Magnetosome mediated oral Insulin delivery and its possible use in diabetes management

Therapeutic Innovations in Nanomedicine: Exploring the Potential of Magnetotactic Bacteria and Bacterial Magnetosomes

Nanotechnology has emerged as a revolutionary domain with diverse applications in medicine, and one of the noteworthy developments is the exploration of bacterial magnetosomes acquired from magnetotactic bacteria (MTB) for therapeutic purposes. The demand for natural nanomaterials in the biomedical field is continuously increasing due to their biocompatibility and eco-friendly nature. MTB produces uniform, well-ordered magnetic nanoparticles inside the magnetosomes, drawing attention due to their unique and remarkable features. MTB and magnetosomes have gained popularity in cancer treatment and diagnosis, especially in magnetic resonance imaging. Distinctive features highlighted include advancements in extraction, characterization, and functionalization techniques, alongside breakthroughs in utilizing MTB-based magnetosomes as contrast agents in imaging, biocompatible drug carriers, and tools for minimally invasive therapies. The biocompatible nature, functionalizing of the surface of bacterial magnetosomes, and response to the external magnetic field make them a potential candidate for the theragnostic purpose of MTB and magnetosomes. In the present review, emphasis has been given to the foundation of magnetosomes at a genetic level, mass production of magnetosomes, etc. Further authors have reviewed the various functionalization methods of the magnetosomes for cancer treatment. Finally, the authors have reviewed the recent advancements in MTB and magnetosome-based cancer detection, diagnosis, and treatment. Challenges such as scalability, long-term safety, and clinical translation are also discussed, presenting a roadmap for future research exploiting MTBs and magnetosomes' unique properties.

Nanoparticle and microparticle-based systems for enhanced oral insulin delivery: A systematic review and meta-analysis

Diabetes mellitus (DM) prevalence is rising worldwide. Current therapies comprising subcutaneous insulin injections can cause adverse effects such as lipodystrophy, local reactions like redness and swelling, fluid retention, and allergic reactions. Nanoparticle carriers for oral insulin are groundbreaking compared to existing methods because they are non-invasive treatments, showing operational convenience, controlled release profile, and ability to simulate the physiological delivery route into the bloodstream. These systems improve patient adherence and have demonstrated the potential to lower blood glucose levels in DM. We present a systematic review and meta-analysis aimed at compiling relevant data to pave the way for developing innovative nano- and microparticles for the oral delivery of insulin. Our analysis of 85 articles revealed that the diminution of glucose levels is not proportional to the administered insulin dosage, which ranged from 1 to 120 International Units (IU). The meta-analysis data indicated that 25 IU of encapsulated porcine insulin did not produce a statistically significant outcome (p = 0.93). In contrast, a dosage of 30 IU was efficacious in eliciting an optimal hypoglycemic effect compared to excipient controls. Parameters such as a high degree of encapsulation (~ 90%), particle size (200-400 nm), and polydispersity index (0.086-0.3) are all associated with lower blood glucose levels. These parameters were also significant in the linear regression analysis. Among the excipients employed, chitosan emerged as a prevalent excipient in formulations due to its biocompatible and biodegradable properties and its ability to establish stable polymeric matrices. Even though oral insulin administration is a promising therapeutic method, it cannot guarantee preclinical safety and therapeutic efficacy yet in regulating glucose levels in diabetic conditions.

Investigation of pharmacokinetics and immunogenicity of magnetosomes

Magnetosomes are iron oxide or iron sulphide nano-sized particles surrounded by a lipid bilayer synthesised by a group of bacteria known as magnetotactic bacteria (MTB). Magnetosomes have become a promising candidate for biomedical applications and could be potentially used as a drug-carrier. However, pharmacokinetics and immunogenicity of the magnetosomes have not been understood yet which preclude its clinical applications. Herein, we investigated the pharmacokinetics of magnetosomes including Absorption, Distribution, Metabolism, and Elimination (ADME) along with its immunogenicity in vitro and in vivo. The magnetosomes were conjugated with fluorescein isothiocyanate (Mag-FITC) and their conjugation was confirmed through fluorescence microscopy and its absorption in HeLa cell lines was evaluated using flow cytometry analysis. The results revealed a maximum cell uptake of 97% at 200 µg/mL concentration. Further, the biodistribution of Mag-FITC was investigated in vivo by a bioimaging system using BALB/c mice as a subject at different time intervals. The Mag-FITC neither induced death nor physical distress and the same was eliminated post 36 h of injection with meagre intensities left behind. The metabolism and elimination analysis were assessed to detect the iron overload which revealed that magnetosomes were entirely metabolised within 48-h interval. Furthermore, the histopathology and serum analysis reveal no histological damage with the absence of any abnormal biochemical parameters. The results support our study that magnetosomes were completely removed from the blood circulation within 48-h time interval. Moreover, the immunogenicity analysis has shown that magnetosomes do not induce any inflammation as indicated by reduced peaks of immune markers such as IL 1β, IL 2, IL 6, IL8, IFN γ, and TNF α estimated through Indirect ELISA. The normal behaviour of animals with the absence of acute or chronic toxicities in any organs declares that magnetosomes are safe to be injected. This shows that magnetosomes are benign for biological systems enrouting towards beneficial biomedical applications. Therefore, this study will advance the understanding and application of magnetosomes for clinical purposes.

Exploiting Apical Sodium-Dependent Bile Acid Transporter (ASBT)-Mediated Endocytosis with Multi-Functional Deoxycholic Acid Grafted Alginate Amide Nanoparticles as an Oral Insulin Delivery System

OBJECTIVE

Oral administration of insulin is a potential candidate for managing diabetes. However, it is obstructed by the gastrointestinal tract barriers resulting in negligible oral bioavailability.

METHODS

This investigation presents a novel nanocarrier platform designed to address these challenges. In this regard, the process involved amination of sodium alginate by ethylene diamine, followed by its conjugation with deoxycholic acid.

RESULTS

The resulting DCA@Alg@INS nanocarrier revealed a significantly high insulin loading content of 63.6 ± 1.03% and encapsulation efficiency of 87.6 ± 3.84%, with a particle size of 206 nm and zeta potentials of -3 mV. In vitro studies showed sustained and pH-dependent release profiles of insulin from nanoparticles. In vitro cellular studies, confocal laser scanning microscopy and flow cytometry analysis confirmed the successful attachment and internalization of DCA@Alg@INS nanoparticles in Caco-2 cells. Furthermore, the DCA@Alg@INS demonstrated a superior capacity for cellular uptake and permeability coefficient relative to the insulin solution, exhibiting sixfold and 4.94-fold enhancement, respectively. According to the uptake mechanism studies, the results indicated that DCA@Alg@INS was mostly transported through an energy-dependent active pathway since the uptake of DCA@Alg@INS by cells was significantly reduced in the presence of NaN3 by ~ 92% and at a low temperature of 4°C by ~ 94%.

CONCLUSIONS

Given the significance of administering insulin through oral route, deoxycholic acid-modified alginate nanoparticles present a viable option to surmount various obstacles presented by the gastrointestinal.

Evaluation of cell disruption technologies on magnetosome chain length and aggregation behaviour from Magnetospirillum gryphiswaldense MSR-1

Magnetosomes are biologically-derived magnetic nanoparticles (MNPs) naturally produced by magnetotactic bacteria (MTB). Due to their distinctive characteristics, such as narrow size distribution and high biocompatibility, magnetosomes represent an attractive alternative to existing commercially-available chemically-synthesized MNPs. However, to extract magnetosomes from the bacteria, a cell disruption step is required. In this study, a systematic comparison between three disruption techniques (enzymatic treatment, probe sonication and high-pressure homogenization) was carried out to study their effect on the chain length, integrity and aggregation state of magnetosomes isolated from Magnetospirillum gryphiswaldense MSR-1 cells. Experimental results revealed that all three methodologies show high cell disruption yields (>89%). Transmission electron microscopy (TEM), dynamic light scattering (DLS) and, for the first time, nano-flow cytometry (nFCM) were employed to characterize magnetosome preparations after purification. TEM and DLS showed that high-pressure homogenization resulted in optimal conservation of chain integrity, whereas enzymatic treatment caused higher chain cleavage. The data obtained suggest that nFCM is best suited to characterize single membrane-wrapped magnetosomes, which can be particularly useful for applications that require the use of individual magnetosomes. Magnetosomes were also successfully labelled (>90%) with the fluorescent CellMask™ Deep Red membrane stain and analysed by nFCM, demonstrating the promising capacity of this technique as a rapid analytical tool for magnetosome quality assurance. The results of this work contribute to the future development of a robust magnetosome production platform.

Biomineralization and biotechnological applications of bacterial magnetosomes

Magnetosomes intracellularly biomineralized by Magnetotactic bacteria (MTB) are membrane-enveloped nanoparticles of the magnetic minerals magnetite (Fe₃O₄) or greigite (Fe₃S₄). MTB thrive in oxic-anoxic interface and exhibit magnetotaxis due to the presence of magnetosomes. Because of the unique characteristic and bionavigation inspiration of magnetosomes, MTB has been a subject of study focused on by biologists, medical pharmacologists, geologists, and physicists since the discovery. We herein first briefly review the features of MTB and magnetosomes. The recent insights into the process and mechanism for magnetosome biomineralization including iron uptake, magnetosome membrane invagination, iron mineralization and magnetosome chain assembly are summarized in detail. Additionally, the current research progress in biotechnological applications of magnetosomes is also elucidated, such as drug delivery, MRI image contrast, magnetic hyperthermia, wastewater treatment, and cell separation. This review would expand our understanding of biomineralization and biotechnological applications of bacterial magnetosomes.

Preparation, characterization, and in vitro release kinetics of doxorubicin-loaded magnetosomes

The doxorubicin (DOX) was successfully coupled to the magnetosomes from Acidithiobacillus ferrooxidans (At. ferrooxidans) by genipin bridging. The parameters (magnetosome concentration, DOX concentration, genipin concentration-, and cross-link time) expected for temperature significantly influenced the coupling rate. Bacterial magnetosome-doxorubicin complexes (BMDCs) were characterized by transmission electron microscope (TEM), particle size analyzer and Fourier transform infrared spectroscopy. Results indicated that BMDCs exhibited a mean particle size of 83.98 mm and displayed a negative charge. The chemical reaction occurring between CO and NH group and the physical adsorption predominated by electrostatic interaction were found to involve in coupling. BMDCs can release 40% of DOX in simulated gastrointestinal conditions within 38 h. Kinetic models including Higuchi, Korsmeyer-Peppas, Zero order, First order, Hixon-Crowell, Baker-Lonsdale, and Weibull and Gompertz were utilized to explore the release mechanism of DOX from BMDCs. All models were found to fit well (r² ≥ 0.8144) with the release data and the Gompertz was the best fit model (r² = 0.9742), implying that the complex mechanisms involving Fickian and Gompertz diffusion contributed to the release. These findings suggested that magnetosomes from At. ferrooxidans have great potential applications in biomedical and clinical fields as the carrier of target drug delivery systems in the future.