Bioengineered Hybrid Collagen Scaffold Tethered with Silver‐Catechin Nanocomposite Modulates Angiogenesis and TGF‐ β Toward Scarless Healing in Chronic Deep Second Degree Infected Burns

2020 ◽  
Vol 9 (12) ◽  
pp. 2000247 ◽  
Author(s):  
Cheirmadurai Kalirajan ◽  
Thanikaivelan Palanisamy
2018 ◽  
Vol 55 (4) ◽  
pp. 691-695
Author(s):  
Tudor Sorin Pop ◽  
Anca Maria Pop ◽  
Alina Dia Trambitas Miron ◽  
Klara Brinzaniuc ◽  
Simona Gurzu ◽  
...  

The use of collagen scaffolds and stem cells for obtaining a tissue-engineering complex has been an important concept in promoting repair and regeneration of the bone tissue. Such units represent important steps in the development of an ideal scaffold-cell complex that would sustain new bone apposition. The aim of our study was to perform a histologic evaluation of the healing of critical-sized bone defects, using a biologic collagen scaffold with adipose-derived mesenchymal stem cells, in comparison to negative controls created in the adjacent bone. We used 16 Wistar rats and according to the study design 2 calvarial bone defects were created in each animal, one was filled with collagen seeded with adipose-derived stem cells and the other one was considered negative control. During the following month, at weekly intervals, the animals were euthanized and the specimens from bone defects were histologically evaluated. The results showed that these scaffolds were highly biocompatible as only moderate inflammation no rejection reactions were observed. Furthermore, the first signs of osseous healing appeared after two weeks accompanied by angiogenesis. Collagen scaffolds seeded with adipose-derived mesenchymal stem cells can be considered a promising treatment option in bone regeneration of large defects.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 832
Author(s):  
Mohammad Mirazul Islam ◽  
Dina B. AbuSamra ◽  
Alexandru Chivu ◽  
Pablo Argüeso ◽  
Claes H. Dohlman ◽  
...  

Collagen scaffolds, one of the most used biomaterials in corneal tissue engineering, are frequently crosslinked to improve mechanical properties, enzyme tolerance, and thermal stability. Crosslinkers such as 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) are compatible with tissues but provide low crosslinking density and reduced mechanical properties. Conversely, crosslinkers such as glutaraldehyde (GTA) can generate mechanically more robust scaffolds; however, they can also induce greater toxicity. Herein, we evaluated the effectivity of double-crosslinking with both EDC and GTA together with the capability of sodium metabisulfite (SM) and sodium borohydride (SB) to neutralize the toxicity and restore biocompatibility after crosslinking. The EDC-crosslinked collagen scaffolds were treated with different concentrations of GTA. To neutralize the free unreacted aldehyde groups, scaffolds were treated with SM or SB. The chemistry involved in these reactions together with the mechanical and functional properties of the collagen scaffolds was evaluated. The viability of the cells grown on the scaffolds was studied using different corneal cell types. The effect of each type of scaffold treatment on human monocyte differentiation was evaluated. One-way ANOVA was used for statistical analysis. The addition of GTA as a double-crosslinking agent significantly improved the mechanical properties and enzymatic stability of the EDC crosslinked collagen scaffold. GTA decreased cell biocompatibility but this effect was reversed by treatment with SB or SM. These agents did not affect the mechanical properties, enzymatic stability, or transparency of the double-crosslinked scaffold. Contact of monocytes with the different scaffolds did not trigger their differentiation into activated macrophages. Our results demonstrate that GTA improves the mechanical properties of EDC crosslinked scaffolds in a dose-dependent manner, and that subsequent treatment with SB or SM partially restores biocompatibility. This novel manufacturing approach would facilitate the translation of collagen-based artificial corneas to the clinical setting.


Burns ◽  
2020 ◽  
Author(s):  
Saeed Naseri ◽  
Mojtaba Golpich ◽  
Tohid Roshancheshm ◽  
Mohammad Ghadimi Joobeni ◽  
Moein Khodayari ◽  
...  
Keyword(s):  

Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 310 ◽  
Author(s):  
Pedro Ortiz ◽  
Juan Carlos Trillo

This paper is devoted to introducing a nonlinear reconstruction operator, the piecewise polynomial harmonic (PPH), on nonuniform grids. We define this operator and we study its main properties, such as its reproduction of second-degree polynomials, approximation order, and conditions for convexity preservation. In particular, for σ quasi-uniform grids with σ≤4, we get a quasi C3 reconstruction that maintains the convexity properties of the initial data. We give some numerical experiments regarding the approximation order and the convexity preservation.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1269
Author(s):  
Gareth Sheppard ◽  
Karl Tassenberg ◽  
Bogdan Nenchev ◽  
Joel Strickland ◽  
Ramy Mesalam ◽  
...  

In tissue engineering, scaffolds are a key component that possess a highly elaborate pore structure. Careful characterisation of such porous structures enables the prediction of a variety of large-scale biological responses. In this work, a rapid, efficient, and accurate methodology for 2D bulk porous structure analysis is proposed. The algorithm, “GAKTpore”, creates a morphology map allowing quantification and visualisation of spatial feature variation. The software achieves 99.6% and 99.1% mean accuracy for pore diameter and shape factor identification, respectively. There are two main algorithm novelties within this work: (1) feature-dependant homogeneity map; (2) a new waviness function providing insights into the convexity/concavity of pores, important for understanding the influence on cell adhesion and proliferation. The algorithm is applied to foam structures, providing a full characterisation of a 10 mm diameter SEM micrograph (14,784 × 14,915 px) with 190,249 pores in ~9 min and has elucidated new insights into collagen scaffold formation by relating microstructural formation to the bulk formation environment. This novel porosity characterisation algorithm demonstrates its versatility, where accuracy, repeatability, and time are paramount. Thus, GAKTpore offers enormous potential to optimise and enhance scaffolds within tissue engineering.


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