Chronic wounds are injuries to the skin and subcutaneous tissue that do not heal within the expected timeframe despite appropriate treatment and often tend to recur. To improve the quality of life of affected individuals, there is an increasing need for innovative therapeutic solutions that can enhance tissue regeneration. One promising strategy involves the use of biocompatible piezoelectric materials, which generate electrical voltage in response to mechanical stimulation and enable localized electrostimulation without the need for external electrodes, thereby activating natural healing processes.
The aim of this master’s thesis was to develop an advanced, fully organic piezoelectric material based on poly-L-lactic acid (PLLA) in the form of nanofibers, intended to serve as a functional wound dressing with dual functionality: electrostimulation of damaged tissue and promotion of regeneration due to its biomimetic structure. To enhance the piezoelectric response, the material was modified through the incorporation of Lacticaseibacillus paracasei, a lactic acid bacterium that naturally produces polyhydroxybutyrate (PHB), a crystalline biopolymer capable of acting as a nucleation site during nanofiber formation.
In the experimental part, we confirmed PHB production by isolated L. paracasei using fluorescent staining, spectrophotometric quantification, and FTIR analysis. Stress induction during bacterial cultivation led to a statistically significant increase in PHB accumulation. The crystallinity of PHB following slow drying was verified by X-ray diffraction analysis. Oriented nanofibers were successfully fabricated from PLLA and the bacteria, with samples containing stress-stimulated bacteria exhibiting a higher piezoelectric response compared to unmodified or control samples with non-stimulated bacteria. The material also showed good biocompatibility, as nanofibers with incorporated bacteria did not negatively affect the viability of human cells.
The results demonstrate that incorporating stress-stimulated bacteria with crystalline PHB can enhance the piezoelectric properties of the material without compromising its biocompatibility. Therefore, the developed dressing represents a significant step toward the creation of biodegradable, functionally active piezoelectric biomaterials that could contribute substantially to the modern treatment of chronic wounds.
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