In the world of material science, the development of advanced materials represents a leap beyond traditional substances, offering specialized properties like mechanical strength, flexibility, conductivity, hydrophobicity/hydrophilicity, and traits crucial for sensing (e.g., molecular affinity), cell interactions (e.g., biocompatibility), and nanomedicines (e.g., targeting precision) in cutting-edge applications. At the Institute for Complex Molecular Systems (ICMS) at TU/e, this shines through two domains: Advanced Materials, where molecular design crafts smart polymers, durable coatings, or sensor-ready surfaces, and Engineering Life, which creates biomaterials for tissue engineering and drug delivery nanosystems.
Here we want to highlight three examples demonstrating how super-resolution microscopy, including advanced multimodal approaches, is driving innovation in material design and characterization. These examples underscore the power of SRM to bridge the gap between theoretical models and experimental observations, enabling the development of advanced materials with tailored properties.
Case 1: Visualizing Self-Assembly in Functional Materials
Challenge
In material science, a key challenge driving interest in supramolecular structures is understanding how their self-assembly works: how simple building blocks spontaneously organize into complex systems through weak, reversible interactions. Scientists are drawn to these materials because their adaptability and tunability make them ideal for cutting-edge uses: smart sensors that respond to environmental cues, drug delivery systems that release contents precisely, or self-healing surfaces that repair themselves. The puzzle lies in decoding the dynamics of this self-assembly—whether it’s localized or uniform across the structure—to fully exploit their potential for such innovative applications. However, understanding and controlling the self-assembly process requires detailed insights into how individual molecules interact and organize themselves. Traditional microscopy techniques are often insufficient to resolve these dynamic processes at the molecular level.
Solution
Using STORM (Stochastic Optical Reconstruction Microscopy), we, researchers at TU/e were able to visualize the self-assembly of block copolymers, a class of materials that can form highly ordered nanostructures. In the 2014 Science study by Albertazzi et al., STORM revealed how one-dimensional supramolecular aggregates—self-assembled from synthetic building blocks like 1,3,5-benzenetricarboxamide (BTA)—exchange monomers homogeneously along their backbone, challenging previous assumptions assumptions.
Impact
SRM helped us significantly update the knowledge of supramolecular assembly in one-dimensional aggregates by revealing that monomer exchange occurs uniformly along the entire fiber, not just at the ends, which is an important consideration when we are building functional aggregates out of these blocks. This insight enhanced our grasp of molecular adaptability, fueling better designs for responsive advanced materials like sensors and drug delivery systems and more.
Lorenzo Albertazzi et al. ,Probing Exchange Pathways in One-Dimensional Aggregates with Super-Resolution Microscopy.Science344,491-495(2014).DOI:10.1126/science.1250945
Case 2: Investigating Heterogeneous Protein Coatings on Silica Porous Surfaces with STED Microscopy
Challenge
Protein coatings on porous silica surfaces are widely used in applications such as biosensors, drug delivery systems, and catalytic supports. However, the heterogeneity of these coatings—both on the surface and within the pores—poses a significant challenge for characterization. Understanding the distribution, density, and conformation of proteins at the nanoscale is critical for optimizing the performance of these materials.
Solution
We employed STED (Stimulated Emission Depletion) microscopy to investigate the heterogeneous components of protein coatings on and within silica porous surfaces. STED microscopy overcomes the diffraction limit by using a donut-shaped laser beam to deactivate fluorescence in the outer regions of the focal spot, achieving resolutions of 20–50 nanometers. This allows researchers to map the distribution of fluorescently labeled proteins with exceptional detail, even within the complex 3D structure of porous silica.
Impact
Using STED microscopy, we uncovered previously hidden heterogeneities in protein coatings, such as variations in protein density and clustering within the pores. These insights have led to the development of more uniform and efficient coatings, improving the performance of biosensors and drug delivery systems. For example, by optimizing the protein distribution, researchers have enhanced the sensitivity of biosensors and the controlled release of therapeutic agents from porous silica carriers.
Wang Y, Soto Rodriguez PED, Woythe L, Sánchez S, Samitier J, Zijlstra P, Albertazzi L. Multicolor Super-Resolution Microscopy of Protein Corona on Single Nanoparticles. ACS Appl Mater Interfaces. 2022 Aug 24;14(33):37345-37355. doi: 10.1021/acsami.2c06975
Case 3: Multimodal Microscopy for Comprehensive Material Characterization
Challenge
Understanding the behavior of advanced materials often requires more than just high-resolution imaging, this is because of the complex, heterogeneous and nanoscale nature of materials. No single microscopy technique can provide a complete picture, as different techniques offer varying contrasts, resolutions, and sensitivities to specific properties such as morphology, composition, molecular orientation and mechanical properties. Approaches or workflows to combine different microscopy modalities are needed.
Solution
We are leveraging multimodal microscopy, including spectrally and orientation-resolved single-molecule microscopy and correlative microscopy, to address these challenges.
Spectrally and Orientation-Resolved Single-Molecule Microscopy: By combining single-molecule localization with spectral and orientation information, researchers can study the electronic properties and alignment of molecules within a material. For example, this approach has been used to investigate the orientation of dye molecules in organic semiconductors, which is critical for optimizing light absorption and charge transport in solar cells.
Correlative Microscopy: This technique integrates super-resolution microscopy with other imaging modalities, such as electron microscopy (EM) or atomic force microscopy (AFM). By correlating data from different techniques, researchers can link nanoscale structural features with functional properties. For instance, correlative microscopy has been used to study the relationship between the nanoscale morphology of polymer blends and their mechanical performance.
Impact
Multimodal microscopy has provided critical insights into the design of advanced materials. For example, in the development of supramolecular materials, spectrally and orientation-resolved single-molecule microscopy has revealed how molecular property and physical arrangement affect their mechanical property. Correlative EM and AFM microscopy further enhance the resolution down to nanometers, offering a complete picture from structure details to molecule specificity. These advancements are driving innovation in fields such as biomaterial development, drug delivery and smart nanomedicine.
Wang Y, Friedrich H, Voets IK, Zijlstra P, Albertazzi L. Correlative imaging for polymer science. J Polym Sci. 2021; 59: 1232–1240. https://doi.org/10.1002/pol.20210013
Emmanouil Archontakis, Linlin Deng, Peter Zijlstra, Anja R. A. Palmans, and Lorenzo Albertazzi. Journal of the American Chemical Society 2022 144 (51), 23698-23707 DOI: 10.1021/jacs.2c11940
Fu, H., Huang, J., van der Tol, J.J.B. et al. Supramolecular polymers form tactoids through liquid–liquid phase separation. Nature 626, 1011–1018 (2024). https://doi.org/10.1038/s41586-024-07034-7
The Role of the Advanced Microscopy Facility
The Advanced Microscopy Facility (www.superresolution.nl ) at TU/e plays a critical role in enabling these breakthroughs. Equipped with state-of-the-art super-resolution microscopes, including STED, and STORM, as well as multimodal imaging capabilities, the facility provides researchers with the tools and expertise needed to push the boundaries of material science. From visualizing self-assembly processes in living cells and synthetic materials and performing quantitative single-molecule analysis, the facility supports a wide range of applications that drive innovation in material design and characterization. The facility also emphasizes collaboration and training, ensuring that researchers can fully leverage the potential of super-resolution microscopy. By combining advanced imaging technologies with interdisciplinary research, the Advanced Microscopy Facility is helping to shape the future of material science.
Read more about the innovative work of the facility in material science research in the new book “Super-Resolution Microscopy for Materials Science” by Albertazzi and Zijlstra,
https://www.routledge.com/Super-Resolution-Microscopy-for-Material-Science/Albertazzi-Zijlstra/p/book/9781032103679