A Dual‐Function Micro‐Swiss‐Roll Device: High‐Power Supercapacitor and Biomolecule Probe

Abstract

Tiny autonomous systems less than 1 mm across need small energy storage to satisfy the demand for temporary pulse power and consistent power supply. A battery or supercapacitor alone cannot meet both requirements. Integration of battery and supercapacitor is an alternative, but it introduces a device (supercapacitor) that is not frequently invoked but requires substantial space. Herein, a submillimeter (0.42 mm2) high‐power supercapacitor with an additional function, namely, an on‐chip integrated probe for biomolecule detection is created. The dual‐function device is directly used in the liquid electrolyte, and its Swiss‐roll geometry allows for operation in a minimum 12‐nL electrolyte. The micro‐Swiss‐roll supercapacitor delivers a power density of 911 mW cm−2 and displays a 98% capacitance retention over 10 000 cycles. The biomolecule probe achieves a sensitivity of 230–262 µA mm−1 with a limit of detection of 0.4–0.5 × 10−3 m for the proof‐of‐concept target, the neurotransmitter dopamine. The biomolecule probe achieves a 230–262 µA mm−1 sensitivity with a limit of detection of 0.4–0.5 × 10−3 m for the proof‐of‐concept target, the neurotransmitter dopamine, along with selectivity in the presence of ascorbic acid. The independent dual function provides a promising route toward the full‐time use of dust‐sized supercapacitors integrated into submillimeter functional systems.

Estimating Scalp Moisture in a Hat Using Wearable Sensors

“…The biosensor has monitored the amino acid levels of the wearer to assess the risk of metabolic syndrome. Ferro et al created a submillimeter high-power supercapacitor and a biomolecule probe, which provided a great possibility for the miniaturization of biosensors [ 28 ]. Wang et al proposed a flexible and low-cost humidity sensor with fast responses and successfully applied it to detect human breathing and provide an electrical safety warning for bare hands and wet gloves [ 29 ].…”

Unlocking Micro-Origami Energy Storage

“…24 As a supercapacitor, using electrodeposited PEDOT as the electrode material, it delivers a high power density (up to 911 mW cm −2 ) and good durability (over 10,000 cycles) (Figure 4a, ii). 24 As a biomolecule probe, it also exhibited high sensitivity (230−262 μA mM −1 ) and selectivity in biomolecule detection, specifically dopamine (Figure 4a, iii-v). 24 This micro-Swiss-roll device presents the opportunity to leverage redox electrochemical processes for creating versatile, multifunctional modules in microscale systems.…”

“…24 As a biomolecule probe, it also exhibited high sensitivity (230−262 μA mM −1 ) and selectivity in biomolecule detection, specifically dopamine (Figure 4a, iii-v). 24 This micro-Swiss-roll device presents the opportunity to leverage redox electrochemical processes for creating versatile, multifunctional modules in microscale systems. Furthermore, a Swiss-roll nanobiosupercapacitor (nBSC) with a volume of just 1 nanoliter (1/1000 mm 3 ) has been created, as illustrated in Figure 4b.…”

“…Most of them are cast into a mold and polymerized under ultraviolet (UV) light, but precise on-chip control at a microscale was not explored. A mixed precursor consisting of N-(2-Hydroxyethyl)acrylamide and poly(ethylene- alt -maleic anhydride) can be precisely patterned by photolithography. ,, This photopatternable hydrogel swells in an alkaline solution, generating force for micro-origami. Figure c shows an array of micro-origami self-assembled cubes fabricated with 3D magnetic vector field sensing ability, using the photopatternable hydrogel as hinges .…”

“…Micro-origami energy storage systems are specifically engineered to provide power to various microsystems. Figure a presents a Swiss-roll micro-origami device (0.42 mm 2 ) with dual functions, functioning as a supercapacitor and a biomolecule probe . As a supercapacitor, using electrodeposited PEDOT as the electrode material, it delivers a high power density (up to 911 mW cm –2 ) and good durability (over 10,000 cycles) (Figure a, ii) .…”