Public defence, Chemical Engineering, MSc (Eng.) Alba Sanz Velasco

Title of the thesis: Controlling self-assembly in synthetic and biological systems to modulate photoluminescence

Thesis defender: Alba Sanz Velasco
Opponent: Prof. F. Akif Tezcan, University of California, San Diego, US
Custos: Prof. Mauri Kostiainen, Aalto University School of Chemical Engineering

Nature forms complex structures from simple components through self-assembly, a process in which molecules organize into ordered arrangements without external guidance. Since the interactions that hold these structures together are weak and reversible, they can adapt, reorganize, or disassemble in response to changing conditions.

This doctoral research explores how self-assembly can be controlled to create new light-emitting materials. By directing how biological and synthetic fluorescent molecules come together, their structure, stability, and brightness can be tuned. The work demonstrates several ways to apply this strategy. In one approach, minimal self-assembly was used to physically isolate fluorescent proteins within protein cages, improving their stability and helping preserve their light-emitting properties. In another, molecular self-assembly was deliberately enhanced in a family of aggregation-induced emission (AIE) fluorophores. These synthetic molecules become brighter when they cluster together, a feature particularly valuable for lighting applications. Finally, by carefully balancing the interactions that drive self-assembly, liquid-like droplets can be formed. This process serves as a preliminary step for interacting with different biomolecules such as DNA, silk proteins, and protein cages.

Overall, this research demonstrates that small changes at the molecular level can strongly influence how materials form and how they perform. By controlling self-assembly, materials can be designed with tailored optical properties and improved stability. These findings open new possibilities for more efficient and adaptable light-emitting materials, with potential applications in lighting, optoelectronics, and future biohybrid technologies.

Thesis available for public display 7 days prior to the defence at Aalto University's public display page.