolecular interactions between MXene, chitosan and polyacrylamide chain segment result in excellent mechanical strength (of up to 1900%) and flexibility of DEMH. Furthermore, the introduction of chitosan which possesses a high density of positively charged groups and MXene with semiconducting properties also endows sensor versatility, such as self-adhesion properties and antibacterial activity. This work develops a simple and cut-price strategy for combining MXene unaggregated into a hydrogel as a sensor with high conductivity, sensibility and flexibility. A simple and inexpensive strategy for avoiding self-stacking of two-dimensional conductive materials is proposed, which paves the way for a broad range of applications in electronic skin, human motion detection and intelligent devices.

Molecular and biotechnological advances in milk proteins in relation to human health.

Milk and colostrum is a rich source of proteins/peptides which have crucial roles in both neonates and adults. Milk bioactive proteins and peptides are potential health-enhancing nutraceuticals for food. Many bioactive peptides/proteins may be used as nutraceuticals, for example, in the treatment of cancer, asthma, diarrhea, hypertension, thrombosis, dental diseases, as well as mineral malabsorption, and immunodeficiency. The following components of milk are of particular interest in the recent years: 1) Lactoferrin [Lf] has antibacterial, antifungal, antiviral, antiparasite and antitumor activities and accelerates immunomodulatory properties. Lf is a potent inhibitor for several enveloped and naked viruses, such as rotavirus, enterovirus and adenovirus. Lf is resistant to tryptic digestion and breast-fed infants excrete high levels of faecal Lf, so that its effect on viruses replicating in the gastrointestinal tract is of great interest. 2) Casein has been protective in experimental bacteremia by eliciting myelopoiesis. Casein hydrolyzates were also protective in diabetic animals, reduced the tumor growth and diminished colicky symptoms in infants. 3) A Proline rich polypeptide [PRP] revealed variety of immunotropic functions, including promotion of T-cell activation and inhibition of autoimmune disorders such as multiple sclerosis. 4) alpha-Lactalbumin [LA] demonstrates antiviral, antitumor and anti-stress properties. 5) Lactoperoxidase shows antibacterial properties. 6) Lysozyme is effective in treatment of periodentitis and prevention of tooth decay. Taken together, milk-derived proteins and peptides are bio-available and safe for the prevention and treatment of various disorders in humans and may play a complementary [natural agents] rather than a substitutional role to the toxic synthetic pharmacological drugs.

Intravenous administration of arsenic trioxide encapsulated in liposomes inhibits the growth of C6 gliomas in rat brains.

Arsenic trioxide (ATO) is a potent anti-tumor agent used to treat acute promyelocytic leukemia (APL), and more recently solid tumors including gliomas. However, the dose of ATO required to suppress gliomas is markedly higher than that used to treat APL, which leads to toxicity and undesirable side-effects, even though the local concentration of ATO in brains is relatively low after systemic administration. In an attempt to minimize the toxicity, enhance the penetrating activity across the blood-brain barrier, and reduce enzyme degradation, we prepared ATO encapsulated in liposomes, and investigated its therapeutic effect on C6 gliomas established in rat brains. The prepared ATO liposomes were stable at room temperature for 3 days and the latency rate was over 90% within 72 h. Intravenous injection of ATO liposomes led to a much higher concentration of ATO (5- fold, compared with ATO solution) in rat brains, resulting in inhibition of C6 gliomas in brains and prolonging the survival of rats bearing brain gliomas. ATO-liposome therapy resulted in fewer side effects, compared with free ATO solution. ATO-liposome therapy inhibited tumor angiogenesis by downregulating the expression of vascular endothelial growth factor (VEGF), and inducing cell apoptosis. The results warrant future investigation of the use of ATO encapsulated in liposomes to treat gliomas.

Antiangiogenesis and damaging blood flow by antisense vascular endothelial growth factor oligodeoxynucleotides to suppress lung cancers.

Angiogenesis plays a key role in the growth and metastasis of lung cancers, and vascular endothelial growth factor (VEGF) is one of the major angiogenic factors. The study aims to investigate whether phosphoro thioate-modified antisense VEGF oligodeoxynucleo tides (ASODN) formulated in cationic liposome could inhibit the growth of Lewis lung carcinoma (LLC) tumors by antiangiogenesis. The study demonstrated that ASODN downregulated the expression of VEGF in LLC cells at levels of protein and mRNA in vitro and in vivo. The conditioned media obtained from LLC cells treated with ASODN significantly inhibited the proliferation of bovine aortic endothelial cells. The ASODN therapy significantly suppressed the growth of established subcutaneous LLC tumors in mice by inhibiting angiogenesis and damaging the blood flow of tumors. In conclusion, our results suggest that ASODN targeting VEGF presents a potent therapeutic strategy to combat lung cancers.