A review of the biological response to ionic dissolution products from bioactive glasses and glass-ceramics

Review of bioactive glass: from Hench to hybrids.

I. Introduction A FUNCTIONAL relationship between cell growth and the initiation and progression of events associated with differentiation has been a fundamental question challenging developmental biologists for more than a century. In the case of bone, as observed with other cells and tissue, the relationship of growth and differentiation must be maintained and stringently regulated, both during development and throughout the life of the organism, to support tissue remodeling. For many years, bone was defined anatomically and examined largely in a descriptive manner by ultrastructural analysis and by biochemical and histochemical methods. These studies provided the basis for our understanding of bone tissue organization and orchestration of the progressive recruitment, proliferation, and differentiation of the various cellular components of bone tissue. Now, complemented by an increased knowledge of molecular mechanisms that are associated with and regulate expression of genes encoding phenotypic compone...

Molecular mechanism mediating proliferation, defferentiation interralationships during progressie development of the osteoblast phenotype

Traditionally, bioactive glasses have been used to fill and restore bone defects. More recently, this category of biomaterials has become an emerging research field for bone tissue engineering applications. Here, we review and discuss current knowledge on porous bone tissue engineering scaffolds on the basis of melt-derived bioactive silicate glass compositions and relevant composite structures. Starting with an excerpt on the history of bioactive glasses, as well as on fundamental requirements for bone tissue engineering scaffolds, a detailed overview on recent developments of bioactive glass and glass-ceramic scaffolds will be given, including a summary of common fabrication methods and a discussion on the microstructural-mechanical properties of scaffolds in relation to human bone (structure-property and structure-function relationship). In addition, ion release effects of bioactive glasses concerning osteogenic and angiogenic responses are addressed. Finally, areas of future research are highlighted in this review.

https://pure.tue.nl/ws/files/3034662/Metis245608.pdf

Bioactive Glass and Glass-Ceramic Scaffolds for Bone Tissue Engineering

The use of bone grafts is the standard to treat skeletal fractures, or to replace and regenerate lost bone, as demonstrated by the large number of bone graft procedures performed worldwide. The most common of these is the autograft, however, its use can lead to complications such as pain, infection, scarring, blood loss, and donor-site morbidity. The alternative is allografts, but they lack the osteoactive capacity of autografts and carry the risk of carrying infectious agents or immune rejection. Other approaches, such as the bone graft substitutes, have focused on improving the efficacy of bone grafts or other scaffolds by incorporating bone progenitor cells and growth factors to stimulate cells. An ideal bone graft or scaffold should be made of biomaterials that imitate the structure and properties of natural bone ECM, include osteoprogenitor cells and provide all the necessary environmental cues found in natural bone. However, creating living tissue constructs that are structurally, functionally and mechanically comparable to the natural bone has been a challenge so far. This focus of this review is on the evolution of these scaffolds as bone graft substitutes in the process of recreating the bone tissue microenvironment, including biochemical and biophysical cues.

Scaffold Design for Bone Regeneration

Background Cultured meat forms part of the emerging field of cellular agriculture. Still an early stage field it seeks to deliver products traditionally made through livestock rearing in novel forms that require no, or significantly reduced, animal involvement. Key examples include cultured meat, milk, egg white and leather. Here, we focus upon cultured meat and its technical, socio-political and regulatory challenges and opportunities. Scope and approach The paper reports the thinking of an interdisciplinary team, all of whom have been active in the field for a number of years. It draws heavily upon the published literature, as well as our own professional experience. This includes ongoing laboratory work to produce cultured meat and over seventy interviews with experts in the area conducted in the social science work. Key findings and conclusions Cultured meat is a promising, but early stage, technology with key technical challenges including cell source, culture media, mimicking the in-vivo myogenesis environment, animal-derived and synthetic materials, and bioprocessing for commercial-scale production. Analysis of the social context has too readily been reduced to ethics and consumer acceptance, and whilst these are key issues, the importance of the political and institutional forms a cultured meat industry might take must also be recognised, and how ambiguities shape any emergent regulatory system.

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Bringing cultured meat to market: Technical, socio-political, and regulatory challenges in cellular agriculture

The safety of nickel containing dental alloys.

Pre-warming of dental composites

Conventional 3D bioprinting allows fabrication of 3D scaffolds for biomedical applications. In this contribution we present a cryogenic 3D printing method able to produce stable 3D structures by utilising the liquid to solid phase change of a composite hydrogel (CH) ink. This is achieved by rapidly cooling the ink solution below its freezing point using solid carbon dioxide (CO2) in an isopropanol bath. The setup was able to successfully create 3D complex geometrical structures, with an average compressive stiffness of O(1) kPa (0.49 ± 0.04 kPa stress at 30% compressive strain) and therefore mimics the mechanical properties of the softest tissues found in the human body (e.g. brain and lung). The method was further validated by showing that the 3D printed material was well matched to the cast-moulded equivalent in terms of mechanical properties and microstructure. A preliminary biological evaluation on the 3D printed material, coated with collagen type I, poly-L-lysine and gelatine, was performed by seeding human dermal fibroblasts. Cells showed good attachment and viability on the collagen-coated 3D printed CH. This greatly widens the range of applications for the cryogenically 3D printed CH structures, from soft tissue phantoms for surgical training and simulations to mechanobiology and tissue engineering.

/pdf/cryogenic-3d-printing-of-super-soft-hydrogels-3e76hlrdyi.pdf

Cryogenic 3D Printing of Super Soft Hydrogels

One of the major factors in the therapeutic success of bone tissue engineered scaffolds is the ability of the construct to vascularise post implantation. One of the approaches for improving vascularisation within scaffolds has been to co-culture human umbilical vein endothelial cells (HUVECS) with human osteoblasts (HOBS), which may then promote vascularisation and facilitate tissue regeneration. However, in order to mimic a natural physiological niche it is vital that the scaffold is able to support and promote the proliferation of both cell types and thus become a viable tissue engineered construct. In this study we report the development of a porous bioactive glass–ceramic construct and examine the interaction with human umbilical vein endothelial cells (HUVEC’s) and human osteoblast-like cell both in mono and co-culture. The study clearly demonstrated that the scaffolds were able to support both endothelial and human osteoblast cell proliferation both in mono and co-culture. A comparison of the proliferation response of HUVEC and HOB in mono-culture on the test scaffolds and the commercial porous hydroxyapatite was assessed over a 28 day period (4, 7, 14, 21 and 28 days), using alamar BlueTM assay. Proliferation of HOB cells seeded in the scaffolds was consistently shown to be above those observed on commercial HA scaffolds.

Lucy Di Silvio

Papers

Bringing cultured meat to market: Technical, socio-political, and regulatory challenges in cellular agriculture

The safety of nickel containing dental alloys.

Pre-warming of dental composites

Cryogenic 3D Printing of Super Soft Hydrogels

A porous scaffold for bone tissue engineering/45S5 Bioglass® derived porous scaffolds for co-culturing osteoblasts and endothelial cells