
PICMI-AFM core facility is dedicated to the study of biological samples for nanometric imaging, and/or for the study of their mechanical properties. Before PICMI-AFM creation (2012), there was no AFM biological core facility in the whole Region Sud and it remains unique to date. Thanks to PICMI-AFM, IRCAN has filled a scientific and technical void. This facility is a member of MICA multi-site platform (Microscopie Imagerie Cytométrie Azur).
The Atomic Force Microscopy (AFM) is based on the physical interaction between the AFM probe and the sample surface. The probe measures the forces of interaction (attractive or repulsive) with the sample surface, which depend monotonously on the distance.
These measurements can be used for two scientific purposes:
- for imaging, by obtaining 3D images at nanometric resolution
- for studying the mechanical properties of the sample, such as elasticity, by means of what is known as nanoindentation
The advantages of the technique lie in the almost no sample preparation requirement that leaves the native surface unaltered, in the possibility of performing the experiment in a liquid environment (physiological condition) and in the wide spectrum of applications (from DNA to tissue) . Besides, AFM is a single molecule technique, so measurements give distributions with a full statistical description and detection of intermediates and rare events.


Expertise and Service offer/ Applications
AFM-PICMI Services include:
- AFM imaging combined with bright-field/fluorescence microscopy
- Topographical imaging of samples in air or liquid environments
- Studies and analysis of nanomechanical properties of samples (elasticity)
- Data analysis for the determination of samples roughness, size distribution, conformational changes, 3D imaging.
- Support and counseling for researchers.
- Project feasibility analysis and strategy design : suitable sample preparation and AFM protocols (protocols are adapted, optimized or developed)
AFM-PICMI Applications include:
- Proteins and Protein complexes
- DNA and RNA
- DNA-protein and RNA-protein complexes
- Cells and cell membranes
- Exosomes
- Spheroids
- Tissues
Members

Sabrina PISANO IR Inserm
Scientific manager
Tel: +33 (0)4 93 37 70 17
Email: sabrina.pisano@univ-cotedazur.fr
Equipment
Multimode 8 (Bruker)
This instrument is thought for high resolution. It is dedicated to the study of small samples (DNA, RNA, proteins, nucleoprotein complexes, cellular membranes). It allows several operating modes (contact, tapping, peak force tapping) and can be used in air and liquid.
This AFM has three different scanners used depending on the sample size:
125 x 125 x 5μm XYZ
4 x 0.4 x 0.4μm XYZ
10 x 10 x 2.5μm YYZ

Bioscope Catalyst (Bruker)
This instrument is thought for the study of larger samples (metaphase chromosomes, cells, tissues). It allows several operating modes (contact, tapping, peak force tapping) and can be used in air and in liquid. Scanner available ≥ 150μm XY, ≥ 20μm Z.
This AFM is coupled to an inverted optical microscope (Leica Microsystems DMI 6000B) able to do bright-field, phase-contrast or fluorescence imaging. By the coupling it is possible to pinpoint the area of interest and to take advantage of both the techniques. With the Bioscope Catalyst it is possible to work in a controlled liquid environment (temperature and composition)

Getting started/ Access
Tell us about your project!

Teams wishing to take advantage of the AFM technology for biology, are invited to contact Sabrina PISANO by sending a message to sabrina.pisano@univ-cotedazur.fr or come and talk to her for fixing a meeting. During this first appointment, users will specify their biological question to help us decide together on the most suitable AFM approach.
In our policy, AFM-PICMI is not an independent user facility. The only person authorized to use the microscopes is the facility Manager, who ensures the proper functioning of the devices (troubleshooting, experiments, data analysis)
Publications
- par Alain CorinusBasement membranes (BM) are thin, nanoporous sheets of specialized extracellular matrix (ECM) that line epithelial tissues. They are dynamic structures that serve multiple key functions, as evidenced by numerous diseases, including cancer progression, that are associated with their alterations. Our understanding of the BM and its communication with adjoining epithelial cells remains highly fragmented due to the BM's complex molecular architecture, the lack of molecular tools, limitations in…
- par Swarnabh BhattacharyaThe cell fate decisions of stem cells (SCs) largely depend on signals from their microenvironment (niche). However, very little is known about how biochemical niche cues control cell behavior in vivo. To address this question, we focused on the corneal epithelial SC model in which the SC niche, known as the limbus, is spatially segregated from the differentiation compartment. We report that the unique biomechanical property of the limbus supports the nuclear localization and function of…
- par Raphaël BoncheAll epithelia have their basal side in contact with a specialized extracellular matrix, the basement membrane (BM). During development, the BM contributes to the shaping of epithelial organs via its mechanical properties. These properties rely on two core components of the BM, collagen type IV and perlecan/HSPG2, which both interact with another core component, laminin, the initiator of BM assembly. While collagen type IV supplies the BM with rigidity to constrain the tissue, perlecan…
- par Christopher RoveraFibroblastic reticular cells (FRC) are immunologically specialized myofibroblasts that control the elasticity of the lymph node, in part through their contractile properties. Swelling of tumor-draining lymph nodes is a hallmark of lymphophilic cancers such as cutaneous melanoma. Melanoma displays high intratumoral heterogeneity with the coexistence of melanoma cells with variable differentiation phenotypes from melanocytic to dedifferentiated states. Factors secreted by melanoma cells promote…
- par Ilona BerestjukResistance to BRAF/MEK inhibitor therapy in BRAF^(V600) -mutated advanced melanoma remains a major obstacle that limits patient benefit. Microenvironment components including the extracellular matrix (ECM) can support tumor cell adaptation and tolerance to targeted therapy; however, the underlying mechanisms remain poorly understood. Here, we investigated the process of matrix-mediated drug resistance (MMDR) in response to BRAF^(V600) pathway inhibition in melanoma. We demonstrate that physical…
- par Stéphanie TorrinoMechanical signals from the tumor microenvironment modulate cell mechanics and influence cell metabolism to promote cancer aggressiveness. Cells withstand external forces by adjusting the stiffness of their cytoskeleton. Microtubules (MTs) act as compression-bearing elements. Yet how cancer cells regulate MT dynamic in response to the locally constrained environment has remained unclear. Using breast cancer as a model of a disease in which mechanical signaling promotes disease progression, we…
- par Georgios EfthymiouCellular fibronectin (FN; also known as FN1) variants harboring one or two alternatively spliced so-called extra domains (EDB and EDA) play a central bioregulatory role during development, repair processes and fibrosis. Yet, how the extra domains impact fibrillar assembly and function of the molecule remains unclear. Leveraging a unique biological toolset and image analysis pipeline for direct comparison of the variants, we demonstrate that the presence of one or both extra domains impacts FN…
- par Christophe A GirardAberrant extracellular matrix (ECM) deposition and stiffening is a physical hallmark of several solid cancers and is associated with therapy failure. BRAF-mutant melanomas treated with BRAF and MEK inhibitors almost invariably develop resistance that is frequently associated with transcriptional reprogramming and a de-differentiated cell state. Melanoma cells secrete their own ECM proteins, an event that is promoted by oncogenic BRAF inhibition. Yet, the contribution of cancer cell-derived ECM…
- Cyclic uniaxial mechanical stretching of cells using a LEGO® parts-based mechanical stretcher systempar Etienne BoulterMechanical cues are essential for the regulation of cell and tissue physiology. Hence, it has become an utmost necessity for cell biologists to account for those mechanical parameters when investigating biological processes and they need devices to manipulate cells accordingly. Here, we report a simple mechanical cell-stretching system that can generate uniaxial cyclic mechanical stretch on cells in tissue culture. This system is based upon a low-cost battery-powered uniaxial cyclic mechanical…
- par Marianne Stemann AndersenThe sebaceous gland (SG) is an essential component of the skin, and SG dysfunction is debilitating^(1,2). Yet, the cellular bases for its origin, development and subsequent maintenance remain poorly understood. Here, we apply large-scale quantitative fate mapping to define the patterns of cell fate behaviour during SG development and maintenance. We show that the SG develops from a defined number of lineage-restricted progenitors that undergo a programme of independent and stochastic cell fate…
- par Julien Cherfils-ViciniMyeloid-derived suppressor cells (MDSCs) are immature myeloid cells with strong immunosuppressive activity that promote tumor growth. In this study, we describe a mechanism by which cancer cells control MDSCs in human cancers by upregulating TRF2, a protein required for telomere stability. Specifically, we showed that the TRF2 upregulation in cancer cells has extratelomeric roles in activating the expression of a network of genes involved in the biosynthesis of heparan sulfate proteoglycan,…
- par Stéphanie TorrinoUbiquitin domain-containing protein 1 (UBTD1) is highly evolutionary conserved and has been described to interact with E2 enzymes of the ubiquitin-proteasome system. However, its biological role and the functional significance of this interaction remain largely unknown. Here, we demonstrate that depletion of UBTD1 drastically affects the mechanical properties of epithelial cancer cells via RhoA activation and strongly promotes their aggressiveness. On a stiff matrix, UBTD1 expression is…
- par Etienne BoulterMechanical and metabolic cues independently contribute to the regulation of cell and tissue homeostasis. However, how they cross-regulate each other during this process remains largely unknown. Here, we show that cellular metabolism can regulate integrin rigidity-sensing via the sphingolipid metabolic pathway controlled by the amino acid transporter and integrin coreceptor CD98hc (SLC3A2). Genetic invalidation of CD98hc in dermal cells and tissue impairs rigidity sensing and mechanical signaling…
- par Sabrina PisanoAtomic force microscopy (AFM) is a non-optical microscopy that enables the acquisition at the nanoscale level of a 3D topographical image of the sample. For 30 years, AFM has been a valuable tool in life sciences to study biological samples in the field of tissue, cellular and molecular imaging, of mechanical properties and of force spectroscopy. Since the early beginnings of the technique, AFM has been extensively exploited as an imaging tool for structural studies of nucleic acids and…
- par Thomas BerteroDysregulation of extracellular matrix (ECM) deposition and cellular metabolism promotes tumor aggressiveness by sustaining the activity of key growth, invasion, and survival pathways. Yet mechanisms by which biophysical properties of ECM relate to metabolic processes and tumor progression remain undefined. In both cancer cells and carcinoma-associated fibroblasts (CAFs), we found that ECM stiffening mechanoactivates glycolysis and glutamine metabolism and thus coordinates non-essential amino…
- par Eloise M GrassetIn squamous cell carcinoma (SCC), tissue invasion by collectively invading cells requires physical forces applied by tumor cells on their surrounding extracellular matrix (ECM). Cancer-related ECM is composed of thick collagen bundles organized by carcinoma-associated fibroblasts (CAF) within the tumor stroma. Here, we show that SCC cell collective invasion is driven by the matrix-dependent mechano-sensitization of EGF signaling in cancer cells. Calcium (Ca^(2+)) was a potent intracellular…
- par Sabrina PisanoIn this issue of Molecular Cell, Kim et al. (2017) have studied the structure and organization of the shelterin protein complex protecting telomeres in Schizosaccharomyces pombe and humans and discovered an allosteric structural transition that drives the formation of the shelterin complex and participates in telomere length regulation.
- par Silvia BottiniThere is a growing body of evidence about the presence and the activity of the miRISC in the nucleus of mammalian cells. Here, we show by quantitative proteomic analysis that Ago2 interacts with the nucleoplasmic protein Sfpq in an RNA-dependent fashion. By a combination of HITS-CLIP and transcriptomic analyses, we demonstrate that Sfpq directly controls the miRNA targeting of a subset of binding sites by local binding. Sfpq modulates miRNA targeting in both nucleoplasm and cytoplasm, indicating…
- par Delphine Benarroch-PopivkerThe shelterin proteins protect telomeres against activation of the DNA damage checkpoints and recombinational repair. We show here that a dimer of the shelterin subunit TRF2 wraps ∼ 90 bp of DNA through several lysine and arginine residues localized around its homodimerization domain. The expression of a wrapping-deficient TRF2 mutant, named Top-less, alters telomeric DNA topology, decreases the number of terminal loops (t-loops), and triggers the ATM checkpoint, while still protecting telomeres…
- par Guillaume GaullierTelomere integrity is essential to maintain genome stability, and telomeric dysfunctions are associated with cancer and aging pathologies. In human, the shelterin complex binds TTAGGG DNA repeats and provides capping to chromosome ends. Within shelterin, RAP1 is recruited through its interaction with TRF2, and TRF2 is required for telomere protection through a network of nucleic acid and protein interactions. RAP1 is one of the most conserved shelterin proteins although one unresolved question…



