Periodic Reporting for period 4 - MetamorphChip (Dynamic Microfluidic Structures for Analysis of Single Cell Systems)
Okres sprawozdawczy: 2020-10-01 do 2021-03-31
The interaction and communication between individual cells plays a central role in virtually all fields of biology, from the cooperative work of cells in the immune system, through the differentiation of stem cells, and to the proliferation of cancer cells. In recent years it has been shown that these processes are fundamentally coupled to cell-to-cell heterogeneity and variability, which manifests itself in all cell functions, from the level of the genome, transcriptome, and proteome, to the level of proliferation, migration, differentiation and apoptosis. Studying cellular ensembles masks these differences, and may yield observations that are not representative of any individual cell type or subpopulation. Despite this, most current studies consider cell populations, largely due to technological limitations in the ability to dynamically compartmentalize, manipulate, and analyze single cells. Gaining further insight into the role of heterogeneity at the single cell level is an essential step towards developing new therapeutic approaches. Progress in this field requires a significantly improved ability to access and study cellular interaction at the single cell level, and to support quantitative modeling of such processes.
In the past decade, there has been considerable development in high-throughput methods of single-cell analysis. Tools developed include various microfluidic chips for individual or paired cell capture and analysis, droplet microfluidics, digital microfluidics, FACS and microFACS. Particularly notable is the use of on-chip pneumatic valves enabling elaborate multi-step protocols to be performed. These tools have reduced time necessary for hands-on work, and allowed for work at previously unattainable single-cell scales, enabling fundamental discoveries in all aspects of biology. However, despite these advantages, many of the high-throughput single cell analysis technologies are still single-purpose “protocols on chips” rather than true “labs on chips”: they do not allow the flexibility and real-time experimental decision-making essential to scientific work. After carrying out a predetermined protocol, it is rarely possible to perform unplanned follow-up experiments on the same cells or on the same system, based on the obtained results. Rapid progress in research depends on the ability to make real-time experimental decisions, in which the observations from the current step direct subsequent steps in the experiment – a level of flexibility unattainable with current tools.
In this project we aim to develop a new concept for a single-cell-level bioanalytical workspace that is dynamically configurable in real time. By using electrokinetically driven surface deformations, microfluidic structures may be created or destroyed in real-time allowing cells to be introduced, separated, reunited, or removed, and liquids to be selectively introduced to, removed from, or moved between specific cells, either based on a predetermined program or more importantly – on demand (by the researcher, or an image processing algorithm), based on the state of the experiment at any time point. This workspace will be implemented in a microfluidic chip format, which we term the MetamorphChip.
In the past decade, there has been considerable development in high-throughput methods of single-cell analysis. Tools developed include various microfluidic chips for individual or paired cell capture and analysis, droplet microfluidics, digital microfluidics, FACS and microFACS. Particularly notable is the use of on-chip pneumatic valves enabling elaborate multi-step protocols to be performed. These tools have reduced time necessary for hands-on work, and allowed for work at previously unattainable single-cell scales, enabling fundamental discoveries in all aspects of biology. However, despite these advantages, many of the high-throughput single cell analysis technologies are still single-purpose “protocols on chips” rather than true “labs on chips”: they do not allow the flexibility and real-time experimental decision-making essential to scientific work. After carrying out a predetermined protocol, it is rarely possible to perform unplanned follow-up experiments on the same cells or on the same system, based on the obtained results. Rapid progress in research depends on the ability to make real-time experimental decisions, in which the observations from the current step direct subsequent steps in the experiment – a level of flexibility unattainable with current tools.
In this project we aim to develop a new concept for a single-cell-level bioanalytical workspace that is dynamically configurable in real time. By using electrokinetically driven surface deformations, microfluidic structures may be created or destroyed in real-time allowing cells to be introduced, separated, reunited, or removed, and liquids to be selectively introduced to, removed from, or moved between specific cells, either based on a predetermined program or more importantly – on demand (by the researcher, or an image processing algorithm), based on the state of the experiment at any time point. This workspace will be implemented in a microfluidic chip format, which we term the MetamorphChip.
- We developed complete models for deformations of elastic sheets using electroomostic forces. The models have been generalized to allow introduction of alternative forces, and we have complete analytical and numerical solutions allowing us to design and predict deformation states. The work has been published in four peer-reviewed publications in the very best journals in the field of fluid mechanics (4 publications in JFM and PRF).
- We experimentally demonstrated the ability to pattern flows and pressure fields at the microscale by controlling the spatial surface charge chemically and electrically. This work has been published in two peer-reviewed publications in top journals (2 publications in PRL and PNAS).
- This also led to an unexpected result where we showed, in collaboration with Prof. Steffen Hardt's group at TU Darmstadt, that electroosmosis can be used to cloack and shield objects in microscale flows. This was published in PRL and received the Editors’ selection.
- We discovered and reported the existence of a fluid–structure instability arising from the interaction of electro-osmotic flow with an elastic substrate. We reported the physical mechanism in PRL and a more in-depth analysis for elastic sheets in PRF.
- Based on the physical mechanisms developed, we presented a new concept for on-chip bioanalysis of molecules and particles. This work was published in one of the best chemistry journals (Angewandte Chemie) and received the designation of a very important paper.
- We also investigated other mechanisms for controlling flows at the microscale and for creating desired spatial deformations. One study was on thermocapillary flows, which was published in PRF. An unexpected result from that study was a mechanism for actuating microswimmers using photoactuation. In followup work now under consideration, we demonstrate the ability to create any desired deformation by projection of light which drives temperature gradients and subsequent deformation. Another study was based on dielectrophoresis, and is currently under review in FLOW.
- Our work for elastic deformations and the need to measure the deformation of these surfaces triggered a collaboration with Prof. Yoav Shechtman’s group at Technion on a new method for profiling spatial deformations. The work was published in Science Advances.
Finally, experimenting with liquid-liquid interfaces, we realized that the use of an immersion liquid can overcome the capillary length restriction. Furthermore, we found that simply controlling geometrical boundary conditions of a system, without any actuation, is a very powerful and robust method for manipulating the liquid and controlling its shape and which, to the best of our knowledge, was never explored neither in the fluid mechanics community nor in the manufacturing community. This was an unexpected result, which was selected as the inaugural paper of the new journal Flow (Cambridge University Press) dedicated to applications of fluid mechanics:
- We experimentally demonstrated the ability to pattern flows and pressure fields at the microscale by controlling the spatial surface charge chemically and electrically. This work has been published in two peer-reviewed publications in top journals (2 publications in PRL and PNAS).
- This also led to an unexpected result where we showed, in collaboration with Prof. Steffen Hardt's group at TU Darmstadt, that electroosmosis can be used to cloack and shield objects in microscale flows. This was published in PRL and received the Editors’ selection.
- We discovered and reported the existence of a fluid–structure instability arising from the interaction of electro-osmotic flow with an elastic substrate. We reported the physical mechanism in PRL and a more in-depth analysis for elastic sheets in PRF.
- Based on the physical mechanisms developed, we presented a new concept for on-chip bioanalysis of molecules and particles. This work was published in one of the best chemistry journals (Angewandte Chemie) and received the designation of a very important paper.
- We also investigated other mechanisms for controlling flows at the microscale and for creating desired spatial deformations. One study was on thermocapillary flows, which was published in PRF. An unexpected result from that study was a mechanism for actuating microswimmers using photoactuation. In followup work now under consideration, we demonstrate the ability to create any desired deformation by projection of light which drives temperature gradients and subsequent deformation. Another study was based on dielectrophoresis, and is currently under review in FLOW.
- Our work for elastic deformations and the need to measure the deformation of these surfaces triggered a collaboration with Prof. Yoav Shechtman’s group at Technion on a new method for profiling spatial deformations. The work was published in Science Advances.
Finally, experimenting with liquid-liquid interfaces, we realized that the use of an immersion liquid can overcome the capillary length restriction. Furthermore, we found that simply controlling geometrical boundary conditions of a system, without any actuation, is a very powerful and robust method for manipulating the liquid and controlling its shape and which, to the best of our knowledge, was never explored neither in the fluid mechanics community nor in the manufacturing community. This was an unexpected result, which was selected as the inaugural paper of the new journal Flow (Cambridge University Press) dedicated to applications of fluid mechanics:
All of our work done to date goes beyond the state of the art, and was published in leading peer-reviewed journals.
Since this is the final report, there are not additional results expected with the scope of the project.
Since this is the final report, there are not additional results expected with the scope of the project.