Nano Level Characterisation of DMAEMA – Based cationic polymer for transfer DNA


1: Department of Industrial Pharmacy, Faculty of Pharmacy, Alfateh University,&  Biotechnology Research Centre- Nanotechnology research gp., Libya
2: Laboratory of Biophysics and Surface Analysis, the School of Pharmaceutical Sciences, the University of Nottingham NG7 2RD UK.
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Nano Level Characterisation of DMAEMA – Based cationic polymer for transfer DNA


7th INTRACOM – 2nd ICBWI 2009


24th July 2009

Place Held

PWTC, Kuala Lumpur


The ability of transfer the DNA to the cell by a synthetic vector is one of the fundamental goals in biotechnology. Towards this end, the polymeric vector is considered a promising delivery vector; therefore the past several years have seen a considerable growth in the use of cationic polymers for gene delivery. This results from the realization that their unique architecture can translate into unusual chemical and physical properties and lead to a success in use as vectors for gene delivery.

The physicochemical properties of many cationic polymers are often polar, highly functionalized, and soluble in water.  They are dependant on their shape, as well as the presence of high positive charge density of protonized primary amine groups on their surface.  Together with high solubility in water, these characteristics have led to the use of these polyamines to mediate efficient DNA transfer into numerous cell lines in vitro.

The combination of Atomic Force Microscope AFM and Transmission Electron Microscope TEM can provide a range of morphological data. The basic structural knowledge and information about the DMAEMA-based polymer systems individually at nano level, morphology, size, and width were analysed by both AFM and TEM. TEM image of DMAEMA homopolymer stained with a uranyl acetate stain.  A large number of apparent individual molecules are observed; also small islands of aggregated materials are seen.  The investigation of diameter of DMAEMA polymers show mean width ranging between 22.4 nm to 26.8 nm by AFM (figure 1) and 16.9 nm to 24.75 nm by TEM (figure 2). The diameter of the molecules imaged by TEM observed less, and many factors could affect such a dramatic decrease in the diameter, such as the dehydration during the sample preparation and staining process. AFM and TEM measurements show a globular morphology.

The AFM data shows the diameter always to be larger than the height, indicating that the cationic polymers molecules are no longer globular or spherical but instead it seems dome-shaped when deposited on a mica surface, it is believed the compression of the tip influenced significant role in its formation as presented and the tip convolution could has additional effects on the formed complexes.  The behaviour of the resulting polymer morphology was a compact globular structure.  It is believed the interaction between surface groups along with short range Van der Waals forces are considered to be responsible for formation of the observed compact globular structures. Lastly, the observation was made to individual nano-scale molecules and both techniques displayed a similar structural morphology for the polymer, which is a nano-globular structure.




Symposium 2C (ICBWI)


Biomolecule Discovery