1 research outputs found
Immobilized Multifunctional Polymersomes on Solid Surfaces: Infrared Light-Induced Selective Photochemical Reactions, pH Responsive Behavior, and Probing Mechanical Properties under Liquid Phase
Fixing polymersomes onto surfaces
is in high demand not only for the characterization with advanced
microscopy techniques but also for designing specific compartments
in microsystem devices in the scope of nanobiotechnology. For this
purpose, this study reports the immobilization of multifunctional,
responsive, and photo-cross-linked polymersomes on solid substrates
by utilizing strong adamantane−β-cyclodextrin host–guest
interactions. To reduce nonspecific binding and retain better spherical
shape, the level of attractive forces acting on the immobilized polymersomes
was tuned through polyÂ(ethylene glycol) passivation as well as decreased β-cyclodextrin
content on the corresponding substrates. One significant feature of
this system is the pH responsivity of the polymersomes which has been
demonstrated by swelling of the immobilized vesicles at acidic condition
through in situ AFM measurements. Also, light responsivity has been
provided by introducing nitroveratryloxycarbonyl (NVOC) protected
amine molecules as photocleavable groups to the polymersome surface
before immobilization. The subsequent low-energy femtosecond pulsed
laser irradiation resulted in the cleavage of NVOC groups on immobilized
polymersomes which in turn led to free amino groups as an additional
functionality. The freed amines were further conjugated with a fluorescent
dye having an activated ester that illustrates the concept of bio/chemo
recognition for a potential binding of biological compounds. In addition
to the responsive nature, the mechanical stability of the analyzed
polymersomes was supported by computing Young’s modulus and
bending modulus of the membrane through force curves obtained by atomic
force microscopy measurements. Overall, polymersomes with a robust
and pH-swellable membrane combined with effective light responsive
behavior are promising tools to design smart and stable compartments
on surfaces for the development of microsystem devices such as chemo/biosensors