Microsystem Technology

We present liquid-cell transmission electron microscopy (liquid-cell TEM) imaging of fixed and non-fixed prostate cancer cells (PC3 and LNCaP) with high resolution in a custom developed silicon nitride liquid cell. Fixed PC3 cells were imaged for 90–120 min without any discernable damage. High contrast on the cellular structures was obtained even at low electron doses (~2.5 e − /nm 2 per image). The images show distinct structures of cell compartments (nuclei and nucleoli) and cell boundaries without any further sample embedding, dehydration, or staining. Furthermore, we observed dynamics of vesicles trafficking from the cell membrane in consecutive still frames in a non-fixed cell. Our findings show that liquid-cell TEM, operated at low electron dose, is an excellent tool to investigate dynamic events in non-fixed cells with enough spatial resolution (few nm) and natural amplitude contrast to follow key intracellular processes.

— We report on a lab-on-chip sensor system based on integrated-optical resonators. The photonic components were realized in CMOS-process compatible amorphous silicon and the microfluidic interface enabling directed analyte transport was fabricated with soft-lithography technology. The developed sensor features optical resonators with dispersion engineered resonance spectra (DERS) to match optical resonance peaks over a wavelength region of several free spectral ranges. Resonance shifts caused by changes in refractive index of the investigated analyte are tracked by red-shifting a reference spectrum through the thermo-optic effect using electrical micro-heaters. With the DERS preserving the unambiguousness of the direct proportional relation between resonance shift and necessary heating power, this sensing principle enables direct electronic readout of analyte property changes. The sensor system therefore reduces the number and the size of peripheral devices usually necessary for the analysis of integrated optical devices, resulting in a broader range of potential application scenarios.

— We report on a lab-on-chip sensor system based on integrated-optical resonators. The photonic components were realized in CMOS-process compatible amorphous silicon and the microfluidic interface enabling directed analyte transport was fabricated with soft-lithography technology. The developed sensor features optical resonators with dispersion engineered resonance spectra (DERS) to match optical resonance peaks over a wavelength region of several free spectral ranges. Resonance shifts caused by changes in refractive index of the investigated analyte are tracked by red-shifting a reference spectrum through the thermo-optic effect using electrical micro-heaters. With the DERS preserving the unambiguousness of the direct proportional relation between resonance shift and necessary heating power, this sensing principle enables direct electronic readout of analyte property changes. The sensor system therefore reduces the number and the size of peripheral devices usually necessary for the analysis of integrated optical devices, resulting in a broader range of potential application scenarios.

We present liquid-cell transmission electron microscopy (liquid-cell TEM) imaging of fixed and non-fixed prostate cancer cells (PC3 and LNCaP) with high resolution in a custom developed silicon nitride liquid cell. Fixed PC3 cells were imaged for 90–120 min without any discernable damage. High contrast on the cellular structures was obtained even at low electron doses (~2.5 e−/nm2 per image). The images show distinct structures of cell compartments (nuclei and nucleoli) and cell boundaries without any further sample embedding, dehydration, or staining. Furthermore, we observed dynamics of vesicles trafficking from the cell membrane in consecutive still frames in a non-fixed cell. Our findings show that liquid-cell TEM, operated at low electron dose, is an excellent tool to investigate dynamic events in non-fixed cells with enough spatial resolution (few nm) and natural amplitude contrast to follow key intracellular processes.

The gaping hole left by the absence of a fourth fundamental circuit element to bridge the gap between charge and magnetic flux was finally filled in 1971 when Leon Chua theorized the existence of memristors. Though his paper was nothing shy of complexity and ingenuity, it was left largely unappreciated until in 2008 when Stanley Williams and his team at Hewlett-Packard’s (HP) Labs realized the memristor in device form. Despite the fact that the relationships governing the behavior of HP’s titanium dioxide (TiO2) memristor have already been stated, this paper takes a radical and simpler spin on deriving equivalent relations. The equations illustrating the relationship between charge-magnetic flux and current-voltage for memristor are derived using the Drude Model of electrical conduction. Several assumptions are taken into account while using this approach, and the end equations obtained are utilized to simulate the characteristic curves of memristor using MATLAB.