Mitochondria-targeted iridium(III) complexes encapsulated in liposome induce cell death through ferroptosis and gasdermin-mediated pyroptosis.

This paper unveils a novel perspective on synthesis and characterization of the ligand 5-bromo-2-amino-2'-(phenyl-1H-imidazo[4,5-f][1,10]phenanthroline) (BAPIP), and its iridium(III) complexes [Ir(PPY-)2(BAPIP)](PF6) (1a, with PPY- as deprotonated 2-phenylpyridine), [Ir(PIQ-)2(BAPIP)](PF6) (1b, piq- denoting deprotonated 1-phenylisoquinoline), and [Ir(BZQ-)2(BAPIP)](PF6) (1c, bzq- signifying deprotonated benzo[h]quinoline). Systematic evaluation of the cytotoxicity of 1a, 1b, and 1c across diverse cell lines encompassing B16, HCT116, HepG2, A549, HeLa, and LO2 using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Unexpectedly, compounds 1b and 1c demonstrated no cytotoxicity against the above cell lines. Motivated by the pursuit of heightened anti-proliferative potential, a strategic encapsulation approach yielded liposomes 1alip, 1blip, and 1clip. As expectation, 1alip, 1blip, and 1clip displayed remarkable anti-proliferative efficacy, particularly noteworthy in A549 cells, exhibiting IC50 values of 4.9 ± 1.0, 5.9 ± 0.1, and 7.6 ± 0.2 µM, respectively. Moreover, our investigation illuminated the mitochondrial accumulation of these liposomal entities, 1alip, 1blip, and 1clip, evoking apoptosis through the mitochondrial dysfunction mediated by reactive oxygen species (ROS). The ferroptosis was confirmed by decrease in glutathione (GSH) concentrations, the downregulation of glutathione peroxidase 4 (GPX4), increase of high mobility group protein 1 (HMGB1), and lipid peroxidation. Simultaneously, pyroptosis as another mode of cell death was undertaken. RNA-sequencing was employed to investigate intricate signalling pathways. In vivo examination provided tangible evidence of 1alip in effectively curbing tumor growth. Collectively, this study provides a multifaceted mode of cellular demise orchestrated by 1a, 1alip, 1blip, and 1clip, involving pathways encompassing apoptosis, ferroptosis, and pyroptosis.

Synthesis, characterization and irradiation enhances anticancer activity of liposome-loaded iridium(III) complexes.

Herein, we synthesized and characterized two novel iridium (III) complexes: [Ir(bzq)2(PPD)](PF6) (4a, with bzq = deprotonated benzo[h]quinoline and PPD = pteridino[6,7-f][1,10]phenanthroline-11,13-diamine) and [Ir(piq)2(PPD)](PF6) (4b, with piq = deprotonated 1-phenylisoquinoline). The anticancer efficacy of these complexes, 4a and 4b, was investigated using 3-(4,5-dimethylthiazole)-2,5-diphenltetraazolium bromide (MTT). Complex 4a exhibited no cytotoxic activity, while 4b demonstrated moderate efficacy against SGC-7901, A549, and HepG2 cancer cells. To enhance their anticancer potential, we explored two strategies: (I) light irradiation and (II) encapsulation of the complexes in liposomes, resulting in the formation of 4alip and 4blip. Both strategies significantly increased the ability of 4a, 4b to kill cancer cells. The cellular studies indicated that both the free complexes 4a, 4b and their liposomal forms 4alip and 4blip effectively inhibited cell proliferation. The cell cycle arrest analysis uncovered 4alip and 4blip arresting cell growth in the S period. Additionally, we investigated apoptosis and ferroptosis pathways, observing an increase in malondialdehyde (MDA) levels, a reduction of glutathione (GSH), a down-regulation of GPX4 (glutathione peroxidase) expression, and lipid peroxidation. The effects on mitochondrial membrane potential and intracellular Ca2+ concentrations were also examined, revealing that both light-activated and liposomal forms of 4alip and 4blip caused a decline in mitochondrial membrane potential and an enhancement in intracellular Ca2+ levels. In conclusion, these complexes and them encapsulated liposomes induce cell death through apoptosis and ferroptosis.

Removing endotoxin from plasmid samples by Triton X-114 isothermal extraction.

Triton X-114 temperature transition extraction has been considered to be a simple and cost-effective strategy to eliminate endotoxin from plasmid preparations. However, a repeated cooling-heating process may promote the degradation of plasmid DNA. Based on the finding that the cloud point of Triton X-114 solution increases substantially in the presence of small amounts of sodium dodecyl sulfate (SDS) and that electrolytes decrease the cloud point of Triton X-114-SDS solution drastically, we designed a Triton X-114 isothermal extraction method for removing endotoxin from plasmid samples and found that it has the same endotoxin removal efficiency when compared with the temperature transition extraction method.

Comparison of ultrasonic and CO2laser pretreatment methods on enzyme digestibility of corn stover.

To decrease the cost of bioethanol production, biomass recalcitrance needs to be overcome so that the conversion of biomass to bioethanol becomes more efficient. CO(2) laser irradiation can disrupt the lignocellulosic physical structure and reduce the average size of fiber. Analyses with Fourier transform infrared spectroscopy, specific surface area, and the microstructure of corn stover were used to elucidate the enhancement mechanism of the pretreatment process by CO(2) laser irradiation. The present work demonstrated that the CO(2) laser had potential to enhance the bioconversion efficiency of lignocellulosic waste to renewable bioethanol. The saccharification rate of the CO(2) laser pretreatment was significantly higher than ultrasonic pretreatment, and reached 27.75% which was 1.34-fold of that of ultrasonic pretreatment. The results showed the impact of CO(2) laser pretreatment on corn stover to be more effective than ultrasonic pretreatment.

Amplifying Free Radical Generation of AIE Photosensitizer with Small Singlet-Triplet Splitting for Hypoxia-Overcoming Photodynamic Therapy.

Type-I photodynamic therapy (PDT) with less oxygen consumption shows great potential for overcoming the vicious hypoxia typically observed in solid tumors. However, the development of type-I PDT is hindered by insufficient radical generation and the ambiguous design strategy of type-I photosensitizers (PSs). Therefore, developing highly efficient type-I PSs and unveiling their structure-function relationship are still urgent and challenging. Herein, we develop two phenanthro[9,10-d]imidazole derivatives (AQPO and AQPI) with aggregation-induced emission (AIE) characteristics and boost their reactive oxygen species (ROS) generation efficiency by reducing singlet-triplet splitting (ΔEST). Both AQPO and AQPI show ultrasmall ΔEST values of 0.09 and 0.12 eV, respectively. By incorporating electron-rich anisole, the categories of generated ROS by AIE PSs are changed from type-II (singlet oxygen, 1O2) to type-I (superoxide anion radical, O2•- and hydroxyl radical, •OH). We demonstrate that the assembled AQPO nanoparticles (NPs) achieve a 3.2- and 2.9-fold increase in the O2•- and •OH generation efficiencies, respectively, compared to those of AQPI NPs (without anisole) in water, whereas the 1O2 generation efficiency of AQPO NPs is lower (0.4-fold) than that of AQPI NPs. The small ΔEST and anisole group endow AQPO with an excellent capacity for type-I ROS generation. In vitro and in vivo experiments show that AQPO NPs achieve an excellent hypoxia-overcoming PDT effect by efficiently eliminating tumor cells upon white light irradiation with good biosafety.

Iron Self-Boosting Polymer Nanoenzyme for Low-Temperature Photothermal-Enhanced Ferrotherapy.

In this work, an iron self-boosting polymer nanoenzyme was prepared by using pyrrole-3-carboxylic acid as a monomer and iron as an oxidizing agent via a simple and one-step method [hereafter referred to as FePPy nanoparticles (NPs)]. In fact, researchers previously paid negligible attention on the iron element during the polymerization reaction of polypyrrole, thus the intrinsically catalytic functions and enzymatic activities of the high iron content (wt %: 21.11%) are ignored and not fully explored. As expected, results demonstrate that the as-synthesized FePPy NPs can decompose H2O2 to generate hydroxyl radicals (•OH) which exhibit enzyme characteristics, further inducing a nonapoptotic ferroptosis pathway. Moreover, the nanoenzyme shows impressive photothermal properties which can accelerate the Fenton reactions to enhance ferroptosis. The combined photothermal and ferroptosis therapy of FePPy NPs was found to have high efficacy. With the properties of easy synthesis, high efficacy, and good biocompatibility, the FePPy NPs are considered as potential agents for cancer treatments.

Controllable Cleavage of C-N Bond-Based Fluorescent and Photoacoustic Dual-Modal Probes for the Detection of H2S in Living Mice.

Hydrogen sulfide (H2S) has been recognized to influence a wide range of physiological and pathological processes. Its underlying molecular events, however, are still poorly understood. An activatable H2S probe for photoacoustic (PA) imaging is desirable to further explore the role of H2S in vivo. Nevertheless, only a few activatable PA probes for H2S detection have been reported. In particular, examples of dual-modal H2S probes with the combined advantages of fluorescence (high sensitivity and resolution) and PA imaging (deep penetration) are very rare. Herein the controllable cleavage of the C-N bond in nitrobenzoxadiazole (NBD) amine derivatives by H2S is presented for the first time. The cleavage reactivity was found to be accelerated by the introduction of an electron-withdrawing group. Through this strategy, a series of fluorescent and PA dual-modal probes (1-3) were developed for H2S detection. Among them, probe 3 shows a high fluorescence on-off response rate (k2 = 4.04 M-1 s-1) and excellent selectivity for H2S over other biothiols. Moreover, probe 3 can also work as an activatable PA H2S probe because of the significant shift of its absorption peak from 468 to 532 nm in the H2S reaction. Importantly, probe 3 demonstrates its capability for fluorescence and PA imaging of H2S in living cells and mice. These results indicate that the controllable cleavage of the C-N bond can serve as an efficient strategy for designing fluorescent and PA dual-modal H2S probes.

Self-targeting, zwitterionic micellar dispersants enhance antibiotic killing of infectious biofilms-An intravital imaging study in mice.

Extracellular polymeric substances (EPS) hold infectious biofilms together and limit antimicrobial penetration and clinical infection control. Here, we present zwitterionic micelles as a previously unexplored, synthetic self-targeting dispersant. First, a pH-responsive poly(ε-caprolactone)-block-poly(quaternary-amino-ester) was synthesized and self-assembled with poly(ethylene glycol)-block-poly(ε-caprolactone) to form zwitterionic, mixed-shell polymeric micelles (ZW-MSPMs). In the acidic environment of staphylococcal biofilms, ZW-MSPMs became positively charged because of conversion of the zwitterionic poly(quaternary-amino-ester) to a cationic lactone ring. This allowed ZW-MSPMs to self-target, penetrate, and accumulate in staphylococcal biofilms in vitro. In vivo biofilm targeting by ZW-MSPMs was confirmed for staphylococcal biofilms grown underneath an implanted abdominal imaging window through direct imaging in living mice. ZW-MSPMs interacted strongly with important EPS components such as eDNA and protein to disperse biofilm and enhance ciprofloxacin efficacy toward remaining biofilm, both in vitro and in vivo. Zwitterionic micellar dispersants may aid infection control and enhance efficacy of existing antibiotics against remaining biofilm.

[Study on the adsorption of endotoxin and proinflammatory cytokines with HB-H-7 resin in vitro].

OBJECTIVE: To study the efficacy and safety of adsorption of endotoxin and proinflammatory cytokines with HB-H-7 resin in vitro. METHODS: Static adsorption experiment: HB-H-7 resin was added into plasma of endotoxin-positive patients according to the ratio of 1;10. Then, they were put in a constant temperature water bath oscillator, and oscillated for 2 hours. Before and after the experiment, plasma endotoxin, proinflammatory cytokines, protein and electrolytes were detected, and the rate of 2-hour absorption was calculated. The experiment was repeated 10 times. Dynamic adsorption experiment: 5 ml resin was put into a self-made perfusion unit. Endotoxin-positive patients plasma (50 ml) was perfused for 2 hours. The flow rate of plasma was controlled at 4 ml/min with the infusion pump, and the plasma endotoxin was determined at 0, 30, 60 and 120 minutes after plasma hemoperfusion, and the absorption rates were calculated. The results were compared with static adsorption. The influence of temperature during adsorption was determined as follows. Perfusion method was similar with dynamic adsorption experiment. The perfusion units were either placed in a 37 centigrade water path or 25 centigrade (room temperature). Then, the plasma endotoxin was measured 2 hours after plasma perfusion, and the absorption rates were calculated. RESULTS: In static adsorption experiment, the plasma endotoxin and proinflammatory cytokines were significantly lower after adsorption with HB-H-7 resin adsorption (all P<0.05). The adsorption rates of endotoxin, tumor necrosis factor-alpha and interleukin-1, 6, 8 were 99.2%, 55.0%, 57.0%, 75.0%, 42.0%, respectively. Changes in protein were small (all P<0.05) , and there was no significant change in plasma electrolytes (all P>0.05). Dynamic adsorption rate was higher than that of static, but the differences were not significant (99.8% vs. 99.1%, P>0.05). There was no statistically significant difference between difference in temperature (37 centigrade vs. 25 centigrade, 99.8% vs. 99.9%, P>0.05). CONCLUSION: HB-H-7 resin effectively absorbs endotoxin and proinflammatory cytokines in vitro. Its adsorption rate for protein is lower, and it has no obvious effects on electrolytes.

Nanocarriers responsive to a hypoxia gradient facilitate enhanced tumor penetration and improved anti-tumor efficacy.

Because of their abnormal vasculature and the dense tumor extra-cellular matrix, solid tumors prevent the deep and uniform penetration of nanocarriers. Numerous studies have shown that nanocarriers with a positively charged surface exhibit enhanced tumor penetration. Therefore, a hypoxia responsive nanocarrier [responsive micelles (RMs)] was developed, which can gradually increase the positive surface charge by responding to hypoxia gradients, and eventually achieve deep penetration in tumors. The nanocarrier was composed of a poly(caprolactone) core and a mixed shell of poly(ethylene glycol) (PEG) and 4-nitrobenzyl chloroformate (NBCF)-modified polylysine (PLL). During the blood circulation, the NBCF-modified PLL was shielded by the PEG, which gave it the ability to inhibit its rapid removal by the immune system. After reaching the tumor, the hypoxia microenvironment triggered partial NBCF degradation that recovered the amine groups of PLL, leading to a remarkable change in the surface to a positively charged one that enabled the penetration of the nanocarrier into the tumor. As the nanocarrier penetrated into the interior of the tumor, the decrease in oxygen concentration led to the further degradation of the NBCF-modified PLL, resulting in the increase of the positive surface charge which further facilitated the deep penetration. The subsequent in vitro and in vivo experiments certified that RM/doxorubicin had a better penetration ability and improved inhibition efficacy on tumor tissues, which demonstrated its potential application in cancer therapy.

Deposition of doxorubicin in rats following administration of three newly synthesized doxorubicin conjugates.

We previously reported the synthesis of three DOX conjugates that represented different targeting vehicles and showed them to have antitumor activity both in vitro and in vivo. However, the relationships between the pharmacokinetics of these DOX conjugates and their chemical structures were not characterized. In the current study, free DOX derived from each of the conjugates was found at low levels in the rat circulatory system, with conjugated DOX being the major form. The two polyethylene glycol (PEG) conjugates slowly released DOX, and t1/2ß for total DOX from DOX-LNA, PEG-ami-DOX, and PEG-hyd-DOX was 5.79, 10.22, and 15.18 h, respectively. All three conjugates also deposited less DOX into normal organs than did an equivalent dose of free DOX, and the C(max) value of free DOX released by DOX-LNA, PEG-ami-DOX, and PEG-hyd-DOX was 32.5, 9.5, and 4.7 µg/g, respectively. Among the conjugates, the compound with an acid-labile bond between PEG and DOX exhibited the lowest free DOX deposition in healthy tissues, which should decrease the systemic toxicity of free DOX while allowing for tumor targeting by PEG.

[Interface bond and compatibility between Mark II machining ceramic and vita VM9 veneering porcelain].

OBJECTIVE: To investigate the interface bond and thermal compatibility between Mark II machining ceramic and Vita VM9 veneering porcelain. METHODS: A bar shaped specimen (30 mm x 15 mm x 1 mm in size) of Mark II block was prepared, with 0.5 mm-deep notch (vertical to the long axis of specimen) at the middle of the bottom surface. The upper surface was veneered with 0.3 mm VM9 dentin base porcelain. Then the specimen was fractured from the notching site and the fracture surface was examined under scanning electron microscope (SEM) and electron microprobe analyzer (EMPA) with electron beam of 1 microm in diameter. Another ten specimens (30 mm x 15 mm x 1.5 mm in size) were fabricated and the temperature of thermal shock resistance were tested. RESULTS: SEM observation showed tight bond between these two materials and EMPA results showed penetration of Al element from Mark II block into veneering porcelain and Ca element from veneering porcelain into Mark II block occurred after sintering baking. The average temperature of thermal shock resistance for specimens in this study was (194.0+/-10.3) degrees C. Cracks were mainly distributed in veneering porcelain. CONCLUSION: Chemical bond exists between the Mark II machining ceramic and Vita VM9 veneering porcelain, and there is good thermal compatibility between them.

[Application of all-ceramic laminates veneer with Vita VM9 in clinic].

OBJECTIVE: To evaluate the effects of all-ceramic veneers in clinic fabricated by computer aided design/computer aided manufacturing (CAD/CAM) system and veneered with Vita VM9. METHODS: 54 all-ceramic veneers were made for 12 patients. The patients were divided into three groups: Tetracycline staining group, fluorosis group and devitalization group. The color of patients' teeth was checked before and after laminates with Shade Eye. All-ceramic veneers was checked on the white background and abutment background. The value of L*, a* and b* were calculated to compare the color difference among 3 groups. The color, fitness and fracture of all-ceramic veneers were checked in clinic after restoration every 3 months. RESULTS: All-ceramic veneers as a replacement for discolored teeth showed good appearance. The substructures and veneers showed significant color difference between white background and abutment background in tetracycline staining group and devitalization group, but there was no significant color difference in fluorosis group. All veneers had good esthetic effect, excellent marginal fit, good gingival and adjacent condition. The fracture was not found in clinic. CONCLUSION: The effects of all-ceramic veneers were perfect in color, fitness and stability to fracture. Fluorosis teeth is the best indication for all-ceramic veneers. To tetracycline teeth and devital teeth, the fundic porcelain with deep color should be chosen, or an opaquing material be applied as fundus in all-ceramic veneers repairing.