Voltaglue Electroceutical Adhesive Patches for Localized Voltage Stimulation

Abstract

Electroceuticals have been proposed as nerve-and tissue-stimulating therapeutics for diverse ailments such as fracture repair, Parkinson's disease, diabetes, hypertension, and wound healing. However, academic and clinical investigation of electroceutical hypotheses remains intangible due to lack of suitable interfaces required for the application of uniform electric fields to localized tissues. There is an unmet need to develop materials that match the mechanical properties of soft tissues, are electrically conductive, and can flex to accommodate body movements. Herein, the design of a flexible resistive substrate and voltage-activated adhesive-

Precise Control of Diazirine Reduction to Tune the Mechanical Properties of Electrocuring Adhesives

“…Synthesis and structure-property relationships of voltage, current, electrode design, DC/AC signals, cation, and temperature on viscoelastic properties have been previously reported. [22,26,28,[30][31][32] Electric fields are hypothesized to reduce diazirine to a reversible and semi-stable diazirinyl radical (t 1 = 2 = 46 s), that then transitions to a shortlived (6 ns) carbene intermediate. [22,26] The primary evidence supporting this mechanism is diazirine decay, nitrogen gas emission, and rheological viscoelastic transition from viscous to elastic stress deformation (aka gelation) of the high solute (� 50 %) PAMAM-diazirine formulations.…”

“…Voltaglue (VG) consists of a polyamidoamine (PAMAM) dendrimer (generation 5, G5) grafted with diazirine molecules on the surface of the dendrimer. Synthesis and structure‐property relationships of voltage, current, electrode design, DC/AC signals, cation, and temperature on viscoelastic properties have been previously reported [22,26,28,30–32] . Electric fields are hypothesized to reduce diazirine to a reversible and semi‐stable diazirinyl radical (t =46 s), that then transitions to a short‐lived (6 ns) carbene intermediate [22,26] .…”

“…Diazirine offers many methods of activation, including light exposure (photocuring), heating above 80 °C (thermal curing), or voltage (electrocuring). Depending on the activation stimuli, metastable intermediates are formed capable of covalently crosslinking all amino acids [22,24–27] . The electrochemical curing mechanism possesses inherent advantages over heat and light: 1) substrates can be opaque; 2) it avoids temperatures (>60 °C) that denature proteins or exceeds the Tg/Tc of labile biomaterials; 3) it can be precisely controlled externally via microcontrollers.…”

Structure–Activity Relationships of Voltaglue Organic Blends

“…[ 1 ] Crosslinking in Voltaglue can be initiated with diverse electrode geometries such as disposable three‐electrode chips, [ 1,2 ] bioresorbable interdigitated 3D‐graphene electrodes (IDE), [ 3 ] and semiconductive substrates. [ 4 ] Despite these advances, Voltaglue has some limitations (when stimulated/electrocured) in aqueous environments: 1) it displays low storage modulus (1 kPa) in comparison to photo‐ and thermal‐curing (100 kPa) and 2) the water electrolysis that takes place at –1.3 V may lead to excessive foaming. Recently, we reported that most of these disadvantages could be overcome by employing donor–acceptor‐based electrocuring in organic environments.…”

“…Blended formulations may be further optimized with higher voltages or alternating current for faster activation. [ 4,15 ]…”