Biomedical Engineering Reference
In-Depth Information
they deduce the possible morphology of a collapsed supramolecular
single molecule (Figure 2.2) [35]. Thermal characteristics also
change after the formation of the SCPN [35, 51], and in some cases
the solubility of the polymeric chain diff ers from the collapsed coil in
certain solvents [34, 54].
Figure 2.2
High-resolution AFM scan of individual SCNP: (A) Group of a
few particles. (B) Height, amplitude, and phase images clearly indicating
the complex geometry and raised core. (C) Three-dimensional height
image with phase retrace overlay of this particle. (D) Cartoon depicting the
possible particle morphology: 2-ureido-pyrimidinone (UPy)-urethane rich
core (blue) immersed in a network of PMMA. Reproduced from ref. [35]
with permission. See also Color Insert.
In relation to nanomedical applications, the feature that makes
this type of nanoparticle so attractive is their small size. Up to now,
the most successful nanocarriers, such as dendrimers, have had
dimensions between 1 and 10 nm. That is one of the reasons why it
would be desirable to obtain SCNPs with comparable proportions.
As has been mentioned before, the size varies in relation to the
molecular weight and chemical nature of the precursor polymer,
as well as the amount of cross-links that are formed during the
collapse. Depending on the major functional groups, the behaviour
of the final nanoparticle varies when changing molecular weight and
percentage of cross-linking units. The majority of SCNPs obtained
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