NQO1-activated multifunctional theranostic probe for imaging-guided mitochondria-targeted photodynamic therapy and boosting immunogenic cell death

NAD(P)H: quinine oxidoreductase (NQO1) is overexpressed in many types of cancer cells, and have been used as a biomarker for cancer diagnosis and targeted therapy. The development of activatable theranostic agents is highly desirable for precise cancer diagnosis and therapy. Herein, a NQO1-activated near-infrared multifunctional theranostic probe I-HCy-Q is successfully developed for imaging guided photodynamic therapy. The NIR fluorescence (λex/em = 685/703 nm) and capacity of reactive oxygen species generation are sensitive controllable by the level of NQO1, the linear detection range of NQO1 and limit of detection are 0.05-1.5 μg/mL and 5.66 ng/mL, respectively. On the one hand, I-HCy-Q can monitor the activity of NQO1 and distinguish the NQO1 positive cancer cells; on the other hand, the capacity of mitochondria-targeted photodynamic therapy makes I-HCy-Q an effective inducer of apoptosis and immunogenic cell death. Attribute to its complementary advantages, I-HCy-Q holds potential for the imaging and treatment of tumors in complex organisms.

Flexible neural probes: a review of the current advantages, drawbacks, and future demands

Brain diseases affect millions of people and have a huge social and economic impact. The use of neural probes for studies in animals has been the main approach to increasing knowledge about neural network functioning. Ultimately, neuroscientists are trying to develop new and more effective therapeutic approaches to treating neurological disorders. The implementation of neural probes with multifunctionalities (electrical, optical, and fluidic interactions) has been increasing in the last few years, leading to the creation of devices with high temporal and spatial resolution. Increasing the applicability of, and elements integrated into, neural probes has also led to the necessity to create flexible interfaces, reducing neural tissue damage during probe implantation and increasing the quality of neural acquisition data. In this paper, we review the fabrication, characterization, and validation of several types of flexible neural probes, exploring the main advantages and drawbacks of these devices. Finally, future developments and applications are covered. Overall, this review aims to present the currently available flexible devices and future appropriate avenues for development as possible guidance for future engineered devices.

Covalent inhibition of epidermal growth factor receptor using a long-lived iridium(III)-afatinib probe

The overexpression and overactivation of epidermal growth factor receptor (EGFR) are frequently observed in human cancers, including squamous cell carcinoma and adenocarcinoma. In this study, a covalent EGFR probe was developed by conjugating afatinib to an iridium(III) scaffold. Complex 1 showed enhanced luminescence in living epidermoid squamous carcinoma A431 cells compared to other cell lines, via engaging EGFR as confirmed via CETSA and knockdown experiments. Moreover, complex 1 inhibited downstream targets of EGFR in cellulo with repression persisting after removal of the complex, indicating an irreversible mode of inhibition. Finally, complex 1 showed potent antiproliferative activity against A431 cells with comparable potency to afatinib alone. To our knowledge, complex 1 is the first EGFR covalent inhibitor based on an iridium scaffold reported in the literature, with the potential to be further explored as a theranostic agent in the future.

Multifunctional nanocarrier with self-catalytic production of nitric oxide for photothermal and gas-combined therapy of tumor

Single treatment often faces the problem that it cannot completely eradicate tumor and inhibit the tumor metastasis. In order to overcome this shortcoming, multi-modal tumor treatment has attracted widespread attention. In the present article, based on ascorbyl palmitate (PA) and l-arginine (l-Arg), a multifunctional nanocarrier is designed for synergetic treatment of tumor with photothermal and nitric oxide (NO) gas therapy. Firstly, PA and l-Arg were self-assembled to form novel functional micelles, PL, with high biosafety using electrostatic interaction and hydrogen bonding. The functional micelles could self-catalyze to produce NO at the tumor site. Then, Ag₂S quantum dots having fluorescence imaging and photothermal properties were encapsulated to obtain the nanocarrier, A@PL. The results show that A@PL had a hydrated size of around 78 nm and presented good stability within 30 d. Moreover, in vitro studies indicate that it was efficient with regards to NO self-generating capacity, whereas the photothermal conversion efficiency was as high as 34% under near-infrared light irradiation. The cytotoxicity results show that, when the concentration of A@PL was as high as 2 mM, the survival rate of 3 T3 cells was still 78.23%, proving that the probe has good safety characteristics. Fluorescence imaging results show that its maximum enrichment can be achieved at the tumor site after tail vein injection for 3 h, and out of the body after 24 h, indicating good internal circulation. The in vivo studies show that the rate of inhibition of tumor using the nanocarrier was as high as 98%, and almost overcame the problem of tumor recurrence caused by single treatment, thus presenting a significant tumor treatment effect. This new multifunctional nanocarrier with self-catalytic production of NO provides a new idea for the efficient treatment of tumors.

Multifunctional N,S co-doped carbon dots for sensitive probing of temperature, ferric ion, and methotrexate

In this paper, we have presented a facile method to fabricate nitrogen and sulfur co-doped carbon dots (N,S-CDs) for blood methotrexate (MTX) sensing applications. The N,S-CDs with quantum yield up to 75% were obtained by one-step hydrothermal carbonization, using reduced glutathione and citric acid as the precursors. With this approach, the formation and the surface passivation of N,S-CDs were carried out simultaneously, resulting in intrinsic fluorescence emission. Owing to their pronounced temperature dependence of the fluorescence emission spectra, resultant N,S-CDs can work as versatile nanothermometry devices by taking advantage of the temperature sensitivity of their emission intensity. In addition, the obtained N,S-CDs facilitated high selectivity detection of Fe³⁺ ions with a detection limit as low as 0.31 μM and a wide linear range from 3.33 to 99.90 μM. More importantly, the added MTX selectively led to the fluorescence quenching of the N,S-CDs. Such fluorescence responses were used for well quantifying MTX in the range of 2.93 to 117.40 μM, and the detection limit was down to 0.95 μM. Due to "inert" surface, the N,S-CDs well resisted the interferences from various biomolecules and exhibited excellent selectivity. The proposed sensing system was successfully used for the assay of MTX in human plasma. Due to simplicity, sensitivity, selectivity, and low cost, it exhibits great promise as a practical platform for MTX sensing in biological samples. Graphical Abstract.