Seminaria Zakładu Biosystemów i Miękkiej Materii

kolor czcionki + kolor tła = plan do 7 dni.

2019-06-28
 plan 
14:00, Sala: S3 im. W. Fiszdona, piętro III
prof. Tony Ladd
University of Florida

Transverse migration of polyelectrolytes in microfluidic channels: Concentrating and purifying DNA?

I will describe recent microfluidics experiments using DNA as a model polyelectrolyte. The DNA is introduced into the channel by a pressure driven flow, and simultaneously subjected to an axial electric field. Epifluorescent and confocal microscopy have been used to show that, under opposing fields, the DNA migrates to the walls of the microfluidic channel. An interesting consequence is that DNA then rapidly accumulates near the channel inlet, suggesting a possible means to both concentrate and purify DNA. Unlike a number of electrokinetic-based separations, the trapping of the DNA does not depend on complex flows orfields. Rather, it exploits (we think) a little studied aspect of polyelectrolytes; namely that an electric field can generate a long-range (1/r 3 ) flow around the molecule. When combined with symmetry breaking, induced (for example) by a shear flow, this leads to novel length-dependent motions of the polymer. In this talk I will summarize the results of our experiments, present the outline of a theory to describe the migration, and suggest possible biotechnology applications.
Tony Ladd, Mert Arca, Ryan Montes and Jason Butler, Unversity of Florida.

2019-06-26
 plan 
12:30, Sala: S3 im. W. Fiszdona, piętro III
dr Marcin Lewandowski
IPPT PAN

MedTech 2020 – how “digital disruption” can impact healthcare

The continuously rising cost of healthcare and an ageing society threaten even the strongest economies. Today, developed countries spend 9% to 12% (USA 17%) of their GDP on this sector.
Medtech is a broad spectrum of product and technologies for medical and healthcare applications, including prevention, diagnosis, monitoring, therapy, and care. We will look at its complex landscape and how "digital disruption" can impact the future of the medical ecosystem and improve the quality of our lives. We will also discuss the increasing role played by digital health and how it could be used in data-driven decision making, shifting the care paradigm from reactive to proactive.
In addition, I will also present my team and our commitment to medical technologies developed at the Institute. Hopefully, a fruitful discussion on current bio-research that might impact the future of Medtech products will conclude my seminar.

2019-06-19
 plan 
12:30, Sala: Aula im. Wacława Olszaka, piętro II
prof. Krzysztof Kuczera
Departments of Chemistry and Molecular Biosciences
University of Kansas

MULTIPLE PATHWAYS OF HELIX FOLDING FROM KINETIC COARSE GRAINED MODELS

Long-term molecular dynamics simulations and a coarse-grained kinetic analysis were carried out to describe the mechanism of formation of an alpha-helical structure. A 12 microsecond molecular dynamics simulation of a 21-residue helix-forming model peptide was generated in explicit solvent, yielding structural and dynamic properties in good agreement with available experimental data. Clustering and optimal dimensionality reduction were applied to produce low-dimensional coarse-grained models of the underlying kinetic network in terms of 2-5 metastable states. In accord with the generally accepted understanding of the multiple conformations and high entropy of the unfolded ensemble of states, the “coil” metastable set contains the largest number of structures. Interestingly, the helix metastable state was also found to be structurally heterogeneous, consisting of the completely helical form and several partly folded conformers which interconvert at a time scale faster that global folding. The intermediate states contain the fewest structures, have lowest populations and have the shortest lifetimes. As the number of considered metastable states increases, more intermediates and more folding paths appear in the coarse-grained models. One of these intermediates corresponds to the transition state for folding, which involves an “off-center” helical region over residues 11-16. The kinetic network model is consistent with a statistical picture of folding following a simple reaction coordinate counting the helical population of individual residues.

2019-05-29 12:30, Sala: S3 im. W. Fiszdona, piętro III
Yasamin Ziai
IPPT PAN

Synthesis and characterization of biocompatible, pH sensitive chitosan-PEG nanoparticles for drug delivery of curcumin used for breast cancer

As the mainstay in the treatment of various cancers, chemotherapy plays a vital role, but still faces many challenges, such as poor tumor selectivity and multidrug resistance. Targeted drug delivery using nanotechnology has provided new strategies which have minimum damage to healthy tissues and maximum release of the drug. Coupling a specific stimuli-triggered drug release mechanism with these delivery systems such as Nanocarriers is one of the most prevalent approaches for improving therapeutic outcomes. Among the various stimuli, pH triggered delivery is regarded as the most general strategy, targeting the acidic extracellular microenvironment and intracellular organelles of solid tumors.
The purpose of my master thesis was to synthesize nanoparticles based on biocompatible chitosan, for drug delivery of curcumin to tissues damaged by breast cancer using pH-triggered delivery. For this purpose, hydrophilicity of chitosan chains were first modified by adding carboxymethyl substitution. In the next step, folate groups were selected to increase tumor targeting in the body as well as enhancing the polymers ability in the process of self-assembly of the nanoparticles, and were grafted into the main chains. One of the characteristics of cancerous tissues is the acidity of pH, which can be used as a stimulant for targeted drug delivery. To create pH-sensitive acetal bonds on carboxymethyl chitosan folate chains, in the first step, amino groups of these chains were protected using phethalic anhydride and then methoxy-polyethylene glycol containing aldehyde groups at one end of their chains (mPEG-Aldehyde) were bonded to carboxymethyl-free hydroxyl groups, and at the final step the phethalic anhydride groups were de-attached using sodium hydrobutyrate (NaBH4). At each stage, the synthesis and structure of the obtained polymers were verified using the FT-IR and H-NMR tests. In the last step of this study, drug containing nanoparticles were made and these nanoparticles, were examined by DLS, SEM and then, using the UV-Vis, the amount of drug loaded in these nanocomposites was obtained and finally, drug release profile is obtained. The system was tested in two pH conditions (e.g. 7.4 and 4.8). The results of this test indicate an increase in the release rate of the drug in the acidic environment.

2019-05-22 14:00, Sala: S5 im. L. Filipczyńskiego, piętro V
Dr. Maciej Lisicki
Insitute of Theoretical Physics, Faculty of Physics
University of Warsaw

Pumping and swimming: two faces of phoretic flows

Janus particles with the ability to move phoretically in self-generated chemical concentration gradients are model systems for active matter. On the other hand, chemically active surfaces can lead to microscale flow generation, becoming an effective pumping mechanism in inertia-less small-scale flows. In this talk, after a broad review of the physics and biology of microswimmers, I will review briefly both phenomena relating to the same concept of phoretic flow generation. Asymmetry needed for the flow to be initiated can be induced by geometry or by chemical patterning. I will show examples of both ways and some applications in biomimetic systems of fully three-dimensional phoretic swimmers.

ArchiwumSeminaria 1996-2010
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