Design and synthesis of chitosan nanocomposites to produce a new generation of antimicrobial soft contact lenses
Masoud Sadeghi1 *, Abbas Azimi Khorasani1 , Hossein Bagheri2 , Maryam Erfani Haghiri3 , Siamak Zarei-Ghanavati4 , Mohsen Arefnejad5 , Parastoo Tajzadeh5 , Ahad Khosh Zaban6
- Department of Optometry, paramedical school, Mashhad University of medical sciences, Mashhad, Iran
- School of Dentistry; Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Radiology, Razavi international hospital, Mashhad, Iran
- Director of University International Office, Associate Professor of Ophthalmology, Mashhad University of medical sciences, Mashhad, Iran
- Kashmar Center of Higher Health Education, Mashhad University of Medical Sciences, Mashhad, Iran
- ranian Tissue Bank Research and Preparation Center, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
Abstract: The most significant complication of contact lens wear is microbial keratitis. Microorganisms can attach to all types of contact lens materials but soft materials are more susceptible for adhesion and colonization of microorganisms. Coating or impregnation of commercially available contact lenses with antimicrobial agents are methods to change the properties of contact lens surface that may induce physical damage on the cornea. As a natural polymer, chitosan has all the properties needed to make an ideal antimicrobial soft contact lenses.
Methods: Sol-gel method used for synthesis chitosan nanocomposite; prepared thin films characterized using FT-IR, XRD and SEM. The tensile strength, light transmittance and equilibrium water content of the nanocomposite provided by standard methods. The evaporative Spin-casting method used in order to convert the prepared nanocomposite into the form of contact lens. Contact lenses prepared from chitosan in different compositions of nanoparticles were placed in culture media along with commercial contact lenses (immersed in MPS as positive control group), and standard strains added to the culture medium. In an animal study, subcutaneous implantation test and placement of contact lens on the eye of New Zealand white rabbits were used to determine the biocompatibility of nanocomposite possessing the strongest antimicrobial activity.
Results: The results of FT-IR, XRD and SEM electron microscopy, proved that the molecular structure of nanoparticles and the way in which the bonds formed between them are homogeneous and the synthesized composition can be confirmed as nanocomposite. The tensile strength, optical transparency (90% and higher in most visible light spectra), the equilibrium water content (about 80%) and the refractive index of chitosan nanocomposite was quite good in comparison with a variety of soft contact lenses, on average. The results of the antimicrobial activity of the synthesized nanocomposite shows that the simultaneous presence of silver and zinc oxide nanoparticles, enhances the antimicrobial activity of chitosan nanocomposite. Chitosan nanocomposite has biocompatibility near the commercial contact lens (control).
Conclusion: The synthesized chitosan nanocomposite has the proper characteristics of soft contact lens materials, which can be attributed to the appropriate physical strength, good optical transparency, and sufficient oxygen permeability. This product has appropriate antimicrobial properties and good biocompatibility. More research is needed to optimize the properties mentioned above.
