Responses of biological tissues to mechanical stress are increasingly assessed, owing to their demonstrated link to many biological functions and the onset and progression of various pathologies such as fibrosis or ischemia. The study of these phenomena implies the need of new technologies enabling concomitant stimulation and characterization of the tissue. Materials that can be tuned by an external stimulus have been thus increasingly assessed for applications linked to biology. Among them, stimuli-responsive hydrogels are essential, owing to their naturally high content of water. In this topic, the GELLIGHT project aims at developing biocompatible hydrogels, the stiffness of which can be reversibly tuned by light and which will be used as active sample holders for photonic microscopy of 3D-cultured cardiac cells. For this, dual chemical and reversible physical (based on host-guest interactions) crosslinking will be used and the biological tissue encapsulated directly inside the hydrogels.
The originality of GELLIGHT stands at different levels:
- the possibility to obtain large stiffness variation in a biocompatible hydrogel, typically over 30%,, in a photo-tunable and reversible manner, as demonstrated in our preliminary results.
- influence of mechanical stresses on living cells in a 3D imaging set-up, interplay of responsive hydrogel and cell culture in 3D
- the yet unattained level of hydrogel specifications regarding the long-term application to microscopy
- the concept of using a kind of sample holder as a basis for biological tissue manipulation, enabling future development of new observation techniques, all in an all-optical set-up for manipulation and observation
The project will be organized in 4 scientific work packages:
- Synthesis of adequate photochromic dyes which will be responsible of the reversible crosslinking following their shape change.
- Formation of the hydrogels, including optimization by design of experiment procedure
- Physical characterization of the hydrogels by rheology, dynamic light scattering and atomic force microscopy, specifications tests linked to the use in microscopy (transparency, refractive index compatibility...),
- Use of hydrogels as actuators around 3D cell culture for photonic microscopy. This part will examine all links to biology, including cytotoxicity of chemical compounds, and finally confrontation of cardiomyoblasts and cardiomyocytes to the stimulating hydrogel inside the microscopy set-up.
This interdisciplinary project joins together 4 academic laboratories with expertise in material (IMRCP in Toulouse, IMMM in Le Mans), photo-responsive systems (IMRCP), microscopy (ITAV in Toulouse), cell biology (ITAV, I2MC in Toulouse) and clinical sciences (I2MC). The geographic proximity of three partners and the already existing collaborations by pairs of all 4 partners ensures a maximum efficiency for the project.
This project will lead to the development of new visible-responsive hydrogel formulations, which will open applications for soft actuators for biology or responsive drug delivery systems. It will also provide new tools to simultaneously manipulate and observe biological tissue. This is expected to constitute a basis for next generation mechanobiology set-ups with a diversification of the studied pathologies.
Madame Anne-Françoise Mingotaud (LABORATOIRE INTERACTIONS MOLECULAIRES ET REACTIVITE CHIMIQUE ET PHOTOCHIMIQUE)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
IMRCP LABORATOIRE INTERACTIONS MOLECULAIRES ET REACTIVITE CHIMIQUE ET PHOTOCHIMIQUE
IMMM INSTITUT DES MOLÉCULES ET MATÉRIAUX DU MANS
ITAV INSTITUT DES TECHNOLOGIES AVANCEES EN SCIENCES DU VIVANT
I2MC INSTITUT DES MALADIES METABOLIQUES ET CARDIOVASCULAIRES DE TOULOUSE
Help of the ANR 471,031 euros
Beginning and duration of the scientific project: November 2018 - 42 Months