Heavy reliance on petrochemical-based plastic foams in both industry and society has led to severe plastic pollution (the so-called "white pollution"). In this work, we develop a biodegradable, recyclable, and sustainable cellulose/bentonite (Cel/BT) foam material directly from resource-abundant natural materials (i.e.
View Article and Find Full Text PDFPM samples were collected from December 2017 to November 2018 at a northern suburb site of Nanjing. The concentrations of five amines, major water-soluble ions, organic carbon, and elemental carbon were determined. The five amines measured were methylamine, ethylamine, dimethylamine, trimethylamine, and aniline.
View Article and Find Full Text PDFHONO measurement was conducted using a wet-chemistry-based method at the Changzhou Environmental Monitoring Center in April 2017. HONO ranged from 0.2-13.
View Article and Find Full Text PDFA common bioelectronics goal is to enable communication between biology and electronics, and success is critically dependent on the communication modality. When a biorelevant modality aligns with instrumentation capabilities, remarkable successes have been observed (e.g.
View Article and Find Full Text PDFColloids Surf B Biointerfaces
September 2018
Antibodies are common recognition elements for molecular detection but often the signals generated by their stoichiometric binding must be amplified to enhance sensitivity. Here, we report that an electrode coated with a catechol-chitosan redox capacitor can amplify the electrochemical signal generated from an alkaline phosphatase (AP) linked immunoassay. Specifically, the AP product p-aminophenol (PAP) undergoes redox-cycling in the redox capacitor to generate amplified oxidation currents.
View Article and Find Full Text PDFThe growing importance of hydrogels in translational medicine has stimulated the development of top-down fabrication methods, yet often these methods lack the capabilities to generate the complex matrix architectures observed in biology. Here we show that temporally varying electrical signals can cue a self-assembling polysaccharide to controllably form a hydrogel with complex internal patterns. Evidence from theory and experiment indicate that internal structure emerges through a subtle interplay between the electrical current that triggers self-assembly and the electrical potential (or electric field) that recruits and appears to orient the polysaccharide chains at the growing gel front.
View Article and Find Full Text PDFACS Appl Mater Interfaces
August 2016
We report that information can be written into an erasable hydrogel medium by precisely imposing controlled electrical signals that trigger supramolecular self-assembly. We prepare the medium from a blend of two stimuli-responsive self-assembling polysaccharides agarose (thermally responsive) and chitosan (pH-responsive). Upon cooling the blend, agarose forms the hydrogel medium while the embedded chitosan chains can be induced to self-assemble in response to imposed pH cues.
View Article and Find Full Text PDFChlorogenic acid displays several important roles in the therapeutic properties of many herbs, such as antioxidant activity, antibacterial, antiviral, scavenging free radicals and exciting central nervous system. Only about one-third of chlorogenic acid was absorbed in its prototype, therefore, its gut metabolites play a more important role in the therapeutic properties of chlorogenic acid. It is necessary to consider not only the bioactivities of chlorogenic acid but also its gut metabolites.
View Article and Find Full Text PDFComplex structured soft matter may have important applications in the field of tissue engineering and biomedicine. However, the discovery of facile methods to exquisitely manipulate the structure of soft matter remains a challenge. In this report, a multilayer hydrogel is fabricated from the stimuli-responsive aminopolysaccharide chitosan by using spatially localized and temporally controlled sequences of electrical signals.
View Article and Find Full Text PDFACS Appl Mater Interfaces
February 2014
Polymeric systems that self-assemble through strong noncovalent bonds form structures that are highly dependent on the spatiotemporal sequence of cues that trigger self-assembly. Here, we prepared capsules with a semipermeable alginate-chitosan polyelectrolyte membrane that encapsulates a solution of the pH-responsive self-assembling aminopolysaccharide chitosan. Immersion of these capsules in a basic solution triggers gelation of the capsule contents, and the details of the gel-inducing treatment dramatically affect the final structure of the gelled compartment.
View Article and Find Full Text PDFMany applications in proteomics and lab-on-chip analysis require methods that guide proteins to assemble at surfaces with high spatial and temporal control. Electrical inputs are particularly convenient to control, and there has been considerable effort to discover simple and generic mechanisms that allow electrical inputs to trigger protein assembly on-demand. Here, we report the electroaddressing of a protein to a patterned surface by coupling two generic electroaddressing mechanisms.
View Article and Find Full Text PDFThere is considerable interest in creating convenient biosensing platforms that couple the capabilities of biology for selective detection with the power of electronics for signal transduction. Here, the capabilities of a polymeric fiber for facile biofunctionalization is coupled with the signal transduction capabilities of a conducting wire to generate a hybrid platform that can be viewed as either a biofunctionalized wire or a conducting fiber. Integral to this hybrid platform is the interface material chitosan that enables simple electrical signals to be employed to biofunctionalize conducting wires.
View Article and Find Full Text PDFWe report the assembly of seven different antibodies (and two antigens) into functional supramolecular structures that are specifically designed to facilitate integration into devices using entirely biologically based bottom-up fabrication. This is enabled by the creation of an engineered IgG-binding domain (HG3T) with an N-terminal hexahistidine tag that facilitates purification and a C-terminal enzyme-activatable pentatyrosine "pro-tag" that facilitates covalent coupling to the pH stimuli-responsive polysaccharide, chitosan. Because we confer pH-stimuli responsiveness to the IgG-binding domain, it can be electrodeposited or otherwise assembled into many configurations.
View Article and Find Full Text PDFThe ability to interface proteins to device surfaces is important for a range of applications. Here, we enlist the unique capabilities of enzymes and biologically derived polymers to assemble target proteins to electrode addresses. First, the stimuli-responsive aminopolysaccharide chitosan is directed to assemble at the electrode address in response to electrode-imposed signals.
View Article and Find Full Text PDFBiomacromolecules
May 2008
Fibers are a versatile platform because standard methods are available for the hierarchical assembly of individual fibers into controllable patterns (e.g., fabrics).
View Article and Find Full Text PDFAn alternative route to protein assembly at surfaces based on using the unique capabilities of biological materials for the spatially selective assembly of proteins is described. Specifically, the stimuli-responsive properties of aminopolysaccharide chitosan are combined with the molecular-recognition capabilities of biotin-streptavidin binding. Biotinylated chitosan retains its stimuli-responsive properties and is capable of electrodepositing at specific electrode addresses.
View Article and Find Full Text PDFJ Biomed Mater Res A
November 2007
Quaternized chitosan (QCS)/alginate (AL) nanoparticles (QCS/AL) were successfully prepared in neutral condition for the oral delivery of protein. The physicochemical structure of the QCS/AL nanoparticles was characterized by IR spectroscopy and transmission electron microscopy. The diameter of the nanoparticles with a positive surface charge was about 200 nm.
View Article and Find Full Text PDFThis study was designed to investigate the in vitro and in vivo transfection efficiency of chitosan nanoparticles used as vectors for gene therapy. Three types of chitosan nanoparticles [quaternized chitosan -60% trimethylated chitosan oligomer (TMCO-60%), C(43-45 KDa, 87%), and C(230 KDa, 90%)] were used to encapsulate plasmid DNA (pDNA) encoding green fluorescent protein (GFP) using the complex coacervation technique. The morphology, optimal chitosan-pDNA binding ratio and conditions for maximal in vitro transfection were studied.
View Article and Find Full Text PDFComplex beads composed of alginate and carboxymethyl chitin (CMCT) were prepared by dropping aqueous alginate-CMCT into an iron(III) solution. The structure and morphology of the beads were characterized by IR spectroscopy and scanning electron microscopy (SEM). IR confirmed electrostatic interactions between iron(III) and the carboxyl groups of alginate as well as CMCT, and the binding model was suggested as a three-dimensional structure.
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