Poly(Alkyl Cyanoacrylate) Nanosystems - Intracellular Delivery: Fundamentals and Applications - page 231

Kamachi et al. 1981 ; Yamada et al. 1983 ). This was successfully applied to bulk
or solution homopolymerization and copolymerization of methyl cyanoacrylate
(MCA) and ECA in the 30-60°C temperature range (Canale et al. 1960 ; Bevington
et al. 1976 ; Yamada et al. 1983 ).
Alkyl cyanoacrylates were also copolymerized with methyl methacrylate
(MMA) or styrene via a free-radical process in bulk or solution to yield random or
alternating copolymers, respectively (Kinsinger et al. 1965 ). MCA or isobutyl
cyanoacrylate (IBCA) were also copolymerized with difunctional alkyl cyanoacry-
lates and yielded crosslinked macromolecular adhesive compositions with superior
mechanical properties than the noncrosslinked counterparts (Buck 1978 ). Free-
radical bulk copolymerization of ECA and MMA was also undertaken to yield
poly(ECA- co -MMA) (P(ECA- co -MMA)) random copolymers with various monomer
compositions (Han and Kim 2009 ). Incorporation of MMA monomer units within
the polymer structure conducted to both a better stability upon degradation and a
lower glass transition temperature than PECA homopolymer. This can be seen as
an easy method to tune the properties of the polymer depending on the application
envisioned.
Recently, honeycomb-patterned PACA films were prepared from the chloroform
solutions of ECA, n BCA or OCA by breath figures (BFs) method (Li et al. 2010 ).
Condensed water droplets on the solution surface acted not only as templates to
endow the ordered structure but also as initiators to trigger the polymerization of
the monomer. After the polymerization started, the in situ formed polymer chains
self-assembled around the water droplets, structuring PACA film with a hexagonal
arrangement of holes. The cell proliferation assay revealed that: (i) porous mor-
phology was more beneficial to Hela cell proliferation than the flat film and (ii) the
longer the side-chain of the monomer, the better the biocompatibility.

3.2 Macromolecular Architectures

The high reactivity of alkyl cyanoacrylates tends to make the synthesis complex
macromolecular architectures extremely difficult. However, several attempts
succeeded in the preparation of sophisticated copolymers. For instance, diblock and
triblock copolymers involving alkyl cyanoacrylates were prepared from triphe-
nylphosphine end-capped monohydroxyl and dihydroxyl poly(ethylene glycol)
(PEG) acting here as mono- or difunctional macroinitiators for the zwitterionic
polymerization of IBCA. PIBCA- b -PEG diblock and PIBCA- b -PEG- b -PIBCA
triblock copolymers were then prepared with variable compositions and different
molar masses by simply playing with the initial stoichiometry (Choi et al. 1995 ).
Similarly, a PECA- b -PEG- b -PECA triblock copolymer was synthesized by oxyanion-
initiated polymerization from sodium difunctional alcoholate-terminated PEG
macroinitiator (Lin et al. 2008 ).
Another approach consisted in the synthesis of amphiphilic comblike
poly[(hexadecyl cyanoacrylate)- co -methoxypoly(ethylene glycol) cyanoacrylate]