Biology subjects

Lima, L. V.

Publications and source records attributed to Lima, L. V..

4 recordsLinked to original sources

bioRxiv2026

Cell-Dense Bioink Design for Xolography: Coupling Refractive Index-Matching with Increased Photoreactivity

Bioxolography enables high-resolution fabrication of geometrically complex, cell-laden constructs for tissue engineering. However, tissue-relevant cell densities conflict with the optical transparency required for efficient dual-color volumetric printing. In this work, we extend the Bioxolography toolbox to include refractive index (RI) matching for cell-laden bioresins using iodixanol (IDX). Remarkably, IDX enhances optical transparency and boosts reactivity -- a phenomenon unique to Xolography. Yet, excessive IDX compromises dual-color efficiency through increased absorption and undesired UV-only curing, underscoring a central trade-off between optical clarity and photochemical performance. Systematic tuning of resin compositions along an iso-refractive index line demonstrated the versatility of Bioxolography, with IDX enhancing polymerization and 4-Hydroxy-TEMPO providing biocompatible inhibition. Optimizing composition and printing parameters yielded GelMA hydrogels with cell densities up to 5{middle dot}106 cells{middle dot}mL-1. Cell-laden prints achieved sub-100 {micro}m resolution and complex geometries such as channels and gyroids. Using skeletal muscle tissue as a model, we validated RI matched Bioxolography as a promising strategy for tissue engineering by demonstrating cell alignment along printed grooves and formation of mature muscle fibers characterized by MyoHC+ staining and fusion index. By integrating physical, chemical, and biological perspectives, this work advances Xolography toward biomaterials development and reinforces its position as an emerging volumetric (bio)printing technology. Table of Contents O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=175 SRC="FIGDIR/small/729865v1_ufig1.gif" ALT="Figure 1"> View larger version (86K): org.highwire.dtl.DTLVardef@19c0380org.highwire.dtl.DTLVardef@1a9e920org.highwire.dtl.DTLVardef@84210org.highwire.dtl.DTLVardef@294112_HPS_FORMAT_FIGEXP M_FIG C_FIG For printing higher cell density bioresins with Xolography, iodixanol (IDX) is added for refractive index-matching. The addition leads to an unexpected additional effect with increased reactivity in the dual-color photopolymerization. With careful adjustment of the resin composition and the printing parameters, Bioxolography is proven as a viable tool for tissue engineering.

bioengineering↗

bioRxiv2025

Paradoxical Phenotype of Fibromyalgia Neutrophils with Elevated Baseline Inflammation but Blunted Response to Stimulation

Fibromyalgia (FM) is a severe pain condition of unknown etiology. Here, we performed transcriptomics analyses of peripheral neutrophils exposed to an inflammatory stimulus, comparing responses of neutrophils obtained from FM patients versus healthy controls. We observed a state of inflammation in neutrophils from FM patients. However, FM neutrophils were unable to efficiently respond to lipopolysaccharide (LPS). This impairment was especially characteristic of FM patients with no improvement after 5 years after diagnosis in comparison with those who did improve. Blood plasma from FM patients directly stimulated a wide range of primary sensory neurons in vitro and induced pain hypersensitivity when injected into mice. Further analysis identified NF-{kappa}B suppression as a key biological process associated with low-grade inflammation and LPS non-responsiveness in neutrophils from FM patients. The clinically used NF-{kappa}B activator, bryostatin, alleviated hypersensitivity in mice treated with FM plasma, pointing to controlled inflammation induction through reactivation of the NF-{kappa}B pathway as a possible therapeutic target for FM treatment. Our whole blood single-cell RNA sequencing replicated this NF-{kappa}B-driven inflammation observed in bulk analyses transcriptomics in FM patients and revealed that this inflammatory signature is strongly pronounced not only in neutrophils, but across a broad range of immune cells.

molecular biology↗

bioRxiv2022

Development and validation of PainFace, a software platform that simplifies and standardizes mouse grimace analyses

Facial grimaces are now commonly used to quantify spontaneous pain in mice and other mammalian species, but scoring remains subjective and relies on humans with very different levels of proficiency. Here, we developed a Mouse Grimace Scale (MGS) for black-coated (C57BL/6) mice consisting of four facial action units (orbitals, nose, ears, whiskers). We used this scale to generate ground truth data from over 70,000 images of black mice in different settings. With this large data set, we developed a deep neural network and cloud-based software platform called PainFace (http://painface.net) that accurately scores facial grimaces of black mice on a 0-8 scale. PainFace generates over two orders of magnitude more MGS data than humans can realistically achieve, and at superhuman speed. By analyzing the frequency distribution of grimace scores, we found that mice spent >7x more time in a high grimace state following laparotomy surgery relative to sham surgery controls. The analgesic carprofen reduced the amount of time animals spent in this high grimace state after surgery. Specific facial action unit score combinations were overrepresented following laparotomy surgery, suggesting that characteristic facial expressions are associated with a high grimace state. We performed validation experiments in two labs located in different countries to demonstrate reproducibility of the PainFace platform. To further enhance rigor and reproducibility, we will invite pain researchers to beta test PainFace and then incorporate their feedback into the software and manuscript prior to peer review. While this study is focused on mice, PainFace was designed to simplify, standardize, and scale up grimace analyses with many other mammalian species, including humans.

neuroscience↗

bioRxiv2021

FRAGMENTED BIODIVERSITY: FERNS AND LYCOPHYTES FROM FOREST FRAGMENTS IN JUIZ DE FORA, MINAS GERAIS, BRAZIL

The Atlantic Forest is one of the most threatened formations in the world. In this context, the urbanization process stands out as one of the major factors causing environmental degradation, mainly due to the loss of native vegetation and habitat destruction. In order to fill this gap, we carried out the inventory of ferns and lycophytes in the forest remnants of the municipality of Juiz de Fora. We analyzed more than 1,353 samplings recorded throughout approximately 150 years, as result we recorded a total of 174 species distributed in 73 genera and 26 families. The most representative families were Pteridaceae with 32 species, followed by Polypodiaceae with 26 and Thelypteridaceae with 20. In addition, we present the historical data on the sampling of ferns and lycophytes, as well as the history of the fragmentation process of the Atlantic Forest remnants in the municipality. Juiz de Fora becomes an interesting model for broader floristic studies, generating subsequent subsidies for conservation actions and preservation of the natural patrimony.

plant biology↗