Fabrication and Decryption of a Microarray of Digital Dithiosuccinimide Oligomers.

Digital polymers with precisely arranged binary units provide an important option for information storage. This is especially true if the digital polymers are assembled in a device, as it would be of great benefit for data writing and reading in practice. Herein, inspired by the DNA microarray technique, the programmable information storing and reading on a mass spectrometry target plate is proposed. First, an array of 4-bit sequence-coded dithiosuccinimide oligomers is efficiently built through sequential thiol-maleimide Michael couplings with good sequence readability by tandem mass spectrometry (MS/MS). Then, toward engineering microarrays for information storage, a programmed robotic arm is specifically designed for precisely loading sequence-coded oligomers onto the target plate, and a decoding software is developed for efficient readout of the data from MS/MS sequencing. Notably, short sequence-coded oligomer chains can be used to write long strings of information, and extra error-correction codes are not required as usual due to the inherent concomitant fragmentation signals. Not only text but also bitimages can be automatically stored and decoded with excellent accuracy. This work provides a promising platform of digital polymers for programmable information storing and reading.

Polymerization-Induced Helicity Inversion Driven by Stacking Modes and Self-Assembly Pathway Differentiation.

Regulating the mutual stacking arrangements is of great interest for understanding the origin of chirality at different hierarchical levels in nature. Different from molecular level chirality, the control and manipulation of hierarchical chirality in polymer systems is limited to the use of external factors as the energetically demanding switching stimulus. Herein, the first self-assembly strategy of polymerization-induced helicity inversion (PIHI), in which the controlled packing and dynamic stereomutation of azobenzene (Azo) building blocks are realized by in situ polymerization without any external stimulus, is reported. A multiple helicity inversion and intriguing helix-helix transition of polymeric supramolecular nanofibers occurs during polymerization, which is collectively confirmed to be mediated by the transition between functionality-oriented π-π stacking, H-, and J-aggregation. The studies further reveal that helicity inversion proceeds through a delicate interplay of the thermodynamically and kinetically controlled, pathway-dependent interconversion process, which should provide new insight into the origin and handedness control of helical nanostructures with desired chirality.

Engineering Achiral Liquid Crystalline Polymers for Chiral Self-Recovery.

Flexible construction of permanently stored supramolecular chirality with stimulus-responsiveness remains a big challenge. Herein, we describe an efficient method to realize the transfer and storage of chirality in intrinsically achiral films of a side-chain polymeric liquid crystal system by combining chiral doping and cross-linking strategy. Even the helical structure was destroyed by UV light irradiation, the memorized chiral information in the covalent network enabled complete self-recovery of the original chiral superstructure. These results allowed the building of a novel chiroptical switch without any additional chiral source in multiple types of liquid crystal polymers, which may be one of the competitive candidates for use in stimulus-responsive chiro-optical devices.

A natural polyphenol-functionalized chitosan/gelatin sponge for accelerating hemostasis and infected wound healing.

Natural polymers have been particularly appealing for constructing hemostatic materials/devices, but it is still desirable to develop new natural polymer-based biomaterials with balanced hemostatic and wound-healing performance. In this work, a natural polyphenol-functionalized chitosan/gelatin sponge (PCGS) was prepared by the lyophilization of a chitosan/gelatin mixture solution (under a self-foaming condition to prepare the CGS) and subsequent chemical cross-linking with procyanidin (PC). Compared with the original CGS, PCGS exhibited an enhanced liquid-absorption ability, reduced surface charges, and similar/low hemolysis rate. Benefiting from such a liquid-absorption ability (∼4000% for whole blood and normal saline) and moderate surface charges, PCGS exhibited high in vitro hemostatic property and promising hemostatic performance in an in vivo femoral-artery-injury model. In addition, PCGS possessed higher antioxidant property and slightly decreased antibacterial ability than CGS, owing to the incorporation of PC. The feasibility of PCGS for treating infected wounds was further confirmed in an in vivo infected-tooth-extraction model, as the typical complication of intractable tooth-extraction bleeding. The present work demonstrated a facile approach for developing multifunctional hemostatic materials through the flexible management of natural polymers and polyphenols.

Chiral Expression and Morphology Control in Polymer Dispersion Systems.

The chiral self-assembly of polymers in dispersions plays an important role in chiral chemistry and self-assembly. In general, both polymerization-induced self-assembly (PISA) and post-polymerization self-assembly can be used to prepare polymer nanoassemblies. In chirality induction or transfer processes, the self-assembly manner of the polymers greatly affects the chiral expression of the nanostructure and cannot be ignored in the chiral fields. Moreover, unique chiral expression and morphological transition of polymer assemblies in dispersions enable the preparation of advanced functional chiroptical materials. Herein, this Review discusses recent advances in chiral expression and morphology control in polymer dispersion systems, particularly the comparison between traditional post-polymerization self-assembly and in situ PISA strategies, to predict and advance chirality control in polymers.