Real-time wash-free detection of unlabeled PNA-DNA hybridization using discrete FET sensor.

We demonstrate an electrochemical sensor for detection of unlabeled single-stranded DNA using peptide nucleic acid (PNA) probes coupled to the field-effect transistor (FET) gate. The label-free detection relies on the intrinsic charge of the DNA backbone. Similar detection schemes have mainly concentrated on sensitivity improvement with an emphasis on new sensor structures.

Integrated Acoustic Separation, Enrichment, and Microchip Polymerase Chain Reaction Detection of Bacteria from Blood for Rapid Sepsis Diagnostics.

This paper describes an integrated microsystem for rapid separation, enrichment, and detection of bacteria from blood, addressing the unmet clinical need for rapid sepsis diagnostics. The blood sample is first processed in an acoustophoresis chip, where red blood cells are focused to the center of the channel by an acoustic standing wave and sequentially removed. The bacteria-containing plasma proceeds to a glass capillary with a localized acoustic standing wave field where the bacteria are trapped onto suspended polystyrene particles.

Closed-tube human leukocyte antigen DQA1∗05 genotyping assay based on switchable lanthanide luminescence probes.

Genotyping in closed tube is commonly performed using polymerase chain reaction (PCR) amplification and allele-specific oligonucleotide probes using fluorescence resonance energy transfer (FRET). Here we introduce a homogeneous human leukocyte antigen (HLA)-DQA1∗05 end-point PCR assay based on switchable lanthanide luminescence probe technology and a simple dried blood sample preparation. The switchable probe technology is based on two non-luminescent oligonucleotide probes: one carrying a non-luminescent lanthanide chelate and the other carrying a light-absorbing antenna ligand.

Lanthanide chelate complementation and hydrolysis enhanced luminescent chelate in real-time reverse transcription polymerase chain reaction assays for KLK3 transcripts.

The requirement for high-performance reporter probes in real-time detection of polymerase chain reaction (PCR) has led to the use of time-resolved fluorometry of lanthanide chelates. The aim of this study was to investigate the applicability of the principle of lanthanide chelate complementation (LCC) in comparison with a method based on hydrolysis enhancement and quenching of intact probes. A real-time reverse transcription (RT) PCR assay for kallikrein-related peptidase 3 (KLK3, model analyte) was developed by using the LCC detection method.

Homogeneous duplex polymerase chain reaction assay using switchable lanthanide fluorescence probes.

We have developed a duplex polymerase chain reaction (PCR) assay based on switchable lanthanide chelate complementation probes. In the complementation probe technology, two nonfluorescent oligonucleotide probes, one labeled with a lanthanide ion carrier chelate and another with a light absorbing antenna ligand, form a fluorescent complex by self-assembly of the reporter molecules when the two probes are hybridized in adjacent positions to the target DNA. Here we report the synthesis of a new terbium(III) (Tb(III)) ion carrier chelate and a new light-absorbing antenna ligand for Tb(III) and the development of a duplex Chlamydia trachomatis (Ct) PCR assay.

Homogenous M13 bacteriophage quantification assay using switchable lanthanide fluorescence probes.

We have developed a rapid and reliable bacteriophage quantification method based on measurement of phage single-stranded DNA (ssDNA) using switchable lanthanide chelate complementation probes. One oligonucleotide probe contains a non-fluorescent lanthanide ion carrier chelate and another probe is labeled with a light absorbing antenna ligand. Hybridization of the non-fluorescent complementation probes in adjacent positions on the released bacteriophage ssDNA leads to high local concentrations of the lanthanide ion carrier chelate and the antenna ligand, inducing formation of a fluorescent lanthanide chelate complex.

High-performance closed-tube PCR based on switchable luminescence probes.

We introduce a switchable lanthanide luminescence reporter technology based closed-tube PCR for the detection of specific target DNA sequence. In the switchable lanthanide chelate complementation based reporter technology hybridization of two nonfluorescent oligonucleotide probes to the adjacent positions of the complementary strand leads to the formation of a highly fluorescent lanthanide chelate complex. The complex is self-assembled from a nonfluorescent lanthanide chelate and a light-harvesting antenna ligand when the reporter molecules are brought into close proximity by the oligonucleotide probes.

Rapid homogeneous PCR assay for the detection of Chlamydia trachomatis in urine samples.

Chlamydia trachomatis infection is the most common bacterial sexually transmitted disease and a major public health problem worldwide. Fast and sensitive point-of-care diagnostics including non-invasive sample collection would be of value for the prevention of C. trachomatis transmission.