【助成 38 -27】
リポソームとナノフォトニック共振器のインタフェース

研究者 東京理科大学 理学部 准教授 Sadgrove Mark Paul

〔研究の概要〕Liposomes are biological nano-particles made from lipid bilayers. Liposomes have the same structure as cells,
but they do not have a cell nucleus. For this reason, liposomes make an excellent test platform to develop
manipulation techniques for living cells, and other bio-particles such as exosomes. In this research project, theapplicant’s goal was to create a nanophotonic platform to i) Transport and trap liposomes on a nanowaveguide(optical nanofiber) and ii) couple the liposomes to a nanowaveguide cavity. These novel techniques could provide
new opportunities for diagnosis of diseases, or the realization of biological systems in quantum regimes.

〔研究経過および成果〕
Background: Liposomes are biological nano-particles
made from lipid bilayers as shown in Fig 1. Liposomes
have the same structure as cells, but they do not havea cell nucleus. For this reason, liposomes make anexcellent test platform to develop manipulation

Figure 1：Concept of trapping and transporting

techniques for living cells, and other bio-particles

of liposomes using an optical nanofiber.

such as exosomes. Use of nanowaveguides will allow
the development of integrated optical circuits fortrapping, transport and analysis of nanoparticles. Thismethod could allow new miniaturized technology for
analysisof

bio-nanoparticles.

However,forbio-nanoparticles such as liposomes, two large
problems

exist:i)particles

adhereto

thenanowaveguide surface and ii) particles are very
difficult to trap because of very low refractive index.
In this research project, we proposed the creation of ananophotonic platform to i) Transport and trap
liposomes on a nanowaveguide (optical nanofiber) (seeFigure 1) and ii) couple the liposomes to ananowaveguide cavity. Below, we will detail ourachievements related to this project.
Research results
In December 2021, we reported the first use of an
nanowaveguide (an optical nanofiber) to transport
Liposomes. These liposomes had a sub-micron
diameter (size distribution shown in Fig. 2(a)), making
them the same size as liposomes used for typicalapplications in medical drug development, etc. Our
method of manipulation is very simple, as shown in Fig.
2(b). An optical nanofiber (diameter 300 ~ 550 nm)

made from a commercial optical fiber is placed in aMatsuyama, M Komiya, T Yoshino, D Yamaura,

droplet of water containing liposomes. The liposomes

Yasuyoshi

are optically trapped in the evanescent field of the

Hirano-Iwata, Optical Manipulation and Its

nanofiber by injecting a 785 nm laser into the fiber. AApplications 2021, AW4D. 4 (2021).

Mitsumori,K

Edamatsu,

A

540 nm laser is also introduced to make the３． Some topics in nano-particle transport using

dye-tagged liposomes photoluminescence (PL) so

nanofibers M Sadgrove, Metanano (2021).

that they can be imaged. Optical trapping and４． Optical manipulation of low index contrast

transport are viewed as shown in Fig. 2(c) where ananoparticles with a nanofiber Akiyoshi Suda,

liposome moves along the fiber in the same direction

Risa Matsuyama, Mika Shimura, Maki Komiya,as the optical mode. These images are focused using

Ayumi Hirano-Iwata, Mark Sadgrove, Pacifichem

an objective lens (OL) and recorded on a standard(2021).

CMOS digital camera. Our results showed that

５． 共振器を用いたキラルな単一光子源に向けて

thinner nanofibers performed more efficiently to trap

白根森斗, Mark Sadgrove, 日本物理学会 2021

and transport liposomes, with 360 nm diameter fibers

年秋季大会 (2021).

showing higher transport speeds and longer trap times

６． Optically induced sieve effect for nanoparticles

compared to a 550 nm diameter fiber. We also

near a nanofiber taper M Sadgrove, T Yoshino,

analyzed the experiment theoretically, and our results

M Sugawara, Y Mitsumori, K Edamatsu Physicalsuggested that most of the observed behavior could

Review Applied 16, 044034 (2021).

be explained by optical forces as opposed to heatingeffects. These results were reported in Optics Lettersin 2021 [1] and at conferences in the same year [2-4].
Our future plans involve the use of bottle resonators
which we realized in 2021 [5]. We plan to trap
liposomes near to the resonator using a taper trap [6].
〔発表論文〕
１． Optical transport of sub-micron lipid vesicles
along a nanofiber T Yoshino, D Yamaura, M
Komiya, M Sugawara, Y Mitsumori, M Niwano, A
Hirano-Iwata, K. Edamatsu, M Sadgrove, Optics
Express 28, 38527-38538 (2020).
２． Liposome manipulation using the evanescent fieldof an optical nanofiber M Sadgrove, A Suda, RFigure 2 (a) Liposome size distribution. (b)Experimental setup. (c) Frames of movie showing
liposome trapping and transport.