Ratiometric fluorescence probe for accurate detection of Concanavalin A by coupling fluorescent microsphere with boric acid functionalized carbon dots

Accurate and sensitive strategies for Concanavalin A(Con A)sensing are conducive to the better cognition of various important biological and physiological processes.Here,by designing dextran-functionalized fluorescent microspheres(DxFMs)and boric acid-modified carbon dots(BCDs)as recognition unit and built-in signal reference respectively,a ratiometric fluorescent detection platform was proposed for Con A detection with high reliability.In this protocol,the BCDs/DxFMs precipitation was formed due to the covalent interactions between cis-diol of DxFMs and boronic acid groups of BCDs,thus only fluorescence of BCDs could be detected in the supernatant.When Con A was presented,it could bind to DxFMs through its carbohydrate recognition ability and suppress the subsequent assembly between DxFMs and BCDs,leading to the simultaneous capture of DxFMs and BCDs fluorescence in the supernatant.Since the BCDs content was superfluous,their fluorescence intensities were basically constant in all cases.Based on the unchanged BCDs fluorescence signal and target-dependent DxFMs fluorescence signal in supernatant,the ratiometric detection of Con A was realized.Under optimized conditions,this ratiometric fluorescent platform displayed a linear detection range from 0.125μg/mL to 12.5μg/mL with a detection limit of 0.089μg/mL.Moreover,satisfied analytical outcomes for Con A detection in serum samples were obtained,manifesting huge application potential of this ratiometric fluorescent platform in clinical diagnosis.

Dual-miRNA-Propelled Three-Dimensional DNA Walker for Highly Specific and Rapid Discrimination of Breast Cancer Cell Subtypes in Clinical Tissue Samples

Accurate discrimination of cell subtypes at the molecular level is especially important for cancer diagnosis,but no current method allows rapid and precise detection of breast cancer subtypes.Herein,we developed an elegant DNA walker for direct and rapid differentiation of breast cancer cell subtypes via detection of dual-miRNAs in clinical tissue samples.This DNA nanomachine can be specifically initiated by endogenous miR-21 and miR-31,and the sensitivity was dramatically improved due to the DNAzyme-mediated signal amplification.This DNA walker enabled rapid detection of double miRNA characteristics in different breast cell lines and also distinguished the fluctuations in a single cell.Applications of this DNAzyme-based nanomachine in vivo and in clinical samples were demonstrated for efficient detection of breast cancer subtypes,making the method generally applicable for precise management of cancers.

Two-Dimension(2D) Cu-MOFs/aptamer Nanoprobe for In Situ ATP Imaging in Living Cells

Monitoring the intracellular adenosine triphosphate(ATP)level is vital for elaborating its function in physiological states.However,the intracellular fluorescence sensing of ATP using ATP aptamer remains difficult owing to non-target displacement and susceptibility toward enzymatic degradation.Herein,by combining 2D Cu-MOF nanosheets and FAM labelled ATP aptamer,we developed a fluorescent Cu-MOFs/aptamer nanoprobe to image and sense intracellular ATP.This nanoprobe reveals a very low fluorescence intensity because of the excellent quenching efficiency of 2D Cu-MOF nanosheets.The presence of ATP was capable to dissociate the FAM-aptamer from Cu-MOF nanosheets and resulted in an intense fluorescence signal.The Cu-MOFs/aptamer nanoprobe enables highly sensitive and selective measurement of ATP level ranging from 10μM to 800μM with a detection limit of 4.24μM.This nanosystem also further realized in situ detection of the undulation of ATP trigged by drug stimulation,depending on the selective delivery of the nanoprobe and attractive capability of resisting nonspecific displacement.The constructed nanoprobe may supply a potential platform in clinical diagnostics and biological studies.

Extracellular Milieu and Membrane Receptor Dual-Driven DNA Nanorobot for Accurate in Vivo Tumor Imaging

Precise diagnostic approaches have great potential in cancer intervention and prognosis.Although diverse DNA nanoprobes have been reported for tumor diagnosis,precise tumor imaging in vivo still encounters a great challenge due to the scarcity of exquisite design methodology.Herein,by assembling three programmable modules on a DNA triangular prism,we engineered a DNA nanorobot for simultaneous recognition of extracellular pH and cancer cell membrane receptor in an intelligent manner.Since the design uses two heterogeneous types of biomarkers as inputs,pH-RE not only could discriminate target tumor cells from similar cell mixtures with a recognition accuracy as high as 98.8%,but also could perform precise tumor imaging in living mice by intravenous injection.We expect that this extracellular pH and membrane receptor dual-driven DNA nanorobot will facilitate the establishment of a novel design paradigm for precise cancer diagnosis and therapy.

Molecular recognition triggered aptazyme cascade for ultrasensitive detection of exosomes in clinical serum samples

Exosomes have attracted widespread interest due to their inherent advantages in tumor diagnosis and treatment monitoring.However,it is still a big challenge for highly sensitive and specific detection of exosome in real complexed samples.Herein,a molecular recognition triggered aptazyme cascade strategy was developed for ultrasensitive detection of cancer exosomes in clinical serum samples.In this design,one target exosome could capture a large quantity of aptazymes for the first-step signal amplification.And then the captured aptazyme was activated and recycled to release the fluorophore-labelled substrate strand for a cascaded signal amplification.Notably,the activation of aptazyme only occurs whenithas bound with target exosome,ensuring a low background.The experimental results show that the limit of detection(LOD)and the limit of quantification(LOQ)are 3.5×10^(3) particles/μL and 1.7×10^(4) particles/μL,respectively,which is comparable to the results of most existed fluorescence-based exosome probes.Moreover,this assay possesses high specificity to distinguish exosomes derived from other cell lines.Furthermore,this fluorescence probe was utilized in cancer patient and healthy serum samples successfully,suggesting its great potential for clinical diagnosis and biological studies.