In analogy to the role of long-chain polyamines in biosilicification, poly-L-lysine facilitates the assembly of nanocomponents to design multifunctional microcapsule structures. The method is demonstrated by the fabrication of a magnetically separable catalyst that accommodates Pd nanoparticles (NPs) as active catalyst, Fe3O4 NPs as magnetic component for easy recovery of the catalyst, and silica NPs to impart stability and selectivity to the catalyst. In addition, polyamines embedded inside the microcapsule prevent the agglomeration of Pd NPs and thus result in efficient catalytic activity in hydrogenation reactions, and the hydrophilic silica surface results in selectivity in reactions depending on the polarity of substrates.

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In this work gate-on-drain L-shaped channel Tunnel FET is proposed to detect various biomolecules through label-free bio-sensing detection technique. Biomolecules can be detected in the proposed structure through modulation of ambipolar current between channel and drain. Modulation of ambipolar current is performed by extending gate over drain in order to create a gate to drain overlap (cavity) by etching the specific portion of the gate. Trapped biomolecules within cavity gets immobilized. Immobilized biomolecules change the drain to channel tunneling width, thus changing the ambiploar leakage current. Drain doping and cavity length was fine-tuned to achieve better sensitivity in terms of ambipolar current and ambipolar knee voltage shift with and without presence of biomolecules. A maximum sensitivity of 3.8 × 10 7 is achieved for drain doping of 5 × 10 19 donors/cm 3 and cavity length of 60 nm. A high value of sensitivity is achieved for each biomolecules when drain doping ranged from 10 19 donors/cm 3 to 5 × 10 19 donors/cm 3 and cavity length ranged between 40 nm to 50 nm. Effect of differently charged biomolecules on sensitivity has also be structured.

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