Optimizing bead size reduces errors in force measurements in optical traps.
Opt Express
; 21(1): 39-48, 2013 Jan 14.
Article
en En
| MEDLINE
| ID: mdl-23388894
ABSTRACT
Optical traps are used to measure force (F) over a wide range (0.01 to 1,000 pN). Variations in bead radius (r) hinder force precision since trap stiffness (k(trap)) varies as r3 when r is small. Prior work has shown k(trap) is maximized when r is approximately equal to the beam waist (w0), which on our instrument was ~400 nm when trapping with a 1064-nm laser. In this work, we show that by choosing r ≈w0, we improved the force precision by 2.8-fold as compared to a smaller bead (250 nm). This improvement in force precision was verified by pulling on a canonical DNA hairpin. Thus, by using an optimum bead size, one can simultaneously maximize k(trap) while minimizing errors in F.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Biofisica
/
ADN
/
Óptica y Fotónica
/
Conformación de Ácido Nucleico
Idioma:
En
Revista:
Opt Express
Asunto de la revista:
OFTALMOLOGIA
Año:
2013
Tipo del documento:
Article
País de afiliación:
Estados Unidos