Electroaddressing of ZnS quantum dots by codeposition with chitosan to construct fluorescent and patterned device surface

In situ generation of silver nanoparticles and nanocomposite films based on electrodeposition of carboxylated chitosan

Herein, for the first time the electrodeposition of carboxylated chitosan is studied and utilized for the synthesis of silver nanoparticles (AgNPs) and generation of AgNPs/carboxylated chitosan nanocomposite films. Particularly, AgNPs are in situ synthesized on electrodes or substrates during the electrodeposition. Carboxylated chitosan not only acts as the green reducing agent and stabilizing agent for preparing AgNPs, but also serves as the main component in the electrodeposited nanocomposite film. The experimental results indicate that a smooth and homogeneous film is formed on the silver plate after electrodeposition, and the electrodeposited film can be detached from the silver plate as an independent film. The TEM observation and spectroscopic analysis results confirm the existence of AgNPs (the average size of 10 nm) in the nanocomposite film. The nanocomposite films with various shapes can be fabricated by the spatial selectivity of electrodeposition. In addition, the nanocomposite film containing AgNPs shows favorable antibacterial properties.

Connecting Biology to Electronics: Molecular Communication via Redox Modality

Biology and electronics are both expert at for accessing, analyzing, and responding to information. Biology uses ions, small molecules, and macromolecules to receive, analyze, store, and transmit information, whereas electronic devices receive input in the form of electromagnetic radiation, process the information using electrons, and then transmit output as electromagnetic waves. Generating the capabilities to connect biology-electronic modalities offers exciting opportunities to shape the future of biosensors, point-of-care medicine, and wearable/implantable devices. Redox reactions offer unique opportunities for bio-device communication that spans the molecular modalities of biology and electrical modality of devices. Here, an approach to search for redox information through an interactive electrochemical probing that is analogous to sonar is adopted. The capabilities of this approach to access global chemical information as well as information of specific redox-active chemical entities are illustrated using recent examples. An example of the use of synthetic biology to recognize external molecular information, process this information through intracellular signal transduction pathways, and generate output responses that can be detected by electrical modalities is also provided. Finally, exciting results in the use of redox reactions to actuate biology are provided to illustrate that synthetic biology offers the potential to guide biological response through electrical cues.

Review of Electrochemically Triggered Macromolecular Film Buildup Processes and Their Biomedical Applications

Macromolecular coatings play an important role in many technological areas, ranging from the car industry to biosensors. Among the different coating technologies, electrochemically triggered processes are extremely powerful because they allow in particular spatial confinement of the film buildup up to the micrometer scale on microelectrodes. Here, we review the latest advances in the field of electrochemically triggered macromolecular film buildup processes performed in aqueous solutions. All these processes will be discussed and related to their several applications such as corrosion prevention, biosensors, antimicrobial coatings, drug-release, barrier properties and cell encapsulation. Special emphasis will be put on applications in the rapidly growing field of biosensors. Using polymers or proteins, the electrochemical buildup of the films can result from a local change of macromolecules solubility, self-assembly of polyelectrolytes through electrostatic/ionic interactions or covalent cross-linking between different macromolecules. The assembly process can be in one step or performed step-by-step based on an electrical trigger affecting directly the interacting macromolecules or generating ionic species.

Electrodeposition of chitosan based on coordination with metal ions in situ-generated by electrochemical oxidation

Electrodeposition is an attractive technique that provides a controllable and programmable means to trigger the assembly of stimuli-responsive biopolymers (e.g., chitosan) for a diverse range of applications. Here, we report a new electrodeposition method for chitosan based on the coordination of chitosan to the metal ions in situ-generated by simultaneous electrochemical oxidation. In particular, we typically construct a deposited hydrogel on the copper electrode through this coordinated electrodeposition method, and the obtained hydrogel is smooth, transparent and homogeneous, as well as it has stability under acidic conditions and enough strength to be readily peeled from the electrode. This coordinated electrodeposition can be conveniently employed to build coatings (on the electrodes) or hydrogel films (peeled from the electrodes) with various shapes, and it also enables nanoparticles (e.g., fluorescent carbon dots) to be codeposited with chitosan. Furthermore, by enlisting the special benefits of the coordinated electrodeposition, the diverse hydrogel patterns can be constructed on the electrodes. Interestingly, this coordinated electrodeposition can be employed to directly build the complex hydrogel on the electrode to perform electrochemical detection. Therefore, it can be expected that this coordinated electrodeposition of chitosan has promising applications in biomedical devices, surface coating, and metallic biomaterials.

Electrodeposition of a carbon dots/chitosan composite produced by a simple in situ method and electrically controlled release of carbon dots

A carbon dots/chitosan composite that can be straightforwardly used for electrodeposition and controlled release was produced by a one-step microwave method.