Biological microarrays with different proteins and different protein concentrations are detected without external labeling by an oblique-incidence reflectivity difference (OIRD) technique. The initial experiment results reveal that the intensities of OIRD signals can distinguish the different proteins and concentrations of protein. The OIRD technique promises feasible applications to life sciences for label-free and high-throughput detection.
WEN Juan1,LU Heng1,WANG Xu1,YUAN Kun1,L HuiBin1,ZHOU YueLiang1,JIN KuiJuan1,YANG GuoZhen1,LI Wei2 & RUAN KangCheng2 1 Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China
We successfully conduct the label-free and real-time detection of the interactions between epoxy groups and rabbit IgG and 5＇ CTT CAG GTC ATG AGC CTG AT 3＇ oligonucleotide, and between the hybridization of 5＇ CTT CAG GTC ATG AGC CTG AT 3＇ and its complementary 3＇ GAA GTC CAC TAC TCG GAC TA 5＇ oligonucleotide, by the oblique-incidence reflectivity difference （OI-RD） method. The dynamic curves of OI-RD signals, corresponding to the kinetic processes of biomolecular combination or hybridization, are acquired. In our case, the combination of epoxy groups with rabbit IgG and 5＇ CTT CAC CTC ATG AGC CTG AT 3＇ oligonucleotide need almost one and a half hours and about two hundred seconds, respectively; and the hybridization of the two oligonucleotides needs about five hundred seconds. The experimental results show that the OI-RD is a promising method for the real-time and label-free detection of biomolecular interactions.
Mouse-Immunoglobulin G(mouse-IgG) with different concentrations in a range from 1000 to 0.0128 μg/mL and a specific hybridization with goat anti-mouse IgG were detected successfully by using an oblique-incidence reflectivity difference(OI-RD) method.Two detection signals,consisting of an imaginary part(Im{Δp-Δs}) and a real part(Re{Δp-Δs}) of OI-RD,were obtained simultaneously.The detection results of hybridization by OI-RD were in accord with that of traditional fluorescent scans.In particular,we label-freely detected the washed mouse-IgG microarray with a series of concentrations and acquired a linear correlation between OI-RD intensities and the protein concentrations in logarithmic coordinates.The detection sensitivity of OI-RD can reach 14 fg.These experimental results suggest that the OI-RD method has potential applications in proteomics and clinical diagnosis.
We examine the repeatabilities of oblique-incidence reflectivity difference(OIRD) method for label-free detecting biological molecular interaction using protein microarrays.The experimental results show that the repeatabilities are the same in a given microarray or microarray-microarray and are consistent,indicating that OIRD is a promising label-free detection technique for biological microarrays.
DAI JunLI LinWANG JingYiHE LiPingLU HuaBinRUAN KangChengJIN KuiJuanYANG GuoZhen
In this work,we parallelly detected the specific binding between microarray targets including 12 different kinds of proteins and the probe solution containing five corresponding antibodies and quantitatively analyzed the interactions between CDH13 and solution phase anti-CDH13 at six different probe concentrations by oblique-incidence reflectivity difference(OIRD)method in label-free format.The detection sensitivity reached 10 ng/mL.The experimental results indicate that the OIRD method is a promising and competing technique not only in research work but also in clinic.
DAI JunLI LinHE LiPingRUAN KangChengLU HuiBinJIN KuiJuanYANG GuoZhen
The microarrays of 20-base oligonucleotide with different concentrations are detected before and after hybridization by the oblique-incidence reflectivity difference (OI-RD) method. The experimental results prove that OI-RD is a label-free method which can not only distinguish the concentration difference of oligonucleotides before and after the hybridization but also detect the hybridization of short oligonucleotides. At present the OI-RD method can detect 0.39 μmol/L 20-base oligonucleotide or less. These results suggest that the OI-RD method is a promising and potential technique for label-free detection of biological microarrays.
A high sensitivity photovoltaic effect has been observed in a heterojunction composed of n-type wide bandgap oxide SrTiO 3-δ and p-type Si fabricated by laser molecular beam epitaxy.The responsivity of open-circuit photovoltage can reach 10 4 V/W without any amplification under zero bias for the wavelength range from visible to near infrared light in nW-μW order.We attribute the high performance of the photovoltage responsivity to the interfacial photoelectric effects in the SrTiO 3-δ /Si heterojunction.From the experimental results,some ideas can be generalized to improve photovoltaic efficiency and develop high sensitivity photodetectors with wide bandgap oxide materials and Si.
WEN Juan 1,GUO HaiZhong 1,XING Jie 2,Lü HuiBin 1,JIN Kui-Juan 1,HE Meng 1 & YANG GuoZhen 1 1 Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China
