This research work focuses on the fabrication and study of a series of nanocomposites consisting of two types of hydroxyapatite (HA), obtained by precipitate (HAP) and sol–gel (HAG) methods, and a boro-silico-phosphate bioglass. The microstructure and chemical, mechanical, and biological properties as functions of three factors, namely (i) the type of hydroxyapatite, (ii) glass content, and (iii) sintering temperature, were investigated. It was found that all of these factors affect the final composition and microstructure, especially, porosity, which shows significantly lower values for HAP-based composites than for HAG-based ones and higher values for higher glass content. This, in turn, has an impact on the microhardness, which exhibits a strong correlation with porosity, as well as on the mineralization capability and cell viability due to the different dissolution rate.

Cancer is a global medical problem and, despite research efforts in the field of tumor treatment, there is currently a shortage of specific anticancer drugs. Most anticancer drugs show significant side effects. The liver is the organ that has central functions in drug metabolism, being a major target of the harmful action of anticancer compounds. In this context, it is essential to evaluate the cytotoxic effects of potential anticancer substances. Therefore, hepatotoxicity and hepatocyte viability were determined in vitro to evaluate the action of seven new local thiosemicarbazide coordination compounds (CCT) on normal liver cells. Doxorubicin was used as a reference substance. The control group consisted of hepatocytes not exposed to CCT action. The cell viability of hepatocytes treated with CCT decreased significantly by 5–12% compared to the control, but was statistically significantly higher by 5–14% compared to doxorubicin, except after CMD-8 and CMT-67 influence, when it does not change. Thus, new local CCT had a selective effect on hepatocytes in vitro and were less hepatotoxic compared to doxorubicin, which may be the basis for further study of its potential in anticancer drugs.

Background: Articular cartilage has poor regenerative capacities. Numerous cartilage repair techniques are known, including implantation of autologous chondrocytes. Material and methods: From 18 rabbits pieces of cartilage were harvested from femoral condyle. Minced cartilage was treated with 0.25% trypsin-EDTA. In the 1st group (n=9) the cartilage was digested with 0.6% collagenase in 15 ml tubes by shaking in incubator at 37°C, 5%CO2 . In the 2nd group (n=9) digestion was performed in 25cm2 cell culture flasks placed on the lateral side, monitoring the process under a microscope after 120 minutes. The isolated cells were cultured to a 80-90% confluence. The chondrocytes were identified using histochemical staining after culturing for 16 days in overconfluence. Results: Chondrocytes isolation in the 1st group lasted a fixed 360 minutes, in the 2nd group – 140±10 minutes. In the 1stgroup were isolated 9.2x104 ±3.1x104 chondrocytes with a viability of 85.36±16.41%, but in the 2nd group – 1.6x105 ±3.4x104 chondrocytes with a viability of 98.09±3.85%. The mean period of cell culture in the 1st group was 15±2 days, in the 2nd group – 11±3 days. In first passage of the 1st group were obtained – 1.2x106 ±4.3x105 chondrocytes and in the 2nd group – 2.92x106 ±3.6x105 chondrocytes. The secreted extracellular matrix by chondrocytes was stained specifically for cartilaginous tissue. Conclusions: The method used for chondrocytes isolation has a direct impact on the number of isolated cells, their viability, but also upon the culture period and the number of cells obtained during the first passage.

The research aims to present an improved cellularization process of small sized grafts obtained from biological materials through utilisation of gravitational modality principle. The obvious problem of the biological materials cellularization process, is failure in instant absorption of poured cellular suspension, as a result it leads to cells loss because of suspension spreading through the used dishes, which is especially characteristic for small sized materials. For transplantation were cellularized grafts obtained from biological materials of 44,31mm³±2,72mm³, with chondrocytes (n=18) and mesenchymal stem cells (MSC) (n=20). With chondrocytes in a well of 96-well microplates (Mp96) were cellularized 7 grafts with 2.8x10⁶±2.38x10⁵cells/graft and in DFCSSG –11 grafts with 2.87x10⁶±3x10⁵cells/graft (p˃0.5). With MSC in Mp96 were cellularized 8 grafts with 1.29x10⁶±2x10⁵cells/graft and in DFCSSG –12 grafts with 1.41x10⁶±3.29x10⁵cells/graft (p˃0.1). All cellularized grafts were held in incubator at 37°C, 5%CO₂for 70±12 minutes and transplanted. Then, all Eppendorf tubes, DFCSSGs and Mp96 were washed from cells, which were counted with Hemocytometer with Trypan blue exclusion. As a result, utilisation of DFCSSG increased cellularization rate of grafts by 36.39±2.63% (p˂0.001). A difference between cells viability depending on devices for grafts cellularization (Mp96 =90.73%±2.54%, DFCSSG =89.41%±4.40%), is absent (p˃0.5).

This paper is focused on the study of the three-dimensional structures of collagen extracted from the umbilical-placental complex with the aim of use in oral-maxillofacial surgery. Collagen was ex-tracted from the umbilical-placental complex by a modified enzymatic method that involves initial purification with different surfactants to remove blood and cellular components and ensure non-im-munogenicity. The null hypothesis of the concerned works consists in the fact that the surfactants used do not act on the collagen structures. Three-dimensional collagen structures were developed by the lyophilization process and were analyzed by scanning electron microscopy, Young’s modulus (elasticity), thermogravimetry and Fourier transform infrared spectroscopy and microscopy.

Background: The existing surgical techniques used to regenerate articular cartilage fail. Utilisation of hierarchical, biphasic structures obtained from osteochondral tissue, through demineralisation, decellularization, longitudinal perforation and combination with chondroprogenitor cells, presents a high potential in cartilage defects regeneration. Material and methods: The research was performed on 36 rabbits, separated equally in two experimental and one control group. In the experimental groups, the experimental osteochondral defects of 4-4.5 mm in depth, were performed with a 3.7 drill bit at the level of weight bearing surface of the medial femoral condyle. In the 1st group the defects were treated with grafts combined with autologous chondrocytes, and in the 2nd group with grafts combined with autologous mesenchymal stem cells. In the control group, cartilaginous defects were treated by transferring the osteochondral plugs taken from the trochlear groove. The rabbits were removed from the experiment at 6 and 12 weeks. The results were evaluated by Unified Histological Score of Regenerated Cartilage (UHSRC). Results: At 6 weeks, according to UHSRC, the 1st group had 28.33±1.53 points, the 2nd group –27.67±2.08 points and the control group –26.33±1.53 points (p˃0.1; p˃0.2). At 12 weeks the 1st group had 18.68±5 points, the 2nd group –14.89±3.76 points and the control group –17.22 ±4.84 points (p˃0.5; p˃0.2). Conclusions: According to UHSRC, the experimental groups don’t show a significant difference compared to the control group at 6 and 12 weeks, also the quality of regenerated cartilage is poor.