2014 RISE Poster final
Graduate Category: Engineering and Technology Degree Level: Master’s Degree Abstract ID# 427
Abstract Axolotls salamanders, unlike humans, are capable of regenerating even complex organs such as limbs, spinal cord, and even brain (Fig. 1). The underlying mechanisms that control axolotl regeneration are still unknown. Studying how axolotls perform such feats of regeneration is important because it could facilitate future regenerative therapies.
Nanosensors for quantifying bioelectrical signaling during tissue regeneration. 1 2 2 1 Sweeney A , Balaconis MK , Clark HA , Monaghan JR
1. Department of Biology, 2. Department of Pharmaceutical Sciences, Northeastern University
Data 0hrs post injection
Aims 24hrs post injection - Test sensors ability to detect ion flux during regeneration
Conclusions
In this study, we are testing the feasibility of using novel nanosensor technologies to image biological processes in real time during one of the most extreme examples of animal regeneration, the regenerating axolotl salamander limb.
Introduction
Fig 2. Sodium-selective phere-type nanosensors (red) injected into a regenerating limb 10 days post amputation. Yellow line indicates limb outline.
Fluctuations in intracellular and extracellular ion concentrations such as sodium and potassium (bioelectricity) play many roles in biology: regulating neuron communication, cell polarity and migration, polysperm block and even development (Tseng and Levin, 2009). It has been hypothesized that bioelectricity may regulate regenerative ability (Adams et al., 2007; Borgens et al., 1977), but studying ion concentrations in animals has been technically challenging - thus a new tool is needed to observe this process in vivo. We present preliminary data suggesting that ion concentrations can be imaged and quantified during axolotl limb regeneration using novel ion-selective nanosensors.
This work demonstrates a proof of principle that nanosensor technologies are promising tools for live imaging of biological processes during complex tissue regeneration. We found that sphere-type nanosensors may be better suited for intracellular measuring of biological processes (Fig. 2), while fiber-type nanosensors are well suited for long-term extracellular measurments (Fig. 3). Lastly, a longitudinal study of nanosensor fluorescence intensity suggests a spike in sodium concentration over the first three days of regeneration (Fig. 4). Ongoing studies are being performed to optimize the delivery and imaging of nanosensors in vivo.
References Fig. 3. Fiber-type nanosensors (red) in a regenerating limb imaged at 24 hr intervals after implantation. A) 24hrs, B) 48hrs, and C)72hrs after insertion.
Tseng, A. & Levin, M. Cracking the bioelectric code: Probing endogenous ionic controls of pattern formation. Communicative & integrative biology 6, e22595, (2013). Adams, D. S., Masi, A. & Levin, M. H+ pump-dependent changes in membrane voltage are an early mechanism necessary and sufficient to induce Xenopus tail regeneration. Development 134, 1323-1335, (2007).
Fig. 1. The axolotl, Ambystoma mexicanum
Borgens, R. B., Vanable, J. W., Jr. & Jaffe, L. F. Bioelectricity and regeneration: large currents leave the stumps of regenerating newt limbs. Proc. Natl. Acad. Sci. U.S.A. 74, 4528-4532 (1977).
Acknowledgements We are grateful for the support by members of the Clark Lab for their assistance with nanosensor generation and imaging of animals. We are also greatful to members of the Monaghan lab for their help with animal care.
Fig. 4. Graph of experimental (amputated) and control (unamputated) limbs measured by fluorescence intensity over seven days. Intensities are normalized to day 0 limbs after nanofibers were implanted.
This work was supported by a Northeastern University Tier 1 grant awarded to Dr. Heather Clark and Dr. James Monaghan.
Abstract Axolotls salamanders, unlike humans, are capable of regenerating even complex organs such as limbs, spinal cord, and even brain (Fig. 1). The underlying mechanisms that control axolotl regeneration are still unknown. Studying how axolotls perform such feats of regeneration is important because it could facilitate future regenerative therapies.
Nanosensors for quantifying bioelectrical signaling during tissue regeneration. 1 2 2 1 Sweeney A , Balaconis MK , Clark HA , Monaghan JR
1. Department of Biology, 2. Department of Pharmaceutical Sciences, Northeastern University
Data 0hrs post injection
Aims 24hrs post injection - Test sensors ability to detect ion flux during regeneration
Conclusions
In this study, we are testing the feasibility of using novel nanosensor technologies to image biological processes in real time during one of the most extreme examples of animal regeneration, the regenerating axolotl salamander limb.
Introduction
Fig 2. Sodium-selective phere-type nanosensors (red) injected into a regenerating limb 10 days post amputation. Yellow line indicates limb outline.
Fluctuations in intracellular and extracellular ion concentrations such as sodium and potassium (bioelectricity) play many roles in biology: regulating neuron communication, cell polarity and migration, polysperm block and even development (Tseng and Levin, 2009). It has been hypothesized that bioelectricity may regulate regenerative ability (Adams et al., 2007; Borgens et al., 1977), but studying ion concentrations in animals has been technically challenging - thus a new tool is needed to observe this process in vivo. We present preliminary data suggesting that ion concentrations can be imaged and quantified during axolotl limb regeneration using novel ion-selective nanosensors.
This work demonstrates a proof of principle that nanosensor technologies are promising tools for live imaging of biological processes during complex tissue regeneration. We found that sphere-type nanosensors may be better suited for intracellular measuring of biological processes (Fig. 2), while fiber-type nanosensors are well suited for long-term extracellular measurments (Fig. 3). Lastly, a longitudinal study of nanosensor fluorescence intensity suggests a spike in sodium concentration over the first three days of regeneration (Fig. 4). Ongoing studies are being performed to optimize the delivery and imaging of nanosensors in vivo.
References Fig. 3. Fiber-type nanosensors (red) in a regenerating limb imaged at 24 hr intervals after implantation. A) 24hrs, B) 48hrs, and C)72hrs after insertion.
Tseng, A. & Levin, M. Cracking the bioelectric code: Probing endogenous ionic controls of pattern formation. Communicative & integrative biology 6, e22595, (2013). Adams, D. S., Masi, A. & Levin, M. H+ pump-dependent changes in membrane voltage are an early mechanism necessary and sufficient to induce Xenopus tail regeneration. Development 134, 1323-1335, (2007).
Fig. 1. The axolotl, Ambystoma mexicanum
Borgens, R. B., Vanable, J. W., Jr. & Jaffe, L. F. Bioelectricity and regeneration: large currents leave the stumps of regenerating newt limbs. Proc. Natl. Acad. Sci. U.S.A. 74, 4528-4532 (1977).
Acknowledgements We are grateful for the support by members of the Clark Lab for their assistance with nanosensor generation and imaging of animals. We are also greatful to members of the Monaghan lab for their help with animal care.
Fig. 4. Graph of experimental (amputated) and control (unamputated) limbs measured by fluorescence intensity over seven days. Intensities are normalized to day 0 limbs after nanofibers were implanted.
This work was supported by a Northeastern University Tier 1 grant awarded to Dr. Heather Clark and Dr. James Monaghan.
