Browsing by Author "Yanik, C."

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Open Access
Atmospheric pressure mass spectrometry of single viruses and nanoparticles by nanoelectromechanical systems
(American Chemical Society, 2022-01-04) Erdogan, R. Tufan; Alkhaled, Mohammed; Kaynak, Batuhan E.; Alhmoud, Hashim; Pisheh, Hadi Sedaghat; Kelleci, Mehmet; Karakurt, Ilbey; Yanik, C.; Şen, Zehra Betül; Sari, B.; Yagci, A. M.; Özkul, A.; Hanay, M. Selim
Mass spectrometry of intact nanoparticles and viruses can serve as a potent characterization tool for material science and biophysics. Inaccessible by widespread commercial techniques, the mass of single nanoparticles and viruses (>10MDa) can be readily measured by nanoelectromechanical systems (NEMS)-based mass spectrometry, where charged and isolated analyte particles are generated by electrospray ionization (ESI) in air and transported onto the NEMS resonator for capture and detection. However, the applicability of NEMS as a practical solution is hindered by their miniscule surface area, which results in poor limit-of-detection and low capture efficiency values. Another hindrance is the necessity to house the NEMS inside complex vacuum systems, which is required in part to focus analytes toward the miniscule detection surface of the NEMS. Here, we overcome both limitations by integrating an ion lens onto the NEMS chip. The ion lens is composed of a polymer layer, which charges up by receiving part of the ions incoming from the ESI tip and consequently starts to focus the analytes toward an open window aligned with the active area of the NEMS electrostatically. With this integrated system, we have detected the mass of gold and polystyrene nanoparticles under ambient conditions and with two orders-of-magnitude improvement in capture efficiency compared to the state-of-the-art. We then applied this technology to obtain the mass spectrum of SARS-CoV-2 and BoHV-1 virions. With the increase in analytical throughput, the simplicity of the overall setup, and the operation capability under ambient conditions, the technique demonstrates that NEMS mass spectrometry can be deployed for mass detection of engineered nanoparticles and biological samples efficiently.
Open Access
Dynamics of NEMS resonators across dissipation limits
(AIP Publishing LLC, 2022-07-12) Ti, C.; McDaniel, J. G.; Liem, A.; Gress, H.; Ma, M.; Kyoung, S.; Svitelskiy, O.; Yanik, C.; Kaya, I. I.; Hanay, M. S.; González, M.; Ekinci, K. L.
The oscillatory dynamics of nanoelectromechanical systems (NEMS) is at the heart of many emerging applications in nanotechnology. For common NEMS, such as beams and strings, the oscillatory dynamics is formulated using a dissipationless wave equation derived from elasticity. Under a harmonic ansatz, the wave equation gives an undamped free vibration equation; solving this equation with the proper boundary conditions provides the undamped eigenfunctions with the familiar standing wave patterns. Any harmonically driven solution is expressible in terms of these undamped eigenfunctions. Here, we show that this formalism becomes inconvenient as dissipation increases. To this end, we experimentally map out the position- and frequency-dependent oscillatory motion of a NEMS string resonator driven linearly by a non-symmetric force at one end at different dissipation limits. At low dissipation (high Q factor), we observe sharp resonances with standing wave patterns that closely match the eigenfunctions of an undamped string. With a slight increase in dissipation, the standing wave patterns become lost, and waves begin to propagate along the nanostructure. At large dissipation (low Q factor), these propagating waves become strongly attenuated and display little, if any, resemblance to the undamped string eigenfunctions. A more efficient and intuitive description of the oscillatory dynamics of a NEMS resonator can be obtained by superposition of waves propagating along the nanostructure.
Open Access
Multimode brownian dynamics of a nanomechanical resonator in a viscous fluid
(American Physical Society, 2023-10-24) Gress, H.; Barbish, J.; Yanik, C.; Kaya, I.I.; Erdoğan, Ramazan Tufan; Hanay, Mehmet Selim; González, M.; Svitelskiy, O.; Paul, M.R.; Ekinci, K.L.
Brownian motion imposes a hard limit on the overall precision of a nanomechanical measurement. Here, we present a combined experimental and theoretical study of the Brownian dynamics of a quintessential nanomechanical system, a doubly clamped nanomechanical beam resonator, in a viscous fluid. Our theoretical approach is based on the fluctuation-dissipation theorem of statistical mechanics: we determine the dissipation from fluid dynamics; we incorporate this dissipation into the proper elastic equation to obtain the equation of motion; and the fluctuation-dissipation theorem then directly provides an analytical expression for the position-dependent power spectral density (PSD) of the displacement fluctuations of the beam. We compare our theory to experiments on nanomechanical beams immersed in air and water and obtain excellent agreement. Within our experimental parameter range, the Brownian-force noise driving the nanomechanical beam has a colored PSD due to the "memory"of the fluid; the force noise remains mode independent and uncorrelated in space. These conclusions are not only of interest for nanomechanical sensing but also provide insight into the fluctuations of elastic systems at any length scale.
Open Access
Vapor sensing of colorectal cancer biomarkers in isolation by bare and functionalized nanoelectromechanical sensors
(Institute of Electrical and Electronics Engineers, 2023-08-04) Karakan, M. C.; Ari, Atakan B.; Kelleci, M.; Yanik, C.; Kaya, I. I.; Tastan, O.; Hanay, M. Selim
Small dimensions and high resonance frequencies render nanoelectromechanical systems (NEMS) sensitive mass detectors. Mass detection capability can be used to sense chemicals in the gas phase by functionalizing the device, usually with a polymeric film. The performance of NEMS-based gas detectors in breath analysis applications depends crucially on the selectivity between selected functionalization layers and targeted biomarkers. Here, we report the detection of four colorectal cancer biomarkers at parts-per-million concentration levels, when introduced in isolation to the sensor system within a dry nitrogen stream. The biomarkers, 3-methylpentane, cyclohexane, nonanal, and decanal, were then discriminated from each other by using the combined response of three NEMS devices: one bare device, and two devices coated with either poly(ethyleneoxide) or poly(caprolactone). Our results indicate that bare NEMS are more responsive to high molar mass biomarkers, whereas functionalized sensors are more responsive toward more volatile biomarkers. Considering the inherently fast response times and minuscule limits of detection of NEMS devices, the combined response of differentially coated sensors can be used as the main sensing element to identify and distinguish cancer biomarkers in human breath.