Biology subjects

Lozano, N.

Publications and source records attributed to Lozano, N..

6 recordsLinked to original sources

bioRxiv2026

Plasma membrane-associated graphene oxide as aplatform for modulating signalling through cell-surfacereceptors: an integrin-focused proof-of-concept study

Graphene oxide (GO) has primarily been investigated as a carrier for intracellular delivery of therapeutic molecules. In previous work, we identified a cell type-dependent interaction pattern in which GO remained predominantly associated with the plasma membrane of cancer cells but was internalised by non-cancerous epithelial cells. Here, we explored whether plasma membrane-associated GO can be used as a platform to present bioactive ligands and influence cell-surface receptor signalling in cancer cells. To test this hypothesis, we targeted integrin receptors at the plasma membrane in glioblastoma cell models using an RGD-containing peptide non-covalently complexed with GO. We assessed GO-peptide interactions, cellular interactions/uptake, motility, and focal adhesion signalling readouts. Peptide association was quantified using a 2,4,6-trinitrobenzene sulfonic acid (TNBSA) assay, and GO was characterised by atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and colloidal measurements. Immediately after complexation, ~70% of RGD was associated with GO. Peptide association increased the nitrogen signal and shifted the principal GO XRD peak while retaining nanosheet morphology. Biological responses were examined in U87 and U251 glioblastoma cells with different integrin-positive fractions, and in non-cancerous BEAS-2B bronchial epithelial cells. Confocal microscopy showed that GO and GO:RGD remained predominantly localised on the plasma membrane in U87 and U251 cells, whereas greater intracellular localisation was observed in BEAS-2B cells. Importantly, GO:RGD significantly reduced key indicators of cell motility: cell velocity in U87 and U251 cells, with trajectory and mean-square-displacement analyses supporting restricted cellular movement. Free RGD had no significant effect, while GO alone produced a smaller reduction in motility only in U251 cells. No treatment significantly altered BEAS-2B motility. Flow cytometry also showed a reduced pFAK-associated signal in GO:RGD-treated U87 cells. These findings establish a proof of concept that the cell-line-dependent plasma membrane localisation of GO can be exploited as a membrane-associated nano-bio interface for cell-surface-active ligands, opening the way for the development of GO-based platforms that modulate receptor-mediated signalling and cell behaviour.

cell biology↗

bioRxiv2025

Targeting therapeutic nanoparticles to the glioblastoma resection margin by harnessing post-operative spatiotemporal blood-brain barrier disruption

Resection surgery is the first-line therapy for glioblastoma (GBM) that is performed in >70% of patients, typically within days of suspected diagnosis. Current protocols for follow-on chemoradiotherapy have shown only modest efficacy in eliminating residual disease, leading to inevitable tumour recurrence. There remains a need for new approaches to swiftly and effectively treat post-operative residual disease to prevent the rapid early progression of recurrent GBM. Using syngeneic preclinical models of glioblastoma resection, we identified a spatially and temporally restricted window of blood brain barrier (BBB) disruption localised to the resection margin, during the immediate (15 min) and early (48-72h) postoperative periods. Intravenous administration of fluorescently labelled, clinically-used liposome nanoparticles during these periods demonstrated that selective accumulation at the postoperative resection margin, while largely being excluded from areas of the brain with an intact BBB, could be achieved. Confocal analysis confirmed the presence of extravasated nanoparticles within the margin parenchyma which largely interacted with microglial populations closely associated with residual tumour cells. Exploiting this, we performed intravenous administration of doxorubicin-loaded liposomes (DOX-Lipo) coinciding with the peak of postoperative BBB disruption and demonstrated both enhanced chemotherapy delivery and consequently complete inhibition of tumour recurrence from a single administration. Overall, this work underscores the importance of timing concomitant chemotherapy to the post-operative timeframe and demonstrates that clinically-used liposomal nanomedicines could be readily repurposed for early post-operative therapy in aggressive brain tumours.

pharmacology and toxicology↗

bioRxiv2024

Interplay between material properties and cellular effects drives distinct pattern of interaction of graphene oxide with cancer and non-cancer cells

Understanding how graphene oxide (GO) interacts with cells is crucial for its safe and efficient biomedical applications. Despite extensive research, a systematic investigation using a panel of cell lines, thoroughly characterized label-free nanomaterials, and complementary analytical techniques is lacking. Here, we examined the uptake of thin GO sheets with distinct lateral dimensions in 13 cell lines: 8 cancer (HeLa, A549, PC3, DU-145, LNCaP, SW-480, SH-SY5Y, U87-MG) and 5 non-cancer (BEAS-2B, NIH/3T3, PNT-2, HaCaT, 293T), using confocal microscopy, transmission electron microscopy, and flow cytometry. Our results reveal a striking difference in GO uptake: non-cancer cells internalized GO efficiently, while in cancer cells, GO predominantly interacted with the plasma membrane, showing minimal to no internalization. Comparison to other nanomaterials (polystyrene beads and graphene flakes) confirmed that cancer cells internalize materials similarly to non-cancer cells, indicating GO-specific interactions. We identified that GO thickness plays a pivotal role in this differential uptake. Additionally, GO disrupted the actin cytoskeleton, impairing migration in cancer but not in non-cancer cells. We propose that thin GO sheets act as a cue upon interaction with the plasma membrane of cancer cell lines, subsequently inducing actin filaments disruption leading to impaired endocytosis, migration activity, and reduced capacity of cancer cells towards GO uptake.

cell biology↗

bioRxiv2023

Engineering the glioblastoma microenvironment using TLR7/8 agonist-complexed graphene oxide nanosheets

The glioblastoma (GBM) microenvironment is characterised as immunologically cold, with immunosuppressive components that compromise the efficacy of current immunotherapies. Tumour associated macrophages and microglia (TAMMs) that are activated towards an immunosuppressive, pro-tumoral state have been identified as major contributing factors to the coldness of GBM, while further promoting tumour progression and resistance to therapy. Based on this understanding, strategies such as macrophage reprogramming have been explored but have so far been limited by poor delivery and retention of reprogramming agents to the target cell populations within the GBM microenvironment. Consequently, clinical efficacy of such approaches has thus far shown limited success. Two-dimensional, graphene oxide (GO) nanosheets have been demonstrated to spread readily throughout the entire tumour microenvironment following a single intratumoral injection, interacting primarily with TAMMs. The current study aimed to investigate whether the immunosuppressive character of TAMMs in GBM can be ameliorated using GO sheets as a vector system to selectively deliver a TLR7/8 agonist (Resiquimod, R848), into these populations. GO enhanced the activity of R848 and induced the expression of M1-like markers on bone marrow derived macrophages in vitro. Using multi-parameter flow cytometry and histological analysis in a syngeneic, orthotopic mouse model of GBM, we observed that a single intratumoral injection of GO:R848 complex significantly elevated the proportion of macrophages and microglia expressing MHCII, TNF and CD86 (associated with a pro-inflammatory, anti-tumoral state), while downregulating their expression of the M2 markers ARG1 and YM1 (associated with an anti-inflammatory, pro-tumoral state). This local complex administration inhibited tumour progression and significantly reduced tumour burden. These data illustrate that immunomodulatory GO nanosheets can effectively alter the immune landscape of GBM and modulate the wider GBM microenvironment. ToC Image O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=126 SRC="FIGDIR/small/558196v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@199bdb0org.highwire.dtl.DTLVardef@7473c3org.highwire.dtl.DTLVardef@15c14c6org.highwire.dtl.DTLVardef@57fdeb_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2023

Engineering of a graphene oxide-based two-dimensional platform for immune activation and modulation

Nanoscale-based tools for immunomodulation are expected to offer a rich battery of options for more targeted and safer approaches to achieve clinically effective manipulation of the local and systemic immune environment. In this study, we aimed to design nanoscale constructs based on graphene oxide (GO) nanosheets as platform carriers for the TLR7/8 agonist Resiquimod (R848). The non-covalent complexation of R848 molecules on the GO surface resulted in stable complexes by preserving their biological activity. The physicochemical properties, molecular quantification, as well as the overall performance of the complex were systematically investigated. We hypothesized the formation of GO:drug nano-constructs with strong colloidal stability over time, due to the strong {pi}-{pi} interactions between the R848 molecules and the GO surface, and identified that R848 loading efficiency consistently ranged around 75% (of starting molecules), quantified by HPLC and UV-Vis. The 2D morphology of the thin nanosheets was retained after complexation, determined by various (AFM and SEM) microscopic techniques. Based on the surface physicochemical characterization of the complexes by Raman, FTIR, XPS, and XRD, the formation of non-covalent interactions among the GO surface and the R848 molecules was confirmed. Most importantly, GO:R848 complexes did not compromise the biological activity of R848, and effectively activated macrophages in vitro. Collectively, this study demonstrates that thin GO sheets can act as platforms for the non-covalent association with small TLR7/8 agonist molecules, forming stable and highly reproducible complexes, that could be exploited as effective immunomodulatory agents.

bioengineering↗

bioRxiv2023

Functioning human lung organoids model pulmonary tissue response from carbon nanomaterial exposures

Human lung organoids (HLOs) are increasingly used to model development and infectious diseases, however their ability to recapitulate functional pulmonary tissue response to nanomaterial (NM) exposures has yet to be demonstrated. Here, we established a lung organoid exposure model that utilises microinjection to present NMs into the lumen of organoids. Our model assures efficient, reproducible and controllable exposure of the apical pulmonary epithelium, emulating real-life human exposure scenario. By comparing the impact of two well studied carbon-based NMs, graphene oxide sheets (GO) and multi-walled carbon nanotubes (MWCNT), we validated lung organoids as tools for predicting pulmonary NM-driven responses. In agreement with established in vivo data, we demonstrate that MWCNT, but not GO, elicit adverse effects on lung organoids, leading to a pro-fibrotic phenotype. Our findings reveal the capacity and suitability of HLOs for hazard assessment of NMs, aligned with the much sought-out 3Rs (animal research replacement, reduction, refinement) framework.

pharmacology and toxicology↗