title: Constant-volume hydrogel osmometer: a new device concept for miniature biosensors.
abstract: A new type of biosensor is proposed that combines the recognition properties of "intelligent" hydrogels with the sensitivity and reliability of microfabricated pressure transducers. In the proposed device, analyte-induced changes in the osmotic swelling pressure of an environmentally responsive hydrogel are measured by confining it within a small implantable enclosure between a rigid semipermeable membrane and the diaphragm of a miniature pressure transducer. Proof-of-principle tests of this device were performed in vitro using pH-sensitive hydrogels, with osmotic deswelling data for the same hydrogels used as a benchmark for comparison. The swelling pressure of the hydrogel was accurately determined from osmotic deswelling measurements against reservoirs of known osmotic stress. Values of swelling pressure vs salt concentration measured with a preliminary version of the sensor agree well with osmotic deswelling results. Through modification of the hydrogel with various enzymes or pendant binding moieties, the sensor has the potential to detect a wide range of biological analytes with good specificity.
authors.affiliation: M-Biotech Inc., 2411 South 1070 West, Suite C, Salt Lake City, Utah 84119, USA. m-biotech@m-biotech.com
authors.forename: In Suk
authors.initials: IS
authors.lastname: Han
authors.forename: Man-Hee
authors.initials: MH
authors.lastname: Han
authors.forename: Jinwon
authors.initials: J
authors.lastname: Kim
authors.forename: Seok
authors.initials: S
authors.lastname: Lew
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: Lee
authors.forename: Ferenc
authors.initials: F
authors.lastname: Horkay
authors.forename: Jules J
authors.initials: JJ
authors.lastname: Magda
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D020100:Hydrogels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008904:Miniaturization; D009997:Osmotic Pressure; D012965:Sodium Chloride; D013816:Thermodynamics; D014159:Transducers
chemical_list: D020100:Hydrogels; D012965:Sodium Chloride