Electrochemical Biomatrials Group

Department of Physical Chemistry and Electrochemistry
Faculty of Technology and Metallurgy
University of Belgrade

About us

The Electrochemical Biomatrials Group at the Department of Physical Chemistry and Electrochemistry, Faculty of Technology and Metallurgy, University of Belgrade, conducts research on electrochemical synthesis of antibacterial biomaterials for medical devices (hard and soft tissue implants, wound dressings). Research expertise includes electrochemical synthesis, electrophoretic deposition, bioceramic coatings, and synthesis of polymer composites with silver nanoparticles.

Research

A wide array of electrochemical methods can be utilized for the synthesis of different composite biomaterials, including:

  • Antibacterial bioceramic composite coatings on titanium for hard tissue implants
  • Antibacterial polymer composite hydrogels and films for wound dressings and soft tissue implants

Antibacterial bioceramic composite coatings on titanium for hard tissue implants

Numerous problems that occur during orthopedic interventions and implantation has led to increasing research interests in new hard tissue implant biomaterials, aimed to alleviate many issues associated with operative and post-operative complications in orthopedics. Titanium (Ti) is by far the most widely used metal for hard tissue implants due to its mechanical strength, stiffness, toughness, and low corrosion susceptibility. One of the most frequent issues is poor bio- and osseointegration of Ti, which is why its surface is usually modified by applying new, innovative bioactive coatings that provide strong support, improving the biomineralization process and reducing post-operation pain and infection risk. Hydroxyapatite (HAP,) a calcium phosphate mineral that has a structure similar to the natural bone usually represents a base of such materials. HAP-based coatings can be easily obtained on the titanium surface by powerful electrophoretic deposition (EPD). This method exhibits numerous advantages over the other existing coating methods: room temperature processing, single-step deposition of composite coatings from multicomponent deposition bath including HAP along with polymer components and antibacterial agents, coating deposition on inner or complex shape surfaces, control of coating thickness and morphology by changing the deposition parameters (applied voltage, deposition time) [1,2].

Lately, great attention has been paid to the antibacterial activity of these materials. Although much progress has been made in this field, bacterial infections remain a major problem to be addressed. An effective approach for the prevention of bacterial infections and biofilm formation can be achieved by the addition of various antibacterial agents, which would act locally at the site of implantation, without causing a cytotoxic effect. Also, in this way, a long-term controlled release of antibacterial agents at the desired location would be achieved.

Using single-step EPD at a constant voltage (Figure 1a) we have produced various HAP-based composite bioceramic coatings in combination with polymers (lignin, chitosan), graphene, and antibacterial agents (silver, gentamicin): HAP [3,5], HAP/graphene (HAP/Gr) [3], silver/HAP (Ag/HAP) [4], silver/HAP/graphene (Ag/HAP/Gr) [4], HAP/lignin (HAP/Lig) [5], silver/HAP/lignin (Ag/HAP/Lig) [5,6], HAP/chitosan (HAP/CS) [7], HAP/chitosan/graphene (HAP/CS/Gr) [7] coatings, deposited on Ti from ethanolic suspensions, and HAP/chitosan (HAP/CS) [8,10], HAP/chitosan/graphene (HAP/CS/Gr) [9], HAP/chitosan/gentamicin (HAP/CS/Gent) [8,10] and HAP/chitosan/graphene/gentamicin (HAP/CS/Gr/Gent) [9] coatings, deposited  on Ti from aqueous suspensions.

Detailed physicochemical characterization (X-ray diffraction, infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis) and electrochemical measurements (electrochemical impedance spectroscopy and potentiodynamic sweep measurements) of obtained composite coatings were performed to gain an insight into coatings’ morphology and structure, as well as their bioactive properties. High biomineralization ability was obtained for all the investigated coatings [4-7,10] except the pure HAP coating that lossеs its corrosion stability after just 24h [3]. Graphene addition reduced surface cracks and improved the thermal stability of HAP/Gr, Ag/HAP/Gr, and HAP/CS/Gr with respect to the graphene-free coatings, as a consequence of the toughening action of graphene [3,4]. The addition of lignin in composite Ag/HAP/Lig improved the coatings’ biocompatibility and served at the same time as a carrier for active component providing favorable slow and controlled silver release [5,6]. Chitosan addition improved the coatings’ adhesion to the substrate and provided a suitable platform for gentamicin loading [8-10]. Gentamicin release studies from HAP/CS/Gent and HAP/CS/Gr/Gent coatings exhibited a favorable “burst” release effect in the initial period that should prevent biofilm formation and ensure long-term protection from bacterial infections [8-10].

Strong antibacterial activity against Staphylococcus aureus (Figure 1b) and Escherichia coli bacterial strains was confirmed for Ag/HAP, Ag/HAP/Gr, Ag/HAP/Lig, HAP/CS/Gent and HAP/CS/Gr/Gent coatings. The biocompatibility of all investigated coatings towards human fibroblast cell line (MRC-5) and peripheral blood mononuclear cells (PBMC), as well as mouse  fibroblast cell line (L929), was proved using MTT test of cytotoxicity (Figure 1c).

Figure 1. (a) Scheme of electrophoretic deposition of composite coatings on Ti substrate; (b) antibacterial activity of HAP, Ag/HAP, HAP/Lig, Ag/HAP/Lig,  HAP/CS, HAP/CS/Gr, HAP/CS/Gent and HAP/CS/Gr/Gent coatings against S. aureus; (c) MRC-5, L929 and PBMC cell viability in the presence of HAP/CS, HAP/CS/Gr, HAP/CS/Gent, HAP/CS/Gr/Gent, Ag/HAP/Lig and Ag/HAP/Gr coatings.

References

[1] V. B. Mišković-Stanković, Electrophoretic Deposition of Ceramic Coatings on Metal Surfaces, in: Electrodeposition and Surface Finishing: Fundamentals and Applications, S. Djokić (Ed.), Modern Aspects of Electrochemistry, Vol. 57, Springer Science+Business Media, New York, USA, 2014: pp. 133-216.

[2] V. B. Mišković-Stanković, Biocompatible Hydroxyapatite-Based Composite Coatings Obtained by Electrophoretic Deposition for Medical Applications as Hard Tissue Implants, in: Biomedical and Pharmaceutical Applications of Electrochemistry, S. Djokić (Ed.), Modern Aspects of Electrochemistry, Vol. 60, Springer Science+Business Media, New York, USA, 2016: pp. 377-457.

[3] A. Janković, S. Eraković, M. Mitrić, I.Z. Matić, Z.D. Juranić, G.C.P. Tsui, C.Y. Tang, V. Mišković-Stanković, K.Y. Rhee, Journal of Alloys and Compounds 624 (2015) 148–157

[4] A. Janković, S. Eraković, M. Vukašinović-Sekulić, V. Mišković-Stanković, S.J. Park, K.Y. Rhee, Progress in Organic Coatings 83 (2015) 1-10

[5] S. Eraković, A. Janković, I.Z. Matić, Z.D. Juranić, M. Vukašinović-Sekulić, T. Stevanović, V. Mišković-Stanković, Materials Chemistry and Physics 142 (2013) 521-530

[6] S. Eraković, A. Janković, Dj. Veljović, E. Palcevskis, M. Mitrić, T. Stevanović, Dj. Janaćković, V. Mišković-Stanković, Journal of Physical Chemistry  B 117 (2013) 1633-1643.

[7] M. Đošić, S. Eraković, A. Janković,  M. Vukašinović-Sekulić, I.Z. Matić, J. Stojanović, K.Y. Rhee, V. Mišković-Stanković,  Journal of Industrial and Engineering Chemistry 47 (2017) 336-347

[8] M. Stevanović, M. Đošić, A. Janković, V. Kojić, M. Vukašinović-Sekulić, J. Stojanović, J. Odović, M. Crevar Sakač, K.Y. Rhee, V. Mišković-Stanković, ACS Biomaterials Science & Engineering 4 (2018), 3994-4007

[9] M. Stevanović, M. Djošić, A. Janković, V. Kojić, M. Vukašinović-Sekulić, J. Stojanović, J. Odović, M. Crevar Sakač, K.Y. Rhee, V. Mišković-Stanković, Journal of Biomedical Materials Research 108 (2020) 2175– 2189

[10] M. Stevanović, M. Djošić, A. Janković, K. Nešović, V. Kojić, J. Stojanović, S. Grujić, I. Matić Bujagić, K.Y. Rhee, V. Mišković-Stanković, ACS Omega 5 (2020) 15433–15445

Antibacterial polymer composite hydrogels and films for wound dressings and soft tissue implants

Local antibacterial agent application is usually more convenient than the systemic treatment, as it enables faster drug delivery to the (potential) infection site, while allowing the use of lower doses to achieve the same or stronger effect. A promising alternative to antibiotic treatments are silver nanoparticles (AgNPs), known for their broad-spectrum antibacterial activity and the fact that they do not provoke bacterial resistance in a way that antibiotics do. Electrochemical methods are efficient for in situ synthesis of AgNPs inside polymer matrices, with the main advantage being the complete absence of any chemical reducing agents that are often toxic and difficult to remove from the material. The electrochemical reduction of Ag+ ions is achieved only using electrical current or pure hydrogen gas that is generated at the cathode in aqueous electrolytes, which allows obtaining completely green and non-toxic product. Modifications in the synthesis process also enable the control of AgNPs properties, such as size and concentration.

One of the two main synthesis methods we have used for silver-loaded polymer composites production is galvanostatic (constant current density) AgNPs synthesis in polymer colloid solutions (Figure 2a), that can subsequently be further processed to obtain different shapes and forms (microbeads, films and hydrogels), e.g., Ag/alginate [11, 12], Ag/poly(vinyl alcohol) and Ag/poly(vinyl alcohol)/graphene [13,14]. The other highly efficient method is constant-voltage AgNPs synthesis in situ (Figure 2b) i.e., directly inside the cross linked hydrogel matrix. This method was utilized to obtain polymer hydrogels Ag/polyvinyl pyrrolidone (Ag/PVP) [15], Ag/poly(vinyl alcohol) (Ag/PVA) and Ag/poly(vinyl alcohol)/graphene (Ag/PVA/Gr) [16,17], Ag/poly(vinyl alcohol)/chitosan (Ag/PVA/CHI) (Figure 2c) and Ag/ poly(vinyl alcohol)/chitosan/graphene (Ag/PVA/CHI/Gr)[18-21].

The parameters of the both synthesis routes (duration, current density, voltage, precursor concentration) can be varied in order to control the obtained silver nanoparticles’ size, shape and concentration, enabling to fine-tune and maximize their antibacterial effect, as well as the other physicochemical and biological properties of the synthesized materials [22].

Physicochemical characterization of the obtained polymer composites with electrochemically synthesized silver nanoparticles was carried out using different techniques (UV-visible spectroscopy, infrared spectroscopy, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, atomic absorption spectroscopy) in order to investigate their structure, properties and morphology, as well as the AgNPs’ shape, dimensions, size distributions and release kinetics. Comparing different composites [23], it was found that the AgNPs sizes varied depending on the synthesis method and polymer materials compositions, e.g., the galvanostatically-synthesized AgNPs in Ag/PVA and Ag/PVA/Gr colloid dispersions were in the 10-40 nm range [14], whereas Ag/alginate colloids contained 10-30 nm sized AgNPs [11]. The smallest AgNPs with narrow size distributions were obtained by the in situ constant-voltage electrochemical synthesis in Ag/PVA/CHI and Ag/PVA/CHI/Gr hydrogels (2-11 nm) [18, 20], while it was found that chitosan content increase caused the formation of smaller AgNPs in higher concentration, which is definitely beneficial in terms of the heightened antibacterial activity of the obtained hydrogels. The addition of higher chitosan amounts in PVA-based hydrogels also caused better AgNPs stabilization, which was reflected in slower AgNPs release from Ag/PVA/CHI and Ag/PVA/CHI/Gr hydrogels, compared to Ag/PVP, Ag/PVA and Ag/PVA/Gr [23]. Silver release kinetics was also examined by fitting of the obtained experimental data using different theoretical kinetic and diffusion models (e.g., Korsmeyer-Peppas, Makoid-Banakar, Kopcha, and early time approximation models) that helped discern the diffusion-controlled mechanism of the silver release from the cross linked hydrogel matrices [18-20].

All of the above-mentioned silver loaded polymer composites exhibited excellent antibacterial activity against Staphylococcus aureus (Figure 2d) and Escherichia coli bacterial strains, whereas their biocompatibility and non-toxicity (Figure 2e) towards human fibroblast cell line (MRC-5) and peripheral blood mononuclear cells (PBMC) was proved using MTT test of cytotoxicity, confirming the strong potential of these novel materials for medical applications.

Figure 2. Electrochemical synthesis of silver nanoparticles in different polymer matrices: (a) galvanostatic method and (b) constant-voltage method; (c) AgNPs-loaded poly(vinyl alcohol)/chitosan hydrogels synthesized using the  constant-voltage method; (d) antibacterial activity of PVA, PVA/0.1CHI, PVA/0.5CHI, 0.25Ag/PVA/0.1CHI and 0.25Ag/PVA/0.5CHI hydrogels against S. aureus; (e) PBMC and MRC-5 cell viability in the presence of PVA, PVA/0.1CHI, PVA/0.5CHI, 0.25Ag/PVA/0.1CHI and 0.25Ag/PVA/0.5CHI hydrogels.

References

[11] Ž. Jovanović, J. Stojkovska, B. Obradović, V. Mišković-Stanković, Materials Chemistry and Physics 133 (2012), pp. 182-189

[12] J. Stojkovska, D. Kostić, Ž. Jovanović, M. Vukašinović-Sekulić, V. Mišković-Stanković, B. Obradović, Carbohydrate Polymers 111 (2014) 305-314

[13] R. Surudžić, A. Janković, M. Mitrić, I. Matić, Z. D. Juranić, Lj. Živković, V. Mišković-Stanković, K. Y. Rhee, S.J. Park, D. Hui, Journal of Industrial and Engineering Chemistry 34 (2016) 250-257

[14] R. Surudžić, A. Janković, N. Bibić, M. Vukašinović-Sekulić, A. Perić-Grujić, V. Mišković-Stanković, S.J. Park, K.Y. Rhee, Composites Part B: Engineering 85 (2016) 102-112

[15] Ž. Jovanović, A. Radosavljević, J. Stojkovska, B. Nikolić, B. Obradovic, Z. Kačarević‐Popović, V. Mišković‐Stanković, Polymer Composites  35 (2014) 217–226

[16] M. M. Abudabbus, I. Jevremović, K. Nešović, A. Perić-Grujić, K.Y. Rhee, V. Mišković-Stanković, Composites Part B: Engineering, 140 (2018) 99-107

[17] M.M. Abudabbus, I. Jevremović, A. Janković, A. Perić-Grujić, I. Matić, M. Vukašinović-Sekulić, D. Hui, K.Y. Rhee, V. Mišković-Stanković, Composites Part B: Engineering 104 (2016) 26-34

[18] K. Nešović, A. Janković, A. Perić-Grujić, M. Vukašinović-Sekulić, T. Radetić, Lj. Živković, S.J. Park, K.Y. Rhee, V. Mišković-Stanković, Journal of Industrial and Engineering Chemistry 77 (2019) 83-96

[19] K. Nešović, A. Janković, V. Kojić, M. Vukašinović-Sekulić, A. Perić-Grujić, K.Y. Rhee, V. Mišković-Stanković, Composites Part B: Engineering 154 (2018) 175-185

[20] K. Nešović, A. Janković, T. Radetić, M. Vukašinović-Sekulić, V. Kojić, Lj. Živković, A. Perić-Grujić, K.Y. Rhee, V. Mišković-Stanković, European Polymer Journal 121 (2019) 109257

[21] K. Nešović, V. Kojić, K.Y. Rhee, V. Mišković-Stanković, Corrosion 73 (2017) 1437-1447

[22] V. B. Mišković-Stanković, Electrochemical Production of Polymer Hydrogels with Silver Nanoparticles for Medical Applications as Wound Dressings and Soft Tissue Implants, in: Biomedical and Pharmaceutical Applications of Electrochemistry, S. Djokic (Ed.), Modern Aspects of Electrochemistry, Vol. 60, Springer Science+Business Media, New York, USA, 2016, pp. 267–375

[23] K. Nešović, V. Mišković‐Stanković, Polymer Engineering and Science 60 (2020) 1393-1419

New references related to the project

Papers in SCI journals:
  1. Tijuana Lužajić Božinovski, Vera Todorović, Ivan Milošević, Vladimir Gajdov, Bogomir Bolka Prokić, Katarina Nešović, Vesna Mišković-Stanković, Danica Marković, Evaluation of soft tissue regenerative process  after subcutaneous implantation of silver/poly(vinyl alcohol) and novel silver/poly(vinyl alcohol)/graphene hydrogels in an animal model, Acta Veterinaria-Beograd71, 3, (2021) 285-302. DOI: 10.2478/acve-2021-0025. (Veterinary Sciences) =
  2. Tijana Lužajić Božinovski, Vera Todorović, Ivan Milošević, Bogomir Bolka Prokić, Vladimir Gajdov, Katarina Nešović, Vesna Mišković-Stanković, Danica Marković, Macrophages, the main marker in biocompatibility evaluation of new hydrogels after subcutaneous implantation in rats, J. Biomater. Appl., 36, 6 (2022) 1111–1125. DOI: 10.1177/08853282211046119. (Biomedical Engineering) =
  3. Marija Djošić, Ana Janković, Vesna Mišković-Stanković. Electrophoretic Deposition of Biocompatible and Bioactive Hydroxyapatite-Based Coatings on Titanium, Materials, 14, 18, (2021) 5391. https://doi.org/10.3390/ma14185391, (Materials Science – Invited by Guest Editor M. Gasik) =
  4. Milena Stevanović, Marija Djošić, Ana Janković, Vesna Kojić, Jovica Stojanović, Svetlana Grujić, Ivana Matić Bujagić, Kyong Yop Rhee, Vesna Mišković-Stanković, The Chitosan-Based Bioactive Composite Coating on Titanium, J. Mater. Res. Technol.15 (2021) 4461-4474. https://doi.org/10.1016/j.jmrt.2021.10.072, (Materials Science) =
  5. Katarina Nešović, Vesna Mišković-Stanković, Silver/poly(vinyl alcohol)/graphene hydrogels aimed for wound dressing applications: understanding the mechanism of silver release, J. Vinyl and Additive Technology, (2021), https://doi.org/10.1002/vnl.21882, (Materials Science) =
Invitation lecture:
  1. Vesna Mišković-Stanković, Antibacterial hydroxyapatite/chitosan/gentamicin composite coatings, ECI Webinar Electrophoretic Deposition: Fundamentals and Applications, 17th Novembar 2021.
International conferences:
  1. Katarina Nešović, Ana Janković, Rade Surudžić, Maja Vukašinović-Sekulić, Vesna Kojić, Tamara Radetić, Vesna Mišković-Stanković, Silver Nanoparticles-Loaded Poly(vinyl alcohol)/Chitosan/Graphene Hydrogels Obtained by Electrochemical Synthesis, TERMIS 2021, Maastricht, The Netherlands, 15-19 November 2021, Abs. No. 480. =
  2. Milena Stevanović, Marija Djošić, Ana Janković, Katarina Nešović, Vesna Mišković-Stanković, Graphene-Loaded Bioactive Hydroxyapatite Coatings on Titanium Substrate – Fundamental In Vitro Investigations, TERMIS 2021, Maastricht, The Netherlands, 15-19 November 2021, Abs.No. 482. =
  3. Bojana Obradovic, Jasmina Stojkovska, Jovana Zvicer, Ivana Banicevic, Ana Medic, Sasa Novak, Djordje Veljovic, Vesna Miskovic Stankovic, Physiologically relevant assessment of biomaterials in biomimetic bioreactors aimed for regeneration of skeletal tissues, TERMIS 2021, Maastricht, The Netherlands, 15-19 November, 2021 (online), Abstract Book online, Abstract #1530. = Page 1305.
  4. Nevena Jaćimović, Marija Đošić, Ana Janković, Vesna Mišković – Stanković, Electrochemical composite bioceramic coatings based on hydroxyapatite, chitosan and polyvinyl alcohol loaded with gentamicin, Nineteenth Young Researchers’ Conference – Materials Sciences and Engineering, Serbian Academy of Sciences and Arts,  Belgrade, Serbia, December 1-3. 2021, Programme and the Book of Abstracts, 2-2, p. 7. = Page 27.
  5. Marko Opsenica, Katarina Nešović, Vesna Mišković-Stanković, Electrochemical synthesis of silver nanoparticles in poly(vinyl alcohol)-based hydrogels and evaluation of their sizes by comparing experimental and simulated UV-visible spectra, Nineteenth Young Researchers’ Conference – Materials Sciences and Engineering, Serbian Academy of Sciences and Arts,  Belgrade, Serbia, December 1-3. 2021, Programme and the Book of Abstracts, 6-2, p. 30. = Page 50.
National conferences:
  1. Sofija Petković, Katarina Nešović, Ana Janković, Aleksandra Perić-Grujić, Maja Vukašinović-Sekulić, Vesna Kojić, Vesna Mišković-Stanković, Electrochemical synthesis of silver nanoparticles in poly(vinyl alcohol) and alginate hydrogels, 57th Meeting of the Serbian Chemical Society, Kragujevac, Serbia, June 18-19, 2021 (Online), Book of Abstracts, EH-P-7, p. 44. =
  2. Marko Opsenica, Katarina Nešović, Vesna Mišković-Stanković, Optimization of electrochemical synthesis of silver nanoparticles in poly(vinyl alcohol)/chitosan hydrogels using experimental and simulated UV-visible spectra, 57th Meeting of the Serbian Chemical Society, Kragujevac, Serbia, June 18-19, 2021 (Online), Book of Abstracts, EH-P-8, p. 45. =
  3. Ana Janković, Milena Stevanović, Marija Đošić, Maja Vukašinović-Sekulić, Vesna Kojić, Svetlana Grujić, Ivana Matić-Bujagić, Vesna Mišković-Stanković, Bioactive Gentamicin-Eluting Composite Coatings on Titanium, 57th Meeting of the Serbian Chemical Society, Kragujevac, Serbia, June 18-19, 2021 (Online), Book of Abstracts, EH-P-9, p. 46. =
  4. Nevena Jaćimović, Marija Đošić, Ana Janković, Vesna Mišković-Stanković, Electrochemical hydroxyapatite, chitosan and polyvinyl alcohol bioceramic coatings, VeryYOUngResearcher’S Conference 2021VeryYOURS, Zlatibor, 4-7. July, 2021, p. 7.
Awards:
  1. Sofija Petković, Katarina Nešović, Ana Janković, Aleksandra Perić-Grujić, Maja Vukašinović-Sekulić, Vesna Kojić, Vesna Mišković-Stanković, Electrochemical synthesis of silver nanoparticles in poly(vinyl alcohol) and alginate hydrogels, IUPAC Poster Prize, 57th Meeting of the Serbian Chemical Society, Kragujevac, Serbia, 18-19 June 2021. =
  2. Veljović Đorđe, Đošić Marija, Zvicer Jovana, Zebić Maja, Janaćković Đorđe, Janković Ana, Matić Tamara, Miletić Vesna, Nešović Katarina, Obradović Bojana, Osmokrović Andrea, Petrović Rada, Mišković Stanković Vesna, Stevanović Milena i Stojkovska Jasmina, “Novi multifunkcionalni biomaterijali za primenu u medicine “,  Zlatna medalja, Međunarodni festival inovacija, znanja i stvaralaštva TESLA FEST 2021, Savez pronalazača Vojvodine, Novi Sad, 12-15. oktobar, 2021, Katalog, p. 5. =

Contact

Prof. Dr. Vesna Mišković Stanković, Head of the laboratory, e-mail: vesna@tmf.bg.ac.rs