Soft & Biological Matter Session

Soft & Biological Matter Session

Soft & Biological Matter Session

 

Chair: Nadav Amdursky (Technion)

 

13:30-13:50

Uri Raviv (HUJI)
Keynote Speaker

Title:
Mechanism of Virus Capsid Assembly

Abstract:
There is a huge number of possible intermediates on the assembly path from hepatitis B capsid protein dimers to 120-dimer capsid. If every intermediate were tested, assembly would often get stuck for entropic reasons and essentially every capsid would follow a unique assembly path. Yet, capsids assemble rapidly with minimal trapped intermediates. To understand the fundamental mechanisms of capsid assembly it is critical to resolve the early stages of the reaction. To observe assembly, we used time-resolved Small Angle X-ray Scattering, which is sensitive to solute size and shape and has millisecond temporal resolution. Scattering curves were fit to a thermodynamically curated library of assembly intermediates, using a maximum information entropy approach to provide a physical rationale for the selection of intermediates. We found that capsid assembly was controlled by the supersaturation state of the system at the onset of assembly, dictating the intermediate structures during the early stages of the reaction. With the mildest conditions tested, we observed a nearly two-state reaction from dimer to capsid with a small number of dimers-of-dimers and trimers-of-dimers. In slightly more aggressive conditions, we observed a decamer-of-dimers and a 90-dimer species. In conditions where there is measurable kinetic trapping, we found a greater diversity of early intermediates, accumulated within a fraction of a second and propagated into long-lived kinetically trapped states (>90-mer). In all cases, intermediates >30 and <90 subunits did not accumulate. These results indicate the presence of low barrier paths that connect intermediates that can direct the ultimate assembly path to late intermediates where assembly can be paused.

 

13:50-14:05

Boaz Mizrahi (Technion)
Invited Speaker

Title:
Multi-Armed Polymers as Tissue Adhesives: Fundamentals to Applications

Abstract:
Multi-armed polymers, often termed star polymers, are highly branched macromolecules with three-dimensional architectures. Each molecule is composed of a central core from which linear arms emanate. Star polymers have a number of chemical and physical properties (e.g. their solubility and low melting point) that make them useful in several biomedical fields, from drug-delivery, tissue adhesives to tissue engineering and coatings. While solid polymers with high molecular weights (>5000 Da) are receiving significant attention in polymer science, the development of liquid star polymers remains relatively unexplored. I will discuss new concepts and strategies and present some bio-adhesion applications based on the unique structure of soft- star polymers.

 

14:05-14:15

Irit Rosenhek-Goldian (WIS)
Contributed Speaker

Title:
AFM for biophysical characterization of soft matter: from extracellular vesicles to cells and tissues

Abstract:
In atomic force microscopy (AFM) the surface is probed by a tip attached to a cantilever (spring) that can measure the surface topography along with biophysical properties like stiffness, adhesion and viscoelasticity. AFM enables gentle scanning of soft biological samples, under physiological buffer solutions to mimic the natural environment. It is applicable to a large variety of samples at various length scales, from tiny extracellular vesicles (EVs), through cells to whole tissue. However, each study represents a new set of considerations, requiring custom-tuned experimental design to ensure meaningful results. For example, the sample preparation step is critical in terms of purity and robust attachment of the object of interest to the surface. The choice of cantilever, scanning conditions, and measurement procedure are important to enable proper, stable and gentle measurement. 
In this presentation these issues will be discussed, based on our hands-on experience with 3 different projects applying AFM to study of soft biological samples: imaging of malaria-derived EVs, imaging and stiffness measurements on red blood cells, and viscoelasticity measurements on colon tissue. Each measurement will be presented along with the strategic approach employed and how the complications encountered were overcome.

 

14:15-14:25

Esti Toledo (BGU)
Contributed Speaker

Title:
Molecular Scale Spatio-Chemical Control of the Activating-Inhibitory Signal Integration in NK Cells

Abstract:
Innate immune system is based on natural killer (NK) cells – lymphocytes that distinguish between healthy and diseased cells, and attack tumor. The activity of NK cells regulate through a delicate balance between activating and inhibitory signals delivered by a multitude of activating and inhibitory receptors. The role of juxtaposition of activating and inhibitory receptors in signal inhibition of cytotoxic lymphocytes remains strongly debated. The challenge lies in the lack of tools that allow simultaneous spatial manipulation of signaling molecules. Recently, biomimetic devices that control spatial organization of receptors within the cell membrane have been extensively used to study how the receptor spatial order regulates cell function, including that of immune lymphocytes. These devices comprise of lithographically patterned nanodots functionalized with cognate ligands for the studied receptors. Yet, these devices have been limited to control only receptor of one type, and thus could not be used to study signal integration between different receptors.
To circumvent this, we produced a nanoengineered multifunctional platform with molecular scale spatial control of ligands, which was applied to elucidate KIR2DL1-mediated inhibition of NKG2D signalling receptors of natural killer cells. This platform was conceived by bimetallic nanodot patterning with molecular-scale registry, followed by a ternary functionalization with distinct moieties. We found that a 40-nm gap between activating and inhibitory ligands provided optimal inhibitory conditions. Supported by theoretical modelling, we interpret these findings because of the size mismatch and conformational flexibility of ligands in their spatial interaction. This highly versatile approach provides an important insight into the spatial mechanism of inhibitory immune checkpoints, which is essential for the rational design of future immunotherapies.

 

14:25-14:40

Alireza Dolatshahi-Pirouz (DTU, Denmark)
Invited Speaker

Title:
Human-adaptable cyborg-like biomaterial sensors for healthcare monitoring

Abstract:
Historically the field of biomaterials science has primarily focused on assuring biocompatibility between materials and humans. Less effort has been directed towards transforming biomaterials into life-like entities with the capacity for continuously adapting to our dynamic body and tissues. Most conventional medical devices, are actually still in disharmony with biological systems, which are in a never-ending progress of adaption and evolution. The central theme behind our research is mitigating a new avenue into this hitherto uncharted territory by developing an innovative class of materials that can become 3D printed into custom-adaptable medical devices capable of reconfiguring in response to dynamic environments, while simultaneously enabling real-time monitoring of important biological events. Notably, our proposed monitoring platform is multifunctional and based on a simple, cheap and scalable approach. Biomaterials that can reconfigure and adapt in response to dynamic stimuli is indeed an emerging concept that ultimately could change medical devices from being a foreign foe to a fully integrated part of us.

 

14:40-15:00

Molly Stevens (ICL, London)
Keynote Speaker

Title:
Designing the bio-material interface for biomedical applications

Abstract:
This talk will provide an overview of our recent developments in bio-instructive, self-assembling and gradient materials for applications in regenerative medicine with focus on establishing translational pipelines to bring our innovations to the clinic [1]. I will discuss recent developments in our tunable nanoneedle arrays for multiplexed intracellular biosensing at sub-cellular resolution and modulation of biological processes [2] and will talk about our portfolio of nanoparticle-based sensing probes for disease monitoring in vivo such as renal clearable gold nanoclusters for cancer detection [3]. We integrate our nanomaterial-based assays into smartphone enabled tests for point-of-care cancer diagnostics and monitoring of disease progression and response to treatment [4]. Finally, I will present our advances in Raman spectroscopy characterisation techniques for high-throughput label-free characterization of single nanoparticles (SPARTA®) which is becoming an integral tool for the design of advanced nanotherapeutics [5]. I will explore how these versatile technologies can be applied to transformative biomedical innovations.

[1] J. P. K. Armstrong… M. M. Stevens. “A blueprint for translational regenerative medicine.” Science Translational Medicine. 2020. 12(572): eaaz2253.
[2] C. Chiappini… M. M. Stevens, E. Tasciotti. “Biodegradable silicon nanoneedles delivering nucleic acids intracellularly induce localized in vivo neovascularization.” Nature Materials. 2015. 14: 532
[3] C. N. Loynachan… M. M. Stevens. “Renal clearable catalytic gold nanoclusters for in vivo disease monitoring.” Nature Nanotechnology. 2019. 14: 883–890.
[4] C. S. Wood, … M. M. Stevens. “Taking connected mobile-health diagnostics of infectious diseases to the field.” Nature. 2019. 566: 467-474.
[5] J. Penders… M. Stevens. “Single particle automated Raman trapping analysis.” Nature Communications. 2018, 9: 4256.

 

15:00-15:20

Roundtable Discussions

 

Bioderived Materials for Health Applications: Current challenges and opportunities


Moderator: Nadav Amdursky

 
 

Our Sponsors

SAVE THE DATE

IVS-IPSTA 2021 - 39th Annual Conference
November 17, 2021 | ONLINE

Conference Organizing Team


Gilbert Daniel Nessim (IVS President, BIU) | Ilya Grinberg (BIU) | Haim Barak (BIU)

Tatyana Bendikov (WIS) | Elad Koren (Technion) | Muhammad Bashouti (BGU) 
Noa Lachman-Senesh (TAU) | Igal Kronhaus (Technion)
Sharon Waichman (NRCN, Rotem Industries)