As the title says, I will try to tell you a bit about our work dedicated to PEC lipids

with the AUC.

But I would love to start with a bit of motivation.

So if you heard already in the previous sessions that currently gen delivery strategies for

medicine is quite a hot topic and one of the way to do it is to use lipid nanoparticles

and briefly how these lipid nanoparticles are working.

So first lipid nanoparticles bring encasolated mRNA into the cell, it goes into the cell,

all the protection mechanisms, release mRNA and then this mRNA do all the job to produce

spike proteins and then these spike proteins trying to produce antibodies.

But if we have a look a bit deeper into the lipid nanoparticle structure, it consists of

a lot different parts.

So ionizable lipid helper lipid holosterol, it's mostly used for stability of the nanoparticle

to encapsulate genetic material.

So mRNA is our targeted cargo but we also have the polymer lipid which is quite small

amount of overall particle volume and this polymer lipid dictates the size of the nanoparticle,

its data potential and moreover it's supposed to have some stealth effects to increase the

circulation time of our particle inside the blood stream.

So this polymer lipid mostly used as a PEC lipid and this is a two commercially available

PEC lipids that were used in the recent mRNA vaccine against SARS-CoV-19 and people in

the whole world really like to use PECs but what happened?

So excessive use of PEC in everyday products like creams, medicine and so on raised a new

challenge, so called PEC antibodies and more and more publications report this issue.

But why it's bad?

So of course the first thing it will reduce circulation time so the body will try to attack

PEC and to remove it from the organism so it will reduce efficiency of the treatment.

Moreover in the really worst case it will lead to occurring some allergies and we want

to avoid it.

That's why a lot of work was dedicated already to find some alternatives to the PEC.

One of these is polyethylene oxazoline which were quite excessive study with AUC and all

the other related techniques in our group and what we found in the studies that hydrodynamically

from these Mark-Kun-Havings-Sakurada scaling relationships it behaves quite similar to

PEC.

But there is no study dedicated to PEC lipid conjugates itself, themselves, so together.

And that's why where we come in.

So we want to study this PEC lipids by the methods of hydrodynamics meaning that we use

analytical intensification, viscometry, viscometric studies, densimetric studies.

As well we do some support studies with the light scattering meaning dynamic light scattering

and the most powerful thing, one of the most powerful thing is also microscopy that allows

us to get into, to have a look at what system we have inside.

So first I will show you the hydrodynamic investigation of the viscosity and density

of the material.

So when we put our PEC lipids into the ethanol we find out a typical linear scaling, not

scaling extrapolation of Huggins and Kramer extrapolation procedures which indicates that

the polymer behave like a random coil.

Moreover if we then have a look at the interesting viscosity values we see that it's quite small

value of this parameter which is quite expected for the low molar mass polymer.

Yes, Huggins constant and Kramer constants are not really nice but this is because ethanol

is not really good solvent for the PEC chain or the PEC lipid but still it shows that it

works fine and the partial specific volume determined from the density increment measurements

have shown that we have increased value of this parameter which means that the lipid