Biological macromolecules in tissue engineering

2022 ◽  
pp. 381-392
Author(s):  
Pandurang Appana Dalavi ◽  
Sesha Subramanian Murugan ◽  
Sukumaran Anil ◽  
Jayachandran Venkatesan
Keyword(s):  
Tissue Engineering ◽  
Biological Macromolecules

scholarly journals Synthesis and Characterization of Poly(lactic-co-glycolic) Acid Nanoparticles-Loaded Chitosan/Bioactive Glass Scaffolds as a Localized Delivery System in the Bone Defects

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
K. Nazemi ◽  
F. Moztarzadeh ◽  
N. Jalali ◽  
S. Asgari ◽  
M. Mozafari
Keyword(s):  
Tissue Engineering ◽  
Bioactive Glass ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Glycolic Acid ◽  
Plga Nanoparticles ◽  
Biological Macromolecules ◽  
High Porosity ◽  
Tissue Engineering Scaffolds ◽  
Localized Delivery

The functionality of tissue engineering scaffolds can be enhanced by localized delivery of appropriate biological macromolecules incorporated within biodegradable nanoparticles. In this research, chitosan/58S-bioactive glass (58S-BG) containing poly(lactic-co-glycolic) acid (PLGA) nanoparticles has been prepared and then characterized. The effects of further addition of 58S-BG on the structure of scaffolds have been investigated to optimize the characteristics of the scaffolds for bone tissue engineering applications. The results showed that the scaffolds had high porosity with open pores. It was also shown that the porosity decreased with increasing 58S-BG content. Furthermore, the PLGA nanoparticles were homogenously distributed within the scaffolds. According to the obtained results, the nanocomposites could be considered as highly bioactive bone tissue engineering scaffolds with the potential of localized delivery of biological macromolecules.

Crosslinked hydrogels based on biological macromolecules with potential use in skin tissue engineering

2016 ◽  
Vol 84 ◽  
pp. 174-181 ◽  
Author(s):  
Raluca Vulpe ◽  
Marcel Popa ◽  
Luc Picton ◽  
Vera Balan ◽  
Virginie Dulong ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Skin Tissue ◽  
Biological Macromolecules ◽  
Skin Tissue Engineering ◽  
Potential Use

Effects of flavonoids incorporated biological macromolecules based scaffolds in bone tissue engineering

2018 ◽  
Vol 110 ◽  
pp. 74-87 ◽  
Author(s):  
S. Preethi Soundarya ◽  
V. Sanjay ◽  
A. Haritha Menon ◽  
S. Dhivya ◽  
N. Selvamurugan
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Biological Macromolecules

Observation of biological macromolecules using various electron microscopic methods

1978 ◽  
Vol 36 (2) ◽  
pp. 170-171
Author(s):  
Mitsuo Ohtsuki ◽  
Michael Sogard
Keyword(s):  
Electron Microscope ◽  
Phase Contrast ◽  
Image Interpretation ◽  
Density Lipoprotein ◽  
Biological Macromolecules ◽  
Contrast Effects ◽  
Biological Structure ◽  
Electron Microscopic ◽  
Structural Investigations ◽  
Staining Techniques

Structural investigations of biological macromolecules commonly employ CTEM with negative staining techniques. Difficulties in valid image interpretation arise, however, due to problems such as variability in thickness and degree of penetration of the staining agent, noise from the supporting film, and artifacts from defocus phase contrast effects. In order to determine the effects of these variables on biological structure, as seen by the electron microscope, negative stained macromolecules of high density lipoprotein-3 (HDL3) from human serum were analyzed with both CTEM and STEM, and results were then compared with CTEM micrographs of freeze-etched HDL3. In addition, we altered the structure of this molecule by digesting away its phospholipid component with phospholipase A2 and look for consistent changes in structure.

Measurement and Reduction of Radiation Damage in Frozen Hydrated Crystalline Specimens

1978 ◽  
Vol 36 (3) ◽  
pp. 70-77 ◽  
Author(s):  
R.M. Glaeser ◽  
S.B. Hayward
Keyword(s):  
Diffraction Pattern ◽  
Structural Information ◽  
Structural Disorder ◽  
Structural Features ◽  
Biological Macromolecules ◽  
Diffraction Intensity ◽  
Object Structure ◽  
Specimen Material ◽  
Unit Cells ◽  
Identical Unit

Highly ordered or crystalline biological macromolecules become severely damaged and structurally disordered after a brief electron exposure. Evidence that damage and structural disorder are occurring is clearly given by the fading and eventual disappearance of the specimen's electron diffraction pattern. The fading and disappearance of sharp diffraction spots implies a corresponding disappearance of periodic structural features in the specimen. By the same token, there is a oneto- one correspondence between the disappearance of the crystalline diffraction pattern and the disappearance of reproducible structural information that can be observed in the images of identical unit cells of the object structure. The electron exposures that result in a significant decrease in the diffraction intensity will depend somewhat upon the resolution (Bragg spacing) involved, and can vary considerably with the chemical makeup and composition of the specimen material.

Concentration determination of chromatin in unstained resin-embedded sections by means of Z-contrast in STEM

1990 ◽  
Vol 48 (2) ◽  
pp. 186-187
Author(s):  
M. Haider ◽  
B. Bohrmann
Keyword(s):  
Energy Loss ◽  
Freeze Substitution ◽  
Biological Macromolecules ◽  
Local Concentration ◽  
E Coli ◽  
Concentration Determination ◽  
Phosphorous Content ◽  
Z Contrast ◽  
Electron Energy Loss

The technique of Z-contrast in STEM offers the possibility to determine the local concentration of macromolecules like lipids, proteins or DNA. Contrast formation depends on the atomic composition of the particular structure. In the case of DNA, its phosphorous content discriminates it from other biological macromolecules. In our studies, sections of E. coli, the dinoflagellate Amphidinium carterae and Euglena spec. cells were used which were obtained by cryofixation followed by freeze-substitution into acetone with 3% glutaraldehyde. The samples were then embedded either in Lowicryl HM20 at low temperature or in Epon at high temperature. Sections were coated on both sides with 30Å carbon.The DF- and the inelastic image have been recorded simultaneously with a Cryo-STEM. This Cryo-STEM is equipped with a highly dispersive Electron Energy Loss Spectrometer. With this instrument pure Z-contrast can be achieved either with a Filtered DF-image divided by the inelastic image or, as is used in this paper, by dividing the conventional DF-image by an inelastic image which has been recorded with an inelastic detector whose response is dependent on the total energy loss of the inelastically scattered electrons.

Resolution assessment from spectral signal-to-noise ratios

1987 ◽  
Vol 45 ◽  
pp. 746-747
Author(s):  
M. Unser ◽  
B.L. Trus ◽  
A.C. Steven
Keyword(s):  
Electron Microscopy ◽  
Limiting Factor ◽  
Biological Macromolecules ◽  
Signal To Noise ◽  
Differential Phase ◽  
Traditional Measure ◽  
Spectral Signal ◽  
Two Measures ◽  
Diffraction Patterns ◽  
Averaging Techniques

Since the resolution-limiting factor in electron microscopy of biological macromolecules is not instrumental, but is rather the preservation of structure, operational definitions of resolution have to be based on the mutual consistency of a set of like images. The traditional measure of resolution for crystalline specimens in terms of the extent of periodic reflections in their diffraction patterns is such a criterion. With the advent of correlation averaging techniques for lattice rectification and the analysis of non-crystalline specimens, a more general - and desirably, closely compatible - resolution criterion is needed. Two measures of resolution for correlation-averaged images have been described, namely the differential phase residual (DPR) and the Fourier ring correlation (FRC). However, the values that they give for resolution often differ substantially. Furthermore, neither method relates in a straightforward way to the long-standing resolution criterion for crystalline specimens.

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