"Applications of Bioactive Glass in Tissue Engineering"

Abstract

Bioactive glasses (BIO) have gained ground in the field of biomedicine science due to their ability to enhance osteogenesis and angiogenesis. Bioactive glasses were first introduced by Hench and his collaborators in the late 1960s. The 45S5 Bioglass (SiO-CaO-Na2O-P2O5) was the first artificial inorganic material that was able to connected to the living bone to create a stable and tight connected interface. By mixing different percentages of these four oxides, several types of bioactive glasses have been developed to improve their intrinsic properties. Other oxides may also be added to provide specific therapeutic actions.

One of the challenges in tissue engineering is growing new ones bioactive materials that present important properties such as biodegradation, osteoconductivity, controlled degradation and so on combine with natural or synthetic polymers which will provide easier handling of the composite material as well as the ability to administer drugs. It is therefore of utmost importance to develop bioactive scaffolds glasses that will be able to degrade in a controlled manner and form a layer of calcium phosphate that will allow adhesion, the cell proliferation and differentiation. These scaffolds should have mechanical properties similar to those of the tissue to be replace and have sufficient porosity for cell migration and angiogenesis. It is unlikely that a single material will solve this challenge engineering.

The purpose of this master's thesis is to analyze the role and impact of bioactive glasses in tissue engineering applications.

TASIOU Kalipso

"Investigation of the pre-analytical treatment of biological fluids for the determination of biomarkers by LC-MS/MS spectrometry"

Abstract

Biomarkers are molecules whose determination in clinical laboratories has great diagnostic and clinical value. The determination of biomarkers can be performed in various biological fluids, with blood and urine being the most widely used. Liquid chromatography coupled to mass spectrometry (LC-MS/MS) is one of the most widely applied analytical techniques in biomarker analysis, due to its advantages over others, such as high specificity and sensitivity, speed, small sample volume, simultaneous determination of multiple analytes, determination of thermally unstable and non-volatile compounds, the avoidance of derivatization of the analytes, etc.

The pre-analytical processing of biological samples is a mandatory step for the determination of various biomarkers by liquid chromatography-mass spectrometry. Its importance is decisive, and ensures reliable results for the correct diagnosis, prediction, monitoring of diseases and determination of drug levels.

The purpose of this work is to review and present selected sample preparation techniques of biological fluids suitable for the analysis of biomarkers, applying the LC-MS/MS methodology.

Protein precipitation, solid phase extraction and liquid-liquid extraction are the mainly used pretreatment techniques. Moreover, new techniques or evolution of classic techniques are used today, allowing the analysis of smaller volumes of biological fluids by using smaller volumes of elution solvents. These include solid phase microextraction, salting-out assisted liquid–liquid extraction, supported liquid extraction, fabric phase sorptive extraction, stir bar sorptive extraction, microextraction by packed sorbent and monolithic spin column extraction. Additional technologies, such as phospholipid removal plates, magnetic beads, turbulent flow extraction, as well as, the use of newer materials, such as carbon nanotubes, restricted access materials, immunosorbents, molecularly imprinted polymers and aptamers, enable greater recovery of analytes and removal of interfering substances, and resulting to more specific and sensitive biomarkers identification and quantification.

In conclusion, the selection of the most suitable sample preparation technique for the determination of specific biomarker, should be based on the evaluation of the following parameters: the chemical properties of the biomarker, the cost and the time required to perform the specific analysis as well as the available laboratory equipment. Furthermore, the performance offered by each technique in terms of sensitivity and specificity is probably the most important factor that will affect the choice of the applied technique for routine laboratory analyses.

PAPACHARISIS Vasilios

"CAR T-cell therapy in liquid and solid tumors"

Abstract

CAR T cell therapy is a type of immunotherapy that utilizes synthetic, chimeric antigen receptors (CARs) to reprogram T cell antigen specificity and function. These genetically modified T cells are expanded in the lab and then infused into the patient, granting them the ability to fight certain types of diseases such as cancer. CAR T cell therapy has changed the way we view personalized cancer treatment especially in hematologic malignancies, altering the landscape of T cell-based immunotherapy. The MHC-independent CAR-mediated T cell recognition of malignant cells has led to a plethora of targets being tested for a wide variety of tumors. The targeting of CD19, a cell surface molecule expressed on normal B cells as well as in a vast majority of B cell malignancies, and BCMA, expressed on differentiated B cells and cancerous plasma cells, showed great results in the treatment of relapsed or refractory leukemia, lymphoma, and multiple myeloma, with significant clinical responses and high rates of complete remission. Despite the durable remissions in hematologic malignancies, CAR T cell therapy is limited by potentially severe toxicities. Cytokine release syndrome and neurological toxicities are still of great concern to the safety issue following CAR T cell infusion. Treatment of solid tumors using CAR T cell therapy is still a major challenge due to the heterogeneity of such tumors, their physical barriers, and the highly immunosuppressive nature of the solid tumor microenvironment. 

TOLIS Rafail