Based On A New Two-dimensional Nanomaterial-Ti₃C₂ MXenes, A Highly Sensitive Electrochemical Method For The Detection Of Exosomes Was Constructed

In these years,numerous researches have shown that exosomes play an important role in immune response,cell migration,cell differentiation,tumor invasion,etc.,and they can be used as biomarkers for early cancer diagnosis.As a result,the highly sensitive detection of exosomes is of great significance for clinical diagnosis,biomedical and biochemical research of cancer.The electrochemical method has the characteristics of high stability,high sensitivity,low background and easy operation,which makes it widely used in clinical diagnosis,environmental monitoring and biosensing.Therefore,the development of sensitive electrochemical methods for the detection of exosomes is of great significance.Ti₃C₂ MXenes,as an emerging two-dimensional nanomaterial,has high conductivity,large specific surface area and stronger reducing and catalytic ability,and it has been widely used in catalysis,capacitance,biological imaging or sensing.In view of the excellent properties of MXenes,we have used the strong catalytic performance and reduce ability to construct two kinds of multifunctional probes,and realize the highly sensitive electrochemical detection of exosomes.The main achievements are listed as following.Ti₃C₂ MXenes have been used as a bioprobe carrier for the construction of electrogenerated chemiluminescence?ECL?biosensor,enabling highly sensitive detection of exosomes secreted by breast cancer?MCF-7?cells.MXenes have high conductivity,large specific surface area and strong catalytic ability.Therefore,MXenes can not only load a large number of CD63 protein aptamers to specifically recognize MCF-7 exosomes,but also have the ability to catalyze the ECL emission of luminol.Therefor,we used CD63 protein aptamer-modified MXenes?MXenes-Apt2?as catalytic amplification of ECL nanoprobes to achieve stable and highly sensitive detection of MCF-7 exosomes.The linear range is from 5×10² particles/?L to 5×10⁶particles/?L,and the detection limit is 125 particles/?L.In addition,the ECL biosensor can also be applied for the detection of exosomes secreted by different cancer cells.The recovery for exosomes detection in serum were 95-104%,indicating that the ECL biosensor is promising in clinical exosome detection.ECL biosensor constructed by us can detect exosomes secreted by different cancer cells,and its signal amplification strategy can be used as a general means,which is also of important reference significance for the detection of other relevant disease markers.Prussian blue-MXenes-Apt?PB-MXenes-Apt?complexes were generated in situ by the reductivity of Ti₃C₂ MXenes and was used as an electrochemical probe for the highly sensitive electrochemical detection of the exosomes secreted by ovarian cancer?OVCAR?.Large specific surface area of MXenes was used to improve the coverage of CD63aptamer on the probe,and then the CD63 protein on OVCAR exosome surface was specifically identified.Meanwhile,the strong reduction of unsaturated Ti²⁺on the surface of MXenes was used to realize the in situ synthesis of PB-MXenes-Apt,PB-MXenes-Apt as an electrochemical probe has achieved the effect of enrichment amplification and reduction of background signals.The constructed electrochemical method realized the highly sensitive detection of OVCAR exosomes.The linear range was from 5×10²particles/?L to 5×10⁵ particles/?L,the detection limit is 230 particles/?L.In addition,the recoveryfor exosomes detected in serum is 97%-109%,indicating that the electrochemical biosensor based on the bioprobeis reliable,which is expected to be applied to the detection of exosomes in clinical samples.The electrochemical biosensor constructed by us can detect exosomes secreted by different cancer cells and the multiple signal amplification strategy is expected to be used for the early diagnosis of different cancers.