Bioactive Nanoengineered Hydrogels for Bone Tissue Engineering: A Growth-Factor-Free Approach

Abstract

Despite bone's impressive ability to heal after traumatic injuries and fractures, a significant need still exists for developing strategies to promote healing of nonunion defects. To address this issue, we developed collagen-based hydrogels containing two-dimensional nanosilicates. Nanosilicates are ultrathin nanomaterials with a high degree of anisotropy and functionality that results in enhanced surface interactions with biological entities compared to their respective three-dimensional counterparts. The addition of nanosilicates resulted in a 4-fold increase in compressive modulus along with an increase in pore size compared to collagen-based hydrogels. In vitro evaluation indicated that the nanocomposite hydrogels are capable of promoting osteogenesis in the absence of any osteoinductive factors. A 3-fold increase in alkaline phosphatase activity and a 4-fold increase in the formation of a mineralized matrix were observed with the addition of the nanosilicates to the collagen-based hydrogels. Overall, these results demonstrate the multiple functions of nanosilicates conducive to the regeneration of bone in nonunion defects, including increased network stiffness and porosity, injectability, and enhanced mineralized matrix formation in a growth-factor-free microenvironment.

Hydroxyapatite nanoparticle injectable hydrogel scaffold to support osteogenic differentiation of human mesenchymal stem cells

“…This is indeed unlike other pNIPAM based hydrogels, and generates a hydrogel with lower viscosity than previously reported systems, which has the potential to fill small cracks, fissures and voids within the bone. In addition, growth factor free approaches to injectable composite hydrogels for use in bone augmentation have been limited; recently, Xavier et al (2015) reported nanocomposite hydrogels capable of promoting osteogenesis in the absence of osteoconductive factors; however, the scaffold fabrication technique involved the use of photo crosslinking which raises safety concerns regarding UV exposure not only to implanted cells but also to surrounding tissues during delivery and precludes the use of minimally invasive techniques for deeper tissues (Xavier et al, 2015).…”

Study of extrudability and standoff distance effect during nanoclay-enabled direct printing

“…To investigate the influence of nanoclay additive during nanoclay-enabled direct extrusion printing, Laponite XLG nanoclay is used as both ink material and internal scaffold material. Both Laponite and its nanocomposites have been utilized in different biomedical applications [12,23,24]. As the internal scaffold material during extrusion, Laponite XLG is added to prepare the NIPAAm-Laponite nanocomposite hydrogel precursor to investigate the improvement of the bioink extrudability.…”

Reducing posttreatment relapse in cleft lip palatal expansion using an injectable estrogen–nanodiamond hydrogel

“…We used methacrylated glycol chitosan G, which enabled local delivery of E2/ND in a minimally invasive manner using blue-light assisted gelification. Such light curing avoids potential adverse effects associated with UV exposure that is required in polymerization of previous hydrogels (68) and it is routinely used in dental practice, adding to the applicability of this system.…”