© 2014 Elsevier B.V. Increasingly, advances in microtechnologies are focused on obtaining new chips intended for applications in fields such as nanomedicine and cell biology, taking advantage of the ability of microelectronics to manufacture devices with cell dimensions and a large variety of features. Here, we report a technology for the fabrication of multi-material chips, using polysilicon and gold as device layers, to be used as bi-functional cell-internalizable devices. In our case, one of the main technological challenges is to overcome the low adherence between these two materials, especially because of their small contact-area, only 9 μm2. Thus, in order to circumvent this difficulty a chromium adherent-layer was deposited in between. After fabrication, the devices following this design can be successfully internalized inside living macrophages without affecting their viability. The advantage of having multiple material layers in one device is the potential to render multi-tasking chips, as once they are appropriately functionalized, we can provide the chip the ability of being multi-functional. Hence, and as a proof of concept, two different proteins, Wheat Germ Agglutinin (WGA) and Concanavalin (ConA), were immobilized on the chip surface through self-assembled monolayers using orthogonal chemistry. The results of this work show a well-controlled fabrication, the bi-functional capabilities and no cell-toxicity of intracellular polysilicon-chromium-gold chips. Eventually, two different dyes (Oregon Green® 488 and BODIPY® 581/591) were used to bi-functionalize each surface of the multi-material chip in order to demonstrate that functional chips can also be internalized in living cells. These devices have a promising future as intracellular functional platforms for biosensing, drug delivery and diagnosis.
- Intracellular chips
- rthogonal biofunctionalization