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Abstract: A carboxylated superparamagnetic microbead-assisted sandwich fluoroimmunoassay was successfully demonstrated for the analysis of the early protein markers, myoglobin and human heart-type fatty acid-binding protein (H-FABP), associated with acute myocardial infarction. This assay approach consisted of the preparation of superparamagnetic polymer microbeads using a dispersion polymerization, followed by grafting of capture antibodies (monoclonal anti-H-FABP 10E1 and anti-myoglobin 7C3) onto the polymer microbeads using EDC-NHS protocol, and then a sequential sandwich fluoroimmunoassay using detection antibodies (FITC-labeled anti-H-FABP 9F3 and FITC-labeled anti-myoglobin 4E2). The Fe3O4 nanoparticles and carboxylated Fe3O4-polymer microbeads were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrophotometry, vibrating sample magnetometry, and X-ray diffraction. The fluoroimmunoassay images were recorded using a confocal laser-scanning microscope, and the average fluorescence intensity of the microbeads was found to correspond to the concentration of each cardiac marker, in agreement with the results obtained by a spectrofluorophotometer. The carboxylated magnetic microbead-assisted protocol could be utilized to semi-quantitatively detect both myoglobin and H-FABP. [Copyright &y& Elsevier]

Graphical abstract Lecithin doped poly(lactic acid)-thermoplastic polyurethane fibers were fabricated by electrospinning and their effect on hepatocyte viability was evaluated. Highlights • Poly(lactic acid)-thermoplastic polyurethane-lecithin fibers were prepared by electrospinning. • The introduction of lecithin improved the biocompatibility of the fibers. • The hepatocytes cultured on the fibers had higher viability than that on tissue culture plates. Abstract The development of hepatocyte cultures in vitro holds great significance in the study of bioartificial liver support systems. Electrospun fiber cultures have received widespread attention as an effective method to culture hepatocytes in vitro. Polylactic acid (PLA) –a synthetic polymer with high biocompatibility and biodegradability– is widely used to fabricate electrospun fibers in the biomedical field. However, the use of PLA is limited in cell cultures due to its brittleness, strong hydrophobicity, and lack of biologically active functional groups. In this study, thermoplastic polyurethane (TPU) and lecithin (Lec) were used to modify PLA by spiking them into the PLA electrospun solution in attempt to establish a suitable fiber scaffold for hepatocyte culture in bioreactors. TPU and lecithin incorporation into PLA increases the flexibility, hydrophilicity, and biologically active groups of the fibers which further promotes the growth, proliferation, and viability of hepatocytes. The morphology, wettability, and biocompatibility of the as-prepared PLA-TPU-Lec fibers were carefully characterized. The results showed that the PLA-TPU-Lec fibers possessed favorable morphology and hydrophilicity, as well as high biocompatibility ability. HepG2 cells on the PLA-TPU-Lec fibers and tissue culture plates (TCP) were exposed to hepatotoxins for 24 h and we found that HepG2 cells on the PLA-TPU-Lec fibers had higher viability than cells on TCP. The PLA-TPU-Lec fibers are therefore expected to be used in vitro for hepatocyte culture to improve cellular activity in artificial liver bioreactors. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Graphene oxide-catechol hybrid PLA (PLA-GO-DMA) nanofibers were prepared. • PLA-GO-DMA nanofiber mats exhibited excellent antibacterial abilities. • PLA-GO-DMA nanofiber mats exhibit favorable biocompatibility properties. Abstract The functionalization of electrospun mats with antimicrobial nanomaterials is an attractive strategy when developing functional graphene oxide coating materials to prevent bacterial colonization on surfaces. In this study, we demonstrated a simple approach to produce antimicrobial electrospun mats by dip-coating a polylactic acid (PLA) nanofiber into a graphene oxide-catechol derivative. PLA was first electrospun to yield narrow-diameter polymeric nanofibers. We then modified the graphene oxide (GO) with a catechol derivative – dopamine methacrylamide monomer (DMA) – to synthesize a GO-DMA nanocomposite material which exhibited robust antimicrobial properties. The catechol groups promote the immobilization of graphene oxide onto the PLA nanofibers and possess strong antimicrobial properties. We therefore selected this functional group to modify GO. We dipped the GO-DMA onto the PLA nanofiber to produce the final functionalized electrospun mats. The PLA mats which were functionalized using the GO-DMA nanocomposite (PLA-GO-DMA) displayed antibacterial activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. Furthermore, we studied the biocompatibility of the mats by culturing the cell lines (HepG2, A549, and HUVEC-C) of PLA-GO-DMA among the nanofibers which exhibited excellent biocompatibility. These results collectively demonstrate the potential of PLA-GO-DMA nanofiber mats as antimicrobial biomaterials and provide fundamental information toward the establishment of future biomedical applications. [ABSTRACT FROM AUTHOR]

Design and fabrication of scaffolds using appropriate biomaterials are a key step for the creation of functionally engineered tissues and their clinical applications. Poly(epsilon-caprolactone) (PCL), a biodegradable and biocompatible material with negligible cytotoxicity, is widely used to fabricate nanofiber scaffolds by electrospinning for the applications of pharmaceutical products and wound dressings. However, the use of PCL as such in tissue engineering is limited due to its poor bioregulatory activity, high hydrophobicity, lack of functional groups and neutral charge. With the attempt to found nanofiber scaffolds with antibacterial activity for skin tissue engineering, in this study, whey protein concentrate (WPC) was used to modify the PCL nanofibers by doping it in the PCL electrospun solution. By adding proteins into PCL nanofibers, the degradability of the fibers may be increased, and this further allows an antibiotic incorporated in the fibers to be efficiently released. The morphology, wettability and degradation of the as-prepared PCL/WPC nanofibers were carefully characterized. The results showed that the PCL/WPC nanofibers possessed good morphology and wettability, as well as high degradation ability to compare with the pristine PCL fibers. Afterwords, tetracycline hydrochloride as a model antibiotic drug was doped in the PCL/WPC nanofibers. In vitro drug release assays demonstrated that PCL/WPC nanofibers had higher antibiotic release capability than the PCL nanofibers. Also, antibacterial activity evaluation against various bacteria showed that the drug-doped PCL/WPC fibers possessed more efficient antibacterial activity than the PCL nanofibers. [ABSTRACT FROM AUTHOR]

A quaternized poly(dimethylaminoethyl methacrylate) functionalized graphene oxide (GO–QPDMAEMA) was successfully prepared in this study via click chemistry. Alkyne-functionalized graphene oxide (GO–alkyne) was first synthesized through a two-step amidation reaction of GO–COOH. Meanwhile, azide-terminated poly(dimethylaminoethyl methacrylate) (PDMAEMA–N 3 ) was prepared via the atom-transfer radical-polymerization of dimethylaminoethyl methacrylate (DMAEMA). Subsequently, PDMAEMA–N 3 was grafted onto the GO–alkyne through click chemistry to obtain PDMAEMA modified graphene oxide (GO–PDMAEMA). Finally, the tertiary amino groups of GO–PDMAEMA were quaternized by ethyl bromide to provide a quaternized poly(dimethylaminoethyl methacrylate) functionalized graphene oxide (GO–QPDMAEMA). Various characterization techniques, including Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV–vis spectrometry, ζ potential, Raman, contact angle analyses and field emission scanning electron microscope were used to ascertain the successful preparation of the quaternized GO–QPDMAEMA. Furthermore, antibacterial and antifouling activities of GO–QPDMAEMA were investigated via protein adsorption, as well as bacterial and cell adhesion studies. The results suggest that the GO–QPDMAEMA surface exhibited significant antibacterial and antifouling properties, compared with the GO–COOH and GO–PDMAEMA surfaces. [ABSTRACT FROM AUTHOR]

Abstract: With the development of polymer-based biomaterials, aliphatic polyesters have attracted considerable interest because of their non-toxicity, non-allergenic property, and good biocompatibility. However, the hydrophobic nature and the lack of side chain functionalities of aliphatic polyesters limit their biomedical applications. In this study, we prepared four new polyesters: poly(sulfobetaine methacrylate)-, poly(2-methacryloyloxyethyl phosphotidylcholine)-, poly(ethylene glycol)-, and quaternized poly[(2-dimethylamino)ethyl methacrylate]-grafted poly(propargyl glycolide)-co-poly(ɛ-caprolactone). Their synthesis was conducted through ring-opening polymerization of acetylene-functionalized lactones and subsequent graft of bioactive units using click chemistry. The chemical structures of the polyesters were characterized through nuclear magnetic resonance and Fourier-transform infrared spectroscopy, and their physical properties (including molecular weight, glass transition temperature, and melting point) were determined using gel permeation chromatography and differential scanning calorimetry. For studies on their hydrophilicity, stability, and anti-bioadhesive property, a series of polymeric surfaces of these polyesters was prepared by coating them onto glass substrates. The hydrophilicity and stability of these polyester surfaces were examined by contact angle measurements and attenuated total reflection Fourier-transform infrared spectroscopy. Their anti-bioadhesive property was investigated through protein adsorption, as well as cellular and bacterial adhesion assays. The prepared polyesters showed good hydrophilicity and long-lasting stability, as well as significant anti-fouling property. The newly prepared polyesters could be developed as promising anti-fouling materials with extensive biomedical applications. [Copyright &y& Elsevier]

Abstract: A new antifouling polyester monomethoxy-poly(ethylene glycol)-b-poly(l-lactide)-b-poly(sulfobetaine methacrylate) (MPEG-PLA-PSBMA) was obtained by ring-opening polymerization of l-lactide, and subsequent click chemistry to graft the azide end-functionalized poly(sulfobetaine methacrylate) (polySBMA) moieties onto the alkyne end-functionalized MPEG-PLA (MPEG-PLA-alkyne). The chemical structure of the polymer was characterized using 1H nuclear magnetic resonance and Fourier-transform infrared spectroscopy, and its physical properties (including molecular weight, glass transition temperature, and melting point) were determined using gel permeation chromatography and differential scanning calorimetry. To investigate its hydrophilicity and stability, as well as its antifouling properties, the polymer was also prepared as a surface coating on glass substrates. The wettability and stability of this polyester was examined by contact angle measurements. Furthermore, its antifouling properties were investigated via protein adsorption, cell adhesion studies, and bacterial attachment assays. The results suggest that the prepared zwitterionic polyester exhibits durable wettability and stability, as well as significant antifouling properties. The new zwitterionic polyester MPEG-PLA-PSBMA could be developed as a promising antifouling material with extensive biomedical applications. [Copyright &y& Elsevier]

Abstract: Thrombus formation and microbial invasion are two major complications that impede the widespread application of blood-contacting devices. The development of new materials that have blood compatibility and antibacterial adhesion activity has gained increased attention. In this study, a new class of polymers composed of hydrophilic dendronized polyethylene glycol (PEG) methacrylate and hydrophobic octyne monomethyl ether-glycidyl methacrylate was synthesized via click chemistry and free radical polymerization. Different polymers were synthesized by changing the ratio of the two monomers. The structures of the synthesized polymers were characterized by 1H nuclear magnetic resonance and Fourier-transform infrared spectroscopy. Their physical properties such as molecular weight, polydispersity, and glass transition temperature were determined using gel permeation chromatography and differential scanning calorimetry. The synthesized polymers were coated on glass slides to prepare a series of polymeric surfaces. Contact angle measurements and attenuated total reflection Fourier-transform infrared spectroscopy analysis showed that the polymeric surfaces had long-lasting stability. The introduction of the monomer dendronized PEG methacrylate to the polymers greatly improved the hydrophilicity of the polymeric surfaces. The blood compatibility of the synthesized polymers was evaluated by protein (bovine serum albumin and fibrinogen) adsorption and platelet adhesion assays. Their antibacterial adhesion ability was investigated using the Gram-negative Pseudomonas aeruginosa and the Gram-positive Staphylococcus aureus. The results demonstrated that the amount of adsorbed protein, platelets, and bacteria on the polymeric surfaces decreased with increased content of the hydrophilic monomer dendronized PEG methacrylate in the polymers. However, no obvious difference was observed when such content exceeded 50mol%. The results suggested that the new kind of polymer could be developed as a promising blood-contact coating material that may have extensive medical applications. [Copyright &y& Elsevier]

Abstract: The current paper reports the synthesis of a highly hydrophilic, antifouling dendronized poly(3,4,5-tris(2-(2-(2-hydroxylethoxy)ethoxy)ethoxy)benzyl methacrylate) (PolyPEG) brush using surface initiated atom transfer radical polymerization (SI-ATRP) on PDMS substrates. The PDMS substrates were first oxidized in H2SO4/H2O2 solution to transform the Si–CH3 groups on their surfaces into Si–OH groups. Subsequently, a surface initiator for ATRP was immobilized onto the PDMS surface, and PolyPEG was finally grafted onto the PDMS surface via copper-mediated ATRP. Various characterization techniques, including contact angle measurements, attenuated total reflection infrared spectroscopy, and X-ray photoelectron spectroscopy, were used to ascertain the successful grafting of the PolyPEG brush onto the PDMS surface. Furthermore, the wettability and stability of the PDMS–PolyPEG surface were examined by contact angle measurements. Anti-adhesion properties were investigated via protein adsorption, as well as bacterial and cell adhesion studies. The results suggest that the PDMS–PolyPEG surface exhibited durable wettability and stability, as well as significantly anti-adhesion properties, compared with native PDMS surfaces. Additionally, our results present possible uses for the PDMS–PolyPEG surface as adhesion barriers and anti-fouling or functional surfaces in biomedical applications. [Copyright &y& Elsevier]

Abstract: Rice-like polymeric nanoparticles (NPs) composed of a new redox-responsive polymer, poly(ethylene glycol)-b-poly(lactic acid) (MPEG-SS-PLA), were prepared to carry paclitaxel (PTX) for glutathione (GSH)-regulated drug delivery. The PTX-loaded MPEG-SS-PLA NPs were fabricated using an optimized oil-in-water emulsion/solvent evaporation method. The size and morphology of the prepared NPs were characterized by scanning electron microscopy (SEM). The SEM results demonstrate that the NPs were dispersed as individual particles and were rice-shaped. The PTX loading efficiency, in vitro release, and stability of the NPs were analyzed by high-performance liquid chromatography (HPLC). The HPLC results revealed that the NPs released almost 90% PTX within 96h when GSH presented at intracellular concentrations, whereas only a very small PTX amount was released at plasma GSH levels. The in vitro cytotoxicities of the NPs against A549, MCF-7, and HeLa carcinoma cells were assessed using a standard methyl thiazolyl tetrazoliun (MTT) assay. The MTT assay results show that the NPs caused concentration- and time-dependent changes in cell viability. To investigate the cellular uptake of the PTX-loaded NPs, visual endocytosis assay was performed using the fluorescent dye coumarin-6 as a model drug. The endocytosis assay results reveal rapid penetration and intracellular accumulation of coumarin-6-loaded NPs, as well as rapid coumarin-6 dispersion from the NPs. Overall, these findings establish that the NPs containing the synthesized redox-responsive polymer MPEG-SS-PLA can be used as potential carrier systems for antitumor drug delivery. [Copyright &y& Elsevier]

Abstract: Locoweeds cause significant livestock poisoning and economic loss all over the world. The purpose of this study was to investigate the immune effects of locoweed toxin, swainsonine (SW) and human serum albumin (HSA) conjugate (SW–HSA), on goats. Twenty-four Sannon goats were randomly separated into immune control group (eight goats), immune poisoning group I (six goats), immune poisoning group II (six goats) and poisoning control group (four goats). Immune control group, immune poisoning groups I and II were first vaccinated with SW–HSA conjugate. The poisoning control group, immune poisoning groups I and II were then fed with 10.0g/kgBW/day dry powder of Oxytropis kansuensis Bunge everyday morning. The immune control group was supplied with an alfalfa-based diet. Blood samples of these experimental animals were collected at different time interval. Immunoassay was performed using indirect ELISA and E-rosette technique. The results show that, after second booster immunization: (1) anti-SW antibody level in some goats increased to 28, which proves that SW–HSA conjugate can induce experimental animals to produce high-level anti-SW antibody in their bodies; (2) the high-level antibody in their bodies could maintain 30 days, and decreased gradually after poisoning experiment (in our experiment, there was a return of the antibody level on day 21 after poisoning experiment); (3) the decreasing of the E-rosette rate of the immune poisoning group was delayed 14 days, which suggests that SW–HSA could low down the loss of the immunity of the goats; (4) swainsonine concentration in the blood was significantly lower (p <0.01) in the immune poisoning groups than that in the poisoning control group, and there was no significant difference (p >0.01) between the two immune poisoning groups within the poisoning experiment. [Copyright &y& Elsevier]

• PLA and Au@PDA NPs blend electrospinning to produce PLA-Au@PDA nanofibers. • In situ assembly of well-dispersed Ag nanoparticles to produce PLA-Au@PDA@Ag nanofibers. • PLA-Au@PDA@Ag nanofibers exhibited good hydrophilicity and excellent antibacterial abilities. Nanofibrous membranes which exhibit bacteriostatic functions are a good strategy to prevent microorganisms from adhering to the surface of biomaterials. Here, we report the synthesis of such a nanofibrous membrane which can be applied to biological coatings to reduce bacteriostatic functionality. Ascorbic acid was utilized to reduced chloroauric acid to gold nanoparticles (AuNPs). Dopamine was then polymerized upon AuNP surfaces by ultrasound-assistance, to synthesize core-shell structured polydopamine-coated AuNPs (Au@PDA NPs). The Au@PDA NPs were then mixed with polylactic acid (PLA) for electrospinning into cylindrical nanofibers (136.6 nm diameter). PLA-Au@PDA nanofibrous membranes were finally immersed in silver nitrate for in situ reduction into a silver nanoparticle (AgNP) coating to yield PLA-Au@PDA@Ag nanofibers. The PLA-Au@PDA@Ag nanofibers were characterized based on field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and contact angle analyses. The antibacterial properties of the PLA-Au@PDA@Ag nanofibers were examined based on the optical density absorbance of bacterial cell suspensions, traditional colony plate counts, zone inhibition analyses, and field-emission scanning electron microscopy. Escherichia coli and Staphylococcus aureaus respectively served as Gram negative and positive bacterial models of industrial relevance. The data conclusively illustrates the antimicrobial and biomedical applications of PLA-Au@PDA@Ag nanofibers. [ABSTRACT FROM AUTHOR]