Two-layer Three-dimensional DNA Walker With Highly Integrated Entropy-driven And Enzyme-powered Reactions For HIV Detection

Background Acquired immunodeficiency syndrome(AIDS)is a common infectious disease caused by the human immune deficiency virus(HIV),which can lead to the destruction of the whole immune system,so the detection of HIV is desirable and important for its diagnosis.At present,the diagnosis of AIDS mainly depends on the detection of HIV antibodies,antigens,nucleic acids,CD4~+/CD8~+T cells and virus.However,the existing detection methods still have some deficiencies,such as enzyme-linked immunosorbent assay(ELISA)is unable to identify the“window period”of HIV infection due to the low level of HIV antibody which needs a long period for generating.Polymerase chain reaction(PCR),flow cytometry and virus culture methods are not only limited by the high requirements of laboratories and personnel,but also by expensive instruments.In order to identify HIV infected persons and AIDS patients as early as possible so as to provide immediate consultation and treatment,it is of great importance to develop a new methodology for HIV testing that can not only meet the actual needs of the current HIV testing work,but also reflect the development of testing technology.Objective In order to meet the actual needs of HIV testing,a new methodology for HIV testing is constructed by using two-layer three-dimensional DNA walking sensors.Methods The 3-D DNA walker sensor is constructed by assembling densely carboxyfluorescein-labeled single strand oligonucleotides(inner-layer tracks)and nucleic acid complex S(outer-layer tracks)on a microparticle.In the presence of the target,outer and inner tracks are activated in turn,thereby releasing a great deal of the signal reporters for signal reading.Results Our 3-D DNA walker sensor can realize the target detection in the range from 2 pM to 5 nM within one hour.Besides,the specific walker sensor can clearly distinguish even one-base mismatched target analogue.More importantly,our walker sensor can also test the target in human serum samples in the concentrations as low as 0.1 nM,which provides a bridge between real sample detection and clinical application.Conclusion We propose a new two-layer 3-D DNA walker sensor with highly integrated entropy-driven and enzyme-powered reactions for the first time.This smart strategy could also be generalized to any target of interest by proper design.