Supramolecular systems for bioapplications:recent research progress in China

Supramolecular systems feature dynamic,reversible and stimuli-responsive characteristics,which are not easily achieved by molecular entities.The last decade has witnessed tremendous advances in the investigations of supramolecular systems for various bioapplications,which include drug delivery,anticancer therapy,antibacterial therapy,photodynamic therapy,photothermal therapy,combination therapy,antidotes for residual drugs or toxins,and bioimaging and biosensing.Host-guest chemistry has played a key role in the development of such bioactive supramolecular systems,and natural macrocycles(such as cyclodextrins),synthetic macrocycles(such as calixarenes,cucurbit[n]urils,and pillararenes),and porous framework polymers(such as supramolecular organic frameworks and flexible organic frameworks)have been most successfully used as hosts to build different kinds of host-guest systems for attaining designed biofunctions.The self-assembly of rationally designed amphiphilic molecules,macromolecules and polymers represent another important approach for the construction of supramolecular architectures with advanced biofunctions.In this review,we summarize the important contributions made by Chinese researchers in this field,with emphasis on those reported in the past five years.

Pillar[5]arene-modified peptide-guanidiniocarbonylpyrrol amphiphiles with gene transfection properties

Pillar[5]arene-modified amphiphilic peptides with varying numbers of guanidiniocarbonylpyrrol(GCP)moieties have been successfully synthesized,which can self-assemble to multivalent cationic superstructures in aqueous solutions.These assembled peptides can condense DNA into various compact multimolecular aggregates to achieve successful intracellular DNA delivery and demonstrate great potential for gene transfection.Transfection efficiencies of the self-assembled superstructures have been evaluated in vitro with He La and HEK 293T cells.We demonstrate that GCP moiety could enhance the cell transfection ability,owing to its excellent binding towards cytomembrane.It was also found that subtle structure difference in peptides 2 and 3 could result in distinct transfection efficacy,which makes it possible to gain an in-depth understanding of their structure-activity relationship.This work presents a good example of rational structural design in achieving effective gene transfection vectors.

杯芳烃和柱芳烃桥梁部位的衍生及其功能化

随着大环化学的快速发展,对杯芳烃、柱芳烃及其他类似化合物的桥梁亚甲基部位进行高效修饰的方法日益引起人们的关注.桥梁部位修饰后的大环衍生物,在不改变其原有属性的基础上增加了新的功能,不仅可以引入更多的功能基团,而且可以通过主客体的自组装行为,进一步拓展杯芳烃和柱芳烃等超分子大环在药物递送、化学传感、荧光体系构建等诸多领域的应用.本文对杯芳烃和柱芳烃桥梁部位修饰的研究进展进行了综述.按照修饰方法的不同进行分类,系统阐述了杯芳烃和柱芳烃桥梁部位修饰的方法、修饰后结构的变化,以及相应的应用拓展,并进一步讨论了其未来发展所面临的机遇与挑战.

Supramolecular Nanohelix Fabricated by Pillararene-Based Host–Guest System for Chirality Amplification, Transfer, and Circularly Polarized Luminescence in Water

Amplified chirality and Förster resonance energy transfer(FRET)-assisted chirality transfer frommolecular to nanoscale level have been shown to play a vital role in co-assembled nanohelix for potential energy transfer in biological systems.Herein,we have constructed a chiral host–guest complex donor system for chiral amplification via induced chirality of pillar[5]arene host and loaded it with an achiral dye acceptor to demonstrate how chirality-assisted excitation energy transfer occurred in the supramolecular nanohelix system in an aqueous medium.

An AIE singlet oxygen generation system based on supramolecular strategy

The design of supramolecular system s with efficient singlet oxygen generation has attracted considerable interests.Herein,an AIE-based singlet oxygen generation system with chemiluminescence properties is reported in aqueous media based on supramolecular host-guest assembly between a water-soluble pillar[5]arene(WP5)and an AIE photosensitizer(TPEDM).The formed supramolecular nanoparticles exhibit significant singlet oxygen generation ability as well as enhanced fluorescence.In addition,by introducing catalase,this H_(2) O_(2)-responsive supramolecular system shows increased~1 O_(2) generation efficiency compared with the blank nanoparticles.An efficient chemiluminescence system can also be achieved by entrapping an energy donor adamantane derivative(AMPPD).Moreover,the present system can function as nanoreactors to perform the photooxidation of dopamine to form polydopamine with visible light irradiation.This wo rk provides a new strategy for the construction of~1 O_(2) generation system based on supramolecular nanomaterials,which has potential applications in the fields such as chemiluminescence imaging and controlled photocatalysis.

The construction of aggregation-induced charge transfer emission systems in aqueous solution directed by supramolecular strategy

Novel aggregation-induced charge transfer(CT) emission systems with long luminescence lifetime directed by supramolecular strategy have been successfully developed in water. The dimethylacridine-based electron donor(Br Ac) with excellent aggregation ability can co-aggregate with a triazine-based electron acceptor(TRZ) to form nanorods in water, which exhibit CT emission with long lifetime(τ = 0.92 μs).As for a similar electron donor(Qa Ac) with poor aggregation ability, water-soluble pillar[5]arene(WP5)can be introduced to promote the aggregation process, leading to the obvious CT emission with long lifetime(τ = 0.61 μs). In addition, structural modification of the acceptor with substituent groups possessing stronger electron-accepting capabilities will cause red-shift(about 50 nm) of the emission, which allows conveniently constructing long lifetime organic luminescent materials with different emission colors.