Alginate in corneal tissue engineering

Abstract

Corneal blindness is the major cause of vision impairment and the fourth-largest leading cause of blindness worldwide. An allograft corneal transplant is the most routine treatment for visual loss. Further complications can occur, such as transplant rejection, astigmatism, glaucoma, uveitis, retinal detachment, corneal ulceration due to reopening of the surgical wounds, and infection. For patients with autoimmune disorders, allografting for chemical burns and infections is contraindicated because of the risk of disease transmission and further complications. Moreover, corrective eye surgery renders the corneas unsuitable for allografting, further increasing the gap between donor tissue demand and supply. Due to these challenges, other therapeutic strategies such as artificial alternatives to donor corneal tissue are being considered. This review focuses on the use of alginate as a building block of therapeutic drugs or cell delivery systems to enhance drug retention and encourage corneal regeneration. The similarity of alginate hydrogel water content to native corneal tissue makes it a promising support structure. Alginates possess desired drug carrier characteristics, such as mucoadhesiveness and penetration enhancing properties. Whilst alginates have been extensively studied for their application in tissue engineering, with many reviews being published, no reviews exist to our knowledge directly looking at alginates for corneal applications. The role of alginate in drug delivery to the surface of the eye and as a support structure (bioinspired tissue scaffold) for corneal tissue engineering is discussed. Biofabrication techniques such as gel casting, electrospinning, and bioprinting to develop tissue precursors and substitutes are compared. Finally, cell and tissue encapsulation in alginate for storage and transport to expand the scope of cell-based therapy for corneal blindness is also discussed in the light of recent applications of alginate in maintaining the function of biofabricated constructs for storage and transport.

Roles of biomaterials in modulating the innate immune response in ocular therapy

“…Another factor that may affect whether the response of the innate immune system is pro-or anti-inflammatory, as previously mentioned, is the intrinsic chemical structure of the nanoparticle. Natural biomaterials such as gelatin (Vandervoort and Ludwig, 2004;Mathurm and Gilhotra, 2011), chitosan (Marõ´a et al, 2003;Enríquez de Salamanca et al, 2006;Tsukamoto et al, 2013;Li et al, 2009;Aşık et al, 2013), collagen (Luis et al, 2016;Simpson et al, 2021;Song et al, 2021), albumin (Zimmer et al, 1994;Tiwari et al, 2021), alginate (Shafie and Fayek, 2013;Kostenko et al, 2022), and HA (de La Fuente et al, 2008;Yenice et al, 2008;Rayahin et al, 2015;Gebe et al, 2017;Guter and Breunig, 2017;Casey-Power et al, 2022) are frequently used as anti-inflammatory agents in eye treatment because they do not cause an inflammatory response…”

The Design and Developments of Protein‐Polysaccharide Biomaterials for Corneal Tissue Engineering

“…Corneal tissue repair and recovery of the native corneal tissue structure Showing less stability and rigidity, muco-adhesiveness is not assisted by great cell adhesiveness. [352,353] Cellulose…”

Alginate-Based Composites for Corneal Regeneration: The Optimization of a Biomaterial to Overcome Its Limits

“…As reported in Section 2 , in corneal TERM, the chosen material must have specific features to fulfill the regeneration purpose. Unmodified alginate alone has some of them, such as biocompatibility, the absence of immunogenic potential, transparency, high swollen state, and bioadherence with host tissue, but, at the same time, it lacks suitable post-swelling mechanical features, opportune cell adhesion properties and a controllable biodegradation rate [ 102 , 139 , 142 , 143 ] For those reasons, the main functionalization and blending techniques, carried out with the aim to fill or improve the characteristics of alginates within the corneal TERM, are summarized in Table 1 and discussed in the subsequent sections. The offered strategies included techniques such as electrospinning [ 55 ] and bioprinting ( Figure 3 ), as they stand for innovative manufacturing methods to create hydrogel-based scaffolds alongside the more conventional injectable or in situ formation methods [ 144 ].…”