A Conductive Hydrogel Microneedle‐Based Assay Integrating PEDOT:PSS and Ag‐Pt Nanoparticles for Real‐Time, Enzyme‐Less, and Electrochemical Sensing of Glucose

Abstract

Continuous glucose meters (CGMs) have tremendously boosted diabetes care by emancipating millions of diabetic patients' need for repeated self-testing by pricking their fingers every few hours. However, CGMs still suffer from major deficiencies regarding accuracy, precision, and stability. This is mainly due to their dependency on an enzymatic detection mechanism. Here a low-cost hydrogel microneedle (HMN)-CGM assay fabricated using swellable dopamine (DA)-hyaluronic acid (HA) hydrogel for glucose interrogation in dermal interstitial fluid (ISF) is introduced. Platinum and silver nanoparticles are synthesized within the 3D porous hydrogel scaffolds for nonenzymatic electrochemical sensing of the glucose. Incorporation of a highly water dispersible conductive polymer, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) enhances the electrical properties of HMN array, making the patch suitable as the working electrode of the sensor. The in vitro and ex vivo characterization of this newly developed HMN patch is fully studied. The performance of the HMN-CGM for real-time measurement of glucose is also shown using a rat model of type 1 diabetes. The device introduces the first HMN-based assay for tracking important disease biomarkers and expect to pave the way for next generation of polymeric-based sensors.

Fabrication and Characterization of Porous Microneedles for Enhanced Fluid Injection and Suction: A Two‐Photon Polymerization Approach

“…The load was divided by the number of MNs to identify the maximum load one MN can withstand, and the porous (open tip) MN could handle a compression force of 0.596 N per MN, comparable to that found in the literature. [ 32,42–44 ] The hollow MN could withstand a force of 0.576 N and the porous (closed tip) a force of 0.556 N. This proves that when using this design and fabrication technique, the additional pores do not significantly affect the mechanical stability of the MN.…”

Cell Viability Assessment of PEDOT Conducting Polymer-Coated Microneedles for Skin Sampling

“…However, since an epidermal electrode is mainly in contact with the SC, the in vitro biocompatibility study would be more relevant to test with keratinocytes instead of fibroblasts. Another paper using a PEDOT/PSS hydrogel MN for glucose sensing in ISF also showed good viability when the MN electrodes were placed directly on the mouse fibroblast cells . More relevant work using human dermal fibroblast (HDF) cells was reported by Niu et al, where a PEDOT coating on microfibrous poly­(lactic acid)­(PLLA) induced no cytotoxicity and supported adhesion, migration, and proliferation of the cells .…”

“…The most common CPs in wearable electrochemical sensors are polypyrrole (PPy), poly(3,4ethylenedioxy-thiophene) (PEDOT), and polyaniline (PANi), due to long-term electrical and chemical stability. 15 For example, PEDOT doped with tosylate (TOS) and polystyrenesulfonate (PSS) showed stable electrochemical impedance when exposed to skin lysate for 24 h. 22 To date, numerous papers have reported biocompatibility testing on PEDOT and its derivatives, especially in the context of tissue engineering: for example, in nerve tissue, 23 biosensors, 24 and drug delivery. 25 The biocompatibility of PEDOT in multiple forms or formats has also been reported, such as fibers, 26 hydrogels, 27 and plastic.…”

“…Another paper using a PEDOT/PSS hydrogel MN for glucose sensing in ISF also showed good viability when the MN electrodes were placed directly on the mouse fibroblast cells. 24 More relevant work using human dermal fibroblast (HDF) cells was reported by Niu et al, where a PEDOT coating on microfibrous poly(lactic acid)(PLLA) induced no cytotoxicity and supported adhesion, migration, and proliferation of the cells. 34 Similarly, PEDOT-coated PLA or poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV, showed no cytotoxic effect on HDF cells.…”

High-Work-Function 2D Perovskites as Passivation Agents in Perovskite Solar Cells

“…Among them, salts that form 2D perovskites have been used for the passivation of perovskite, leading to improved efficiency and stability. ,− Sometimes, if these salts are used in the precursor of perovskite, they tend to form a layered material with the general formula of R 2 (A) n– 1 B n X 3 n+ 1 ( n = 1, 2, 3, 4,···) where n is the number of layers in the Ruddlesden–Popper phase. , However, if these salts are introduced after annealing the primary 3D perovskite with excess lead, they form a uniform 2D perovskite coating on the surface of the 3D perovskite . The mechanism for the enhanced photovoltaic performance of 2D passivated PSCs is believed to be due to the passivation of the grain defects. − Some passivating agents applied to improve photovoltaic parameters contain functional groups, − potentially providing alternative mechanisms to further enhance the performance. Although salts are intrinsically polar, the anion and cations will orient and distribute in a way that has a net zero dipole moment.…”