Edaravone-loaded poly(amino acid) nanogel inhibits ferroptosis for neuroprotection in cerebral ischemia injury

Neurological injury caused by ischemic stroke is a major cause of permanent disability and death. The currently available neuroprotective drugs fail to achieve desired therapeutic efficacy mainly due to short circulation half-life and poor blood−brain barrier (BBB) permeability. For that, an edaravone-loaded pH/glutathione (pH/GSH) dual-responsive poly(amino acid) nanogel (NG/EDA) was developed to improve the neuroprotection of EDA. The nanogel was triggered by acidic and EDA-induced high-level GSH microenvironments, which enabled the selective and sustained release of EDA at the site of ischemic injury. NG/EDA exhibited a uniform sub-spherical morphology with a mean hydrodynamic diameter of 112.3 ± 8.2 nm. NG/EDA efficiently accumulated at the cerebral ischemic injury site of permanent middle cerebral artery occlusion (pMCAO) mice, showing an efficient BBB crossing feature. Notably, NG/EDA with 50 µM EDA significantly increased neuron survival (29.3%) following oxygen and glucose deprivation by inhibiting ferroptosis. In addition, administering NG/EDA for 7 d significantly reduced infarct volume to 22.2% ± 7.2% and decreased neurobehavioral scores from 9.0 ± 0.6 to 2.0 ± 0.8. Such a pH/GSH dual-responsive nanoplatform might provide a unique and promising modality for neuroprotection in ischemic stroke and other central nervous system diseases.

In vitro Degradation of Butanediamine-Grafted Poly(DL-Lactic acids)

The degradation of butanediamine-grafted poly（DL-lactic acid） polymers （BDPLAs） in vitro together with PDLLA and maleic anhydride-grafted poly（DL-lactic acid） polymers （MPLAs） was investigated by observation of the changes of the pH value of incubation media, and weight loss ratio during degradation duration of 12 weeks. The results reveal that the acidity of PDLLA degradation products was weakened or neutralized by grafting butanediamine onto PDLLA. A uniform degradation of BDPLAs was observed in comparison with an acidity-induced auto-accelerating degradation featured by PDLLA and MPLAs. The biodegradation behaviors of BDPLAs can be adjusted by controlling the content of BDA. BDPLAs might be a new derivative of PDLLA-based biodegradable materials for medical applications without acidity-caused irritations and acidity-induced auto-accelerating degradation behavior as that of PDLLA.

Synthesis of the Biomimetic Polymer: Aliphatic Diamine and RGDS Modified Poly(d,l-lactic acid)

A novel poly（d, /-lactic acid） （PDLLA） based biomimetic polymer was synthesized by grafting maleic anhydride, butanediamine and arg-gly-asp-ser （RGDS） peptides onto the backbone of PDLLA, aiming to overcome the acidity and auto-accelerating degradation of PDLLA during degradation and to improve its biospecificity and biocompatibility. The synthetic copolymer was characterized by FTIR, ^13C NMR and amino acid analyzer （AAA）.

Poly (Acrylamide-co-Acrylic Acid) Hydrogel Induced by Glow-Discharge Electrolysis Plasma and Its Adsorption Properties for Cationic Dyes

In this paper, poly （acrylamide-co-acrylic acid） （P（AM-co-AA）） hydrogel was pre- pared in an aqueous solution by using glow-discharge electrolysis plasma （GDEP） induced copoly- merization of acrylamide （AM） and acrylic acid （AA）, in which N,N＇-methylenebisacrylamide （MBA） was used as a crosslinker. A mechanism for the synthesis of P（AM-co-AA） hydrogel was proposed. To optimize the synthesis condition, the following parameters were examined in detail： the discharge voltage, discharge time, the content of the crosslinker, and the mass ratio of AM to AA. The results showed that the optimum pH range for cationic dyes removal was found to be 5.0-10.0. The P（AM-co-AA） hydrogel exhibits a very high adsorption potential and the ex- perimental adsorption capacities for Crystal violet （CV） and Methylene blue （MB） were 2974.3 mg/g and 2303.6 mg/g, respectively. The adsorption process follows a pseudo-second-order kinetic model. In addition, the adsorption mechanism of P（AM-co-AA） hydrogel for cationic dyes was also discussed.

Effects of Processing Variables on the Morphology and Diameter of Electrospun Poly(amino acid ester)phosphazene Nanofibers

Poly[（alanino ethyl ester）0.67 （glycino ethyl ester）0.33 phosphazene] （PAGP） was synthesized, and morphology and diameter of the electrospun PAGP nanofibers were systematically evaluated by using a cool field emission scanning electron microscope （SEM） with changing the important processing variables such as applied voltage, polymeric concentration, and ambient temperature. The average diameter of PAGP nanofibers was inversely proportional to the applied voltage, but increased with the increase of solution concentration. Lower environmental temperature was unfavorable due to the nanofibers conglutination.

Efficient and selective upcycling of waste polylactic acid into acetate using nickel selenide

The conversion of waste polylactic acid(PLA)plastics into high-value-added chemicals through electrochemical methods is a promising and sustainable approach.However,developing efficient and highly selective catalysts for lactic acid oxidation reaction(LAOR)and understanding the reaction process are challenging.Here,we report the electrooxidation of waste PLA to acetate at a high current density of 100 mA cm-2 with high Faraday efficiency(~95%)and excellent stability(>100 h)over a nickel selenide nanosheet catalyst.In addition,a total Faraday efficiency of up to 190%was achieved for carboxylic acids,including acetic acid and formic acid,by coupling with the cathodic CO_(2) reduction reaction.In situ experimental results and theoretical simulations revealed that the catalytic activity center of LAOR was dynamically formed NiOOH species,and the surface-adsorbed SeO_(x) species accelerated the formation of Ni~(3+)species,thus promoting catalytic activity.The mechanism of lactic acid electrooxidation was further elucidated.Lactic acid was dehydrogenated to produce pyruvate first and then formed CH_3CO due to preferential C-C bond cleavage,resulting in the presence of acetate.This work demonstrated a sustainable method for recycling waste PLA and CO_(2) into high-value-added products.

Branched chain amino acids alter fatty acid profile in colostrum of sows fed a high fat diet

Background:Branched chain amino acids(BCAAs)are important substrates for milk protein synthesis in the mammary gland,and are tightly related to lipid metabolism.No study has been performed examining the role of BCAAs with high fat diets on milk fat synthesis.This study was designed to investigate the effect of dietary BCAAs on growth performance of piglets,progeny body weight,and milk fat composition in sows fed a high fat diet.Four diets(CON=control diet;HF=high fat diet with 8%soybean oil;HF-MB=HF plus 0.39%BCAAs;HF-HB=HF plus 0.78%BCAAs)were fed to sows from late gestation to weaning.Results:Compared to HF,BCAAs(HF-MB and HF-HB)increased the litter weight(P<0.05)and overall litter weight gain(P<0.05)at weaning and increased colostrum fat content by 27.3–35.8%(P<0.01).Fatty acid profiles between the two doses of BCAAs were similar.Compared with HF,HF-MB tended to decrease the percentage of C18:3n3(P=0.063)and increased the percentage of C18:1n9c(P=0.03).In addition,BCAAs in HF-MB increased the concentration of total fatty acid by 22.1%in colostrum(P=0.03)but decreased that in serum at parturition by 53.2%(P=0.027).The fatty acids in colostrum that increased with BCAAs were C15:0,C17:0,C20:3n6,C20:4n6,C20:5n3 and C22:6n3(P=0.00~0.04).Colostrum fatty acids of C20:0,C21:0,C22:0,C16:1,C20:1,C18:1n9c also tended to be increased(0.05<P<0.1)with BCAAs.The change in sow serum fatty acid profile due to BCAAs was different from that in colostrum.Conclusions:BCAAs in high fat diet of sows altered the fatty acid composition in colostrum and enhanced litter growth.Our study indicated that BCAAs supplementation can enhance mammary fatty acid uptake and mammary fat synthesis and that supplemental BCAAs and fat in late gestation and lactation diets for sows can improve reproductive performance.

Study on the repairing effect of poly(N-vinylpyrrolidone-co-methacrylic acid)on permed or bleached damaged hair

The repairing effect of poly(N-vinylpyrrolidone-co-methacrylic acid)on permed or bleached damaged hair was studied.The combing and tensile strength of permed and bleached hair before and after treatment with the copolymer solution were tested,and the effects of the mass fraction of copolymer solution and immerseing time on the combing and tensile strength for permed or bleached damaged hair were investigated.The repair mechanism of permed or bleached damaged hair was also explored.The results show that when the immersing time is 3 hours,the tensile strength of the permed hair increases with the mass fraction of the copolymer solution Tensile strength within 0%-0.3%,but no obvious change is observed when250 Yield strength the mass fraction is over 0.3%.Therefore,the optimal mass 200 fraction of the copolymer solution for repairing the permed hair(cN/dtex)is 0.3%.Similarly,the optimal mass fraction of the copolymer 150strength/solution for repairing the bleached hair is 0.5%.Furthermore,the effects of immersing time on the tensile strength of the100Tensile damaged hair fibers were compared between the permed and90 bleached hair before and after treatment with the copolymer500.40.30.500.10.2 solution.Coincidentally,the optimal immersion time for permedw(P(NVP-co-MAA))/%or bleached damaged hair is both 2 hours.The tensile strength of the permed and bleached hair soaked in 0.3%and 0.5%copolymer solutions for 2 hours increases by 15.55%and 18.12%,respectively,compared to untreated hair.Through infrared spectroscopy analysis,it is found that the amide II band in hair fibers shifted to the blue after repair,with the wave number shift of 11.12 and 11.09 cm^(-1),which confirm the formation of hydrogen bonds in the hair samples.Additionally,the urea hydrogen bond disruption experiment demonstrates that urea does not disrupt the hydrogen bonds in untreated hair fibers,but prevents the formation of new hydrogen bonds in damaged hair fibers.It further validates that the improvement of the tensile strength of the copolymer treated damaged hair fibers is mainly due to the formation of hydrogen bonds.After treatment with the copolymer,the dry and wet combing friction decrease by 30.73%and 28.55%for the permed hair,and decrease by 28.55%and 24.83%for the bleached hairs,respectively.The scanning electron microscope shows that the copolymer can flatten the cuticle and fill the space between the raised cuticles.

Poly(amaranth) film based sensor for resolution of dopamine in the presence of uric acid:A voltammetric study

The electropolymerized film of amaranth was prepared on the surface of graphite pencil electrode（GPE） using cyclic voltammetric technique.This poly（amaranth） film coated electrode exhibited an excellent electrocatalytic activity towards the detection of dopamine（DA） in the presence of uric acid（UA） in 0.2 mol/L phosphate buffer solution at pH 7.0.The effect of interference study was carried out using differential pulse voltammetric technique.The poly（amaranth） modified GPE was applied for the detection of DA in dopamine injection with satisfactory results.

SYNTHESIS AND CHARACTERIZATION OF HYPERBRANCHED POLY(ESTER-AMIDE)S BASED ON GALLIC ACID AND DL-2-AMINOBUTYRIC ACID

A novel AB3-type monomer was prepared from gallic acid and DL-2-aminobutyric acid, and used for the synthesis of the biocompatible hyperbranched poly(ester-amide)s by self-polycondensation. The polymers were characterized via FTIR and NMR spectroscopy and thermal analysis, and the average degree of branching of the polymers was estimated to be 0.75. The polymers with abundant acetyl end groups were found to be amorphous with lower intrinsic viscosity, better thermal stability and excellent solubility.

Development of a Freeze-Dried Skin Care Product Composed of Hyaluronic Acid and Poly(γ-Glutamic Acid) Containing Bioactive Components for Application after Chemical Peels

Eight types of spongy sheet were prepared by freeze-drying aqueous solutions of hyaluronic acid (HA) and poly(γ-glutamic acid) (PGA) with or without bioactive components including vitamin C derivative (VC), glucosylceramide (GC), and epidermal growth factor (EGF). Spongy sheets were categorized into the following groups: Group I (HA/PGA), Group II (HA/PGA + VC), Group III (HA/PGA + GC), Group IV (HA/PGA + VC, GC), Group V (HA/PGA + EGF), Group VI (HA/PGA + VC, EGF), Group VII (HA/PGA + GC, EGF), and Group VIII (HA/PGA + VC, GC, EGF). In the first experiment, we examined fibroblast proliferation in conditioned medium that had been prepared by immersing each spongy sheet in a conventional culture medium. EGF-incorporating spongy sheets (Groups V-VIII) enhanced fibroblast proliferation more than EGF-free spongy sheets (Groups I-IV). In the second experiment, cytokine production by fibroblasts was evaluated using a wound surface model. This involved elevation of fibroblasts-incorporating collagen gel sheets to the air-liquid interface, on which a spongy sheet (Groups I, IV, V and VIII) was placed and cultured for 1 week. EGF-incorporating spongy sheets (Groups V and VIII) enhanced the production of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) by fibroblasts more than EGF-free spongy sheets (Groups I and IV). The effect of these four types of spongy sheet on wounds was investigated in animal experiments. Chemical peel was performed by contacting 50% trichloroacetic acid (TCA) on the dorsal region of mice, after which a spongy sheet was placed, and the wound condition was then observed in a two-week period. Angiogenesis was facilitated to a greater degree in Group VIII compared with Groups I, IV and V. This finding indicates that Group VIII spongy sheet is a promising aid for skin recovery after chemical peel.

Overoxidized poly(3,4-ethylenedioxythiophene)-gold nanoparticles-graphene-modified electrode for the simultaneous detection of dopamine and uric acid in the presence of ascorbic acid

An innovative,ternary nanocomposite composed of overoxidized poly(3,4-ethylenedioxythiophene)(OPEDOT),gold nanoparticles(Au NPs),and electrochemically reduced graphene oxide(ERGO)was prepared on a glassy carbon electrode(GCE)(OPEDOT-Au NPs-ERGO/GCE)through homogeneous chemical reactions and heterogeneous electrochemical methods.The morphology,composition,and structure of this nanocomposite were characterized by transmission electron microscopy,scanning electron microscopy,X-ray diffraction,and X-ray photoelectron spectroscopy.The electrochemical properties of the OPEDOT-Au NPs-ERGO/GCE were investigated by cyclic voltammetry using potassium ferricyanide and hexaammineruthenium(III)chloride redox probe systems.This modified electrode shows excellent electro-catalytic activity for dopamine(DA)and uric acid(UA)under physiological p H conditions,but inhibits the oxidation of ascorbic acid(AA).Linear voltammetric responses were obtained when DA concentrations of approximately 4.0-100μM and UA concentrations of approximately 20-100μM were used.The detection limits(S/N=3)for DA and UA were 1.0 and 5.0μM,respectively,under physiological conditions and in the presence of 1.0 m M of AA.This developed method was applied to the simultaneous detection of DA and UA in human urine,where satisfactory recoveries from 96.7%to 105.0%were observed.This work demonstrates that the developed OPEDOT-Au NPs-ERGO ternary nanocomposite,with its excellent ion-selectivity and electro-catalytic activity,is a promising candidate for the simultaneous detection of DA and UA in the presence of AA in physiological and pathological studies.

Synergism of Zinc Oxide/Organoclay-Loaded Poly(lactic acid) Hybrid Nanocomposite Plasticized by Triacetin for Sustainable Active Food Packaging

The synergistic effect of organoclay(OC)and zinc oxide(ZnO)nanoparticles on the crucial properties of poly(lactic acid)(PLA)nanocompositefilms was systematically investigated herein.After their incorporation into PLA via the solvent casting technique,the water vapor barrier property of the PLA/OC/ZnOfilm improved by a maximum of 86%compared to the neat PLAfilm without the deterioration of Young’s modulus or the tensile strength.Moreover,thefilm’s self-antibacterial activity against foodborne pathogens,including gram-negative(Escherichia coli,E.coli)and gram-positive(Staphylococcus aureus,S.aureus)bacteria,was enhanced by a max-imum of approximately 98–99%compared to the neat PLAfilm.Furthermore,SEM images revealed the homo-geneous dispersion of both nano-fillers in the PLA matrix.However,the thermal stability of thefilm decreased slightly after the addition of the OC and ZnO.Thefilm exhibited notable light barrier properties in the UV-Vis range.Moreover,the incorporation of a suitable biodegradable plasticizer significantly decreased the Tg and notably enhanced theflexibility of the nanocompositefilm by increasing the elongation at break approxi-mately 1.5-fold compared to that of the neat PLAfilm.This contributes to its feasibility as an active food packa-ging material.

Preparation and characterization of poly(amic acid)-stabilized silver nanoparticles

Stable and monodispersed silver nanoparticles were produced through a mild,convenient,one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer.The surface plasma band transition was monitored along with time in the reaction mixture for three sets of experiments by ultraviolet-visible spectroscopy.Analysis of the data with the Avrami equation yielded n exponent with values between 0.5 and 1.5,demonstrating three-dimensional heterogeneous nucleation and diffusion-controlled growth,accompanied by soft impingement effect.XRD and TEM analyses show a softly agglomerated polycrystalline state and a nearly spherical morphology (<50 nm) of nanoparticles.The FT-IR result indicates that the PAA molecular structure could be hardly influenced by the formation of nanoparticles.

Degradation mechanisms of poly (lactic-co-glycolic acid) films in vitro under static and dynamic environment

To understand their degradation mechanisms, PLGA (50:50) polymer films were prepared and eroded in the static and dynamic medium system. The degradation behavior was characterized through weight-average molecular weight change, mass loss, water uptake, etc. The results show that in dynamic system, significant mass loss begins until 10 d while mass loss does not begin until 30 d later, while weight-average molecular weight decreases observably at the beginning, and the appeasable mass loss happens in 20 d in static system, which suggests that the dynamic degradation rate is slower even than degradation in static medium. A mechanism was proposed that specimens in static medium take up water homogeneously and cause the polymer chains to degrade all over the specimen cross sections, which creates free carboxylic acid groups which lead to a decrease of pH value inside the swollen polymer and accelerate degradation of the polymer. While pH value inside polymer keeps constant in dynamic medium because of flowing of simulated medium, which make the hydrolytic cleavage of ester bonds inside specimen delayed.

The Inhibitive Effect of para-Amino Benzoic Acid and Its Polymer on Corrosion of Iron in 1 mol/L HC1 Solution

Poly p-aminobenzoic acid has been synthesized by chemical oxidation method. The inhibitive effect of poly p-aminobenzoic acid on iron in 1 mol/L HCI solution was investigated by polarization and electrochemical impedance spectroscopy and compared with that of monomer p-aminobenzoic acid. The effectiveness of poly p-aminobenzoic acid is very high in comparison with that of monomer. The results show that both cathodic and anodic processes were suppressed by p-aminobenzoic acid and poly p-aminobenzoic acid of iron dissolution in 1 mol/L HCI by their adsorption on the iron surface. The inhibition efficiency of both p-aminobenzoic acid and poly p-aminobenzoic acid were found to increase with the inhibitor concentrations. Ultraviolet （UV） reflectance studies of the iron surface after exposure to inhibitor acid show that poly p-aminobenzoic acid is strongly adsorbed on iron surface.

Synthesis and Properties of Lactic Acid-based Cross-linked Poly(ester-amide)

A novel lactic acid-based cross-linked poly（ester-amide） （LCPEA） was synthesized. The gel fraction of the LCPEA could be modulated by the reaction conditions and it affected the mechanical and thermal properties of the LCPEA. The tensile strength, elastic modulus and bend strength of the LCPEA of 65% gel fraction were 4.65, 136.55 and 39.63 MPa, respectively. The thermal decomposition temperature （50 wt%） of the LCPEA was around 410℃.

Preparation and Evaluation of Poly-γ-Glutamic Acid Hydrogel Mixtures with Basic Drugs or Acidic Drugs: Effect on Ease of Swallowing and Taste Masking

The purpose of this study was to prepare a poly-γ-glutamic acid hydrogel (PGA gel), to examine its ease of swallowing using texture profile analysis (TPA) and to evaluate its taste-masking effects on basic or acidic drugs using the artificial taste sensor. Using TPA, 0.5% and 1.0% PGA gels, 0.5% and 1.0% agar and 1.0% ι-carrageenan in the absence of drug was examined the hardness, adhesiveness and cohesiveness, ranked according to permission criteria published by the Japanese Consumers Affairs Agency. 0.5% PGA gel and 1.0% agar were classified into grade II. In the taste sensor measurement, the bitterness suppressions by 0.5% PGA gel were larger than that by 1.0% agar in all drugs and the bitterness suppressions of basic drugs in 0.5% PGA gel were more potent than those of acidic drugs in 0.5% PGA gel. 1H-nuclear magnetic resonance spectroscopic analysis was carried out to examine the difference in mechanism of bitterness suppression between basic drugs and acidic drugs mixed with PGA gel. The signals of the proton nearest to the nitrogen atom of basic drugs shifted clearly upfield, suggesting an interaction between the amino group of basic drugs and the carboxyl group of PGA gel. In conclusion, PGA gel is expected to be a useful excipient in formulations contained various drugs, especially basic drugs;it also has advantage for not only increasing ease of swallowing but also masking the bitterness of drugs even though a small amount of a single drug dose might be preferred.

Combretastatin A4/poly(L-glutamic acid)-graft-PEG conjugates self-assembled to nanoparticles

Combretastatin A4(CA4) possesses varying ability to cause vascular disruption in tumors,while the short half-life, low water solubility and deactivation of many CA4 analogs during storage limited its antitumor efficacy and drug stability. A novel macromolecular conjugate of CA4(CA4-PL) was synthesized by covalent bonding of CA4 onto poly(L-glutamic acid)-graft-polyethylene glycol(PLG-g-PEG) via Yamaguchi reaction. The obtained CA4-PL was characterized by ~1H NMR, GPC, and UV methods, and the properties of the nanoparticles composed of CA4-PL, including critical aggregation concentration, size and size distribution, and morphology, were investigated. CA4-PL can self-assemble to form micelle-like nanoparticles of 80～120 nm in diameter, which may have potential to improve the blood circulation period as well as the targetability of CA4, and find applications to treat various tumors when combined with traditional chemotherapy or radio therapy.

Preparation of Macroporous Poly (vinyl alcohol-co-triallyl isocyanurate) Beads Bearing Aminocarboxylic Acid as Functional Groups by Suspension Polymerization

Macroporous poly (vinyl acetate-co-triallyl isocyanurate) beads were prepared with suspension polymerization method. The copolymer beads were then transformed into poly (vinyl alcohol-co-triallyl isocyanurate) by ester exchange reaction. Aminocarboxylic acids were immobilized on the copolymer beads by the esterification of hydroxyl groups with diethyl-lenetriaminepentaacetic bisanhydride. The weak acid exchange capacities, specific surface areas and mean pore diameters of the resultant resin beads were measured.