Hyun-Heon Hwang

We report on a novel technique of resonant frequency shift measurement based on a nanomechanical cantilever with a PZT actuating layer for label-free detection of a prostate-specific antigen (PSA) in a liquid environment. The nanomechanical PZT thin film cantilever is composed of SiO(2)/Ta/Pt/PZT/Pt/SiO(2) on a SiN(x) supporting layer for simultaneous self-exciting and sensing; it was fabricated using a standard MEMS (micro electromechanical system) process. The specific binding characteristics

Recent research trends in biosensing have been geared toward developing bioanalytical devices that are label free, small in size, and portable and that can operate in a rapid manner. The performance of these devices has been dramatically improved through the advent of new materials and micro-/nanofabrication technologies. This is especially true for micro-/nanosized cantilever sensors, which undergo a change in mechanical properties upon the specific binding of biomolecules. In this review, we i

Nanomechanical microcantilevers have played a vital role in detecting biomolecular interactions. The ability of microcantilevers to detect biomolecular interactions is ascribed to the principle that the surface stress, caused by biomolecular interactions, dominates the dynamical response of the microcantilever. Here we have experimentally studied the correlation between biomolecular interactions and the dynamical response of microcantilevers. Moreover, the authors employed a mechanical beam mode

We developed an interdigitated microelectrode (IME) sensor system for blood-based Alzheimer's disease (AD) diagnosis based on impedimetric detection of amyloid-β (Aβ) protein, which is a representative candidate biomarker for AD. The IME sensing device was fabricated using a surface micromachining process. For highly sensitive detection of several tens to hundreds of picogram/mL of Aβ in blood, medium change from plasma to PBS buffer was utilized with signal cancellation and amplification proces

, is widely used in biosensors owing to its high sensitivity. However, in sensors detecting amyloid beta (Aβ), the redox reagent can cause the aggregation of Aβ, which is a disturbance factor in accurate detection. Here, we propose an interdigitated microelectrode (IME) based f-EIS technique that can alleviate the aggregation of Aβ and achieve high sensitivity by buffer control. The proposed method was verified by analyzing three different EIS-based sensors: non-faradaic EIS (nf-EIS), f-EIS, and

Given that reduced graphene oxide (rGO)-based biosensors allow disposable and repeatable biomarker detection at the point of care, we developed a wafer-scale rGO patterning method with mass productivity, uniformity, and high resolution by conventional micro-electro-mechanical systems (MEMS) techniques. Various rGO patterns were demonstrated with dimensions ranging from 5 μm up to several hundred μm. Manufacture of these patterns was accomplished through the optimization of dry etching conditions

Multiple target detection using a cantilever is essential for biosensor, chemical sensor, and electronic nose systems. We report a novel microcantilever array chip that includes four microreaction chambers in a chip, which consequently contains four different functionalized surfaces for multitarget detection. For model tests, we designed microcantilever chips and demonstrated the ability of binding of 2,4-dinitrotoluene (DNT) targets onto four different surfaces. We used peptide receptors that a