A microcantilever‐based pathogen detector

Abstract

Summary:The ability to detect small amounts of materials, especially bacterial organisms, is important for medical diagnostics and national security issues. Engineered micromechanical systems provide one approach for constructing multifunctional, highly sensitive, real-time, immunospecific biological detectors. We present qualitative detection of specific Salmonella enterica strains using a functionalized silicon nitride microcantilever. Detection is achieved due to a change in the surface stress on the cantilever surface in situ upon binding of a small number of bacteria. Scanning electron micrographs indicate that less than 25 adsorbed bacteria are required for detection.

Impression creep behaviour of magnesium alloy-based hybrid composites in the longitudinal direction

“…Such high values of the apparent stress exponent, na, cannot be explained based on the existing deformation models. The discontinuously reinforced metal matrix composites (DRMMCs) are known to exhibit high values of apparent stress exponent, na [17,[34][35][36], which has been attributed to the existence of a threshold stress, r0. The threshold stress is de-fined as a lower limiting stress below which no measurable strain rate can be achieved [37].…”

Cantilever biosensors for detection of viruses and bacteria

“…Видимо связывание таких больших объектов как бактерии не создает на поверхности равномерного поверхностного напряжения. Для бактерии S.Typhimurium кантилевер в резонансном режиме показал предел обнаружения на уровне 5•10 3 клеток/мл [16], а в режиме измерения поверх ностного напряжения -10 6 КОЕ/мл [17]. Кэмпбелл и соавторы использовали кантилевер, модифици рованный поликлональными антителами к бак терии B. Anthracis, для измерения в потоке и пока зали чувствительность в 300 спор/мл [18].…”

“…Apparently the binding of such large objects as the bacteria does not create a uniform surface tension. For the S.Typhimurium bacteria the can tilever in resonance mode showed a detection limit at the level of 5•10 3 cells/ml [16], and in the mode of measur ing of surface ten sion -10 6 CFU/ml [17]. Campbell and co authors used a cantilever mod ified with polyclonal antibodies against B.Anthracis bacteria for measuring in the flow and have shown a sensitivity of 300 spores/ml [18].…”

Optical Lever Based Parylene Cantilevers for Biochemical Sensing

“…Cantilever sensors can operate in either resonant mode (resonant frequency shift) or static mode (static bending). Because of its ability to operate in both liquid and air, the static mode operation is becoming especially attractive [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The enthusiasm on such kind of sensor is mainly because it has advantages such as label-free detection, simple sensor structure, high sensitivity, etc.…”