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Antibiotic resistance, the ability of some bacteria to resist antibiotic drugs, has been a major global health burden due to the extensive use of antibiotic agents. Antibiotic resistance is encoded via particular genes; hence the specific detection of these genes is necessary for diagnosis and treatment of antibiotic resistant cases. Conventional methods for monitoring antibiotic resistance genes require the sample to be transported to a central laboratory for tedious and sophisticated tests, which is grueling and time-consuming. We developed a paper-based chip, integrated with loop-mediated isothermal amplification (LAMP) and the “light switch” molecule [Ru(phen)2dppz]2+, to conduct turn-on fluorescent detection of antibiotic resistance genes. In this assay, the amplification reagents can be embedded into test spots of the chip in advance, thus simplifying the detection procedure. [Ru(phen)2dppz]2+was applied to intercalate into amplicons for product analysis, enabling this assay to be operated in a wash-free format. The paper-based detection device exhibited a limit of detection (LOD) as few as 100 copies for antibiotic resistance genes. Meanwhile, it could detect antibiotic resistance genes from various bacteria. Noticeably, the approach can be applied to other genes besides antibiotic resistance genes by simply changing the LAMP primers. Therefore, this paper-based chip has the potential for point-of-care (POC) applications to detect various gene samples, especially in resource-limited conditions.

Graphene oxide (GO) and quantum dots (QDs), as burgeoning types of nanomaterials, have gained tremendous interest in the biosensor field. In this work, we designed a novel multivariate testing strategy that depends on the fluorescence resonance energy transfer (FRET) effect between quantum dots (QDs) and graphene oxide (GO). It integrates the QD–GO FRET principle and QD probes with different emission peaks into a platform, aims at multiplex gene detection of a human infectious and highly pathogenic pathogen, Listeria monocytogenes(L. monocytogenes). With the development of a multiplex linear-after-the-exponential (LATE) polymerase chain reaction (PCR) system, the single-stranded DNA (ssDNA) products of hlyAgenes and iapgenes are obtained by simultaneous amplification of the target genes. Then with the hybridization of ssDNA products and QD probes, simultaneous homogeneous detection of two gene amplification products can be achieved by using GO as a fluorescence switch and monitoring the relevant emissions excited by a single light source. Distinguishable signals corresponding to target genes are obtained. With this developed approach, genomic DNA from L. monocytogenescan be detected as low as 100 fg/μL. Moreover, this platform has a good dynamic range from 102to 106fg/μL. It is indicated that this platform has potential to be a reliable complement for rapid gene detection technologies and is capable of reducing the false-negative and false-dismissal probabilities in routine tests.