Vacuum casting to manufacture a plastic biochip for highly parallel cell transfection

A novel polymer microarray fabrication technique is presented and applied to the realization of a biochip for highly parallelized cell transfection. The proposed microfabrication technique is derived from a macroscale rapid prototyping technique called vacuum casting. It was optimized to reduce production cost, in order to produce small series (100-10000 chip series) of chips to meet demand in today's market of cellulomics. Microfabrication technologies and rapid prototyping technologies are combined to shape the master part, which can thus involve microsized features. The corresponding female structure is moulded in a flexible silicone material. The duplicated polymer chips are obtained by casting a thermosetting plastic under vacuum. The dimensional replication accuracy between the master part and the duplicated parts is uniform over the duplicated parts and better than 1%. Advantages of the proposed technique over existing plastic microfabrication techniques are discussed in the paper. Using this microfabrication technique, we produced a plastic biochip for highly parallelized transfection of arrays of living cells. The feasibility of parallel lipofection was demonstrated: two different plasmids encoding, respectively, eGFP and DsRED2 were inserted into HEK293T cells. The transfection was monitored through fluorescence observation after 72 h showing successful expression of both genes.