Electrical antimicrobial susceptibility testing based on aptamer-functionalized capacitance sensor array for clinical isolates.

To prescribe effective antibiotics to patients with bacterial infections in a timely manner and to avoid the misuse of antibiotics, a rapid antimicrobial susceptibility test (AST) is essential. However, conventional AST methods require more than 16 h to provide results; thus, we developed an electrical AST (e-AST) system, which provides results within 6 h. The proposed e-AST is based on an array of 60 aptamer-functionalized capacitance sensors that are comparable to currently available AST panels and a pattern-matching algorithm.

Aptamer-functionalized capacitance sensors for real-time monitoring of bacterial growth and antibiotic susceptibility.

To prevent spread of infection and antibiotic resistance, fast and accurate diagnosis of bacterial infection and subsequent administration of antimicrobial agents are important. However, conventional methods for bacterial detection and antibiotic susceptibility testing (AST) require more than two days, leading to delays that have contributed to an increase in antibiotic-resistant bacteria. Here, we report an aptamer-functionalized capacitance sensor array that can monitor bacterial growth and antibiotic susceptibility in real-time.

A carbon nanotube metal semiconductor field effect transistor-based biosensor for detection of amyloid-beta in human serum.

We have developed a carbon nanotube (CNT) film-based biosensor with a metal semiconductor field effect transistor structure (MESFET). A gold top gate was deposited on the middle of the CNT channel and probe antibodies were immobilized on the gold top gate with an antibody-binding protein, protein G or Escherichia coli outer membrane (OM) with autodisplayed Z-domains of protein A. These CNT-MESFET biosensors exhibited a higher sensitivity than the CNT-FET biosensor with probe antibodies immobilized using a chemical linker, since the orientation of immobilized antibodies was controlled by the antibody-binding proteins.

Magnetic nanoparticle-based separation of metallic and semiconducting carbon nanotubes.

We report a simple and scalable method for the separation of semiconducting single-walled carbon nanotubes (SWNTs) from metallic SWNTs using magnetic nanoparticles (MNPs) functionalized with polycationic tri-aminated polysorbate 80 (TP80). MNPs-TP80 are selectively adsorbed on acid-treated semiconducting SWNTs, which makes the semiconducting SWNTs be highly concentrated to over 95% under a magnetic field. Almost all the field effect transistor network devices, which were fabricated using separated semiconducting SWNTs, exhibited a p-type semiconducting behavior with an on/off ratio of higher than 10(4).

Carbon nanotube-based dual-mode biosensor for electrical and surface plasmon resonance measurements.

We have developed carbon nanotube-based dual-mode biosensors with a metal semiconductor field effect transistor structure on a quartz substrate. DNA hybridization occurring on the Au top gate can be detected by simultaneously measuring the change in the electrical conductance and the surface plasmon resonance (SPR). Since electrical and SPR measurements offer high sensitivity and reliability, respectively, this dual-mode biosensor is expected to provide both of these features.