IoT applications are increasingly becoming widespread with more stringent system requirements. In this work, we demonstrate a nature-inspired integration and packaging technology that achieves self-powered multi-functional systems with optimized performance and small footprint area. The integration technique is based on bifacial usage of the substrate where devices on both sides are interconnected via through-substrate-vias. Multiple substrates are then integrated and folded into a 3D architecture using side-interlocks following a puzzle-like fashion. On the outer sides of the 3D architecture, sensors, RF devices and energy harvesters are integrated while on the inner faces, a solid-state battery in addition to power- management and data-management circuitry are embedded. To package the system, a polymeric encapsulant is used to protect the inner circuitry and enhance the mechanical resilience of the system. Finally, the system is used to send the collected data wirelessly to a phone using an embedded Bluetooth Low Energy unit.