Photo-sensitive Polymer Nanoparticles

Abstract:   

Functional and stimuli-responsive polymers and colloids have attracted great scientific and technological interest and have been proposed for a wide range of applications in nano- and bio-technology.1 Among them, the use of photons to alter or control the materials properties has attracted particular attention, because light is a remote stimulus, it allows spatiotemporal control and is often inexpensive and readily available. Light-responsive and light-sensitive polymers have been extensively investigated.2 Herein our latest developments in this field will be discussed.

Multi-responsive, amphiphilic diblock copolymers, that exhibit a cooperative response to three different external stimuli, are dicussed.3 The copolymers comprise a hydrophobic spiropyran-based block and a hydrophilic poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) block and self-assemble into spherical structures in water, with the pH-, temperature- and light-responsive spiropyran block in the core of the structures and the pH- and temperature-responsive PDMAEMA chains extending in water to stabilized the colloidal structures. The effect of the three stimuli on the characteristics of the self-assembled structures, and the cooperative response and structural reorganization of the latter, when applying the external triggers, are investigated.

Next, a novel NIR-photoactivated chemically amplified drug release system, which combines acid-degradable nanocarriers, based on PEG-b-polyacetal block copolymer assemblies, with a photosensitization system comprising a photo-acid generator (PAG), that absorbs in the UV region, and photosensitizing molecules, that absorb in the NIR, is presented.4 The degradation of the nanocarriers, based on the acid-catalyzed cleavage of the acetal bonds along the main chain of the polyacetal block, by the generation of acid molecules via an electron transfer process from the excited photosensitizer molecules to the PAG, both loaded within the cores of the block copolymer structures, is shown, opening new pathways in photo-activated drug delivery.

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References

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2.  G. Pasparakis T. Manouras, P. Argitis and M. Vamvakaki Macromol. Rapid Commun. 2012, 33, 183-198; Th. Manouras and M. Vamvakaki Polym. Chem. 2017, 8, 74.

3.  P. G. Falireas and M. Vamvakaki Macromolecules 2018, 51, 6848; P. G. Falireas and M. Vamvakaki 2021, submitted.

4.  G. Pasparakis T. Manouras, M. Vamvakaki and P. Argitis Nature Commun. 2014, 5, 3623; M. Psarrou, Th. Manouras, I. Peraki and M. Vamvakaki, 2021, submitted.