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Covalent organic frameworks (COFs) are an emerging kind of crystalline porous polymers which present the precise integration of organic building blocks into extensible structures with regular pores and periodic skeletons. The diversity of organic units and covalent linkages makes COFs a rising materials platform for the design of structure and functionality. In this review, we summarize the recent research progress in developing COFs for photoluminescent materials. We highlight structural and functional design strategies, and identify fundamental problems that need to be solved in conjunction with potential applications from perspectives of photoluminescent materials.

Crystalline porous materials (CPMs) not only present the precise integration of molecular building blocks into extensible structures with periodic frameworks and regular pores, but also provide limited molecular spaces for the interactions of guest molecules, electrons and photons. Incorporating aggregation-induced emission (AIE)-based units into crystalline porous frameworks can result in unique luminescent properties. AIE-based CPMs have widely tunable composition, high luminescent efficiency and good photo-stability, which make them useful for biomedical applications involving bio-sensing, bio-imaging and imaging-guided therapies. This review focused on structure design and luminescent property modulation of AIE-based CPMs with highlights on their applications in biomedical fields. The prospect and challenges in the development of AIE-based CPMs from chemistry, materials to biomedical applications were also discussed.

Fluorescent materials exhibiting two-photon induction (TPI) are used for nonlinear optics, bioimaging, and phototherapy. Polymerizations of molecular chromophores to form π-conjugated structures were hindered by the lack of long-range ordering in the structure and strong π-π stacking between the chromophores. Reported here is the rational design of a benzothiadiazole-based covalent organic framework (COF) for promoting TPI and obtaining efficient two-photon induced fluorescence emissions. Characterization and spectroscopic data revealed that the enhancement in TPI performance is attributed to the donor-π-acceptor-π-donor configuration and regular intervals of the chromophores, the large π-conjugation domain, and the long-range order of COF crystals. The crystalline structure of TPI-COF attenuates the π-π stacking interactions between the layers, and overcomes aggregation-caused emission quenching of the chromophores for improving near-infrared two-photon induced fluorescence imaging.

Polycyclic aromatic derivatives can trap 1 O2 to form endoperoxides (EPOs) for O2 storage and as sources of reactive oxygen species. However, these materials suffer from structural amorphism, which limit both practical applications and fundamental studies on their structural optimization for O2 capture and release. Metal-organic frameworks (MOFs) offer advantages in O2 binding, such as clear structure-performance relationships and precise controllability. Herein, we report the reversible binding of O2 is realized via the chemical transformation between anthracene-based and the corresponding EPO-based MOF. It is shown that anthracene-based MOF, the framework featuring linkers with polycyclic aromatic structure, can rapidly trap 1 O2 to form EPOs and can be restored upon UV irradiation or heating to release O2 . Furthermore, we confirm that photosensitizer-incorporated anthracene-based MOF are promising candidates for reversible O2 carriers controlled by switching Vis/UV irradiation.

Photodynamic therapy (PDT) is widely researched in tumor treatment, but its therapeutic effect is affected by oxygen (O

Using the cytomembranes (FMs) of hybrid cells acquired from the fusion of cancer and dendritic cells (DCs), this study offers a biologically derived platform for the combination of immunotherapy and traditional oncotherapy approaches. Due to the immunoactivation implicated in the cellular fusion, FMs can effectively express whole cancer antigens and immunological co-stimulatory molecules for robust immunotherapy. FMs share the tumor's self-targeting character with the parent cancer cells. In bilateral tumor-bearing mouse models, the FM-coated nanophotosensitizer causes durable immunoresponse to inhibit the rebound of primary tumors post-nanophotosensitizer-induced photodynamic therapy (PDT). The FM-induced immunotherapy displays ultrahigh antitumor effects even comparable to that of PDT. On the other hand, PDT toward primary tumors enhances the immunotherapy-caused regression of the irradiation-free distant tumors. Consequently, both the primary and the distant tumors are almost completely eliminated. This tumor-specific immunotherapy-based nanoplatform is potentially expandable to multiple tumor types and readily equipped with diverse functions owing to the flexible nanoparticle options.