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Tissue Engineering

Tissue Engineering - Poster Session E

Poster BB7 - Fabricating and Testing Gold Nanoparticle (AuNP) Tissue Grafts

Saturday, October 26, 2024
10:00 AM - 11:00 AM EST
Location: Exhibit Hall E, F & G

Introduction:  Anterior cruciate ligament (ACL) injuries are among the most common sporting injuries in the world, and the most common treatment for ACL tears is surgical reconstruction. Typically, the patient’s torn ACL is replaced by a tendon autograft (patient’s tissue) or an allograft (cadaver tissue). This study's primary objective concerns ACL reconstruction, which is the failure of ACL grafts to remodel into a functional ligament. This failure can compromise overall structural integrity leading to instability, reinjury, and/or Osteoarthritis. An ideal ACL reconstruction would involve “ligamentization,” where the ACL graft remodels into a structure similar to the mature native ligament. Ligamentization involves revascularization, fibroblastic invasion, biomechanical stimulation, and collagen synthesis. To enhance this critical step in the healing process, we have been investigating the conjugation of 20 nm gold nanoparticles (AuNPs) to biological graft materials. It is hypothesized that utilizing AuNPs will enhance cellular migration and population while mitigating the inflammatory response.

Materials and

Methods:  The test specimens consisted of two groups. In one group, the grafts were exposed to AuNPs for 5 minutes to allow conjugation. The second group exposed the grafts for 10 minutes to allow conjugation. Dehydrated human cadaver tissue (posterior tibialis tendon) was obtained from MTF and rehydrated in a sterile PBS solution. The grafts were cut into approximate 2.5 cm strips and placed in a 50 ml tube with sterile PBS. The conjugation solution consisted of a 3 mM concentration of sterile genipin. The genipin solutions were placed in the 50 ml tubes and the grafts were then added. To prepare the functionalized AuNPs, cysteine (0.1mM) was mixed with the AuNPs and then added to the genipin-crosslinked grafts. The grafts were exposed to the AuNP conjugation solution for 5 minutes and a second set of grafts were exposed for 10 minutes. After conjugation, the grafts were rinsed in sterile PBS and analyzed.

Results, Conclusions, and Discussions: Neutron Activation Analysis (NAA) was performed to verify the amount of AuNP attached to the grafts. The data indicated that the longer time (10 min) had higher attachment but the data was not significant.
UV/VIS was performed to determine if any AuNPs were detaching from the grafts after conjugation. The grafts were soaked in sterile PBS up to 24 hours and the PBS was scanned in the UV/VIS. The results demonstrated that the AuNPs were not detaching from the grafts.
Scanning Electron Microscopy was performed to qualify the AuNP attachment. The SEM micrographs displayed AuNP attachment on the tissue grafts but one could not distinguish between the 5-minute incubation and 10-minute incubation time.
PicoGreen Cell Culture Assay was performed using fibroblast cells. The results demonstrated that the AuNP-tissue grafts were biocompatible and had enhanced cellularity as compared to the controlled grafts without any AuNPs.
It was concluded that 5-minute and 10-minute conjugation times were sufficient to attach the AuNPs to the tissue grafts and there were no significant differences between the incubation times. The AuNP grafts displayed improved cellularity over the controlled grafts; AuNPs may be improving cellularity due to the high surface energy of the AuNPs attracting the cells. Future studies are needed to determine how attaching AuNPs to tissue grafts may improve ligamentization and remodeling.

Acknowledgements (Optional):  Material Science and Engineering NSF REU Program