What happens when a piezoelectric polymer fiber is mixed with four different conductive materials? The result is not one universal winner: fiber size, charge transport, and cell response shift dramatically with the additive. Electroconductive polymers have garnered significant attention because of their unique combination of electrical conductivity, mechanical, and chemical properties.

That combination makes them suitable for applications in electronics, energy storage, and sensing, while research also explores electroconductive polymeric composites for biomedical use. Despite these efforts, many questions remain about optimizing polymer properties for specific applications such as bioelectronics.

The development of new electroconductive polymers and materials with improved performance remains important, particularly where high performance and stability are required. Embedding these materials into nanofibers has the potential to revolutionize biotechnology and provide a foundation for optimizing electroconductive polymers with piezoelectric platforms.

The study therefore compares piezoelectric PVDF-TrFE fibers containing CuO, P3HT, CuPc, and MB to investigate correlations among electroconductive properties, morphology, and in vitro response. The nanofibers used PVDF-TrFE dissolved in tetrahydrofuran at a thirteen weight-percent solution, with CuO, P3HT, CuPc, and MB as active materials.

Composite fibers were formed by adding a selected amount of active component for every one point five grams of thirteen weight-percent PVDF-TrFE in tetrahydrofuran, with experimental amounts shown in Table 1. The solutions were electrospun through a twenty-three gauge syringe at seventeen kilovolts and three hundred microliters per hour, then collected on a three-hundred-rpm mandrel thirteen centimeters away.

Table one lists the formulations used to make PVDF-TrFE composite solutions with four active components: P3HT, copper phthalocyanine, methylene blue, and CuO. It reports each component’s weight, the amount of thirteen-weight-percent PVDF-TrFE in THF, and the resulting composite-solution concentration; the listed active-component weights range from one point four to ten point nine milligrams.

These specifications define the compositions later used to fabricate and compare electroactive nanofibers. Figure one combines a photograph of the differently colored PVDF-TrFE membranes with SEM views of pure PVDF-TrFE and composites containing CuO, MB, P3HT, and CuPc.

The micrographs show fibrous networks distributed across the collector, with a slight preferential alignment visible in each sample. This qualitative comparison matters because it links the visible color changes to the embedded active phase while checking that electrospinning produces broadly homogeneous fibrous membranes for later electrical evaluation.

Figure two compares SEM images of pure PVDF-TrFE nanofibers with composites containing CuO, CuPc, P3HT, and methylene blue, alongside an EDS spectrum identifying elemental signals. The images show fibrous networks with differences in apparent fiber morphology and packing, while the paper notes a generally homogeneous deposition with slight preferential alignment.

This matters because the composite phase influences fiber structure and charge-transport behavior, with methylene blue and CuPc discussed in relation to redox transfer and charge-carrier hopping. Figure three quantifies the average diameters of pure PVDF-TrFE nanofibers and composites containing copper oxide, phthalocyanine, P3HT, or methylene blue, using image analysis.

The plotted points, with error bars, show how fiber size varies across these formulations. This matters because the paper relates fiber diameter to charge-transport behavior, noting that methylene blue and copper phthalocyanine follow the thinner-fiber pattern associated with their reported conductivity mechanisms.

Figure four shows current–voltage curves for PVDF-TrFE nanofibers containing P3HT, CuO, CuPc, or methylene blue, with current plotted against applied voltage. The curves reveal distinct electrical responses: CuO remains close to zero current across the voltage range, while methylene blue and CuPc display more pronounced, nonlinear behavior.

This matters because the authors relate these responses to the active components’ intrinsic charge-transport mechanisms and their interaction with the PVDF-TrFE matrix. The current–voltage result is related to the intrinsic electrical properties of the active components and their interaction with the PVDF-TrFE matrix.

MB and CuPc composites had moderate conductivity: MB exhibited a redox electron transfer mechanism, while CuPc used a charge carrier hopping mechanism. CuO and P3HT composites had poor conductivity in air, with electron and hole hopping mechanisms, respectively.

Cytotoxicity was evaluated with the XTT assay at twenty-four and seventy-two hours, using L929 cells seeded onto PVDF, P3HT, MB, CuO, and CuPc fibers, with the cell culture plate as a control. The XTT procedure replaced the culture medium, added XTT solution, incubated the samples for four hours, and measured the supernatant at four hundred fifty nanometers.

The assay depended on mitochondrial enzymes reducing XTT into soluble formazan dye, and the resulting amount of formazan dye was directly proportional to the number of viable cells. For proliferation tests, six times ten to the third cells per well were seeded onto P3HT, MB, and CuPc fibers and evaluated at one, three, and seven days using XTT.

The in vitro tests first investigated cell adhesion on PVDF-TrFE fibers and composites containing CuO, P3HT, CuPc, and MB at twenty-four and seventy-two hours. Results were presented relative to the control, which represented one hundred percent cell viability, and after twenty-four hours more than sixty percent of cells were viable in every case.

After seventy-two hours, CuO showed a cytotoxic effect on L929 cells compared with fibers without active materials, so the CuO group was excluded from the next assay. Figure five compares L929 cell viability on PVDF-TrFE fibers and fibers containing P3HT, MB, CuPc, or CuO after twenty-four and seventy-two hours, normalized to TCP as one hundred percent viability.

At twenty-four hours, every sample retains more than sixty percent viability, while the seventy-two-hour CuO condition is marked as cytotoxic relative to the unmodified fibers. This matters because it identifies how the embedded materials affect short-term cell compatibility.

Figure six shows confocal images of L929 cells adhering to electrospun PVDF-TrFE fibers after twenty-four hours, with P3HT in panel a, MB in panel b, and CuPc in panel c. Blue staining marks nuclei, while green marks cell bodies, making both cell presence and morphology visible.

The authors report comparable density and similar morphology across the three materials, while noting a higher presence of nuclei in the P3HT-loaded sample, supporting the subsequent proliferation results. Cell proliferation was evaluated after one, three, and seven days, and the results confirmed the trend observed in the in vitro tests.

P3HT and MB fibers showed good cell proliferation compared with CuPc fibers. P3HT and CuPc fibers increased in proliferation after three days but stopped proliferating after seven days. MB fiber proliferation remained similar from the first to the third day and increased after seven days.

Figure seven tracks L929 fibroblast proliferation after one, three, and seven days on electrospun PVDF fibers containing P3HT, MB, or CuPc. The XTT assay, normalized to PVDF fibers as the positive control, shows distinct time-dependent profiles: P3HT increases by day three and then remains similar at day seven, CuPc also rises by day three before leveling off, while MB remains similar from day one to day three and increases by day seven.

Asterisks mark statistically significant differences. The results demonstrated good biocompatibility of the composite meshes, which successfully supported fibroblast adhesion and proliferation. The study identifies antibacterial response as a possible direction for further investigation, including potential physical filtration or static entrapment of bacteria.

The study explored the morphology and in vitro response of electroconductive composite nanofibers for biomedical applications. Blending PVDF-TrFE with CuO, P3HT, CuPc, and MB produced unique combinations of electrical conductivity, biocompatibility, and other desirable properties.

Morphological analysis showed that fiber size was affected by the type of electroconductive phase used. The in vitro assays demonstrated a tunable response in cell viability and proliferation, with P3HT-loaded fibers showing the most favorable interaction described in the conclusion.

The composite fibers produced tunable morphology, electrical behavior, and biological response. Among the tested materials, P3HT-loaded fibers showed the most favorable fibroblast interaction, while CuO raised a cytotoxicity concern after seventy-two hours.