The use of aliphatic polyesters in drug delivery applications has been a field of significant interest spanning decades. Drug delivery strategies have made abundant use of polyesters in their structures owing to their biocompatibility and biodegradability. The properties afforded from these materials provide many avenues for the tunability of drug delivery systems to suit individual needs of diverse applications. Polyesters can be formed in several different ways, but the most prevalent is the ring-opening polymerization of cyclic esters. When used to form amphiphilic block copolymers, these materials can be utilized to form various drug carriers such as nanoparticles, micelles, and polymersomes. These drug delivery systems can be tailored through the addition of targeting moieties and the addition of stimuli-responsive groups into the polymer chains. There are also different types of polyesters that can be used to modify the degradation rates or mechanical properties. Here, we discuss the reasons that polyesters have become so popular, the current research focuses, and what the future holds for these materials in drug delivery applications. WIREs Nanomed Nanobiotechnol 2017, 9:e1446. doi: 10.1002/wnan.1446 For further resources related to this article, please visit the WIREs website.

Organic semiconducting materials derived from πelectron-rich pyrroles have garnered attention in recent years for the development of organic semiconductors. Although pyrrole is the most electron-rich five-membered heteroaromatic ring, it has found few applications in organic photovoltaics and organic field-effect transistors due to synthetic challenges and instability. However, computational modeling assisted screening processes have indicated that relatively stable materials containing pyrrolic units can be synthesized without compromising their inherent electron-donating properties. In this work, we provide a complete, up-to-date review of pyrrole-containing semiconducting materials used for organic photovoltaics and organic field-effect transistors and highlight recent advances in the synthesis of these materials.

Combined loading of doxorubicin (DOX) and resveratrol (RSV) in polymeric micelles enabled an increased loading of DOX into a micellar drug delivery system. Herein, we report the coloading of DOX and RSV in amphiphilic diblock copolymer micelles of poly­(ethylene glycol)-b-poly­(ε-caprolactone) (PEG-b-PCL) and poly­(ethylene glycol)-b-poly­(γ-benzyl-ε-caprolactone) (PEG-b-PBCL) for which an increase in the loading efficiency and increased in vitro cytotoxicity was observed. The increased loading was attributed to the favorable interactions of DOX and RSV as well as to the interaction with benzyl substituents of PEG-b-PBCL diblock copolymer micelles. Combination loaded micelles made of PEG-b-PBCL diblock copolymer showed a dramatic improvement in DOX loading in comparison to DOX-only loaded PEG-b-PBCL with an increase in encapsulation efficiency of DOX from 31.0 to 87.7%. Combination loaded micelles also showed increased cytotoxicity to HeLa cells as compared to that of DOX-only loaded micelles. Optimization of the combination loading, size and morphology, drug release, and cellular studies is also reported here. Combination loading was shown to improve the loading capacity and efficiency of both systems and shows promise to improve loading of DOX in polymer micelle systems regardless of the polymer used.

We report two banana-shaped organic semiconducting small molecules containing the relatively unexplored thieno[3,2- b]pyrrole with thiophene and furan flanked benzothiadiazole. Theoretical insights gained by DFT calculations, supported by single crystal structures show that furan flanked benzothiadiazole-thieno[3,2- b]pyrrole small molecule has a higher curvature compared to the thiophene flanked small molecule due to the shorter carbon-oxygen bond in furan. Despite similar optical and electrochemical properties, thiophene flanked small molecule shows average hole mobility up to 8 × 10 cm V s, however furan flanked small molecule performs poorly in thin film transistor devices (μ ≈ 5 × 10 cm V s). The drastic difference in hole mobilities was due to the annealing-induced crystallinity which was demonstrated by the out-of-plane grazing incidence X-ray diffraction and surface morphology studies by tapping mode atomic force microscopy analysis.

The smallest entries of S,N- and O,N-heteroacenes are systematically investigated in donor–acceptor–donor type small molecules toward OFETs.