A Simple and Convenient Aptasensor for Protein Using an Electronic Balance as a Readout

Abstract

The electronic balance, one of the most common pieces of equipment in the laboratory, is normally used to directly measure the weight of a target with high accuracy. However, little attention has been paid to the extension of its applications. In this study, an electronic balance was used as a readout to develop a novel aptasensor for protein quantification for the first time. Thrombin was selected as a model target, and its two aptamers recognizing different sites of the protein were used (one aptamer was immobilized on the surface of magnetic microparticles and the other aptamer was functionalized with platinum nanoparticles). The two aptamers were specifically bound with the thrombin to form a sandwich structure; thus, the platinum nanoparticles were linked to the magnetic microparticles, and they were separated by a magnet easily. The captured platinum nanoparticles effectively catalyzed the decomposition of HO, generating a large volume of O to discharge a certain amount of water in a drainage device, because the pressure in the vial is higher than that outside of the vial. The weight of water was accurately measured by an electronic balance. The weight of water increased with the increasing of the thrombin concentration in the range of 0 to 100 nM with a detection limit of 2.8 nM. This is the first time the use of an electronic balance as a signal readout for biomolecule quantitation in bioassay has been reported.

Enhanced Thermometric Sensor for Arsenate Analysis Based on Dual Temperature Readout Signaling Strategy

“…Inspired by the previous POCT strategies based on different controlled release systems coupling with barometer, glucometer, and hand-held pH meter, we believe that this proposed system can be applied to build an effective signal conversion and amplification strategy to accelerate the development of a temperature and thermometer-based assay platform. Interestingly, it is notable that the increased pressure in an unsealed vessel, as a controlled release system, can be used for weighing water and developing an electronic balance-based sensing system. − According to this, we also found that our barometric system can lead to an obvious water overflowing result from the drainage device that connected with the O 2 -generation vessel, due to the increased pressure of the CoOOH nanoflakes mediated H 2 O 2 decomposition process. As a result, the overflowed H 2 O can be collected by a tube, and its amount may be easily measured by an electronic balance.…”

Nucleic Acids Analysis

“…As high as 18°C temperature change can be readout by thermometer and the detection limit of 0.28 nM was achieved without amplification. Besides, other handheld devices such as electronic balance [368], digital multimeter [369], uric acid meter [370], could also be used for nucleic acid analysis with appropriate signal transduction and signal amplification mechanism. The use of these handheld devices that are widely applied in daily life, opens a new door for simple, cost-effective, user-friendly and portable POC testing of nucleic acids with high specificity and sensitivity and without external bulky instrumentation.…”

The Development of an Amperometric Enzyme Biosensor Based on a Polyaniline-Multiwalled Carbon Nanocomposite for the Detection of a Chemotherapeutic Agent in Serum Samples from Patients

“…One of the most crucial characteristics of conducting polymers is their ability to reversibly alternate between the conducting and insulating electronic states by dopingundoping of ions [15][16][17][18][19][20]. Anions were shown to be the dopants in polyaniline films [21].…”