A 3D microelectrode device includes a flexible substrate containing poly-dimethyl siloxane (PDMS). The device may be fabricated in a miniature form factor suitable for attachment to a small organ such as a lateral gastrocnemius muscle of a live rat. In addition to providing a miniaturized, conformable attachment, the device provides an anchoring action via one or more microelectrodes, each having an insertable tip particularly shaped to provide the anchoring action. Furthermore, a base portion of each of the microelectrodes is embedded inside conductive poly-dimethyl siloxane (cPDMS). The cPDMS is contained in a pad that is coupled to a conductive track embedded in the flexible substrate. Embedding of the base portion inside the cPDMS material not only allows the microelectrode to bend in various directions, but also provides good electrical conductivity while eliminating the need for attachment processes using solder or epoxy adhesives.