Biology subjects

O'Brien, F. J.

Publications and source records attributed to O'Brien, F. J..

6 recordsLinked to original sources

bioRxiv2026

Scaffold-mediated delivery of a miRNA-29b mimic mitigates excessive extracellular matrix deposition and matrix contraction in wound healing applications

Disruption of the wound healing cascade can result in pathological outcomes, including fibrosis due to myofibroblast-mediated contraction and collagen deposition. Despite the clinical significance, effective treatments for fibrosis remain limited as current therapies often show inconsistent efficacy, adverse effects, and patient discomfort. Combinatorial therapeutic strategies integrating biomaterial scaffolds with gene delivery have shown promise in regenerative healing. MicroRNAs (miRNAs) are key regulators of fibrotic signalling in cells, including fibroblasts and myofibroblasts. Specifically, miRNA-29b is notable for downregulating pro-fibrotic genes, including collagen type I, reducing ECM accumulation, and limiting fibroblast/myofibroblast overactivation. In this context, the present work develops a collagen-GAG (CG) scaffold platform for delivery of miRNA-29b complexed GET nanoparticles to inhibit fibrosis. Initially, bioinformatic analysis of miRNA-29b validated its involvement in ECM-associated pathways and processes, followed by successful nanoparticle internationalisation in primary dermal fibroblasts. The anti-fibrotic efficacy of the optimised miRNA-29b nanoparticles was subsequently demonstrated by significant reductions in collagen deposition and -SMA expression, both key indicators of myofibroblast differentiation and fibrosis. The optimised miRNA-29b formulation was then incorporated into 3D porous collagen-GAG (CG) scaffolds, which modulated fibrotic gene expression while preserving scaffold structure conducive to fibroblast/myofibroblast infiltration and proliferation. Finally, functional outcomes of seeded TGF-{beta}-stimulated fibroblasts, including reduced matrix contraction, -SMA expression, and ECM deposition, were comparable to those observed in non-fibrotic conditions, thereby confirming the therapeutic potential of scaffold-mediated miRNA-29b delivery. Together, these findings demonstrate that scaffold-mediated miRNA-29b delivery represents a promising anti-fibrotic strategy for wound healing by mitigating myofibroblast activation, limiting matrix contraction, and preventing pathological ECM accumulation.

bioengineering↗

bioRxiv2026

Biomimetic miR-133a inhibitor activated scaffolds optimised for spinal cord repair promote neurite outgrowth and angiogenesis via neuronal cytoskeletal remodelling

Significant challenges in spinal cord injury include the loss of neural tissue, disruption of local vasculature, and intrinsic suppression of actin mobilisation in neurons, together preventing axonal regrowth. Here, we develop an implantable biomimetic microRNA (miR) inhibitor-activated scaffold that combines optimised matrix cues with transcriptomically defined RNA-based modulation of intrinsic neuronal pathways as a platform to support neuronal cell delivery and promote neurovascular repair. First, hyaluronic acid macroporous scaffolds functionalized with collagen-IV and fibronectin supported iPSC-derived neuronal spheroid formation and neurite extension. To identify a neurotrophic target, we performed analysis of public miRNA-mRNA interaction datasets, revealing that miR-133a regulates pathways involved in neuronal actin cytoskeletal organisation. MiR-133a inhibitors were complexed with the cell-penetrating peptide RALA to form nanoparticles, demonstrated >95% scaffold loading efficiency, sustained localised release over 28 days and enhanced neurite outgrowth from motor neurons and iPSC neurons. Bulk RNA-sequencing and transcriptomic analysis of iPSC neurons within the scaffolds demonstrated coordinated upregulation of actin-remodelling, cell-matrix adhesion and metabolic pathways, indicative of a cytoskeletally adaptable neuron. When employed in an ex vivo dorsal root ganglia model, scaffold-mediated miR-133a inhibition promoted neurite extension and integration of delivered iPSC neurons with injured neural tissue. Finally, miR-133a-inhibitor-activated scaffolds upregulated neurovascular genes, increased endothelial cell migration and enhanced blood vessel formation in vivo in a chick embryo assay. These findings identify miR-133a as a neurotrophic target, elucidate the underlying mechanisms of action through transcriptomic analysis and demonstrate that biomimetic scaffold-mediated inhibition of miR-133a can enhance neuronal delivery for multifaceted spinal cord repair applications. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=89 SRC="FIGDIR/small/719922v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@13fcb26org.highwire.dtl.DTLVardef@13239c3org.highwire.dtl.DTLVardef@6e6f5eorg.highwire.dtl.DTLVardef@51ad93_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2025

Scaffold-mediated miRNA-155 inhibition promotes regenerative macrophage polarisation leading to anti-inflammatory, angiogenic, and neurogenic responses for wound healing

Chronic wounds represent a significant clinical challenge due to persistent inflammation and impaired nerve regeneration, both of which delay healing. Conventional treatments often yield limited success and inconsistent outcomes, especially in complex and recurring wounds. Combinatorial strategies that integrate biomaterial scaffolds with gene delivery offer a promising approach to promote tissue repair. MicroRNAs (miRNAs), particularly miRNA-155, have emerged as crucial regulators of wound healing. MiRNA-155 is highly expressed in inflammatory conditions and plays a key role in macrophage activation, polarisation, and nerve regeneration. In this context, this study introduces a miRNA-155 inhibitor-activated scaffold designed to modulate the chronic wound environment by inhibiting miRNA-155. MiRNA-155 inhibitor complexed GET nanoparticles were characterised and incorporated into collagen-glycosaminoglycan (CG) scaffolds. These supported dermal fibroblast and endothelial cell growth while enabling controlled inhibitor release. Scaffold-mediated miRNA-155 inhibition in both non-polarised (M0) and pro-inflammatory (M1) macrophages promoted anti-inflammatory (M2) polarisation. Macrophage secretome analysis showed reduced inflammatory cytokines and increased angiogenic growth factor secretion in both conditions. The regenerative potential of the miRNA-i-activated scaffold via macrophage polarisation was validated through inflammatory and angiogenic functional assays with endothelial cells. In parallel, scaffold-mediated miRNA-155 delivery to dorsal root ganglia (DRG) promoted neurogenic outcomes through enhanced axonal regrowth, essential for the synergistic repair of chronic wounds across the skin-nerve axis. In vivo implantation of miRNA-155 inhibitor-activated scaffolds in chicks demonstrated successful integration without disrupting vascular network formation. Collectively, these findings establish the miRNA-155 inhibitor-activated scaffold as a regenerative platform with anti-inflammatory, pro-angiogenic, and neurogenic outcomes, offering a multifaceted solution for chronic wound healing applications. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=117 SRC="FIGDIR/small/682055v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@1c6a6b6org.highwire.dtl.DTLVardef@eb04f9org.highwire.dtl.DTLVardef@1937f15org.highwire.dtl.DTLVardef@7c70d3_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2025

2D Boron Nanoplatelets as a Multifunctional Additive for Osteogenic, Gram-Negative Anti-Microbial and Mechanically Reinforcing Bone Repair Scaffolds

Two-dimensional boron offers unique advantages in bone tissue engineering, unlocking capabilities that conventional additives struggle to achieve. In this study, we leverage the 2D morphology and intrinsic bioactivity of boron nanoplatelets, incorporated into collagen-based scaffolds, to simultaneously achieve osteogenic, neurogenic, angiogenic, anti-inflammatory, mechanically reinforcing, and anti-microbial effects. We synthesize boron nanoplatelets from non- layered precursors using liquid-phase exfoliation and combine them with collagen to form boron- collagen scaffolds (BColl). Boron significantly reinforces the collagen matrix, beneficial for mechanoresponsive bone cells. Osteoblasts and mesenchymal stem cells exhibit healthy morphology and proliferation on BColl films and scaffolds, with extended culture leading to increased alkaline phosphatase release and significantly increased calcium deposition, indicating enhanced osteogenesis. E. coli viability decreases significantly on BColl films, demonstrating their potential to limit post-implantation infections. Finally, we observe angiogenic, neurogenic and anti-inflammatory effects, with dose-dependent upregulation of vascular endothelial growth factor-A, nerve growth factor-beta and interleukin-10, and downregulation of interleukin-6 highlighting borons potential to drive pro-reparative processes. Taken together, these data showcase borons potential in developing next-generation bone biomaterials, by offering multifunctional benefits to clinically relevant aspects of bone regeneration such as mineralization, angiogenesis, and innervation, while improving the mechanical and anti-microbial properties of natural polymer scaffolds. Graphical Abstract & ToC TextAn ideal bone scaffold would enhance osteogenesis, angiogenesis, and neurogenesis, while preventing inflammation, infection, and stiffness mismatch. 2D materials unlock diverse properties arising from the nanoplatelet morphology, while simultaneously leveraging the intrinsic properties of the material, enabling such multifunctional scaffolds. In this study, we combine 2D boron nanoplatelets with a bioactive collagen matrix to form a multifunctional, versatile bone repair scaffold with osteogenic, angiogenic, neurogenic, anti-inflammatory, and anti-microbial behaviour. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=175 SRC="FIGDIR/small/673512v1_ufig1.gif" ALT="Figure 1"> View larger version (68K): org.highwire.dtl.DTLVardef@1611344org.highwire.dtl.DTLVardef@37f0bcorg.highwire.dtl.DTLVardef@9e044dorg.highwire.dtl.DTLVardef@2c6bf5_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2025

PolyGraph - Flexible, Biocompatible & Electrically Optimised Graphene-Polymer Composites for Next-Generation Neural Interfaces

Neural interfacing materials must deliver exceptional electrochemical performance, while integrating safely with the central nervous system. In this study we develop PolyGraph, a flexible, conductive, and biocompatible graphene-polycaprolactone (PCL) nanocomposite designed to strike this balance, which enables fabrication of conformable multichannel microelectrode arrays. Optimised liquid-phase exfoliation produces conductive, biocompatible PVP-stabilised graphene nanosheets, which are incorporated into PCL to form flexible, processable composites - PolyGraph. This material demonstrates bio- and immuno-compatibility with sensitive primary and iPSC-derived neuronal and glial cells. PolyGraph achieves low impedance ([~]1.6 {Omega} cm2 @ 1 kHz) and high charge injection capacity (11.7 mC/cm2 for a 100 ms pulse), enhanced by NaOH surface roughening and AuPd coating. Leveraging their processability, PolyGraph composites are fabricated into flexible, individually isolated microneedle electrode arrays with biomimetic soft hyaluronic acid backings. These arrays demonstrate bidirectional neural interfacing capabilities, enabling both the delivery of controlled stimulation pulses in physiological buffer and high-resolution neuronal recording in murine brain slices, with machine learning-based event classification. Together, these advances establish PolyGraph as an optimal material platform for next-generation brain-computer interfaces and soft bioelectronic devices. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=109 SRC="FIGDIR/small/673516v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@9beea5org.highwire.dtl.DTLVardef@150be08org.highwire.dtl.DTLVardef@1ec24d2org.highwire.dtl.DTLVardef@658209_HPS_FORMAT_FIGEXP M_FIG C_FIG Graphical Abstract & TOC Text PolyGraph, a flexible graphene-polycaprolactone nanocomposite, unites conductivity, biocompatibility, and processability for next-generation neural interfaces. Fabricated into microneedle arrays with ultra-flexible backings, PolyGraph enables bidirectional neuronal recording and stimulation in brain tissue, advancing brain-computer interface (BCI) and soft bioelectronic applications.

bioengineering↗

bioRxiv2024

3D-printed, biomimetic, conductive MXene-microfiber composite scaffolds enhance the axonal growth-promoting characteristics of electrical stimulation.

No effective treatments are currently available for central nervous system neurotrauma although recent advances in electrical stimulation suggest some promise in neural tissue repair. We hypothesized that structured integration of an electroconductive biomaterial into a tissue engineering scaffold could enhance electroactive signalling for neural regeneration. Electroconductive 2D Ti3C2Tx MXene nanosheets were synthesized from MAX-phase powder, demonstrating excellent biocompatibility with neurons, astrocytes and microglia. To achieve spatially-controlled distribution of these MXenes, melt-electrowriting was used to 3D-print highly-organized PCL micro-meshes with varying fibre spacings (low-, medium-and high-density), which were functionalized with MXenes to provide highly-tunable electroconductive properties (0.081{+/-}0.053-18.87{+/-}2.94 S/m). Embedding these electroconductive micro-meshes within a neurotrophic, immunomodulatory hyaluronic acid-based extracellular matrix (ECM) produced a soft, growth-supportive MXene-ECM composite scaffold. Electrical stimulation of neurons seeded on these scaffolds promoted neurite outgrowth, influenced by fibre spacing in the micro-mesh. In a multicellular model of cell behaviour, neurospheres stimulated for 7 days on high-density MXene-ECM scaffolds exhibited significantly increased axonal extension and neuronal differentiation, compared to low-density scaffolds and MXene-free controls. The results demonstrate that spatial-organization of electroconductive materials in a neurotrophic scaffold can enhance repair-critical responses to electrical stimulation and that these biomimetic MXene-ECM scaffolds offer a promising new approach to neurotrauma repair.

bioengineering↗