RESEARCH AND DEVELOPMENT

Prosilas in the Biomedical sector


Prosilas believes in the research and actively participate in different projects that can revolutionize current applications in the biomedical sector in the near future.

One of this study, carried out with the participation of the Modena University, Marche Polytechnic University, Paiva University and Turin Polytechnic, led to the creation of platforms (scaffold) for the increase of stem cells.

On the basis of this project, the research of a student of the University of Pavia has come to life, Dr. Maria Laura Gatto, who conceived and designed geometric structures that would allow controlled proliferation of cells.

The materials chosen for the realization of the scaffolds were Polycaprolaxtone(PCL) and Hydroxyapatite: these materials, in the microscopic matrix, simulate the structure of the human bone allowing not only the survival of the injected cells, but also allowing their reproduction.

Prosilas has developed its own know-how inherent in the processing of innovative polymers through internal testing, and has succeeded in producing these structures through Selective Laser Sintering (SLS) by changing the working parameters of the machineries. It was thus possible to process biocompatible and bio-resorbable materials.

The results achieved were very positive: the cell viability has reached values well above respect to what it was initially expected.

The success of this innovative technique opens new way: for example, it will be possible to regenerate organs and muscle tissues removed after invasive operations and it will also be possible to rebuilt bone elements.

Dr. Maria Laura Gatto is now continuing with her studies on the subject during her PhD and Prosilas will continue to support her in her experiments.

Further developments are planned in the next months, and all the updated data will be share as soon as they will be available.

Case Study

Adhesive process of human MSC on PCL scaffold: 70/HA: 30 products for Selective Laser Sintering with EOS P396

The project focuses on the assessment of the adhesion of human mesenchymal stem cells (hMSC) on PCL scaffolds: 70/HA:30 products with the Powder Bed Fusion technique using Selective Laser Sintering with EOS P396. Mechanical tests on the scaffolds have demonstrated characteristics comparable to those of the bone. The surface and shape of the scaffolds were observed under the optical microscope (LM) and the scanning electron microscope (SEM), while the surface roughness was measured by confocal microscopy. The 24-hour and 4-day viability tests of the seeded cells were carried out by in vitro Alamar Blue (AB) tests. The actual cell presence with SEM acquisitions was therefore proven.

THE TISSUE ENGINEERING

In the tissue engineering field, the regenerative medicine, in particular of bone tissue, proposes the use of structures engineered in innovative materials produced through Additive Manufacturing technologies, scaffolds, where tissue regeneration is not sufficient and bone grafts are choices with less than optimal ethical and clinical implications. The hMSCs raised by the patient, in fact, if equipped with an environment that simulates the original growth environment, will evolve into fabrics that resemble native structures.

SCAFFOLD OPERATIONS (LM AND SEM)

From observation with a 3D optical microscope, the geometries are inaccurate and irregular, in particular the porosity changes shape. A difficulty in spreading and sintering the powders by means of a laser beam is also noteworthy: in fact there are in large quantities partially melted or agglomerated particles, observable with SEM.

MECHANICAL COMPRESSION TESTS ON SCAFFOLD

Scaffolds show repetitiveness of behaviour, with nominal loads that are positioned in the lower limit of the mechanical behaviour range of the bones (between 5 MPa for the lumbar vertebra and 167 MPa for the femur).
In fact, considering the mechanical performance of the scaffolds at 40% of the initial height value, the loads are between 100 N and 300 N, which correspond to nominal values between 1 MPa and 3 MPa.

ROUGHNESS MEASURES ON SCAFFOLD

The difference in roughness between the two geometries is not significant. The RD3 geometry, however, has values relating to the height of the peaks, the depth of the valleys and the asymmetries between them with respect to the greater median plane.
This is due to the difficulty of sintering the PCL powders, irregular and not homogeneous; effect partially attenuated by the presence of HA.

OBSERVATIONS CELLS 24 H (SEM)

In ordert to confirm the 24-hour vitality data, SEM observations of the samples were carried out. In all, it is clear the presence of spreading cells, that is the intracellulare anchorages of the cytoskeleton which allow the cell membrane to extend forming some protuberances to adhere to the surface of the material.

24-HOUR VITALITY DATA WITH AB

Data are normalised respect to the number of stem cells (50,000 per sample) and are expressed in percentage. It is evident that the control has absolute vitality values at 24 hours, while at 4 days the data become comparable with those of the scaffolds. RD3 geometry appears to prefer the vitality compared to d-20, with a confirmed trend both at 24 hours and at 4 days, probably due to pore control issues.
For the fact that Hmsc has a 40-hours cell cycle, in 4 days the number of cells is approximately doubled.