Low-Friction Soft Robots for Targeted Bacterial Infection Treatment in Gastrointestinal Tract

Deciphering the molecular interaction between Vitamin D3 and pepsin by in vitro and in silico perspectives

The current study explored the molecular interaction between Vitamin D3 (Vit D3) and pepsin using multi-spectroscopic, molecular dynamic simulation (MDS), and molecular docking. The fluorescence emission spectra discovered Vit D3 interacted with pepsin in a static quenching manner due to the formation of the steady-state complex. Thermodynamic data revealed the spontaneous binding of Vit D3 on pepsin. The formation of the Pepsin-Vit D3 complex was also validated by circular dichroism (CD) spectroscopy. The fluorescence and CD spectroscopy results revealed Vit D3 altered the tertiary and secondary structure of pepsin, respectively. Meanwhile, FTIR spectroscopy results revealed a hypochromic shift in the amide I and II peaks. Kinetic parameters showed Vit D3 inhibited the activity of pepsin by the uncompetitive process. Applied spectroscopic methods disclosed that Vit D3 binding to pepsin caused microenvironmental modifications around the aromatic residues of protein and changed its structure and function. Moreover, MD simulation and molecular docking were done to analyze the formation of Pepsin-Vit D3 complexes. Molecular docking findings demonstrated the interaction of Vit D3 with pepsin mainly involved van der Waals forces and hydrogen bonds that were in good agreement with the fluorescence results. Finally, MDS findings including RMSD, RMSF, and RG confirmed all the experimental data.

Green Synthesis of Cymodocea serrulata Zinc Oxide Nanoparticles for Sustainable Antibacterial, and Mosquito Control and their Toxicity to non-target Organisms

Mosquito-borne diseases such as dengue, malaria, and filariasis have become serious global health concerns due to their contagious nature and widespread prevalence. In this study, ZnO NPs biosynthesized using the seagrass extract of Cymodocea serrulata (CS-ZnO NPs) were prepared from the leaf part and evaluated for their toxicity potential against the larvae, pupae, and adults of various mosquito species, including Aedes aegypti, Culex quinquefasciatus, and Anopheles stephensi. The CS-ZnO NPs were characterized using UV-Vis spectroscopy, XRD, FTIR, FE-SEM, EDX, and zeta potential analyses. The CS-ZnO NPs demonstrated significant antibacterial activity against tested bacterial strains: Pseudomonas otitidis (22 ± 0.81 mm), Enterococcus faecalis (18.66 ± 0.47 mm), Bacillus subtilis (14 ± 0.81 mm), and Serratia marcescens (9.66 ± 0.47 mm). Among the mosquito species tested, A. stephensi exhibited the most effective toxicity response. The ovicidal activity of CS-ZnO NPs against A. stephensi showed 12% egg hatchability at a concentration of 100 µg/mL. Furthermore, the larvicidal efficacy of CS-ZnO NPs against A. stephensi displayed strong lethal effects, with LC50 and LC90 values (in µg/mL) recorded as follows: 2.79 and 72.86 for the first instar, 5.89 and 209.93 for the second instar, 7.38 and 328.43 for the third instar, 9.56 and 435.36 for the fourth instar larvae; 8.18 and 357.68 for pupae; and 4.51 and 238.96 for adults. Biosafety assessments were conducted on Danio rerio embryos and Artemia salina nauplii to confirm the non-toxic nature of CS-ZnO NPs. Overall, C. serrulata-synthesized CS-ZnO NPs present a promising, eco-friendly alternative for controlling mosquitoes and eradicating deadly mosquito-borne diseases such as filariasis, dengue, and malaria.

The gastrointestinal mycobiome in inflammation and cancer: unraveling fungal dysbiosis, pathogenesis, and therapeutic potential

The gastrointestinal mycobiome, comprising diverse fungal species, plays a significant role in gastrointestinal carcinogenesis and inflammatory bowel disease (IBD) pathogenesis. Recent studies have demonstrated that dysbiosis of the gut mycobiome, characterized by an overrepresentation of pathogenic fungi such as Candida albicans and Aspergillus, correlates with increased inflammation and cancer risk. For instance, C. albicans has been shown to induce colonic inflammation through the activation of pattern recognition receptors and the release of pro-inflammatory cytokines, exacerbating IBD symptoms and potentially facilitating tumorigenesis. Additionally, metagenomic analyses have revealed distinct fungal signatures in colorectal cancer tissues compared to adjacent healthy tissues, highlighting the potential of fungi as biomarkers for disease progression. Mechanistically, gut fungi contribute to disease through biofilm formation, mycotoxin secretion (e.g., aflatoxins, candidalysin), pro-inflammatory cytokine induction (e.g., IL-1β, IL-17), and disruption of epithelial barriers-creating a tumor-promoting and inflammation-prone environment. Furthermore, the interplay between fungi and the bacterial microbiome can amplify inflammatory responses, contributing to chronic inflammation and cancer development. Fungal interactions with bacterial communities also play a synergistic role in shaping mucosal immune responses and enhancing disease severity in both cancer and IBD contexts. As research continues to elucidate these complex fungal-host and fungal-bacterial interactions, targeting the gut mycobiome may offer novel therapeutic avenues for managing IBD and gastrointestinal cancers, emphasizing the need for integrated, mechanistically informed approaches to microbiome research.

Robotic Ultrasound Scanning End-Effector with Adjustable Constant Contact Force

In modern medical treatment, ultrasound scanning provides a radiation-free medical imaging method for the diagnosis of soft tissues via skin contact. However, the exerted contact force heavily relies on the skill and experience of the operator, which poses great inspection instability. This article reports on a robotic ultrasound scanning system with a constant-force end-effector. Its uniqueness is the introduction of a hybrid active-passive force control approach to maintaining a constant contact force between the ultrasound probe and the continually changing surface. In particular, the passive constant-force mechanism provides strong buffering to the force variation. The active force control system improves flexibility and provides long-stroke positioning. Experimental tests on both silicone models and human volunteers demonstrate the capability of the proposed robotic ultrasound scanning system for obtaining qualified ultrasound images with high repeatability. Moreover, the ease of operation of the robotic US scanning system is verified. This work provides a promising method to assist doctors in conducting better and cushier ultrasound scanning imaging.

Use of pH-sensitive microcapsules for selective delivery of nanozymes and biological enzymes in small intestine

Unlike the intravenous route, oral delivery systems face challenges due to an acidic gastric environment, which can degrade or inactivate therapeutic compounds before they reach the small intestine (SI). Therefore, developing oral delivery strategies that protect cargo from acidic environments and release the content in the SI is imperative. Herein, a novel approach utilizes the pH-sensitivity of alginate-based microcapsules that degrade and release the contents at pH ≥ 7.0. The microcapsules were used to encapsulate gold nanoparticles (AuNPs, a model nanozyme) of varying sizes (2, 15, and 70 nm) and horseradish peroxidase (HRP, a model enzyme). The AuNPs- and HRP-loaded microcapsules (AuNPs-MCap and HRP-PEG MCap) were unaffected at acidic pH (2.0-6.0), as the intrinsic structure and properties of encapsulated AuNPs and HRP were intact. The microcapsules rapidly released the encapsulated AuNPs and HRP at pH ≥ 7.0. In vivo, oral administration of AuNPs-MCap and HRP-PEG MCap to Wistar rats also showed significantly enhanced absorption of AuNPs and HRP in SI, leading to higher concentrations in blood than in their corresponding unencapsulated forms. Overall, the results underscore the potential of pH-responsive microcapsules for protecting pH-sensitive nanozymes, biological enzymes and other bioactive compounds from the acidic gastric environment and for effective and targeted delivery to the SI.

Exploring the potential of bacterial-derived EVs for targeted enzyme replacement therapy: mechanisms, applications, and future directions

Extracellular vesicles (EVs) are membrane-bound vesicles produced by cells which promote intercellular communication by delivering different contents such as DNA, RNA, and proteins. These vesicles, nano-sized and released into the extracellular space, are present everywhere under both normal and pathological conditions. Probiotic-derived EVs can serve as nanocarriers for therapeutic cargo, particularly in enzyme replacement therapy (ERT). Traditional ERT for lysosomal storage diseases (LSDs) faces significant challenges, including the inability of enzymes to cross the blood-brain barrier (BBB) and their susceptibility to degradation. Studies show EVs can transport enzyme cargoes across the BBB, accurately delivering them to tissues affected by LSDs. Probiotic EVs also possess immunomodulatory properties, providing therapeutic benefits in inflammatory conditions. However, their potential for delivering deficient enzymes in LSDs remains unclear. This review discusses using probiotic EVs in ERT for targeted enzyme delivery to treat LSDs more efficiently than other exosomes. This novel strategy minimizes off-target delivery and enhances immunomodulatory effects, making it more advantageous than live probiotic bacteria. Probiotic EVs show promise for therapeutic approaches, especially in treating LSDs and inflammatory diseases, by modulating immune responses and delivering enzymes across biological barriers like the BBB. Future research should optimize production, engineer targeted therapies, and confirm safety and efficacy through clinical trials. Expanding studies to include diverse probiotic strains could uncover new therapeutic applications, enhancing their versatility and effectiveness.

Antibacterial Activity of Ciprofloxacin-Based Carbon Dot@Silver Nanoparticle Composites

The combined green synthesis of carbon dots (CDs) from the hydrothermal conversion of ciprofloxacin and silver nanoparticles (AgNPs) using sodium alginate as a reducing and stabilizing agent results in arrangements of nanostructures (CD@AgNP composites) with positive surface charge that electrostatically interact with Gram-positive and Gram-negative bacteria in the planktonic form and also biofilm forms, inhibiting their growth and adhesion on surfaces. Outstanding performance for CD-based materials results in a 5-log reduction in colony-forming units (CFU/mL) of E. coli after 1 h of treatment and a decrease of 99.32% in the consolidated biofilm of S. aureus. These nanostructures result in the intrinsic fluorescence of CDs and an overall eco-friendly preparation process that can be explored in disinfection procedures based on the direct administration of a sanitizer based on nanoparticles dispersed in an aqueous solution. This process is justified by the adequate conversion of antibiotics in positively charged CDs and composites with AgNPs, resulting in nanocomposites in which the prevailing cationic effect facilitates their incorporation and diffusion into bacterial membrane cells.

Polymer-Mediated Delivery of Amphotericin B for Fungal Infections

Invasive fungal infections have been an increasingly global issue with high mortality. Amphotericin B (AmB), as the "gold standard" antifungal drug, has broad-spectrum antifungal activity and low clinical resistance. Therefore, AmB is the most commonly used polyene antibiotic for the treatment of invasive fungal infections. However, the serious side effects as well as the low bioavailability of AmB strongly restrict its clinical applications. Polymer, with its diversified molecular design, is widely used in drug delivery in the form of polymeric prodrugs, nanoparticles, hydrogels, etc. Therefore, polymers hold great promise for the delivery of AmB in treating fungal infections. This review summarizes recent advances in polymer-based delivery systems of AmB for the treatment of fungal infections, including polymer-AmB conjugates, nanotechnology-based polymeric delivery systems, hydrogels, and polymeric microneedles. Taking advantage of polymer-based delivery strategies, special attention is paid to reducing the side effects and improving the bioavailability of AmB for safe and effective antifungal therapy. Finally, the limitations and possible future directions of polymer-based AmB delivery systems are discussed.

Encoder-Decoder Variant Analysis for Semantic Segmentation of Gastrointestinal Tract Using UW-Madison Dataset

The gastrointestinal (GI) tract, an integral part of the digestive system, absorbs nutrients from ingested food, starting from the mouth to the anus. GI tract cancer significantly impacts global health, necessitating precise treatment methods. Radiation oncologists use X-ray beams to target tumors while avoiding the stomach and intestines, making the accurate segmentation of these organs crucial. This research explores various combinations of encoders and decoders to segment the small bowel, large bowel, and stomach in MRI images, using the UW-Madison GI tract dataset consisting of 38,496 scans. Encoders tested include ResNet50, EfficientNetB1, MobileNetV2, ResNext50, and Timm_Gernet_S, paired with decoders UNet, FPN, PSPNet, PAN, and DeepLab V3+. The study identifies ResNet50 with DeepLab V3+ as the most effective combination, assessed using the Dice coefficient, Jaccard index, and model loss. The proposed model, a combination of DeepLab V3+ and ResNet 50, obtained a Dice value of 0.9082, an IoU value of 0.8796, and a model loss of 0.117. The findings demonstrate the method's potential to improve radiation therapy for GI cancer, aiding radiation oncologists in accurately targeting tumors while avoiding healthy organs. The results of this study will assist healthcare professionals involved in biomedical image analysis.

Precision therapeutics for inflammatory bowel disease: advancing ROS-responsive nanoparticles for targeted and multifunctional drug delivery

Inflammatory bowel disease (IBD) is a severe chronic intestinal disorder with a rising global incidence. Current therapies, including the delivery of anti-inflammatory drugs and probiotics, face significant challenges in terms of safety, stability, and efficacy. In IBD patients, the activity of antioxidant enzymes (e.g., superoxide dismutase, glutathione peroxidase, and glutathione reductase) is reduced at the site of intestinal inflammation, leading to the accumulation of reactive oxygen species (ROS). This accumulation damages the intestinal mucosa, disrupts tight junctions between cells, and compromises the integrity of the intestinal barrier, exacerbating IBD symptoms. Therefore, nanoparticles responsive to ROS and capable of mimicking antioxidant enzyme activity, such as boronates, polydopamine, sulfides, and metal nanozymes, have emerged as promising tools. These nanoparticles can respond to elevated ROS levels in inflamed intestinal regions and release drugs to effectively neutralize ROS, making them ideal candidates for IBD treatment. This review discusses the application of various ROS-responsive nanomaterial delivery systems in IBD therapy, highlights current challenges, and outlines future research directions. Furthermore, we explore the "layered programmable delivery" strategy, which combines ROS-responsive nanoparticles with pH-responsive and cell membrane-targeted nanoparticles. This strategy has the potential to overcome the limitations of single-mechanism targeted drug delivery, enabling multi-range and multi-functional treatment approaches that significantly enhance delivery efficiency, providing new insights for the future of localized IBD treatment.

From Cure to Crisis: Understanding the Evolution of Antibiotic-Resistant Bacteria in Human Microbiota

The growing prevalence of antibiotic-resistant bacteria within the human microbiome has become a pressing global health crisis. While antibiotics have revolutionized medicine by significantly reducing mortality and enabling advanced medical interventions, their misuse and overuse have led to the emergence of resistant bacterial strains. Key resistance mechanisms include genetic mutations, horizontal gene transfer, and biofilm formation, with the human microbiota acting as a reservoir for antibiotic resistance genes (ARGs). Industrialization and environmental factors have exacerbated this issue, contributing to a rise in infections with multidrug-resistant (MDR) bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA) and carbapenem-resistant Enterobacteriaceae. These resistant pathogens compromise the effectiveness of essential treatments like surgical prophylaxis and chemotherapy, increase healthcare costs, and prolong hospital stays. This crisis highlights the need for a global One-Health approach, particularly in regions with weak regulatory frameworks. Innovative strategies, including next-generation sequencing (NGS) technologies, offer promising avenues for mitigating resistance. Addressing this challenge requires coordinated efforts, encompassing research, policymaking, public education, and antibiotic stewardship, to safeguard current antibiotics and foster the development of new therapeutic solutions. An integrated, multidimensional strategy is essential to tackle this escalating problem and ensure the sustainability of effective antimicrobial treatments.