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Ramella-Roman, J.

Publications and source records attributed to Ramella-Roman, J..

3 recordsLinked to original sources

Advanced Optical Microscopy Reveals Spatio-Temporal Dynamics of Cervix Remodeling during Gestation

Collagen remodeling in the uterine cervix is a vital process in pregnancy that allows for timely fetal delivery, yet its spatio-temporal details are still not fully understood. In this study, we measured collagen reorganization at different stages of murine gestation and at various cervical depths. We used polarization-resolved Second Harmonic Generation microscopy to specifically detect fibrillar collagen and assess its orientation with sub-micrometer resolution. We imaged large cervical areas using automated mosaicking and implemented an analysis pipeline that showed significant region-dependent changes in collagen quantity, porosity, and orientation disorder. Notably, we found that collagen disorganization begins in the lower cervix at gestation day 12 and extends throughout the entire cervix by day 15. Additionally, we demonstrated that the temporal dynamics of disorganization, without spatial sensitivity, can also be tracked using Mueller Matrix imaging, which is a clinically deployable method. These findings should improve understanding and diagnosis of gestation-related issues such as premature birth.

biophysics↗

Gold Nanocages as Scattering Contrast Agents for Optical Coherence Tomography

We report a scattering-dominant agent that significantly enhances optical coherence tomography (OCT) imaging contrast. The agent is based on gold nanocages, which exhibit a surface plasmon resonance (SPR) peak around 780 nm and a scattering cross-section that exceeds the absorption cross-section. The synthesis protocol for these nanocages is provided in detail. The optical properties of the gold nanocages were characterized using OCT imaging and further validated with integrating sphere measurements. OCT contrast enhancement was demonstrated through imaging of tissue phantoms containing embedded nanocages, as well as ex vivo imaging of mouse tissues and in vivo imaging of a mouse tumor following intravenous administration of PEGylated gold nanocages. To the best of our knowledge, this may be the first demonstration of scattering-dominant OCT contrast agents utilizing structured gold nanoparticles.

bioengineering↗

Gold Nanocages with a Long SPR Peak Wavelength as Contrast Agents for Optical Coherence Tomography Imaging at 1060 nm

There has been growing interest in optical coherence tomography (OCT) imaging at a wavelength of 1060 nm. However, potential contrast agents for OCT imaging at this specific wavelength has not been thoroughly investigated. In this study, we present the synthesis and optical characterization of gold nanocages with a small edge length ([~]65 nm) and a surface plasmon resonance peak around 1060 nm. These nanocages represent a class of potential contrast agents for OCT at 1060 nm. OCT imaging experiments were conducted on phantoms and in vivo mouse tissues using a 1060-nm swept-source OCT system, demonstrating significant enhancement in imaging contrast due to the presence of the gold nanocages. GRAPHICAL ABSTRACTGold nanocages with a long SPR peak wavelength as OCT imaging contrast agents at 1060 nm O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=105 SRC="FIGDIR/small/642209v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@179a727org.highwire.dtl.DTLVardef@1cd1e4eorg.highwire.dtl.DTLVardef@180ce47org.highwire.dtl.DTLVardef@166a779_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗