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Bioelectronic devices hold transformative potential for healthcare diagnostics and therapeutics. Yet, traditional electronic implants often require invasive surgeries and  are mechanically incompatible with biological tissues. Injectable hydrogel bioelectronics offer a minimally invasive alternative that interfaces with soft tissue seamlessly. A major challenge is the low conductivity of bioelectronic systems, stemming from poor dispersibility of conductive additives in hydrogel mixtures. We address this issue by engineering doping conditions with hydrophilic biomacromolecules, enhancing the dispersibility of conductive polymers in aqueous systems. This approach achieves a 5-fold increase in dispersibility and a 20-fold boost in conductivity compared to conventional methods. The resulting conductive polymers are molecularly and in vivo degradable, making them suitable for transient bioelectronics applications. These additives are compatible with various hydrogel systems, such as alginate, forming ionically cross-linkable conductive inks for 3D-printed wearable electronics toward high-performance physiological monitoring. Furthermore, integrating conductive fillers with gelatin-based bioadhesive hydrogels substantially enhances conductivity for injectable sealants, achieving 250% greater sensitivity in pH sensing for chronic wound monitoring. Our findings indicate that hydrophilic dopants effectively tailor conducting polymers for hydrogel fillers, enhancing their biodegradability and expanding applications in transient implantable biomonitoring. Injectable bioelectronics face low conductivity due to poor polymer dispersibility. Here, authors engineer dopants in conductive polymers to boost their water dispersibility 5-fold and conductivity 20-fold, enabling biodegradable, 3D-printable hydrogels for wearables and implantable devices.

Communication with hand gestures plays a significant role in human‐computer interaction by providing an intuitive and natural way for humans to communicate with machines. Ultrasound‐based devices have shown promising results in contactless hand gesture recognition without requiring physical contact. However, it is challenging to fabricate a densely packed wearable ultrasound array. Here, a stretchable ultrasound array is demonstrated with closely packed transducer elements fabricated using surface charge engineering between pre‐charged 1–3 Lead Zirconate Titanate (PZT) composite and thin polyimide film without using a microscope. The array exhibits excellent ultrasound properties with a wide bandwidth (≈57.1%) and high electromechanical coefficient (≈0.75). The ultrasound array can decipher gestures up to 10 cm in distance by using a contactless triboelectric module and identify materials from the time constant of the exponentially decaying impedance based on their triboelectric properties by utilizing the electrostatic induction phase. The newly proposed metric of the areal‐time constant is material‐specific and decreases monotonically from a highly positive human body (1.13 m2 s) to negatively charged polydimethylsiloxane (PDMS) (0.02 m2 s) in the triboelectric series. The capability of the closely packed ultrasound array to detect material along with hand gesture interpretation provides an additional dimension in the next‐generation human‐robot interaction. A stretchable ultrasound array, created through surface charge engineering, demonstrates effective contactless hand gesture recognition and material detection. The array demonstrates excellent ultrasound properties, interprets gestures up to 10 cm away, and identifies materials based on their triboelectric properties. The proposed material‐specific areal‐time constant metric enhances human‐robot interaction, offering a new dimension in communication.

Glassy carbon electrode (GCE) was modified with six novel solid-phase nanocomposites as substrate for non-enzymatic hydrogen peroxide (H2O2) sensor have been utilized in this study. This work was conducted to study the effect of different novel solid-phase nanocomposites with different morphologies toward H2O2, and also evaluate and enhance the performance of modified glassy electrodes with the prepared nanocomposites as hydrogen peroxide sensor. The first four composites were based on polyaniline as the polymer matrix. Silver nanoparticles-polyaniline nanotubes (AgNPsPANINTs(A)) composite prepared via one-step modified free chemical template method and AgNO3 was used as the source of Ag nanoparticles (AgNPs). By reducing the temperature of the reaction, the nanotube morphology changed to rod shape and silver nanoparticle-polyaniline nanorods (AgNPs-PANINRs) composite is obtained. The AgNPs-PANINRs composite exhibited better electrochemical performance toward H2O2 detection with limit of detection (LOD) of 0.13 µM as compared to AgNPs-PANINTs(A) composite, due to higher surface area and content of AgNPs. The source of silver changed to Ag(NH3)2OH instead of AgNO3 in nanotube morphology of nanocomposite to get better distribution of AgNPs. The performance of the obtained composite (AgNPsPANINTs(B)) with LOD of 0.6 µM significantly improved as compared to the nanotube composite prepared with AgNO3 as a source of silver. The combination of two different methods in synthesizing of the forth nanocomposite was conducted to obtain a better performance of materials for sensing H2O2. Silver nanoparticle-reduced graphene oxidepolyaniline nanofibers (AgNPs-PANINFs-rGO) were synthesized using two-step method. PANINFs were prepared in the presence of sulfuric acid applying vertical sonochemical method. AgNPs-rGO, which was prepared separately by hydrothermal method, was dropped on the surface of GCE followed by PANINFs to fabricate the modified electrode. The modified electrode was prepared by dropping the obtained AgNPs-rGO and PANINFs on the glassy carbon electrode (GCE). The prepared modified electrode shows LOD of 0.117 µM. This composite indicated smaller LOD as compared to AgNPs-PANINTs(B) and AgNPs-PANINRs composites due to the presence of rGO. The two last composites are carbon-based composites. Silver nanoparticles-reduced graphene oxide-carbon nanotubes (AgNPs-MWCNT-rGO) were prepared using two different methods which are hydrothermal (AgNPs-MWCNT-rGO(H))and electrochemical (AgNPs-MWCNT-rGO(E)). These methods provided the notable advantage of a single-step reaction without employing any toxic solvent or reducing agent by providing a novel green synthetic route to produce the AgNPS-MWCNT-rGO.The hydrothermal AgNPs-MWCNT-rGO(H) composite exhibited a LOD around 0.9 µM. Finally, the electrodeposited AgNPs-MWCNT-rGO(E) composite displayed LOD of 1.4 µM that is less than hydrothermal composite. All the synthesized nanocomposites were characterized by using X-ray Diffraction, Field Emission Scanning Electron Microscopy, Transmission Electron Microscopy and Atomic Force Microscopy meanwhile the reactivity of the prepared composites towards H2O2 were analyzed using cyclic voltammetry and chronoamperometry. All the nanocomposites modified electrodes exhibited excellent electrocatalytic activity for the reduction of H2O2 with a fast amperometric response time less than 3 s. Among all six prepared nanocomposites, AgNPs-PANINFs-rGO composite is the best solid-phase nanocomposites system forH2O2detection with LOD = 0.117 µM.