A brain–machine interface (BMI) is a device that translates neuronal information into commands capable of controlling external software or hardware such as a computer or robotic arm. BMIs are often used as assisted living devices for individuals with motor or sensory impairments. Retinal prostheses for restoration of sight to patients blinded by retinal degeneration are being developed by a number of private companies and research institutions worldwide. The system is meant to partially restore useful vision to people who have lost their photoreceptors due to retinal diseases such as retinitis pigmentosa (RP) or age-related macular degeneration (AMD). Three types of retinal implants are currently in clinical trials: epiretinal (on the retina), subretinal (behind the retina), and suprachoroidal (between the choroid and the sclera). Retinal implants introduce visual information into the retina by electrically stimulating the surviving retinal neurons. So far, elicited percepts had rather low resolution, and may be suitable for light perception and recognition of simple objects. I developed the NanowireRetina—a new generation of implantable artificial retina to restore vision. This breakthrough also pioneered the development of nanowire arrays for retinal implants. The restoration of light response with complex spatiotemporal features in retinal degenerative diseases towards retinal prosthesis has proven to be a considerable challenge over the past decades. Herein, inspired by the structure and function of photoreceptors in retinas, I develop artificial photoreceptors based on gold nanoparticle-decorated titania nanowire arrays, for restoration of visual responses in the blind mice with degenerated photoreceptors. Green, blue and near UV light responses in the retinal ganglion cells (RGCs) are restored with a spatial resolution better than 100 µm. ON responses in RGCs are blocked by glutamatergic antagonists, suggesting functional preservation of the remaining retinal circuits. Moreover, neurons in the primary visual cortex respond to light after subretinal implant of nanowire arrays. Improvement in pupillary light reflex suggests the behavioral recovery of light sensitivity. My study will shed light on the development of a new generation of optoelectronic toolkits for subretinal prosthetic devices. Through pharmacological, optical, ultrasound and electrical toolsets, I aim to develop effective therapeutic solutions to neurological disease states.
Shining Light on the Nervous System: from Biomaterials to Bioelectronics
Neurological disorder is a complex medical problem that can have profound effects on your physical and mental well-being. My goal is to help you decrease your level of pain and suffering, to return you to your maximum level of functioning and independence, and to help you restore your quality of life. I developed a light triggered smart drug release device system. Current treatments of pain heavily rely on opioids, resulting in significant side effects such as addiction, tolerance, leading to the Opioid Overdose Crisis as we know of today. Smart drug delivery systems may provide an effective solution. Here I present the development of externally-triggerable drug delivery systems for on-demand, repeatable and adjustable local anesthesia using new polymer nanoparticles, where the timing, duration, and intensity of nerve block can be controlled through external energy triggers such as the optical tool. In addition to traditional pharmacological approaches, bioelectronic platforms to enhance our insights into the retina.
Biosensors for Health Monitoring and Early Diagnosis
Precision Health reimagines medicine to focus on predicting, preventing, and curing disease precisely. Marrying two seemingly different approaches-high-tech and high-touch-this vision tailors health care to the unique biology and life circumstances of each individual, with an emphasis on catching disease before it strikes. Precision Health represents a fundamental shift to more proactive and personalized care that empowers people to lead healthy lives. The evolution of photoelectrochemical (PEC) bioanalysis has resulted in substantial progress in its analytical performance and biodetection applications. PEC sensor represents a unique means for chemical and biological detection, with foci of optimizing semiconductor composition and electronic structures, surface functionalization layers, and chemical detection methods. Here, I have briefly discussed my recent developments of nanowire‐based PEC sensing, with particular emphasis on three main detection mechanisms and corresponding examples. I have also demonstrated the use of the PEC sensing of real‐time molecular reaction kinetic measurements, as well as direct interfacing of living cells and probing of cellular functions. My work will serve as a useful source to inform the interested audience of the latest developments and applications in the field of PEC bioanalysis.