Highly Integrative Artificial Cell Membrane Microarray


Kazuaki Furukawa
Materials Science Laboratory

 Microarrays of biological molecules such as DNA chips are widely used for high-throughput bioanalysis. When developing new microarrays, it is essential to improve the technology for fixing biomolecules without losing their biological functionality. A microarray consisting of an artificial cell membrane supported on a solid surface is expected to provide an important platform for the purpose. We have developed a new technique for fabricating an artificial cell membrane microarray and demonstrated a biosensing application of the fabricated microarray.
 We used the self-spreading phenomenon, which is a self-organizing process that forms a cell membrane at a solid-liquid interface, to fabricate the artificial cell membrane microarray. Our method is unique in that the position of the self-spreading is controlled with a hydrophilic/hydrophobic pattern [1]. According to the designed pattern, a self-spreading membrane starting from a macroscopic area was guided to the microarray structure without mixing with membranes in the different areas. We succeeded in fabricating 10-µm-width parallel lines, each filled with an artificial cell membrane with a unique composition, at 5-µm intervals (color frontispiece). Structures obtained with our new technique are in principle more than 100 times more highly integrated than previously reported structures that employ the vesicle fusion technique on patterned surfaces [2].
 To demonstrate the validity of the microarray for biosensing applications, we fabricated a composition microarray, part of which contained biotin-conjugated lipid. Figure 1 shows fluorescence images of the array that were recorded (a) before and (b) after it was immersed in Texas Red conjugated streptavidin solution. Red fluorescence, which originates from Texas Red, was observed only in the lines containing biotin-conjugated lipids after 90 min, as shown in Fig. 1(b). This is due to the specific binding between biotin and streptavidin. Since the red fluorescence from the lines without biotin is limited, the microarray is valuable for biosensing applications.
 This work was supported by KAKENHI.

[1] K. Furukawa et al., Lab Chip 6 (2006) 1001.
[2] K. Furukawa and T. Aiba, Langmuir 27 (2011) 7341.

Fig. 1. Fluorescence images of artificial cell membrane microarray (a) before and (b) 90 min after the addition of Texas Red conjugated streptavidin solution. The membranes are composed mainly of Egg-PC with top 3 lines: 1 mol% NBD-conjugated lipid; middle 3: 1 mol% biotin-conjugated lipid; bottom 3: both lipids. The green and red fluorescence is from NBD and Texas Red, respectively, and the green & red image in (b) is a superimposition of two images, green and red.

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