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A Combinatorial Library of Lipid Nanoparticles for RNA Delivery to Leukocytes
Ramishetti, S., Hazan‐Halevy, I., Palakuri, R., Chatterjee, S., Naidu Gonna, S., Dammes, N., Freilich, I., Kolik Shmuel, L.,  Danino, D., Peer, D. Advanced Materials 32 (12), 1906128 (2020)

Lipid nanoparticles (LNPs) are the most advanced nonviral platforms for small interfering RNA (siRNA) delivery that are clinically approved. These LNPs, based on ionizable lipids, are found in the liver and are now gaining much attention in the field of RNA therapeutics. The previous generation of ionizable lipids varies in linker moieties, which greatly influences in vivo gene silencing efficiency. Here novel ionizable amino lipids based on the linker moieties such as hydrazine, hydroxylamine, and ethanolamine are designed and synthesized. These lipids are formulated into LNPs and screened for their efficiency to deliver siRNAs into leukocytes, which are among the hardest to transfect cell types. Two potent lipids based on their in vitro gene silencing efficiencies are also identified. These lipids are further evaluated for their biodistribution profile, efficient gene silencing, liver toxicity, and potential immune activation in mice. A robust gene silencing is also found in primary lymphocytes when one of these lipids is formulated into LNPs with a pan leukocyte selective targeting agent (β7 integrin). Taken together, these lipids have the potential to open new avenues in delivering RNAs into leukocytes.

Advanced Materials graphical abstract

 

 

 

 

 

 

 

 

 

Physico‐chemical properties of LNPs made from different ionizable lipids (lipids 1–14). a) LNPs mean diameter and PDI; b) zeta potential measured by Zeta Sizer; c) cryo‐TEM analysis of lipid‐8‐ and lipid‐10‐based LNPs.


Shape and fluctuations of frustrated self-assembled nano ribbons
Zhang, M., Grossman, D., Danino, D., and Sharon, E. Nat Commun10(1):1-7 (2019)

Self-assembly is an important process by which nontrivial structures are formed on the sub-micron scales. Such processes are governed by chemical and physical principles that dictate how the molecular interactions affect the supramolecular geometry. Currently there is no general framework that links between molecular properties and the supramolecular morphology with its size parameters. Here we introduce a new paradigm for the description and analysis of supramolecular structures that self-assemble via short-range interactions. Analysis of molecular interactions determines inputs to the theory of incompatible elasticity, which provides analytic expressions for supramolecular shape and fluctuations. We derive quantitative predictions for specific amphiphiles that self-assembled into chiral nanoribbons. These are quantitatively confirmed experimentally, revealing unique shape evolution, unusual mechanics and statistics, proving that the assemblies are geometrically incompatible. The success in predicting equilibrium and statistics suggests the approach as a new framework for quantitative study of a large variety of self-assembled nanostructures.graphical abstract Nat Commun

 

 

 

 

 

 

Shape evolution and characterization: Cryo-TEM images and illustrations (insets) of self-assembled N- α -lauryl-lysyl-aminolauryl-lysyl-amide (C1212) ribbons. a After ~24 h of assembly most ribbons are twisted, having a straight centerline, (inset, yellow dashed line) i.e. R = 0. b After 1 week, helical ribbons are abundant. Their center line is a helix with given pitch, P, and radius, R. Determination of W, P, and R from the image is demonstrated. c After 5 months most assemblies are tubes (distinguished by the dark parallel boundaries compared to the pale ends) with diameters D = 2 R ≈ 100 nm. Scale bars = 100 nm


Role of proton balance in formation of self-assembled chitosan nanoparticles
Dey, A., Kamat, A., Nayak, S., Danino, D., Kesselman, E., Dandekar, P. and Jain, R. Colloids Surf B Biointerfaces, 166:127-134 (2018)

Researchers have explored the ability of chitosan to form nanoparticles, to suit varying applications, ranging from wound-healing to gene delivery. Ionic gelation is a widely used method for formulating chitosan nanoparticles, where self-assembly plays a crucial role. This self-assembly is initially promoted by hydrophilic-hydrophobic parity amongst individual chitosan residues, along with electrostatic and Van der Waals interactions with the cross-linker. However, until now the intrinsic ability of chitosan to self-assemble is not widely studied; hence, we investigate the self-assembly of chitosan, based on proton balance between its protonated and deprotonated residues, to promote facile nanoparticle synthesis. This is one of the first reports that highlights subtle but critical influence of proton balance in the chitosan polymer on the formation of chitosan nanoparticles.

Effect of pH on chitosan nanoprticles


Viscosity Peak due to Shape Transition from Wormlike to Disklike Micelles: Effect of Dodecanoic Acid

Anachkov, S.E., Georgieva, G.S., Abezgauz, L., Danino, D. and Kralchevsky, P.A. Langmuir, 34(16):4897-4907 (2018)

Here, we have investigated the synergistic growth of long wormlike micelles and their transformation into disklike micelles, which occurs in three-component solutionscomposed of sodium lauryl ether sulfate (SLES; anionic), cocamidopropyl betaine (CAPB; zwitterionic), and dodecanoic acid (HC12; nonionic). The solution rheology is characterized in terms of zero-shear viscosities and characteristic times for micellar breaking and reptation. Furthermore, the microstructure evolution, leading to the observed rheological behavior, is revealed by cryo-transmission electron microscopy (TEM) micrographs. In all cases, the CAPB-toSLES ratio is fixed, whereas the fatty acid concentration is varied. At a certain HC12 concentration, the solution viscosity passes through a maximum. The cryo-TEM imaging indicates that wormlike micelles appear before the peak, grow further up to the peak, and finally transform into disklike aggregates (a very rare micellar structure) after the peak. The transformation of worms into disks leads to a drop in viscosity because the length-to-thickness aspect ratio of the disks is significantly lower than that of the worms. In this article, we elucidate the structure−rheology relations in micellar solutions that might be applied for the design of personal-care and household formulations.

Transition of wormlike to disklike micelles by dodecanoic acid


Ferritin is secreted via 2 distinct nonclassical vesicular pathways

Truman-Rosentsvit, M., Berenbaum, D., Spektor, L., Cohen, L.A., Belizowsky-Moshe, S., Lifshitz, L., Ma, J., Li, W., Kesselman, E., Abutbul-Ionita, I., Danino, D., Gutierrez, L., Li, H., Li, K., Lou, H., Regoni, M., Poli, M., Glaser, F., Rouault, T.A. and Meyron-Holtz, E.G. Blood, 131(3):342-352 (2018)

Ferritin turnover plays a major role in tissue iron homeostasis, and ferritin malfunction is associated with impaired iron homeostasis and neurodegenerative diseases. In most eukaryotes, ferritin is considered an intracellular protein that stores iron in a nontoxic and bioavailable form. In insects, ferritin is a classically secreted protein and plays a major role in systemic iron distribution. Mammalian ferritin lacks the signal peptide for classical endoplasmic reticulum–Golgi secretion but is found in serum and is secreted via a nonclassical lysosomal secretion pathway. This study applied bioinformatics and biochemical tools, alongside a protein trafficking mouse models, to characterize the mechanisms of ferritin secretion. Ferritin trafficking via the classical secretion pathway was ruled out, and a 2:1 distribution of intracellular ferritin between membrane-bound compartments and the cytosol was observed, suggesting a role for ferritin in the vesicular compartments of the cell. Focusing on nonclassical secretion, we analyzed mouse models of impaired endolysosomal trafficking and found that ferritin secretion was decreased by a BLOC-1 mutation but increased by BLOC-2, BLOC-3, and Rab27A mutations of the cellular trafficking machinery, suggesting multiple export routes. A 13-amino-acid motif unique to ferritins that lack the secretion signal peptide was identified on the BC-loop of both subunits and plays a role in the regulation of ferritin secretion. Finally, we provide evidence that secretion of iron-rich ferritin was mediated via the multivesicular body–exosome pathway. These results enhance our understanding of the mechanism of ferritin secretion, which is an important piece in the puzzle of tissue iron homeostasis.

A 13 amino acid motif on both ferritin subunits is involved in ferritin secretion

Congratulations

Materna Technion magazin

 

 

Winning one of four research grants from Materna Institute on “Following Structure Formation During the Digestion of Infant Formula by Cryo-TEM”

 

 

 

 

 

 

 

 

 

 

 


Luba Kolik receiving Litan Price

Luba Kolik receiving the Litan Prize, with Litan family and dean Prof. Yuval Shoham of Biotechnology and Food Engineering faculty .

 

Inbar Elazar receiving Chairman award for excellence

Inbar Elazar receiving Chairman award for excellence, with the Technion Chairman – Prof. Peretz Lavie.

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