In situ fabrication of multifunctional gold-amino acid superstructures based on self-assembly

Bioinspired Amino Acid Based Materials in Bionanotechnology: From Minimalistic Building Blocks and Assembly Mechanism to Applications

Inspired by natural hierarchical self-assembly of proteins and peptides, amino acids, as the basic building units, have been shown to self-assemble to form highly ordered structures through supramolecular interactions. The fabrication of functional biomaterials comprised of extremely simple biomolecules has gained increasing interest due to the advantages of biocompatibility, easy functionalization, and structural modularity. In particular, amino acid based assemblies have shown attractive physical characteristics for various bionanotechnology applications. Herein, we propose a review paper to summarize the design strategies as well as research advances of amino acid based supramolecular assemblies as smart functional materials. We first briefly introduce bioinspired reductionist design strategies and assembly mechanism for amino acid based molecular assembly materials through noncovalent interactions in condensed states, including self-assembly, metal ion mediated coordination assembly, and coassembly. In the following part, we provide an overview of the properties and functions of amino acid based materials toward applications in nanotechnology and biomedicine. Finally, we give an overview of the remaining challenges and future perspectives on the fabrication of amino acid based supramolecular biomaterials with desired properties. We believe that this review will promote the prosperous development of innovative bioinspired functional materials formed by minimalistic building blocks.

Gold Nanoparticles Mineralized by Peptide Liquid Crystals with Dual-Functional Enzyme-like Activities: An Automatic Membrane Reactor for Glucose Detection

The development of stable multifunctional enzyme mimics with tandem catalytic effects provides a great opportunity to construct economical and convenient bioassays. Inspired by biomineralization, in this work self-assembled N-(9-fluorenylmethoxycarbonyl)-protected tripeptide (Fmoc-FWK-NH₂) liquid crystals were used as templates to in situ mineralize Au nanoparticles (AuNPs), and then a dual-functional enzyme-mimicking membrane reactor based on AuNPs and peptide-based hybrids was constructed. AuNPs with a uniform particle size and good dispersion were in situ reduced on the surface of the peptide liquid crystal due to the reduction of the indole group on the tryptophan residue, which exhibited excellent peroxidase-like and glucose oxidase-like activities simultaneously. Meanwhile, the oriented nanofibers aggregated into a three-dimensional network, which was further immobilized on the mixed cellulose membrane to form a membrane reactor. A biosensor was made to realize fast, low-cost, and automatic detection for glucose. This work represents a promising platform for the design and construction of novel multifunctional materials based on the biomineralization strategy.

Three-dimensional (3D) bioprinting of medium toughened dipeptide hydrogel scaffolds with Hofmeister effect

Short peptide self-assembled hydrogels as 3D bioprinting inks show excellent biocompatibility and diverse functional expansion, and have broad application prospects in cell culture and tissue engineering. However, the preparation of biological hydrogel inks with adjustable mechanical strength and controllable degradation for 3D bioprinting still faces big challenges. Herein, we develop dipeptide bio-inks that can be gelled in-situ based on Hofmeister sequence, and prepare hydrogel scaffold by using a layer-by-layer 3D printing strategy. Excitingly, after the introduction of Dulbecco's Modified Eagle's medium (DMEM), which is necessary for cell culture, the hydrogel scaffolds show an excellent toughening effect, which matches the needs of cell culture. It's notable that in the whole process of preparation and 3D printing of hydrogel scaffolds, no cross-linking agent, ultraviolet (UV), heating or other exogenous factors are involved, ensuring high biosafety and biocompatibility. After two weeks of 3D culture, millimeter-sized cell spheres are obtained. This work provides an opportunity for the development of short peptide hydrogel bioinks without exogenous factors in 3D printing, tissue engineering, tumor simulant reconstruction and other biomedical fields.

A Virus-like-inspired Nanoparticles Facilitates Bacterial Internalization for Enhanced Eradication of Drug-resistant Pathogen

The emergence and rapid spread of bacterial resistance pose an extremely serious threat to treat infections. Inspired that the spiny surface structure of virus plays an important role in mediating...

Self-Assembly of Ferrocene-Phenylalanine@Graphene Oxide Hybrid Hydrogels for Dopamine Detection

The effect of graphene oxide (GO) is explored on the self-assembly behavior of ferrocene-L-phenylalanine (Fc-F) in solution. The assembly behavior of Fc-F in GO dispersions at different concentrations and pH values was systematically investigated. At pH 8, a stable hybrid material could be formed by facile and elaborate supramolecular assembly. Moreover, the concentration of GO could also be used to adjust the mechanical strength of the hybrid hydrogel. Increasing the concentration of GO in the assembly process, a hydrogel with better mechanical strength could be obtained. The storage modulus could be up to 6.3 kPa by increasing the GO concentration to 1 mg/mL. Finally, the dopamine concentration in the solution could be detected in a high accuracy by loading the hybrid hydrogel onto the electrode surface. The R² of linear fitting equation could reach 0.9915 in the range of 10-200 μmol/L, indicating that it has the potential as biosensing electrode material.

Inverted Hydration Layers on Bio-Magnesium Surfaces in the Initial Degradation Stage and their Influence on Adsorption of Amino Acid Analogues: The Metadynamics Simulations

Deeply exploring the interaction of biomolecules with magnesium in solution is essential to understand the formation of complex bio-magnesium interfaces accompanied with corrosion products. Using the accelerated metadynamics simulations, we have investigated the interactions of amino acid analogues on clean and hydroxylated Mg(0001) surfaces by identifying their free energy barriers and adsorption sites. We find that there are two hydration layers stacked on the clean Mg(0001) surfaces and the hydroxylated Mg(0001) surfaces, which mainly determine the free energy barriers and adsorbed configurations. Further studies reveal that the water molecules in double hydration layers present two opposite orientations, depending on the charge distribution of the substrate. Specifically, oxygen atoms of water concentrate in the center of double hydration layers for a clean Mg surface but transfer to the outside surface once the Mg substrate is degraded. The reversed hydration layers greatly reduce the binding affinities of positively charged and electroneutral analogues. Overall, our simulation findings provide new insights into the interaction mechanism of biomolecules on a bio-magnesium device in the implantation initial stage, which is noteworthy for revealing the magnesium degradation mechanism in vivo.