Literature Sharing: "Adaptive peptide dispersions enable drying-induced biomolecule encapsulation"

       Today we are sharing a research article led by Professors Rein V. Ulijn and Ye He from the Advanced Science Research Center at the City University of New York, published in Nature Materials, titled "Adaptive peptide dispersions enable drying-induced biomolecule encapsulation." This study reports a dynamically soluble dispersion formed by minimal tripeptide sequences, which enables efficient encapsulation and protection of biomolecules such as proteins through drying-induced liquid-liquid phase separation (LLPS). The research draws inspiration from natural biological strategies employed by organisms to combat dehydration stress (Fig. 1).

Fig.1. Directionality and dispersibility in peptide self-assembly.

01 Research Background

       Peptides serve as key building blocks for functional materials, and their assembly is typically governed by backbone hydrogen bonding, leading to the formation of well-defined directional structures such as one-dimensional (1D) fibers or two-dimensional (2D) sheets. However, biology widely exhibits non-directional, flexible, and adaptable assemblies, such as liquid condensates. Inspired by natural strategies employed by tardigrades and plant seeds, which utilize liquid-liquid phase separation and a glassy state to protect macromolecules under extreme dehydration, this study aims to develop a simple, efficient, and bioactivity-preserving strategy for drying-induced encapsulation.

       This work introduces a class of minimal tripeptide sequences composed of tryptophan (W), tyrosine (Y), and lysine (K). These peptides form highly soluble dynamic ensembles in aqueous solution through abundant side-chain interactions (Fig. 2a). A key finding is that dispersions of these peptides undergo a unique liquid-liquid phase separation during air drying, subsequently solidifying into rigid, dense, and porous microsphere particulate films. These films can rapidly redisperse upon rehydration and efficiently encapsulate proteins or small-molecule payloads from solution, maintaining protein stability and activity after resolubilization (Fig. 2).

​Fig. 2. Sequence dependence in tripeptide dispersions.

02 Innovative Highlights

✓ Introduced a new paradigm of "side-chain-dominated" peptide assembly: This approach transcends the limitations of traditional peptide assembly, which relies on backbone hydrogen bonding to form directional structures. Instead, it leverages multiple weak interactions among aromatic and basic amino acid side chains to create dynamic, soluble, and environmentally adaptive peptide ensembles.

✓ Discovered drying-induced liquid-liquid phase separation (LLPS) in peptides: The mechanism of evolution from dynamic dispersions → liquid condensate droplets → porous rigid particles was systematically elucidated (Fig. 3), a process highly analogous to protective strategies found in nature.

✓ Developed an efficient and mild one-step platform for biomolecule encapsulation and protection: This method requires no complex equipment or harsh conditions. Efficient encapsulation and long-term ambient-temperature storage of biomolecules are achieved simply through air drying, with the process being highly reversible (Fig. 3).

Fig. 3.Evaporation-driven assembly.

03 Results and Discussion

✓ Molecular Simulations and Sequence Dependence of Tripeptide Dispersions​
     Using all-atom molecular dynamics (MD) simulations, the researchers compared the assembly propensity (AP) of tripeptides such as KFF, KYF, KYY, and KYW. It was found that along the sequence variation F → Y → W, the total number of hydrogen bonds increased, while backbone hydrogen bonds decreased and side-chain hydrogen bonds increased. This shift resulted in KYW exhibiting non-directional assembly characteristics (Fig. 2a).

✓ Evaporation-Driven Assembly and Phase Behavior Characterization​
     When 20 mM peptide solutions were dried in droplet form, all K/Y/W isomers exhibited drying-induced phase separation, forming films composed of densely packed spherical particles (Fig. 3d). Time-lapse confocal microscopy captured the detailed process: dynamic ensembles → formation of spherical droplets (LLPS) → droplet fusion → solidification accompanied by pore formation (Fig. 3e–g).

✓ Formation Mechanism of Buoyant Droplets and Porous Particles​
     Analysis of the dried films revealed that the particles mostly exhibited porous hemispherical structures (Fig. 4a–c). The researchers proposed that buoyancy is related to the formation of internal bubbles within the droplets. Water evaporation leads to dehydration of the peptide structure, which is replaced by air, resulting in microcavitation and the formation of a porous architecture (Fig. 4).

Fig. 4. Formation of buoyant droplets and porous particles.

✓ Size/Shape Control and Process Reversibility​
     The study revealed that the size and uniformity of the resulting particles can be precisely controlled by adjusting the drying conditions. Increasing the temperature or buffer salt concentration accelerates the phase transition process, yielding smaller and more monodisperse particles (Fig. 5a-d). Importantly, the entire process is fully reversible (Fig. 5).

Fig. 5.Size control, shape control and reversibility.

✓ Drying-Induced Encapsulation and Preservation Applications​
     The core application of this study is the encapsulation and preservation of biomolecules. The proposed mechanism is as follows: the payload first forms non-covalent complexes with the dynamic peptide ensembles in solution via electrostatic, π–π, and other interactions, and is then efficiently entrapped within the droplets formed during drying-induced liquid–liquid phase separation (Fig. 6a). Experiments demonstrated that both small-molecule dyes and model proteins can be efficiently encapsulated (Fig. 6b–c). Functional assays showed that EGFP encapsulated by the peptides retained strong fluorescence after five days of storage in the dried state and subsequent rehydration (Fig. 6d–f).

Fig. 6. Drying-induced encapsulation and protection.

04 Conclusion

      This study challenges the conventional paradigm of peptide self-assembly dominated by backbone hydrogen bonding. By designing minimal tripeptide sequences composed of tryptophan, tyrosine, and lysine, the researchers created dynamic soluble dispersions governed primarily by multiple weak side-chain interactions. These dispersions undergo a unique drying-induced liquid-liquid phase separation, spontaneously forming rigid, porous, and reversible microsphere particles. This system enables efficient one-step encapsulation of biomolecules like proteins while providing exceptional stability protection in the dried state.

      As Professor Ye He noted, "The protein encapsulation efficiency was remarkably high. We hadn't anticipated that such short peptide sequences could achieve such outstanding protective performance." Professor Rein Ulijn added, "This work not only reveals a novel mechanism of peptide self-organization but also introduces an extremely simple yet practical materials platform for biotechnology applications."

     The research establishes a new paradigm of environmentally adaptive peptide assembly dominated by side-chain chemistry, advancing fundamental knowledge in supramolecular chemistry and materials science. Simultaneously, it develops a simple, versatile, and scalable platform for biomolecule preservation, successfully bridging basic discovery and practical application. The complete research trajectory—from bio-inspiration to technological innovation and implementation—demonstrates broad application prospects spanning cold-chain-free vaccine transport, smart drug delivery, biosensing, and tissue engineering scaffolds. The team has already validated the preparation of functional microparticles using industry-friendly methods like spray-drying, laying groundwork for industrial application and providing valuable insights for future biomaterial design.Link Text