ABSTRACT
We report a simple and sensitive method for label-free detection of single-stranded DNA-binding protein (SSBP) based on an array of microfabricated cantilevers. The single-stranded DNA (ssDNA) was immobilized on the surface of the sensing cantilevers to detect SSBP, while the reference cantilevers were modified with 6-mercapto-1-hexanol to detect any unwanted cantilever deflection. The differential deflection signals that reveal specific SSBP-ssDNA binding have been found to depend on the SSBP concentration. Using the cantilever array sensor we can detect SSBP in the concentration range from 0.01 to 7 µg mL(-1). Other proteins, such as thrombin or bovine serum albumin induced no significant deflection of the cantilevers. Our results show the potential for the application of cantilever array sensor system as a powerful tool to detect proteins with high sensitivity and specificity.
Subject(s)
Biosensing Techniques/methods , DNA, Single-Stranded , DNA-Binding Proteins/analysis , Protein Array Analysis/methods , Biosensing Techniques/instrumentation , DNA, Single-Stranded/chemistry , DNA-Binding Proteins/chemistry , Equipment Design , Hexanols/chemistry , Protein Array Analysis/instrumentation , Protein Binding , Sensitivity and Specificity , Serum Albumin, Bovine/chemistry , Sulfhydryl Compounds/chemistry , Thrombin/chemistryABSTRACT
We present a new method for specific detection of oxytetracycline (OTC) at nanomolar concentrations based on a microfabricated cantilever array. The sensing cantilevers in the array are functionalized with self-assembled monolayers (SAMs) of OTC-specific aptamer, which acts as a recognition molecule for OTC. While the reference cantilevers in the array are functionalized with 6-mercapto-1-hexanol SAMs to eliminate the influence of environmental disturbances. The cantilever sensor shows a good linear relationship between the deflection amplitude and the OTC concentration in the range of 1.0-100 nM. The detection limit of the cantilever array sensor is as low as 0.2 nM, which is comparable to some traditional methods. Other antibiotics such as doxycycline and tetracycline do not cause significant deflection of the cantilevers. It is demonstrated that the cantilever array sensors can be used as a powerful tool to detect drugs with high sensitivity and selectivity.
