Bioactive Icariin/β-CD-IC/Bacterial Cellulose with Enhanced Biomedical Potential

Abstract

A "super" bioactive antibacterial hydrogel, Icariin-β-CD-inclusion complex/Bacterial cellulose and an equally capable counterpart Icariin-Bacterial cellulose (ICBC) were successfully produced with excellent antioxidant properties. The highly porous hydrogels demonstrated very high fluid/liquid absorption capability and were functionally active as Fourier Transform Infrared Spectrometer (FTIR) test confirmed the existence of abundant hydroxyls (-OH stretching), carboxylic acids (-CH₂/C-O stretching), Alkyne/nitrile (C≡C/C≡N stretching with triple bonds) and phenol (C-H/N-O symmetric stretching) functional groups. Scanning electron microscope (SEM) and X-ray diffraction (XRD) tests confirmed a successful β-CD-inclusion complexation with Icariin with a great potential for sustained and controlled drug release. In vitro drug release test results indicated a systemic and controlled release of the drug (Icariin) from the internal cavities of the β-CD inclusion complex incorporated inside the BC matrix with high Icariin (drug) release rates. Impressive inactivation rates against Gram-negative bacteria Escherichia coli ATCC 8099 and gram-positive bacteria Staphylococcus aureus ATCC 6538; >99.19% and >98.89% respectively were recorded, as the materials proved to be non-toxic on L929 cells in the in vitro cytotoxicity test results. The materials with promising versatile multipurpose administration of Icariin for wound dressing (as wound dressers), can also be executed as implants for tissue regeneration, as well as face-mask for cosmetic purposes.

Keywords: Icariin-β-CD inclusion complex; antibacterial; antioxidants; bacterial cellulose; biomedical applications; controlled-drug release.

Scheme 1

Illustration of the preparation of Icariin/beta-cyclodextrin inclusion complex/BC (IC/P/BC).

Scheme 2

Illustration of the Icariin/βC (ICr/BC) in situ preparation.

Figure 1

Swelling performance of (A) 0.1 M NaCl solution, (B) DI water, (C) PBS solution of the freeze-dried hydrogel composites. (D) Porosity% of samples.

Figure 2

SEM images of (A) Pure BC, (A-I) ICrBC (B) IC/P/BC 50 (red arrows in both (B,C) indicate the inclusion complexed icariin within the β-CD cavities showing the typical block-like appearance, (C) IC/P/BC 100 (insert: image of pure β-CD inclusion complex block-like units with a yellow arrow), (D) IC/BC 50 (pink arrows in both (D,E) indicate aggregated chips potentially with icariin, (E) IC/BC 100. (F) Molecular structures and Inclusion complexation mode of Icariin/β-CD-IC/BC (coded as IC/P/BC) Hydrogels.

Figure 3

(A) FT-IR spectra of drug-loaded fibrous membranes and raw material. (B) XRD patterns of drug-loaded fibrous membranes and raw materials.

Figure 4

DSC curves of (A) Pure BC; (B) ICrBC membrane; (C) ICPBC 50 membrane; (D) ICPBC 100 membrane; (E) ICBC 50 membrane; (F) ICBC 100 membrane.

Figure 5

Typical stress-strain curves of as-prepared fibrous membranes.

Figure 6

In vitro release profiles for Pure BC, and the drug loaded samples; ICBC, ICPBC and ICrBC.

Figure 7

Survival and inactivation rates (%) of the membranes against E. coli and S. aureus.

Figure 8

(A) DPPH Radical Scavenging activity (Blank, BC and drug loaded samples) and (B) antioxidant proficiency per icariin dosage as a function of time; involving BC, ICBC 50 & 100 mg, ICPBC 50 & 100 mg and ICrBC samples.

Figure 9

In vitro cytotoxicity results; Cell viability when contacting with membrane samples.