Tailoring PLA surface with anchor lipids to fabricate transmembrane protein-loaded nanometric bioresorbable platform. 1 IMEM-BRT Group, Departament d’Enginyeria Química, EEBE, Universitat Politècnica de Catalunya, C/ Eduard Maristany 10-14, Ed. I2, 08019 Barcelona, Spain 2 Barcelona Research Centre for Multiscale Science and Engineering, EEBE, Universitat Politècnica de Catalunya, C/ Eduard Maristany 10-14, Ed. I-S-1, 08019 Barcelona, Spain 3 Biological and Chemical Research Centre, Faculty of Chemistry, University of Warsaw, Zwirki i Wigury 101, Warsaw 02-089, Poland ahammed.hussain.madhani@upc.edu @m_s_a_h_m_8_6 1. Introduction In biomedicine, bioresorbable sensors hold great promise due to their ability to breakdown and resorb after use. As a result, patients wouldn't have to undergo a second, potentially risky surgical procedure to have non-bioresorbable sensors removed. However, developing reliable, biodegradable sensors remains difficult. In order to create such platform for biosensing that can support artificial lipid bilayers and transmembrane proteins such ion channels as biomimetic models, this research was initiated with the overarching goal of mimicking the cellular environment. The well-studied channel-producing peptide gramicidin (gA)(1) served as a template for this work. Acknowledgements This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No.955643 3. Conclusions Self-assembly, alkaline hydrolysis, and surface activation were the three stages of development that yielded a functional bioresorbable platform. The lipid layers were anchored to the polymeric scaffold with poly(ethylene glycol)-cholesterol (Chol-PEG- NH2). Furthermore, electrochemical impedance spectroscopy (EIS) was employed to detect the transport of monovalent cations on the polymeric substrate using Gramicidin A (gA). These lipid- and transmembrane-protein-based biomimetic systems hold great promise for future biofiltration and biosensing technologies.(2) This research provides a novel bioinspired method for fabricating a completely bioresorbable and biocompatible platform. 1) Zhangfei Su et al. Electrochim Acta, 2017 343 ,364 372 2) Mohammed-Sadhakathullah et al. Int. J. Mol. Sci. 2023, 24, 10312. 3500 1500 -0.05 0.00 0.05 0.10 0.15 0.20 DAbsorbance (a.u) Wavenumber (cm-1) PLA-PEG-Chol PLA-EDC PLA-NaOD C=O Amide C-H -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 PLA PLA-PEG-Chol PLA-PEG-Chol-DMPC PLA-PEG-Chol-DMPC-gA s / mC cm-2 E / V vs Ag|AgCl -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0 5 10 15 20 25 30 35 40 PLA PLA-PEG-Chol PLA-PEG-Chol-DMPC PLA-PEG-Chol-DMPC-gA C / mF cm-2 E / V vs Ag|AgCl 1M 0 50k 100k 150k 200k 250k 300k 350k 0.0 500.0k 1.0M 1.5M 2.0M 2.5M 3.0M PLA PLA-PEG-Chol PLA-PEG-Chol-DMPC PLA-PEG-Chol-DMPC-gA Z'(Ohm) -Z''(Ohm) -1 0 1 2 3 4 5 2 4 6 Log Z/ Ohm -F/ deg Log F/Hz 0 20 40 60 80 100 PLA PLA-PEG-Chol PLA-PEG-Chol-DMPC PLA-PEG-Chol-DMPC-gA R1 R2 CPE1 CPE2 PLA-PEG-Chol-DMPC-gA R1 R2 CPE1 PLA-PEG-Chol-DMPC 0 50k 100k 150k 200k 0.0 300.0k 600.0k 900.0k PLA-PEG-Chol-DMPC-gA with Ca2+ Z'(Ohm) -Z''(Ohm) -1 0 1 2 3 4 5 2 3 4 5 6 7 0 20 40 60 80 100 PLA-PEG-Chol-DMPC-gA with Ca2+ Log Z/ Ohm Log F/Hz -F/ deg Cholesterol-PEG-Amine Anchor Lipid Au Self assembled monolayers (SAM) Poly (Lactic acid) (PLA) Surface modification Gramicidin 2. Results 3500 1500 0.00 0.05 C-H C=O DAbsorbance (a.u) Wavenumber (cm-1) PLA-PEG-Chol-1H PLA-PEG-Chol-2H PLA-PEG-Chol-4H Fig 1. Change in the frequency w.r.t time Different lines correspond to 3,5,7,9,11 harmonics. Quartz Crystal Microbalance (QCM-D) ❑The quartz crystal microbalance (QCM-D) can spot changes in mass per unit area as little as a nanogram. Accordingly, as mass is added to the surface, the frequency decreases. Electrochemistry A B C D E F G Fig 4. Electrochemical characterization of PLA after every step (A-D) (A). Potential of Zero charge. (PZC) (B). AC Voltammetry (ACV) and (C,D).