Biology subjects

Boitet, M.

Publications and source records attributed to Boitet, M..

4 recordsLinked to original sources

bioRxiv2026

3D Printed Customizable Radiopaque Markers for Assessing Gastrointestinal Transit

Tracking gastrointestinal (GI) transit in preclinical models is essential for assessing gut motility and drug delivery. Current preclinical methods rely on end-to-end transit measurements or emptying studies that require terminal endpoints and organ explanation. Clinically, radiopaque "Sitz" markers are administered orally and their position in the GI tract is assessed through radiography. Sitz markers have been in use since 1969 and are typically mass-produced using industrial molding or extrusion, resulting in a single, fixed geometry with limited tunability. We present a stereolithography (SLA)-based method to fabricate customizable radiopaque markers using additive manufacturing with a barium sulfate (BaSO4)-doped resin. We demonstrate precise control over marker geometry, a key advantage over existing markers. Furthermore, we apply this method in vivo, tracking markers in a live rat model from ingestion to excretion using serial CT imaging. We systematically investigate how changes in marker geometry impact GI residency and transit time. Our results show that 3D printed markers provide a flexible and tunable platform for radiopaque marker fabrication and enable investigation of the fundamental relationship between a markers physical properties and its performance in a dynamic biological environment. This work establishes a novel, tunable platform for GI motility evaluation and drug delivery studies.

bioengineering↗

bioRxiv2025

Nuclear Myosin 1 links genomic architecture to adipose tissue remodeling, metabolic inflammation and obesity in mice

During adipogenesis, a metabolic shift from oxidative phosphorylation (OXPHOS) to aerobic glycolysis enables preadipocytes to meet the biosynthetic and energetic demands of differentiation. Nuclear myosin 1 (NM1), a chromatin-associated actomyosin motor that regulates transcription and chromatin accessibility, is essential for maintaining OXPHOS. Here, we identify NM1 as a key regulator of adipocyte differentiation and adipose tissue homeostasis. Integration of ATAC-seq and RNA-seq in NM1-deficient mouse embryonic fibroblasts revealed coordinated dysregulation of adipogenic genes (Insig1, Lipg, Fat1) and altered enhancer accessibility near Klf6, Foxo3, Smad5, and Gata4. NM1 knockout mesenchymal stem cells showed impaired adipogenic differentiation despite adipocyte hypertrophy. In vivo, NM1-deficient mice developed age-dependent visceral obesity with transcriptional reprogramming in white adipose tissue (WAT), including downregulation of adipogenesis and mitochondrial pathways, and activation of IFNG-, IL33-, and TNF-driven inflammation. Cross-species analysis revealed overlap with MYO1C-centered regulatory modules in human adipose tissue, implicating NM1/MYO1C in conserved chromatin-based control of adipose biology

cell biology↗

bioRxiv2025

pH-Responsive Near Infrared Light Triggered Hydroxyapatite Nanoparticles for Targeted Photothermal Cancer Therapy

Photothermal therapy (PTT), which utilizes photothermal agents (PTAs) to induce localized hyperthermia within tumors upon light irradiation, has emerged as a promising cancer treatment strategy. However, low water solubility, poor in vivo circulation stability and a lack of tumor specificity of many common PTAs limit their applicability. To address these issues, we have developed a simple, yet highly potent, tumor-targeted nanotheranostic system that consists of lipid/PEG-coated hydroxyapatite nanoparticles (LHAPNs) encapsulating the near-infrared (NIR) photothermal dye IR106 (LHAPNIRs). The lipid coat serves to retain the encapsulated dye and prevent serum protein adsorption and macrophage recognition, which would otherwise destabilize the nanoparticles and hinder their tumor targeting efficiency. Additionally, the coat is functionalized with the tumor-acidity-triggered rational membrane (ATRAM) peptide for efficient and specific internalization into tumor cells in the mildly acidic microenvironment of tumors. The nanoparticles facilitated real-time fluorescence and thermal imaging of tumors and demonstrated potent NIR-light triggered anticancer activity in vitro and in vivo, without adversely affecting healthy tissue, leading to markedly prolonged survival. Our results demonstrate that the biocompatible and biodegradable ATRAM-functionalized LHAPNIRs (ALHAPNIRs) effectively combine dual-mode diagnostic imaging with targeted cancer PTT.

bioengineering↗

bioRxiv2024

Wirelessly-Powered Ingestible Electronic Capsule for Non-invasive Gastrointestinal Optogenetics

Optogenetics enables the activation and inhibition of neurons with cell specificity. The gut harbors intricate networks of enteric and central neurons. Uncovering these neuronal pathways in vivo is challenging with traditional neuroscience probes due to the highly motile and harsh gut environment. Here we report the development of an ingestible electronic capsule for non-invasive optical gut stimulation (ICOPS) in rodents. ICOPS is powered wirelessly via a transmitter coil, dosed via oral gavage, and safely excreted without causing obstruction. ICOPS permits modular interchangeability of onboard light-emitting diodes (LEDs) for illumination. We exemplify this with optical irradiance at 470 nm, a commonly-used wavelength in optogenetics for activating channelrhodopsin2. ICOPS features a micro-LED ({micro}LED), a 460-turn coil wound around a ferrite core, and a resonating capacitor. We optimized the transmitting and receiving circuits to achieve maximum power transfer at low operating frequencies (45-140 kHz), overcoming challenges like loose coupling and misalignment. The capsule operates effectively at a distance up to 12 cm longitudinally, 9 cm laterally, and 75{degrees} rotational angle relative to the magnetic field. Specific absorption rate (SAR) calculations indicate transmitter-induced SAR levels within safe limits for the occupational environment at 6 Arms and 45 and 63 kHz frequencies ICOPS is robust and transits through the rat gastrointestinal (GI) tract in under 20 hours intact. We demonstrate in vivo functionality and viability of ICOPS using IVIS micro-computed tomography ({micro}CT). ICOPS could pave the way for non-invasive optogenetic interfacing of enteric neural circuits towards their use to regulate motility, visceral pain, and other gastrointestinal disorders.

bioengineering↗