DNAzyme-Powered Three-Dimensional DNA Walker Nanoprobe for Detection Amyloid β-Peptide Oligomer in Living Cells and in Vivo

Abstract

Amyloid β-peptide oligomer (AβO) is widely acknowledged as the promising biomarker for the diagnosis of Alzheimer's disease (AD). In this work, we designed a three-dimensional (3D) DNA walker nanoprobe for AβO detection and real-time imaging in living cells and in vivo. The presence of AβO triggered the DNAzyme walking strand to cleave the fluorophore (TAMRA)-labeled substrate strand modified on the gold nanoparticle (AuNP) surface and release TAMRA-labeled DNA fragment, resulting in the recovery of fluorescent signal. The entire process was autonomous and continuous, without external fuel strands or protease, and finally produced plenty of TAMRA fluorescence, achieving signal amplification effect. The nanoprobe enabled the quantitative detection of AβO in vitro, and the limit of detection was 22.3 pM. Given the good biocompatibility of 3D DNA walker nanoprobe, we extended this enzyme-free signal amplification method to real-time imaging of AβO. Under the microscope, nanoprobe accurately located and visualized the distribution of AβO in living cells. Moreover, in vivo imaging results showed that our nanoprobe could be used to effectively distinguish the AD mice from the wild-type mice. This nanoprobe with the advantages of great sensitivity, high specificity, and convenience, provides an outstanding prospect for AD's early diagnosis development.

Plasmonic Nanoparticles as Optical Sensing Probes for the Detection of Alzheimer’s Disease

“…More recently, Yin et al explored the potential of their 3D DNA walker nanoprobe (described in Section 4.2) for fluorescence imaging of AβOs in the APP/PS1 double transgenic (Tg) AD mouse model, compared with C57BL6 wild-type (WT) mice as controls. At all-time points from 30 to 360 min after injecting 2 nM of the nanoprobe, the fluorescence signal in the brain was higher in Tg mice, compared to WT mice ( Figure 9C), especially up to 240 min, and then rapidly decayed [92]. So, this nanosystem has great potential as a tool for AD diagnosis.…”

“…DNA molecular machines, in particular, DNA walkers, are considered attractive amplification strategies due to the advantage of the signal enhancement cascade generated by its autonomous movement [92]. Yin et al designed a 3D DNA walker nanoprobe for the sensitive detection and real-time in situ imaging of AβOs.…”

“…Yin et al designed a 3D DNA walker nanoprobe for the sensitive detection and real-time in situ imaging of AβOs. The DNA walker nanoprobe composed of AuNPs modified with aptamer-Zn 2+ -dependent DNAzyme walking strands and TAMRA-labeled hairpin substrate strands ( Figure 5C) enabled the in vitro fluorescence detection of AβOs in the concentration range of 0.1-1.0 nM, with a LOD of 22.3 pM, as shown in Figure 5C [92].…”

“…(C) In vivo fluorescence images and relative fluorescence signal of the WT (top row) and Tg (bottom row) mice at selected time points before and after injection of 3D DNA walker nanoprobe. Reprinted with permission from ref [92]…”

Rationally Programming Nanomaterials with DNA for Biomedical Applications

“…[214] www.advancedsciencenews.com www.advancedscience.com In addition to cancer therapy, the DNA-based nanostructures were also widely explored for the treatment of alleviating acute kidney injury, [170] wound healing, [215] Parkinson's disease, [216] and other diseases. [217][218][219][220]…”