Furthermore, the preliminary in vivo study shows that the Alg/CS-Sr composite hydrogel facilitates the repair of cartilage in rabbit cartilage defect. Taken together, it is indicated that the Alg/CS-Sr composite hydrogel might be a promising scaffold to promote the repair of cartilage defects.Diketopyrrolopyrrole (DPP) based organic molecules have drawn significant research attention as phototheranostic agents. Herein, based on thieno[3,2-b]thienyl-DPP (TT-DPP), a near-infrared small molecule photosensitizer diethyl 3,3′-((((2,5-bis(2-decyltetradecyl)-3,6-dioxo-2,3,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1,4-diyl)bis(thieno[3,2-b]thiophene-5,2-diyl))bis-(4,1-phenylene))bis(7-bromo-10H-phenothiazine-10,3-diyl))(2E,2’E)-diacrylate (PDBr), with a high singlet oxygen (1O2) quantum yield of 67%, was developed. After nano-precipitation, the hydrophilic PDBr NPs present an encouraging photothermal conversion efficiency of 35.7% and excellent fluorescence/infrared-thermal imaging performance. In vitro studies disclosed the high phototoxicity but low dark cytotoxicity of PDBr NPs to tumor cells. Furthermore, PDBr NPs can effectively impede the tumor growth without noticeable side effects in living mice through imaging-guided synergistic photothermal/photodynamic therapy. Therefore, PDBr NPs could be a promising nanotheranostic agent for imaging-guided synergistic photothermal and photodynamic therapy in the clinic.Damaged cartilage does not readily heal and often requires surgical intervention that only modestly improves outcomes. A synthetic material that could be injected and covalently crosslinked in situ to form a bioactive, mechanically robust scaffold that promotes stem cell chondrogenic differentiation holds promise for next-generation treatment of cartilage lesions. Here, Johnson-Claisen rearrangement chemistry was performed on graphene oxide (GO) to enable functionalization with a primary amine covalently bound to the graphenic backbone through a chemically stable linker. The primary amines are used to form covalent crosslinks with chondroitin sulfate, an important component of cartilage that promotes regeneration, to form a hydrogel (EDAG-CS). The EDAG-CS system gels in situ within 10 min, and the graphenic component imparts improved mechanical properties, including stiffness (320% increase) and toughness (70% increase). EDAG-CS hydrogels are highly porous, resistant to degradation, and enable the growth of human mesenchymal stem cells and their deposition of collagen matrix. This system has potential to improve clinical outcomes of patients with cartilage damage.Alzheimer’s disease (AD) is one of the most serious health threats in our aging society. The major pathological feature of AD is excessive extracellular aggregation of β-amyloid (Aβ) protein in the form of Aβ fibrils or plaques. The simultaneous detection of Aβ fibrils and inhibition of their neurotoxicity is highly desirable for study of Alzheimer’s disease. Although various fluorophores have been developed for imaging of Aβ fibrils or plaques, they suffer from serious self-quenching at high concentration and a lack of neuroprotective functions. To tackle these challenges, we herein develop a multi-functional probe of Cur-N-BF2 with aggregation-induced emission (AIE) characteristics for light-up detection of Aβ fibrils and plaques, inhibition of Aβ fibrillation, disassembly of preformed Aβ fibrils, and protection of neuronal cells. The AIE-active theranostic probe is thus promising for study of Aβ fibrils and plaques in Alzheimer’s disease.Recent decades have witnessed the fast and impressive development of nanocarriers as a drug delivery system. Considering the safety, delivery efficiency and stability of nanocarriers, there are many obstacles in accomplishing successful clinical translation of these nanocarrier-based drug delivery systems. The gap has urged drug delivery scientists to develop innovative nanocarriers with high compatibility, stability and longer circulation time. Exosomes are nanometer-sized, lipid-bilayer-enclosed extracellular vesicles secreted by many types of cells. Exosomes serving as versatile drug vehicles have attracted increasing attention due to their inherent ability of shuttling proteins, lipids and genes among cells and their natural affinity to target cells. Attractive features of exosomes, such as nanoscopic size, low immunogenicity, high biocompatibility, encapsulation of various cargoes and the ability to overcome biological barriers, distinguish them from other nanocarriers. To date, exosome-based nanocarriers delivering small molecule drugs as well as bioactive macromolecules have been developed for the treatment of many prevalent and obstinate diseases including cancer, CNS disorders and some other degenerative diseases. Exosome-based nanocarriers have a huge prospect in overcoming many hindrances encountered in drug and gene delivery. This review highlights the advances as well as challenges of exosome-based nanocarriers as drug vehicles. Special focus has been placed on the advantages of exosomes in delivering various cargoes and in treating obstinate diseases, aiming to offer new insights for exploring exosomes in the field of drug delivery.Increasing attention has been given to the field of porous organic frameworks (POFs) due to their unique properties, outstanding performance, and broad applications. Given their extremely high surface area, ordered crystal structure, and ease of tailoring, POFs are promising candidates for gas adsorption and separation, catalysis, supercapacitors, chemosensors, and bio-related applications. Furthermore, their tunable pore size and high agent loading capacity make them promising candidates for drug delivery, whereas their ease of functionalization leads to target specificity and long blood circulation times, which are important properties in bioimaging. For biosensing applications, the pores and channels of POFs can accommodate target molecules and induce specific recognition. POFs can also be applied in phototherapy in combination with photosensitizers. Finally, POF-based artificial shells can encapsulate bioactive molecules and strengthen the resistance of cells to adverse environmental conditions. In this review, we will highlight the research progress of POF-based bio-related applications, including drug delivery, bioimaging, biosensing agents, as well as in phototherapy and artificial shells. Furthermore, the in vitro and in vivo toxicological studies of POFs are discussed as are the prospects and future research directions for POFs in bio-related applications.Elastomeric conductive hybrid hydrogels (ECHs) combining conducting polymers with elastomeric hydrogels have recently attracted interest due to their wide range of applications in bioelectronics such as wearable or implantable sensing devices. However, the conductivity of ECHs is typically compromised when conductive polymers are used as fillers in hydrogel networks because the inherent limitations of ECHs severely restrict their applicability. Here, we significantly improved the electrical conductivity of ECHs by using a bioinspired catechol derivative, dopamine (DA), as the dopant and mediator for the in situ polymerization of conducting polypyrrole (PPy) within the elastomeric hydrogel dual-networks. In general, ECHs prepared by conventional methods tend to form separate island structures of conductive polymers dispersed within porous hydrogel matrices. We found that a continuous conductive PPy network prepared using the DA mediator facilitated fast electron transfer within the ECHs, which showed good elastomeric mechanical properties, excellent biocompatibility and high force- or strain-responsiveness suitable for implantable strain-sensing applications.Correction for 'Iridium-catalyzed C-H amidation of s-tetrazines’ by Huan Xiong et al., Chem. Commun., 2020, DOI 10.1039/d0cc01647k.Herein, a simple all-in-one biosensor based on a DNA three-way junction has been constructed for in situ simultaneous detection of multiple miRNAs by competitive strand displacement. In our design, three oligonucleotides (Y1, Y2 and Y3) of a Y-type scaffold were extended at their 5′ ends by introducing three single-stranded recognition sequences with quenchers (BHQ1, BHQ2 and BHQ2), respectively. Subsequently, three reporter sequences labeled with different fluorophores (FAM, Cy3 and Cy5) were bound to the corresponding recognition sequences to form a multicolour DNA biosensor that gives self-quenched fluorescence. The biosensor can effectively enter into exosomes and then hybridize to the complementary miRNA targets to form longer duplexes and release the reporter sequences, thus activating the readable fluorescence signals for the simultaneous detection of multiple miRNAs in exosomes. As a proof of principle, miR-21, miR-27a and miR-375 were chosen as model targets because of their high expressions in breast cancer cells (MCF-7). Fluorescence signals of MCF-7 exosomes after being treated with the biosensor exhibited positive correlations to their concentrations and the limits of detection were determined to be 0.116 μg mL-1, 0.125 μg mL-1 and 0.287 μg mL-1 for exosomes by detecting three exosomal miRNAs (miR-21, miR-27a and miR-375), respectively. In contrast, there were no obvious correlations between fluorescence intensities and control MCF-10A exosome concentrations. Importantly, by testing multiple exosomal miRNAs using the biosensor in clinical serum samples, breast cancer patients can be effectively differentiated from healthy donors. Consequently, the developed biosensor demonstrates high potential as a routine bioassay for the multiplex quantification of exosomal miRNAs in clinical diagnosis.Luminescent Eu(iii) complexes with point-chiral phosphine oxide ligands, [Eu(hfa)3((R,R)-B2QPO)] (hfa hexafluoroacetylacetonato, B2QPO 2,3-bis(tert-butylmethylphosphine oxide)quinoxaline) and [Eu(hfa)3((R)-B3QPO)] (B3QPO 2-tert-butylmethylphosphine oxide-3-(di-tert-butylphosphineoxide)quinoxaline), are reported for the investigation of the electronic strain effect on the coordination sphere. Single crystal X-ray crystallography reveals the strong structural strain of the hfa ligands in [Eu(hfa)3((R,R)-B2QPO)]. The emission quantum yields of [Eu(hfa)3((R,R)-B2QPO)] in solution (55%) and solid (63%) are comparable to those of previously reported bright luminescent Eu(iii) complexes. The chiroptical properties of [Eu(hfa)3((R,R)-B2QPO)] and [Eu(hfa)3((R)-B3QPO)] were characterized using circular dichroism (CD) and circularly polarized luminescence (CPL) spectra. The dissymmetry factor of [Eu(hfa)3((R,R)-B2QPO)] was estimated to be 0.08. The chiroptical phenomena of the Eu(iii) complexes are closely related to their structural (geometry) and electronic (LMCT ligand-to-metal charge transfer) strains.A visible light-mediated, metal-free dehydrosulfurization reaction of thioamides to nitriles is described. This reaction features high yields, mild reaction conditions, and the use of a cheap organic dye as the photoredox catalyst and air as the oxidant.Theasinensin A (TSA) and theasinensin B (TSB), dimers of tea catechins produced during the processing of oolong tea and black tea, had superior inhibitory effects on α-glucosidase. However, the potential inhibitory mechanisms on α-glucosidase are still unclear. In the present study, TSA and TSB were chemically synthesized and purified, and their inhibitory effects on α-glucosidase and potential mechanisms were investigated. The results showed that TSA and TSB could inhibit the activity of α-glucosidase in a reversible and noncompetitive manner with IC50 values of 6.342 and 24.464 μg mL-1, respectively, which were much lower than that of acarbose. The fluorescence and circular dichroism spectra revealed that TSA and TSB could alter the microenvironment and the secondary structure of α-glucosidase, thereby decreasing the α-glucosidase activity. Molecular docking results indicated that both TSA and TSB had a strong binding affinity to α-glucosidase by hydrophobic interactions and hydrogen bonds. Moreover, the stronger inhibition of TSA on α-glucosidase might be related to the closer binding site to the active site pocket of α-glucosidase.