Rubidium-Containing Calcium Alginate Hydrogel for Antibacterial and Diabetic Skin Wound Healing Applications.

Rubidium (Rb) is an important microelement for the human body, which can kill and inhibit bacteria. Rubidium-containing polyhydrated ionogens have been applied to treat refractory wounds. In this work, for the first time, Rb was added into calcium alginate hydrogel (Rb-CA gel) and then made into a dressing by freeze-drying.

The Application of Biomaterials to Tissue Engineering Neural Retina and Retinal Pigment Epithelium.

The prevalence of degenerative retinal disease is ever increasing as life expectancy rises globally. The human retina fails to regenerate and the use of human embryonic stem cells (hESCs) and human-induced pluripotent stem cells (hiPSCs) to engineer retinal tissue is of particular interest due to the limited availability of suitable allogeneic or autologous tissue. Retinal tissue and its development are well characterized, which have resulted in robust assays to assess the development of tissue-engineered retina.

Extracellular matrix component expression in human pluripotent stem cell-derived retinal organoids recapitulates retinogenesis in vivo and reveals an important role for IMPG1 and CD44 in the development of photoreceptors and interphotoreceptor matrix.

Unlabelled: The extracellular matrix (ECM) plays an important role in numerous processes including cellular proliferation, differentiation, migration, maturation, adhesion guidance and axonal growth. To date, there has been no detailed analysis of the ECM distribution during retinal ontogenesis in humans and the functional importance of many ECM components is poorly understood. In this study, the expression of key ECM components in adult mouse and monkey retina, developing and adult human retina and retinal organoids derived from human pluripotent stem cells was studied.

3D culture of human pluripotent stem cells in RGD-alginate hydrogel improves retinal tissue development.

Unlabelled: No treatments exist to effectively treat many retinal diseases. Retinal pigmented epithelium (RPE) and neural retina can be generated from human embryonic stem cells/induced pluripotent stem cells (hESCs/hiPSCs). The efficacy of current protocols is, however, limited.

Lack of evidence to support present medial release methods in total knee arthroplasty.

Purpose: The aim of this review was to identify a reliable sequential medial release protocol for restoration of soft tissue balance in total knee arthroplasty of the varus osteoarthritic knee and to allow for improved intraoperative decision-making.

Method: Current medial release sequences and applicability based upon pre-operative deformity have been reviewed. Furthermore, risks associated with over release, and the necessity of medial release, are discussed.

How does laxity after single radius total knee arthroplasty compare with the native knee?

Patients with total knee arthroplasties (TKAs) continue to report dissatisfaction in functional outcome. Stability is a major factor contributing to functionality of TKAs. Implants with single-radius (SR) femoral components are proposed to increase stability throughout the arc of flexion.

Clinical biomechanics of instability related to total knee arthroplasty.

Background: Tibiofemoral instability is a common reason for total knee arthroplasty failure, and may be attributed to soft tissue deficiency and incorrect ligament balancing. There are many different designs of implant with varying levels of constraint to overcome this instability; however there is little advice for surgeons to assess which is suitable for a specific patient, and soft tissue balance testing during arthroplasty is very subjective.

Method: The current theories on primary and secondary soft tissue restraints to anterior/posterior, varus/valgus, and internal/external rotational motion of the knee are discussed.

Encapsulation and culture of mammalian cells including corneal cells in alginate hydrogels.

The potential of cell therapy for the regeneration of diseased and damaged tissues is now widely -recognized. As a consequence there is a demand for the development of novel systems that can deliver cells to a particular location, maintaining viability, and then degrade at a predictable rate to release the cells into the surrounding tissues. Hydrogels have attracted much attention in this area, as the hydrogel structure provides an environment that is akin to that of the extracellular matrix.

Alginate hydrogel has a negative impact on in vitro collagen 1 deposition by fibroblasts.

Hydrogels have been widely investigated as 3D culture substrates because of their reported structural similarity to the extracellular matrix (ECM). Limited ECM deposition, however, occurs within these materials, so the resulting "tissues" bear little resemblance to those found in the body. Here matrix deposition by fibroblasts encapsulated within a calcium alginate (Ca-alg) hydrogel was investigated.

Calcium-alginate hydrogel-encapsulated fibroblasts provide sustained release of vascular endothelial growth factor.

Vascularization of engineered or damaged tissues is essential to maintain cell viability and proper tissue function. Revascularization of the left ventricle (LV) of the heart after myocardial infarction is particularly important, since hypoxia can give rise to chronic heart failure due to inappropriate remodeling of the LV after death of cardiomyocytes (CMs). Fibroblasts can express vascular endothelial growth factor (VEGF), which plays a major role in angiogenesis and also acts as a chemoattractant and survival factor for CMs and cardiac progenitors.

Cell encapsulation using biopolymer gels for regenerative medicine.

There has been a consistent increase in the mean life expectancy of the population of the developed world over the past century. Healthy life expectancy, however, has not increased concurrently. As a result we are living a larger proportion of our lives in poor health and there is a growing demand for the replacement of diseased and damaged tissues.

Reversible mitotic and metabolic inhibition following the encapsulation of fibroblasts in alginate hydrogels.

Limiting cell proliferation without reducing cell viability for in vivo tissue engineering applications is important in co-culture applications where the growth of one cell type must be inhibited to prevent overgrowth of the scaffold at the expense of another cell type. Also, it is vital for maintaining viability of cells in large constructs before vascularisation occurs. In this study we have shown by means of the Thiazolyl blue (MTT) assay and immuno-staining for proliferating cell nuclear antigen (PCNA) that encapsulating fibroblasts in 2% and 5%w/v calcium-alginate at a density of 7.

An alginate hydrogel matrix for the localised delivery of a fibroblast/keratinocyte co-culture.

There is significant interest in the development of tissue-engineered skin analogues, which replace both the dermal and the epidermal layer, without the use of animal or human derived products such as collagen or de-epidermalised dermis. In this study, we proposed that alginate hydrogel could be used to encapsulate fibroblasts and that keratinocytes could be cultured on the surface to form a bilayered structure, which could be used to deliver the co-culture to a wound bed, initially providing wound closure and eventually expediting the healing process. Encapsulation of fibroblasts in 2 and 5% w/v alginate hydrogel effectively inhibited their proliferation, whilst maintaining cell viability allowing keratinocytes to grow uninhibited by fibroblast overgrowth to produce a stratified epidermal layer.