Research For SPR Sensors Based On Graphene-gold Nanoparticles Hybrids

Graphene-gold nanoparticle hybrid materials possess numerous unique and advantageous physicochemical properties excellent catalytic activity, enhancements in mass transport, and a significantly higher effective surface area. As such, there has been significant effort invested in utilizing this material for the development of electrochemical sensors and optical sensors. In view that the surface plasmon resonance (SPR) biosensors based on graphene-gold nanoparticle hybrid materials have higher sensitivity, they have held the greatest promise for implementation into an enormous application range. Recently, the GO-AuNPs hybrids have been applied in the SPR biosensors for the detection of ractopamine and IgG. The GO-AuNPs hybrids were used as a solid support for the immobilization of recognition molecules in these previous works. However, few papers have reported on the utilization of GO-AuNPs hybrids, which played as signal tags, for the sensitive detection of miRNA. MiRNA is frequently dysregulated in various types of human cancers. It is urgently needed to detect miRNAs for early diagnosis and pathogenesis of cancers. In this paper, miRNA-141 was chose as a model target miRNA, and the following GO-AuNPs hybrids-based SPR biosensors were designed for the detection of miRNAs.1. A novel and simple SPR biosensor (GOAu-SPR) based on GO-AuNPs hybrids as signal tags was designed for the detection of miRNAs. Taking advantage of the GO-AuNPs hybrids and their enhanced performance in SPR biosensors, the detection of miRNA was carried out in only two steps. Firstly, the thiolated capture DNA probe with a short complete complementary sequence was immobilized on the Au film surface to recognize the part sequence of target miRNA. Subsequently, the assistant DNA-linked GO-AuNPs hybrids were employed to bind the other section of the target. It was found that the developed SPR biosensor was able to achieve a detection limit as low as 1 fM. Moreover, the method showed excellent ability to discriminate differences among miRNA-200 family members. Notably, human total RNA from cancer cells could also be detected, and the results were in excellent agreement with the ones obtained using qRT-PCR. On the basis of these findings, we believe that this method has great potential for quantitative detection of miRNA in complex samples.2. A highly sensitive SPR biosensor based on GO-AuNPs hybrids as signal tags was designed for the detection of miRNAs and adenosine. On the basis of the above work, the GO-AuNPs hybrids were applied in the SPR biosensor as an enhanced sensing platform for the direct immobilization of capture DNA, and the assistant DNA-linked GO-AuNPs hybrids were used as signal tags to further enhance the SPR signal. With this dual signal amplification, a detection limit of as low as 0.1 fM is achieved on the SPR biosensor. Moreover, this biosensor also showed high selectivity toward miRNA-200 family members, and demonstrated its applicability for the target detection in human total RNA from cancer cells. Applying the principle of specific binding of adenosine and split aptemer fragments, the sensor was also applied to the detection of adenosine, and it could detect as low as 0.1 pM adenosine. The sensor was proved to be of good commonality.