Tag Archives: Jingxian Yu

Peptides as bio-inspired electronic materials

7 September 2018:

A new paper with CNBP authors Jingxian Yu, John Horsley and Andrew Abell extends fundamental knowledge of charge transfer dynamics and kinetics in peptides and also open up new avenues to design and develop functional bio-inspired electronic devices, such as on/off switches and quantum interferometers, for practical applications in molecular electronics.

Journal: Accounts of Chemical Research.

Publication title: Peptides as Bio-Inspired Electronic Materials: An Electrochemical and First-Principles Perspective.

Authors: Jingxian Yu, John R. Horsley, and Andrew D. Abell.

Abstract: Molecular electronics is at the forefront of interdisciplinary research, offering a significant extension of the capabilities of conventional silicon-based technology as well as providing a possible stand-alone alternative. Bio-inspired molecular electronics is a particularly intriguing paradigm, as charge transfer in proteins/peptides, for example, plays a critical role in the energy storage and conversion processes for all living organisms. However, the structure and conformation of even the simplest protein is extremely complex, and therefore, synthetic model peptides comprising well-defined geometry and predetermined functionality are ideal platforms to mimic nature for the elucidation of fundamental biological processes while also enhancing the design and development of single-peptide electronic components.

In this Account, we first present intramolecular electron transfer within two synthetic peptides, one with a well-defined helical conformation and the other with a random geometry, using electrochemical techniques and computational simulations. This study reveals two definitive electron transfer pathways (mechanisms), the natures of which are dependent on secondary structure. Following on from this, electron transfer within a series of well-defined helical peptides, constrained by either Huisgen cycloaddition, ring-closing metathesis, or a lactam bridge, was determined. The electrochemical results indicate that each constrained peptide, in contrast to a linear counterpart, exhibits a remarkable shift of the formal potential to the positive (>460 mV) and a significant reduction of the electron transfer rate constant (up to 15-fold), which represent two distinct electronic “on/off” states. High-level calculations demonstrate that the additional backbone rigidity provided by the side-bridge constraints leads to an increased reorganization energy barrier, which impedes the vibrational fluctuations necessary for efficient intramolecular electron transfer through the peptide backbone. Further calculations reveal a clear mechanistic transition from hopping to superexchange (tunneling) stemming from side-bridge gating. We then extended our research to fine-tuning of the electronic properties of peptides through both structural and chemical manipulation, to reveal an interplay between electron-rich side chains and backbone rigidity on electron transfer. Further to this, we explored the possibility that the side-bridge constraints present in our synthetic peptides provide an additional electronic transport pathway, which led to the discovery of two distinct forms of quantum interferometer. The effects of destructive quantum interference appear essentially through both the backbone and an alternative tunneling pathway provided by the side bridge in the constrained β-strand peptide, as evidenced by a correlation between electrochemical measurements and conductance simulations for both linear and constrained β-strand peptides. In contrast, an interplay between quantum interference effects and vibrational fluctuations is revealed in the linear and constrained 310-helical peptides.

Charge transfer in helical peptides

1 September 2017:

Understanding the electronic properties inherent to peptides is crucial for controlling charge transfer, and precursory to the design and fabrication of bio-inspired next generation electronic components.

However, to achieve this objective one must first be able to predict and control the associated charge transfer mechanisms.

Here CNBP researchers demonstrate for the first time a controllable mechanistic transition in peptides resulting directly from the introduction of a side-bridge.

Journal: RSC Advances.

Publication title: A controllable mechanistic transition of charge transfer in helical peptides: from hopping to superexchange.

Authors: Jingxian Yu (pictured), John R. Horsley and Andrew D. Abell.

For more information, access the paper here.

CNBP researcher at ICMAT and in China

5 July 2017:

CNBP Researcher, Dr Yu, from the University of Adelaide, presented recent findings on “Gating Electron Transfer in Peptides Towards Molecular Switches” at the International Conference on Materials for Advanced Technologies, commonly known as ICMAT 2017, held in Singapore, 18-24 June. It attracted more than 2,500 delegates from all over the world.

Following the ICMAT 2017, Dr Yu made a trip to Chongqing University, one of 985 project Universities in China. An invited lecture was given to the School of Chemistry and Chemical Engineering and he met with Professors Xiaohua Chen, Yi Xu, and Lingjie Li.

While in Chongqing, he also made a visit to the microfabrication facilities, including the MEMS, Wafer Lithography and clean room at the Centre of MicroFabrication and MicroSystems, Chongqing University. Networking provided a number of possible future collaborations.

Below – Dr Yu presenting CNBP science at Chongqing University.

Pilot project grant success

18 May 2017:

An ‘Institute for Photonics and Advanced Sensing’ (IPAS) pilot grant worth $6,000 has been awarded to CNBP researchers Dr Jingxian Yu (project lead – pictured left) and Dr Peipei Jia.

The grant will allow investigation into “double remote electrochemical addressing and optical readout of electrochemiluminescence at the nanopatterned tip of an optical fiber for the detection of biological species.”

The project has great potential to provide a versatile sensing platform for chemical sensing and medical diagnostics.

The proposed work will also bring chemists and physicists together to work in this trans-disciplinary area, with the possibility of promoting further collaborations between biological and medical scientists within IPAS and the CNBP.

A step towards bio-inspired quantum interferometers

Jingxian Yu_low_sq29 November 2016:

CNBP researchers (lead author Jingxian Yu pictured), have published a paper exploring the quantum interference effects on electronic transport in peptides. The work has just been reported in the journal ‘Molecular Systems Design & Engineering’ and is accessible online.

Journal: Molecular Systems Design & Engineering.

Title: Exploiting the interplay of quantum interference and backbone rigidity on electronic transport in peptides: A step towards bio-inspired quantum interferometers.

Authors: Jingxian Yu, John R Horsley and Andrew D Abell.

Abstract: Electron transfer in peptides provides an opportunity to mimic nature for applications in bio-inspired molecular electronics. However, quantum interference effects, which become significant at the molecular level, have yet to be addressed in this context. Electrochemical and theoretical studies are reported on a series of cyclic and linear peptides of both β-strand and helical conformation, to address this shortfall and further realize the potential of peptides in molecular electronics. The introduction of a side-bridge into the peptides provides both additional rigidity to the backbone, and an alternative pathway for electron transport. Electronic transport studies reveal an interplay between quantum interference and vibrational fluctuations. We utilize these findings to demonstrate two distinctive peptide-based quantum interferometers, one exploiting the tunable effects of quantum interference (β-strand) and the other regulating the interplay between the two phenomena (310-helix).

CNBP researcher at precision sensing workshop

Jingxian Yu_low_sq26 October 2016:

Dr Jingxian Yu, CNBP researcher has attended the Workshop on Precision Sensing for Defence, held at the Australian National University on October 23-25th 2016. The workshop was by invitation only with the aim of presenting and discussing Australia’s strengths in precision sensing technology, and to plan for collaborative arrangements to advance Australian precision sensing thorough the newly launched Next Generation Fund.

CNBP researcher at Gordon Research Conference

Jingxian Yu_low_sq5 June 2016:

CNBP Researcher, Dr Jingxian Yu, from the University of Adelaide, presented recent research on “Peptide-Based Quantum Interferometers and Their Sensing Applications” at the prestigious Gordon Research Conference on Electronic Processes in Organic Materials in Lucca, Italy, from 5-10 June 2016.

At the conference, chemists, physicists and materials scientists from all over the world addressed the key challenges in the field related to photophysical and charge transport processes in organic materials and discussed how molecular architectures could provide new and enhanced functionalities.

CNBP researcher visits China and Israel

Jingxian Yu_low_sq1 June 2016:

CNBP researcher from the University of Adelaide, Dr Jingxian Yu, was invited by several academic facilities in both China and Israel to disseminate his recent research. Lectures were given to the Department of Chemical Engineering at Xiamen University, China, Professor David Cahen’s group at the Weizmann Institute of Science, and the Department of Materials Engineering at Ben Gurion University of the Negev, Israel.

Whilst in China, Jingxian initialised the collaboration on electron transport in single molecules with Professor Wenjing Hong. He also met Professors Deying Wu, Shoufa Han, Dongping Zhan, and Jiawei Yan.

In Israel, he met Professors David Cahen, Mudi Sheves, Ron Naaman, and Drs Ayelet Vilan, Cunlan Guo, Sabyasachi Mukhopadhyay at the Weizmann Institute of Science, Professors Nurit Ashkenasy, Gonen Ashkenasy, Raz Jelinek, Hanna Rapaport and Drs Ronit Bitton, Mark Schvartzman, Hadar Ben Yoav, and Yifat Miller at the Ben Gurion University of the Negev. Networking provided a number of possible future collaborations.

Itinerary: Lectures:
June 1, 2016: School of Chemical Engineering, Xiamen University, China
June 13, 2016: Professor David Cahen Group, Weizmann Institute of Science, Israel.
June 14, 2016: Department of Materials Engineering at Ben Gurion University of the Negev, Israel

Jingxian Yu_China visit