Biology subjects

Dalton, P. D.

Publications and source records attributed to Dalton, P. D..

3 recordsLinked to original sources

bioRxiv2025

Melt Electrowritten Scaffold-Reinforced Affibody-Conjugated Hydrogels for Controlled Bone Morphogenetic Protein-2 Delivery

Bone morphogenetic protein-2 (BMP-2) is clinically used to promote bone regeneration but suffers from uncontrolled release when delivered from collagen sponges, necessitating high doses that can cause adverse effects. Hydrogels offer tunable protein release but are limited by weak mechanics and poor stability during storage and handling. Here, we introduce a two-part protein delivery platform that integrates mechanical reinforcement with affinity-controlled protein release. We developed a melt electrowritten (MEW) scaffold-reinforced, affibody-conjugated polyethylene glycol maleimide (PEG-mal) hydrogel for affinity-controlled BMP-2 delivery. MEW scaffolds improved hydrogel handling, compressive resistance, and stability during lyophilization and rehydration, without altering bulk stiffness. Engineered BMP-2-specific affibodies provided affinity-based control over BMP-2 release. This ability to control BMP-2 release was preserved after lyophilization and rehydration of the hydrogels. In vivo, affibody conjugation of high-affinity affibodies to the hydrogels significantly enhanced BMP-2 retention in subcutaneous implants, while MEW reinforcement significantly increased bone volume and defect bridging in rat femoral bone defects. This affibody-conjugated, MEW scaffold-reinforced hydrogel system effectively integrates mechanical reinforcement with tunable protein-material affinity interactions, advancing hydrogel-based delivery strategies for BMP-2 and other protein therapeutics in musculoskeletal repair.

bioengineering↗

bioRxiv2025

Melt Electrowritten Microfiber-Hydrogel Composite Scaffolds for Aligned Muscle Tissue Engineering

Effective regeneration of skeletal muscle with highly aligned fiber architecture remains a significant challenge in tissue engineering. Structural alignment of muscle constructs along with mechanical integrity are crucial for effective engineering of grafts and microphysiological systems. This study engineered a novel composite microfiber-hydrogel platform using melt-electrowriting (MEW) to fabricate high precision microfiber scaffolds from poly({varepsilon}-caprolactone). Three MEW scaffold designs (Isotropic, Aligned T with perpendicular reinforcements, and Aligned X with angled fiber bridges) were developed and fabricated into composite scaffolds with collagen hydrogels and seeded with myoblasts. Aligned X scaffolds with cross-bridge reinforcements exhibited enhanced mechanical strength and continuous alignment without structural interruption that led to highly aligned and multinucleated cellular organization. The incorporation of collagen hydrogel in composite constructs improved cell seeding efficiency, viability, and metabolic activity compared to scaffolds alone. All scaffold designs provided fiber reinforcement that prevented hydrogel contraction over extended culture periods. Critically, the Aligned X composite constructs significantly increased myoblast differentiation and myotube maturation, evidenced by increased myosin heavy chain expression and myotube diameter. Overall, this composite microfiber-hydrogel approach provides a scalable, structurally stable, and highly aligned platform tailored for enhanced muscle tissue engineering applications, representing an advancement towards addressing clinical challenges associated with muscle injuries.

bioengineering↗

bioRxiv2025

Hyaluronic Acid-Coated Melt Electrowritten Scaffolds Promote Myoblast Attachment, Alignment, and Differentiation

PurposeIn muscle tissues, anisotropic cell alignment is essential for optimal muscle fiber development and function. Biomaterials for muscle tissue engineering must guide cellular alignment while supporting cell proliferation and myogenic differentiation. MethodsHere, we describe the fabrication of a tissue-engineered construct consisting of a scaffold of aligned poly({varepsilon}-caprolactone) (PCL) microfibers coated in a dynamic covalent hydrazone crosslinked hyaluronic acid (HA) hydrogel to support myoblast attachment, myoblast alignment, and myotube formation. Norbornene modification of HA further enabled functionalization with fibronectin-derived arginine-glycine-aspartic acid (RGD) peptide. Scaffolds were fabricated using melt electrowriting (MEW), a three-dimensional (3D)-printing technique that uses stabilization of fluid columns to produce precisely aligned polymeric microfibers. We evaluated C2C12 mouse skeletal myoblasts cultured on non-coated, HA-coated, and HA-RGD-coated MEW scaffolds with fiber diameters of 10 {micro}m, 20 {micro}m, and 30 {micro}m using immunocytochemistry and creatine kinase activity assays. We further evaluated the mechanical properties of 20 {micro}m fiber scaffolds and their effect on myogenic gene expression and alpha-actinin protein expression of C2C12 myoblasts undergoing differentiation. ResultsHA-coated and HA-RGD-coated scaffolds increased attachment of C2C12 myoblasts on all fiber diameters compared to non-coated scaffolds, with HA-RGD-coated scaffolds demonstrating the highest cell attachment. All scaffolds supported cellular alignment along the fibers. Cells differentiated on scaffolds showed anisotropic alignment with increased myotube formation on HA-coated and HA-RGD-coated scaffolds as demonstrated by myosin heavy chain (MHC) staining and by the presence of striations on HA-coated scaffolds visualized with alpha-actinin staining. Increased creatine kinase activity and myogenic gene expression on day 5 further indicated myotube formation on all scaffolds, with HA-coated scaffolds significantly increasing the expression of several key myogenic markers. ConclusionThis unique combination of tunable biophysical and biochemical cues enables the creation of a biomimetic tissue engineered scaffold, providing a platform for new therapeutic approaches for muscle regeneration.

bioengineering↗