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Organic room‐temperature phosphorescence (RTP) materials are actively explored as attractive candidates for optoelectronic and bioelectronics applications given their unique long‐lived excited‐state features and inherent merits of low‐cost, appreciable functionality, and good biocompatibility. In recent years, many efforts in molecular design and aggregation modulation are devoted to achiev efficient RTP from organics, among which an emerging strategy focuses on confining chromophores within polymer matrices. Polymers possess intertwined chains making them a good platform to restrain the nonradiative decays and quenching, allowing the triplet excitons to survive a long time enough for emission at room temperature. Progress relating to polymer‐based organic RTP materials is highlighted as a new creative subject in the field. This review outlines recent advancements in polymer‐based organic RTP materials. The fundamental mechanism of organic RTP is first presented. Thereafter, design considerations and strategies to construct polymer‐based organic RTP materials are summarized in detail. Several promising progresses in the proposed use of these RTP materials, such as encryption and anti‐counterfeiting, sensors, and bioimaging are overviewed. Finally, the challenges and future perspectives are discussed to emphasize the directions that deserve focus attention in the field. [ABSTRACT FROM AUTHOR]

Double‐network (DN) hydrogels consisting of noncovalent interacting networks are highly desired due to their well‐controlled compositions and environmental friendliness, but the low water resistance always impairs their mechanical strength. Here, an anti‐swelling hydrogel possessing the core/shell architecture through rational regulation of multiple weak noncovalent interactions is prepared. A composite hydrogel consists of chitosan (CS) and poly(N‐acryloyl 2‐glycine) (PACG), readily forming the shell‐structured DN hydrogel after soaking in a FeCl3 solution because of in situ formation of chain entanglements, hydrogen bonds, and ionic coordination. The produced DN hydrogels exhibit excellent anti‐swelling behaviors and mechanical durability for over half a year, even in some strict situations. Taking the merits of noncovalent bonds in adjustability and reversibility, the swelling property of these hydrogels can be easily customized through control of the ion species and concentrations. A dynamically reversible transition from super‐swelling to anti‐swelling is realized by breaking up and rebuilding the metal‐coordination complexes. This facile but efficient strategy of turning the noncovalent interactions and consequently the mechanics and anti‐swelling properties is imperative to achieve the rational design of high‐performance hydrogels with specific usage requirements and expand their applicability to a higher stage. [ABSTRACT FROM AUTHOR]

Development of artificial biomaterials by mimicking extracellular matrix of bone tissue is a promising strategy for bone regeneration. Hydrogel has emerged as a type of viable substitute, but its inhomogeneous networks and weak mechanics greatly impede clinical applications. Here, a dual crosslinked gelling system is developed with tunable architectures and mechanics to promote osteogenic capacity. Polyhedral oligomeric silsesquioxane (POSS) is designated as a rigid core surrounded by six disulfide‐linked PEG shells and two 2‐ureido‐4[1H]‐pyrimidinone (UPy) groups. Thiol‐disulfide exchange is employed to fabricate chemical network because of the pH‐responsive "on/off" function. While self‐complementary UPy motif is capable of optimizing local microstructure to enhance mechanical properties. Taking the merits of biocompatibility and high‐mechanics in periodontal ligament stem cells (PDLSCs) proliferation, attachment, and osteogenesis, hybrid hydrogel exhibits outstanding osteogenic potential both in vitro and in vivo. Importantly, it is the first time that a key epigenetic regulator of ten‐eleven translocation 2 (Tet2) is discovered to significantly elevate the continuously active the WNT/β‐catenin through Tet2/HDAC1/E‐cadherin/β‐catenin signaling cascade, thereby promoting PDLSCs osteogenesis. This work represents a general strategy to design the hydrogels with customized networks and biomimetic mechanics, and illustrates underlying osteogenic mechanisms that will extend the design rationales for high‐functional biomaterials in tissue engineering. [ABSTRACT FROM AUTHOR]

It is a textbook knowledge that protein photoluminescence stems from the three aromatic amino acid residues of tryptophan(Trp), tyrosine (Tyr), and phenylalanine (Phe), with predominant contributions from Trp. Recently, inspired by the intrinsic emission of nonaromatic amino acids and poly(amino acids) in concentrated solutions and solids, we revisited protein light emission using bovine serum albumin (BSA) as a model. BSA is virtually nonemissive in dilute solutions (≤0.1 mg mL−1), but highly luminescent upon concentration or aggregation, showing unique concentration‐enhanced emission and aggregation‐induced emission (AIE) characteristics. Notably, apart from well‐documented UV luminescence, bright blue emission is clearly observed. Furthermore, persistent room‐temperature phosphorescence (p‐RTP) is achieved even in the amorphous solids under ambient conditions. This visible emission can be rationalized by the clustering‐triggered emission (CTE) mechanism. These findings not only provide an in‐depth understanding of the emissive properties of proteins, but also hold strong implications for further elucidating the basis of tissue autofluorescence. [ABSTRACT FROM AUTHOR]

Construction of simple and efficient protein adsorption materials is extremely vital to satisfy the requirements of highly purified proteins in biopharmaceutical and biotechnological industries, yet remains challenging. Herein, a cost‐effective strategy to develop seaweed‐derived nanofibrous membranes (NFM) for ultrahigh protein adsorption is reported. Synergistic regulation by cosolvent of ethanol, nonionic surfactants of Triton X‐100, and polyethylene oxide (PEO5000k) is employed to realize electrospinning of seaweed‐derived sodium alginate (SA) nanofibers with higher alginate content of 98 wt% to date, and following water washing easily generates SA nanofibrous membranes (SA‐NFM) with excellent morphology. Benefiting from the nanoscale merit of large specific surface area and tortuously porous microstructure, SA‐NFM exhibit a high actual capacity of 1235 mg g−1 toward lysozyme, which far exceeds maximum value for the reported 2D membrane materials (710 mg g−1) and is about 20 times that of commercial membranes adsorbents (51 mg g−1). Higher dynamic capacity of 805 mg g−1 (gravity driven) is also realized to meet the demand of practical application. The SA‐NFM also possess outstanding reversibility and unique selectivity toward specific proteins. Herein, SA‐NFM represent a perfect candidate for next‐generation protein absorbents for fast and efficient bioseparation. [ABSTRACT FROM AUTHOR]

Peroxynitrite (ONOO−) is attracting increasing attention due to its involvement in multiple facets of pathophysiological events. Reliable and accurate detection of biogenic ONOO− will definitely benefit for disentangling its complex functions in living systems. Responsive probe-based fluorescence imaging has become an efficient approach to achieve this goal. To date, plenty of fluorescence probes have been developed for ONOO− bioimaging in living cells and/or in vivo. To highlight the recent advances, this review emphasizes the design strategy, reaction mechanism, and bioimaging applications of ONOO− fluorescence probes developed in recent years. Finally, the challenges and future development trends of ONOO− fluorescence probes are discussed. We believe that this review will provide deep insight and guidance for the fabrication of novel ONOO− fluorescence probes with satisfactory performance, boosting the elucidation of ONOO− biochemistry and biofunction, and promoting the diagnosis, prevention, and therapy of ONOO−-related diseases. • An overview of responsive fluorescence probes for peroxynitrite was presented. • Design strategy, reaction mechanism, and bioimaging applications of fluorescence probes for peroxynitrite were reviewed. • Potential challenges and perspectives in responsive probes for peroxynitrite were highlighted. [ABSTRACT FROM AUTHOR]

Hydrogels are extracellular-matrix-like biomimetic materials that have wide biomedical applications in tissue engineering and drug delivery. However, most hydrogels cannot simultaneously fulfill the mechanical and cell compatibility requirements. In the present study, we prepared a semi-interpenetrating network composite gel (CG) by incorporating short chain chitosan (CS) into a covalent tetra-armed poly(ethylene glycol) network. In addition to satisfying physicochemical, mechanics, biocompatibility, and cell affinity requirements, this CG easily encapsulated acetylsalicylic acid (ASA) via electrostatic interactions and chain entanglement, achieving sustained release for over 14 days and thus promoting periodontal ligament stem cell (PDLSC) proliferation and osteogenic differentiation. In vivo studies corroborated the capacity of PDLSCs and ASA-laden CG to enhance new bone regeneration in situ using a mouse calvarial bone defect model. This might be attributed to PDLSCs and host mesenchymal stem cells expressing monocyte chemoattractant protein-1, which upregulated M2 macrophage recruitment and polarization in situ , indicating its appealing potential in bone tissue engineering., Competing Interests: The authors declare no conflict of interest., (© 2021 The Authors.)

Nonconventional biomacromolecular luminogens have attracted extensive interest due to their fundamental importance and potential applications in diverse areas. To explore novel luminogens and, moreover, to gain deeper insights into their emission mechanism, we study the emission behaviors of sodium alginate (SA), a natural anionic polysaccharide composed of mannuronic (M) and guluronic acids (G). We find that the luminescence from aqueous SA solutions exhibits distinct concentration enhanced emission and aggregation-induced emission (AIE) characteristics. Meanwhile, the ratio of M/G also matters. Rheological measurements reveal the distinct regimes of the solutions, which are consistent with the observed emission, indicative of strong association between the chain entanglement and emission. Moreover, we observe persistent room temperature phosphorescence (RTP) in the amorphous SA solids, which is a rare case even in pure organic aromatic luminogens. Such unique emission can be remarkably enhanced via coordination with Ca 2+ ions. These emission behaviors can be well rationalized by the clustering-triggered emission (CTE) mechanism. Namely, the emission is caused by the electron cloud overlap due to the clustering of oxygen atoms and carboxylate units, together with conformation rigidification. Owing to its biocompatibility, intrinsic emission, and, moreover, persistent RTP, SA shows great potential for anticounterfeiting, encryption, intracellular imaging, and so on.