adhesin-derived peptide mediates strong pull-off forces in aqueous high-ionic-strength environments.

In this letter, the pull-off forces of adsorbed films of four Bap1-inspired peptides in various solvents were investigated on negatively charged mica substrates using the surface forces apparatus (SFA), complemented with dynamic light scattering (DLS) for characterizing the aggregation behavior of peptides in solution. Bap1-inspired peptides consisted of the 57 amino acid wild-type sequence (WT); a scrambled version of the WT used to investigate the impact of the primary amino acid sequence in pull-off forces (Scr); a ten amino acid sequence rich in hydrophobic content (CP) of the WT sequence, and an eight amino acid sequence (Sh1) that corresponds to the pseudo-repeating sequence in the 57 AA. SFA results showed remarkable pull-off forces for CP, particularly in the presence of salts: measured pull-off forces were 26.

Coiled Coil Peptide Tiles (CCPTs): Expanding the Peptide Building Block Design with Multivalent Peptide Macrocycles.

Owing to their synthetic accessibility and protein-mimetic features, peptides represent an attractive biomolecular building block for the fabrication of artificial biomimetic materials with emergent properties and functions. Here, we expand the peptide building block design space through unveiling the design, synthesis, and characterization of novel, multivalent peptide macrocycles (96mers), termed coiled coil peptide tiles (CCPTs). CCPTs comprise multiple orthogonal coiled coil peptide domains that are separated by flexible linkers.

Interhelical E@g-N@a interactions modulate coiled coil stability within a de novo set of orthogonal peptide heterodimers.

The designability of orthogonal coiled coil (CC) dimers, which draw on well-established design rules, plays a pivotal role in fueling the development of CCs as synthetically versatile assembly-directing motifs for the fabrication of bionanomaterials. Here, we aim to expand the synthetic CC toolkit through establishing a "minimalistic" set of orthogonal, de novo CC peptides that comprise 3.5 heptads in length and a single buried Asn to prescribe dimer formation.

Shape-Shifting Peptide Nanomaterials: Surface Asymmetry Enables pH-Dependent Formation and Interconversion of Collagen Tubes and Sheets.

The fabrication of dynamic, transformable biomaterials that respond to environmental cues represents a significant step forward in the development of synthetic materials that rival their highly functional, natural counterparts. Here, we describe the design and synthesis of crystalline supramolecular architectures from charge-complementary heteromeric pairs of collagen-mimetic peptides (CMPs). Under appropriate conditions, CMP pairs spontaneously assemble into either 1D ultraporous (pore diameter >100 nm) tubes or 2D bilayer nanosheets due to the structural asymmetry that arises from heteromeric self-association.

Seeded Heteroepitaxial Growth of Crystallizable Collagen Triple Helices: Engineering Multifunctional Two-Dimensional Core-Shell Nanostructures.

Engineering free-standing 2D nanomaterials with compositional, spatial, and functional control across size regimes from the nano- to mesoscale represents a significant challenge. Herein, we demonstrate a straightforward strategy for the thermodynamically controlled fabrication of multicomponent sectored nanosheets in which each sector can be chemically and spatially addressed independently and orthogonally. Collagen triple helices, comprising collagen-mimetic peptides (CMPs), are employed as molecularly programmable crystallizable units.

2D Crystal Engineering of Nanosheets Assembled from Helical Peptide Building Blocks.

The successful integration of 2D nanomaterials into functional devices hinges on developing fabrication methods that afford hierarchical control across length scales of the entire assembly. We demonstrate structural control over a class of crystalline 2D nanosheets assembled from collagen triple helices. By lengthening the triple helix unit through sequential additions of Pro-Hyp-Gly triads, we achieved sub-angstrom tuning over the 2D lattice.

Triblock peptide-oligonucleotide chimeras (POCs): programmable biomolecules for the assembly of morphologically tunable and responsive hybrid materials.

Triblock peptide-oligonucleotide chimeras (POCs) consisting of peptides and oligonucleotides interlinked by an organic core are presented and their assembly behaviour is investigated. Several factors influence POC assembly, resulting in the formation of either vesicles or fibres. Design rules are introduced and used to predict and alter POC assembly morphology.

Systematic Adjustment of Pitch and Particle Dimensions within a Family of Chiral Plasmonic Gold Nanoparticle Single Helices.

Systematically controlling the assembly architecture within a class of chiral nanoparticle superstructures is important for fine-tuning their chiroptical properties. Here, we report a family of chiral gold nanoparticle single helices, varying in helical pitch and nanoparticle dimensions, that is assembled using a series of peptide conjugate molecules C-(PEP) (PEP = AYSSGAPPMPPF; x = 16-22). We demonstrate that the aliphatic tail length (i) can be used as a handle to systematically tune the helical pitch from 80 to 130 nm; and (ii) influences the size, shape, and aspect ratio of the component nanoparticles.

Peptide-Directed Assembly of Single-Helical Gold Nanoparticle Superstructures Exhibiting Intense Chiroptical Activity.

Chiral nanoparticle assemblies are an interesting class of materials whose chiroptical properties make them attractive for a variety of applications. Here, C-(PEP) (PEP = AYSSGAPPMPPF) is shown to direct the assembly of single-helical gold nanoparticle superstructures that exhibit exceptionally strong chiroptical activity at the plasmon frequency with absolute g-factor values up to 0.04.

Establishing Porosity Gradients within Metal-Organic Frameworks Using Partial Postsynthetic Ligand Exchange.

Crystalline 3-D materials bearing interlinked domains of differential porosity and functionality offer the potential for organizing and shuttling molecular and nanoscale matter to specific locations within 3-D space. Here, we present methods for creating prototype MOF materials that have such structural features. Specifically, the process of pore expansion via ligand exchange was studied for an isoreticular series of mesoporous MOFs based on bMOF-100.

Adjusting the Metrics of 1-D Helical Gold Nanoparticle Superstructures Using Multivalent Peptide Conjugates.

The properties of nanoparticle superstructures depend on many factors, including the structural metrics of the nanoparticle superstructure (particle diameter, interparticle distances, etc.). Here, we introduce a family of gold-binding peptide conjugate molecules that can direct nanoparticle assembly, and we describe how these molecules can be systematically modified to adjust the structural metrics of linear double-helical nanoparticle superstructures.