The Nhu Phan Research Group is located at the University of Gothenburg, department of chemistry and molecular biology. The research within the Phan group is focused on the development and applications of mass spectrometry imaging (ToF-SIMS, NanoSIMS, MALDI), fluoresence microscopy and super-resolution stimulated emission depletion (STED) microscopy, electron microscopy, and recently the correlative nanoscale imaging using combinations of these modalities to understand the structural and functional relationship of biomolecules in neural stem cells, neuronal cells and in the brain.
The developed technologies have been applied to the following biological questions:
- Organization of structural lipids at synaptic membrane, and its relation to neuronal activity.
- Targeted molecular imaging of the brain, structural and functional relation in brain activity.
- Molecular turnover in neuronal cells and brain, and correlation to neuro-degeneration.
- Molecular turnover, dynamics and regulation in neural stem cells.
- Stress granule pathway and molecular transition in neuronal cells.
We discovered an important relationship between the brain lipid organization and brain function modulated by exogenous factors (Phan, Anal. Chem. 2014), and between the lipid organization at neuronal membrane and the neuronal activity (Agüi-Gonzalez, ACS Chem.Neurosci. 2021). We further investigated the drug effects on structures and function of the brain and nerve cells (Philipsen, ACS Chem. Neurosci.2018, 2020). We measured the chemical distribution within single vesicles (Thomen, ACS Nano 2020; Rabasco, Int. J. Mol.Sci. 2022).
In another perspective, we have a strong interest in the development of novel labeling probes facilitating the correlative imaging. The probes contain elements that are visible in all the modalities, including SIMS, fluorescence microscopy, and electron microscopy, enabling multiplex targeted molecular imaging at micro- and nanoscale resolution.
We have developed dual labeling probes for protein imaging with SIMS and fluorescence microscopy (Kabatas, Angew. Chem. Int. Ed. 2019, J. Analyt. Atomic. Spec. 2019), and gold nanoprobes for SIMS and electron microscopy (Agüi-Gonzalez, Nanomaterials 2021). We have developed a correlative imaging method with NanoSIMS, fluorescence microscopy, and transmission electron microscopy to image cellular structure, location of specific proteins, and cellular compositions (Lange, PLOS ONE 2021), and a platform for correlative live imaging and analysis with confocal microscopy and amperometry to study the dynamics of individual secretary events of transmitter vesicles (Zheng, ACS Meas. Sci. Au 2021).
Ongoing research
Development of sample analysis pipeline for EM, STED, and SIMS
The use of correlative imaging increase data yield and research insight. We further aim to contribute to this by an improved ability to correlate samples via the development of an analytical pipeline to correlate electron microscopy (EM), STED-microscopy, NanoSIMS imaging, and ToF-SIMS imaging. This enables the analysis of the cellular molecular organization and dynamics at multiple levels, using one sample.
Schinzel–Giedion syndrome (SGS) research
SGS is a rare lethal congenital disease with severe neurological consequences. Through research collaboration with multiple partners, the use of super resolution imaging, and SIMS imaging we aim to investigate how lipids, morphology, and autophagy is affected by the disease and how treatment intervention can alleviate SGS-induced cellular dysregulation in neurons and oligodendrocytes
Synthesis of a novel probe to perform multi-modal correlative SIMS and fluorescence imaging
Correlative imaging using SIMS and fluorescence enables the use of gaining information on multiple molecular levels in one sample. However, this is mostly performed manually overlaying images based on sample morphology, mapping, and sample landmarks which can be labour intensive and difficult. However, we are aiming to improve correlative imaging of both techniques using a probe able to being detectable in both instruments. This provides improved multi-modal imaging with a higher ability of correlation and a higher specificity to target cellular components of interest.
The role of stress granules in ALS and neurodegenerative disease
The cause of neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) are complicated and appear to involve multiple biological factors. A component in neurodegenerative disease progression appear to be stress granules, an organelle with a vast array of cellular roles. We further aim to elucidate the roles of stress granules in neurodegenerative diseases such as ALS using super resolution microscopy and SIMS imaging.
The NanoSIMS Facility
NanoSIMS Sweden
The NanoSIMS Sweden facility (NanoSIMS Facility in Gothenburg) offers services in nanoscale ion mass spectrometry (NanoSIMS), a mass spectrometry imaging technique unique to the Nordic region. The NanoSIMS enables mass spectrometry imaging with a lateral resolution down to 50 nm.
NanoSIMS imaging can be applied in several fields such as material sciences, life science, geological sciences, and marine science.
- Experimental design and sample preparation
- NanoSIMS data acquisition, analysis, and processing
- Training and access to the NanoSIMS
Upcoming Events
Mass Spectrometry Imaging Zoom Seminar
Title: In Situ Liquid Secondary Ion Mass Spectrometry: A Unique Tool for In Situ Molecular Analysis of Solid–Liquid and Liquid–Vacuum Interfaces.
