Graphene and Aptamer-Based Biosensor for HPS70 Detection

Discharge of nuclear wastewater all over the world has heightened concerns about the health and edibility of marine aquatic products. Heat shock proteins (HSP), especially HSP70 plays a major role in the immune system of marine organisms when facing external stress. To understand the immune process and mechanism of marine organisms under nuclear pollution, realization the detection of HSP70 is necessary. The study involving the fabrication and testing of HSP70 biosensor based on graphene and nucleic acid aptamer, which taking advantage of graphene's high carrier mobility, exceptional electrical properties at room temperature and specific recognition of protein molecules of functionalized nucleic acid aptamers to realizing the detection. Such a biosensor was deposited on a polydimethylsiloxane (PDMS) convex array substrate to enhance device applicability and sensitivity. After that, morphology of the device, thickness, roughness and Raman spectra of the graphene were tested to prove the characterizing the functionalization modification process. Electrical behaviors of output curves under different HSP70 concentrations were tested to prove the validity of the sensor. The results showing that the surface functionalization of nucleic acid aptamers increasing the surface roughness of graphene and causing the doping effects, resulting in formation of defects in the material. Electrical performance tests revealed that under conditions of HSP70 concentration of 20 nmol and
$\boldsymbol{V}_{\boldsymbol{d}}=\mathbf{0.2}\ \boldsymbol{V}$
, the
$\boldsymbol{I}_{\boldsymbol{d}}$
of graphene decreased
$\mathbf{3.2}\ \boldsymbol{\mu} \boldsymbol{A}$
and further increased to
$\mathbf{6.6}\ \boldsymbol{\mu} \boldsymbol{A},\ \mathbf{9.7} \boldsymbol{\mu} \boldsymbol{A}$
, and
$\mathbf{12.8}\ \boldsymbol{\mu} \boldsymbol{A}$
for 40 nmol, 60 nmol, and 80 nmol, respectively. The results showed that a graphene and aptamer-based biosensor can be utilized to realizing Hsp70 with 20 nmol. This study theoretical and experimental foundation for the rapid and efficient detection of HSP70.