Screen-Printed Hybrid Electrodes for Detecting and Monitoring Lipopolysaccharides TOXINSENS-255PED/2020
Project Partners and Institutions:
CS I. Dr. eng. Tanta-Verona IORDACHE, Leader of Team 1, Advanced Polymer Materials and Polymer Recycling Group, Polymers Department, INCDCP-ICECHIM
National Research & Development Institute for Chemistry and Petrochemistry-ICECHIM, Bucharest, Romania (www.icechim.ro)
Professor Dr. eng. Catalin ZAHARIA, Director of Department of Bioresources and Polymer Science, Faculty of Applied Chemistry and Material Science, Politehnica University of Bucharest,
Eng. Petru EPURE, Administrator at EPI-SISTEM S.R.L. Brasov,
Politehnica University of Bucharest, www.upb.ro·
EPI-SISTEM S.R.L. Brasov, www.epi.ro
National Funding Agencies
Unitatea executiva pentru finantarea invatamantului superior, a cercetarii, dezvoltarii si inovarii (UEFISCDI)
https://www.uefiscdi.ro/UEFISCDI contract no. 255PED/2020;
UEFISCDI Contract budget: 600 000 RON
EPI-SISTEM Brasov Romania, www.epi.ro: 36 000 RON
Duration of project: 24 months (start date:03 August 2020)
The project TOXINSENS refers to dsigning innovative, versatile and re-usable biosensors for the fast,qualitative and quantitative detection and monitoring of popolysaccharides(LPS- endotoxin derived from Gram-negative bacteria, GNB) in various biological, food or water samples. For this matter, a medium consortium was created taking into account the project interdisciplinary and complexity, which includes the Project Coordinator ICECHIM that owns the background of the Concept approached in this project proposal, a Partner with state-of-the art facilities for characterisation i.e. UPB and a SME Partner-EPI SISTEM SRL capable of testing the project prototypes, adsorbing the know-how of manufacturing and commercialise the resulted LPS-biosensors. The project on-set refers to the following bioinspired concept: Methodology for the preparation of LPS-sensitive films-TRL 2. The concept was originally proposed by the Project Leader and developed within the Advanced Polymer Materials & Polymer Recycling Group from ICECHIM on project TE123/2018 BACTERIOSENS. Starting from this point, TOXINSENS targets first the upgrade of this former concept by addition of electro-active nanoparticles to the precursor films solution. In this way, an electro-active hybrid paste will be generated and used to print LPS-hybrid films directly on blank ceramic electrodes (TRL 3). The prepared LPS-Screen-printed hybrid electrodes will be further tested in laboratory -relevant environments and the innovative technologies will be thus validated (TRL 4). The specific output of the project will lead to several outcomes during project implementation (short-term scenario: at least 3 publications, 3 communications at prestigious Symposia or Congresses and 1 patent claim), and also after project end long-term scenario: research and development roadmaps, performance data, transferable knowledge).
The project general objective targets the use of the scientific fundamental background generated on Project TE123/2018 (which is the only knowledge available at this moment at national and international level) to move to a higher level of technological maturity (demonstrator and laboratory validated technology). In this way, the capacity to generate validated solutions in the laboratory for significantly improved products (i.e. the LPS-Screen-printed hybrid electrodes), know-how (for the LPS electro-active hybrid paste and for the adjusted 3D printing methodologies) and preparation technologies (for the LPS-Screen-printed hybrid electrodes) of the involved RT&D Organizations (ICECHIM and UPB) will be enhanced and the SME partner (EPI SISTEM) will be the first to benefit of these solutions.
(1) Precursor solutions for LPS-hybrid films and Preparation Methodologies; (2) Intermediary Product Sheet; (3) LPS-hybrid films and Preparation Methodologies; (4) adapted 3D Printing Methodologies; (5)Test Performance Report of LPS-hybrid films; (6) Product Sheet; (7) LPS-Hybrid Biosensor Prototypes and Preparation Methodologies; (8) Test Performance Report for the LPS-Hybrid Biosensor Prototypes; (9) LPS-Hybrid Biosensors; (10) Preparation Laboratory Technology for the LPS-Hybrid Biosensors; (11)DEMO Report for the functionality of LPS-Hybrid Biosensors; (12)Three conference paper communications; (13) Scientific papers, 3 ISI papers sent for publication; (14) Specific Website of the project “TOXINSENS”; (15) Patent Application on the design and preparation of LPS-screen printed hybrid electrodes.
Project Partners would like to thank UEFISCDI for sustaining and funding the research activity performed in TOXINSENS project.
Team Staff from INCDCP-ICECHIM
Team Staff from Politehnica University of Bucharest (P1)
Team Staff from EPI-SISTEM S.R.L. (P2)
PHASE I: THE OBTAINING OF PRECURSOR SOLUTIONS FOR HYBRID FILMS PRYNTING
PHASE PERIOD: 03.08-31.12.2020
Activity 1.1 Preparation of the precursor solutions for hybrid films (Responsible: EPI SISTEM, ICECHIM)
Activity 1.1.1 Studies on the required specifications for the preparation of the electroactive precusor paste (viscosity and thermal stability) and on the establishment of a commercial reference
Activity1.1.2 Preparation of precursor solutions for hybrid films with electroactive nanoparticles (carbon or metal oxides) to obtain a printable paste
Activity 1.2 Physico-chemical characterizations of the precursors (Responsabili: UPB, ICECHIM)
Activity 1.2.1 Morphological and structural characterization of the raw materials by SEM/microCT, XPS/DLS and the determination of thermal stability (TGA/DTG, DSC) of the precursor solutions.
Activity 1.2.2 FTIR structural characterization and determination of viscosity (Rheometry) of precursor solutions
Activity 1.3 Communication and dissemination of results at national or international conferences and publication of papers in journals indexed by the web of science
Activity 1.3.1 Communication and dissemination activities of the results
Activity 1.3.2 Communication and dissemination activities of the results
In Stage I/2020 the partner EPI-SISTEM S.R.L. presents the studies regarding the necessary specifications for the preparation of precursor electroactive paste (viscosity and thermal stability) and the establishment of a commercial reference. In this regard, in order to make a small serie of screen printed electrodes, 3 procedures will be approached: classic screen printing, inkjet printing and 3D printing. A screen-printed electrode model (screen-printed masks on A5 formats) was made and high-temperature-resistant substrate types such as polyimide, Kapton, fiberglass-reinforced silicone were prepared. A commercial reference and the technical specifications that the electroactive material must fulfill in order to be printed in optimal conditions, for preparing the screen-printed electrodes for detecting lipopolyssacharides, was established.
ICECHIM coordinator successfully prepared several series of molecularly imprinted particles with LPS and the control non-imprinted ones by sol-gel technique, using several stabilizers. The precursor solutions for hybrid films with electroactive nanoparticles in the form of printable paste were prepared using in this first stage both particle types, imprinted with LPS and non-imprinted. The recipe for preparing the precursor solutions was in good accordance with the properties that the electroactive material must fulfill in order to be printed on the screen-printed electrodes by EPI-SISTEM Partner.
ICECHIM together with UPB Partner performed physico-chemical characterizations of the precursors by FTIR spectroscopic analyzes, BET porosimetry, morphological-dimensional DLS, thermal TGA / DTG, UV-Vis spectrometric and determination of the viscosity of the precursor solutions. The FTIR spectra of all synthesized particles and electroactive precursors confirmed the presence of the LPS template in the matrix, by characteristic vibrations of OH (ν-OH) bonds belonging to phosphate groups and glucosamine molecules recorded in the region 3450-3200 cm-1 (intense wide band). The dynamic light diffusion (DLS) analysis revealed a narrow polydispersity and a monomodal distribution in the range of 500-600 nm for the LPS imprinted polymer particles. For the reference samples (without LPS template) unstable dispersions could be observed, with formation of aggregates and bimodal distributions. N2 adsorption-desorption isotherms have shown to be type IV according to IUPAC, with a hysteresis curve characteristic of mesoporous structures. BET analysis showed that both the specific surfaces and the surface areas and volumes of pores are significantly larger for the MIP imprinted particles compared to those of the control particles. The thermal decomposition mechanism of the
imprinted polymers differs from that of the non-imprinted polymers due to the presence of LPS, with higher mass losses in the case of MIP. MIP particles are slightly more stable (due to LPS-matrix interactions) and more homogeneous than NIP homologous.
The electroactive precursor solutions with LPS imprinted particles and non-imprinted particles showed a pseudo-plastic flow in the range of low shear gradients (0-100 s-1) and a quasi-Newtonian at higher shear gradients (100-1300 s-1). The most appropriate rheological behavior for a reference solution for printing hybrid pastes on electrodes was concluded to be the closest to Newtonian.
1. Elena-Bianca Stoica, Ana-Mihaela Gavrila, Andrei Sarbu, Andreea Miron, Marius Ghiurea, Bogdan Trica, Valentin Raditoiu, Razvan Botez, Iulia Elena Neblea, Tanta-Verona Iordache, Electrochemical sensor based on molecularly imprinted polymers for lipopolisaccharides detection, PRIOCHEM XVI, 28-30 Octomber 2020, Bucharest, Romania (oral communication).
1. Bianca Elena Stoica, Ana-Mihaela Gavrila, Andrei Sarbu, Horia Iovu, Hugues Brisset, Andreea Miron, Tanta-Verona Iordache, Uncovering the behaviour of carbon screen printed electrodes modified with lipopolysaccharide-molecularly imprinted polymers, trimis spre publicare Electrochemistry Communication, revizie majora (IF = 4.333)
2. Ana-Mihaela Gavrila, Simona Nedelcu-Flor, Andrei Sarbu, Teodor Sandu, Andreea Olaru, Gheorghe Hubca, Dan Donescu, Tanta-Verona Iordache, Synthesis and properties of organosilica particles with quaternary ammonium bearings as bacteriostatic interfaces, trimis spre publicare U.P.B. Scientific Bulletin 2020, ISSN 1223-7027.
In order to support the activity of dissemination, EPI SISTEM Partner has created a web page http://www.tehnoadvice.ro/toxinsens.html where the summary of the 2020 stage will be presented.
PHASE II: 3D PRINTING OF HYBRID FILMS AND THEIR TRANSPOSITION ON SCREEN PRINTED ELECTRODES
PHASE PERIOD: 01.01-31.12.2021
2.1 Hybrid film printing by 3D technique on plain plastic or ceramic (Responsible: EPI SISTEM, ICECHIM)
Activity 2.1.1 Printing films based on electroactive nanoparticles by 3D technique on plastic or ceramic support
Activity 2.1.2 Study of the adhesion, time and maturation temperature of hybrid films deposited on plastic/ ceramic support
Activity 2.2 Physico-chemical characterizations of the hybrid films (Responsible: UPB, ICECHIM)
Activity 2.2.1 Morphological (SEM / microCT), structural (XPS, FTIR) characterization, contact angle measurements and thermal analysis (TGA / DTG, DSC) of hybrid films
Activity 2.2.2 Determination of LPS specificity of hybrid films (static adsorption via UV-vis)
Activity 2.3 Hybrid films printing by 3D technique on electrodes to obtain Hybrid Biosensors (Responsible: EPI SISTEM, ICECHIM)
Activity 2.3.1 Printing films based on electroactive nanoparticles by 3D technique on electrodes
Activity 2.3.2 Hybrid film optimization in terms of electrode sensitivity for LPS (cyclic voltammetry)
Activity 2.4 Physico-chemical characterizations of hybrid biosensor (Responsible: UPB, ICECHIM)
Activity 2.4.1 Study of films reproducibility by morphological (SEM / microCT), structural (XPS / FTIR) characterization and contact angle measurements of hybrid films deposited on electrodes
Activity 2.4.2 Study of films reproducibility by specificity measurements for LPS (cyclic voltammetry) of hybrid films deposited on electrodes
Activity 2.5 Communication and dissemination of results through national or international conferences (Responsible: ICECHIM, EPI SISTEM)
Activity 2.5.1 Communication and dissemination activities of the results
Activity 2.5.2 Communication and dissemination activities of the results
In Stage II/2021, the 3D printing of hybrid films and their transposition on screen-printed electrodes is described. This main objective includes (i) Reproducibility of hybrid film preparation containing electroactive nanoparticles with printable paste and physico-chemical characterization (ii) Hybrid films printing by 3D technique on plain plastic or ceramic support and morpho-structural and thermal characterization (iii) Determination of specificity for LPS of hybrid films (static adsorption via UV-vis) (iv) Hybrid films printing by 3D technique on electrodes to obtain Hybrid Biosensors and physico-chemical characterization (v) electrochemical characterization of hybrid films for reproducibility by specificity measurements for LPS (cyclic voltammetry) of hybrid films deposited on electrodes.
ICECHIM coordinator has successfully prepared the precursor solutions for electroactive nanoparticle hybrid films (MIP-NPs) in printable paste form using as non-imprinted particles NIP VBTAC, NIP SDS, NIP CTAB and NIP BTAC and respectively imprinted particles with LPS, MIP VBTAC, MIP SDS, MIP
CTAB and MIP BTAC. Micro and nanoparticles were synthesized by sol-gel technique, using several stabilizers: benzyl triethylammonium chloride (BTAC), vinyl benzyl-trimethylammonium chloride (VBTAC), cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS). The electroactive hybrid pastes were subsequently printed by EPI-SISTEM partner on the working electrode surface of a screen-printed sensor (SPCE), thus obtaining the molecularly imprinted hybrid sensors with LPS, noted MIP-NPs-SPCE.
EPI-SISTEM S.R.L. Partner presents the tests regarding the hybrid films printing by 3D technique on plain plastic support. The films made by ICECHIM can be printed in good condition on various types of substrates and retain their electroactive properties after drying. The printing is done with nozzles with an inner diameter of 0.4 mm in conditions in which the shape quality of the electrodes is kept in good shape. Basic functionality is maintained and LPS detection is not affected. EPI SISTEM Partner prepared several sets of functionalized electrodes for LPS detection, namely it printed 40-50 electrodes,
10-15 pieces of each functionalization variant: MIP BTAC, MIP CTAB, NIP BTAC and NIP CTAB.
ICECHIM coordinator together with UPB Partner performed physico-chemical characterizations of hybrid films by FTIR spectroscopic analysis, contact angle measurements, BET porosimetry, morphological-dimensional SEM and DLS, thermal TGA / DTG, determination of LPS specificity of hybrid films by UV-Vis spectroscopy. Scanning electron microscopy (SEM) for sol-gel particles revealed relatively porous spherical particles, less regular, grouped in micro / nanosphere aggregates, ranging in size from a few hundred nanometers to a few microns, for both MIPs and NIPs. The variation of the contact angle depending on the time for the imprinted MIP BTAC and MIP CTAB hybrid pastes and the non-imprinted ones NIP BTAC and NIP CTAB, respectively, on plastic support, demonstrated a hydrophilic character. Dimensional characterization trough dynamic light diffusion analysis (DLS) technique of imprinted particles with LPS MIP and non-imprinted NIP, respectively, led to relatively stable dispersions, with the formation of aggregates and mostly single-mode distributions. The N2 adsorption-desorption isotherms of the imprinted, non-imprinted and extracted particle systems have been shown to be type II with a type IV allure according to IUPAC, with a hysteresis curve characteristic of mesoporous structures. The thermal decomposition mechanisms of the imprinted polymers differ from those of the non-imprinted polymers due to the LPS presence, with higher mass losses in the case of MIPs. Re-adsorption tests were performed to investigate the specificity of MIP particles for LPS by static adsorption via UV-vis. In the case of CTAB and BTAC polymers, the highest adsorption values were observed.
For the reproducibility of hybrid films, ICECHIM Coordinator together with UPB Partner performed physico-chemical characterizations of the hybrid films deposited on electrodes (biosensors) by FTIR spectroscopic analyzes, hybrid films contact angle measurements, SEM morphology of particles and biosensors, rheological characterization of hybrid films. FTIR analysis of the hybrid films deposited on the electrodes (MIP imprinted paste and NIP non-imprinted reference paste) confirmed the incorporation of MIP and NIP particles and zinc oxide in the polymer matrix as well as the presence of carbon paste. Rheological testing of MIP CTAB / NIP CTAB, MIP SDS / NIP SDS, MIP BTAC / NIP BTAC, MIP VBTAC / NIP VBTAC hybrid pastes and the reference paste led to a pseudo-plastic behavior with a Newtonian tendency to higher shear gradients of the reference paste similar to hybrid pastes with electroactive nanoparticles, which confirms the reproducibility of their optimal printing properties. The most efficient hybrid biosensors MIP/NIP BTAC-NPs-SPCE and MIP/NIP CTAB-NPs-SPCE were tested and characterized electrochemically by cyclic voltammetry to optimize the sensitivity for LPS. The electrochemical behavior of the MIP BTAC-NPs-SPCE and NIP BTAC-NPs-SPCE biosensors before and after the LPS addition, revealed that with the addition of LPS on the surface of the functionalized working electrode, the intensity of the oxidation current increases considerably due to a positive offset of the anodic peak potential.
In conclusion, hybrid biosensors both on ceramic substrate and printed on plastic support MIP/ NIP-NPs-SPCE electrochemically tested in the presence and absence of LPS template, proved to be reproducible, good results being obtained for both sensor systems based on of BTAC and CTAB.
1. Ana-Lorena Ciurlică, Ana-Mihaela Gavrilă, Catalin Zaharia, Ionut Cristian Radu, Bianca-Elena Stoica, Iulia Neblea, Andrei Sarbu, Horia Iovu, Tanta-Verona Iordache, Molecularly imprinted polymers for lipopolysaccharides recognition, Bucharest Polymer Conference (BPC), 2nd Edition, 9-11 June 2021, Bucharest, Romania (short oral communication)
2. Ana-Lorena NEAGU, Ana-Mihaela GAVRILA, Petru EPURE, Bianca-Elena STOICA, Iulia Elena NEBLEA, Catalin ZAHARIA, Horia IOVU, Tanta-Verona IORDACHE, Hybrid Inkjet-Pritable Paste for Screen-Printed Electrodes, Simpozion international Prioritatile Chimiei pentru o Dezvoltare Durabila PRIOCHEM – editia XVII, 27- 29 Octombrie 2021, Bucuresti, Romania (Poster)
3. Elena-Bianca STOICA, Iulia Elena NEBLEA, Elvira ALEXANDRESCU, Sabina Georgiana BURLACU, Catalin Ionut MIHAESCU, Andrei SARBU, Tanta-Verona IORDACHE, Ana-Mihaela GAVRILA, The development of a MIP-based sensor for electrochemical detection, International Scientific Conference “Applications of Chemistry in Nanosciences and Biomaterials Engineering -NanoBioMat 2021” for young researchers, 25-27 November 2021, Bucharest, Romania(oral communication)
4. 1st (June) and 2nd (December) Doctoral Reports, Ana-Lorena Ciurlica (Neagu) with the thesis title: BIOMIMETIC SENSORS OBTAINING BASED ON MOLECULAR IMPRINTED POLYMERS. Doctoral coordinator: Prof. Dr. Ing. Horia IOVU.
1. B.E. Stoica, A.M. Gavrila, A. Sarbu, H. Iovu, H. Brisset, A. Miron, T.V. Iordachec, Uncovering the behavior of screen-printed carbon electrodes modified with polymers molecularly imprinted with lipopolysaccharide, Electrochemistry Communications 124, 106965, 2021; https://doi.org/10.1016/j.elecom.2021.106965 Sended 2020, Published 2021
2. A.M. Gavrila, S. Nedelcu-Flor, A. Sarbu, T. Sandu, A. Olaru, G. Hubca, D. Donescu, T.V. Iordachec, Synthesis and properties of organosilica particles with quaternary ammonium bearings as bacteriostatic interfaces, Scientific Bulletin of UPB Series B, vol 3, 2021, Sended 2020, Published 2021
3. A.M. Gavrila , I.C. Radu, H. Stroescu, A. Zaharia, B.E. Stoica, A.L. Ciurlica, T.V. Iordachec, A. Sarbu, Role of functional monomers upon the properties of bisphenol A molecularly imprinted silica films, Applied Sciences 2021, 11(7), 2956; https://doi.org/10.3390/app11072956 Sended 2020, Published 2021
To support the activity of dissemination results, EPI SISTEM Partner has created a web page http://www.tehnoadvice.ro/toxinsens.htm where the summary of the 2021 stage will be presented.
PHASE III: DEVELOPING THE TECHNOLOGY FOR THE PREPARATION OF THE HYBRID BIOSENSOR AND DEMONSTRATION OF THE FUNCTIONALITY
PHASE PERIOD: 01.01-02.08.2022
Activity 3.1 Developing the technology for the preparation of Hybrid Biosensors (Responsible: P1, P2, CO)
Activity 3.1.1 Reproducibility of the preparation method for the precursor solutions of hybrid films (viscosity, structure) and reproducibility of the specificity and sensitivity of the biosensors (cyclic voltammetry) (CO)
Activity 3.1.2 Reproducibility of the printing method for films based on electroactive nanoparticles through the 3D technique on electrodes (P2)
Activity 3.1.3 Reproducibility of morphological (SEM/microCT) and structural (XPS/FTIR) characteristics of biosensors (P1)
Activity 3.2 – Demonstration of the functionality of the Hybrid Biosensor (Responsible: CO)
Activity 3.2.1 Establishing a reconditioning method for biosensors and demonstrating the versatility of hybrid biosensors for LPS fragments from various sources of pathogenic bacteria
Activity 3.3 Communication and dissemination of results through national or international conferences and journals indexed web of science (Responsible: CO, P2)
Activity 3.3.1 Communication and dissemination activities of the results
Activity 3.3.2 Communication and dissemination activities of the results
The research carried out in the Stage III describes (i) the reproducibility of the preparation method of the precursor solutions for the hybrid films improved with nano zinc oxide, (ii) the reproducibility of the specificity and sensitivity of the biosensors by cyclic voltammetry (CV) and pulse-differential voltammetry (DPV), (iii) the reproducibility of the method of printing films based on electroactive nanoparticles through the 3D technique on electrodes, (iv) the reproducibility of the morphological (SEM) and structural (FTIR) characteristics of the obtained biosensors, (v) Demonstration of the functionality of the hybrid biosensor for LPS from various sources of pathogenic bacteria (Escherichia Coli and Salmonella enterica).
ICECHIM coordinator prepared a series of polymer particles molecularly imprinted with LPS (MIP CTAB) and control non-imprinted NIP (NIP CTAB) through the sol-gel technique, in order to reproducibly prepare the precursor solutions. This system was selected due to its higher potential to detect LPS with sensitivity and specificity (according to the results of Stage II). The precursor solutions for hybrid films with electroactive nanoparticles in the form of hybrid paste were prepared using MIP/NIP CTAB and ZnO (nano) particles (20% solid powder and 80% carbon paste).
EPI SISTEM carried out activities related to the optimization of thin hybrid films based on carbon and silver inks useful for printing screen-printed electrodes sensitive to LPS and the primary evaluation of the electrochemical performances of the electrodes. The method used can be 100% inkjet for small series of electrodes and for medium and large series the hybrid method is recommended: screen printing and later inkjet.
ICECHIM coordinator together with the UPB Partner performed physico-chemical characterization of the hybrid films deposited on the electrodes (biosensors) through FTIR spectroscopic analyses, contact angle measurements, SEM morphology of biosensors, rheological characterization of the ZnO-based hybrid pastes (nano). In principle, the analysis carried out reveals both an improvement in the properties of the printed pastes/films, with the addition of ZnO (nano), but also a reproducibility of the important differences recorded between the pastes/films with MIP CTAB vs. NIP CTAB (as they were also registered in Stage II).
The CV and DPV experiments were carried out to study the analytical performance, namely the specificity and selectivity of the hybrid biosensors with the best results, e.g., MIP CTAB-Nano-SPCE and NIP CTAB-Nano-SPCE against LPS in the presence of LPS species such as LPS from Escherichia Coli and LPS from Salmonella enterica. The developed hybrid biosensor showed a strong electrochemical response to LPS from Pseudomonas Aeruginosa, indicating a good specificity of the developed CTAB-Nano-SPCE MIP. The performance of the hybrid biosensors led to excellent electrochemical properties, which allowed a low detection of LPS with a limit of detection (LOD) of only 0.28 μg/mL for the CTAB-Nano-SPCE MIP.
During Stage III/2022, in order to fulfil the deliverables from the implementation plan and to present the obtained results, the following dissemination actions were carried out: 1 published ISI article (2 articles in preparation) and 2 scientific communications at an international conference, updating the project web page. Within the framework of the current project, 1 Doctoral Scientific Report was drawn up and presented as part of a doctoral thesis in the field.
In order to support the activity of disseminating the results, the P2 EPI SISTEM has updated the project web page http://www.tehnoadvice.ro/toxinsens.html where the summary of the 2022 stage will also be presented.
1. Ana-Lorena Neagu, Bianca-Elena Stoica, Ana-Mihaela Gavrila, Andreea Miron, Sorin Dolana, Andrei Sarbu, Horia Iovu, Tanta-Verona Iordache, Molecularly imprinted surfaces doped with conductive polymers for Lipopolysaccharide recognition, Applications of Chemistry in Nanosciences and Biomaterials Engineering, NanoBioMat 2022 –Summer Edition, 22-24 Iunie 2022, poster.
2.Ana-Mihaela Gavrila, Ana-Lorena Neagu, Petru Epure, Anamaria Zaharia, Catalin Zaharia, Horia Iovu, Andrei Sarbu, Bianca-Elena Stoica, Sorin-Viorel Dolana, Tanta-Verona Iordache, Molecularly Imprinted Polymers for the Detection of Different Hazardous Analytes, 22nd Romanian International Conference on Chemistry and Chemical Engineering, Sinaia, ROMANIA – September 7 – 9, 2022 (accepted poster)
3. 3rd Doctoral Report (July), Ana-Lorena Ciurlica (Neagu) with the thesis title: BIOMIMETIC SENSORS OBTAINING BASED ON MOLECULAR IMPRINTED POLYMERS. Doctoral coordinator: Prof. Dr. Ing. Horia IOVU.
Bacterial pollution has become one of the crucial issues regarding food safety, the aquatic environment as well as drinking or domestic water sources. Bacteria lyse during and after death, releasing cell wall endotoxins in the original environment (water) where they can linger for a very long time. The most frequently reported bacterial endotoxins that appear in drinking water or in the intrahospital environment are lipopolysaccharides (LPS) produced by cyanobacteria and Gram-negative bacteria such as coliforms. The danger presented by these types of endotoxins consists in high resistance to temperature, to usual disinfectants and UV light. Therefore, a first step in preventing the contamination of environments with this type of endotoxins, and implicitly with pathogenic bacteria, is their on-site detection.
As a result, the 255PED/2020 TOXINSENS project was proposed in order to develop innovative, versatile and reusable biosensors for the rapid, qualitative and quantitative detection and monitoring of lipopolysaccharides (LPS – endotoxin derived from Gram-negative bacteria, GNB) in various biological samples, food or water. A biosensor is an analytical device, used for the detection of a chemical substance, which combines a biological component with a physical-chemical detector.
Figure 1. Screen-printed electrode model (screen-printed masks)
Figure 2. The surface of a screen-printed electrode visualized by scanning electron microscopy
In this sense, the project aimed at the following aspects: (i) the use of fundamental research notions acquired in previous projects for the development of specific receptors for LPS, (ii) the optimization of the preparation procedures for the recognition elements of the sensor, containing specific receptors for LPS, and (iii) establishing a suitable procedure for printing the recognition elements on plastic electrodes. These steps resulted in a new versatile biosensor for LPS detection, accompanied by a manufacturing technology brought to a higher level of technological maturity (laboratory technology). The demonstration study of the functionality and versatility of the biosensor was carried out using LPS from various pathogenic sources, such as Preudomonas Aeruginosa, Escherichia Coli and Salmonella Enterica.