Effects of Propolis Impregnation on Polylactic Acid (PLA) Scaffolds Loaded with Wollastonite Particles against Staphylococcus aureus, Staphylococcus epidermidis, and Their Coculture for Potential Medical Devices

Abstract

Several diseases and injuries cause irreversible damage to bone tissues, which may require partial or total regeneration or replacement. Tissue engineering suggests developing substitutes that may contribute to the repair or regeneration process by using three-dimensional lattices (scaffolds) to create functional bone tissues. Herein, scaffolds comprising polylactic acid and wollastonite particles enriched with propolis extracts from the Arauca region of Colombia were developed as gyroid triply periodic minimal surfaces using fused deposition modeling. The propolis extracts exhibited antibacterial activity against Staphylococcus aureus (ATCC 25175) and Staphylococcus epidermidis (ATCC 12228), which cause osteomyelitis. The scaffolds were characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry, contact angle, swelling, and degradation. Their mechanical properties were assessed using static and dynamic tests. Cell viability/proliferation assay was conducted using hDP-MSC cultures, while their bactericidal properties against monospecies cultures (S. aureus and S. epidermidis) and cocultures were evaluated. The wollastonite particles did not affect the physical, mechanical, or thermal properties of the scaffolds. The contact angle results showed that there were no substantial differences in the hydrophobicity between scaffolds with and without particles. Scaffolds containing wollastonite particles suffered less degradation than those produced using PLA alone. A representative result of the cyclic tests at Fmax = 450 N showed that the maximum strain reached after 8000 cycles is well below the yield strain (i.e., <7.5%), thereby indicating that even under these stringent conditions, these scaffolds will be able to work properly. The scaffolds impregnated with propolis showed a lower % of cell viability using hDP-MSCs on the 3rd day, but these values increased on the 7th day. These scaffolds exhibited antibacterial activity against the monospecies cultures of S. aureus and S. epidermidis and their cocultures. The samples without propolis loads did not show inhibition halos, whereas those loaded with EEP exhibited halos of 17.42 ± 0.2 mm against S. aureus and 12.9 ± 0.5 mm against S. epidermidis. These results made the scaffolds possible bone substitutes that exert control over species with a proliferative capacity for the biofilm-formation processes required for typical severe infectious processes.

Antibacterial and osteoinductive properties of wollastonite scaffolds impregnated with propolis produced by additive manufacturing

“…The antimicrobial activity of propolis has been largely attributed to the presence of organic compounds such as phenols, flavonoids, flavanones, and terpenes, among others [ 63 , 64 ]. The propolis used in this study showed the presence of phenolic compounds and flavonoids, indicating that these may influence the antimicrobial activity found against the evaluated species [ 65 ]. Propolis is characterized by its varied and complex composition, which allows it to affect bacterial species through mechanisms that include damage to the bacterial cell membrane [ 66 ], inhibition of bacterial enzymatic activity [ 67 ], induction of oxidative stress [ 68 ], and modulation of virulence factors [ 69 ].…”

In vitro evaluation of the osteogenic and antimicrobial potential of porous wollastonite scaffolds impregnated with ethanolic extracts of propolis

“…Our activity values align with other studies, which have reported antioxidant activity against the DPPH free radical ranging from 17% to 70% and against the ABTS free radical ranging from 5% to 28% ( Ahn et al, 2007 ). This antioxidant activity can be attributed to the presence of specific components such as phenols and flavonoids found in propolis from this region ( Moreno et al, 2023 ). Furthermore, the antioxidant activity, along with the presence of phenolic compounds and flavonoids, may be associated with antimicrobial activity.…”

“…There is also an increasing focus on human dental MSCs, classified based on their niche within the dental environment ( Machado et al, 2012 ). In the context of regenerative dentistry, scaffolds have been extensively studied in vitro and in vivo , with an emphasis on factors such as scale (micro, nanometric, or hyper-hierarchical), origin (natural or synthetic), product type (massive or customized), manufacturing techniques (including 3D printing and bioprinting) ( Nikolova and Chavali, 2019 ), functionality (3D, 3D functionalized, and 4D) ( Soleymani and Naghib, 2023 ; Wan et al, 2023 ), geometries (periodic or non-periodic) and composition (polymer, metallic, or ceramic) ( Teixeira et al, 2009 ; Higuita-Castro et al, 2012 ; Martin et al, 2019 ; Moreno et al, 2023 ). However, ceramic-based 3D scaffolds have received relatively less attention.…”

“…A variety of studies have explored the potential of wollastonite-based scaffolds in bone tissue engineering. Wollastonite, a calcium silicate, possesses properties such as bioactivity, biocompatibility, and antibacterial effects ( Shao et al, 2017 ; Gao et al, 2023 ; Moreno et al, 2023 ; Yue et al, 2023 ). A combination of compositions and complex geometries (TPMS—triply periodic minimal surfaces) might be favorable for cell behavior ( Ramírez et al, 2019 ) as they can closely mimic natural cortical bone tissues, facilitate good nutrient transfer, and promote stress shielding.…”

Biocompatibility of ABS and PLA Polymers with Dental Pulp Stem Cells Enhance Their Potential Biomedical Applications

“…Despite initial viability reduction, hDPSCs thrived by the seventh day. These results suggest that these novel scaffolds could be promising as bone substitutes capable of controlling typical severe infectious processes [ 45 ]. The possibility of prototyping with both ABS and PLA polymers allows the manufacture of scaffolds with complex geometries, both internal and external, which allows the production of infinite forms for patient care (Sears et al, 2016).…”