471251 Carbon Nanotube-Based Microdevices for Tracking Single Macrophages By Raman Scattering

Thursday, November 17, 2016: 10:54 AM
Golden Gate 7 (Hilton San Francisco Union Square)
Zhibin Wang1, Junfei Xia2, Li Sun3, Phong Tran4, Sida Luo4, Yi Ren3, Tao Liu4 and Jingjiao Guan2, (1)Department of Engineering, Stanford University, Stanford, CA, (2)Chemical and Biomedical Engineering, Florida State University, Tallahassee, FL, (3)College of Medicine, Department of Biomedical Sciences, florida state university, tallahassee, FL, (4)Industrial and Manufacturing Engineering, Florida State University, Tallahassee, FL

Carbon Nanotube-Based Microdevices for Tracking Single Macrophages by Raman Scattering

Zhibin Wang1, Junfei Xia1, Li Sun2, Phong Tran3, Sida Luo3, Yi Ren2, Tao Liu3, Jingjiao Guan1,4

1 Dept. of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University.

2 Dept. of Biomedical Sciences, College of Medicine, Florida State University.

3 Dept. of Industrial & Manufacturing Engineering, FAMU-FSU College of Engineering, Florida State University.

4 Integrative NanoScience Institute, Florida State University


Introduction: The ability to track therapeutic cells in vivo is useful for developing effective cell therapies. Existing cell-tracking techniques such as magnetic resonance imaging and positron emission tomography suffer from the need for ionizing radiation or limited capability for multiplex labelling. In contrast, Raman imaging does not involve ionizing radiation; are highly material dependent and can be excited by NIR, which permits a tissue-penetration depth at the centimeter scale. Carbon nanotubes exhibit strong resonance-enhanced Raman modes and have a unique Raman spectrum. On the other hand, we developed a low-cost, highly versatile technique for fabricating microdevices and preparing the complexes of the microdevices and live cells. We thus extended this method to produce carbon nanotube-based microdevices for tracking single macrophages by Raman scattering.

Fig. A1. Released microdevices. A1. Optical micrograph of cells imaged under a Raman microscope. A2. Macrophage-microdevice complexes. B1. Micrograph of cells and carbon nanotube-based microdevices B2. Raman scattering of the cell enclosed in the square in B1.
Materials and Methods: A polydimethylsiloxane stamp carrying an array of 7 ¦Ìm-diameter circular pillars was coated a trilayer of poly(allylamine hydrochloride) (PAH), and poly (sodium 4-styrenesulfonate) (PSS) and PAH. An aqueous solution of surfactant-stabilized single walled carbon nanotubes dispersed were sprayed on the stamp by using a self-made automatic spraying machine operated by a computer numerical control system. After spraying, poly(lactic-co-glycolic acid) (PLGA) containing a fluorescence dye octadecyl rhodamine B chloride (R18) was spin-coated on carbon nanotubes film surface. The microdevices were transferred onto a poly(vinyl alcohol) (PVA) -coated glass surface and released by dissolving PVA with water. Raman scattering of 785 nm laser by single microdevices was overserved. The microdevices were incubated with mouse bone marrow-derived macrophages to study interactions between the microdevices and the macrophages using fluorescence microscopy and flow cytometry. The viability of macrophages carrying microdevices were investigated by staining the macrophages with calcein AM. Raman scattering of single microdevices were characterized using a Raman microscope and a 5¡Á objective lens.

Results and Discussion: Fig. A1 shows released carbon nanotube-based microdevices loaded with R18 were d in. Fig. A2 shows microdevices were associated to the macrophages after 24 h incubation. Moreover, viability of the cells was not significantly affected by the microdevices. Figs. B1 and B2 show a single macrophage generated the characteristic Raman spectrum of the carbon nanotubes.

Conclusions: We have developed a novel method for fabricating carbon nanotube-based microdevices for tracking single macrophage by Raman scattering. The microdevices are composed of a polyelectrolyte trilayer, carbon nanotubes and PLGA. The Raman signals generated by carbon nanotubes in the microdevices can be detected at a centimeter-scale sample-lens distance under NIR excitation, suggesting this technique may be used in vivo. Moreover, the microdevices can be engulfed by the primary macrophages without affecting viability and phagocytic ability of the cells. Single macrophages carrying the microdevices can be detected by Raman scattering. The microdevices promise to be useful for non-invasive multiplex tracking of single macrophages in vivo.

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