A key factor in the utilization of the proposed nano-carriers is their pore size distribution. Is it necessary to determined pore size in nano particles? Or how can I determine the pore size of the particles? I synthesized chitosan-PEG nano particle (40nm) and took TEM but I couldn't see any pore in them.
I mean that is it necessary to determine pore size of nanoparticles in drug delivery and drug release? Why I cannot find any report about pore size of nano carrier which used in drug delivery?
is there any other ways for the size determination, since facilties for SAXS are not avalable
If you fill the pores with some fluid you may be able to see the size with wide line NMR in the relaxation times.
Vishnu : I think u can go for a simple particle size analyzer by malvern company and also SEM to find the surface morphology.
Dear Narasimhan Kumar,
would you please give more more information about Particle analyzer. I got DLS so how can I measure the pore size? about SEM it is not possible because the particles have small size about 40 nm and its not possible to determined the pore size with SEM.
Dear Lin
BET measure the porosity and mention the volume of pores . I think that it cannot measured the pore size. by the way I am not sure about it. would you please give me more information about it?
Dear Ahmed
would you please explain how can I get pore volume, pore diameter and area from bet?
BET Sorptometer accurately measures properties such as:
-total surface area (via single and multi-point methods)
-adsorption and desorption isotherms
-mean pore size
-pore size distribution
-pore volume, and pore structure.
Monolayer formation of gas molecules on the surface is used to determine the specific surface area, while the principle of capillary condensation can be applied to assess the presence of pores, pore volume and pore size distribution. Prior to the measurement, the sample is pre-treated at elevated temperature in vacuum or flowing gas in order to remove any contaminants.
In general, two different techniques can be distinguished:
-The flow technique uses a TCD detector to obtain information on the amount of adsorbed gas resulting in a specific BET surface area and/or total pore volume.
-The volumetric technique provides more information, since many adsorption and/or desorption points are measured providing a full isotherm with information on BET surface area, pore volume and pore size distribution.
I think this method can determine the pore size distribution of Macro and Mesoporous materials (>2nm).
But I think you might have seen the pores by TEM although it was not possible to evaluate accurately the pore size distribution.
In the case of nanoparticle, determining the pore size distribution depends on the application of particles.
In the case of drug delivery, if you gonna use these nanoparticle to adsorb drug and release it gradually, of course, pore size distribution will be important, but if you gonna use them as surface functional agents on another carrier, determination of pore diameter might not be so important.
Hope these to be useful.
Pore size depend upon mesoporous and microporous.
There are many instrument around for porous measurement...to refine your search , go for surface area measuring instruments(BET, SEM,etc)...from my point would recommend for STM (scanning tunnling microscope) which have a piezoelectric material probe which will measure conductive/Non conductive materials .....
It depends on the type of nanoparticles you deals with. if it is reported to be microporous, mesoporous or macroporus, then you need to use BET analysis. It depends on methodology also, if you have used any templating agent during preparation then the material may be porous in nature. If TEM doesnt shows presence of pores it clearly indicates that your material is not mesoporous or macroporus. If size of your particle is 40 nm, I think there isnt any need to perform BET, your material my be microporous but its use is limited in pharma field as most of the guest molecules lies in the range of more than 4 nm in range.
In my opinion, your nanoparticles are nanogel because of nature of chitosan, then you can assess the adsorption capacity of your carriers by simple swelling test.
Small angle scattering techniques are a good choice to characterize materials in the scale length you mentioned in your topic (l
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