Fabrication and Characterization of Hollow Microcapsules from Polyelectrolytes Bearing Thymine Pendant Groups for Ultraviolet‐B (UVB)‐Induced Crosslinking

Abstract

DNA – bioinspired polyelectrolytes poly[vinylbenzylthymine (VBT)‐4‐vinylbenzyltriethylammonium chloride (VBA)] and poly[vinylbenzylthymine (VBT)‐4‐vinylphenylsufonate (VPS)] were used for the preparation of hollow microcapsules (HMC) using the layer‐by‐layer method and CaCO3 microspheres as removable molds. Stable aqueous suspensions of spherical‐shaped HMCs with a shell composed of six layers of VBA‐based polyelectrolytes were obtained, of approximately (7.0±1.5) μm diameter and a shell thickness of 1 μm. Ultraviolet‐B irradiation of the HMC suspensions induces an efficient crosslinking between adjacent polyelectrolyte chains through the formation of thymine photodimers, such as the cyclobutane pyrimidine dimer (CPD) and the (6–4) pyrimidine–pyrimidone photoproduct (6–4PP). This process resulted in a reduction of the average interstitial mesh size of the HMC shells, modulating their permeability properties and increasing the mechanical stability of the HMC without a noticeable modification of size and shape. Thus, the DNA‐bioinspired polyelectrolytes are promising materials for the preparation of UVB‐responsive HMCs.

Nanoparticles in Polyelectrolyte Multilayer Layer-by-Layer (LbL) Films and Capsules—Key Enabling Components of Hybrid Coatings

“…Crosslinking affects the mechanical properties of a capsule. For example, it was shown recently that synthesis of hollow polyelectrolyte capsules with ultraviolet-B-induced crosslinking was achieved by inclusion of thymine pendant groups in polyelectrolyte molecule [228]. One more recent example includes investigation of capsules crosslinked via amino/betaine dual-functional copolymers, also used for cell encapsulation [229].…”

“On-Demand” Antimicrobial Photodynamic Activity through Supramolecular Photosensitizers Built with Rose Bengal and (p-Vinylbenzyl)triethylammomium Polycation Derivatives

“…The selection of these aromatic polycations is based on their ability to interact with dye molecules through various types of intermolecular interactions, for example, from π-stacking to electrostatic attractive forces . Furthermore, in the case of the copolymer obtained by combining vinylbenzylthymine (VBT) and vinyltriethylammonium chloride (VBA) monomers, the VBT moiety can also produce multiple hydrogen-bonding interactions and photo-cross-linking through the formation of thymine dimers to obtain polymer films, , core-cross-linked micelles, and shell-cross-linked hollow microcapsules, with different capabilities such as bacteriostatic, drug delivery, and selective molecular permeation.…”

Anti Regiospecificity in the Photosensitized Cycloaddition of 4‐Tetrazolouracil Nucleoside†

“…The UV-light induced [2 + 2] cycloaddition reaction of DNA pyrimidines has numerous deleterious impacts on living organisms (1,2) with repercussion on ecosystems (3). Nonetheless, molecular biology (4,5), polymer/material science (6)(7)(8) and nanosciences (9,10) have been able to drive important benefits from this natural light-driven reaction. In B DNA, the [2 + 2] cycloaddition reaction is regiospecific by affording only "headto-head" (syn) adducts, and also highly stereoselective, with a predominant cis adduct formation, due to the sugar phosphate backbone conformation and base pairing constraints (11).…”