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The estrogen receptor α positive (ERα+) subtype represents nearly 70% of all breast cancers (BCs), which seriously threaten women's health. Positron emission computed tomography (PET) characterizes its superiority in detecting the recurrence and metastasis of BC. In this article, an array of novel PET probes ([18F]R-1, [18F]R-2, [18F]R-3, and [18F]R-4) targeting ERα based on the tetrahydropyridinyl indole scaffold were developed. Among them, [18F]R-3 and [18F]R-4 showed good target specificity toward ERα and could distinguish MCF-7 (ERα+) and MDA-MB-231 (ERα-) tumors efficiently. Especially, [18F]R-3 could differentiate the ERα positive/negative tumors successfully with a higher tumor-to-muscle uptake ratio (T/M) than that of [18F]R-4. The radioactivity of [18F]R-3 in the MCF-7 tumor was 5.24 ± 0.84%ID/mL and its T/M ratio was 2.49 ± 0.62 at 25 min postinjection, which might be the optimal imaging time point in PET scanning. On the contrary, [18F]R-3 did not accumulate in the MDA-MB-231 tumor at all. The autoradiography analysis of [18F]R-3 on the MCF-7 tumor-bearing mice model was consistent with the PET imaging results. [18F]R-3 exhibited the pharmacokinetic property of rapid distribution and slow clearance, making it suitable for use as a diagnostic PET probe. Overall, [18F]R-3 was capable of serving as a PET radiotracer to delineate the ERα+ tumor and was worthy of further exploitation.
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Neoplasias de la Mama , Receptor alfa de Estrógeno , Radioisótopos de Flúor , Tomografía de Emisión de Positrones , Radiofármacos , Animales , Humanos , Femenino , Receptor alfa de Estrógeno/metabolismo , Radioisótopos de Flúor/farmacocinética , Ratones , Tomografía de Emisión de Positrones/métodos , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/metabolismo , Radiofármacos/farmacocinética , Células MCF-7 , Línea Celular Tumoral , Ratones Desnudos , Distribución Tisular , Ratones Endogámicos BALB C , Ensayos Antitumor por Modelo de Xenoinjerto , Diseño de FármacosRESUMEN
ß-galactosidase (ß-gal) has high activity in various malignancies, which is suitable for targeted positron emission tomography (PET) imaging. Meanwhile, ß-gal can successfully guide the formation of nanofibers, which enhances the intensity of imaging and extends the imaging time. Herein, we designed a ß-galactosidase-guided self-assembled PET imaging probe [68Ga]Nap-NOTA-1Gal. We envisage that ß-gal could recognize and cleave the target site, bringing about self-assembling to form nanofibers, thereby enhancing the PET imaging effect. The targeting specificity of [68Ga]Nap-NOTA-1Gal for detecting ß-gal activity was examined using the control probe [68Ga]Nap-NOTA-1. Micro-PET imaging showed that tumor regions of [68Ga]Nap-NOTA-1Gal were visible after injection. And the tumor uptake of [68Ga]Nap-NOTA-1Gal was higher than [68Ga]Nap-NOTA-1 at all-time points. Our results demonstrated that the [68Ga]Nap-NOTA-1Gal can be used for the purpose of a new promising PET probe for helping diagnose cancer with high levels of ß-gal activity.
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Sondas Moleculares , Nanofibras , Neoplasias , beta-Galactosidasa , Humanos , beta-Galactosidasa/análisis , Línea Celular Tumoral , Radioisótopos de Galio , Neoplasias/diagnóstico por imagen , Tomografía de Emisión de Positrones/métodosRESUMEN
Immune checkpoint inhibitors (ICIs) therapy based on programmed cell death ligand 1 (PD-L1) has shown significant development in treating several carcinomas, but not all patients respond to this therapy due to the heterogeneity of PD-L1 expression. The sensitive and accurate quantitative analysis of in vivo PD-L1 expression is critical for treatment decisions and monitoring therapy. In the present study, an aptamer-based dual-modality positron emission tomography/near-infrared fluorescence (PET/NIRF) imaging probe was developed, and its specificity and sensitivity to PD-L1 were assessed in vitro and in vivo. The probe precursor NOTA-Cy5-R1 was prepared by using automated solid-phase oligonucleotide synthesis. PET/NIRF dual-modality probe [68Ga]Ga-NOTA-Cy5-R1 was successfully synthesized and radiolabeled. The binding specificity of [68Ga]Ga-NOTA-Cy5-R1 to PD-L1 was evaluated by flow cytometry, fluorescence imaging, and cellular uptake in A375-hPD-L1 and A375 cells, and it showed good fluorescence properties and stability in vitro. In vivo PET/NIRF imaging studies illustrated that [68Ga]Ga-NOTA-Cy5-R1 can sensitively and specifically bind to PD-L1 positive tumors. Meanwhile, the rapid clearance of probes from nontarget tissues achieved a high signal-to-noise ratio. In addition, changes of PD-L1 expression in NCI-H1299 xenografts treated with cisplatin (CDDP) were sensitivity monitored by [68Ga]Ga-NOTA-Cy5-R1 PET imaging, and ex vivo autoradiography and western blot analyses correlated well with the change of PD-L1 expression in vivo. Overall, [68Ga]Ga-NOTA-Cy5-R1 showed notable potency as a dual-modality PET/NIRF imaging probe for visualizing tumors and monitoring the dynamic changes of PD-L1 expression, which can help to direct and promote the clinical practice of ICIs therapy.
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Antígeno B7-H1 , Neoplasias , Humanos , Antígeno B7-H1/metabolismo , Radioisótopos de Galio/química , Tomografía de Emisión de Positrones/métodos , Anticuerpos , Neoplasias/diagnóstico por imagen , Neoplasias/tratamiento farmacológico , Línea Celular TumoralRESUMEN
For the first time, a novel dithiomaleimides (DTM) based tetra-antennary GalNAc conjugate was developed, which enable both efficient siRNA delivery and good traceability, without incorporating extra fluorophores. This conjugate can be readily constructed by three click-type reactions, that is, amidations, thiol-dibromomaleimide addition and copper catalyzed azide-alkyne cycloaddition (CuAAC). And it also has comparable siRNA delivery efficiency, with a GalNAc L96 standard to mTTR target. Additionally, due to the internal DTMs, a highly fluorescent emission was observed, which benefited delivery tracking and reduced the cost and side effects of the extra addition of hydrophobic dye molecules. In all, the simple incorporation of DTMs to the GalNAc conjugate structure has potential in gene therapy and tracking applications.
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Química Clic , Colorantes Fluorescentes , ARN Interferente Pequeño/genética , Alquinos/química , Azidas/química , Cobre/química , Reacción de Cicloadición , CatálisisRESUMEN
In recent years, PD-1/PD-L1 checkpoint blockade immunotherapy with remarkable efficacy has set off a heat wave. The expression level of PD-L1, which plays a predictive role in anti-PD-1/PD-L1 therapy, could be quantified by noninvasive imaging with radiotracers. Herein, we introduced the synthesis and preliminary biological evaluation of a novel 99mTc-labeled small molecule radiotracer [99mTc]G3C-CBM for PD-L1 imaging. [99mTc]G3C-CBM was achieved with high radiochemical purity (>96 %) and remained good stability in PBS and FBS. In competitive combination experiment, [99mTc]G3C-CBM was displaced by increasing concentrations of unlabeled G3C-CBM, resulting in an IC50 value of 41.25±2.23 nM for G3C-CBM. The uptake of [99mTc]G3C-CBM in A375-hPD-L1 cells (17.51±2.08 %) was approximately 6.47 folds of that in A375 cells (2.71±0.36 %) after co-incubation for 2 h. The biodistribution results showed that the radioactivity uptake in A375-hPD-L1 tumor reached the maximum (0.35±0.01 %ID/g) at 2 h post injection, and the optimum tumor/muscle ratio of 2.94±0.29 occurred at the same time. In addition, [99mTc]G3C-CBM was quickly cleared from the blood with a clearance half-life of just 119.25 min. These results indicate that [99mTc]G3C-CBM is a potential SPECT PD-L1 imaging agent and is worthy of further study.
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Antígeno B7-H1 , Neoplasias , Humanos , Antígeno B7-H1/metabolismo , Distribución Tisular , Tomografía Computarizada de Emisión de Fotón Único/métodos , Transporte BiológicoRESUMEN
Two neuropilin 1 (NRP1)-targeted near-infrared fluorescence probes for tumor imaging were synthesized via click reaction. These two probes achieve excellent solubility and less aggregation. Importantly, they were able to rapidly target NRP1-overexpressing tumors and had long retention within tumors. Additionally, QS-1 with appropriate hydrophilicity displays higher tumor to muscle (T/M) ratio. And QS-1 can be easily modified with other functional group, and serve as a platform for constructing dual-modal or dual-targeting probes.
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Colorantes Fluorescentes , Neuropilina-1 , Línea Celular Tumoral , Imagen ÓpticaRESUMEN
INTRODUCTION: Fluoride is widely presented in drinking water and foods. A strong relation between fluoride exposure and obesity has been reported. However, the potential mechanisms on fluoride-induced obesity remain unexplored. Objectives and methods The effects of fluoride on the obesity were investigated using mice model. Furthermore, the role of gut homeostasis in exacerbation of the obesity induced by fluoride was evaluated. Results The results showed that fluoride alone did not induce obesity in normal diet (ND) fed mice, whereas, it could trigger exacerbation of obesity in high-fat diet (HFD) fed mice. Fluoride impaired intestinal barrier and activated Toll-like receptor 4 (TLR4) signaling to induce obesity, which was further verified in TLR4-/- mice. Furthermore, fluoride could deteriorate the gut microbiota in HFD mice. The fecal microbiota transplantation from fluoride-induced mice was sufficient to induce obesity, while the exacerbation of obesity by fluoride was blocked upon gut microbiota depletion. The fluoride-induced bloom of Erysipelatoclostridium ramosum was responsible for exacerbation of obesity. In addition, a potential strategy for prevention of fluoride-induced obesity was proposed by intervention with polysaccharides from Fuzhuan brick tea. Conclusion Overall, these results provide the first evidence of a comprehensive cross-talk mechanism between fluoride and obesity in HFD fed mice, which is mediated by gut microbiota and intestinal barrier. E. ramosum was identified as a crucial mediator of fluoride induced obesity, which could be explored as potential target for prevention and treatment of obesity with exciting translational value.
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Fluoruros , Receptor Toll-Like 4 , Animales , Ratones , Fluoruros/farmacología , Dieta Alta en Grasa/efectos adversos , Obesidad/prevención & controlRESUMEN
Fuzhuan brick tea (FBT) is a traditional popular beverage in the border regions of China. Nowadays, FBT has been attracted great attention due to its uniquely flavor and various health-promoting functions. An increasing number of efforts have been devoted to the studies on health benefits and chemistry of FBT over the last decades. However, FBT was still received much less attention than green tea, oolong tea and black tea. Therefore, it is necessary to review the current encouraging findings about processing, microorganisms, chemical constituents, health benefits and potential risk of FBT. The fungus fermentation is the key stage for processing of FBT, which is involved in a complex and unique microbial fermentation process. The fungal community in FBT is mainly dominated by "golden flower" fungi, which is identified as Aspergillus cristatus. A great diversity of novel compounds is formed and identified after a series of biochemical reactions during the fermentation process of FBT. FBT shows various biological activities, such as antioxidant, anti-inflammatory, anti-obesity, anti-bacterial, and anti-tumor activities. Furthermore, the potential risk of FBT was also discussed. It is expected that this review could be useful for stimulating further research of FBT.
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Camellia sinensis , Té , Té/química , Camellia sinensis/química , Hongos , Antioxidantes , China , FermentaciónRESUMEN
Dietary non-starch polysaccharides and phenolics are usually ingested at the same time. They are both regarded as prebiotics, and they regulate the intestinal microbiota through various mechanisms. Notably, however, reports of their combined or synergistic effects are rare. Arabinoxylan (AX), a polysaccharide, and chlorogenic acid (CA), a polyphenol, are widely consumed, and their effects on the microbiota have previously been discussed. In the present study, they were given to dextran sulfate sodium (DSS)-treated mice, separately and together, and the intestinal microbiota were investigated by high-throughput sequencing. The data showed that CA attenuated body weight loss, colon shortening, and histological damage in DSS-treated mice, while neither AX nor the AX+CA combination exhibited any ameliorating potential. AX+CA had less of a modulating effect on intestinal microbiota profiles than did CA. AX+CA administration increased the relative abundance of Flavonifractor, Coprobacillus, and Clostridium_XlVa, and decreased the abundance of Robinsoniella and Lactobacillus. Compared to AX and CA, AX+CA contributed to a more complicated shift in the biological functions of the intestinal microbiotaAX seemed to weaken the beneficial effects of CA, at least in the present experimental model of DSS-induced colitis. The combined effects and mechanisms of dietary polysaccharides and phenolic compounds on the intestinal microbiota and on overall health still need to be further investigated.
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CONTEXT: Coreopsis tinctoria Nutt (Asteraceae), named snow chrysanthemum, is known to have a high level of polyphenols. However, the potential prebiotic effect on modulating intestinal microflora is still unclear. OBJECTIVE: The chemical composition, antioxidant properties of snow chrysanthemum polyphenols (SCPs) and their effects on human intestinal microbiota were investigated. MATERIALS AND METHODS: SCPs were extracted using ultrasonic-assisted extraction, and further determined using UPLC-QE Orbitrap/MS. Five assays were used to investigate the antioxidant activities of SCPs. Subsequently, the effects of SCPs on intestinal microbiota in vitro were determined by high throughput sequencing and bioinformatics analysis. RESULTS: Marein, isookanin and cymaroside were the major phenolic compounds, which accounted for 42.17%, 19.53% and 12.25%, respectively. Marein exhibited higher scavenging capacities in DPPH (EC50 = 8.84 µg/mL) and super anion radical assay (EC50 = 282.1 µg/mL) compared to cymaroside and isookanin. The antioxidant capacity of cymaroside was weakest among the three phenolic compounds due to the highest EC50 values, especially for superoxide anion radical assay, EC50 > 800 µg/mL. The result of in vitro fermentation showed that the three phenolic compounds increased the relative abundances of Escherichia/Shigella, Enterococcus, Klebsiella, etc., and isookanin notably increased the relative abundance of Bifidobacterium and Lactobacillus. DISCUSSION AND CONCLUSIONS: SCPs exhibited antioxidant properties and potential prebiotic effects on modulating the gut microbiota composition. The findings indicated that SCPs consumption could exert prebiotic activity that is beneficial for human health.
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Chrysanthemum , Coreopsis , Microbioma Gastrointestinal , Antioxidantes/química , Chrysanthemum/química , Coreopsis/química , Humanos , Fenoles/análisis , Extractos Vegetales/química , Extractos Vegetales/farmacología , Polifenoles/análisis , Polifenoles/farmacologíaRESUMEN
Background: Phospholipase A2 receptor (PLA2R), located at the membrane of glomerular podocyte, is the major autoantigen of idiopathic membranous nephropathy (IMN), and its antibodies with a predominant IgG4 subclass lead to pathological lesions. Further studies could be performed to validate the clinical values of PLA2R-IgG, PLA2R-IgG4, and PLA2R-IgG4-to-IgG ratios, as ultrasensitive and quantitative immunoassays for PLA2R antibodies have been well established in our previous work. Methods: A cohort of 58 IMN patients, 30 of whom were followed from 3 to 42 months, was assessed for serum PLA2R-IgG and -IgG4 levels, and the ratio of PLA2R-IgG4/-IgG combined with relative clinicopathological indicators. Results: Serum PLA2R-IgG4 level was significantly correlated with glomerular PLA2R staining. In addition, it was strongly correlated with PLA2R-IgG and its ratio. PLA2R-IgG and -IgG4 levels were both correlated with high-density lipoprotein and erythrocyte sedimentation rates. The ratio at the first diagnosis can predict the remission, and its efficacy overmatched PLA2R-IgG4. In the survival curves, negative results for the ratio or PLA2R-IgG4 at the first diagnosis demonstrated higher remission rates. Conclusion: Serum PLA2R-IgG4 concentration may replace renal PLA2R immunohistochemistry in IMN diagnosis. We propose that the PLA2R-IgG4-to-IgG ratio and PLA2R-IgG4 could be novel indicators for remission prediction in clinical practice.
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Glomerulonefritis Membranosa , Glomerulonefritis Membranosa/patología , Humanos , Inmunoensayo , Inmunoglobulina G , Glomérulos Renales/patología , Receptores de Fosfolipasa A2RESUMEN
The purified fraction 3 of polysaccharides from Fuzhuan brick tea (FBTPS-3) could attenuate the colitis and modulate the gut microbiota. However, the relationship between anti-inflammatory effect of FBTPS-3 and the gut microbiota is still unknown. Thus, the anaerobic fermentation in vitro was used to investigate the potential mechanism. FBTPS-3 could be utilized and degraded by gut microbiota from inflammatory bowel disease (IBD) subjects. Furthermore, FBTPS-3 could modulate the composition and structure of IBD gut microbiota toward to that of healthy group. FBTPS-3 showed a superior modulated effect on IBD gut microbiota by increasing Bacteroides and decreasing Escherichia/Shigella. Furthermore, the fermentation solution rather than FBTPS-3 itself showed anti-inflammatory effects on lipopolysaccharide-treated RAW264.7 macrophages, which might be due to the metabolites such as short-chain fatty acids (SCFAs). Thus, FBTPS-3 can be expected as novel prebiotics for treatment of IBD via modulating gut microbiota, and promoting the production of SCFAs.
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Colitis , Microbioma Gastrointestinal , Enfermedades Inflamatorias del Intestino , Antiinflamatorios/farmacología , Colitis/inducido químicamente , Colitis/tratamiento farmacológico , Ácidos Grasos Volátiles/metabolismo , Fermentación , Humanos , Enfermedades Inflamatorias del Intestino/tratamiento farmacológico , Polisacáridos/química , Polisacáridos/farmacología , Té/químicaRESUMEN
Biosensors based on nucleic acid-structured electrochemiluminescence are rapidly developing for medical diagnostics. Here, we build an automated DNA molecular machine on Ti3C2/polyethyleneimine-Ru(dcbpy)3 2+@Au composite, which alters the situation that a DNA molecular machine requires laying down motion tracks. We use this DNA molecular machine to transduce the target concentration information to enhance the electrochemiluminescence signal based on DNA hybridization calculations. Complex bioanalytical processes are centralized in a single nucleic acid probe unit, thus eliminating the tedious steps of laying down motion tracks required by the traditional molecular machine. We found a detection limit of 0.68 pM and a range of 1 pM to 1 nM for the analysis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) specific DNA target. Recoveries range between 96.4 and 104.8% for the analysis of SARS-CoV-2 in human saliva. Supplementary Information: The online version contains supplementary material available at 10.1007/s10311-022-01434-9.
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Background: There are limited sensitive evaluation methods to distinguish people's symptoms of peripheral fatigue and central fatigue simultaneously. The purpose of this study is to identify and evaluate them after acute exercise with a simple and practical scale. Methods: The initial scale was built through a literature review, experts and athlete population survey, and a small sample pre-survey. Randomly selected 1,506 students were evaluated with the initial scale after exercise. Subjective fatigue self-assessments (SFSA) were completed at the same time. Results: The Acute Exercise-Induced Fatigue Scale (AEIFS) was determined after performing a factor analysis. In the exploratory factor analysis, the cumulative variance contribution rate was 65.464%. The factor loadings of the total 8 questions were 0.661-0.816. In the confirmatory factor analysis, χ2/df = 2.529, GFI = 0.985, AGFI = 0.967, NFI = 0.982, IFI = 0.989, CFI = 0.989, and RMSEA = 0.048. The Cronbach's alpha coefficient for the scale was 0.872, and it was 0.833 for peripheral fatigue and 0.818 for central fatigue. The intra-class correlation coefficient for the scale was 0.536, and the intra-class correlation coefficients for peripheral fatigue and central fatigue were 0.421 and 0.548, respectively. The correlation coefficient between the total score of the AEIFS and the SFSA score was 0.592 (p < 0.01). Conclusion: Our results demonstrate that the AEIFS can distinguish peripheral fatigue and central fatigue and can also reflect their correlation. This scale can be a useful evaluation tool not only for measuring fatigue after acute exercise but also for guiding reasonable exercise, choosing objective testing indicators, and preventing sports injuries resulting from acute exercise-induced fatigue.
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This study examined the effectiveness of Tai-Chi and running exercises on cardiorespiratory fitness and biomarkers in sedentary middle-aged adults under 24 weeks of supervised training. Methods Thirty-six healthy middle-aged adults (55.6 ± 5.3 yr) were randomly assigned into Tai-Chi, running and control groups. During a 24-week training period, the Tai-Chi and running groups were asked to perform exercises for 60 min/day and 5 days/week, which were supervised by Tai-Chi and running instructors throughout. Resting heart rate, lean mass, blood pressure and blood lipids were measured, and cardiorespiratory fitness (VO2max, Vmax and Peak heart rate) was assessed at the baseline and the 12- and 24-week interventions. Results Compared to the no-exercise control group, both the Tai-Chi and running groups significantly decreased resting heart rate, diastolic blood pressure and cardiorespiratory fitness and increased lean mass across the training session (p < 0.05). Compared to the Tai-Chi group, the running group showed greater improvement in VO2max and Vmax (p < 0.05) and reduced triglyceride and low-density lipoprotein cholesterol (p < 0.05). Conclusion Both Tai-Chi and running exercise showed beneficial effects on cardiorespiratory fitness and enhanced health-related outcomes in middle-aged adults. Although Tai-Chi exercises were less effective in VO2max than running, Tai-Chi may be considered as a plausible alternative to running exercises that can be achieved in the indoor-based setting.
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In this work, we designed an ECL ratiometric biosensor with a three-stranded Y-type DNA (Y-DNA) probe and induced a hybridization chain reaction (HCR) for the highly sensitive detection of SARS-CoV-2 nucleic acid. The important component of this system is the self-assembled Y-Shaped probe based on three nucleic acids. Y1, Y2, and Y3 can be linked by complementary base pairing to Hairpin1 (H1), Hairpin2 (H2), and Ru modified DNA (Ru1), respectively. H1 and H2 can trigger the HCR reaction when activated by the SARS-CoV-2 RdRp gene and the 5' end of Ru1. The 5' end of Ru1 is modified with the Ru complex, which can produce a strong electrochemiluminescence luminescence signal at 620 nm under an applied voltage. Through the amplification of Y-DNA-induced HCR reaction, Ru1 on the electrode surface gradually increased, the ECL signal at 460 nm was gradually quenched, and the signal at 620 nm was steadily generated. The SARS-CoV-2 RdRp gene can be quantified according to the degree of decrease of ECL signal at 460 nm and the increase of ECL signal at 620 nm. Combining the two signal amplification strategies, this ratiometric ECL biosensor can accurately and efficiently detect the target gene with a detection limit of 59 aM.
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Técnicas Biosensibles , COVID-19 , Técnicas Electroquímicas , Humanos , Mediciones Luminiscentes , Hibridación de Ácido Nucleico , ARN Polimerasa Dependiente del ARN , SARS-CoV-2RESUMEN
Under the condition of normalized epidemic, how athletes train and compete well has been in the spotlight. This article reported the symptom, hospitalization and training situation of seven confirmed cases of coronavirus-disease-2019 (COVID-19) among Chinese national teams. Moreover, the paper summarized the experience of Chinese national teams in terms of epidemic prevention and control, treatment of infection, and safe return to play. Through a scientific combination of medication and non-medical treatment, seven athletes were all discharged from the hospital. These discharged athletes underwent strict isolation and scientific training before returning to sports teams. Before returning to play, continuous monitoring of physical and mental condition was required. All seven athletes returned to play safely and performed excellently. As for hosting large-scale sporting events, the entire enclosed-loop management from immigration to competition was proposed in this paper. This study could serve as a standard of epidemic prevention and control, treatment for infection and safe return to play during competition and training around the world.
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In this work, we constructed an exonuclease III cleavage reaction-based isothermal amplification of nucleic acids with CRISPR/Cas12a-mediated pH-induced regenerative Electrochemiluminescence (ECL) biosensor for ultrasensitive and specific detection of SARS-CoV-2 nucleic acids for SARS-CoV-2 diagnosis. The triple-stranded nucleic acid in this biosensor has an extreme dependence on pH, which makes our constructed biosensor reproducible. This is essential for effective large-scale screening of SARS-CoV-2 in areas where resources are currently relatively scarce. Using this pH-induced regenerative biosensor, we detected the SARS-CoV-2 RdRp gene with a detection limit of 43.70 aM. In addition, the detection system has good stability and reproducibility, and we expect that this method may provide a potential platform for the diagnosis of COVID-19.
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Despite advances in immunotherapy for the treatment of cancers, not all patients can benefit from programmed cell death ligand 1 (PD-L1) immune checkpoint blockade therapy. Anti-PD-L1 therapeutic effects reportedly correlate with the PD-L1 expression level; hence, accurate detection of PD-L1 expression can guide immunotherapy to achieve better therapeutic effects. Therefore, based on the high affinity antibody Nb109, a new site-specifically radiolabeled tracer, 68Ga-NODA-cysteine, aspartic acid, and valine (CDV)-Nb109, was designed and synthesized to accurately monitor PD-L1 expression. The tracer 68Ga-NODA-CDV-Nb109 was obtained using a site-specific conjugation strategy with a radiochemical yield of about 95% and radiochemical purity of 97%. It showed high affinity for PD-L1 with a dissociation constant of 12.34 ± 1.65 nM. Both the cell uptake assay and positron emission tomography (PET) imaging revealed higher tracer uptake in PD-L1-positive A375-hPD-L1 and U87 tumor cells than in PD-L1-negative A375 tumor cells. Meanwhile, dynamic PET imaging of a NCI-H1299 xenograft indicated that doxorubicin could upregulate PD-L1 expression, allowing timely interventional immunotherapy. In conclusion, this tracer could sensitively and dynamically monitor changes in PD-L1 expression levels in different cancers and help screen patients who can benefit from anti-PD-L1 immunotherapy.
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Early diagnosis and timely management of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) are the keys to preventing the spread of the epidemic and controlling new infection clues. Therefore, strengthening the surveillance of the epidemic and timely screening and confirming SARS-CoV-2 infection is the primary task. In this work, we first proposed the idea of activating CRISPR-Cas12a activity using double-stranded DNA amplified by a three-dimensional (3D) DNA walker. We applied it to the design of an electrochemiluminescent (ECL) biosensor to detect the SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) gene. We first activated the cleavage activity of CRISPR-Cas12a by amplifying the target DNA into a segment of double-stranded DNA through the amplification effect of a 3D DNA walker. At the same time, we designed an MXene based ECL material: PEI-Ru@Ti3C2@AuNPs, and constructed an ECL biosensor to detect the RdRp gene based on this ECL material as a framework. Activated CRISPR-Cas12a cleaves the single-stranded DNA on the surface of this sensor and causes the ferrocene modified at one end of the DNA to move away from the electrode surface, increasing the ECL signal. The extent of the change in electrochemiluminescence reflects the concentration of the gene to be measured. Using this system, we detected the SARS-CoV-2 RdRp gene with a detection limit of 12.8 aM. This strategy contributes to the rapid and convenient detection of SARS-CoV-2-associated nucleic acids and promotes the clinical application of ECL biosensors based on CRISPR-Cas12a and novel composite materials.