Protein addressing on patterned microchip by coupling chitosan electrodeposition and ‘electro-click’ chemistry

Single/Multi-Network Conductive Hydrogels-A Review

Hydrogels made from conductive organic materials have gained significant interest in recent years due to their wide range of uses, such as electrical conductors, freezing resistors, biosensors, actuators, biomedical engineering materials, drug carrier, artificial organs, flexible electronics, battery solar cells, soft robotics, and self-healers. Nevertheless, the insufficient level of effectiveness in electroconductive hydrogels serves as a driving force for researchers to intensify their endeavors in this domain. This article provides a concise overview of the recent advancements in creating self-healing single- or multi-network (double or triple) conductive hydrogels (CHs) using a range of natural and synthetic polymers and monomers. We deliberated on the efficacy, benefits, and drawbacks of several conductive hydrogels. This paper emphasizes the use of natural polymers and innovative 3D printing CHs-based technology to create self-healing conductive gels for flexible electronics. In conclusion, advantages and disadvantages have been noted, and some potential opportunities for self-healing single- or multi-network hydrogels have been proposed.

Protein click chemistry and its potential for medical applications

A revolution in chemical biology occurred with the introduction of click chemistry. Click chemistry plays an important role in protein chemistry modifications, providing specific, sensitive, rapid, and easy-to-handle methods. Under physiological conditions, click chemistry often overlaps with bioorthogonal chemistry, defined as reactions that occur rapidly and selectively without interfering with biological processes. Click chemistry is used for the posttranslational modification of proteins based on covalent bond formations. With the contribution of click reactions, selective modification of proteins would be developed, representing an alternative to other technologies in preparing new proteins or enzymes for studying specific protein functions in different biological processes. Click-modified proteins have potential in diverse applications such as imaging, labeling, sensing, drug design, and enzyme technology. Due to the promising role of proteins in disease diagnosis and therapy, this review aims to highlight the growing applications of click strategies in protein chemistry over the last two decades, with a special emphasis on medicinal applications.

Selection of natural biomaterials for micro-tissue and organ-on-chip models

The desired organ in micro-tissue models of organ-on-a-chip (OoC) devices dictates the optimum biomaterials, divided into natural and synthetic biomaterials. They can resemble biological tissues' biological functions and architectures by constructing bioactivity of macromolecules, cells, nanoparticles, and other biological agents. The inclusion of such components in OoCs allows them having biological processes, such as basic biorecognition, enzymatic cleavage, and regulated drug release. In this report, we review natural-based biomaterials that are used in OoCs and their main characteristics. We address the preparation, modification, and characterization methods of natural-based biomaterials and summarize recent reports on their applications in the design and fabrication of micro-tissue models. This article will help bioengineers select the proper biomaterials based on developing new technologies to meet clinical expectations and improve patient outcomes fusing disease modeling.

Electro-deposition synthesis of tube-like collagen-chitosan hydrogels and their biological performance

Electro-deposition is a smart, safe and efficient method for biomaterial manufacturing. Collagen, a functional protein with excellent biocompatibility and biosafety, is a promising candidate for tissue engineering and biomedical applications. However, there are few reports on electro-deposition of biomaterials using collagen without electrically or magnetically active nanoparticles. In this study, electro-deposition was employed to swiftly fabricate tube-like collagen-chitosan hydrogels in a mild environment. Fourier transform infrared spectroscopy was employed to analyze the ingredients of the tube-like hydrogels. The result showed that the hydrogels contained both collagen and chitosan. The distribution and content of collagen in the hydrogels was further measured by hematoxylin-eosin staining and hydroxyproline titration. Collagen was distributed homogeneously and its content was related to the initial collagen:chitosan ratio. The tension resistance of the composite gels and the thermal stability of collagen in the composites were obviously enhanced by the chitosan doping. Meanwhile, the tube-like hydrogels retained a good ability to promote cell proliferation of collagen. This method offers a convenient approach to the design and fabrication of collagen-based materials, which could effectively retain the bioactivity and biosafety of collagen and furnish a new way to enhance the stability of collagen and the tensile strength of collagen-based materials.

Biofabricating a Silk Scaffold as a Functional Microbial Trap

Silk fibroin produced from silkworms has been intensively utilized as a scaffold material for a variety of biotechnological applications owing to its remarkable mechanical strength, extensibility, biocompatibility, and ease of biofunctionalization. In this research, we engineered silk as a novel trap platform capable of capturing microorganisms. Specifically, we first fabricated the silk material into a silk sponge by lyophilization, yielding a 3D scaffold with porous microstructures. The sponge stability in water was significantly improved by ethanol treatment with elevated β-sheet content and crystallinity of silk. Next, we biofunctionalized the silk sponge with a poly-specific microbial targeting molecule, ApoH (apolipoprotein H), to enable a novel silk-based microbial trap. The recombinant ApoH engineered with an additional penta-tyrosine was assembled onto the silk sponge through the horseradish peroxidase (HRP) mediated dityrosine cross-linking. Last, the ApoH-decorated silk sponge was demonstrated to be functional in capturing our model microorganism targets, E. coli and norovirus-like particles. We envision that this biofabricated silk platform, capable of trapping a variety of microbial entities, could serve as a versatile scaffold for rapid isolation and enrichment of microbial samples toward future diagnostics and therapeutics. This strategy, in turn, can expedite advancing future biodevices with functionality and sustainability.

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.

Conductive Polymer Composites from Renewable Resources: An Overview of Preparation, Properties, and Applications

This article reviews recent advances in conductive polymer composites from renewable resources, and introduces a number of potential applications for this material class. In order to overcome disadvantages such as poor mechanical properties of polymers from renewable resources, and give renewable polymer composites better electrical and thermal conductive properties, various filling contents and matrix polymers have been developed over the last decade. These natural or reusable filling contents, polymers, and their composites are expected to greatly reduce the tremendous pressure of industrial development on the natural environment while offering acceptable conductive properties. The unique characteristics, such as electrical/thermal conductivity, mechanical strength, biodegradability and recyclability of renewable conductive polymer composites has enabled them to be implemented in many novel and exciting applications including chemical sensors, light-emitting diode, batteries, fuel cells, heat exchangers, biosensors etc. In this article, the progress of conductive composites from natural or reusable filling contents and polymer matrices, including (1) natural polymers, such as starch and cellulose, (2) conductive filler, and (3) preparation approaches, are described, with an emphasis on potential applications of these bio-based conductive polymer composites. Moreover, several commonly-used and innovative methods for the preparation of conductive polymer composites are also introduced and compared systematically.

Click chemistry at the microscale

This manuscript reviews recent developments in click chemistry in microscale systems.

Considerations for hydrogel applications to neural bioelectronics

Hydrogels have garnered interest as materials in bioelectronics due to the capacity to tailor their properties. Appropriate selection and design of hydrogel systems for this application requires an understanding of the physical, chemical and biological properties as well as their structure–property relationships.

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.

Electrical Signal Guided Ibuprofen Release from Electrodeposited Chitosan Hydrogel

Electrical signal guided drug release from conductive surface provides a simple and straightforward way for advanced drug delivery. In this study, we investigated the ibuprofen release from electrodeposited chitosan hydrogel by applying electrical signals. Specifically, chitosan hydrogel was electrodeposited on titanium plate and used as a matrix for ibuprofen load and release. The release of ibuprofen from the chitosan hydrogel on titanium plate was pH sensitive. By applying a positive or negative electrical potential, the release rate of ibuprofen from the electrodeposited chitosan can be facilely controlled. Thus, coupling chitosan electrodeposition and electrical signal control spurs new possibilities for biopolymeric coating and drug elution on conductive implants.