The Functional Inorganic Materials research group (FUNIMAT) at the Institute of Molecular Science (ICMol) of the University of Valencia (UV) has developed a new synthetic strategy to design porous materials capable of modifying their structure in a controlled manner in response to molecules in their environment.
The work originates from the ERC project LIVINGPORE, led by Carlos Martí Gastaldo, head of the FUNIMAT group and lecturer in the Department of Inorganic Chemistry at the UV. It proposes a modular platform based on synthetic amino acids that combines chemical stability with adaptive capacity — two properties that are difficult to integrate in this class of materials.
Published in the journal Chem, the study introduces a new family of crystalline structures called MUV-X (Materials of the Universitat de València), where X denotes the amino acid used. These materials are constructed from modified peptides and zinc metal centres and belong to the family of metal–organic frameworks (MOFs), porous solids with internal cavities capable of hosting small molecules.
Some MOFs exhibit structural flexibility, allowing them to change pore size or shape in response to the molecules with which they interact. However, integrating such dynamic behaviour without compromising chemical stability has been a major challenge in the development of this type of porous architecture. ICMol researchers addressed this problem by drawing inspiration from proteins, where rigid regions coexist with flexible segments that enable reversible conformational changes without loss of structural integrity.
“Proteins can adapt to their environment while maintaining structural integrity. Our goal was to transfer this balance between rigidity and flexibility to the design of synthetic materials”, explains Martí-Gastaldo, head of the FUNIMAT team.
Following this concept, the team designed molecular linkers based on amino acids modified with chemical units known as pyrazoles. These form rigid metal chains that provide structural support, while the peptide backbone introduces controlled mobility. According to the authors, this combination enables robustness and adaptability to coexist within a single material.
The study shows that the amino acid employed determines the final architecture of the material. Using alanine produced a three-dimensional network (MUV-A), whereas bulkier amino acids such as phenylalanine or tyrosine yielded stacked two-dimensional layered structures (MUV-F and MUV-Y).
In addition to determining the shape of the material, the amino acid identity also modulates how the material responds to external molecules. As co-author Natalia M. Padial notes, “the identity of the amino acid not only defines the final structure, but also how the material responds to external molecules”.
Selective Response to Solvents
Experiments show that some of these materials reorganise their structure when interacting with specific solvents, altering pore size and shape. In particular, the three-dimensional MUV-A displays particularly high flexibility, expanding or contracting depending on the guest molecule within its pores. By contrast, the layered variants exhibit more selective responses governed by specific interactions such as hydrogen bonding or aromatic contacts.
Combined structural experiments and computational simulations revealed that these transformations are driven by interactions between the guest molecules and the material’s peptide backbone.
A key achievement of this work is the materials’ stability. Unlike most peptide-based frameworks, which typically degrade in water or collapse when solvent is removed, these new networks retain crystallinity and porosity even under acidic, basic or moderately hydrothermal conditions.
Towards Programmable Porous Materials
According to the researchers, this strategy opens the door to designing porous materials whose structural response can be programmed through amino acid selection.
“This approach allows us to design materials that are simultaneously flexible and robust, in which we can precisely define the chemical environment of the pore by choosing the right amino acid. It represents an important step towards porous platforms whose structural response can be rationally programmed according to the molecule we wish to recognise”, explains co-author Víctor Carratalá.
Potential future applications include molecular recognition, selective separation of enantiomers and activation of chiral molecules — fields in which both stability and adaptability are essential.
Reference: Carratalá, V. et al. Synthetic Amino Acids for Programming Adaptive Response in Pyrazolate Peptide Frameworks. Chem (2026). https://doi.org/10.1016/j.chempr.2026.102992