Azure Biosystems is excited to share the first published study that uses the Azure Sapphire Biomolecular Imager! We look forward to the role the Sapphire will play in future studies. Please continue to tag us in your studies using #ImagedbyAzure- we love to read your work.
Since the release of this publication, the Azure Sapphire has been succeeded by the new Azure Sapphire FL, which was designed to be the flexible choice in bringing precise quantitation of nucleic acids and proteins. Learn more.
What’s the problem, scientifically speaking?
Labeling neurons is critical for the diagnosis, prognosis, and treatment of retinal degenerative diseases. A common approach is to use a fluorescent probe to tag anionic phosphatidylserine (PS), which cells produce early in apoptosis in order to trigger phagocytosis. Until now, the only way to tag PS was by injecting the label directly into the eye. Not only is this a painful and invasive procedure, but the injection itself can promote retinal degeneration, making this method for labeling PS undesirable for monitoring disease progression.

Technical barriers to labeling neurons
Labeling neurons is critical for the diagnosis, prognosis, and treatment of retinal degenerative diseases. A common approach is to use a fluorescent probe to tag anionic phosphatidylserine (PS), which cells produce early in apoptosis in order to trigger phagocytosis. Until now, the only way to tag PS was by injecting the label directly into the eye. Not only is this a painful and invasive procedure, but the injection itself can promote retinal degeneration, making this method for labeling PS undesirable for monitoring disease progression.
Technical barriers to labeling neurons
Until now, non-invasive PS probes have not been effective because they do not permeate the vitreous layer of the eye. Barriers in the eye make treatment of ocular disease difficult2, and previous work has focused on delivering PS probes effectively3.
What’s the solution?
Non-invasive in vivo fluorescence imaging of apoptotic retinal photoreceptors
In a study published in Scientific Reports by Mazzoni et al from Fordham University, the authors found Texas-red-conjugated PSVue-550, a commercially available probe, effectively binds to apoptotic photoreceptors when administered with an eye dropper1. Using this method, they were able to track disease progression in vivo using whole animal imaging and a retinal imaging system in both rat and mouse models of retinal degeneration.
The Sapphire Biomolecular Imager was used to confirm PSVue-550 penetration into the eye. Monitoring of disease progression is now possible in vivo using an eye dropper, replacing the need for injections.
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A step in the right direction for human retinal disease
The work by Mazzoni et al. is a significant first step toward using this method in the study and treatment of human retinal disease. The Sapphire’s superior resolution, range, and sensitivity are regularly used for important advances in disease research around the world. Check out our full list of publications to read more.
More research done with the Azure Sapphire:
Where can I learn more?
Click here to earn more about the Sapphire Biomolecular Imager and how it can enhance your research.
SOURCES
Scientific Reports 2019 Feb 7; 9(1):1590. PMID: 30733587
Pearce, W., Hsu, J., & Yeh, S. (2015). Advances in drug delivery to the posterior segment. Current opinion in ophthalmology, 26(3), 233–239.
Qiu, et al. Single-Cell Resolution Imaging of Retinal Ganglion Apoptosis In Vivo Using a Cell-Penetrating Caspase Activatable Peptide Probe. PLOS ONE 9(2), e88855.