Bio‐conjugation of platelet‐rich plasma and alginate through carbodiimide chemistry for injectable hydrogel therapies

Abstract

Alginate is a highly tailorable, biocompatible polymer whose properties can be tuned to mimic the properties of native nucleus pulposus (NP) tissue. Platelet-rich plasma (PRP) is a highly accessible, inexpensive, and readily available mix of pro-regenerative factors. By functionalizing alginate with PRP, a mechanically optimized, bioactive alginate NP analogue may stimulate NP cells to proliferate and accumulate matrix over a longer period of time than if the PRP were solely encapsulated within the hydrogel.In this study, PRP was chemically bound to alginate using carbodiimide chemistry and mechanically, physically, and cytologically compared to plain alginate as well as alginate containing free-floating lyophilized PRP. The alginates were mechanically and physically characterized; PRP-conjugated alginate had similar mechanical properties to controls and had the benefit of retained PRP proteins within the hydrogel. Human nucleus pulposus cells (hNPCs) were seeded within the modified alginates and cultured for 14 days. Quantification data of glycosaminoglycans suggests that PRPincorporated alginate has the potential to increase ECM production within the characterized alginate constructs, and that PRP-functionalized alginate can retain protein within the hydrogel over time. This is the first study to functionalize the milieu of PRP proteins onto alginate and characterize the mechanical and physical properties of the modified alginates. This study also incorporates hNPCs into the characterized PRP-modified alginates to observe phenotypic maintenance when encapsulated within the in situ gelling constructs.

Interpenetrating Hydrogel Networks Enhance Mechanical Stability, Rheological Properties, Release Behavior and Adhesiveness of Platelet-Rich Plasma

“…More recent efforts in the modification of PRP by hydrogels were made by Santana et al, who developed semi-IPNs by mixing autologous Leucocyte derived-PRP and non-crosslinked HA under controlled conditions, obtaining systems with tunable mechanical properties according to HA molecular mass [32]. In a different approach, Sell et al, designed injectable alginate hydrogels, where PRP is chemically bound to the saccharide backbone by carbodiimide chemistry [33]. Physical thermosensitive hydrogels based on PEG-poly(ethylene glycol) polymers were used in vivo in combination with PRP for the treatment of anterior cruciate ligament partial tear.…”

Freeze-Drying of Platelet-Rich Plasma: The Quest for Standardization

“…A promising approach is the combination of PRP with biomaterials such as tissue scaffolds. In this way, alginate was functionalized with FD-PRP by creating amide bonds with PRP peptides through carbodiimide chemistry [53] and compared to PRP encapsulated in alginate. The resulting injectable hydrogels were studied in nucleus pulposus cells and FD-PRP-functionalized alginate showed higher levels of cell survival and increased secretion of glycosaminoglycans (GAGs ) over time, compared to encapsulated PRP.…”

Effect of Fibrin Concentration on the In Vitro Production of Dermo-Epidermal Equivalents

“…By definition, PRP has at least 200-1000 × 103 platelets/µL suspended in plasma, which is attributed to the high content of growth factors in the platelets [26]. PRP has been shown to promote cell growth [27,28] and has been used in various tissue engineering applications in bone [29], [30], cartilage [31,32], skin [33,34], and in vivo applications [35]. These approaches exploit the release of chemo-attractive, angiogenic, proliferative, and putatively pro-regenerative growth factors from PRP, making it suitable as a cell delivery vehicle [36].…”