Intravital fluorescence imaging of mouse brain using implantable semiconductor devices and epi-illumination of biological tissue (original) (raw)
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Japanese Journal of Applied Physics, 2007
In our previous work, we demonstrated the potential of a complementary metal-oxide-semiconductor (CMOS) imaging device for use in imaging of the mouse brain. We showed that the device is capable of detecting fluorescence signal inside the mouse brain and successfully imaged real-time protease activity inside the hippocampus. In this work, we have improved the imaging device by integrating an excitation light source in the form of an ultraviolet light-emitting diode chip and an injection needle onto the sensor chip. This results in a compact single device imaging system for minimal invasive imaging inside the mouse brain. Also experimental repeatability is improved which enabled us to successful perform calibration of fluorophore concentration using the device. Fluorescence imaging experiments inside the brain phantom as well as in the mouse brain show that the device is capable of real time fluorescence detection. Using the device, we found that diffusion rate of chemical injected into the brain is smaller than 10 pmol/min. This work is expected to lead to the successful use of a CMOS imaging device for the study of the functions of the brain.
Optics express, 2012
We developed a complementary metal oxide semiconductor (CMOS) integrated device for optogenetic applications. This device can interface via neuronal tissue with three functional modalities: imaging, optical stimulation and electrical recording. The CMOS image sensor was fabricated on 0.35 μm standard CMOS process with built-in control circuits for an on-chip blue light-emitting diode (LED) array. The effective imaging area was 2.0 × 1.8 mm². The pixel array was composed of 7.5 × 7.5 μm² 3-transistor active pixel sensors (APSs). The LED array had 10 × 8 micro-LEDs measuring 192 × 225 μm². We integrated the device with a commercial multichannel recording system to make electrical recordings.
Implantable Fluorescence Imager for Deep Neuronal Imaging
2021
Implantable Fluorescence Imager for Deep Neuronal Imaging Jaebin Choi This thesis describes the design, fabrication, and characterization of the Implantable Fluorescence Imager (IFI): a camera chip with a needle-like form factor designed for imaging neuronal activity in the deep brain. It is fabricated with a complementary metal oxide semiconductor (CMOS) process, allowing for hundreds or thousands of singlephoton-sensitive photodetectors to be densely packed onto a device width comparable to a single-channel fiber optic cannula (~100 µm). The IFI uses a combination of spectral and temporal filters as a fluorescence emission filter, and per-pixel Talbot gratings for 3D light-field imaging. The IFI has the potential to overcome the imaging depth limit of multi-photon microscopes imposed by the scattering and absorption of photons in brain tissue, and the resolution limit of noninvasive imaging techniques, such as functional magnetic resonance imaging and photoacoustic imaging. It competes with graded index lens-based miniaturized microscopes in imaging depth, but offers several comparative advantages. First, its cross sectional area is at least an order of magnitude smaller for an equal field of view. Second, the distribution of pixels along its entire length allows the study of multilayer or multi-region dynamics. Finally, the scalability advantage of silicon integrated circuit technology in system miniaturization and data bandwidth may allow thousands of such imaging shanks to be simultaneously deployed for large-scale volumetric recording. List of Figures 1.1 Brain Complexity, "Brain Fields," and Structural Length Scales Visa -Vis Cell-Body Location, Density, and Heterogeneity in the Rodent Brain. (A) Biophysical scales for electrical, neurochemical, and optical domain recordings and relative sizes of brain structures. (B) A~2 µm thick optical section of an adult rat brain slice, stained with a fluorescent nuclear stain, wet mounted, and imaged by large-scale serial two-photon microscopy. Beneath this image, we enumerate three "brain fields"-that is, domains of neural activity: the electrical, neurochemical, and mechanical. (C-E) Cellular nuclear density at multiple scales (C, 500 µm; D, 200 µm; E, 20 µm), from the macroscopic down to the level of individual cells.
Integrated semiconductor optical sensors for cellular and neural imaging
2007
Intrinsic Optical Signal (IOS) imaging is a widely accepted technique for imaging brain activity. We propose an integrated device consisting of interleaved arrays of gallium arsenide (GaAs) based semiconductor light sources and detectors operating at telecommunications wavelengths in the nearinfrared. Such a device will allow for long-term, minimally invasive monitoring of neural activity in freely behaving subjects, and will enable the use of structured illumination patterns to improve system performance. In this work we describe the proposed system and show that near-infrared IOS imaging at wavelengths compatible with semiconductor devices can produce physiologically significant images in mice, even through skull.
Functional brain fluorescence plurimetry in rat by implantable concatenated CMOS imaging system
Biosensors and Bioelectronics, 2014
Measurement of brain activity in multiple areas simultaneously by minimally invasive methods contributes to the study of neuroscience and development of brain machine interfaces. However, this requires compact wearable instruments that do not inhibit natural movements. Application of optical potentiometry with voltage-sensitive fluorescent dye using an implantable image sensor is also useful. However, the increasing number of leads required for the multiple wired sensors to measure larger domains inhibits natural behavior. For imaging broad areas by numerous sensors without excessive wiring, a web-like sensor that can wrap the brain was developed. Kaleidoscopic potentiometry is possible using the imaging system with concatenated sensors by changing the alignment of the sensors. This paper describes organization of the system, evaluation of the system by a fluorescence imaging, and finally, functional brain fluorescence plurimetry by the sensor. The recorded data in rat somatosensory cortex using the developed multiple-area imaging system compared well with electrophysiology results.
An Implantable CMOS Image Sensor with Light Guide Array Structure and Fluorescent Filter
Abstract—We fabricated an implantable CMOS image sensor with a light guide array and an interference filter for high spatial resolution fluorescent imaging in a brain. By using a light guide array, incident angle of light into the pixel array of the image sensor is limited and spatial resolution degradation with the spacing between the sensor and a sample is reduced. We demonstrate spatial resolution improvement and wavelength selectivity by the fabricated image sensor.
Scientific Reports, 2016
To better understand the brain function based on neural activity, a minimally invasive analysis technology in a freely moving animal is necessary. Such technology would provide new knowledge in neuroscience and contribute to regenerative medical techniques and prosthetics care. An application that combines optogenetics for voluntarily stimulating nerves, imaging to visualize neural activity, and a wearable micro-instrument for implantation into the brain could meet the abovementioned demand. To this end, a micro-device that can be applied to the brain less invasively and a system for controlling the device has been newly developed in this study. Since the novel implantable device has dual LEDs and a CMOS image sensor, photostimulation and fluorescence imaging can be performed simultaneously. The device enables bidirectional communication with the brain by means of light. In the present study, the device was evaluated in an in vitro experiment using a new on-chip 3D neuroculture with an extracellular matrix gel and an in vivo experiment involving regenerative medical transplantation and gene delivery to the brain by using both photosensitive channel and fluorescent Ca 2+ indicator. The device succeeded in activating cells locally by selective photostimulation, and the physiological Ca 2+ dynamics of neural cells were visualized simultaneously by fluorescence imaging. Understanding the functional neural cells activities in the brain that are related to psychological and physical activities is one of the most important issues in neuroscience today. Noninvasive optical methods are useful, powerful tools for functional brain analysis, because such methods enable wide-ranging analyses with high spatiotemporal resolution without destroying tissue. A number of such tools have recently been developed. Optogenetics is spatially and temporally precise, which allows specific cells of living tissue to be selectively targeted 1-3. A gene of a photosensitive channel protein confers light responsiveness to the transfected cell. In other words, the genetically encoded switches allow neurons to be turned on or off with light of certain wavelengths. In addition, neural activity can be stably visualized in broad areas using a genetically encoded Ca 2+ indicator, which shows the intracellular calcium status as changes in fluorescence intensity 4-6. Such an indicator permits constant long-term imaging without quenching, drift, or reloading upon every measurement, unlike dye-type indicators. Several instruments that photostimulate neurons in the brain with optogenetics have recently been developed 7-9 , in addition to several functional brain-imaging techniques 10-14. Micro complementary-metal-oxide-semiconductor (CMOS) image sensors enable less invasive imaging in living tissue 15-21. Previous studies have demonstrated that a fluorescence imaging system enables potentiometry in primary cultured neurons and in the brain with multiple sensors 22-25. These compact instruments for functional brain measurements in a freely moving animal, incorporating optogenetics and Ca 2+ imaging, will provide insight into the natural behavior of animals. Such a technique would be
Pulse modulation CMOS image sensor for bio-fluorescence imaging applications
2005 IEEE International Symposium on Circuits and Systems
For wide dynamic range, compatibility with digital circuits, and low-voltage operation, the pulse modulation technique is suitable for an implanted bioimage sensor. We demonstrate bio-fluorescence imaging of the hippocampus in a sliced mouse brain using a pulse modulation-based image sensor. The sensor architecture and system configuration are discussed. In addition, we develop an imaging device for implantation into a mouse brain in order to measure the neural activity in the hippocampus. The device is composed of a pulse modulation image sensor with 128×128 pixels and a fiber illuminator on a polyimide substrate.
Optical brain imaging using a semi-transparent organic light-emitting diode
arXiv, 2020
https://arxiv.org/abs/2010.14287 arXiv:2010.14287 We report optical brain imaging using a semi-transparent organic light-emitting diode (OLED) based on the orange light-emitting polymer (LEP) Livilux PDO-124. The OLED serves as a compact, extended light source which is capable of uniformly illuminating the cortical surface when placed across a burr hole in the skull. Since all layers of the OLED are substantially transparent to photons with energies below the optical gap of the LEP, light emitted or reflected by the cortical surface may be efficiently transmitted through the OLED and into the objective lens of a low magnification microscope ("macroscope"). The OLED may be placed close to the cortical surface, providing efficient coupling of incident light into the brain cavity; furthermore, the macroscope may be placed close to the upper surface of the OLED, enabling efficient collection of reflected/emitted light from the cortical surface. Hence the use of a semi-transparent OLED simplifies the optical setup, while at the same time maintaining high sensitivity. The OLED is applied here to one of the most demanding forms of optical brain imaging, namely extrinsic optical imaging involving a voltage sensitive dye (VSD). Specifically, we carry out functional imaging of the primary visual cortex (V1) of a rat, using the voltage sensitive dye RH-1691 as a reporter. Imaging through the OLED light-source, we are able to resolve small (~ 0.1 %) changes in the fluorescence intensity of the dye due to changes in the neuronal membrane potential following a visual stimulus. Results are obtained on a single trial basis-i.e. without averaging over multiple measurements-with a time-resolution of ten milliseconds. https://arxiv.org/abs/2010.14287
Implantable photonic neural probes for light-sheet fluorescence brain imaging
2020
ABSTRACTSignificanceLight-sheet fluorescence microscopy is a powerful technique for high-speed volumetric functional imaging. However, in typical light-sheet microscopes, the illumination and collection optics impose significant constraints upon the imaging of non-transparent brain tissues. Here, we demonstrate that these constraints can be surmounted using a new class of implantable photonic neural probes.AimMass manufacturable, silicon-based light-sheet photonic neural probes can generate planar patterned illumination at arbitrary depths in brain tissues without any additional micro-optic components.ApproachWe develop implantable photonic neural probes that generate light sheets in tissue. The probes were fabricated in a photonics foundry on 200 mm diameter silicon wafers. The light sheets were characterized in fluorescein and in free space. The probe-enabled imaging approach was tested in fixed and in vitro mouse brain tissues. Imaging tests were also performed using fluorescent ...