Hybrid Drug Delivery Patches Based on Spherical Cellulose Nanocrystals and Colloid Titania-Synthesis and Antibacterial Properties

Abstract

Spherical cellulose nanocrystal-based hybrids grafted with titania nanoparticles were successfully produced for topical drug delivery. The conventional analytical filter paper was used as a precursor material for cellulose nanocrystals (CNC) production. Cellulose nanocrystals were extracted via a simple and quick two-step process based on first the complexation with Cu(II) solution in aqueous ammonia followed by acid hydrolysis with diluted H₂SO₄. Triclosan was selected as a model drug for complexation with titania and further introduction into the nanocellulose based composite. Obtained materials were characterized by a broad variety of microscopic, spectroscopic, and thermal analysis methods. The drug release studies showed long-term release profiles of triclosan from the titania based nanocomposite that agreed with Higuchi model. The bacterial susceptibility tests demonstrated that released triclosan retained its antibacterial activity against Escherichia coli and Staphylococcus aureus. It was found that a small amount of titania significantly improved the antibacterial activity of obtained nanocomposites, even without immobilization of model drug. Thus, the developed hybrid patches are highly promising candidates for potential application as antibacterial agents.

Keywords: bioactivity; cellulose nanocrystals; drug delivery; titania; triclosan.

Scheme 1

Synthesis route of spherical shaped nanocellulose from filter paper (PCNC sample).

Scheme 2

The preparation of dried nanocomposite film based on nanocellulose and titania nanocrystals (CNC_TiO₂ sample).

Figure 1

Morphology images obtained by AFM (a–c) and SEM (1–3) microscopy together with visual images, particle size distribution (theoretically fitted using Gaussian distribution function) (d–f) of the obtained samples.

Figure 2

X-ray diffraction patterns of the obtained samples.

Figure 3

FT-IR spectra of PCNC (a), CNC_TR (b), CNC_TiO₂ (c), and CNC_TiO₂_TR (d).

Figure 4

Molecular structure of compound 1 (a) and molecular structure of compound 2 (b).

Figure 5

TGA (a) and DTG (b) curves of the obtained nanocomposites.

Figure 6

The tensile–strain curves of the films (a) PCNC, (b) CNC_TiO₂, and (c) CNC_TiO₂_TR.

Figure 7

The cumulative release (%) of triclosan from CNC_TR (left) and CNC_TiO₂_TR (right).

Figure 8

Kinetics study for the release of triclosan from CNC_TR(1) and CNC_TiO₂_TR(2): Zero order (a); First order (b); Higuchi (c); Hixon–Crowell (d) and Korsmeyer–Peppas (e) kinetic models.