Triple Antibiotic Polymer Nanofibers for Intracanal Drug Delivery: Effects on Dual Species Biofilm and Cell Function

Abstract

Introduction Root canal disinfection and the establishment of an intracanal microenvironment conducive to the proliferation/differentiation of stem cells play a significant role in regenerative endodontics. This study was designed to (1) investigate the antimicrobial efficacy of triple antibiotic–containing nanofibers against a dual-species biofilm and (2) evaluate the ability of dental pulp stem cells (DPSCs) to adhere to and proliferate on dentin upon nanofiber exposure. Methods Seven-day-old dual-species biofilm established on dentin specimens was exposed for 3 days to the following: saline (control), antibiotic-free nanofibers (control), and triple antibiotic–containing nanofibers or a saturated triple antibiotic paste (TAP) solution (50 mg/mL in phosphate buffer solution). Bacterial viability was assessed using the LIVE/DEAD assay (Molecular Probes, Inc, Eugene, OR) and confocal laser scanning microscopy. For cyto-compatibility studies, dentin specimens after nanofiber or TAP (1 g/mL in phosphate buffer solution) exposure were evaluated for cell adhesion and spreading by actin-phalloidin staining. DPSC proliferation was assessed on days 1, 3, and 7. Statistics were performed, and significance was set at the 5% level. Results Confocal laser scanning microscopy showed significant bacterial death upon antibiotic-containing nanofiber exposure, differing significantly (P < .05) from antibiotic-free fibers and the control (saline). DPSCs showed enhanced adhesion/spreading on dentin specimens treated with antibiotic-containing nanofibers when compared with its TAP counterparts. The DPSC proliferation rate was similar on days 1 and 3 in antibiotic-free nanofibers, triple antibiotic–containing nanofibers, and TAP-treated dentin. Proliferation was higher (9-fold) on dentin treated with antibiotic-containing nanofibers on day 7 compared with TAP. Conclusions Triple antibiotic–containing polymer nanofibers led to significant bacterial death, whereas they did not affect DPSC attachment and proliferation on dentin.

Antimicrobial Efficacy of Triple Antibiotic–eluting Polymer Nanofibers against Multispecies Biofilm

“…Due to the aforementioned concerns, recent research has focused on the development of cell-friendly intracanal drug delivery systems (20–31). Electrospinning is known to be a straightforward nanotechnology-based technique capable of fabricating not only tissue scaffolds for regenerative medicine, but also antibiotic-eluting polymer nanofibers for use in drug delivery (10, 21–25, 27–31).…”

Advanced Scaffolds for Dental Pulp and Periodontal Regeneration

“…3–5 In light of this, a biocompatible nanofiber-based intracanal drug delivery system has been proposed as a means to create a bacteria-free environment favorable to tissue regeneration. 3,12–20 In brief, a polymer solution loaded with the chosen antibiotic(s) at the desired concentration needs to be prepared. 3,12, 21 Following that, by adjusting electrospinning parameters (e.g., flow rate, field strength, etc.…”

“…1) holds great clinical potential, as it will guarantee the release of antibiotics onto the dentinal walls where microbial biofilm has been found to be present. 3,12,14–16,18–20,62 As an example, triple (MET, CIP, and MINO) antibiotic-eluting nanofibers were developed and tested for antimicrobial efficacy against a dual species bacterial biofilm. 20 Infected dentin exposed to the triple-antibiotic-eluting nanofibers revealed significant bacterial death based on confocal laser scanning microscopy data (Fig.…”

“…1). Numerous studies 3,12–16,18–20 have been published and provided critical information to test the clinical efficacy of 3D tubular-shaped antibiotic-eluting nanofibers using animal models of periapical disease (Fig. 1).…”

“…4 To circumvent the characteristic toxicity associated with commonly used antibiotic pastes and sodium hypochlorite, a more biocompatible strategy has recently been developed by our laboratory. A series of studies 3,12–20 have stressed the practicality and translational prospects of three-dimensional (3D) easy-to-fit antibiotic-eluting nanofibers as a localized, intracanal drug delivery strategy that, combined with injectable scaffolds, enriched or not with stem cells and/or growth factors (GFs), may lead to an increased likelihood of achieving predictable dental pulp regeneration in humans.…”