Bifunctional Cascading Nanozymes Based on Carbon Dots Promotes Photodynamic Therapy by Regulating Hypoxia and Glycolysis.

Photodynamic therapy (PDT) still faces great challenges with suitable photosensitizers, oxygen supply, and reactive oxygen species (ROS) accumulation, especially in the tumor microenvironment, feathering hypoxia, and high glucose metabolism. Herein, a carbon dots (CDs)-based bifunctional nanosystem (MnZ@Au), acting as photosensitizer and nanozyme with cascading glucose oxidase (GOx)- and catalase (CAT)-like reactivity, was developed for improving hypoxia and regulating glucose metabolism to enhance PDT. The MnZ@Au was constructed using Mn-doped CDs (Mn-CDs) as a core and zeolitic imidazolate framework-8 (ZIF-8) as a shell to form a hybrid (MnZ), followed by anchoring ultrasmall Au nanoparticles (AuNPs) onto the surface of MnZ through the ion exchange and in situ reduction methods. MnZ@Au catalyzed glucose consumption and oxygen generation by cascading GOx- and CAT-like nanozyme reactions, which was further enhanced by its own photothermal properties. In vitro and in vivo studies also confirmed that MnZ@Au greatly improved CDs penetration, promoted ROS accumulation, and enhanced PDT efficacy, leading to efficient tumor growth inhibition in the breast tumor model. Besides, MnZ@Au enabled photoacoustic (PA) imaging to provide a mapping of Mn-CDs distribution and oxygen saturation, showing the real-time catalytic process of MnZ@Au in vivo. 18F-Fluorodeoxyglucose positron emission tomography (18F-FDG PET) imaging also validated the decreased glucose uptake in tumors treated by MnZ@Au. Therefore, the integrated design provided a promising strategy to utilize and regulate the tumor microenvironment, promote penetration, enhance PDT, and finally prevent tumor deterioration.

Magnetic Resonance Imaging Quantification of the Liver Iron Burden and Volume Changes Following Treatment With Thalidomide in Patients With Transfusion-Dependent ß-Thalassemia.

Clinical trials have indicated that thalidomide could be used to treat thalassemia, but evidence of changes in liver iron burden and liver volume during thalidomide treatment is lacking. This study aimed to evaluate the liver iron burden and volume changes following thalidomide treatment in patients with transfusion-dependent ß-thalassemia. A total of 66 participants with transfusion-dependent ß-thalassemia were included in this prospective cohort study between January 2017 and December 2020. Patients were treated with thalidomide (150-200 mg/day) plus conventional therapy. Liver volume, liver R2*, and hepatic muscle signal ratio (SIR)_T1 and SIR_T2 were measured with magnetic resonance imaging (MRI), and serum ferritin, hemoglobin, erythrocyte and platelet counts, and liver function were measured at baseline and at the 3rd and 12th months. Adverse events were also noted. Patients showed progressive increase in hemoglobin, erythrocyte, platelet count, SIR_T1, and SIR_T2 during the 12-months follow up. Serum ferritin, R2*, and liver volume progressively decreased during the follow up. The R2* value had a significantly positive correlation with serum ferritin, and SIR_T1 and SIR_T2 had a significantly negative correlation with serum ferritin. No serious adverse events were observed. This study showed that thalidomide could potentially be used to successfully treat patients with transfusion-dependent ß-thalassemia; the liver iron burden and liver volume could be relieved during treatment, and the MRI-measured R2*, SIR_T1, and SIR_T2 may be used to noninvasively monitor liver iron concentration.

Safety and efficacy of thalidomide in patients with transfusion-dependent ß-thalassemia: a randomized clinical trial.

Thalidomide induces γ-globin expression in erythroid progenitor cells, but its efficacy on patients with transfusion-dependent ß-thalassemia (TDT) remains unclear. In this phase 2, multi-center, randomized, double-blind clinical trial, we aimed to determine the safety and efficacy of thalidomide in TDT patients. A hundred patients of 14 years or older were randomly assigned to receive placebo or thalidomide for 12 weeks, followed by an extension phase of at least 36 weeks. The primary endpoint was the change of hemoglobin (Hb) level in the patients. The secondary endpoints included the red blood cell (RBC) units transfused and adverse effects. In the placebo-controlled period, Hb concentrations in patients treated with thalidomide achieved a median elevation of 14.0 (range, 2.5 to 37.5) g/L, whereas Hb in patients treated with placebo did not significantly change. Within the 12 weeks, the mean RBC transfusion volume for patients treated with thalidomide and placebo was 5.4 ± 5.0 U and 10.3 ± 6.4 U, respectively (P < 0.001). Adverse events of drowsiness, dizziness, fatigue, pyrexia, sore throat, and rash were more common with thalidomide than placebo. In the extension phase, treatment with thalidomide for 24 weeks resulted in a sustainable increase in Hb concentrations which reached 104.9 ± 19.0 g/L, without blood transfusion. Significant increase in Hb concentration and reduction in RBC transfusions were associated with non ß0/ß0 and HBS1L-MYB (rs9399137 C/T, C/C; rs4895441 A/G, G/G) genotypes. These results demonstrated that thalidomide is effective in patients with TDT.

Variability in Primary Care Physician Attitudes Toward Medicaid Work Requirement Exemption Requests Made by Patients With Depression.

Importance: Medicaid work requirements seek to promote health and personal responsibility but can also jeopardize health care access. Physicians have a central function in assisting patients with exemption requests, but it is unclear how their role affects patient welfare, professionalism, and the ethical and legal justification of programs. Objective: To understand the degree of variability in physician response to assist patients with depression in receiving a Medicaid work requirement exemption. Design Setting and Participants: We conducted a mailed survey experiment among practicing primary care physicians in the first 4 approved states (Arkansas, Kentucky, Indiana, New Hampshire) in July and October of 2019. We report response, cooperation, refusal, and contact rates in line with American Association for Public Opinion Research (AAPOR) standards. Exposures: In each state, we used an experimental factorial design to randomize recipients to 1 of 4 patient clinical scenarios. Main Outcomes and Measures: The primary outcome was the indicator of willingness to assist a patient reporting depression with an exemption. Results: We received 715 responses (overall AAPOR response rate: 21%; cooperation rate: 84%; refusal rate: 4%; contact rate: 25%). Respondents' mean (SD) age was 54 (12) years; mean (SD) time since graduation, 26 (12) years; 435 (61%) identified as male; 177 as Democrat (25%); 156 as Republican (22%); 197 as Independent/other (28%); and 185 as declined/unknown (26%); the mean (SD) share of Medicaid patients was 29% (21%). We found that 97 of 387 physicians (25%) would offer assistance even when state policy would not support an exemption, and 170 of 315 (54%) would not offer assistance when regulations would require this. Moreover, 49 of 245 respondents (20%) who deemed an exemption appropriate indicated that they would not assist. State, administrative effort, political affiliation, and perceived appropriateness were statistically associated with the odds of assisting with an exemption. Conclusions and Relevance: In this survey study of primary care physicians, we found substantial variation regarding willingness to assist patients qualifying for a work requirement exemption where none should exist. Insofar as work requirements are implemented again, it is critical to proactively identify measures to ensure that patients qualifying for exemptions are not put at risk due to either the burdensomeness of exemption procedures, or physicians' political or personal views.

Virus-inspired and mimetic designs in non-viral gene delivery.

Virus-inspired mimics for nucleic acid transportation have attracted much attention in the past decade, especially the derivative microenvironment stimuli-responsive designs. In the present mini-review, the smart designs of gene carriers that overcome biological barriers and realize an efficient delivery are categorized with respect to the different "triggers" provided by tumor cells, including pH, redox potentials, ATP, enzymes and reactive oxygen species. Some dual/multi-responsive gene vectors have also been introduced that show a more precise and efficient delivery in the complicated environment of human body. In addition, inspired by the special recognition mechanisms and components of viruses, improvements in the design of carriers relating to targeting/penetration properties, as well as chemical component evolution, are also addressed.

Cationic polymer-derived carbon dots for enhanced gene delivery and cell imaging.

Carbon dots have attracted rapidly growing interest in recent years. In this report, we prepared two cationic polymer-derived carbon dots (Taea-CD and Cyclen-CD, collectively called C-dots) via a hydrothermal method. Transmission electron microscopy (TEM) results show that the C-dots were sphere-like and the size distribution was 1.8 ± 0.4 nm for Taea-CD and 5.4 ± 2 nm for Cyclen-CD. The C-dots emitted bright blue fluorescence under UV light (365 nm). Confocal laser scanning microscopy (CLSM) assay indicates that the C-dots-mediated transfection process could be detected in real time, and their tunable fluorescence emission under different wavelengths could satisfy varying requirements. Luciferase assay indicates that the transformation from the polymer to CD is an effective strategy to improve the transfection efficiency (TE) of the materials. Moreover, the C-dots also exhibit higher serum tolerance and cell viability than commercially available polyethyleneimine (PEI). These results demonstrate that the preparation of carbon dots from polymers is a promising method for developing multifunctional gene vectors with high TE and biocompatibility.

Photoluminescent F-doped carbon dots prepared by ring-opening reaction for gene delivery and cell imaging.

Carbon dots (CDs) are photoluminescent nanoparticles with distinctive properties, having great potential in nano-biomaterial systems such as gene/drug delivery vectors and cell imaging agents. Fluorine-doped CD C-6F was prepared by a one-step ring-opening polymerization-dehydrative carbonization (RPDC) approach based on low molecular weight polyethyleneimine (PEI, 600 Da) and fluorinated diglycidyl ethers, while the non-fluorinated counterpart C-6H and the CD prepared from PEI 600 Da solely (C-600) were also prepared for comparison. TEM, FT-IR and XPS were performed to determine the compositions and surface states of the CDs. In vitro cell experiment results reveal that the CDs prepared from RPDC approach have much higher transfection efficiency and cellular uptake than PEI 600 contrasts in various cell lines. Compared to non-fluorinated C-6H, C-6F exhibited distinctly higher transfection efficiency, and up to 30 and 260 times higher efficiency than PEI 25 kDa could be achieved in the absence and presence of serum, respectively, indicating the advantage of F-doping. Besides, these CDs exhibit good cell imaging capability under single wavelength excitation, making the materials suitable for cellular tracking and transfection mechanism studies. These results demonstrate that fluorine-doping is an efficient approach to obtained CD gene vectors with high efficiency and serum tolerance.

Amphiphilic carbon dots as versatile vectors for nucleic acid and drug delivery.

Carbon dot (CD)-based multifunctional delivery systems have shown great potential in both drug/gene delivery and bio-imaging. In this work, we present a strategy to simply construct amphiphilic CDs (ACDs) by conjugating hydrophobic alkyl epoxide to the surface amino groups of PEI 600-derived CDs. ACDs could well dissolve in water or organic solvents and emit bright fluorescence both in solutions and cells. 1HNMR also suggested that ACDs may form micelle-like structures in water, and their CMC could be determined. Enhanced green fluorescent protein (EGFP) expression and flow cytometry experiments showed that ACDs have higher transfection efficiency than Lipofectamine 2000 in A549 cells. Besides DNA, ACDs could also effectively transfect Sur siRNA toward A549 cells and cause early cell apoptosis. The 3D multicellular spheroids further confirmed their high potential for delivering therapeutic genes into the tumor tissue. On the other hand, ACDs also exhibited good drug loading ability. CLSM experiment results showed that DOX could be effectively internalized by the cell and slowly released from the drug/ACD complex. These results suggest that ACDs may not only serve as versatile delivery vectors with potential for applications in clinical cancer treatment, but also offer an inspiration for the discovery of CD-based gene/drug delivery systems.

Identification of odor signature chemicals in cocaine using solid-phase microextraction-gas chromatography and detector-dog response to isolated compounds spiked on U.S. paper currency.

Solid-phase microextraction (SPME) combined with gas chromatography (GC) is optimized and applied to the analysis of street-cocaine samples followed by the field-testing of isolated chemicals using certified detector dogs. SPME proves to be a very sensitive and rapid method for isolating odor chemicals from street-cocaine samples. SPME-GC and activated charcoal strip (ACS)-SPME-GC signature profile methods are developed for the detection and quantitation of cocaine-odor chemicals, including the optimization of controllable variables such as fiber chemistry, extraction time, and desorption time. The volatile odor chemicals in representative illicit cocaine samples are identified and quantitated by the ACS-SPME-GC signature profile method and direct injection. Field tests with drug detector dogs show methyl benzoate to be the dominant signature odor chemical along with cocaine on U.S. currency at a threshold level of approximately 1-10 microg when spiked or when 10 ng/s methyl benzoate is diffused from polymer bottles, which is required in order to initiate an alert. No other substance studied initiated consistent responses by the drug dogs. The results indicate that the microgram levels of cocaine that have been reported on circulated U.S. currency are insufficient to signal an alert from law-enforcement trained drug detector dogs.