Abstract:Hyaluronic acid (HA) is a glycosaminoglycan with diverse biomedical applications including viscosupplementation of synovial fluid for the treatment osteoarthritis. Current HA viscosupplements such as Synvisc, Orthovisc, and Hyalgan have shown positive effects of reducing pain and improving joint function. The therapeutic efficacy, however, is highly transient, and these viscous fluids suffer from poor injectability. HA nanoparticles were found to modify the rheological properties of a model of the HA viscosupp… Show more
“…The combination of MeHA mixed with HAnp resulted in a hydrogel that exhibited ‘paste-like’ rheological behavior in its precursor solution. Although the underlying mechanism for the resulting paste-like behavior associated with the inclusion of HAnp is currently unknown, it has been hypothesized to be a result of dangling HA chains on the surface of the HAnp 8 . These dangling chains are hypothesized to cause physical entanglements between individual HAnp and entanglements between HAnp and MeHA.…”
Hydrogels are a promising class of materials for tissue regeneration, but they lack the ability to be molded into a defect site by a surgeon because hydrogel precursors are liquid solutions that are prone to leaking during placement. Therefore, although the main focus of hydrogel technology and developments are on hydrogels in their crosslinked form, our primary focus is on improving the fluid behavior of hydrogel precursor solutions. In this work, we introduce a method to achieve paste-like hydrogel precursor solutions by combining hyaluronic acid nanoparticles with traditional crosslinked hyaluronic acid hydrogels. Prior to crosslinking, the samples underwent rheological testing to assess yield stress and recovery using linear hyaluronic acid as a control. The experimental groups containing nanoparticles were the only solutions that exhibited a yield stress, demonstrating that the nanoparticulate rather than the linear form of hyaluronic acid was necessary to achieve paste-like behavior. The gels were also photocrosslinked and further characterized as solids, where it was demonstrated that the inclusion of nanoparticles did not adversely affect the compressive modulus and that encapsulated bone marrow-derived mesenchymal stem cells remained viable. Overall, this nanoparticle-based approach provides a platform hydrogel system that exhibits a yield stress prior to crosslinking, and can then be crosslinked into a hydrogel that is capable of encapsulating cells that remain viable. This behavior may hold significant impact for hydrogel applications where a paste-like behavior is desired in the hydrogel precursor solution.
“…The combination of MeHA mixed with HAnp resulted in a hydrogel that exhibited ‘paste-like’ rheological behavior in its precursor solution. Although the underlying mechanism for the resulting paste-like behavior associated with the inclusion of HAnp is currently unknown, it has been hypothesized to be a result of dangling HA chains on the surface of the HAnp 8 . These dangling chains are hypothesized to cause physical entanglements between individual HAnp and entanglements between HAnp and MeHA.…”
Hydrogels are a promising class of materials for tissue regeneration, but they lack the ability to be molded into a defect site by a surgeon because hydrogel precursors are liquid solutions that are prone to leaking during placement. Therefore, although the main focus of hydrogel technology and developments are on hydrogels in their crosslinked form, our primary focus is on improving the fluid behavior of hydrogel precursor solutions. In this work, we introduce a method to achieve paste-like hydrogel precursor solutions by combining hyaluronic acid nanoparticles with traditional crosslinked hyaluronic acid hydrogels. Prior to crosslinking, the samples underwent rheological testing to assess yield stress and recovery using linear hyaluronic acid as a control. The experimental groups containing nanoparticles were the only solutions that exhibited a yield stress, demonstrating that the nanoparticulate rather than the linear form of hyaluronic acid was necessary to achieve paste-like behavior. The gels were also photocrosslinked and further characterized as solids, where it was demonstrated that the inclusion of nanoparticles did not adversely affect the compressive modulus and that encapsulated bone marrow-derived mesenchymal stem cells remained viable. Overall, this nanoparticle-based approach provides a platform hydrogel system that exhibits a yield stress prior to crosslinking, and can then be crosslinked into a hydrogel that is capable of encapsulating cells that remain viable. This behavior may hold significant impact for hydrogel applications where a paste-like behavior is desired in the hydrogel precursor solution.
“…The MW of HA used for MS fabrication influenced the size of the MS. The MSs made from 697 kDa HA were larger than the MSs prepared from 1058 kDa probably due to the intramolecular crosslinking rather than the intermolecular crosslinking caused by the short length of 697 kDa HA [9]. …”
Section: Resultsmentioning
confidence: 99%
“…2). The MSs were a 3-dimensional porous network structure channeled with 2 ~ 4 ± 0.5 μm pores, which represented higher particle compressibility [9]. Fig.…”
Section: Resultsmentioning
confidence: 99%
“…However, the swelling ratio of CHMs decreases with increasing MW probably due to an increased number of coiled HA chain interactions [12–17]. Because of short length of 697 kDa HA, the chances of intramolecular crosslinking occurring during the fabrication of MSs was expected to be higher than those of intermolecular crosslinking [9]. …”
Section: Resultsmentioning
confidence: 99%
“…The nanoparticle size decreases from 140 nm to 95 nm with increasing the HA molecular weight (MW) from 697 kDa to 1368 kDa [12]. The decrease in nanoparticle size with increasing the MW may be due to intramolecular crosslinking rather than intermolecular crosslinking [9]. However, the flowability of nanoparticles rises dramatically due to the loss of viscous modulus, which is detrimental to dermal fillers.…”
BackgroundHyaluronic acid (HA) dermal biphasic fillers are synthesized for their efficacy in correcting aesthetic defects such as wrinkles, scars and facial contouring defects. The fillers consist of crosslinked HA microspheres suspended in a noncrosslinked HA. To extend the duration of HAs within the dermis and obtain the particle texturing feel, HAs are crosslinked to obtain the suitable mechanical properties.ResultsHyaluronic acid (HA) dermal biphasic fillers are prepared by mixing the crosslinked HA microspheres and the noncrosslinked HAs. The elastic modulus of the fillers increased with raising the volume fraction of the microspheres. The mechanical properties and the particle texturing feel of the fillers made from crosslinked HA (1058 kDa) microspheres suspended in noncrosslinked HA (1368 kDa) are successfully achieved, which are adequate for the fillers.ConclusionsDermal biphasic HA fillers made from 1058 kDa exhibit suitable elastic moduli (211 to 420 Pa) and particle texturing feel (scale 7 ~ 9).
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