Fabrication of Nanostructured Polycaprolactone (PCL) Film Using a Thermal Imprinting Technique and Assessment of Antibacterial Function for Its Application

Abstract

In the use of the medical devices, it is essential to prevent the attachment of bacteria to the device surface or to kill the attached bacteria. To kill bacteria, many researchers have used antibiotics or studied nanostructure-based antibacterial surfaces, which rely on mechanical antibacterial methods. Several polymers are widely used for device fabrication, one of which is polycaprolactone (PCL). PCL is biocompatible, biodegradable, easy to fabricate using 3D printing, relatively inexpensive and its quality is easily controlled; therefore, there are various approaches to its use in bio-applications. In addition, it is an FDA-approved material, so it is often used as an implantable material in the human body. However, PCL has no inherent antibacterial function, so it is necessary to develop antibacterial functions in scaffold or film-based PCL medical devices. In this study, process parameters for nanopillar fabrication were established through a simple thermal imprinting method with PCL. Finally, a PCL film with a flexible and transparent nanopillar structure was produced, and the mechano-bactericidal potential was demonstrated using only one PCL material. PCL with nanopillars showed bactericidal ability against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) bacteria cultured on its surface that resulted in membrane damage and death due to contact with nanopillars. Additionally, bacteriostatic results were shown to inhibit bacterial growth and activity of Staphylococcus aureus (S. aureus) on PCL nanostructured columns. The fabricated nanopillar structure has confirmed that mechanically induced antibacterial function and can be applied to implantable medical devices.

Antibacterial and Antifogging Nanopillar Array Films: Targeted Efficacy against Staphylococcus aureus

“…Until now, strategies focused on nanostructures have been harnessed to elicit antibacterial effects through membrane damage. − While this strategy can make bactericidal surfaces, their efficacy diminishes due to the persistence of killed bacteria remaining on the surface as debris, which, in turn, can foster secondary biofilm formation. This limitation underscores the imperative for a hybrid strategy to navigate this obstacle. , Scheme a presents a conceptual depiction of an amphiphilic MPC–nanopillar surface, coating MPC with the nanopillar structures in a unified framework.…”

Advances in lithographic techniques for precision nanostructure fabrication in biomedical applications

“…The authors found that producing these transistors with EHL was simpler and more cost-effective than current methods such as PL and EBL, and has greater potential for applications such as flexible wearable devices [ 285 ]. The ability to pattern the biocompatible polymer polycaprolactone, exemplified by Goldberg Oppenheimer et al, opens avenues for applying these flexible devices to the biomedical industry, including implantable medical devices [ 282 , 286 ]. However, for widespread production and reproducibility in applications such as wearable biosensors, further research is necessary to enhance production techniques to improve the throughput, maintain a consistent nanometer-scale distance between electrodes for uniform structures to ensure reproducibility and explore the patterning of additional biocompatible polymers, thereby expanding its application possibilities.…”

Black silicon spacing effect on bactericidal efficacy against gram-positive bacteria

“…Previous studies on mechanically bactericidal nanostructures have focused on non-uniform and irregular nanostructures in cicada wings and black silicon. Such randomness complicates the analysis of how specific changes in surface morphology affect bactericidal efficacy [48][49][50]. These nanoneedles are tested against Staphylococcus epidermidis (S. epidermidis), which consists of cocci approximately 500-1000 nm in diameter, arranged in clusters [51,52].…”