Ionic-complementary peptide matrix for enzyme immobilization and biomolecular sensing

Mechanism of Peptide Self-assembly and Its Study in Biomedicine

The development of peptide-based materials is one of the most challenging aspects of biomaterials research in recent years. The assembly of peptides is mainly controlled by forces such as hydrogen bonding, hydrophobic interaction, electrostatic interaction, and π-π accumulation. Peptides have unique advantages such as simple structure, easy synthesis, good biocompatibility, non-toxicity, easy modification, etc. These factors make peptides turn into ideal biomedical materials, and they have a broad application prospect in biomedical materials, and thus have received wide attention. In this review, the mechanism and classification of peptide self-assembly and its applications in biomedicine and hydrogels were introduced.

The use of engineered protein materials in electrochemical devices

Bioelectrochemical technologies have an important and growing role in healthcare, with applications in sensing and diagnostics, as well as the potential to be used as implantable power sources and be integrated with automated drug delivery systems. Challenges associated with enzyme-based electrodes include low current density and short functional lifetimes. Protein engineering is emerging as a powerful tool to overcome these issues. By taking advantage of the ability to precisely define protein sequences, electrodes can be organized into high performing structures, and enable the next generation of medical devices.

Peptide nanostructures in biomedical technology

Nanostructures of peptides have been investigated for biomedical applications due to their unique mechanical and electrical properties in addition to their excellent biocompatibility. Peptides may form fibrils, spheres and tubes in nanoscale depending on the formation conditions. These peptide nanostructures can be used in electrical, medical, dental, and environmental applications. Applications of these nanostructures include, but are not limited to, electronic devices, biosensing, medical imaging and diagnosis, drug delivery, tissue engineering and stem cell research. This review offers a discussion of basic synthesis methods, properties and application of these nanomaterials. The review concludes with recommendations and future directions for peptide nanostructures. WIREs Nanomed Nanobiotechnol 2016, 8:730-743. doi: 10.1002/wnan.1393 For further resources related to this article, please visit the WIREs website.

An ultrasensitive colorimetric aptasensor for ATP based on peptide/Au nanocomposites and hemin–G-quadruplex DNAzyme

A self-assembled peptide nanosphere was firstly applied to construct biosensors. A new signal amplification strategy was proposed for colorimetric aptasensor based on PNS/AuNPs composite. The colorimetric aptasensor displayed an ultra-high sensitivity for ATP detection with a LOD of 1.35 pM.

Dispersion of multiwalled carbon nanotubes in water using ionic-complementary peptides

We demonstrate the noncovalent modification of multiwalled carbon nanotubes (MWNTs) immersed in aqueous solution using the ionic-complementary peptide EFK16-II. This modification presumably arises through the interaction between the hydrophobic side of the EFK16-II and MWNT sidewalls and orients hydrophilic functional groups toward the solution phase and enables them to form highly stable dispersions in water. This stability can be attributed to the electrostatic repulsion between self-assembled peptides on the MWNTs. This repulsion as determined by ζ potential measurements increases as the pH diverges from the isoelectric point of ~6.7 for EFK16-II. This trend is confirmed by dynamic light scattering measurements of the suspensions showing a decrease in their particle size as the ζ potential increases. These EFK16-II-MWNT suspensions have been used to modify mica surfaces. Atomic force microscopy and scanning electron microscopy images show that this leads to a uniform distribution of individual modified MWNTs on the mica surfaces. Transmission electron microscopy reveals images of well-dispersed fibers with dimensions similar to those of individual MWNTs. Tissue culture plates previously contacted with EFK16-II-modified MWNTs have been shown to have enough biocompatibility for growth and attachment of cells. The biocompatibility and enhanced electrical conductivity that should result from the modification with these EFK16-II-MWNT suspensions opens up their use in a number of potential biomedical applications such as the design of bioelectrode interfaces and fabrication of biosensors with high sensitivity.

Glycine peptide bond formation catalyzed by faujasite

The catalysis of peptide bond formation between two glycine molecules on H-FAU zeolite was computationally studied by the M08-HX density functional. Two reaction pathways, the concerted and the stepwise mechanism, starting from three differently adsorbed reactants, amino-bound, carboxyl-bound, and hydroxyl-bound, are studied. Adsorption energies, activation energies, and reaction energies, as well as the corresponding intrinsic rate constants were calculated. A comparison of the computed energetics of the various reaction paths for glycine indicates that the catalyzed reaction proceeds preferentially via the concerted reaction mechanism of the hydroxyl-bound configuration. This involves an eight-membered ring of the transition structure instead of the four-membered ring of the others. The step from the amino-bound configuration to glycylglycine is the rate-determining step of the concerted mechanism. It has an estimated activation energy of 51.2 kcal mol(-1). Although the catalytic reaction can also occur via the stepwise reaction mechanism, this path is not favored.

Mechanical manipulation assisted self-assembly to achieve defect repair and guided epitaxial growth of individual peptide nanofilaments

We have succeeded in the production of defect-free and spatially organized individual one-dimensional peptide nanofilaments by real-time control of the self-assembly process on a solid substrate. Using a unique mechanical manipulation method based on atomic force microscopy, we are able to introduce mechanical stimuli to generate active ends at designated positions on an existing peptide nanofilament previously formed. By doing so, defects in the filament were removed, and self-repairing occurred when the active ends extended along the direction of the supporting lattice, resulting in the closure of the broken filament. Furthermore, new active ends of the nanofilaments can be specifically generated to guide the self-assembly of new filaments at designated positions with selected orientations. The mechanism of defect repair and guided epitaxial growth is also discussed.

Applications of peptide and protein-based materials in bionanotechnology

In this critical review we highlight recent advances in the use of peptide- and protein-related materials as smart building blocks in nanotechnology. Peptides and proteins can be very practical for new material synthesis and device fabrications. For example, peptides and proteins have superior specificity for target binding as seen in the antibody recognition and this biological recognition function can be used to assemble them into specific structures and shapes in large scale, as observed in the S-layer protein assembly. Collagens are assembled from triple helix peptides in micron-size with precise recognition between peptides and these biological assemblies can undergo smart structural change with pH, ionic strength, temperature, electric/magnetic fields. In addition, assemblies of peptides can template complex 3D crystallization processes with catalytic function, thus enabling to grow various materials in physiological conditions at low temperature in aqueous solution. The biomimetic growth of nanomaterials in aqueous solution is extremely useful when they are applied to therapeutics and medical imaging in vivo since these nanomaterials will be well dispersed in bodies. Peptides also play significant roles in signal transduction pathways in cells. For example, neuropeptides are used as neurotransmitters between synapses and these peptides bind receptors on the surface of cells to cascade the signal transduction. These versatile functions of peptides are extremely practical and here we discuss them with examples of relevant applications such as nanoreactors, sensors, electronics, and stimulus-responsive materials. It should be noted that peptide/protein assemblies can be applied to build up micron-scale materials that still feature excellent nano-scale ensembles, which essentially bridges the nano-world and the micro-world (86 references).