Determining the Depth Limit of Bioluminescent Sources in Scattering Media

Raghuram, Ankit

doi:10.1101/2020.04.21.044982

Cited by 7 publications

(8 citation statements)

References 34 publications

(60 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As noted earlier, the blue light emission from many luciferases precludes their widespread use in some in vivo environments. Blue photons are prone to absorption by hemoglobin and other abundant chromophores in mammals (Raghuram et al, 2020;Zhao et al, 2005). CTZ is also prone to autoxidation and can be toxic to cells (Jiang et al, 2016;Shipunova et al, 2018).…”

Section: Moving Beyond the All-naturalmentioning

confidence: 99%

Seeing (and Using) the Light: Recent Developments in Bioluminescence Technology

Love

Prescher

2020

Cell Chemical Biology

View full text Add to dashboard Cite

Bioluminescence has long been used to image biological processes in vivo. This technology features luciferase enzymes and luciferin small molecules that produce visible light. Bioluminescent photons can be detected in tissues and live organisms, enabling sensitive and noninvasive readouts on physiological function. Traditional applications have focused on tracking cells and gene expression patterns, but new probes are pushing the frontiers of what can be visualized. The past few years have also seen the merger of bioluminescence with optogenetic platforms. Luciferase-luciferin reactions can drive light-activatable proteins, ultimately triggering signal transduction and other downstream events. This review highlights these and other recent advances in bioluminescence technology, with an emphasis on tool development. We showcase how new luciferins and engineered luciferases are expanding the scope of optical imaging. We also highlight how bioluminescent systems are being leveraged not just for sensing-but also controlling-biological processes. ll ll

show abstract

Section: Moving Beyond the All-naturalmentioning

confidence: 99%

Seeing (and Using) the Light: Recent Developments in Bioluminescence Technology

Love

Prescher

2020

Cell Chemical Biology

View full text Add to dashboard Cite

show abstract

“…The scattering and absorbing properties of brain tissue limit the ability of photons to travel from their point of origin unchanged 36 . Computational and empirical calculations of the mean free path (MFP) determine that for a photon of a given wavelength, the distance that photon can travel without obstruction is approximately 90 µm 37,38 . Interference accumulated as a function of distance results in scattering, limiting the ability to resolve individual sources.…”

Section: Introductionmentioning

confidence: 99%

A Method for Optimizing Imaging Parameters to Record Neuronal and Cellular Activity at Depth with Bioluminescence

Silvagnoli,

Taylor,

Slaviero

et al. 2023

Preprint

View full text Add to dashboard Cite

Optical imaging of activity has provided valuable insight into brain function and accelerated the field of neuroscience in recent years. Genetically encoded fluorescent activity sensors of calcium, neurotransmitters and voltage have been tools of choice for optical recording of neuronal activity. However, photon scattering and absorbance limits fluorescence imaging to superficial regions forin vivoactivity imaging. This limitation prevents recording of population level activity in lower brain regions of experimental animals without implanted hardware. Single and multiphoton methods find maximal use in the cortex and experience loss of signal at greater depths. Successful efforts have been made to increase the depth of fluorescence imaging using fiber photometry and gradient reflective index lenses. However, these methods are highly invasive, requiring an implant within the brain. Bioluminescence imaging offers a promising alternative to achieve activity imaging in deeper brain regions without hardware implanted within the brain. Bioluminescent reporters can be genetically encoded and produce photons without external excitation. The use of enzymatic photon production also enables prolonged imaging sessions without the risk of photobleaching or phototoxicity. These characteristics render bioluminescence suitable to non-invasive imaging of deep neuronal populations. To facilitate the adoption of bioluminescent activity imaging, we sought to develop a low cost, simplein vitromethod to optimize imaging parameters for determining optimal exposure times and optical hardware configurations to determine what frame rates can be captured with an individual lab’s imaging hardware with sufficient signal-to-noise ratios without the use of animals prior to starting anin vivoexperiment. To achieve this, we developed an assay for modelingin vivooptical conditions with a brain tissue phantom paired with engineered cells that produce bioluminescence. We then used this assay to limit-test the detection depth vs maximum frame rate for bioluminescence imaging at experimentally relevant tissue depths using off the shelf imaging hardware. With this method, we demonstrate an effective means for increasing the utility of bioluminescent tools and lowering the barrier to adoption of bioluminescence activity imaging with bioluminescent sensors.

show abstract

“…Imaging depths were determined from. 5 The estimated increase in imaging depth is especially beneficial for spinal cord imaging because it is significantly constrained by photon scattering properties of myelin. The brain background image in (b) is from 6 and is in the public domain, the spinal cord image in (b) is from, 7 licensed under Public Domain Mark 1.0. understanding these complex interdependencies also requires simultaneously recording biological activity across multiple organs.…”

Section: Introductionmentioning

confidence: 99%

Towards a Brighter Constellation: Multi-Organ Neuroimaging of Neural and Vascular Dynamics in the Spinal Cord and Brain

Celinskis,

Black,

Murphy

et al. 2023

Preprint

View full text Add to dashboard Cite

SignificancePain is comprised of a complex interaction between motor action and somatosensation that is dependent on dynamic interactions between the brain and spinal cord. This makes understanding pain particularly challenging as it involves rich interactions between many circuits (e.g., neural and vascular) and signaling cascades throughout the body. As such, experimentation on a single region may lead to an incomplete and potentially incorrect understanding of crucial underlying mechanisms.AimHere, we aimed to develop and validate new tools to enable detailed and extended observation of neural and vascular activity in the brain and spinal cord. The first key set of innovations were targeted to developing novel imaging hardware that addresses the many challenges of multi-site imaging. The second key set of innovations were targeted to enabling bioluminescent imaging, as this approach can address limitations of fluorescent microscopy including photobleaching, phototoxicity and decreased resolution due to scattering of excitation signals.ApproachWe designed 3D-printed brain and spinal cord implants to enable effective surgical implantations and optical access with wearable miniscopes or an open window (e.g., for one-or two-photon microscopy or optogenetic stimulation). We also tested the viability for bioluminescent imaging, and developed a novel modified miniscope optimized for these signals (BLmini).ResultsHere, we describe novel ‘universal’ implants for acute and chronic simultaneous brain-spinal cord imaging and optical stimulation. We further describe successful imaging of bioluminescent signals in both foci, and a new miniscope, the ‘BLmini,’ which has reduced weight, cost and form-factor relative to standard wearable miniscopes.ConclusionsThe combination of 3D printed implants, advanced imaging tools, and bioluminescence imaging techniques offers a new coalition of methods for understanding spinal cord-brain interactions. This work has the potential for use in future research into neuropathic pain and other sensory disorders and motor behavior.

show abstract

Determining the Depth Limit of Bioluminescent Sources in Scattering Media

Cited by 7 publications

References 34 publications

Seeing (and Using) the Light: Recent Developments in Bioluminescence Technology

Seeing (and Using) the Light: Recent Developments in Bioluminescence Technology

A Method for Optimizing Imaging Parameters to Record Neuronal and Cellular Activity at Depth with Bioluminescence

Towards a Brighter Constellation: Multi-Organ Neuroimaging of Neural and Vascular Dynamics in the Spinal Cord and Brain

Contact Info

Product

Resources

About