Most optical and electronic biosensors are rigid and inherently planar. However, many biological objects such as nanoparticles, cells and organisms are three dimensional. Consequently, the area of measurement between a 2D chip based biosensor and the 3D object is limited which can result in low signal to noise ratios and limited 3D spatiotemporal information. Here, we describe a new class of biosensors in the form of self-folding shells that can be flexible and wrap around 3D objects such as cells. The biosensors can be fabricated en masse and used either on or off chips. The sensors are composed of ultrathin materials such as silicon based thin films or even functionalized single layer graphene which can be easily be bent, curved or folded into 3D geometries. Consequently, when designed appropriately, such as with thermally responsive polymer brushes or differentially stressed bilayers they can self-fold and wrap around 3D objects and live cells. Further, when patterned with gold nanostars or metal electrodes they can enable SERS mapping or electrical measurements of the activity of cell membranes. We detail the design, self-folding and utilization of these microstructures as shell based optical and electrical sensors for 3D spatiotemporal biosensing.

Ultrathin shell biosensors for 3D live cell studies

256th National Meeting (2018)

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