Latest ArticlesBone-related diseases resulting from accidents, illnesses, and injuries have become increasingly common in recent years. Treating these conditions poses significant challenges, including prolonged recovery times, high costs, and unpredictable outcomes, which can lead to complications such as infections and reduced muscle strength. Although autologous bone transplantation is regarded as the "gold standard" for addressing bone diseases, its application is often limited by complications at the donor site and the risk of infection. This underscores the urgent need to explore alternatives to autogenous bone transplantation. In response, a range of biomaterials for bone repair have been developed, with metal-based biomaterials emerging as effective adjuncts that enhance and optimize the repair and regeneration of bone tissue. These materials can actively influence the bone repair process through mechanisms such as inductive osteogenesis, immunomodulation, and pro-angiogenesis. This review begins by highlighting the biological effects of metal-based biomaterials, followed by a comprehensive overview of their macro- and micro-scale classifications and applications for treating various bone diseases. Finally, the review addresses future directions and challenges associated with the use of metal-based biomaterials in bone repair, aiming to propose promising strategies for the treatment of bone-related diseases.
In this work, the spin-orbit charge transfer intersystem crossing (SOCT-ISC) mechanism is introduced into the near-infrared and highly photon-capturing heptamethine cyanine (Cy7) class to construct photosensitizer (PS) for photodynamic therapy (PDT) of tumor. The target PS AN–Cy7 shows an obviously improved singlet oxygen (1O2) quantum yield than the Food and Drug Administration (FDA)-approved indocyanine green (ICG) under 750 nm low-power photoirradiation (30 mW/cm2) while retaining strong fluorescence at ~805 nm. Importantly, the PS forms a 2:1 dye-human serum albumin (HSA) nanocomplex, ensuring its strong accumulation and retention at tumor site (up to five days) post intravenous injection. After a single PDT treatment, the nanocomplex almost completely ablates primary tumor while triggering an antitumor immune response to suppress the growth of distant tumors. Overall, the nanocomplex overcomes many shortcomings of clinically used PSs, thus being promising for future clinical translation.
Sirtuin 2 (SIRT2) is one of the key members of sirtuins family that plays important role in regulating many physiological processes. Recent evidences have revealed that SIRT2 is associated with the development, progression and metastasis of ovarian cancer. In this study, guided by an in-depth analysis of the clinical characteristics of the expression pattern of SIRT2 in ovarian cancer patients, the first SIRT2-targeted hydrophobic tagging (HyT) degraders have been developed. These acyl thiourea degraders exhibited remarkable anti-proliferative activity in several ovarian cancer cells. Among them, the most effective compound Ⅱ-6 exhibited excellent anti-tumor activity both in vitro and in vivo (half maximal inhibitory concentration (IC50) = 0.002 ± 0.001 µmol/L). In addition, Ⅱ-6 was found to effectively suppress cancer cell proliferation and migration, as well as cell cycle arrest and apoptosis. Moreover, further investigation revealed that compound Ⅱ-6 indirectly induced DNA damage through the H4K20me2/53BP1 pathway by degradation of SIRT2. The study not only exemplifies the advantage of the novel HyT degradation strategy but also prove the great potential of SIRT2 as a promising target for drug development of ovarian cancer.
The vast majority of lanthanide-doped nanoparticles (LnNPs) exhibit a single mode of upconversion luminescence (UCL) or downshifting luminescence (DSL) for photodynamic therapy (PDT) or diagnostic imaging of tumors, respectively. In order to achieve both UCL and DSL, it is often necessary to dope the luminescent ions in different shell layers to prevent their luminescence quenching, resulting in tedious synthesis steps. Herein, upconversion-downshifting nanoparticles (UDNPs) co-doped with Er3+ and Ho3+ enable the simultaneous dual-wavelength DSL for in vivo near-infrared (NIR)-Ⅱ fluorescence imaging of tumors. On the other hand, the UCL of UDNPs could activate merocyanine photosensitizers (MC 540), resulting in the generation of reactive oxygen species (ROS) and the achievement of PDT. Importantly, Au NPs with glucose oxidase-like properties could consume glucose and promote H2O2 accumulation in tumor cells. Au-catalyzed UDNPs modified with Fe-tannic acid (FeTA) (UDNP-MC/Au-FeTA) could not only enhance the effect of PDT but also realize chemodynamic therapy (CDT) by reacting with Fe2+ generated from slightly acidic decomposition of FeTA to accelerate hydroxyl radical (•OH) generation. The combination of long- and short-acting dual-dynamic therapy could mutually reinforce and compensate for the lack of therapeutic efficacy resulting from luminescence quenching caused by co-doping luminescent ions. Therefore, UDNP-MC/Au-FeTA guided by NIR-Ⅱ fluorescence imaging could achieve efficient synergistic dual-dynamic therapy of tumors through differentially expressed genes associated with apoptosis and oxidative stress-related pathways. NIR-Ⅱ fluorescence imaging diagnostic and dual-dynamic therapeutic strategy, which employs Au-catalyzed lanthanide co-doped UDNPs represents a dexterous design concept for promising anti-tumor applications.
Accurate cancer diagnosis is essential for fluorescence surgical navigation to eliminate tumors. Second near-infrared (NIR-Ⅱ, 1000–1700 nm) probes with aggregation-induced emission (AIE) nature possess bright fluorescence in a biological environment. However, due to the large particle sizes, NIR-Ⅱ AIE probes usually lead to high liver retention, which is not conducive to tumor enrichment. Therefore, this work constructs a novel amphiphilic NIR-Ⅱ AIE molecule, TTB-PEG1000, which can self-assemble into ultra-small fluorescent dots (7 nm) in the aqueous environment with a maximum emission at 1080 nm. Based on its excellent photostability, morphological stability, and biocompatibility, TTB-PEG1000 shows a desirable definition of angiography capability with high signal-to-background (SBR) in the NIR-Ⅱ AIE window over 1300 nm. Notably, treatment with TTB-PEG1000 in the glioma-tumor mice results in a significant enhancement of the accumulation in the tumor and reduction of the retention in the liver, in which the fluorescent ratio between tumor and liver (T/L) is 32-fold higher than that of their contrast (TTB-COOH NPs) prepared by the nanoprecipitation method. This work is the first report of an amphiphilic AIE molecule with NIR-Ⅱ maximum emission and sub-10 nm size, which will promise for preclinical applications and inspire further exploration of NIR-Ⅱ fluorophores for advanced biomedical imaging.
Penispirolactam (1) and penipyrroloindole (2), two highly modified paspaline-type indole diterpenoids (IDTs), along with three new (3–5) and two known (6 and 7) paspaline-type IDTs were obtained from the endophytic fungus Penicillium janthinellum H-6 guided by liquid chromatography-mass spectrometry (LC-MS)-based molecular network. Architecturally, penispirolactam (1) possesses a unique octacyclic skeleton (6/5/6/6/5/6/6/6) with a spiro core formed by the integration of a C6–C2 unit with the indole moiety, and penipyrroloindole (2) represents a rearranged octacyclic skeleton (6/5/6/5/5/6/6/6) with a pyrrolo[1,2-a]indole core fragment. Their structures, including absolute configurations, were established by detailed spectroscopic analysis, gauge-independent atomic orbital (GIAO) 1D nuclear magnetic resonance (NMR) (DP4+) calculation protocol, and electronic circular dichroism (ECD) calculation method. The plausible biosynthetic pathway of compounds 1 and 2 was also speculated. Additionally, the anti-hepatic fibrosis activity of all compounds was explored, and it was found that 1 could exert its effects by inhibiting the transforming growth factor-β (TGF-β)/Smad signaling pathway without cytotoxicity.
Up to now, aggregation-induced emission (AIE) and aggregation-caused quenching (ACQ) have been widely used for fluorescence sensing, respectively. In our study, we covalently linked cyanine dye and 2-cyanobenzothiazole (CBT) to construct fluorescent probe NPCS. Through spectroscopic testing, it was found that the probe itself has both AIE and ACQ behavior. And these acts are borne by CBT and cyanine (CY) respectively. In this study, it was found that glutathione (GSH) showed aggregation and disaggregation effects on two parts of the probe, namely: low concentration of GSH mainly aggravated AIE, and high concentration of GSH disaggregated ACQ of the probe, both of which led to fluorescence enhancement effect and achieved turn-on fluorescence detection of high and low concentrations of GSH. Cysteine (Cys), on the other hand, can undergo a click reaction with the cyano group to generate a stable fluorescent signal. Since Cys does not have the ability to disaggregate, the probe can achieve non-competitive discrimination detection of Cys and GSH. Real-time discriminatory detection of changes in Cys and GSH levels was demonstrated in living cells. The results of this study provide a new perspective for the development of emerging recognition mechanisms and multi-functionality of probes.
As fundamental chemicals, alkynes have been pivotal in synthesizing numerous value-added compounds. Direct manipulation of alkynes offers rapid access to diverse chemical spaces. Cleaving the alkyne triple bond has traditionally required harsh conditions due to its high bond dissociation energy. Here, we present a manganese-catalyzed electrochemical nitrogenation method for the direct cleavage of C≡C bonds, efficiently generating various nitriles under mild conditions. This reaction demonstrates extensive functional group tolerance and eliminates the need for stoichiometric chemical oxidants. CV experiments verified the role of Mn catalysis, and the N3 radical intermediate was confirmed by EPR spectroscopy. Our synthetic protocol provides a promising and versatile alternative for constructing nitrogen-containing compounds, potentially transforming approaches in chemical synthesis
Amino acids are the building blocks of proteins and various bioactive molecules. Fluorination is a key strategy in medicinal chemistry, making the development of new and efficient methods for fluorinating amino acids highly desirable. While many fluorination reagents have been developed, their application on amino acid frameworks remains limited. In this study, we demonstrate that ethyl 3-bromo-2-((diphenylmethylene)amino)-3,3-difluoropropanoate is an effective gem-difluoroalkenes precursor for constructing a library of monofluoroolefin amino acids via a Pd-catalyzed cross-coupling reaction.
Orthogonal molecular orbitals (MOs) of donor-acceptor (D-A) pairs favor the spin-orbit charge transfer intersystem crossing (SOCT-ISC) transition, and herein 2-anthryl asymmetric aza-boradiazaindacene (aza-BODIPY) (AH-BDP) was designed and prepared. According to the X-ray crystallography, the steric hindrance in orthogonal molecule AH-BDP results in a large dihedral angle between the two MO planes. Since low ΔEst prefers to undertake ISC and efficiently produce reactive oxygen species (ROS), the calculated ΔEst for AH-BDP is 0.757 eV, significantly smaller than that of the aza-BDOPY without anthryl group DH-BDP (1.052 eV). AH-BDP as a heavy-atom-free photosensitizer not only produced the singlet oxygen, but also possessed photothermal conversion efficiency. Self-assembly AH-BDP nanoparticles (NPs) could efficiently induce HCT116 cells elimination in nude mice through ROS/heat-mediated pathways.
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