This is a selected list of the research projects I was involved
Current research projects
At TU delft I am working to develop a new optical technique to study protein (un)folding dynamics, ideally at single-molecule level.
Past research projects
At Single-Molecule Optics Group, Leiden University
Fluorescence enhancement using individual gold nanorods
Recently we used the technique named DNA transient binding to repetitively place individual molecules in the near field of a single gold nanorod.
- Publication: Zhang, W., Caldarola, M., Lu, X., Pradhan, B. and Orrit, M. Single-molecule fluorescence enhancement of a near-infrared dye by gold nanorods using DNA transient binding. Phys. Chem. Chem. Phys. 20, 20468-20475 (2018) (link).
We presented a innovative way to compute enhancement factors from time-correlated single-photon counting experiments that avoids arbitrary binning of the data. We called this ‘binning free’ analysis and we showed that it provides relaiable and consistent results with the other methods used in the literature.
- Publication: Caldarola, M., Pradhan, B., Orrit, M. Quantifying fluorescence enhancement for slowly diffusing single molecules in plasmonic near fields. The Journal of chemical physics 148.12: 123334 (2018). (link)
Nonlinear signals enhanced by gold nanorods
We showed, for the first time at room temperature, enhancement of two-photon-excited luminescence of single semiconductor quantum dots. To achieve this, we used gold nanorods to concentrate the field in a sub-difraction volume and showed an enhancement factor of more than 10.000!
- Zhang, W., Caldarola, M., Lu, X., and Orrit, M. Plasmonic Enhancement of Two- Photon-Excited Luminescence of Single Quantum Dots by Individual Gold Nanorods, ACS Photonics 5, 7, 2960-2968 (2018). (link).
Gold nanorods as nanothermometers
We used the anti-Stokes photoluminescence emission to measure the absolute temperature of an individual gold nanorods. This method provides a way to access the temperature in the surrounding media of a gold nanorod without the need of any temperature calibration.
- Publication: Carattino, A., Caldarola, M. and Orrit, M. Gold nanoparticles as absolute nanothermometers. Nano Letters 18, 2, 874-880. (2018) (link)
We used enhanced-fluorescence detection to optical study the electrochemical properties of single methylene blue molecules.
Publication: Zhang, W., Caldarola, M., Pradhan, B. and M. Orrit. Gold Nanorod Enhanced Fluorescence Enables Single-Molecule Electrochemistry of Methylene Blue. Angewandte Chemie International Edition, 56(13), 3566-3569. (link)
At Quantum Electronics Laboratory, University of Buenos Aires
During my PhD I worked on a combined multipropose microscope. It combined a home-made atomic force microscopy with a fluorescence wide field and confocal optical microscope.
With this setup I studied novel dielectric nanoantennas that provide good fluorescence enhancement and SERS capabilities with ultralow heat generation.
- Publication: Caldarola, M., Albella, P., Cortés, E., Rahmani, M., Roschuk, T., Grinblat, G., Oulton, R.F., Bragas, A.V. and Maier, S.A. Non-plasmonic nanoantennas for surface enhanced spectroscopies with ultra-low heat conversion. Nature Communications, 6:7915 (2015) (link).
I also collaborated with biophysics researches, working on a problem in the area of mechanotransduction. We studied the formation of focal adhesion proteins when we apply a controlled, local and functional mechanical stimulus on a live cell.
- Publication: von Bilderling, C., Caldarola, M., Masip, M. E., Bragas, A. V., Pietrasanta, L. I., Monitoring in real-time focal adhesion protein dynamics in response to a discrete mechanical stimulus. Review of Scientific Instruments 88, 013703 (2017) (link)