Introduction To Peptide Self-Assembly

Self-assembling peptides refer to peptide materials that can form assemblies under certain conditions through intermolecular forces such as π-π stacking and electrostatic interactions. These peptides can assemble into a variety of nanostructures, such as nanofibers, nanotubes, and hydrogels, depending on their specific sequence and environmental conditions. Self-assembling peptides have attracted significant attention in the field of biomaterials and regenerative medicine due to their ability to mimic the extracellular matrix and provide a supportive environment for cell growth and tissue regeneration. Additionally, the tunability of self-assembling peptides allows for the design of materials with specific properties and functions tailored to the desired application.

Fig.1 Self-assembling peptides^[1]

Applications of Self-Assembling Peptides

Tissue engineering. Self-assembling peptides can be used to create scaffolds that mimic the extracellular matrix, providing a supportive environment for the growth and differentiation of cells in tissue engineering and regenerative medicine.
Drug delivery. Self-assembling peptides can be engineered to encapsulate and deliver drugs or biomolecules to specific targets in a controlled and sustained manner, improving the efficacy and safety of therapeutic interventions.
Biosensing. Self-assembling peptides can be functionalized with specific recognition motifs or responsive elements to detect and signal the presence of target molecules or environmental changes, enabling the development of sensitive and selective biosensors.
Wound healing. Self-assembling peptides can be utilized in wound dressings or topical formulations to promote tissue repair and regeneration, thanks to their ability to enhance cell migration, angiogenesis, and collagen synthesis in the wound site.
Biomimetic materials. Self-assembling peptides can be used to prepare biomimetic materials, such as biomimetic membranes, biomimetic fibers, and biomimetic hydrogels, which are biocompatible and biodegradable.
Photonics. Self-assembling peptides have potential applications in the field of photonics and can be used to prepare photonic crystals, photonic waveguides, and optical sensors.

Factors Affecting Peptide Self-Assembly

Peptide sequence. The amino acid sequence of a peptide plays a crucial role in its ability to self-assemble. Peptides with specific sequences that promote interactions such as electrostatic attraction, hydrogen bonding, or hydrophobic interactions tend to self-assemble more readily.
Peptide concentration. The concentration of peptides in solution can affect their self-assembly behavior. Higher concentrations of peptides provide more opportunities for peptide-peptide interactions, leading to increased self-assembly.
Ions or other molecules. Ions can interact with peptides and alter their conformation or stability, while other molecules can compete for binding sites and disrupt the self-assembly process.

pH and temperature. The important core driving force for the self-assembly of peptides is the formation of hydrogen bonds between molecules. However, the formation of hydrogen bonds is easily affected by pH. Changing the pH of the solution will cause the C-terminus and N-terminus of the peptide chain or some chemical groups to become positively or negatively charged. This means that peptides with positive and negative charges are formed, thereby showing different self-assembly trends, nanostructures and structural functional characteristics. In addition, the increase in temperature will destroy the hydrogen bonds of the system, weaken the stability of the self-assembly system, and thus cause conformational changes.
External stimuli. External stimuli such as light or mechanical forces can also impact peptide self-assembly. These stimuli can trigger conformational changes or induce aggregation of peptides, leading to altered self-assembly behavior.

Reference

Du, Z.; et al. Supramolecular peptide nanostructures: Self-assembly and biomedical applications. Giant. 2022, 9, 100082.