National Science Centre has approved and subsidized four projects from IPPT PAN:

I. OPUS 15 (research proposals submitted under this funding scheme may include the purchase or construction of research equipment)

  • „Coordination of innate immune response in infected cell population: experiment and mathematical modeling”

Project coordinator: prof. dr hab. Tomasz Lipniacki.

Innate immune responses form the first line of defense against invading pathogens; it may eradicate pathogens or slow down progression of infection allowing adaptive immune responses to develop. We are used to think about immune response after getting sick, while the main task of innate immunity is to prevent development of infection, before we even notice it. Our lungs are in frequent contact with viruses, and potential infections can start from a very few infected cells. These cells may attempt to resist viral multiplication themselves, but more importantly they should try to inform other cells about the threat. Cell-to-cell communication is enabled by various cytokines, that is, proteins that are secreted by cells and activate specific programs in neighboring cells in the tissue. Cytokine-alarmed cells increase levels of numerous antiviral proteins and become more resistant to infection, but to have their protective effect the cytokines have to reach these cells hours before the replicating virus. The competition between immune response and viral spread gives rise to temporal subpopulations of cells: infected/uninfected, cytokine-secreting or not, suppressing multiplication of virus or “allowing” virus to replicate. The aim of our study is to characterize these subpopulations, their communication by cytokines and their role in limiting the spread of the virus. In order to enable cytokine communication, cells have to allow for protein synthesis; however, to suppress multiplication of virus cells should inhibit protein synthesis and degrade viral genetic material. The specific question we aim to answer is how the cell population is able to reconcile these two contradictory functional programs.
We will work with two respiratory viruses: influenza virus and respiratory syncytial virus. Both viruses are responsible for life-threatening conditions such as bronchiolitis and pneumonia, and are a major cause of death among young children and the elderly. Unsurprisingly, both viruses have been intensively studied. Most studies however were performed either in animals (which makes the analysis of intracellular processes difficult) or at non-physiologically high levels of infecting viruses when majority of cells are infected and thus the immune responses cannot develop at the cell-population level. We expect that our studies will help to elucidate mechanisms of innate immune responses critical for preventing infections.

  • „New computational approaches for modelling of sharp and diffuse interfaces”

Project coordinator: prof. dr hab. Stanisław Stupkiewicz.

Practically all engineering materials contain interfaces such as interfaces separating the constituents in composite materials, grain boundaries in polycrystalline materials, phase boudaries accompanying phase transformations, and others. Importantly, the interfaces substantially influence the material behaviour, hence accurate modelling of the interfaces, including adequate representation of the interfaces in computational methods, is crucial for reliable modelling of the materials and, in particular, for gaining an improved understanding of the role of the interfaces. In some situations, for instance, during phase transformations, the interfaces may evolve, i.e. nucleate, propagate and annihilate, which gives rise to various interesting phenomena, but also makes the corresponding modelling more difficult. The main goal of the present project is to develop new approaches and new computational strategies for the modelling of both non-propagating and propagating interfaces. A specific class of approaches will be considered in which the discretization introduced to numerically solve the problem does not match the geometry of the interfaces. This approach offers significant advantages, however, it also has a substantial disadvantage due to the additional approximation error introduced. The aim will thus be to reduce the related error, while keeping the advantages of the approach.
The improved computational schemes developed within the project will next be applied to solve selected problems of great interest in materials science. Three advanced materials, in which evolving interfaces play a particularly important role, have been selected for the study. The first material is the polycrystalline NiTi shape memory alloy (SMA). It has been observed experimentally that the martensitic transformation, which is the actual mechanism of inelastic deformation in SMAs, is often not homogeneous, but rather it proceeds through nucleation and propagation of macroscopic phase transformation fronts. The goal will be to study the structure of the macroscopic phase transformation fronts and to explain the mechanisms responsible for the inhomogeneous deformation. The second class of materials includes magnesium alloys in which plastic deformation involves an additional mechanism called deformation twinning. Twinning is a kind of displacive transformation that proceeds through nucleation and propagation of twinning planes. The physical mechanism of special interest is the reverse mode of twinning, in particular, the pseudo-reverse mode of twinning which has been recently demonstrated experimentally and which will be addressed in the present project. As the third material system, the layered structure of lithium-ion batteries has been selected. In this material, the phenomenon of interest in this project is the damage and fracture in the condition of mechanical abuse. This aspect is crucial for the safety of the batteries used for the propulsion energy storage in automotive applications, as even moderate mechanical impacts may lead to internal damage, short-circuit and fire hazard.

II. PRELUDIUM 15 (pre-doctoral grants)

  • „Thermosensitive hydrogels filled with bioactive nanofibers for regeneration of neural tissue”

Project coordinator: Beata Niemczyk.

The objective of the project is to design a smart injectable material for native neural tissue engineering applications. Composition and fabrication process should provide material properties, which on the one hand assure injectability and on the other, after injection, mimic the neural extracellular matrix (ECM). The neural ECM is characterized by low mechanical stiffness and 3D oriented structure. In order to accomplish the objective, it is proposed to use hydrogel, methylcellulose (MC) aqueous solution, which cross-links near the physiological temperature. Another component is agarose aqueous solution, which is expected to increase the stiffness of MC and to affect kinetics of MC cross-linking. In order to provide, both, orientation of the final structure and injectability, addition of short bioactive nanofibers is proposed. Here, poly-L-lactide (PLLA) and laminin will be electrospun and further fragmented into short fibers by ultrasonication.

  • „Development of novel methods for measuring viscosity and interfacial tension of liquids using microfluidic devices”

Project coordinator: Damian Zaremba.

The aim of the project is to examine the phenomena and explain the basic mechanisms responsible for the behaviour of liquids in closed microfluidic systems. This will allow the development of measurement methods to detect slight changes in physicochemical properties such as viscosity and interfacial tension in small samples with a volume of the order of nano- and microliters. Methods for single-phase(viscosity) and two-phase(viscosity and interfacial tension) flows will be developed. Systems using these methods will be used primarily in the construction of more complex microfluidic devices called Lab-on-Chip used for biochemical research and in the study of complex fluids.