In Situ Strategy to Encapsulate Antibiotics in a Bioinspired CaCO₃ Structure Enabling pH-Sensitive Drug Release Apt for Therapeutic and Imaging Applications

Abstract

Herein we demonstrate a bioinspired method involving macromolecular assembly of anionic polypeptide with cationic peptide-oligomer that allows for in situ encapsulation of antibiotics like tetracycline in CaCO3 microstructure. In a single step one-pot process, the encapsulation of the drug occurs under desirable environmentally benign conditions resulting in drug loaded CaCO3 microspheres. While this tetracycline-loaded sample exhibits pH dependent in vitro drug-release profile and excellent antibacterial activity, the encapsulated drug or the dye-conjugated peptide emits fluorescence suitable for optical imaging and detection, thereby making it a multitasking material. The efficacy of tetracycline loaded calcium carbonate microspheres as pH dependent drug delivery vehicles is further substantiated by performing cell viability experiments using normal and cancer cell lines (in vitro). Interestingly, the pH-dependent drug release enables selective cytotoxicity toward cancer cell lines as compared to the normal cells, thus having the potential for further development of therapeutic applications.

The mechanism of catalase loading into porous vaterite CaCO3 crystals by co-synthesis

“…Besides this, the high loading capacity of CaCO 3 crystals provides an opportunity for slow long-term controlled release, which is of high interest for therapeutic applications. 65,66 A high content of the loaded protein would give an option to reduce the number of carriers for protein delivery (the crystals or other carriers assembled using the crystal, e.g. microcapsules).…”

Porous Inorganic Carriers Based on Silica, Calcium Carbonate and Calcium Phosphate for Controlled/Modulated Drug Delivery: Fresh Outlook and Future Perspectives

“…It possesses unique advantages due to their biocompatibility and the ability for loading different therapeutic agents. Studies show that CaCO 3 nano/microparticles can be used as vectors to deliver various biological substances such as drugs [143,148], proteins [111,143,147,149], peptides [150,151] and genes [132,152]. Due to high biocompatibility, biodegradability, and pH sensitive features, vaterite and ACC show promising potential for the development of the drug delivery system for cancer treatment [143,148].…”

“…The antibacterial activity and pH-dependent drug release have been observed for CaCO 3 microstructures containing tetracycline-entrapped polypeptides [150]. It has been shown that the encapsulated drug or the dye-conjugated peptide emits fluorescence suitable for optical imaging and detection, thereby making it a multitasking material.…”

Approaches based on passive and active antibacterial coating on titanium to achieve antibacterial activity

“…Using this method, the antibacterial agents will not be released until bacteria are present. Many “smart release” methods have been applied in anti‐cancer treatment, taking advantage of the acidic environment inside tumor cells . Because bacteria favor a relatively acidic microenvironment, the pH‐sensitive smart release of antibacterial agents can be conducted locally; in contrast, if no bacteria are present, antibacterial agents will not be released in vivo.…”