Cellulose, Chitosan, and Keratin Composite Materials. Controlled Drug Release

Abstract

A method was developed in which cellulose (CEL) and/or chitosan (CS) were added to keratin (KER) to enable [CEL/CS+KER] composites to have better mechanical strength and wider utilization. Butylmethylimmidazolium chloride ([BMIm+Cl–]), an ionic liquid, was used as the sole solvent, and because the [BMIm+Cl–] used was recovered, the method is green and recyclable. Fourier transform infrared spectroscopy results confirm that KER, CS, and CEL remain chemically intact in the composites. Tensile strength results expectedly show that adding CEL or CS into KER substantially increases the mechanical strength of the composites. We found that CEL, CS, and KER can encapsulate drugs such as ciprofloxacin (CPX) and then release the drug either as a single or as two- or three-component composites. Interestingly, release rates of CPX by CEL and CS either as a single or as [CEL+CS] composite are faster and independent of concentration of CS and CEL. Conversely, the release rate by KER is much slower, and when incorporated into CEL, CS, or CEL+CS, it substantially slows the rate as well. Furthermore, the reducing rate was found to correlate with the concentration of KER in the composites. KER, a protein, is known to have secondary structure, whereas CEL and CS exist only in random form. This makes KER structurally denser than CEL and CS; hence, KER releases the drug slower than CEL and CS. The results clearly indicate that drug release can be controlled and adjusted at any rate by judiciously selecting the concentration of KER in the composites. Furthermore, the fact that the [CEL+CS+KER] composite has combined properties of its components, namely, superior mechanical strength (CEL), hemostasis and bactericide (CS), and controlled drug release (KER), indicates that this novel composite can be used in ways which hitherto were not possible, e.g., as a high-performance bandage to treat chronic and ulcerous wounds.

One-Pot Synthesis of Biocompatible Silver Nanoparticle Composites from Cellulose and Keratin: Characterization and Antimicrobial Activity

“…Raw (untreated) sheep wool, obtained from a local farm, was cleaned by Soxhlet extraction using a 1:1 (v/v) acetone/ethanol mixture at 80 ± 3 °C for 48 h. The wool was then rinsed with distilled water and dried at 100 ± 1 °C for 12 h. 30 …”

“…[30][31][32]35 As shown in Scheme 1, washed wool was dissolved in BMIm + Cl -at 120 °C. Once dissolved, the solution temperature was reduced to 90 °C before CEL was added to the KER solution.…”

“…As expected, the blue spectrum of [CEL+KER] is similar to those previously observed for the [CEL+KER] composites, namely, bands at 1700-1600 and 1550 cm -1 are due to C═O stretch (amide I) and C-N stretch (amide II) vibrations and those at 1300-1200 cm -1 are from the in-phase combination of the N-H bend and C-N stretch vibrations (amide III). [30][31][32][36][37][38] Major bands between 1200 and 900 cm -1 are due to sugar ring deformations of the CEL. [30][31][32][36][37][38] The fact that the green spectrum of the [CEL+KER+Ag 0 NPs] composite is relatively similar to the blue spectrum of the [CEL+KER] composite seems to indicate that there may not be strong interaction between the Ag 0 NPs and CEL and KER in the composite.…”

“…[29][30][31][32][33][34][35] Spectroscopy [Fourier transform infrared (FTIR), near-infrared (NIR), and cross-polarization magic angle spinning (CP-MAS) 13 C NMR] results indicate that there was no chemical alteration in the structures of CEL and KER. [29][30][31][32][33][34][35] While there may be some changes in the molecular weights of CEL and KER, by accessed by following the link in the citation at the bottom of the page. Vol 8, No.…”

“…31,35 The [CEL+KER] composites obtained were found to retain unique properties of their components, namely, superior mechanical strength from CEL and controlled release of drugs by KER. [29][30][31][32][33][34][35] The information presented clearly indicates that it is possible to use NPs from changing size and morphology as well as undergoing coagulation, they can, therefore, fully retain the unique property of the AgNPs for repeated use without any complication of the reducing activity and not fully recover after each use. With these two composites, we will be able to finally address the important question that, to date, still remains unanswered, namely, the antimicrobial activity of AgNPs due to either Ag + or Ag 0 or both, and if both forms are active, which NPs have higher activity.…”