Gentamicin Eluting 3D-Printed Implants for Preventing Post-Surgical Infections in Bone Fractures

Abstract

A surgically implantable device is an inevitable treatment option for millions of people worldwide suffering from diseases arising from orthopedic injuries. A global paradigm shift is currently underway to tailor and personalize replacement or reconstructive joints. Additive manufacturing (AM) has provided dynamic outflow to the customized fabrication of orthopedic implants by enabling need-based design and surface modification possibilities. Surgical grade 316L Stainless Steel (316L SS) is promising with its cost, strength, composition, and corrosion resistance to fabricate 3D implants. This work investigates the possibilities of application of the laser powder bed fusion (L-PBF) technique to fabricate 3D-printed (3DP) implants, which are functionalized with a multilayered antimicrobial coating to treat potential complications arising due to postsurgical infections (PSIs). Postsurgical implant-associated infection is a primary reason for implantation failure and is complicated mainly by bacterial colonization and biofilm formation at the installation site. PLGA (poly-D,L-lactide-co-glycolide), a biodegradable polymer, was utilized to impart multiple layers of coating using the airbrush spray technique on 3DP implant surfaces loaded with gentamicin (GEN). Various PLGA-based polymers were tested to optimize the ideal lactic acid: glycolic acid ratio and molecular weight suited for our investigation. 3D-Printed PLGA-GEN substrates sustained the release of gentamicin from the surface for approximately 6 weeks. The 3DP surface modification with PLGA-GEN facilitated cell adhesion and proliferation compared to control surfaces. The cell viability studies showed that the implants were safe for application. The 3DP PLGA-GEN substrates showed good concentration-dependent antibacterial efficacy against the common PSI pathogen Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis). The GEN-loaded substrates demonstrated antimicrobial longevity and showed significant biofilm growth inhibition compared to control. The substrates offered great versatility regarding the in vitro release rates, antimicrobial properties, and biocompatibility studies. These results radiate great potential in future human and veterinary clinical applications pertinent to complications arising from PSIs, focusing on personalized sustained antibiotic delivery.

Reverse Engineering and 3D Printing of Medical Devices for Drug Delivery and Drug-Embedded Anatomic Implants

“…Wu et al [55] used inkjet technology for 3DP multidrug implants for treating tuberculosis extending into bone. Furthermore, Poudel et al [56] explored the use of laser powder bed fusion to create 3D-printed orthopedic implants from surgical grade 316L stainless steel. The implants are coated with PLGA and loaded with gentamicin to provide sustained antibiotic release, combating post-surgical infections and enhancing cell adhesion, with proven efficacy against common pathogens such as S. aureus and S. epidermidis.…”

Recent Advances in Antibacterial Coatings to Combat Orthopedic Implant-Associated Infections

“…The interest in designing such personalized implants relies on the need to produce safe systems, offering high antibacterial efficacy, improving patient convenience, and providing flexibility according to the patient’s needs. The latter can be achieved by adjusting the implant’s structural and morphological features, mechanical properties, and improving the loading efficacy of antibacterial agents [ 92 , 150 , 151 ].…”

“…The interest in designing such personalized implants relies on the need to produce safe systems, offering high antibacterial efficacy, improving patient convenience, and providing flexibility according to the patient s needs. The latter can be achieved by adjusting the implant s structural and morphological features, mechanical properties, and improving the loading efficacy of antibacterial agents [92,150,151]. In addition to the recent progress in the development of antibacterial coatings, it is worth highlighting recent advances in the surface design of modified orthopedic implants with antibacterial properties.…”