Journal: Materials Today Bio

Article Title: A blood-brain barrier model based on flexible tubes to tailor the biophysical and chemical environment for drug delivery testing

doi: 10.1016/j.mtbio.2026.103307

Figure Lengend Snippet: Fabrication and endothelialization of a tubular BBB model. (A) Schematic representation of the blood-brain barrier. (B) 3D illustration of the tubular and flexible biomaterial lined with brain endothelial cells. (C) Fabrication strategy for the tubular biomaterial, based on membrane formation via polyelectrolyte complexation, including encapsulation of bEnd.3 cells within the polyanion-rich phase and subsequent culture of the tubular constructs for 7 days to enable endothelial attachment and maturation on the membrane surface. (D) Endothelialization of the tubular biomaterial: (i) representative image of the flexible, closed-ended tubular construct; (ii) live/dead staining (calcein-AM/EthD-1) demonstrating endothelial cell attachment and proliferation; (iii) live/dead staining confirming uniform cell coverage of the membrane. (E) Structural and cytoskeletal organization of the endothelial layer after 7 days in culture: (i) immunofluorescence staining of nuclei, F-actin, and the tight junction protein ZO-1, including merged images; (ii) transverse cross-section of the endothelialized tubular construct; (iii) longitudinal cross-section of the endothelialized tubular construct.

Article Snippet: Murine brain endothelial cells (bEnd.3, ATCC® CRL-2299TM) were obtained from the American Type Culture Collection (ATCC).

Techniques: Membrane, Encapsulation, Construct, Staining, Cell Attachment Assay, Immunofluorescence

Journal: Materials Today Bio

Article Title: A blood-brain barrier model based on flexible tubes to tailor the biophysical and chemical environment for drug delivery testing

doi: 10.1016/j.mtbio.2026.103307

Figure Lengend Snippet: Functional characterization of the endothelialized tubular BBB model. (A) Representative live/dead fluorescence images of endothelialized tubular biomaterials at day 1, 5, and 7 in culture, stained with calcein-AM (live cells, green) and ethidium homodimer-1 (EthD-1; dead cells, red), showing progressive endothelial attachment, proliferation, and formation of a confluent monolayer over time. (B) Apparent permeability coefficients ( Papp ) of FITC-dextran (4 kDa and 2000 kDa) across acellular control tubes and endothelialized tubes (tube w/bEnd.3), demonstrating significantly reduced permeability upon endothelialization. (C) Schematic representation of the experimental setup for impedance measurements. (D) Electrical impedance spectroscopy of tubular constructs: (i) impedance magnitude ( Z ) as a function of frequency for acellular control and endothelialized tubes; (ii) quantification of impedance values at selected frequencies (5, 10, and 15 kHz), showing significantly higher impedance in endothelialized tubes compared to acellular controls, indicative of enhanced barrier integrity. (E) Drug permeability assessment across the tubular BBB model: (i) doxorubicin and (ii) temozolomide concentrations measured in the receiving compartment over time for acellular control and endothelialized tubes, demonstrating restricted transport in the presence of the endothelial barrier. Data are presented as mean ± SD; statistical significance is indicated (∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, ∗∗∗∗ p < 0.0001; ns: not significant). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Article Snippet: Murine brain endothelial cells (bEnd.3, ATCC® CRL-2299TM) were obtained from the American Type Culture Collection (ATCC).

Techniques: Functional Assay, Fluorescence, Staining, Permeability, Control, Impedance Spectroscopy, Construct

Journal: Materials Today Bio

Article Title: A blood-brain barrier model based on flexible tubes to tailor the biophysical and chemical environment for drug delivery testing

doi: 10.1016/j.mtbio.2026.103307

Figure Lengend Snippet: Fabrication and functional characterization of hBMECs-endothelialized tubular BBB models. (A) Schematic illustration of tubular biomaterial fabrication via polyelectrolyte complexation, including membrane formation with encapsulated human brain microvascular endothelial cells (hBMECs). (B) Representative 3D reconstruction of an hBMECs-endothelialized tubular construct. (C) Immunofluorescence images showing endothelial organization within the tubular construct after 7 days in culture, including nuclei (blue), F-actin (red), and merged views. (D) Drug transport assessment across the tubular BBB model: (i) doxorubicin and (ii) temozolomide concentrations measured over time for acellular control and hBMECs-endothelialized tubes. (E) Apparent permeability coefficients ( Papp ) of FITC–dextran (4 and 2000 kDa) across acellular control tubes, normal endothelialized tubes, and compressed endothelialized tubes. (F) Representative 3D immunofluorescence image showing ZO-1 distribution in an endothelialized tubular construct subjected to mechanical compression. (G) Electrical impedance spectroscopy showing impedance magnitude ( Z ) as a function of frequency for normal endothelialized tubes, compressed endothelialized tubes, and acellular controls. (H) Quantification of impedance values at selected frequencies (5, 10, and 15 kHz), demonstrating reduced barrier integrity upon mechanical compression. Data are presented as mean ± SD; statistical significance is indicated (∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001, ∗∗∗∗ p < 0.0001; ns: not significant). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Article Snippet: Murine brain endothelial cells (bEnd.3, ATCC® CRL-2299TM) were obtained from the American Type Culture Collection (ATCC).

Techniques: Functional Assay, Membrane, Construct, Immunofluorescence, Drug Transport Assay, Control, Permeability, Impedance Spectroscopy