Exosome Isolation and Detection: From Microfluidic Chips to Nanoplasmonic Biosensor.

Exosomes are becoming more widely acknowledged as significant circulating indicators for the prognosis and diagnosis of cancer. Circulating exosomes are essential to the development and spread of cancer, according to a growing body of research. Using existing technology, characterizing exosomes is quite difficult. Therefore, a direct, sensitive, and targeted approach to exosome detection will aid in illness diagnosis and prognosis. The review discusses the new strategies for exosome isolation and detection technologies from microfluidic chips to nanoplasmonic biosensors, analyzing the advantages and limitations of these new technologies. This review serves researchers to better understand exosome isolation and detection methods and to help develop better exosome isolating and detecting devices for clinical applications.

Genetic support of the causal association between gut microbiome and COVID-19: a bidirectional Mendelian randomization study.

Background: The association between gut microbiome and coronavirus disease 2019 (COVID-19) has attracted much attention, but its causality remains unclear and requires more direct evidence. Methods: In this study, we conducted the bidirectional Mendelian randomization (MR) analysis to assess the causal association between gut microbiome and COVID-19 based on the summary statistics data of genome-wide association studies (GWASs). Over 1.8 million individuals with three COVID-19 phenotypes (severity, hospitalization and infection) were included. And 196 bacterial taxa from phylum to genus were analyzed. The inverse-variance weighted (IVW) analysis was chosen as the primary method. Besides, false discovery rate (FDR) correction of p-value was used. To test the robustness of the causal relationships with p-FDR < 0.05, sensitivity analyses including the secondary MR analyses, horizontal pleiotropy test, outliers test, and "leave-one-out" analysis were conducted. Results: In the forward MR, we found that 3, 8, and 10 bacterial taxa had suggestive effects on COVID-19 severity, hospitalization and infection, respectively. The genus Alloprevotella [odds ratio (OR) = 1.67; 95% confidence interval (95% CI), 1.32-2.11; p = 1.69×10-5, p-FDR = 2.01×10-3] was causally associated with a higher COVID-19 severity risk. In the reverse MR, COVID-19 severity, hospitalization and infection had suggestive effects on the abundance of 4, 8 and 10 bacterial taxa, respectively. COVID-19 hospitalization causally increased the abundance of the phylum Bacteroidetes (OR = 1.13; 95% CI, 1.04-1.22; p = 3.02×10-3; p-FDR = 2.72×10-2). However, secondary MR analyses indicated that the result of COVID-19 hospitalization on the phylum Bacteroidetes required careful consideration. Conclusion: Our study revealed the causal association between gut microbiome and COVID-19 and highlighted the role of "gut-lung axis" in the progression of COVID-19.

Prognostic value of extrahepatic metastasis on colon cancer with liver metastasis: a retrospective cohort study.

Introduction: The occurrence of metastasis is a threat to patients with colon cancer (CC), and the liver is the most common metastasis organ. However, the role of the extrahepatic organs in patients with liver metastasis (LM) has not been distinctly demonstrated. Therefore, this research aimed to explore the prognostic value of extrahepatic metastases (EHMs). Methods: In this retrospective study, a total of 13,662 colon patients with LM between 2010 and 2015 were selected from the Surveillance, Epidemiology, and End Results database (SEER). Fine and Gray's analysis and K-M survival analysis were utilized to explore the impacts of the number of sites of EHMs and different sites of EHMs on prognosis. Finally, a prognostic nomogram model based on the number of sites of EHMs was constructed, and a string of validation methods was conducted, including concordance index (C-index), receiver operating characteristic curves (ROC), and decision curve analysis (DCA). Results: Patients without EHMs had better prognoses in cancer-specific survival (CSS) and overall survival (OS) than patients with EHMs (p < 0.001). Varied EHM sites of patients had different characteristics of primary location site, grade, and histology. Cumulative incidence rates for CSS surpassed that for other causes in patients with 0, 1, 2, ≥ 3 EHMs, and the patients with more numbers of sites of EHMs revealed worse prognosis in CSS (p < 0.001). However, patients with different EHM sites had a minor difference in cumulative incidence rates for CSS (p = 0.106). Finally, a nomogram was constructed to predict the survival probability of patients with EHMs, which is based on the number of sites of EHMs and has been proven an excellent predictive ability. Conclusion: The number of sites of EHMs was a significant prognostic factor of CC patients with LM. However, the sites of EHMs showed limited impact on survival. Furthermore, a nomogram based on the number of sites of EHMs was constructed to predict the OS of patients with EHMs accurately.

Associations of Dietary Intakes with Gynecological Cancers: Findings from a Cross-Sectional Study.

Background: Gynecological cancers, including cervical cancer, ovarian cancer and endometrial cancer are leading causes of cancer-related death in women worldwide. Diet plays an important role in cancer development, which is widely accepted. However, the associations between dietary intakes and gynecological cancers remain unclear. Methods: A total of 12,437 women aged over 20 years from the National Health and Nutrition Examination Survey (NHANES), conducted from 2007−2016, were included in this study. The relationships between 30 dietary factors (4 macronutrients, 15 vitamins, 9 minerals, caffeine and alcohol) and gynecological cancers were assessed. Results: We observed negative correlations of intakes of phosphorus (odds ratio (OR), 95% confidence interval (CI); 0.998 (0.996, 0.999), p = 0.002) with cervical cancer, and intakes of vitamin B12 (0.812 (0.714, 0.925), p = 0.002), phosphorus (0.997 (0.996, 0.999), p < 0.001) and alcohol (0.971 (0.950, 0.992), p = 0.009) with endometrial cancer. The data showed positive associations of intake of caffeine (1.002 (1.001, 1.003), p = 0.003) with cervical cancer, and intake of copper (2.754 (1.313, 5.778), p = 0.009) with endometrial cancer. In addition, we found potential negative correlations between intake of vitamin B1 (p = 0.025) and cervical cancer; zinc (p = 0.048) and ovarian cancer; and potassium (p = 0.032) and endometrial cancer. Potential positive associations were found between intake of calcium and cervical cancer (p = 0.026) and endometrial cancer (p = 0.034), and between sodium (p = 0.042) and endometrial cancer. Intakes of protein, total sugars, total fat, cholesterol, vitamin A, alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, vitamin B2, niacin, vitamin B6, food folate, vitamin C, vitamin D, vitamin E, vitamin K, magnesium, iron and selenium showed no relationship with gynecological cancers (p > 0.05). Conclusions: Specific dietary factors were associated with gynecological cancers. More epidemiological studies are needed to validate our results.

Cancers and COVID-19 Risk: A Mendelian Randomization Study.

Observational studies have shown increased COVID-19 risk among cancer patients, but the causality has not been proven yet. Mendelian randomization analysis can use the genetic variants, independently of confounders, to obtain causal estimates which are considerably less confounded. We aimed to investigate the causal associations of cancers with COVID-19 outcomes using the MR analysis. The inverse-variance weighted (IVW) method was employed as the primary analysis. Sensitivity analyses and multivariable MR analyses were conducted. Notably, IVW analysis of univariable MR revealed that overall cancer and twelve site-specific cancers had no causal association with COVID-19 severity, hospitalization or susceptibility. The corresponding p-values for the casual associations were all statistically insignificant: overall cancer (p = 0.34; p = 0.42; p = 0.69), lung cancer (p = 0.60; p = 0.37; p = 0.96), breast cancer (p = 0.43; p = 0.74; p = 0.43), endometrial cancer (p = 0.79; p = 0.24; p = 0.83), prostate cancer (p = 0.54; p = 0.17; p = 0.58), thyroid cancer (p = 0.70; p = 0.80; p = 0.28), ovarian cancer (p = 0.62; p = 0.96; p = 0.93), melanoma (p = 0.79; p = 0.45; p = 0.82), small bowel cancer (p = 0.09; p = 0.08; p = 0.19), colorectal cancer (p = 0.85; p = 0.79; p = 0.30), oropharyngeal cancer (p = 0.31; not applicable, NA; p = 0.80), lymphoma (p = 0.51; NA; p = 0.37) and cervical cancer (p = 0.25; p = 0.32; p = 0.68). Sensitivity analyses and multivariable MR analyses yielded similar results. In conclusion, cancers might have no causal effect on increasing COVID-19 risk. Further large-scale population studies are needed to validate our findings.

Which Probiotic Is the Most Effective for Treating Acute Diarrhea in Children? A Bayesian Network Meta-Analysis of Randomized Controlled Trials.

Acute diarrhea is a major cause of morbidity and mortality in children under five. Probiotics are beneficial for treating acute diarrhea in children, but unclear which specific probiotic is the most effective. We performed a Bayesian network meta-analysis to examine the comparative effectiveness of probiotics. By searching EMBASE, PubMed, and the Cochrane Library up to 31 March 2021, randomized clinical trials (RCTs) on probiotics for treating acute diarrhea in children were included. Primary outcomes included the duration of diarrhea and diarrhea lasting ≥2 days, and secondary outcomes included the mean stool frequency on day 2 and duration of hospitalization, fever, and vomiting. We assessed the certainty of the evidence of outcomes according to Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guideline. Eighty-four studies with twenty-one different interventions in 13,443 children were included. For the primary outcomes, moderate evidence indicated that, Lactobacillus reuteri [mean difference (MD) = -0.84 day; 95% confidence interval (CI), -1.39, -0.29], Bifidobacterium lactis (MD = -0.98 day; 95%CI, -1.82, -0.14), Saccharomyces boulardii (MD = -1.25 day; 95%CI, -1.59, -0.91), Lactobacillus species (spp.) plus Bifidobacterium spp. plus Saccharomyces spp. (MD = -1.19 day; 95%CI, -1.81, -0.58), and Bacillus spp. plus Enterococcus spp. plus Clostridium spp. (MD = -1.1 day; 95%CI, -1.84, -0.35) significantly reduced the duration of diarrhea when compared with placebo. Saccharomyces boulardii [Odds ratio (OR) = 0.22; 95%CI, 0.11, 0.41] and Lactobacillus reuteri (OR = 0.23; 95%CI, 0.090, 0.60) significantly reduced the risk of diarrhea lasting ≥2 days when compared with placebo or no treatment, with moderate evidence. Among all probiotics, Saccharomyces boulardii may be the most effective in reducing both duration of diarrhea (compared with placebo) and risk of diarrhea lasting ≥2 days (compared with placebo or no treatment), with moderate evidence. To be conclusive, Saccharomyces boulardii may be the most effective probiotic for treating acute diarrhea in children, followed by several other single-strain and multi-strain probiotics.

The active fragments of ghrelin cross the blood-brain barrier and enter the brain to produce antinociceptive effects after systemic administration.

G (1-5)-NH2, G (1-7)-NH2, and G (1-9) are the active fragments of ghrelin. The aim of this study was to investigate the antinociceptive effects, their ability to cross the blood-brain barrier, and the receptor mechanism(s) of these fragments using the tail withdrawal test in male Kunming mice. The antinociceptive effects of these fragments (2, 6, 20, and 60 nmol/mouse) were tested at 5, 10, 20, 30, 40, 50, and 60 min after intravenous (i.v.) injection. These fragments induced dose- and time-related antinociceptive effects relative to saline. Using the near infrared fluorescence imaging experiments, our results showed that these fragments could cross the brain-blood barrier and enter the brain. The antinociceptive effects of these fragments were completely antagonized by naloxone (intracerebroventricular, i.c.v.); however, naloxone methiodide (intraperitoneal, i.p.), which is the peripheral restricted opioid receptor antagonist, did not antagonize these antinociceptive effects. Furthermore, the GHS-R1α antagonist [D-Lys3]-GHRP-6 (i.c.v.) completely antagonized these antinociceptive effects, too. These results suggested that these fragments induced antinociceptive effects through central opioid receptors and GHS-R1α. In conclusion, our studies indicated that these active fragments of ghrelin could cross the brain-blood barrier and enter the brain and induce antinociceptive effects through central opioid receptors and GHS-R1α after intravenous injection.

Wnt/ß­catenin signaling: Causes and treatment targets of drug resistance in colorectal cancer (Review).

Colorectal cancer (CRC) is the third most common malignant tumor in humans. Chemotherapy is used for the treatment of CRC. However, the effect of chemotherapy remains unsatisfactory due to drug resistance. Growing evidence has shown that the presence of highly metastatic tumor stem cells, regulation of non­coding RNAs and the tumor microenvironment contributes to drug resistance mechanisms in CRC. Wnt/ß­catenin signaling mediates the chemoresistance of CRC in these three aspects. Therefore, the present study analyzed the abundant evidence of the contribution of Wnt/ß­catenin signaling to the development of drug resistance in CRC and discussed its possible role in improving the chemosensitivity of CRC, which may provide guidelines for its clinical treatment.

Synthesis of Gold Nanoparticle Stabilized on Silicon Nanocrystal Containing Polymer Microspheres as Effective Surface-Enhanced Raman Scattering (SERS) Substrates.

Developing ideal surface-enhanced Raman scattering (SERS) substrates is significant in biological detection. Compared with free non-aggregated noble metal nanoparticles, loading metal nanoparticles on a large matrix can achieve a higher SERS effect due to the existence of many "hot spots". A novel SERS substrate with intense "hot spots" was prepared through reducing gold ions with silicon nanocrystal containing polymer microspheres. The substrate exhibits high SERS sensitivity with an enhancement factor of 5.4 × 107. By applying 4-mercaptopyridine as a Raman reporter, the developed SERS substrate can realize measurement of pH values. The intensity ratio of 1574 to 1607 cm-1 of 4-mercaptopyridine showed excellent pH sensitivity, which increased as the surrounding pH increased. With good stability and reliability, the pH sensor is promising in the design of biological detection devices.

A metal-organic zeolitic framework with immobilized urease for use in a tapered optical fiber urea biosensor.

A tapered single-mode coreless single-mode (SCS) structure with high sensitivity for sensing refractive index is described. In order to achieve high specificity of optical biosensors, here enzyme capsulation film was achieved by embedding urease in zeolitic imidazolate framework (ZIF-8/urease) through in situ growth approach on the coreless fibers. Determination of urea is achieved through online monitoring of its binding to the urease in zeolitic imidazolate framework. Refractive index change result in wavelength shifts of the optical fiber biosensor. The resonance wavelength exhibits a good linear relationship with urea concentration in the range of 1 to 10 mM with detection limit of 0.1 mM and sensitivity of 0.8 mM/RIU (refractive index unit) if operated with broadband light ranging from 1525 nm to 1590 nm. Final assessment of optical biosensor in real sample was performed where excellent performance in terms of sensitivity and selectivity was observed. Schematic representation of experimental setup and mechanism for urea detection. A tapered single-mode coreless single-mode (SCS) structure is placed between a broadband light source ranging (BBS) and optical spectrum analyzer (OSA). ZIF-8/urease composites are applied as a recognition layer for urea detection.

Octadecylamine degradation through catalytic activation of peroxymonosulfate by FeMn layered double hydroxide.

A kind of heterogeneous catalyst, FeMn layered double hydroxide (Fe-Mn-LDH), was fabricated by coprecipitation process and used as PMS activator to degrade a novel organic pollutant octadecylamine (ODA). And the X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microcopy (TEM), Mapping and X-ray photoelectron spectra (XPS) measurements were utilized to characterize the fresh and used Fe-Mn-LDH. After a serious of degradation experiments, it was clearly to see that the activator possessed excellent activation property for PMS and was capable of removing 85% ODA (10 mg·L-1) within 25 min obviously higher than pure PMS. Moreover, the effect of some elements (such as PMS consumption, catalyst consistence and initial pH value), different reaction system and catalyst repeatability on ODA degradation were also explored. And by identification of main radical experiment, SO4- and HO were both confirmed the primary radicals. What's more, extra anion and nature organic matter (NOM) addition experiment displayed that NOM, NO3- and CO32- perform a negative effect on ODA degradation but Cl- could promote it. In addition, repeated experiments and metal leaching after degradation showed good stability of Fe-Mn-LDH. Finally, based on the XPS and Gas Chromatography-Mass Spectrometer (GS-MS) technology, the possible degradation mechanism and pathway were proposed.

Microfluidic device for the analysis of MDR cancerous cell-derived exosomes' response to nanotherapy.

Exosomes are membrane-enclosed extracellular vesicles which have been indicated as important biomarkers of cancerous cell functionality, such as multiple drug resistance (MDR). Nanoparticles based chemotherapy is a promising strategy to overcome MDR by interfering the production and composition of exosomes. Therefore, tumor-derived exosomes post-treatment by nanotherapy are implied to play critical roles of biomarkers on cancer MDR analysis. However, the efficient isolation of such exosomes from extracellular environment for their therapeutic response analysis remains challenging. In this study, we presented a microfluidic device featured exosome specific anti-CD63 immobilized ciliated micropillars, which were capable to isolate cancer-derived exosomes from cell culture medium. The captured exosomes can be recovered intact by dissolving the cilia on the micropillars using PBS soaking. Owing to the immobilized antibody in the microfluidic device, nearly 70% of exosome from the biofluid could be isolated. So the secreted exosomes of the MDR and ordinary human breast cancer cells pre-treated by free drug or nanotherapy could be isolated with high purity. The drug contents of the isolated exosomes were measured to analysis of the exosomal pathway response of MDR cells to different chemotherapeutic formulations. Such analyses and further definition of the biomarkers of these exosomes could benefit the future investigations of accurately and reliably determine design principle, functional activity, and mechanisms of nanotherapy for MDR overcoming.

Enzyme-Embedded Metal-Organic Framework Colloidosomes via an Emulsion-Based Approach.

Improving the activity and stability of enzymes is significant in enzyme immobilization. Here a facile approach to prepare ring-like ZIF-8 colloidosomes and spherical catalase-embedded ZIF-8 colloidosomes is developed via one-step emulsion-based technique at the water/butanol interface. The influence of the concentrations of ZIF-8 nanocrystals and Pluronic F127 as well as the oil-water ratio was investigated. Compared with in situ biomineralization, the colloidosomes prepared via the pickering emulsion method show successful encapsulation of positively charged enzymes. By using catalase as an immobilized model, the immobilized catalase exhibits high biocatalytic activity, stability and recyclability compared with free catalase.

Silver-Nanoparticle-Embedded Porous Silicon Disks Enabled SERS Signal Amplification for Selective Glutathione Detection.

As the major redox couple and nonprotein thiol source in human tissues, the level of glutathione (GSH) has been a concern for its relation with many diseases. However, the similar physical and chemical properties of interference molecules such as cysteine (Cys) and homocysteine (Hcy) make discriminative detection of GSH in complex biological fluids challenging. Here we report a novel surface-enhanced Raman scattering (SERS) platform, based on silver-nanoparticle-embedded porous silicon disks (PSDs/Ag) substrates for highly sensitive and selective detection of GSH in biofluids. Silver nanoparticles (AgNPs) were reductively synthesized and aggregated directly into pores of PSDs, achieving a SERS enhancement factor (EF) up to 2.59 × 107. Ellman's reagent 5,5'-ditho-bis (2-nitrobenzoic acid) (DTNB) was selected as the Raman reactive reporting agent, and the GSH quantification was determined using enzymatic recycling method, and allowed the detection limit of GSH to be down to 74.9 nM using a portable Raman spectrometer. Moreover, the significantly overwhelmed enhancement ratio of GSH over other substances enables the discrimination of GSH detection in complex biofluids.

Multi-step encapsulation of chemotherapy and gene silencing agents in functionalized mesoporous silica nanoparticles.

Drug to carrier ratio is an important consideration in designing drug platforms, since a low loading capacity necessitates the use of high doses of carriers, which can result in side effects. Here, we have engineered a platform to co-deliver small molecule drugs and small interfering RNA (siRNA). This platform consists of cyclodextrin-grafted polyethylenimine (CP) functionalized mesoporous silica nanoparticles (MSNP). A unique multi-step encapsulation procedure was used to obtain a high loading capacity for doxorubicin (DOX) and siRNA oligos specific for the PKM2 gene that encodes pyruvate kinase M2, an enzyme catalyzing the final rate-limiting step in glycolysis. We systematically characterized this platform (CP-MSNP@DOX/PKM2) in vitro and evaluated its therapeutic efficacy in vivo with a mouse model of triple negative breast cancer (TNBC). Exposure of TNBC cells to CP-MSNP@DOX/PKM2 resulted in suppressed target gene expression, reduced cell proliferation, and enhanced apoptosis. Intravenous administration of the drug substantially decreased the tumor burden in comparison to DOX or siRNA monotherapy. In conclusion, we have developed a platform for efficient co-delivery of small molecule drugs and therapeutic siRNA.

Correction: In situ growth of fluorescent silicon nanocrystals in a monolithic microcapsule as a photostable, versatile platform.

Correction for 'In situ growth of fluorescent silicon nanocrystals in a monolithic microcapsule as a photostable, versatile platform' by Guixian Zhu, et al., Nanoscale, 2016, 8, 15645-15657.

In situ growth of fluorescent silicon nanocrystals in a monolithic microcapsule as a photostable, versatile platform.

A facile, one-step method was developed for the in situ formation of fluorescent silicon nanocrystals (SiNC) in a microspherical encapsulating matrix. The obtained SiNC encapsulated polymeric microcapsules (SiPM) possess uniform size (0.1-2.0 µm), strong fluorescence, and nanoporous structure. A unique two stage, time dependent reaction was developed, as the growth of SiNC was slower than the formation of polymeric microcapsules. The resulting SiPM with increasing reaction time exhibited two levels of stability, and correspondingly, the release of SiNC in aqueous media showed different behavior. With reaction time <1 h, the obtained low-density SiPM (LD-SiPM) as matrix microcapsules, would release encapsulated SiNC on demand. With >1 h reaction time, resulting high-density SiPM (HD-SiPM) became stable SiNC reservoirs. SiPM exhibit stable photoluminescence. The porous structure and fluorescence quenching effects make SiPM suitable for bioimaging, drug loading and sorption of heavy metals (Hg(2+) as shown) as an intrinsic indicator. SiPM were able to reduce metal ions, forming SiPM/metal oxide and SiPM/metal hybrids, and their applications in bio-sensing and catalysis were also demonstrated.

A versatile quantitation platform based on platinum nanoparticles incorporated volumetric bar-chart chip for highly sensitive assays.

Platinum nanoparticles incorporated volumetric bar-chart chip (PtNPs-V-Chip) is able to be used for point-of-care tests by providing quantitative and visualized readout without any assistance from instruments, data processing, or graphic plotting. To improve the sensitivity of PtNPs-V-Chip, hybridization chain reaction was employed in this quantitation platform for highly sensitive assays that can detect as low as 16 pM Ebola Virus DNA, 0.01ng/mL carcinoembryonic antigen (CEA), and the 10 HER2-expressing cancer cells. Based on this amplified strategy, a 100-fold decrease of detection limit was achieved for DNA by improving the number of platinum nanoparticle catalyst for the captured analyte. This quantitation platform can also distinguish single base mismatch of DNA hybridization and observe the concentration threshold of CEA. The new strategy lays the foundation for this quantitation platform to be applied in forensic analysis, biothreat detection, clinical diagnostics and drug screening.