Ultrasensitive Detection of Ebola Virus Oligonucleotide Based on Upconversion Nanoprobe/Nanoporous Membrane System

Abstract

Ebola outbreaks are currently of great concern and therefore it is urgently needed to develop effective diagnosis methods. The key for lethal virus detection is high sensitivity, considering the early stage detection of virus may increase the probability of survival. Here we propose a luminescence scheme of assay consisted of BaGdF5:Yb/Er upconversion nanoparticles (UCNPs) conjugated with oligonucleotide probe and gold nanoparticles (AuNPs) linked with target Ebola virus oligonucleotide. As a proof of concept, a homogeneous assay was fabricated and tested, yielding a detection limit at pM level. The luminescence resonance energy transfer is ascribed to the spectral overlapping of upconversion luminescence (UCL) and the absorption characteristics of AuNPs. Moreover, we anchored the UCNPs and AuNPs on a nanoporous alumina (NAAO) membrane to form a heterogeneous assay. Importantly, the detection limit was greatly improved, exhibiting a remarkable value at fM level. The enhancement is attributed to the increased light-matter interaction throughout the nanopore walls of NAAO membrane. The specificity test suggested that the nanoprobes were specific to Ebola virus oligonucleotides. The strategy combining UCNPs, AuNPs and NAAO membrane provides a new insight to low-cost, rapid and ultrasensitive detection of different diseases. Furthermore, we present the feasibility study to evaluate clinical detection using inactivated Ebola virus samples. The detection results show the potential of our heterogeneous design for practical application.