Title Development of a module for 3D printing of biologically complex structures used in regenerative medicine
Area Slovenian Smart Specialization Strategy (S4): Technologies / Materials as finished products
Presentation illustration
Duration 1. 4. 2019 – 31. 3. 2022
Funding 171.684,00 EUR
Project head Dr. Yasir Beeran Potta Thara https://cris.cobiss.net/ecris/si/sl/researcher/49439
Participating organizations IRNAS – Inštitut za razvoj naprednih aplikativnih sistemov, d.o.o.
https://www.irnas.eu/ https://cris.cobiss.net/ecris/si/sl/organization/7713
Objectives The preparation of tissue substitutes or their regeneration is still problematic due to complex shapes and material requirements. 3D printing allows the production of materials that can not only be designed to suit the patient, but also be adapted to the compatibility requirements. 3D printing also enables the production of materials that morphologically and histologically suit the patient. A major challenge remains still in the fabrication of structures from biological and biocompatible materials with sufficiently large and gradient porosity and at the same time good enough mechanical stability. The aim of this project was thus to develop a cryo-module that would enable more controlled production of porous materials (scaffolds) with Vitaprint 3D bioprinter (IRNAS d.o.o.) from hydrogels, in a combination with other organic and inorganic components, suitable for the regeneration of hard / bone or soft tissues.
Specific Work packages (WPs) WP 1 MODULE DEVELOPMENT (0-18 months)

To design and manufacture a cooling module for one-way cooling of the material, which will control the cooling rate and temperature of samples, thus influencing the organization of solvent crystals (e.g. water) in the injected polymer solution and their redistribution. The following activities have been performed:
Act. 1.1 Module design, Act. 1.2 Definition of boundary conditions, Act. 1.3 Mechanization prototyping and platform compatibility with Vitaprint 3D bioprinter, Act. 1.4 Testing of cooling with gelatin solution, determination of thermophysical properties and simulation of plate cooling.

Results: Successfully developed innovative prototype cooling module.

Schematic representation of a) the experimental setup and b) the corresponding digital image of the setup, c) the cryo-platform with 3D-printed petri dish and thermocouple holder, and d) the cooling assembly of the platform.


POTTA THARA, Yasir Beeran, KOKOL, Vanja. Optimization of a cooling platform for the stabilization of gelatin hydrogel deposition during 3D-bioprinting. V: Proceedings on 4th International Conference on Biomaterials, Cellular and Tissue Engineering ; 5th International Conference on Nano Medicine and Nano Technology ; 9th Annual Congress on Advanced Materials and Nano Science : Oct. 14, 2020, webinar. Welling (UK): Allied Academies, 2020.

POTTA THARA, Yasir Beeran, JORDAN, Miha, GOMBOC, Timi, KAMENIK, Blaž, VIHAR, Bostjan , KOKOL, Vanja, ZADRAVEC, Matej. Solidification of gelatine hydrogels by using a cryo-platform and its validation through CFD approaches. Submitted to Gels, MDPI.


Act 2.1 Rheological studies of gelling / solidification of differently concentrated gelatin solutions induced by horizontal freezing and flow / injection for implementation, Act 2.2 Study of implant production (3D porous specimens) with differently formulated collagen-hydroxyapaptite materials by freezing, Act 2.3 Determination of biocompatibility (cellular analysis) of manufactured samples.

Results: Successfully validated prototype cooling module for Vitaprint.

Digital images of 3D bioprinting experiments with Vitaprint: (a and b) printing of an ear model using starch, printing of gelatin scaffolds using (c and d) at room temperature, (e) at a temperature of -10 °C on a glass Petridis, and (f) at a temperature of -20 °C on a thermal cooling module.


KOKOL, Vanja, POTTA THARA, Yasir Beeran, MIHELČIČ, Mohor, SLEMENIK PERŠE, Lidija. Rheological properties of gelatine hydrogels affected by flow- and horizontally-induced cooling rates during 3D cryo-printing. Colloids and surfaces. A, Physicochemical and Engineering Aspects. 2021, vol. 616 (126356), pp 1-10, DOI: 10.1016/j.colsurfa.2021.126356.

POTTA THARA, Yasir Beeran, VUHERER, Tomaž, MAVER, Uroš, KOKOL, Vanja. Morphological, mechanical, and in-vitro bioactivity of gelatine/collagen/hydroxyapatite based scaffolds prepared by unidirectional freeze-casting. Polymer testing. 2021, vol. 102 (107308), pp 1-13. DOI: 10.1016/j.polymertesting.2021.107308.


Act 3.1 Optimization of 3D printing experiments of gel solutions using Vitaprint and cryo-plate
Act 3.2 Determination of limit values of 3D printing using cryo-module (maximum carrier height / number of layers, porous structure, storage / lyophilization)
Act 3.3 Characterization of 3D printed models (topology, internal and external surface morphology, porosity, interoperability, pore surface; stability under cell culture conditions, physico-mechanical, compression and viscoelastic properties in in-vivo conditions).

Results: Scientific articles on understanding the production of 3D scaffolds using different printing protocols and using different bioink formulations. Publications in progress.

Effect of nozzle diameter on the morphology of 3D printed scaffolds a) from gelatin/collagen/hydroxyapatite at room temperature, and gelatin at 0°C using 21G nozzle.