Poly polymersomes

Upadhyay KK, Bhatt AN, Mishra AK, Dwarakanath BS, Jain S, Schatz C, Le Meins JE, Earooque A, Chandraiah G, Jain AK, Misra A, Lecommandoux S (2010) The intracellular drug delivery and anti tumor activity of doxorubicin loaded poly(y-benzyl L-glutamate)-b-hyaluronan polymersomes. Biomaterials 31(10) 2882... 

Encapsulated CPO in block copolymer polymersomes assembled from polystyrene-b-poly(L-isocyanoalanine-(2-thiophene-3-yl-ethyl)amide) The oxidation of two substrates by the encapsulated CPO was studied while the oxidation of pyrogallol was limited by diffusion into the polymersome, the rate-limiting step for the oxidation of thioansiole was the turnover by the enzyme [46]... 

Block copolymer vesicles, or polymersomes, are of continued interest for their ability to encapsulate aqueous compartments within relatively robust polymer bilayer shells (Fig. 7) [66, 67]. Eisenberg and coworkers were the first to report the formation of block copolymer vesicles from the self-assembly of polystyrene-h-poly(acrylic acid) (PS-h-PAA) block copolymers. They also have described the formation of a wide range of vesicle architectures in solution from the self-assembly of five different block copolymers PS-h-PAA. PS-h-PMMA, PB-h-PAA, polystyrene-h-poly(4-vinyIpyridinium methyl iodide), and polystyrene-h-(4-vinylpyridinium decyl iodide) [68]. Small uniform vesicles, large polydisperse vesicles, entrapped vesicles, hollow concentric vesicles, onions, and vesicles with hollow tubes in the walls have been observed and the formation mechanism discussed. Since vesicles could be prepared with low glass transition polymers such as PB [69, 70] and PPO [71], it has been established than these structures are thermodynamically stable and not trapped by the glassy nature of the hydrophobic part. 

Bates and coworkers have shown the enhanced mechanical properties of polymersomes compared to liposomes evaluated from different BC systems including poly(ethylene oxide)-b-poly(ethylene) (PEO-b-PE) and poly(ethylene oxide)-h-polybutadiene (PEO-h-PB) BCs with various block compositions [72]. Moreover, the... 

Fig. 21 Assembly of polymers via triple-hydrogen bonds, a Formula of the flavine/2,6-diamino-triazine and thymine/2,6-diaminotriazine interactions, b Formation of nanopar-ticles/polymer aggregates, c Polymersome formation by aggregation of poly(norbornenes) and poly(styrenes) bearing N-bisacyl-2,6-diamino-pyridine and thymine side-chains, respectively. Reprinted with permission from [104,105]...

Du and coworkers [122] prepared vesicles from poly(2-(methacryloyloxy)ethyl phosphorylcholine-fe-2-(diisopropylamino)ethyl methacrylate (PMPC-fe-PDPA) directly in water without any cosolvents. These vesicles are stable at physiological pH and completely dissociate below pH 6. Moreover, they are very close analogues of conventional liposomes due to the biomimetic phosphorylcholine motif. Further research demonstrated that these polymersomes are efficient systems for pH-controlled encapsulation and delivery of DNA [218],... 

Recently, the group of Battaglia used poly(2-(methacryloyloxy)ethyl-phosphorylcholine)-copoly(2-(diisopropylamino)ethyl methacrylate) (PMPC-PDPA) diblock copolymers to prepare biomimetic and pH-sensitive polymersomes for gene delivery [218]. These formulations encapsulated and released DNA in a pH-controlled manner. Notably, the pH drop was sufficient to trigger the transition from DNA-loaded vesicles to DNA-copolymer complexes. 

Hydrophobic blocks that are used for polymersome fabrication are inert polyethylethylene, polybutadiene, polystyrene, polydimethylsiloxane, degradable poly(lactic acid) (PLA), and poly(e-caprolactone) (PCL). Hydrophilic blocks include negatively charged poly(acrylic acid) and cross-linkable poly-methyloxazoline. Neutral PEG is more common for bioapplications. Among block copolymers, PEO-PLA and PEO-PCL are becoming widely adopted [26]. 

Finally similar transition can be induced by using UV-sensitive groups such as poly(ethylene oxide)-poly(methylphenylsilane) (PEO-PMPS) and azobenzene-containing poly(methacrylate)-poly(acrylic acid) (PAA-PAzoMA) [59]. More recently Mabrouk et al. [60] have shown an asymmetric polymersomes whose membrane has only one leaflet composed of UV-sensitive liquid-crystalline copolymer Poly(ethylene glycol)-poly(4-butyloxy-2-(4-(methacryloyloxy)butyloxy)-4-(4-butyloxybenzoyloxy)azobenzene) (PEG-fe-PMAazo444). Once exposed to UV light these polymersome burst due to changes in the spontaneous curvature of the membrane. 

Najafi E, Sarbolouki MN (2003) Biodegradable micelles/polymersomes from fumaric/sebacic acids and poly (ethylene glycol). Biomaterials 24 1175-1182... 

Upadhyay KK, Meins J-FL, Misra A, Voisin P, Bouchaud V, Ibaiboure E, Schatz C, Lecommandoux S (2009) Biomimetic doxorabicin loaded polymersomes from hyaluronan-block-poly(benzyl glutamate) copolymers. Biomacromolecules 10(10) 2802—2808... 

Flexible polymersomes Poly(caprolactone)-poly(ethylene glycol)-poly(caprolactone) copolymer Anticancer Targeting melanomas and basal cell carcinomas [111]... 

Caon, T, Porto, L. C., Granada, A., Tagliari, M. R, Silva, M. A. S., Simoes C. M. 0., Borsali, R., Soldi, V. (2014). Chitosan-decorated polystyrene-b-poly (acrylic acid) polymersomes as novel carriers for topical delivery of finasteride, 52,165-172. 

FIGURE 4.13 TEM of polymersomes at pH 3 (a) and 10 (b). Membrane consists of protonable poly(diethylaminoethyl methacrylate) (PDEAEM), which is responsible for the swelling/deswelling properties of pol3mersome. Source Gaitzsch et al. [32]. Reproduced with permission of John Wiley Sons. 

The potential of self-assembly of functional block copolymers with the aim to confine functionality in a specific compartment is well demonstrated by the formation of functional polymersomes (Section 6.1.1.2). As an example, Meier et al. [20] prepared polymersomes composed of poly(dimethylsiloxane)- /oc -poly(2-methyloxazoline) diblock copolymers that had been modified... 

Due to its high stability, the membrane of polymersomes has low fluidity, which leads to a very limited ttansport through the membrane. Thus, in order to allow for transmembrane transport, specific efforts are necessary. One option is the use of responsive polymer blocks, which allow a switching of the block from hydrophilic to hydrophobic, or vice versa. This can be achieved with thermo-responsive poly(Af-isopropylacrylamide) (PNIPAM), pH-sensitive amino-functionalized methacryl derivatives (e.g., poly(diethylaminoethyl methacrylate) (PDEAEM)), or the redox-sensitive poly(propylene sulfide) (PPS). 

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