Artful union of a zirconium-porphyrin MOF/GO composite for fabricating an aptamer-based electrochemical sensor with superb detecting performance

More and more attentions have been focused on design and synthesis of novel metal-organic framework/graphene oxide(MOF/GO)composites with unique performance.Zirconium-porphyrin MOF(PCN-222)is in-situ synthesis with the existence of GO with-COOH group to artfully fabricate a PCN-222/GO composite.This composite can be employed as functional material to modify the working electrode.Thanks to excellent electrical conductivity of GO,abundant mesoporous channels and numerous Zr(Ⅳ)metal sites of PCN-222,this composite can immobilize a large amount of aptamer through strongπ-πstacking interaction and high affinity between phosphate group of aptamer and Zr(Ⅳ)site of PCN-222 simultaneously.Hence,an ultra-sensitive electrochemical aptasensor based on PCN-222/GO composite can quantificationally detect trace chloramphenicol with limit of detection of 7.04 pg/m L(21.79 pmol/L)from 0.01 ng/m L to 50 ng/m L by electrochemical impedance spectroscopy even in real samples.Meanwhile,this fabricated aptasensor reveals good repeatability,outstanding selectivity and preferable long-term storage.This research provides a useful approach to construct MOF/GO composites for fabricating electrochemical aptasensors in the electrochemical detection field.

An intriguing electrochemical impedance aptasensor based on a porous organic framework supported silver nanoparticles for ultrasensitively detecting theophylline

Porous organic frameworks(POFs)are excellently stable porous materials,which can be employed as host platforms to support metal nanoparticles as functional composites for various applications.Herein,a novel POF is successfully prepared via Friedel-Crafts reaction.Silver nanoparticles(AgNPs)are embedded in the prepared POF to generate an Ag@POF composite,which not only possesses high surface area,outstanding physicochemical stability and outstretchedπ-conjugation skeleton,but also exhibits preferable electrochemical stability and conductivity.This composite is able to immobilize a mass of aptamer strands to fabricate an intriguing electrochemical aptasensor.Electrochemical impedance spectroscopy(EIS)is a commonly used technology to analyze the electrochemical signal variation.The Ag@POF-based biosensor shows the excellent electrochemical detection behavior through analyzing EIS.For instance theophylline as a research mode,the Ag@POF based electrochemical aptasensor reveals ultra-sensitiveness,high selectivity,remarkable stability,good repeatability and simple operability even in various real samples.Notably,this aptasensor has the sensitive detection performance with the limit of detection of 0.191 pg/m L(1.06 pmol/L)in a wide concentration range of 5.0×10^(-4)–5.0 ng/m L(2.78×10^(-3)–27.8 nmol/L).

Prognostic analysis of prostaglandin D2 synthase in diffuse large B‑cell lymphoma

Purpose We aimed to analyse the correlation between prostaglandin D2 synthase(PTGDS)and a diffuse large B-cell lymphoma(DLBCL)prognosis.Methods We retrospectively collected two hundred paraffin-embedded tissue specimens that were pathologically diagnosed as DLBCL in the Fujian Tumour Hospital between January 2014 and December 2018.An abundance of paraffin-embedded tumour tissues were obtained.Twenty patients with lymphocyte-rich,benign,tissue-reactive,hypertrophic tonsillitis were selected as controls.Wax blocks were selected for primary cases and the controls were screened by professional pathologists.The levels of prostaglandin D2 synthase(PTGDS)and the EMT-related molecules,E-cadherin and vimentin,were detected by immunohistochemistry in clinical samples.A chi-square test revealed the correlations between PTGDS expression and clinicopathological characteristics,including age,sex,primary site,clinical stage,immunotyping,and International Prognostic Index(IPI)score.The Kaplan–Meier survival analysis was performed,and the diagnostic value was evaluated by receiver operating characteristic(ROC)curve analysis.Results A total of 138 cases(69%)were found to be PTGDS positive(>30%positive cells).PTGDS staining was negative(<30%positive cells)in 62 cases(31%).We collected the corresponding clinicopathological information and found that PTGDS expression was not significantly related to the patients’age,tumour stage,presence of extranodal invasion,or IPI score.According to the follow-up data,patients with low PTGDS expression had poor progression-free survival(PFS)and overall survival(OS),with 2-year PFS and OS rates of 41.7%and 50%,respectively.The 2-year PFS and OS rates of PTGDS-positive patients were 89.3%and 92.9%,respectively(P<0.0001),and the differences were significant.Conclusion We found that the expression level of PTGDS is significantly correlated with the prognosis of diffuse large B-cell lymphoma.