Early bloodmaterial interfacial events and capillary transport on nanoparticle modified nanofibers

TL;DR

This work tackles the challenge of hemocompatibility for hydrophobic electrospun PCL nanofibers by introducing laser-synthesized oxide-shelled silicon nanoparticles as interfacial modifiers. By configuring the same SiNPs either inside the fiber volume (PAC) or on the fiber surface (SPAC) across multiple loadings, the authors reveal a clear localization-dependent control of early blood wetting and capillary transport. Surface-decorated SPAC variants, especially at high loading, drive rapid wetting, extensive plasma infiltration, and robust imbibition through the fibrous network, while volume-loaded PACs produce more modest effects. These findings provide design principles for tuning the initial blood–material interface in PCL-based dressings and vascular grafts, highlighting the pivotal role of nanoscale interfacial chemistry and capillary transport in determining subsequent hemocompatibility.

Abstract

Electrospun poly(ε-caprolactone) (PCL)nanofibrous mats are widely considered for blood-contacting wound dressings and small-diameter vascular applications; however, their intrinsic hydrophobicity limits rapid wetting and controlled interaction with blood. In this work, we modulate the interfacial response of PCL nanofibers by incorporating oxide-shelled silicon nanoparticles (SiNPs) synthesized by pulsed laser ablation in liquid, a ligand-free approach that avoids organic stabilizers and preserves surface reactivity. Two composite architectures were designed: SiNPs embedded within the fiber bulk (PAC1,4,16) and SiNPs preferentially exposed at the fiber surface (SPAC1,4,16), with systematically increasing nanoparticle loadings. Structural characterization confirmed the retention of a homogeneous fibrous morphology and the targeted nanoparticle distribution. The dynamic interaction with whole blood was quantified using time-resolved contact-angle measurements, complemented by top-view optical microscopy and three-dimensional profilometry of dried droplets. Pristine PCL remained strongly hydrophobic whereas a hydrophilic PCL functionalized with APTES showed rapid spreading. Incorporation of SiNPs within the fiber volume led to only a moderate enhancement of wettability, and dried droplets retained compact morphologies with limited spreading. In contrast, surface-decorated mats displayed a sharp, concentration-dependent transition toward highly wettable behavior: for SPAC16, the contact angle fell below 20, droplet profiles became markedly flattened, and microscopy revealed extended plasma-rich regions surrounding a red-cell-rich core, indicative of pronounced phase separation within the nanofibrous network.

Figures (12)

• Figure 1: Snapshot showing the deposition of a blood droplet onto the substrate using a calibrated micropipette during contact angle measurements.
• Figure 2: Characterization of the silicon nanoparticles. (A): TEM micrograph of a sample ablated in ethanol. (B) Diffraction pattern of the SiNPS. (C) Nanoparticle size distribution
• Figure 3: Characterization of the pure PCL nanofibers. (A): SEM micrograph of the PCL NFs. (B): Size distribution graph. (C) FTIR spectrum.
• Figure 4: Characterization of the NFs functionalized by SiNPs in the volume of the fibers. (A) HR-SEM micrograph in BED-C mode of a PAC-1 sample; (B) HR-SEM micrograph in BED-C mode of a PAC-4 sample; (C) HR-SEM micrograph in BED-C mode of a PAC-16 sample; (D) Average size dispersion of the SiNP-containing samples; (E) FTIR spectrum of a PAC-16 sample.
• Figure 5: Comparison between the ultrasonic deposition of SiNPs on PCL (A) and PA (B) samples.