Publicaciones

@article{nokey,

title = {Impact of Vascular Density on Pancreatic Islet Viability: A Computational Study},

author = {Gerardo J Félix-Martínez and Lizbeth de la Cruz and Daniel Whisman and J. Rafael Godínez-Fernández},

url = {https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2025.1707026/abstract},

doi = {10.3389/fphys.2025.1707026},

year  = {2025},

date = {2025-11-07},

journal = {Frontiers in Physiology},

abstract = {Pancreatic islets are densely vascularized clusters of cells that secrete insulin, glucagon, and somatostatin, hormones essential to glucose metabolism. The viability and function of islet cells rely on the availability of oxygen and nutrients supplied by islet capillaries. In this work, we developed a computational model of vascularized pancreatic islets, aiming to estimate the proper level of vascularization to ensure cell viability. The simulated islets were reconstructed from experimental data of human and mouse, with capillaries generated using a pathfinding algorithm. The number of capillaries required to maintain islet cell viability was determined by analyzing oxygen gradients resulting from cell consumption at 6-and 20-mM glucose concentrations and a varying number of capillaries. Our simulations in human and mouse models suggest that >100 capillaries (i.e. vascular density >5.9%) are required to maintain >96% of cells in a viable state at 6-and 20-mM glucose. From this percentage of viable cells, >75% of cells are in functional state (PO₂ > 10 mmHg) at 6 mM glucose while it reduces to ~50% at 20 mM glucose. These models represent an advancement in computational models available to study islet physiology by incorporating the vascular system to enable more accurate, predictive, and physiologically relevant simulations in health, disease, and bioengineering approaches where changes in the islet vasculature are relevant. To support the broad application of the model, we provide a user-friendly computational tool where the viability of islet cells can be estimated based on a given number of capillaries, islet size and glucose level.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Cholesterol Concentration in Cell Membranes and its Impact on Receptor–Ligand Interaction: A Computational Study of ATP-Sensitive Potassium Channels and ATP Binding},

author = {César Millán and Iris Serratos and Gerardo J. Félix-Martínez and Gerardo Blancas and J. Rafael Godínez-Fernández},

url = {https://link.springer.com/article/10.1007/s00232-025-00345-4},

doi = {10.1007/s00232-025-00345-4},

year  = {2025},

date = {2025-03-26},

journal = {The Journal of Membrane Biology},

pages = {1-12},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {El potencial de la Espectroscopía Raman en la caracterización de fibras electrohiladas compuestas },

author = {Uribe Juárez Omar Eduardo and Morales Corona Juan and Vivar Velázquez Flor Ivon and Olayo González Roberto and Godínez Fernández José Rafael},

url = {https://contactos.izt.uam.mx/index.php/contactos/article/view/475},

year  = {2024},

date = {2024-12-19},

urldate = {2024-12-19},

journal = {Contactos, Revista de Educación en Ciencias e Ingeniería},

volume = {139},

abstract = {En este trabajo se muestra la espectroscopía Raman como técnica para la caracterización de fibras electrohiladas hechas de ácido poliláctico (PLA) y ácido poliláctico/ hidroxiapatita (HA), relacionando los modos vibracionales de la PLA y la HA con los principales picos registrados en sus espectros Raman, utilizando sus picos característicos para determinar la distribución del PLA y la HA en las fibras de PLA/HA, por último, se presenta una herramienta (WebMo) para la simulación de espectros Raman de moléculas pequeñas, como el ácido láctico y el fosfato.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Impact of oxygen and glucose availability on the viability and connectivity of islet cells: A computational study of reconstructed avascular human islets},

author = {Gerardo J. Félix-Martínez and Diana María Osorio-Londoño and J. Rafael Godínez-Fernández},

url = {https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1012357},

doi = {10.1371/journal.pcbi.1012357},

issn = {1553-7358},

year  = {2024},

date = {2024-08-08},

urldate = {2024-08-08},

journal = {PLOS Computational Biology},

volume = {20},

issue = {8},

pages = {e1012357},

abstract = {The experimental study and transplantation of pancreatic islets requires their isolation from the surrounding tissue, and therefore, from the vasculature. Under these conditions, avascular islets rely on the diffusion of peripheral oxygen and nutrients to comply with the requirements of islet cells while responding to changes in body glucose. As a complement to the experimental work, computational models have been widely used to estimate how avascular islets would be affected by the hypoxic conditions found both in culture and transplant sites. However, previous models have been based on simplified representations of pancreatic islets which has limited the reach of the simulations performed. Aiming to contribute with a more realistic model of avascular human islets, in this work we used architectures of human islets reconstructed from experimental data to simulate the availability of oxygen for α, β and δ-cells, emulating culture and transplant conditions at different glucose concentrations. The modeling approach proposed allowed us to quantitatively estimate how the loss of cells due to severe hypoxia would impact interactions between islet cells, ultimately segregating the islet into disconnected subnetworks. According to the simulations performed, islet encapsulation, by reducing the oxygen available within the islets, could severely compromise cell viability. Moreover, our model suggests that even without encapsulation, only microislets composed of less than 100 cells would remain viable in oxygenation conditions found in transplant sites. Overall, in this article we delineate a novel modeling methodology to simulate detailed avascular islets in experimental and transplant conditions with potential applications in the field of islet encapsulation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Interactions of Cardiac Proteins with Plasma-Synthesized Polypyrrole (PSPy) to Improve Adult Cardiomyocytes Culture },

author = {Gómez-Quintero Teresa and Olayo Roberto and Morales Corona Juan and Uribe Juárez Omar and Millán Pacheco César and Godínez Fernández J. Rafael and Serratos Iris },

url = {https://www.mdpi.com/2073-4360/16/11/1470},

doi = {10.3390/polym16111470 },

year  = {2024},

date = {2024-05-22},

urldate = {2024-05-22},

journal = {Polymers},

volume = {16},

issue = {11},

abstract = {Plasma-Synthesized Polypyrrole (PSPy) has been reported as a biomaterial suitable for cell growth in vitro and in vivo. An experimental duplicate was carried out that showed the growth of cardiomyocytes with PSPy, following a protocol previously reported by the working group. The cardiomyocytes cultured with the biomaterial retained their native morphological characteristics, a fundamental key to improving cardiac cell therapy procedures. Such observations motivated us to investigate the molecular characteristics of the biomaterial and the type of interactions that could be occurring (mainly electrostatic, hydrogen bonds, and non-polar). Additionally, PSPy has been studied to establish the probable mechanisms of action of the biomaterial, in particular, its action on a group of cell membrane proteins, integrins, which we know participate in the adhesion of cells to the extracellular matrix, in adhesion between cells and as bidirectional signal transducer mechanisms. In this work, we carried out studies of the interactions established between cardiac integrins α2β1 and α5β1 with different PSPy models by molecular docking studies and binding free energies (ΔGb) calculations. The models based on a previously reported PSPy molecule have three variable terminal chemical groups, with the purpose of exploring the differences in the type of interaction that will be established by modifying the position of an amino (-NH2), a hydroxyl (-OH), and a nitrile (C≡N) in (fixed) groups, as well as the length of the terminal chains (a long/short -NH2). A model with short chains for the -OH and -NH2 (lateral) group was the model with the best interactions with cardiac integrins. We experimentally verified the direct interaction of cardiomyocytes with the PSPy biomaterial observed in rat primary cultures, allowing us to validate the favorable interactions predicted by the computational analysis.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Short and long-range correlations in single-channel currents from inwardly rectifying K channels},

author = {Gerardo J. Félix-Martínez and Arturo Picones and J. Rafael Godínez-Fernández},

url = {https://www.sciencedirect.com/science/article/abs/pii/S0960077923012353},

doi = {10.1016/j.chaos.2023.114333},

issn = { 1873-2887},

year  = {2023},

date = {2023-12-15},

urldate = {2023-12-15},

journal = {Chaos, Solitons & Fractals },

volume = {178},

pages = {114333},

abstract = {Ion channels mediate the transport of ions through the cell membrane and are involved in key processes such as muscle contraction, nerve excitability and hormone secretion. For decades, the main focus of the standard techniques for the analysis and modeling of single-channel currents has been to characterize the gating of ionic channels by analyzing the current amplitudes and dwell-time histograms, thus neglecting the possibility that pore fluctuations (open and closed), usually considered to be stochastic noise, might contain valuable information about the functional aspects of ion channels. Based on the analysis of a deterministic model indicating that the stochastic gating of ion channels could be produced by correlated pore fluctuations, in this work, we analyzed experimental recordings of single channel currents of an inwardly rectifying K channel in order to demonstrate the presence of both short and long range correlations in the open and closed pore fluctuations},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Área de investigación en Ingeniería Biomédica: Historia de nuestros laboratorios de investigación},

author = {Aída Jiménez González and Juan Manuel Cornejo Cruz and José Rafael Godínez Fernández and Jesús Alfonso Martínez Ortiz and Enrique Luis Hernández Matos and Norma Castañeda Villa and Pilar Granados Trejo},

url = {https://contactos.izt.uam.mx/index.php/contactos/article/view/256},

year  = {2023},

date = {2023-10-01},

urldate = {2023-10-01},

journal = {Contactos, Revista de Educación en Ciencias e Ingeniería,},

volume = {127},

abstract = {The aim of this work was to gather information about the story of the four research laboratories in the Area of Biomedical Engineering, Department of Electrical Engineering, Division of Basic Science and Engineering, at Universidad Autónoma Metropolitana-Iztapalapa. To this end, a senior member of each laboratory was invited to write the narrative corresponding to the Laboratory of Audiology, the Laboratory of Biophysics and Tissue Engineering, the Laboratory of Engineering of Physiological Phenomena, and the Laboratory of Medical Instrumentation. As a result, this document conveys information about the origins, profiles, members, current projects, partners, partnerships and social impact},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {A primer on modelling pancreatic islets: from models of coupled β-cells to multicellular islet models},

author = {Gerardo J. Félix-Martínez and J. Rafael Godínez-Fernández},

url = {https://www.tandfonline.com/doi/full/10.1080/19382014.2023.2231609?src=},

doi = {10.1080/19382014.2023.2231609},

issn = {1938-2022},

year  = {2023},

date = {2023-07-07},

urldate = {2023-07-07},

journal = {Islets},

volume = {15},

issue = {1},

abstract = {Pancreatic islets are mini-organs composed of hundreds or thousands of ɑ, β and δ-cells, which, respectively, secrete glucagon, insulin and somatostatin, key hormones for the regulation of blood glucose. In pancreatic islets, hormone secretion is tightly regulated by both internal and external mechanisms, including electrical communication and paracrine signaling between islet cells. Given its complexity, the experimental study of pancreatic islets has been complemented with computational modeling as a tool to gain a better understanding about how all the mechanisms involved at different levels of organization interact. In this review, we describe how multicellular models of pancreatic cells have evolved from the early models of electrically coupled β-cells to models in which experimentally derived architectures and both electrical and paracrine signals have been considered.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}