Controlled assembly of superparamagnetic iron oxide nanoparticle into nanoliposome for Pickering emulsion preparation.

There has been a surge in effort in the development of various solid nanoparticles as Pickering emulsion stabilizers in the past decades. Regardless, the exploration of stabilizers that simultaneously stabilize and deliver bioactive has been limited. For this, liposomes with amphiphilic nature have been introduced as Pickering emulsion stabilizers but these nano-sized vesicles lack targeting specificity. Therefore in this study, superparamagnetic iron oxide nanoparticles (SPION) encapsulated within liposomes (MLP) were used as Pickering emulsion stabilizers to prepare pH and magnetic-responsive Pickering emulsions. A stable MLP-stabilized Pickering emulsion formulation was established by varying the MLP pH, concentration, and oil loading during the emulsification process. The primary stabilization mechanism of the emulsion under pH variation was identified to be largely associated with the MLP phosphate group deprotonation. When subjected to sequential pH adjustment to imitate the gastrointestinal digestion pH environment, a recovery in Pickering emulsion integrity was observed as the pH changes from acidic to alkaline. By incorporating SPION, the Pickering emulsion can be guided to the targeted site under the influence of a magnetic field without compromising emulsion stability. Overall, the results demonstrated the potential of MLP-stabilized Pickering emulsion as a dual pH- and magnetic-responsive drug delivery carrier with the ability to co-encapsulate hydrophobic and hydrophilic bioactive.

Stimuli-responsive nanoassemblies for targeted delivery against tumor and its microenvironment.

Despite the emergence of various cancer treatments, such as surgery, chemotherapy, radiotherapy, and immunotherapy, their use remains restricted owing to their limited tumor elimination efficacy and side effects. The use of nanoassemblies as delivery systems in nanomedicine for tumor diagnosis and therapy is flourishing. These nanoassemblies can be designed to have various shapes, sizes, and surface charges to meet the requirements of different applications. It is crucial for nanoassemblies to have enhanced delivery of payloads while inducing minimal to no toxicity to healthy tissues. In this review, stimuli-responsive nanoassemblies capable of combating the tumor microenvironment (TME) are discussed. First, various TME characteristics, such as hypoxia, oxidoreduction, adenosine triphosphate (ATP) elevation, and acidic TME, are described. Subsequently, the unique characteristics of the vascular and stromal TME are differentiated, and multiple barriers that have to be overcome are discussed. Furthermore, strategies to overcome these barriers for successful drug delivery to the targeted site are reviewed and summarized. In conclusion, the possible challenges and prospects of using these nanoassemblies for tumor-targeted delivery are discussed. This review aims at inspiring researchers to develop stimuli-responsive nanoassemblies for tumor-targeted delivery for clinical applications.

Stimuli-controllable iron oxide nanoparticle assemblies: Design, manipulation and bio-applications.

Despite its wide establishment over the years, iron oxide nanoparticle (IONP) still draws extensive interest in the biomedical fields due to its biocompatibility, biodegradability, magnetivity and surface tunable properties. IONP has been used for the MRI, magnetic targeting, drug delivery and hyperthermia of various diseases. However, their poor stability, low diagnostic sensitivity and low disease-specificity have resulted in unsatisfying diagnostic and therapeutic outputs. The surface functionalization of IONP with biocompatible and colloidally stable components appears to be promising to improve its circulation and colloidal stability. Importantly, through surface functionalization with designated functional components, IONP-based assemblies with multiple stimuli-responsivity could be formed to achieve an accurate and efficient delivery of IONP to disease sites for an improved disease diagnosis and therapy. In this work, we first described the design of biocompatible and stable IONP assemblies. Further, their stimuli-driven manipulation strategies are reviewed. Next, the utilization of IONP assemblies for disease diagnosis, therapy and imaging-guided therapy are discussed. Then, the potential toxicity of IONPs and their clinical usages are described. Finally, the intrinsic challenges and future outlooks of IONP assemblies are commented. This review provides recent insights into IONP assemblies, which could inspire researchers on the future development of multi-responsive and disease-targetable nanoassemblies for biomedical utilization.