(625f) Bioadhesive Hydrogels with Antimicrobial and Osteoinductive Properties for Periodontal Applications

Bioadhesive Hydrogels with Antimicrobial and Osteoinductive
Properties for Periodontal Applications

Ehsan Shirzaei Sani¹, Aline Yaghsezian², Zheng Cao³, Makiko
Ishii², Nooshin Zandi³,
Giuseppe Intini⁴, Flavia Pirih², Nasim Annabi^1,5

¹Chemical and Biomolecular Engineering Department,
University of California - Los Angeles, Los Angeles, CA, USA

²Division of Constitutive and Regenerative Sciences,
UCLA School of Dentistry, Los Angeles, CA 90095, USA

³Department of Chemical Engineering, Northeastern
University, Boston, MA, USA

⁴Division of Periodontology, Department of Oral
Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston,
MA, USA

⁵Center for Minimally Invasive Therapeutics (C-MIT),
California NanoSystems Institute (CNSI), University
of California - Los Angeles, Los Angeles, CA, USA

Introduction

Dental
implants have become the standard of care for partial or fully edentulous
patients, which has led to an increase in the number of patients affected by peri-implant
diseases (PIDs). These diseases are characterized by the inflammation of the
soft tissue surrounding the implants, infection, and bone loss around the
implants. Since implant placements continue increasing, it is predicted that
PIDs will become one of the most significant dental diseases of the future. In
addition, many patients do not have the adequate bone volume to support the
implant. Therefore, there is an unmet need to develop a multifunctional
adhesive hydrogel with combined osteoinductivity and
antimicrobial properties as a matrix for treatment of PIDs and periodontal bone
defects. In the current study, we aimed to engineer a novel antimicrobial and
osteoinductive hydrogel adhesives for this purpose, which are composed of
gelatin methacryloyl (GelMA), osteoinductive silicate nanoparticles (SN), and
antimicrobial peptide (AMP).

Materials
and Methods

 All
chemicals were purchased at analytical grade and used without further
purification. GelMA was synthesized through the methacrylation
of cold water fish skin gelatin (Sigma) with methacrylic
anhydride (Sigma), according to a procedure described previously [1]. Hydrogels
were photopolymerized using Eosin Y (0.1 mM) as photoinitiator, Triethanolamine (1.5 %(w/v)) as a co-initiator and N-vinylcaprolactam
(1 %(w/v)) as a co-monomer. The hydrogel prepolymer solution containing 15
%(w/v) GelMA, 0.1 %(w/v) antimicrobial peptide (AMP) Tet213 (CPC Scientific,
CA, USA), 200 µg/ml osteoinductive nanoparticles (E.E.S Cosmetic Solutions, USA)
and photoinitiators, were mixed gently and photopolymerized for 60-120 sec
under visible light using a VALO^® LED dental curing light (Ultradent Products Inc., 1000-3200 mW/cm²,
395-480).

Results
and Discussion

The engineered hydrogels could be rapidly crosslinked in situ using the LED dental curing light. Our in
vitro characterization demonstrated that SN-loaded GelMA-AMP hydrogels
exhibited high cytocompatibility and supported the growth of W-20-17 mouse bone
marrow stromal cells encapsulated inside the hydrogel. We also found that the
engineered hydrogels had high antimicrobial activity against both Gram-positive (G+) methicillin resistant Staphylococcus
aureus (MRSA), and Gram-negative (G-) Porphyromonas
gingivalis (a pathogenic bacterium found in PIDs) and E. coli bacteria due to the
presence of AMP. Additionally, the incorporation of SNs into the
engineered hydrogels induced osteogenic differentiation of the cells in
vitro. Furthermore, our in vivo studies showed that the hydrogel precursor
could be readily delivered and photocrosslinked in situ to seal calvarial bone defects in mice for up to 42 days (Figure
1). Similarly, the bioadhesive was applied to large periodontal bone
defects in miniature pigs, showing promising bone regenerative capacity of the
engineered bioadhesive hydrogels.

Conclusion

In this study, we synthesized
photocrosslinkable osteoinductive gelatin-based hydrogels that possessed high antimicrobial
properties and exhibited high cytocompatibility in vitro using W-20-17
cells. In adhesion, the in vivo application of adhesive hydrogels using both
small (mouse calvarial defect model) and large (periodontal bone defects in
minipigs) animals showed high stability and bone regenerative capacity. The
engineered hydrogel adhesives may constitute an effective strategy to prevent
bacterial infection and promote bone regeneration around dental implants.

Acknowledgment

Authors
acknowledge the support from American Heart Association (AHA, 16SDG31280010), National
Institutes of Health (NIH) (R01EB023052; R01HL140618), C-DOCTOR (Center for
Dental, Oral, & Craniofacial Tissue & Organ Regeneration), and
University of California-Los Angeles.

References

[1] A. Assmann, A.Vegh, E. Shirzaei Sani,  G. Cheng, G. U.Ruiz-Esparza,
X. Wang, A. D. Lassaletta, S. Gangadharan,
A. S. Weiss, A. Khademhosseini, Biomaterials,
2017, 140, 115-127.