scholarly journals Mechanical Characterization of Human Trabecular and Formed Granulate Bone Cylinders Processed by High Hydrostatic Pressure

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1069
Author(s):  
Janine Waletzko-Hellwig ◽  
Michael Saemann ◽  
Marko Schulze ◽  
Bernhard Frerich ◽  
Rainer Bader ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Bone Substitutes ◽  
Biomechanical Properties ◽  
Negative Effects ◽  
Suitable Alternative ◽  
Allogenic Bone ◽  
Bone Substitute Materials ◽  
Processing Techniques

One main disadvantage of commercially available allogenic bone substitute materials is the altered mechanical behavior due to applied material processing, including sterilization methods like thermal processing or gamma irradiation. The use of high hydrostatic pressure (HHP) might be a gentle alternative to avoid mechanical alteration. Therefore, we compressed ground trabecular human bone to granules and, afterwards, treated them with 250 and 300 MPa for 20 and 30 min respectively. We characterized the formed bone granule cylinders (BGC) with respect to their biomechanical properties by evaluating stiffness and stress at 15% strain. Furthermore, the stiffness and yield strength of HHP-treated and native human trabecular bone cylinders (TBC) as control were evaluated. The mechanical properties of native vs. HHP-treated TBCs as well as HHP-treated vs. untreated BGCs did not differ, independent of the applied HHP magnitude and duration. Our study suggests HHP treatment as a suitable alternative to current processing techniques for allogenic bone substitutes since no negative effects on mechanical properties occurred.

scholarly journals Potato Starch Hydrogels Produced by High Hydrostatic Pressure (HHP): A First Approach

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1673 ◽  
Author(s):  
Dominique Larrea-Wachtendorff ◽  
Gipsy Tabilo-Munizaga ◽  
Giovanna Ferrari
Keyword(s):  
Mechanical Properties ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Potato Starch ◽  
Water Concentration ◽  
Medium Size ◽  
Processing Temperature ◽  
Processing Conditions ◽  
Scanning Calorimetry ◽  
Absorption Bands

Starch-based hydrogels have received considerable interest due to their safe nature, biodegradability and biocompatibility. The aim of this study was to verify the possibility of producing natural hydrogels based on potato starch by high hydrostatic pressure (HHP), identifying suitable processing conditions allowing to obtain stable hydrogels, as well as to characterize structural and mechanical properties of these products. Sieved (small size granules and medium size granules) and unsieved potato starch samples were used to prepare aqueous suspensions of different concentrations (10–30% w/w) which were processed at 600 MPa for 15 min at different temperatures (25, 40 and 50 °C). Products obtained were characterized by different techniques (light and polarized microscopy, Fourier transform infrared spectroscopy (FTIR), rheology and differential scanning calorimetry (DSC)). Results obtained so far demonstrated that potato starch suspensions (20% starch–water concentration (w/w)) with granules mean size smaller than 25 µm treated at 600 MPa for 15 min and 50 °C showed a complete gelatinization and gel-like appearance. Potato HHP hydrogels were characterized by high viscosity, shear-thinning behavior and a highly structured profile (G’ >> G’’). Moreover, their FTIR spectra, similarly to FTIR profiles of thermal gels, presented three absorption bands in the characteristic starch-gel region (950–1200 cm−1), whose intensity increased with decreasing the particle size and increasing the processing temperature. In conclusion, potato starch hydrogels produced by HHP in well-defined processing conditions exhibited excellent mechanical properties, which can be tailored according to the requirements of the different applications envisaged.

scholarly journals Effect of High Hydrostatic Pressure on Human Trabecular Bone Regarding Cell Death and Matrix Integrity

2021 ◽  
Vol 9 ◽  
Author(s):  
Janine Waletzko-Hellwig ◽  
Christopher Pohl ◽  
Janik Riese ◽  
Michael Schlosser ◽  
Michael Dau ◽  
...  
Keyword(s):  
Cell Death ◽  
Hydrostatic Pressure ◽  
Trabecular Bone ◽  
High Hydrostatic Pressure ◽  
Biological Effects ◽  
Donor Site ◽  
Biomechanical Properties ◽  
Point Analysis ◽  
Physical Processing ◽  
Biological Methods

The reconstruction of critical size bone defects is still clinically challenging. Even though the transplantation of autologous bone is used as gold standard, this therapy is accompanied by donor site morbidities as well as tissue limitations. The alternatively used allografts, which are devitalized due to thermal, chemical or physical processing, often lose their matrix integrity and have diminished biomechanical properties. High Hydrostatic Pressure (HHP) may represent a gentle alternative to already existing methods since HHP treated human osteoblasts undergo cell death and HHP treated bone cylinders maintain their mechanical properties. The aim of this study was to determine the biological effects caused by HHP treatment regarding protein/matrix integrity and type of cell death in trabecular bone cylinders. Therefore, different pressure protocols (250 and 300 MPa for 10, 20 and 30 min) and end point analysis such as quantification of DNA-fragmentation, gene expression, SDS-PAGE, FESEM analysis and histological staining were performed. While both protein and matrix integrity was preserved, molecular biological methods showed an apoptotic differentiation of cell death for lower pressures and shorter applications (250 MPa for 10 and 20 min) and necrotic differentiation for higher pressures and longer applications (300 MPa for 30 min). This study serves as a basis for further investigation as it shows that HHP successfully devitalizes trabecular bone cylinders.

The Effect of High Hydrostatic Pressure on the Mechanical Properties of the Surface of the Sea-Urchin Egg

1971 ◽  
Vol 8 (1) ◽  
pp. 87-92
Author(s):  
L. WOLPERT ◽  
D. MARSLAND ◽  
M. HIRSHFIELD
Keyword(s):  
Mechanical Properties ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Significant Contribution ◽  
Cell Diameter ◽  
Urea Treatment ◽  
Plastic Sheet ◽  
Sea Urchin Egg ◽  
Resistance To Deformation ◽  
Fertilization Membrane

There is evidence that high hydrostatic pressure can solate and weaken gel-like structures within cells. It was thus of interest to determine its effect on the mechanical properties of the cell surface since it has been suggested that there is a gel-like cortex beneath the plasma membrane which makes a significant contribution to its mechanical properties. The mechanical property measured was the resistance to deformation when the eggs were compressed mechanically. The eggs of Arbacia were compressed by placing a small plate made either from a fragment of coverslip or Melinex plastic sheet on a small group of eggs (20-100) so that the eggs supported the plate. The deformation of the eggs was determined by measuring their increased diameter. The mechanical properties of the cell membrane of unfertilized eggs appear to be unaffected by high hydrostatic pressure. When compressed fertilized eggs, from which the fertilization membrane had been, removed by urea treatment, were subjected to pressure of about 7x104 kN m-2 (10000 lb/in.2) there was a significant increase in cell diameter. This increase was such that it appeared as if the resistance to deformation of the membrane were about quartered. Surprisingly after a few minutes the diameter decreased again indicating a contraction at the membrane even while under high hydrostatic pressure. Release of the hydrostatic pressure resulted in a further reduction in diameter and thus contraction at the surface, the final diameter sometimes being less than that before the hydrostatic pressure was applied.

Viability of sous vide, microwave and high pressure processing techniques on quality changes during shelf life of fresh cowpea puree

2020 ◽  
Vol 26 (8) ◽  
pp. 706-714 ◽  
Author(s):  
Tâmmila Venzke Klug ◽  
Elena Collado ◽  
Ascensión Martínez-Sánchez ◽  
Perla A Gómez ◽  
Encarna Aguayo ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Microwave Treatment ◽  
High Pressure Processing ◽  
Total Phenolic ◽  
Quality Changes ◽  
High Hydrostatic Pressure Processing ◽  
Viscoelastic Parameters ◽  
Sous Vide ◽  
Processing Techniques

An innovative cowpea puree containing 78.8% of fresh cowpea seeds was developed. Microwave treatment (8 kW/35 s), high hydrostatic pressure (550 MPa/10 min/23 ℃) or sous vide treatment (80 ℃, 3 min) were assayed as processing techniques. Blended fresh cowpea samples were used as control. Quality changes during 21 days at 5 ℃ were studied. Sous vide samples showed a relevant loss during storage of viscoelastic parameters, like elastic modulus (G′) and viscous modulus (G″), which was also perceived in the sensory evaluation. On the contrary, high hydrostatic pressure and microwave treatments were able to preserve consistency, texture and taste. However, physicochemical properties, mainly colour, were greatly influenced by thermal treatments, although high hydrostatic pressure treatment preserved greenness. Total phenolic content and total antioxidant capacity were more affected by high hydrostatic pressure than by microwave treatments. In conclusion, microwave and high hydrostatic pressure processing treatments seem to be quite interesting techniques to develop legume-based products.

High Hydrostatic Pressure as a Method to Reduce Microbial Contamination of Porcine Blood Plasma

2001 ◽  
Vol 7 (2) ◽  
pp. 117-121 ◽  
Author(s):  
D. Pares ◽  
E. Saguer ◽  
M. Toldra ◽  
C. Carretero
Keyword(s):  
Hydrostatic Pressure ◽  
Blood Plasma ◽  
Functional Properties ◽  
High Hydrostatic Pressure ◽  
Microbial Contamination ◽  
Processing Temperature ◽  
Negative Effects ◽  
Efficient Treatment ◽  
Porcine Blood ◽  
Microbial Stability

The suitability of high hydrostatic pressure as an alternative method to produce porcine blood plasma with a sufficient microbial stability without affecting its functional properties was evaluated. The effects of high pressure on plasma microorganisms were highly dependent on processing temperature. Treatments of 15 min at 450 MPa carried out at 5 'C led to reductions of about 90% in microbial counts and to 20-50% decreases in the growth ability of the survivors. At 25 'C and 40 'C, the efficiency was increased to reduction values of 99.82 and 99.97%, respectively. The lowering of the growth capacity was about 50% at 25 'C and up to 80% at 40 'C. The most efficient treatment (450 MPa, for 15 min at 40 'C) did not lead to appreciable negative effects on the functional properties of heat-induced gels from porcine blood plasma.

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