Nanotechnology has an increasing impact and a great potential in various biological and medical applications. Magnetic nanoparticles (MNPs) stand out for their unique properties, a reason why they have a varied spectrum of applicability in different sectors of activity; in this paper we focus on the medical field. Magnetotactic bacteria (MTB) are a group of Gram-negative prokaryotes that migrate in one direction or another under the influence of an external magnetic field and are a category of microorganisms that constitutively perform the biomineralization of magnetic nanoparticles in the cytoplasm. This review focuses on the general and particular characteristics of magnetotactic bacteria in close correlation with their utility in the medical field, starting with the medical applications of magnetic nanoparticles and arriving at the potential role in nanomedicine of MNPs extracted from MTB.

Microorganisms are transforming the way we address sustainability across agriculture, food production, waste remediation, bioenergy, and industrial bioprocessing, offering novel solutions for the food systems of tomorrow. This systematic review examines literature from the last twenty years in order to identify key advances, challenges, and future directions in harnessing microbial systems for sustainable applications, especially those underpinning a resilient future food system. The selected documents allowed a mapping of the most important trends: innovations based on metabolic engineering and omics, the use of integrated biorefineries, and digital monitoring platforms are emerging as catalysts for the transition, while high scaling costs, regulatory challenges, and low public acceptance continue to limit large-scale implementation. The analysis highlights both the major advantages (reducing ecological impact, valorizing waste, diversifying food sources) and the current limits of these technologies, proposing a multi-stakeholder roadmap to accelerate the transition to a circular bioeconomy and a low-carbon and climate-resilient food system.

In response to the ongoing challenges associated with natural enzymes, their high production costs, low stability and limited functionality; nanozymes have rapidly emerged as versatile alternative. Such nanocatalysts, based on nanomaterials and nanostructures, offer remarkable tunability of physicochemical properties and excellent durability, and adapt themselves effectively to the requirements of modern biotechnological applications. This review article aims to provide a comprehensive overview of recent advances in the use of naturally occurring iron oxide nanoparticles, produced by magnetotactic bacteria, and to highlight their emerging role as key elements in the development of the new generation of nano-guided biosensors. It provides a comprehensive and systematic analysis of publications in the Web of Science database between 2022 and August 2025, conducted in accordance with PRISMA guidelines. The aim was to assess the current state of the art and identify knowledge gaps in the exploration and application of magnetotactic bacteria as natural and sustainable sources in the design of next-generation biosensors. The natural nanoparticles, formed through biological processes, represent a unique and sustainable alternative to synthetic nanoparticles, offering naturally mimetic enzymatic activity, high biocompatibility, and exceptional stability. This approach opens up revolutionary perspectives in the field of biosensors, proposing a new class of functional materials, iron nanoparticles of biological origin, capable of fundamentally changing the performance, sustainability and reliability of future nanoenzymatic sensing platforms.

Magnetotactic bacteria (MTB), a unique group of Gram-negative prokaryotes, have the remarkable ability to biomineralize magnetic nanoparticles (MNPs) intracellularly, making them promising candidates for various biomedical applications such as biosensors, drug delivery, imaging contrast agents, and cancer-targeted therapies. To fully exploit the potential of MTB, a precise understanding of the structural, surface, and functional properties of these biologically produced nanoparticles is required. Given these concerns, this review provides a focused synthesis of the most widely used microscopic and spectroscopic methods applied in the characterization of MTB and their associated MNPs, covering the latest research from January 2022 to May 2025. Specifically, various optical microscopy techniques (e.g., transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM)) and spectroscopic approaches (e.g., localized surface plasmon resonance (LSPR), surface-enhanced Raman scattering (SERS), and X-ray photoelectron spectroscopy (XPS)) relevant to ultrasensitive MTB biosensor development are herein discussed and compared in term of their advantages and disadvantages. Overall, the novelty of this work lies in its clarity and structure, aiming to consolidate and simplify access to the most current and effective characterization techniques. Furthermore, several gaps in the characterization methods of MTB were identified, and new directions of methods that can be integrated into the study, analysis, and characterization of these bacteria are suggested in exhaustive manner. Finally, to the authors’ knowledge, this is the first comprehensive overview of characterization techniques that could serve as a practical resource for both younger and more experienced researchers seeking to optimize the use of MTB in the development of advanced biosensing systems and other biomedical tools.

Magnetotactic bacteria (MTB) have attracted interest in recent years, mainly due to their natural ability to form intracellular magnetic nanocrystals with potential for biomedical and environmental applications. In this study, we focused on the morphological analysis of the Paramagnetospirillum magnetotacticum MS-1 strain, trying to keep the bacteria as close to their natural state as possible. An important element of this work is the use of untreated bacterial cells, without conductive coating or chemical fixation, using a simple and low-cost support. This choice was made intentionally to avoid changes induced by metallization and to allow direct observation of characteristics that may be relevant in applications where the interaction of the bacteria with the environment plays an important role, such as biosensors. In addition, the analysis was performed on a bacterial suspension stored for approximately 10 months at 4 °C to assess whether the morphology specific to the MS-1 strain is maintained over time. The obtained results show that the general cell morphology and magnetosome organization can be clearly and reproducibly observed even after long-term storage. Without attempting to replace studies based on conventional sample preparation methods, this work provides a complementary perspective and suggests that magnetotactic bacteria may represent a natural and effective alternative to synthetic magnetic nanoparticles, with potential applications in the biomedical and environmental fields.

CD4⁺ T lymphocytes are important regulators of immune homeostasis, and their dysregulation is closely linked to a wide range of diseases. For this reason, their reliable detection remains a major challenge. Despite the fact that current methods are analytically robust, they rely mainly on laboratory infrastructure, limiting their flexibility and wider applicability. The present review analyzes established and emerging approaches for CD4⁺ T-cell detection, with a focus on their practical limitations regarding portability, flexibility and applicability. To the best of our knowledge, for the first time, the authors are examining the possibility of exploring marine magnetotactic bacteria (MTBs) as active biological elements in immune cell detection due to their intrinsic magnetic properties, biological organization, and surface biofunctionalization potential. Rather than offering an immediate technological solution, the use of MTBs serves as a challenging biological framework that could provide more adaptable and sensitive detection strategies. At the same time, the limitations of this concept are acknowledged, emphasizing the need for further experimental validation, considering that this strategy, although promising, remains an exploratory concept.