Thermal and microwave synthesized SPIONs: Energy effects on the efficiency of nano drug carriers

Enhanced Bacterial Cuproptosis-Like Death via Reversal of Hypoxia Microenvironment for Biofilm Infection Treatment

A recently emerging cell death pathway, known as copper-induced cell death, has demonstrated significant potential for treating infections. Existing research suggests that cells utilizing aerobic respiration, as opposed to those reliant on glycolysis, exhibit greater sensitivity to copper-induced death. Herein, a MnO2-loaded copper metal-organic frameworks platform is developed denoted as MCM, to enhance bacterial cuproptosis-like death via the remodeling of bacterial respiratory metabolism. The reversal of hypoxic microenvironments induced a cascade of responses, encompassing the reactivation of suppressed immune responses and the promotion of osteogenesis and angiogenesis. Initially, MCM catalyzed O2 production, alleviating hypoxia within the biofilm and inducing a transition in bacterial respiration mode from glycolysis to aerobic respiration. Subsequently, the sensitized bacteria, characterized by enhanced tricarboxylic acid cycle activity, underwent cuproptosis-like death owing to increased copper concentrations and aggregated intracellular dihydrolipoamide S-acetyltransferase (DLAT). The disruption of hypoxia also stimulated suppressed dendritic cells and macrophages, thereby strengthening their antimicrobial activity through chemotaxis and phagocytosis. Moreover, the nutritional effects of copper elements, coupled with hypoxia alleviation, synergistically facilitated the regeneration of bones and blood vessels. Overall, reshaping the infection microenvironment to enhance cuproptosis-like cell death presents a promising avenue for eradicating biofilms.

Modulating the Effect of β-Sitosterol Conjugated with Magnetic Nanocarriers to Inhibit EGFR and Met Receptor Cross Talk

The cross-talk between the EGFR (Epidermal Growth Factor Receptor) and MET (Hepatocyte Growth Factor Receptor) poses a significant challenge in the field of molecular signaling. Their intricate interplay leads to dysregulation and contributes to cancer progression and therapeutic resistance. β-Sitosterol (BS), a plant sterol with promising anticancer properties, shows increased research on its potential as a chemopreventive agent. However, significant modifications are required to deliver BS in cancer cells due to its lower efficacy. The present work aims to design a carrier-mediated delivery system specifically targeting cancer cells with EGFR and MET receptor cross-talk. Surface modification of BS was performed with superparamagnetic iron oxide nanoparticles (SPIONs), polyethylene glycol (PEG), and poly(N-isopropylacrylamide) (PNIPAM) to enhance the delivery of BS at the target site. BS was conjugated with SPIONs (BS-S), PNIPAM (BS-SP), PEG, and PNIPAM (BS-SPP) polymers, respectively, and the conjugated complexes were characterized. Results showed an increase in size, stability, and monodispersity in the following order, BS-S, BS-SP, and BS-SPP. The drug encapsulation efficiency was observed to be highest in BS-SPP (82.5%), compared to BS-S (61%) and BS-SP (74.9%). Sustained drug release was achieved in both BS-SP (82.6%) and BS-SPP (83%). The IC 50 value of BS, BS-S, BS-SP, and BS-SPP towards MCF 7 was 242 µg/mL,197 µg/mL, 168 µg/mL, and 149 µg/mL, HEPG2 was 274 µg/mL, 261 µg/mL, 233 µg/mL and 207 µg/mL and NCIH 460 was 191 µg/mL, 185 µg/mL, 175 and 164 µg/mL, indicating highest inhibition towards NCIH 460 cells. Our results conclude that β-sitosterol conjugated with SPION, PEG, and PNIPAM could be a potential targeted therapy in inhibiting EGFR and MET receptor-expressing cancer cells.

SPIONs Conjugate Supported Anticancer Drug Doxorubicin's Delivery: Current Status, Challenges, and Prospects

Considerable efforts have been directed towards development of nano-structured carriers to overcome the limitations of anticancer drug, doxorubicin's, delivery to various cancer sites. The drug's severe toxicity to cardio and hepatic systems, low therapeutic outcomes, inappropriate dose-demands, metastatic and general resistance, together with non-selectivity of the drug have led to the development of superparamagnetic iron oxide nanoparticles (SPIONs)-based drug delivery modules. Nano-scale polymeric co-encapsulation of the drug, doxorubicin, with SPIONs, the SPIONs surface end-groups' cappings with small molecular entities, as well as structural modifications of the SPIONs' surface-located functional end-groups, to attach the doxorubicin, have been achieved through chemical bonding by conjugation and cross-linking of natural and synthetic polymers, attachments of SPIONs made directly to the non-polymeric entities, and attachments made through mediation of molecular-spacer as well as non-spacer mediated attachments of several types of chemical entities, together with the physico-chemical bondings of the moieties, e.g., peptides, proteins, antibodies, antigens, aptamers, glycoproteins, and enzymes, etc. to the SPIONs which are capable of targeting multiple kinds of cancerous sites, have provided stable and functional SPIONs-based nano-carriers suitable for the systemic, and in vitro deliveries, together with being suitable for other biomedical/biotechnical applications. Together with the SPIONs inherent properties, and ability to respond to magnetic resonance, fluorescence-directed, dual-module, and molecular-level tumor imaging; as well as multi-modular cancer cell targeting; magnetic-field-inducible drug-elution capacity, and the SPIONs' magnetometry-led feasibility to reach cancer action sites have made sensing, imaging, and drug and other payloads deliveries to cancerous sites for cancer treatment a viable option. Innovations in the preparation of SPIONs-based delivery modules, as biocompatible carriers; development of delivery route modalities; approaches to enhancing their drug delivery-cum-bioavailability have explicitly established the SPIONs' versatility for oncological theranostics and imaging. The current review outlines the development of various SPIONs-based nano-carriers for targeted doxorubicin delivery to different cancer sites through multiple methods, modalities, and materials, wherein high-potential nano-structured platforms have been conceptualized, developed, and tested for, both, in vivo and in vitro conditions. The current state of the knowledge in this arena have provided definite dose-control, site-specificity, stability, transport feasibility, and effective onsite drug de-loading, however, with certain limitations, and these shortcomings have opened the field for further advancements by identifying the bottlenecks, suggestive and plausible remediation, as well as more clear directions for future development.

Nanozyme for tumor therapy: Surface modification matters

As the next generation of artificial enzymes, nanozymes have shown unique properties compared to its natural counterparts, such as stability in harsh environment, low cost, and ease of production and modification, paving the way for its biomedical applications. Among them, tumor catalytic therapy mediated by the generation of reactive oxygen species (ROS) has made great progress mainly from the peroxidase-like activity of nanozymes. Fe₃O₄ nanozymes, the earliest type of nanomaterial discovered to possess peroxidase-like activity, has consequently received wide attention for tumor therapy due to its ROS generation ability and tumor cell killing ability. However, inconsistent results of cytotoxicity were observed between different reports, and some even showed the scavenging of ROS in some cases. By collectively studying these inconsistent outcomes, we raise the question whether surface modification of Fe₃O₄ nanozymes, either through affecting peroxidase activity or by affecting the biodistribution and intracellular fate, play an important role in its therapeutic effects. This review will go over the fundamental catalytic mechanisms of Fe₃O₄ nanozymes and recent advances in tumor catalytic therapy, and discuss the importance of surface modification. Employing Fe₃O₄ nanozymes as an example, we hope to provide an outlook on the improvement of nanozyme-based antitumor activity.

Urchin-like Hydroxyapatite/Graphene Hollow Microspheres as pH-Responsive Bone Drug Carriers

Hydroxyapatite (HA) is the main inorganic component of human bones and teeth. It has good biocompatibility and bioactivity, which promotes its good application prospects in the field of bone drug carriers. In this study, tetraethylenepentamine-graphene (rGO-TEPA)/CaCO₃:HA composite microspheres were prepared via microwave hydrothermal synthesis using rGO-TEPA/CaCO₃ solid microspheres as intermediates. Furthermore, the incompletely transformed CaCO₃ was removed by soaking in a citric acid buffer to obtain rGO-TEPA/HA hollow composite microspheres. The two types of as-prepared composite microspheres exhibited sea urchin-like structures, large BET surface areas, and good dispersibility. Mouse preosteoblast cells (MC3T3-E1) were used for in vitro cytotoxicity experiments. The in vitro cell viability test showed that the two composite drug carriers exhibited noncytotoxicity. Moreover, the doxorubicin (DOX) loading and releasing investigations revealed that the two types of prepared carriers had mild storage-release behaviors and good pH responsiveness. Hence, these rGO-TEPA/HA hollow microspheres have promising applications as bone drug carriers.