Bone reservoir: Injectable hyaluronic acid hydrogel for minimal invasive bone augmentation

Evaluation of Alginate and Hyaluronic Acid for Their Use in Bone Tissue Engineering

“…In agreement with these results, cells encapsulated into alginate microcapsules enhanced mRNA expression levels of osteocalcin when compared to monolayer cultures over the course of 21 days [38], while a decrease in OC secretion with HA has been reported in osteoarthritic osteoblast cells [44]. However, in vitro [8] and in vivo [5] studies using modified HA hydrogels with BMP-2 have reported high OC expression, thus, reinforcing the importance of the specific HA used.…”

“…Its high, tissue-like water content and porous structure allows the influx of low molecular weight solutes and nutrients crucial to cellular viability, as well as the transport of cellular waste out of the hydrogel [3]. As biomaterials, the use of injectable hydrogels also allows the administration of the material through minimally invasive techniques, to fill any area with a good physical integration into the defect, to incorporate cells or various therapeutic agents (e.g., growth factors) with a facile and homogenous distribution within any defect [4][5][6][7]. Therefore, hydrogels have been identified to be suitable as bone and cartilage repair materials because they can be carriers for growth and morphogenetic factors to exert host cell chemotaxis, proliferation, differentiation and new tissue formation at the site of injury or defect [8].…”

“…HA is one of the main components of the extracellular matrix present in all connective tissues [20] and involved in a variety of biological functions [5,21], including direct receptor-mediated effects on cell adhesion, growth and migration [22], as well as acting as a signaling molecule in cell mortality [23], inflammation [24] or wound healing [25]. HA hydrogels have been used as vehicle for delivery of BMP-2 in vitro [5,8] and in vivo [21], as well for the delivery of biphosphonates [21]. In vitro studies using derivatized hyaluronic acid (Hyffa-11) have shown to support cell attachment and growth, and to induce ALP activity and osteocalcin expression in a murine fibroblast cell line when containing rhBMP-2 [8].…”

Hyaluronic Acid Bioconjugates for the Delivery of Bioactive Molecules

“…Figure 11. Schematic representation of different HA activation methods and the following conjugation to proteins: (A) random conjugation of amino groups of proteins to carboxylic groups of HA [24]; (B) Slight HA oxidation in the presence of periodate and conjugation of HA-ALD with N-terminal primary amine group of proteins [78,79]; (C) Modification of HA with an acetal spacer for selective conjugation to the N-terminal amino groups after hydrolysis to the active aldehyde of the polymer [65]; and (D) Coupling of amino glycerol to HA carboxylic groups and partial oxidation for selective N-terminal conjugation to proteins [82]. Yang and co-workers applied this chemistry for the site-specific modification of human growth hormone (hGH) and interferon-α (IFNα) [78,79].…”

“…Varghese et al proposed a simple and versatile synthetic strategy to graft aldehyde moieties on HA without compromising the structural integrity of the polymer [81]. Amino glycerol was coupled to some HA carboxylic groups by exploiting the carbodiimide chemistry with hydroxybenzotriazole [82] ( Figure 11, Panel D). The authors reported that the flexible vicinal diols of glycerol have a faster reaction kinetics of oxidation with respect the C2-C3 vicinal diols in trans geometry in the HA backbone.…”