title: Optical fiber-based force transducer for microscale samples.
abstract: We discuss the design, instrumentation, and calibration of a versatile force transducer with feedback control, called the Micro-Extensional Rheometer (MER). A force range of eight decades (1-10(8) pN) and a displacement range of four decades (10-10(5) nm) with a spatial resolution of the order of nanometers are accessible with the instrument. A feedback-loop algorithm is used to control the commanded force or the extensional strain on the sample and implement different rheometric protocols such as step-strain, step-force, exponential strain, among others. The device may also be used to measure the forces exerted by active suspensions, pulling neurons, etc.
authors.affiliation: Biophysics Laboratory, Soft Condensed Matter Group, Raman Research Institute, Bangalore 560080, India.
authors.forename: R V
authors.initials: RV
authors.lastname: Seshagiri Rao
authors.forename: Chirag
authors.initials: C
authors.lastname: Kalelkar
authors.forename: Pramod A
authors.initials: PA
authors.lastname: Pullarkat
mesh_terms: D002138:Calibration; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D004926:Escherichia coli; D016014:Linear Models; D055616:Microtechnology / Q000295:instrumentation*; D055100:Optical Fibers; D012212:Rheology; D014159:Transducers
chemical_list: D004129:Dimethylpolysiloxanes; C013830:baysilon