*Article* **Polysaccharide** κ**-Carrageenan as Doping Agent in Conductive Coatings for Electrochemical Controlled Release of Dexamethasone at Therapeutic Doses**

**Karla Ramírez Sánchez 1,2,\*, Aura Ledezma-Espinoza 1, Andrés Sánchez-Kopper 1, Esteban Avendaño-Soto 3,4, Mónica Prado 2 and Ricardo Starbird Perez 1,\***


Academic Editor: Mitsuhiro Ebara Received: 13 April 2020; Accepted: 30 April 2020; Published: 3 May 2020

**Abstract:** Smart conductive materials are developed in regenerative medicine to promote a controlled release profile of charged bioactive agents in the vicinity of implants. The incorporation and the active electrochemical release of the charged compounds into the organic conductive coating is achieved due to its intrinsic electrical properties. The anti-inflammatory drug dexamethasone was added during the polymerization, and its subsequent release at therapeutic doses was reached by electrical stimulation. In this work, a Poly (3,4-ethylenedioxythiophene): κ-carrageenan: dexamethasone film was prepared, and κ-carrageenan was incorporated to keep the electrochemical and physical stability of the electroactive matrix. The presence of κ-carrageenan and dexamethasone in the conductive film was confirmed by μ-Raman spectroscopy and their effect in the topographic was studied using profilometry. The dexamethasone release process was evaluated by cyclic voltammetry and High-Resolution mass spectrometry. In conclusion, κ-carrageenan as a doping agen<sup>t</sup> improves the electrical properties of the conductive layer allowing the release of dexamethasone at therapeutic levels by electrochemical stimulation, providing a stable system to be used in organic bioelectronics systems.

**Keywords:** polysaccharide; κ-carrageenan; dexamethasone; electrochemical active deliver system; doping agent; charged molecule; conductive polymers
