Abstract

Laser scanners are an integral part of high resolution biomedical imaging systems such as confocal or 2-photon excitation (2PE) microscopes. In this work, we demonstrate the utility of electrowetting on dielectric (EWOD) prisms as a lateral laser-scanning element integrated in a conventional 2PE microscope. To the best of our knowledge, this is the first such demonstration for EWOD prisms. EWOD devices provide a transmissive, low power consuming, and compact alternative to conventional adaptive optics, and hence this technology has tremendous potential. We demonstrate 2PE microscope imaging of cultured mouse hippocampal neurons with a FOV of 130 × 130 μm2 using EWOD prism scanning. In addition, we show simulations of the optical system with the EWOD prism, to evaluate the effect of propagating a Gaussian beam through the EWOD prism on the imaging quality. Based on the simulation results a beam size of 0.91 mm full width half max was chosen to conduct the imaging experiments, resulting in a numerical aperture of 0.17 of the imaging system.

© 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

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References

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2017 (5)

S. R. Schultz, C. S. Copeland, A. J. Foust, P. Quicke, and R. Schuck, “Advances in two photon scanning and scanless microscopy technologies for functional neural circuit imaging,” Proc. IEEE Inst. Electr. Electron. Eng. 105(1), 139–157 (2017).
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W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

W. Yang and R. Yuste, “In vivo imaging of neural activity,” Nat. Methods 14(4), 349–359 (2017).
[PubMed]

A. Shahini, H. Jin, Z. Zhou, Y. Zhao, P. Y. Chen, J. Hua, and M. M. Cheng, “Toward individually tunable compound eyes with transparent graphene electrode,” Bioinspir. Biomim. 12(4), 046002 (2017).
[PubMed]

O. D. Supekar, M. Zohrabi, J. T. Gopinath, and V. M. Bright, “Enhanced response time of electrowetting lenses with shaped input voltage functions,” Langmuir 33(19), 4863–4869 (2017).
[PubMed]

2016 (3)

2015 (3)

2013 (2)

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

F. Helmchen, W. Denk, and J. N. D. Kerr, “Miniaturization of two-photon microscopy for imaging in freely moving animals,” Cold Spring Harb. Protoc. 2013(10), 904–913 (2013).
[PubMed]

2010 (1)

S. Preibisch, S. Saalfeld, J. Schindelin, and P. Tomancak, “Software for bead-based registration of selective plane illumination microscopy data,” Nat. Methods 7(6), 418–419 (2010).
[PubMed]

2009 (2)

S. Murali, K. P. Thompson, and J. P. Rolland, “Three-dimensional adaptive microscopy using embedded liquid lens,” Opt. Lett. 34(2), 145–147 (2009).
[PubMed]

J. Sawinski, D. J. Wallace, D. S. Greenberg, S. Grossmann, W. Denk, and J. N. D. Kerr, “Visually evoked activity in cortical cells imaged in freely moving animals,” Proc. Natl. Acad. Sci. U.S.A. 106(46), 19557–19562 (2009).
[PubMed]

2007 (2)

W. C. Warger and C. A. DiMarzio, “Dual-wedge scanning confocal reflectance microscope,” Opt. Lett. 32(15), 2140–2142 (2007).
[PubMed]

A. Takei, E. Iwase, K. Hoshino, K. Matsumoto, and I. Shimoyama, “Angle-tunable liquid wedge prism driven by electrowetting,” J. Microelectromech. Syst. 16, 1537–1542 (2007).

2006 (4)

N. R. Smith, D. C. Abeysinghe, J. W. Haus, and J. Heikenfeld, “Agile wide-angle beam steering with electrowetting microprisms,” Opt. Express 14(14), 6557–6563 (2006).
[PubMed]

R. Salomé, Y. Kremer, S. Dieudonné, J. F. Léger, O. Krichevsky, C. Wyart, D. Chatenay, and L. Bourdieu, “Ultrafast random-access scanning in two-photon microscopy using acousto-optic deflectors,” J. Neurosci. Methods 154(1-2), 161–174 (2006).
[PubMed]

K. Svoboda and R. Yasuda, “Principles of two-photon excitation microscopy and its applications to neuroscience,” Neuron 50(6), 823–839 (2006).
[PubMed]

M. T. Myaing, D. J. MacDonald, and X. Li, “Fiber-optic scanning two-photon fluorescence endoscope,” Opt. Lett. 31(8), 1076–1078 (2006).
[PubMed]

2005 (2)

F. Helmchen and W. Denk, “Deep tissue two-photon microscopy,” Nat. Methods 2(12), 932–940 (2005).
[PubMed]

F. Mugele and J.-C. Baret, “Electrowetting: from basics to applications,” J. Phys. Condens. Matter 17, R705–R774 (2005).

2004 (2)

2003 (1)

2002 (1)

F. Helmchen, “Miniaturization of fluorescence microscopes using fibre optics,” Exp. Physiol. 87(6), 737–745 (2002).
[PubMed]

2001 (1)

F. Helmchen, M. S. Fee, D. W. Tank, and W. Denk, “A miniature head-mounted two-photon microscope. high-resolution brain imaging in freely moving animals,” Neuron 31(6), 903–912 (2001).
[PubMed]

2000 (1)

B. Berge and J. Peseux, “Variable focal lens controlled by an external voltage: An application of electrowetting,” Eur. Phys. J. E 3, 159–163 (2000).

1990 (1)

W. Denk, J. H. Strickler, and W. W. Webb, “Two-photon laser scanning fluorescence microscopy,” Science 248(4951), 73–76 (1990).
[PubMed]

Abeysinghe, D. C.

Aponte, Y.

Baohan, A.

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

Baret, J.-C.

F. Mugele and J.-C. Baret, “Electrowetting: from basics to applications,” J. Phys. Condens. Matter 17, R705–R774 (2005).

Berge, B.

B. Berge and J. Peseux, “Variable focal lens controlled by an external voltage: An application of electrowetting,” Eur. Phys. J. E 3, 159–163 (2000).

Bird, D.

Bocarsly, M. E.

Bourdieu, L.

R. Salomé, Y. Kremer, S. Dieudonné, J. F. Léger, O. Krichevsky, C. Wyart, D. Chatenay, and L. Bourdieu, “Ultrafast random-access scanning in two-photon microscopy using acousto-optic deflectors,” J. Neurosci. Methods 154(1-2), 161–174 (2006).
[PubMed]

Bright, V. M.

Chatenay, D.

R. Salomé, Y. Kremer, S. Dieudonné, J. F. Léger, O. Krichevsky, C. Wyart, D. Chatenay, and L. Bourdieu, “Ultrafast random-access scanning in two-photon microscopy using acousto-optic deflectors,” J. Neurosci. Methods 154(1-2), 161–174 (2006).
[PubMed]

Chen, L.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Chen, P. Y.

A. Shahini, H. Jin, Z. Zhou, Y. Zhao, P. Y. Chen, J. Hua, and M. M. Cheng, “Toward individually tunable compound eyes with transparent graphene electrode,” Bioinspir. Biomim. 12(4), 046002 (2017).
[PubMed]

Chen, T.-W.

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

Cheng, H.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Cheng, M. M.

A. Shahini, H. Jin, Z. Zhou, Y. Zhao, P. Y. Chen, J. Hua, and M. M. Cheng, “Toward individually tunable compound eyes with transparent graphene electrode,” Bioinspir. Biomim. 12(4), 046002 (2017).
[PubMed]

Cheng, M. M. C.

A. Shahini, J. Xia, Z. Zhou, Y. Zhao, and M. M. C. Cheng, “Versatile miniature tunable liquid lenses using transparent graphene electrodes,” Langmuir 32(6), 1658–1665 (2016).
[PubMed]

Copeland, C. S.

S. R. Schultz, C. S. Copeland, A. J. Foust, P. Quicke, and R. Schuck, “Advances in two photon scanning and scanless microscopy technologies for functional neural circuit imaging,” Proc. IEEE Inst. Electr. Electron. Eng. 105(1), 139–157 (2017).
[PubMed]

Cormack, R.

Cormack, R. H.

Denk, W.

F. Helmchen, W. Denk, and J. N. D. Kerr, “Miniaturization of two-photon microscopy for imaging in freely moving animals,” Cold Spring Harb. Protoc. 2013(10), 904–913 (2013).
[PubMed]

J. Sawinski, D. J. Wallace, D. S. Greenberg, S. Grossmann, W. Denk, and J. N. D. Kerr, “Visually evoked activity in cortical cells imaged in freely moving animals,” Proc. Natl. Acad. Sci. U.S.A. 106(46), 19557–19562 (2009).
[PubMed]

F. Helmchen and W. Denk, “Deep tissue two-photon microscopy,” Nat. Methods 2(12), 932–940 (2005).
[PubMed]

F. Helmchen, M. S. Fee, D. W. Tank, and W. Denk, “A miniature head-mounted two-photon microscope. high-resolution brain imaging in freely moving animals,” Neuron 31(6), 903–912 (2001).
[PubMed]

W. Denk, J. H. Strickler, and W. W. Webb, “Two-photon laser scanning fluorescence microscopy,” Science 248(4951), 73–76 (1990).
[PubMed]

Dieudonné, S.

R. Salomé, Y. Kremer, S. Dieudonné, J. F. Léger, O. Krichevsky, C. Wyart, D. Chatenay, and L. Bourdieu, “Ultrafast random-access scanning in two-photon microscopy using acousto-optic deflectors,” J. Neurosci. Methods 154(1-2), 161–174 (2006).
[PubMed]

DiMarzio, C. A.

Dudman, J. T.

Fan, M.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Fee, M. S.

F. Helmchen, M. S. Fee, D. W. Tank, and W. Denk, “A miniature head-mounted two-photon microscope. high-resolution brain imaging in freely moving animals,” Neuron 31(6), 903–912 (2001).
[PubMed]

Foust, A. J.

S. R. Schultz, C. S. Copeland, A. J. Foust, P. Quicke, and R. Schuck, “Advances in two photon scanning and scanless microscopy technologies for functional neural circuit imaging,” Proc. IEEE Inst. Electr. Electron. Eng. 105(1), 139–157 (2017).
[PubMed]

Gibson, E. A.

Göbel, W.

Gopinath, J. T.

Greenberg, D. S.

J. Sawinski, D. J. Wallace, D. S. Greenberg, S. Grossmann, W. Denk, and J. N. D. Kerr, “Visually evoked activity in cortical cells imaged in freely moving animals,” Proc. Natl. Acad. Sci. U.S.A. 106(46), 19557–19562 (2009).
[PubMed]

Grossmann, S.

J. Sawinski, D. J. Wallace, D. S. Greenberg, S. Grossmann, W. Denk, and J. N. D. Kerr, “Visually evoked activity in cortical cells imaged in freely moving animals,” Proc. Natl. Acad. Sci. U.S.A. 106(46), 19557–19562 (2009).
[PubMed]

Gu, M.

Haus, J. W.

Heikenfeld, J.

Helmchen, F.

F. Helmchen, W. Denk, and J. N. D. Kerr, “Miniaturization of two-photon microscopy for imaging in freely moving animals,” Cold Spring Harb. Protoc. 2013(10), 904–913 (2013).
[PubMed]

F. Helmchen and W. Denk, “Deep tissue two-photon microscopy,” Nat. Methods 2(12), 932–940 (2005).
[PubMed]

W. Göbel, J. N. D. Kerr, A. Nimmerjahn, and F. Helmchen, “Miniaturized two-photon microscope based on a flexible coherent fiber bundle and a gradient-index lens objective,” Opt. Lett. 29(21), 2521–2523 (2004).
[PubMed]

F. Helmchen, “Miniaturization of fluorescence microscopes using fibre optics,” Exp. Physiol. 87(6), 737–745 (2002).
[PubMed]

F. Helmchen, M. S. Fee, D. W. Tank, and W. Denk, “A miniature head-mounted two-photon microscope. high-resolution brain imaging in freely moving animals,” Neuron 31(6), 903–912 (2001).
[PubMed]

Hendriks, B. H. W.

S. Kuiper and B. H. W. Hendriks, “Variable-focus liquid lens for miniature cameras,” Appl. Phys. Lett. 85, 1128–1130 (2004).

Hoshino, K.

A. Takei, E. Iwase, K. Hoshino, K. Matsumoto, and I. Shimoyama, “Angle-tunable liquid wedge prism driven by electrowetting,” J. Microelectromech. Syst. 16, 1537–1542 (2007).

Hu, Y.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Hua, J.

A. Shahini, H. Jin, Z. Zhou, Y. Zhao, P. Y. Chen, J. Hua, and M. M. Cheng, “Toward individually tunable compound eyes with transparent graphene electrode,” Bioinspir. Biomim. 12(4), 046002 (2017).
[PubMed]

Iwase, E.

A. Takei, E. Iwase, K. Hoshino, K. Matsumoto, and I. Shimoyama, “Angle-tunable liquid wedge prism driven by electrowetting,” J. Microelectromech. Syst. 16, 1537–1542 (2007).

Jayaraman, V.

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

Ji, N.

Jia, H.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Jiang, W. C.

Jin, H.

A. Shahini, H. Jin, Z. Zhou, Y. Zhao, P. Y. Chen, J. Hua, and M. M. Cheng, “Toward individually tunable compound eyes with transparent graphene electrode,” Bioinspir. Biomim. 12(4), 046002 (2017).
[PubMed]

Kerr, J. N. D.

F. Helmchen, W. Denk, and J. N. D. Kerr, “Miniaturization of two-photon microscopy for imaging in freely moving animals,” Cold Spring Harb. Protoc. 2013(10), 904–913 (2013).
[PubMed]

J. Sawinski, D. J. Wallace, D. S. Greenberg, S. Grossmann, W. Denk, and J. N. D. Kerr, “Visually evoked activity in cortical cells imaged in freely moving animals,” Proc. Natl. Acad. Sci. U.S.A. 106(46), 19557–19562 (2009).
[PubMed]

W. Göbel, J. N. D. Kerr, A. Nimmerjahn, and F. Helmchen, “Miniaturized two-photon microscope based on a flexible coherent fiber bundle and a gradient-index lens objective,” Opt. Lett. 29(21), 2521–2523 (2004).
[PubMed]

Kerr, R. A.

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

Kim, D. S.

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

Kopp, D.

Kremer, Y.

R. Salomé, Y. Kremer, S. Dieudonné, J. F. Léger, O. Krichevsky, C. Wyart, D. Chatenay, and L. Bourdieu, “Ultrafast random-access scanning in two-photon microscopy using acousto-optic deflectors,” J. Neurosci. Methods 154(1-2), 161–174 (2006).
[PubMed]

Krichevsky, O.

R. Salomé, Y. Kremer, S. Dieudonné, J. F. Léger, O. Krichevsky, C. Wyart, D. Chatenay, and L. Bourdieu, “Ultrafast random-access scanning in two-photon microscopy using acousto-optic deflectors,” J. Neurosci. Methods 154(1-2), 161–174 (2006).
[PubMed]

Kuiper, S.

S. Kuiper and B. H. W. Hendriks, “Variable-focus liquid lens for miniature cameras,” Appl. Phys. Lett. 85, 1128–1130 (2004).

Léger, J. F.

R. Salomé, Y. Kremer, S. Dieudonné, J. F. Léger, O. Krichevsky, C. Wyart, D. Chatenay, and L. Bourdieu, “Ultrafast random-access scanning in two-photon microscopy using acousto-optic deflectors,” J. Neurosci. Methods 154(1-2), 161–174 (2006).
[PubMed]

Lehmann, L.

Li, J.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Li, M.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Li, X.

Li, Y.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Looger, L. L.

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

Losacco, J. T.

Lu, Y.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

MacDonald, D. J.

Matsumoto, K.

A. Takei, E. Iwase, K. Hoshino, K. Matsumoto, and I. Shimoyama, “Angle-tunable liquid wedge prism driven by electrowetting,” J. Microelectromech. Syst. 16, 1537–1542 (2007).

Mugele, F.

F. Mugele and J.-C. Baret, “Electrowetting: from basics to applications,” J. Phys. Condens. Matter 17, R705–R774 (2005).

Murali, S.

Myaing, M. T.

Nimmerjahn, A.

Orger, M. B.

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

Ozbay, B. N.

Peseux, J.

B. Berge and J. Peseux, “Variable focal lens controlled by an external voltage: An application of electrowetting,” Eur. Phys. J. E 3, 159–163 (2000).

Preibisch, S.

S. Preibisch, S. Saalfeld, J. Schindelin, and P. Tomancak, “Software for bead-based registration of selective plane illumination microscopy data,” Nat. Methods 7(6), 418–419 (2010).
[PubMed]

Pulver, S. R.

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

Quicke, P.

S. R. Schultz, C. S. Copeland, A. J. Foust, P. Quicke, and R. Schuck, “Advances in two photon scanning and scanless microscopy technologies for functional neural circuit imaging,” Proc. IEEE Inst. Electr. Electron. Eng. 105(1), 139–157 (2017).
[PubMed]

Renninger, S. L.

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

Restrepo, D.

Roath, C.

Rolland, J. P.

Rong, H.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Saalfeld, S.

S. Preibisch, S. Saalfeld, J. Schindelin, and P. Tomancak, “Software for bead-based registration of selective plane illumination microscopy data,” Nat. Methods 7(6), 418–419 (2010).
[PubMed]

Salomé, R.

R. Salomé, Y. Kremer, S. Dieudonné, J. F. Léger, O. Krichevsky, C. Wyart, D. Chatenay, and L. Bourdieu, “Ultrafast random-access scanning in two-photon microscopy using acousto-optic deflectors,” J. Neurosci. Methods 154(1-2), 161–174 (2006).
[PubMed]

Sawinski, J.

J. Sawinski, D. J. Wallace, D. S. Greenberg, S. Grossmann, W. Denk, and J. N. D. Kerr, “Visually evoked activity in cortical cells imaged in freely moving animals,” Proc. Natl. Acad. Sci. U.S.A. 106(46), 19557–19562 (2009).
[PubMed]

Schindelin, J.

S. Preibisch, S. Saalfeld, J. Schindelin, and P. Tomancak, “Software for bead-based registration of selective plane illumination microscopy data,” Nat. Methods 7(6), 418–419 (2010).
[PubMed]

Schreiter, E. R.

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

Schuck, R.

S. R. Schultz, C. S. Copeland, A. J. Foust, P. Quicke, and R. Schuck, “Advances in two photon scanning and scanless microscopy technologies for functional neural circuit imaging,” Proc. IEEE Inst. Electr. Electron. Eng. 105(1), 139–157 (2017).
[PubMed]

Schultz, S. R.

S. R. Schultz, C. S. Copeland, A. J. Foust, P. Quicke, and R. Schuck, “Advances in two photon scanning and scanless microscopy technologies for functional neural circuit imaging,” Proc. IEEE Inst. Electr. Electron. Eng. 105(1), 139–157 (2017).
[PubMed]

Shahini, A.

A. Shahini, H. Jin, Z. Zhou, Y. Zhao, P. Y. Chen, J. Hua, and M. M. Cheng, “Toward individually tunable compound eyes with transparent graphene electrode,” Bioinspir. Biomim. 12(4), 046002 (2017).
[PubMed]

A. Shahini, J. Xia, Z. Zhou, Y. Zhao, and M. M. C. Cheng, “Versatile miniature tunable liquid lenses using transparent graphene electrodes,” Langmuir 32(6), 1658–1665 (2016).
[PubMed]

Shimoyama, I.

A. Takei, E. Iwase, K. Hoshino, K. Matsumoto, and I. Shimoyama, “Angle-tunable liquid wedge prism driven by electrowetting,” J. Microelectromech. Syst. 16, 1537–1542 (2007).

Smith, N. R.

Strickler, J. H.

W. Denk, J. H. Strickler, and W. W. Webb, “Two-photon laser scanning fluorescence microscopy,” Science 248(4951), 73–76 (1990).
[PubMed]

Sun, Y.

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

Supekar, O. D.

O. D. Supekar, M. Zohrabi, J. T. Gopinath, and V. M. Bright, “Enhanced response time of electrowetting lenses with shaped input voltage functions,” Langmuir 33(19), 4863–4869 (2017).
[PubMed]

Svoboda, K.

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

K. Svoboda and R. Yasuda, “Principles of two-photon excitation microscopy and its applications to neuroscience,” Neuron 50(6), 823–839 (2006).
[PubMed]

Takei, A.

A. Takei, E. Iwase, K. Hoshino, K. Matsumoto, and I. Shimoyama, “Angle-tunable liquid wedge prism driven by electrowetting,” J. Microelectromech. Syst. 16, 1537–1542 (2007).

Tank, D. W.

F. Helmchen, M. S. Fee, D. W. Tank, and W. Denk, “A miniature head-mounted two-photon microscope. high-resolution brain imaging in freely moving animals,” Neuron 31(6), 903–912 (2001).
[PubMed]

Terrab, S.

Thompson, K. P.

Tomancak, P.

S. Preibisch, S. Saalfeld, J. Schindelin, and P. Tomancak, “Software for bead-based registration of selective plane illumination microscopy data,” Nat. Methods 7(6), 418–419 (2010).
[PubMed]

Wallace, D. J.

J. Sawinski, D. J. Wallace, D. S. Greenberg, S. Grossmann, W. Denk, and J. N. D. Kerr, “Visually evoked activity in cortical cells imaged in freely moving animals,” Proc. Natl. Acad. Sci. U.S.A. 106(46), 19557–19562 (2009).
[PubMed]

Wang, A.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Wang, C.

Wardill, T. J.

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

Warger, W. C.

Watson, A. M.

Webb, W. W.

W. Denk, J. H. Strickler, and W. W. Webb, “Two-photon laser scanning fluorescence microscopy,” Science 248(4951), 73–76 (1990).
[PubMed]

Weir, R.

Wu, H.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Wu, R.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Wyart, C.

R. Salomé, Y. Kremer, S. Dieudonné, J. F. Léger, O. Krichevsky, C. Wyart, D. Chatenay, and L. Bourdieu, “Ultrafast random-access scanning in two-photon microscopy using acousto-optic deflectors,” J. Neurosci. Methods 154(1-2), 161–174 (2006).
[PubMed]

Xia, J.

A. Shahini, J. Xia, Z. Zhou, Y. Zhao, and M. M. C. Cheng, “Versatile miniature tunable liquid lenses using transparent graphene electrodes,” Langmuir 32(6), 1658–1665 (2016).
[PubMed]

Xu, Y.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Yang, W.

W. Yang and R. Yuste, “In vivo imaging of neural activity,” Nat. Methods 14(4), 349–359 (2017).
[PubMed]

Yasuda, R.

K. Svoboda and R. Yasuda, “Principles of two-photon excitation microscopy and its applications to neuroscience,” Neuron 50(6), 823–839 (2006).
[PubMed]

Yuste, R.

W. Yang and R. Yuste, “In vivo imaging of neural activity,” Nat. Methods 14(4), 349–359 (2017).
[PubMed]

Zappe, H.

Zhang, Y.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Zhao, Y.

A. Shahini, H. Jin, Z. Zhou, Y. Zhao, P. Y. Chen, J. Hua, and M. M. Cheng, “Toward individually tunable compound eyes with transparent graphene electrode,” Bioinspir. Biomim. 12(4), 046002 (2017).
[PubMed]

A. Shahini, J. Xia, Z. Zhou, Y. Zhao, and M. M. C. Cheng, “Versatile miniature tunable liquid lenses using transparent graphene electrodes,” Langmuir 32(6), 1658–1665 (2016).
[PubMed]

Zhou, Z.

A. Shahini, H. Jin, Z. Zhou, Y. Zhao, P. Y. Chen, J. Hua, and M. M. Cheng, “Toward individually tunable compound eyes with transparent graphene electrode,” Bioinspir. Biomim. 12(4), 046002 (2017).
[PubMed]

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

A. Shahini, J. Xia, Z. Zhou, Y. Zhao, and M. M. C. Cheng, “Versatile miniature tunable liquid lenses using transparent graphene electrodes,” Langmuir 32(6), 1658–1665 (2016).
[PubMed]

Zohrabi, M.

O. D. Supekar, M. Zohrabi, J. T. Gopinath, and V. M. Bright, “Enhanced response time of electrowetting lenses with shaped input voltage functions,” Langmuir 33(19), 4863–4869 (2017).
[PubMed]

M. Zohrabi, R. H. Cormack, and J. T. Gopinath, “Wide-angle nonmechanical beam steering using liquid lenses,” Opt. Express 24(21), 23798–23809 (2016).
[PubMed]

Zong, W.

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

Appl. Opt. (1)

Appl. Phys. Lett. (1)

S. Kuiper and B. H. W. Hendriks, “Variable-focus liquid lens for miniature cameras,” Appl. Phys. Lett. 85, 1128–1130 (2004).

Bioinspir. Biomim. (1)

A. Shahini, H. Jin, Z. Zhou, Y. Zhao, P. Y. Chen, J. Hua, and M. M. Cheng, “Toward individually tunable compound eyes with transparent graphene electrode,” Bioinspir. Biomim. 12(4), 046002 (2017).
[PubMed]

Biomed. Opt. Express (1)

Cold Spring Harb. Protoc. (1)

F. Helmchen, W. Denk, and J. N. D. Kerr, “Miniaturization of two-photon microscopy for imaging in freely moving animals,” Cold Spring Harb. Protoc. 2013(10), 904–913 (2013).
[PubMed]

Eur. Phys. J. E (1)

B. Berge and J. Peseux, “Variable focal lens controlled by an external voltage: An application of electrowetting,” Eur. Phys. J. E 3, 159–163 (2000).

Exp. Physiol. (1)

F. Helmchen, “Miniaturization of fluorescence microscopes using fibre optics,” Exp. Physiol. 87(6), 737–745 (2002).
[PubMed]

J. Microelectromech. Syst. (1)

A. Takei, E. Iwase, K. Hoshino, K. Matsumoto, and I. Shimoyama, “Angle-tunable liquid wedge prism driven by electrowetting,” J. Microelectromech. Syst. 16, 1537–1542 (2007).

J. Neurosci. Methods (1)

R. Salomé, Y. Kremer, S. Dieudonné, J. F. Léger, O. Krichevsky, C. Wyart, D. Chatenay, and L. Bourdieu, “Ultrafast random-access scanning in two-photon microscopy using acousto-optic deflectors,” J. Neurosci. Methods 154(1-2), 161–174 (2006).
[PubMed]

J. Phys. Condens. Matter (1)

F. Mugele and J.-C. Baret, “Electrowetting: from basics to applications,” J. Phys. Condens. Matter 17, R705–R774 (2005).

Langmuir (2)

A. Shahini, J. Xia, Z. Zhou, Y. Zhao, and M. M. C. Cheng, “Versatile miniature tunable liquid lenses using transparent graphene electrodes,” Langmuir 32(6), 1658–1665 (2016).
[PubMed]

O. D. Supekar, M. Zohrabi, J. T. Gopinath, and V. M. Bright, “Enhanced response time of electrowetting lenses with shaped input voltage functions,” Langmuir 33(19), 4863–4869 (2017).
[PubMed]

Nat. Methods (4)

S. Preibisch, S. Saalfeld, J. Schindelin, and P. Tomancak, “Software for bead-based registration of selective plane illumination microscopy data,” Nat. Methods 7(6), 418–419 (2010).
[PubMed]

W. Zong, R. Wu, M. Li, Y. Hu, Y. Li, J. Li, H. Rong, H. Wu, Y. Xu, Y. Lu, H. Jia, M. Fan, Z. Zhou, Y. Zhang, A. Wang, L. Chen, and H. Cheng, “Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice,” Nat. Methods 14(7), 713–719 (2017).
[PubMed]

W. Yang and R. Yuste, “In vivo imaging of neural activity,” Nat. Methods 14(4), 349–359 (2017).
[PubMed]

F. Helmchen and W. Denk, “Deep tissue two-photon microscopy,” Nat. Methods 2(12), 932–940 (2005).
[PubMed]

Nature (1)

T.-W. Chen, T. J. Wardill, Y. Sun, S. R. Pulver, S. L. Renninger, A. Baohan, E. R. Schreiter, R. A. Kerr, M. B. Orger, V. Jayaraman, L. L. Looger, K. Svoboda, and D. S. Kim, “Ultrasensitive fluorescent proteins for imaging neuronal activity,” Nature 499(7458), 295–300 (2013).
[PubMed]

Neuron (2)

F. Helmchen, M. S. Fee, D. W. Tank, and W. Denk, “A miniature head-mounted two-photon microscope. high-resolution brain imaging in freely moving animals,” Neuron 31(6), 903–912 (2001).
[PubMed]

K. Svoboda and R. Yasuda, “Principles of two-photon excitation microscopy and its applications to neuroscience,” Neuron 50(6), 823–839 (2006).
[PubMed]

Opt. Express (3)

Opt. Lett. (6)

Proc. IEEE Inst. Electr. Electron. Eng. (1)

S. R. Schultz, C. S. Copeland, A. J. Foust, P. Quicke, and R. Schuck, “Advances in two photon scanning and scanless microscopy technologies for functional neural circuit imaging,” Proc. IEEE Inst. Electr. Electron. Eng. 105(1), 139–157 (2017).
[PubMed]

Proc. Natl. Acad. Sci. U.S.A. (1)

J. Sawinski, D. J. Wallace, D. S. Greenberg, S. Grossmann, W. Denk, and J. N. D. Kerr, “Visually evoked activity in cortical cells imaged in freely moving animals,” Proc. Natl. Acad. Sci. U.S.A. 106(46), 19557–19562 (2009).
[PubMed]

Science (1)

W. Denk, J. H. Strickler, and W. W. Webb, “Two-photon laser scanning fluorescence microscopy,” Science 248(4951), 73–76 (1990).
[PubMed]

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Figures (9)

Fig. 1
Fig. 1 Device fabrication, packaging and operation. (a) Schematic of the device with components labeled. An optical window with patterned Ti/Au/Ti layer serves as the ground electrode. The device is constructed in a cylindrical glass tube with ITO sidewall electrodes, Parylene HT as the dielectric and Teflon as the hydrophobic layer. (b) An image of the device bonded to the custom 3D printed mount, with liquids filled and capped with an optical window. (c) Demonstration of the device functioning as a tunable prism, (center) device functioning as a diverging lens with no applied voltage, (left) 35 V applied to the left sidewall, and (right) 35 V applied to the right sidewall. Ti/Au/Ti = Titanium/Gold/Titanium; ITO = Indium Tin Oxide.
Fig. 2
Fig. 2 Schematic of the imaging setup. A mode-locked Ti:Sapphire laser (Spectra-Physics, Mai Tai HP DeepSee) at an output wavelength of 950 nm is used as the excitation source. The reverse beam expander is used to reduce the beam size to 0.91 mm FWHM. Lens 1 (L1) focal length = 75 mm. Lens 2 (L2) focal length = −40 mm. A commercially available EWOD lens (EWL) (Arctic 316) is placed right before the EWOD prism to compensate for the focal length change during EWOD prism (EWP) actuation. The green beam indicates the scanned beam from the EWOD prism upon actuation. Relay lenses are used to relay the scan angle from the EWOD prism onto the galvo mirror plane. Relay lens 1 (RL1) and 2 (RL2) focal length = 125 mm. The microscope Olympus IX71 body contains a scan lens (SL), focal length = 50 mm, and tube lens (TL), focal length = 180 mm, system required for lateral scanning through the objective (Olympus 20X/0.75 UPlanSApo). FWHM = Full width half max.
Fig. 3
Fig. 3 Schematic of the simulation setup. EWOD lens, followed by the EWOD prism. The green beam indicates the scanned beam from the EWOD prism upon actuation. In the simulation setup, the galvo scanner and relay lenses are removed. The scan lens, tube lens, and the objective are replaced by paraxial lenses with the same focal length. EWOD = Electrowetting on dielectric.
Fig. 4
Fig. 4 (a) EWOD prism scanning as a function of applied voltage. It is evident that the scanning is very consistent on both the directions and repeatable. (b) Beam spot position on camera for all actuating voltages, the scan follows a straight line fit with an R-squared value of 0.998; The error bars indicate the standard deviation of the experimental results. EWOD = Electrowetting on dielectric.
Fig. 5
Fig. 5 (a) Zemax diagram of multi-configuration model of EWOD tunable focus lens (Varioptic Arctic 316) and EWOD prism showing three surface models of EWOD prism actuation at 0V, 20V, and 35V. Rays shown have a diameter of 0.91 mm FWHM. (b, c) Change in focal length setting on EWOD lens required to maintain the highest peak irradiance at the Gaussian focus after the objective lens, plotted as a function of EWOD actuation voltage (b) and EWOD scan actuation angle (c). EWOD = Electrowetting on dielectric, FWHM = Full width half max.
Fig. 6
Fig. 6 (a) Lateral profiles of Gaussian beam foci, simulated in Zemax, as a function of increasing EWOD prism actuation voltage. The larger input beam (red-dashed, 1.43 mm FWHM) results in higher peak irradiance at low scan angles, while degrading faster than the smaller input beam (black-dashed, 0.91 mm FWHM) at higher EWOD prism voltages. (b) Transverse profiles of the simulated beam foci across voltage range. At larger scan angles, the beams are heavily aberrated in the EWOD prism scanning axis, resulting in reduced peak irradiance. Scale bar is 40 µm. (c) Focus-spot NA and power transmission through the Zemax model as a function of input beam size. EWOD prism is set to 0V. Beam sizes used in (a) and (b) are marked. The large beam size required to reduce power transmission suggests that optical aberrations, not clipping, is the main cause of the flattening of the NA increase curve. EWOD = Electrowetting on dielectric.
Fig. 7
Fig. 7 (a) Image of the grid target acquired using galvo scanners, the grid spacing in the target is 7.5μm. (b) Image of the grid target acquired using EWOD prism raster scanning, the distortions are a result of non-linearity in the scan. (c) Actuation function used to drive the EWOD prism, the function shown in Eq. (2) is alternately applied to both electrodes.
Fig. 8
Fig. 8 (a) Image of the grid target acquired using galvo scanners, the grid spacing in the target is 7.5μm. (b) Image of the grid target acquired using EWOD prism raster scanning after distortion correction. The warping in the image is corrected by vector field mapping using a shape preserving spline interpolant function.
Fig. 9
Fig. 9 (a) Image of a neuron collected using galvo scanners. (b) Image of the same neuron collected using EWOD prism scanning, the dotted box indicates the region of interest for image intensity plot (d). (c) Image (a) and (b) overlaid on top of each other, the red shade corresponds to the galvo scanned image, the green shade corresponds to the EWOD prism image, while yellow shade depicts the overlap region between the overlaid images. It can be clearly seen that the cell image preserving the cell shape can be recreated using the distortion correction matrix. (d) Image intensity cross section along y direction obtained from (b). Dendrites of the order of 5µm can be resolved in the image acquired using EWOD prism scanning.

Equations (2)

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cos θ =   cos θ 0 +   ϵ 0 ϵ e f f 2 d e f f γ V 2
V ( t ) = 19.56 ( θ ( t ) ) 0.4949 + 5

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