Nanomaterials for antibacterial and tissue regeneration applications

Abstract

Nanoparticulate systems have been employed for diagnostics, drug delivery, therapeutics, and tissue engineering applications. Nanoparticles with intrinsic antibacterial activity have shown promise in treating bacterial infections and combating the antimicrobial resistance (AMR) but the threat remains due to the ever-evolving biofilm. Ophthalmic drug delivery is challenging owing to the anatomical barriers present in eyes. Majority of marketed ophthalmic formulations are eye drops, which fail to overcome these barriers and, therefore, exhibit poor bioavailability. Altered wound healing is a major challenge faced by both developed and developing nations. Biofilm formation has been identified as one of the causative factors for the progression of chronic wounds as well as drug resistance. Osteoporosis is a chronic bone disorder characterized by the decreased bone mass, leading to brittle bones and fractures. Oxidative stress has been identified as the most profound trigger for the initiation and progression of osteoporosis. Current treatment strategies do not induce new bone formation and fail to address high level of reactive oxygen species (ROS). To overcome the challenges in the field, we have developed and evaluated nanomaterials to treat ocular bacterial infections, chronic wounds, and osteoporosis. The present thesis is arranged into five chapters, where Chapter 1 is introductory and includes the exhaustive literature survey, the definition of problem, and the specific objectives of this work. In Chapter 2, we have included the development and evaluation of ciprofloxacin-loaded polymeric nanoparticles of chitosan/lecithin for the treatment of ocular bacterial infections. The nanoparticles were prepared using ion gelation method and characterized, and their antibacterial properties were investigated against P. aeruginosa and S. aureus along with their cell compatible and mucoadhesive characteristics. The nanoparticles showed strong potential in treating ocular bacterial infections. Chapter 3 discusses the fabrication and evaluation of functionalized, silica ceria nanocomposite, as an antibiotic-free system, to treat biofilms. The antioxidant activity, positive haloperoxidase-mimetic property, broad-spectrum antibacterial activities against S. aureus and E. coli, and antibiofilm activities were investigated along with its cytocompatibility (cell proliferative), hemocompatibility, and wound healing ability. The functionalized silica ceria nanocomposite showed a strong potential in chronic wound healing applications. In Chapter 4, we have investigated the potential of a thiolated, bioactive mesoporous silica nanoparticles to treat osteoporosis. The nanoparticles were fabricated and surface functionalized post-synthesis with thiol groups and its antioxidant activity, ability to neutralize reactive oxygen species formed in cells and provide protection against ROS-induced cell damage, cell compatibility, calcium deposition, and osteogenesis were investigated. The nanomaterial was found to be regenerative in nature, and it showed a strong potential as a complementary and an alternate treatment for osteoporosis along with the standard therapy. The conclusions, contribution to the field, and perspectives of this work has been discussed in Chapter 5.