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Abstract Background The urgent need for affordable and rapid detection methodologies for foodborne pathogens, particularly Escherichia coli (E. coli), highlights the importance of developing efficient and widely accessible diagnostic systems. Dark field microscopy, although effective, requires specific isolation of the target bacteria which can be hindered by the high cost of producing specialized antibodies. Alternatively, M13 bacteriophage, which naturally targets E. coli, offers a cost-efficient option with well-established techniques for its display and modification. Nevertheless, its filamentous structure with a large length-diameter ratio contributes to nonspecific binding and low separation efficiency, posing significant challenges. Consequently, refining M13 phage methodologies and their integration with advanced microscopy techniques stands as a critical pathway to improve detection specificity and efficiency in food safety diagnostics. Methods We employed a dual-plasmid strategy to generate a truncated M13 phage (tM13). This engineered tM13 incorporates two key genetic modifications: a partial mutation at the N-terminus of pIII and biotinylation at the hydrophobic end of pVIII. These alterations enable efficient attachment of tM13 to diverse E. coli strains, facilitating rapid magnetic separation. For detection, we additionally implemented a convolutional neural network (CNN)-based algorithm for precise identification and quantification of bacterial cells using dark field microscopy. Results The results obtained from spike-in and clinical sample analyses demonstrated the accuracy, high sensitivity (with a detection limit of 10 CFU/μL), and time-saving nature (30 min) of our tM13-based immunomagnetic enrichment approach combined with AI-enabled analytics, thereby supporting its potential to facilitate the identification of diverse E. coli strains in complex samples. Conclusion The study established a rapid and accurate detection strategy for E. coli utilizing truncated M13 phages as capture probes, along with a dark field microscopy detection platform that integrates an image processing model and convolutional neural network. Graphical Abstract

Metal‐based nanoparticles (NPs) have entered clinical use for enhancing radiotherapy, but the underlying mechanisms remain ambiguous. Herein, single‐cell analysis of two cell lines in response to megavolt irradiation and a radiomimetic drug, neocarzinostatin (NCS) after coculture with gold NPs with different surface coatings, polyethylene glycol (AuPEG), PEG, and transferrin (AuT) or silica (AuSiO2), is reported. Different surface chemistry presents a major challenge for objective comparison between the biological impacts where major differences in cell‐uptake exist. AuSiO2 NPs are the most efficient for promoting radiosensitization despite being associated with cells 10 times less than the actively targeted AuT NPs. Conversely, for cells exposed to NCS, AuSiO2 NPs impede the radiomimetic action and promote cell survival. AuT NPs enhance death of cells in combination with NCS showing that NPs can sensitize against cytotoxic agents in addition to radiation. While NPs contribute to radiosensitization (or enhancing/impeding chemotherapeutic drug activity), due to cell and cell line heterogeneity, the ultimate radiosensitivity of a cell appears to be dominated by its inherent radiosensitivity and how this cell‐regulated response is manipulated by NPs. This is evidenced through comparison of radiobiological response of cells with equivalent NP association rather than equivalent coculture conditions.

Abstract Blockade of programmed cell death‐1 (PD‐1) is a transformative immunotherapy. However, only a fraction of patients benefit, and there is a critical need for broad‐spectrum checkpoint inhibition approaches that both enhance the recruitment of cytotoxic immune cells in cold tumors and target resistance pathways. Indoleamine 2, 3‐dioxygenase (IDO) small molecule inhibitors are promising but suboptimal tumor bioavailability and dose‐limiting toxicity have limited therapeutic benefits in clinical trials. This study reports on a nanoformulation of the IDO inhibitor navoximod within polymeric nanoparticles prepared using a high‐throughput microfluidic mixing device. Hydrophobic ion pairing addresses the challenging physicochemical properties of navoximod, yielding remarkably high loading (>10%). The nanoformulation efficiently inhibits IDO and, in synergy with PD‐1 antibodies improves the anti‐cancer cytotoxicity of T‐cells, in vitro and in vivo. This study provides new insight into the IDO and PD‐1 inhibitors synergy and validates hydrophobic ion pairing as a simple and clinically scalable formulation approach.