A Rapidly Fabricated Microfluidic Chip for Cell Culture

Abstract

Microfluidic chips (μFC) are emerging as powerful tools in chemistry, biochemistry, nanotechnology and biotechnology. The microscale size, possibility of integration and high-throughput present huge technical potential to facilitate the research of cell behavior by creating in vivo-like microenvironments. Here, we have developed a new method for rapid fabrication of μFC with Norland Optical Adhesive 81 (NOA81) for multiple cell culture with high efficiency. The proposed method is more suitable for the early structure exploration stage of μFC than existing procedures since no templates are needed and fast fabrication methods are presented. Simple PDMS-NOA81-linked microvalves were embedded in the μFC to control or block the fluid flow effectively, which significantly broadened the applications of μFC. Various types of cells were integrated into the chip and normal viabilities were maintained up to 1 week. Besides, concentration gradient was generated to investigate the cells in the μFC responded to drug stimulation. The cells appeared different in terms of shape and proliferation that strongly demonstrated the potential application of our μFC in online drug delivery. The high biocompatibility of NOA81 and its facile fabrication (μFC) promise its use in various cell analyses, such as cell-cell interactions or tissue engineering.

Figure 1.

Sketches of NOA 81 μFC. (A) Fabrication steps for simplest basic μFC: (1) a three-layer μFC with a PDMS cover plate and (2) progress to insert the microvalves; (B) layered schematic representation of the μFC and (C) integral schematic photograph of the μFC (coin diameter 25 mm). This figure is available in black and white in print and in color at JCS online.

Figure 2.

Easily fabricated microvalves. (A) The theory of the simple microvalve; (B) μFC with seven microvalves and (C) cell culture chip with a microvalve (coin diameter 25 mm). This figure is available in black and white in print and in color at JCS online.

Figure 3.

Different dyes passing through the observation chamber during blockage of different pathways (the top channel was pink dye, the middle was water and the lower was blue dye). (A–C) show the sketch map, and crosses represent blocking the flow path where they were located. (D–F) show that different colors of dye or water flow of the observation chamber when the corresponding accesses above were blocked. This figure is available in black and white in print and in color at JCS online.

Figure 4.

SH-SY5Ycells on different substrates (2 × 10⁴/mL, 100×): (A) conventional culture dish substrate; (B) PDMS substrate; (C) NOA 81 substrate; (D) NOA 81's contact angle (53°) and (E) cell viability assay (MTT, 24 h) for NOA81 impregnated liquid in different time periods. This figure is available in black and white in print and in color at JCS online.

Figure 5.

Different time periods, SH-SY5Y cells with EGFP are under optical (A–D, from 1 to 4 days) and fluorescent (E, 3 days) views in the same area. The crosses are designed to ensure that the microscope can collect the same area in different days. (F) SH-SY5Y proliferation line chart in chip and culture dish from 1 to 5 days. This figure is available in black and white in print and in color at JCS online.

Figure 6.

Different cells on the third day (200×): (A) U87, (B) HTC 116, (C) Hela, (D) Hek 293t, (E) bright field of fixed SH-SY5Y with EGFP, (F) merged picture of SH-SY5Y with EGFP cellular staining with DAPI and PI in the same view of (E). This figure is available in black and white in print and in color at JCS online.

Figure 7.

SH-SY5Y (with EGFP) cells were different in terms of shape and proliferation due to DA concentration gradient. This figure is available in black and white in print and in color at JCS online.