Shear-Induced Cycloreversion Leading to Shear-Thinning and Autonomous Self-Healing in an Injectable, Shape-Holding Collagen Hydrogel.

injectable extracellular matrix (ECM) derived hydrogels that are suitable for cell encapsulation have always been the holy grail in tissue engineering. Nevertheless, these hydrogels still fall short today of meeting three crucial criteria: (a) flexibility on the injectability time window, (b) autonomous self-healing of the injected hydrogel, and (c) shape-retention under aqueous conditions. Here we report the development of a collagen-based injectable hydrogel, cross-linked by cycloaddition reaction between furan and maleimide groups, that (a) is injectable up to 48 h after preparation, (b) can undergo complete autonomous self-healing after injection, (c) can retain its shape and size over several years when stored in the buffer, (d) can be degraded within hours when treated with collagenase, (e) is biocompatible as demonstrated by cell-culture, and (f) is completely resorbable when implanted subcutaneously in rats without causing any inflammation.

Potential therapeutic strategies for photoreceptor degeneration: the path to restore vision.

Photoreceptors (PRs), as the most abundant and light-sensing cells of the neuroretina, are responsible for converting light into electrical signals that can be interpreted by the brain. PR degeneration, including morphological and functional impairment of these cells, causes significant diminution of the retina's ability to detect light, with consequent loss of vision. Recent findings in ocular regenerative medicine have opened promising avenues to apply neuroprotective therapy, gene therapy, cell replacement therapy, and visual prostheses to the challenge of restoring vision.

Potential neuroprotective effect of stem cells from apical papilla derived extracellular vesicles enriched by lab-on-chip approach during retinal degeneration.

Retinal degeneration (RD) is recognized as a frequent cause of visual impairments, including inherited (Retinitis pigmentosa) and degenerative (age-related macular) eye diseases. Dental stem cells (DSCs) have recently demonstrated a promising neuroprotection potential for ocular diseases through a paracrine manner carried out by extracellular vesicles (EVs). However, effective isolation of EVs is still challenging, and isolation methods determine the composition of enriched EVs and the subsequent biological and functional effects.

Scaffold free retinal pigment epithelium sheet engineering using modified alginate-RGD hydrogel.

Tissue-specific extracellular matrix (ECM) plays a critical role in cell survival and homeostasis, which are particularly essential for directing differentiation of different complex tissues such as retina. However, ECM maintenance should be considered to design an effective therapeutic strategy for retina regeneration. To achieve this, cell sheet engineering has emerged as a growing approach to closely reconstruct basal membrane of cells through a scaffold-free manner.