Miss Beverly Chen

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Research Assistant
Doctoral Candidate - Doctor of Philosophy

Research | Current

A Fully Implantable Optogenetic System for Chronic Animal Studies

Clinical problem

Optogenetics uses light to manipulate neural activity that has several advantages over conventional electrical stimulation approach including specific cell-type targeting with precise temporal precision, simultaneous stimulation using different wavelengths of light and is relatively harmless to targeted tissue.

In optogenetic experiments, targeted neurons are transfected with photo-sensitive proteins (opsins) for subsequent exciting or silencing neurons with pulses of visible light. The most commonly used to excite neural activity and alter behaviour in freely moving animals is Channelrhodopsin-2 (ChR). ChR2 is obtained from green algae named Chlamydomonas reinhardtii, which serves as sensory photoreceptors in the green algae. ChR2 can be activated with pulses of blue light (wavelength of ~470nm) to depolarize target neurons and evoke an action potential response. The development of inhibitory opsins called Halorhodopsin (NpHR), is obtained from archaebacterial named Natronomonas pharaonis. NpHR is an ion pump driven by red light (625nm), which can hyperpolarize neurons and therefore inhibit neural activity.

Optogenetic stimulation offers the prospect of treating lifetime conditions; however, current optogenetics available commercially are mainly connected with wires coming out of the head of the animal which brings a risk of infection and is vulnerable to damage from chewing or scratching. Also, current light stimulation systems are generally not suitable for chronic use due to the risk of infection associated with components located outside the brain. This study aims to investigate the technical feasibility of implementing a fully implantable optogenetics system supporting long-term light stimulation as well as for feasibility of wireless transmission of recorded signals outwards.

Illustration of the implantable optogenetic system.

Current Focus

A fully implantable optogenetic system has been developed for wavelengths of 470nm (blue) and 625nm (red). Blue light is suitable for exciting the ChR2 opsin and red light is suitable for inhibiting the NpHR opsin.


At the end of the project, we want to show that the fully implantable optogenetic system can improve neurological disorders such as Parkinson’s disease in an animal model after continuous light stimulation. This preliminary study will enable its use to be transferred from research to clinical studies.


Selected publications and creative works (Research Outputs)