Deciphering the Roles of Interfacial Amino Acids in Inter-Protein Charge Transport.

Elucidating charge transport (CT) through proteins is critical for gaining insights into ubiquitous CT chain reactions in biological systems and developing high-performance bioelectronic devices. While intra-protein CT has been extensively studied, crucial knowledge about inter-protein CT via interfacial amino acids is still absent due to the structural complexity. Herein, by loading cytochrome c (Cyt c) on well-defined peptide self-assembled monolayers to mimic the protein-protein interface, we provide a precisely controlled platform for identifying the roles of interfacial amino acids in solid-state CT via peptide-Cyt c junctions. The terminal amino acid of peptides serves as a fine-tuning factor for both the interfacial interaction between peptides and Cyt c and the immobilized Cyt c orientation, resulting in a nearly 10-fold difference in current through peptide-Cyt c junctions with varied asymmetry. This work provides a valuable platform for studying CT across proteins and contributes to the understanding of fundamental principles governing inter-protein CT.

Peptide-Based Electrical Array Sensor for Discriminating Heavy Metal Ions.

Charge transport in molecular junctions provides an excellent way to investigate the response of molecules to intrinsic changes and external stimuli, exhibiting powerful potential for developing sensors. However, achieving multianalyte recognition remains a challenge. Herein, we innovatively developed an electrical array sensor based on peptide self-assembled layers for discriminating various heavy metal ions. Three peptide sequences were designed as sensing units with varying binding affinities for different metal ions. Electrical measurements demonstrated that different metal ions diversely affect the charge transport of peptide junctions. By using principal component analysis, a clear discrimination between the five kinds of heavy metal ions can be achieved. In the analysis of real samples, the array sensor showed a reliable anti-interference capability. The array sensor offers possibilities for large-area molecular junctions to construct functional molecular sensing devices.

A D-Band Direct-Conversion IQ Receiver with 28 dB CG and 7.3 dB NF in 130 nm SiGe Process.

In this paper, a D-band direct conversion IQ receiver with on-chip multiplier chain is presented. The D-band LNA with gain-boosting and stagger-tunning technique is implemented to provide high gain and large bandwidth. X9 multiplier chain including Marchand balun and quadrature (90°) hybrid is employed to provide four path LO signal to drive IQ mixer. This receiver is implemented in a 130nm SiGe process and consumes a core area of 1.04 mm2. From the experimental results, the proposed receiver exhibits a 20 GHz bandwidth from 150 GHz to 170 GHz, with CG of 28 dB and NF of 7.3 dB at 158 GHz.