Biomedical Engineering Reference
In-Depth Information
order to be able to generate materials with adequate mechanical stabil-
ity. h e self-assembly method has advantages in the fact that it forms
a more natural binding site, and also of ers additional l exibility in the
types of monomers that can be polymerized. h e covalent method has
its advantages in generally of ering a high yield of homogeneous bind-
ing sites, but i rst requires the synthesis of a derivative imprint molecule
and may not imitate the “natural” conditions that could be present else-
where [5]. Over the recent years, interest in the technique of molecu-
lar imprinting has increased rapidly, both in the academic community
and in the industry. Consequently, signii cant progress has been made in
developing polymerization methods that produce adequate MIP formats
with rather good binding properties expecting an enhancement in the
performance or in order to suit the desirable i nal application, such as
beads, i lms or nanoparticles. One of the key issues that have limited the
performance of MIPs in practical applications so far is the lack of simple
and robust methods to synthesize MIPs in the optimum formats required
by the application. Chronologically, the i rst polymerization method
encountered for MIP was based on “bulk” or solution polymerization.
h is method is the most common technique used by groups working
on imprinting especially due to its simplicity and versatility. It is used
exclusively with organic solvents mainly with low dielectric constant and
consists basically of mixing all the components (template, monomer, sol-
vent and initiator) and subsequently polymerizing them. h e resultant
polymeric block is then pulverized, freed from the template, crushed and
sieved to obtain particles of irregular shape and size between 20 and 50
μm. Depending on the target (template) type and the i nal application
of the MIP, MIPs are appeared in dif erent formats such as nano/micro
spherical particles, nanowires and thin i lm or membranes. h ey are
produced with dif erent polymerization techniques like bulk, precipita-
tion, emulsion, suspension, dispersion, gelation, and multi-step swelling
polymerization. Most of investigators in the i eld of MIP are making MIP
with heuristic techniques such as hierarchical imprinting method. For
the i rst time the technique for MIP synthesis was done by Sellergren
et al.
[6] for imprinting small target molecules. With the same concept,
Nematollahzadeh
et al.
[7] developed a general technique, so-called
polymerization packed bed, to obtain a hierarchically structured high
capacity protein imprinted porous polymer beads by using silica porous
particles for protein recognition and capture. Recently, some rules were
very popularized for the MIP synthesis and that are collectively called as
“h
e MIP: Rule of six”
[8].
