Our study introduces a new method for label-free super-resolved polarimetry on nanomaterials, compatible with in-situ analysis. Integrating Image Scanning Microscopy (ISM) with polarimetry techniques, we achieve remarkable resolutions down to 90 nm while acquiring polarization information. Overcoming limitations associated with fluorophores in challenging materials, our approach facilitates quantitative measurements of optical properties. Applied successfully to nanostructured surfaces created by femtosecond lasers and boron nitride nanotubes, our work showcases the versatility of this methodology.
Since a wide variety of microscopic living forms in contact with medical implant in human body are known to be sensitive and reactive to the surface topography, it is of active interest to optimize the implant surface of for desired integration. Ultrafast laser is a powerful tool for modifying the surface of medical implants, at the micro- /nano-scale, for either improving or limiting living tissues adhesion ability. Laser processing and living microorganisms’ response to laser texturing are discussed. Bacteria reduction and human cells adhesion at implant surfaces are reviewed in connection with ultrafast laser induced surface micro- / nanostructures.
Femtosecond laser allows the production of THz radiation that is very promising for the imaging of various tissues and, namely, for in vivo cancer detection. Despite numerous very convincing experimental demonstrations, the mechanisms involved in image formation are still under discussion. In this paper, based on modeling, we analyze the major physical processes involved in THz laser interactions with tissues, namely with skin. Particular attention is given to the mechanisms involved in integrated THz imaging with NIR femtosecond laser illumination. An effective medium approach is found to be helpful. The difference in water fraction, pores, and additional nanoparticles and nanorods are shown to play a role in the considered non-invasive optical imaging of skin cancer.
In this presentation, we will show the latest advances in the context of the European H2020 Horizon project LaserImplant. Functionalized surfaces by ultrashort laser texturing were developed with the aim of improving the biocompatibility and efficiency of medical screws. Both osteoblast cell repellent surfaces as well as surfaces promoting osteogenesis were studied and characterized by bone cells’ growth and wettability tests.
Beam delivery strategies were anticipated for future industrial requirements. Compromises had to be found to implement different textures in one unique solution. Targeted processing times as well as quality robustness were at stake for complex cylindrical shapes with multiple dimensions. Upscaling experiments put in evidence thermal effects due to energy deposition acceleration. Solutions were finally found to overcome speed limitations by selecting dedicated optical systems together with adapted synchronized processes.
In dentistry, implantation failures of dental implants are primarily due to a poor osteointegration, and complications induced by peri-implantitis. For that reason, a strong bacteria resistance, a fast osseointegration, and a good adhesion of the gingival tissues to the implant surface are essential for a successful implantation, comfort and safety of the patient in question. We showcase that a fine-tuning of ultrafast laser-induced surface structures would improve the implantation successful rate by rendering dental implant surfaces with triple-functionality: repellent for saliva bacteria for the upper part of the dental implant (which is exposed to mouth water, attractive to gingival fibroblasts for the middle part of the dental implant (which interfaces with gum tissue) to prevent bacteria penetration, and fast osseointegration for the lower part of the dental implant which is located in the jaw bone environment.
Laser processing of material surfaces has been very known for the last five decades. Femtosecond LIPSS, are created generally on the surface, they could be classified into two groups depending on the periodicity of the structures: LSFL showing a periodicity lower than the incident wavelength (λ_l), and HSFL with a periodicity well below λ_l that could sit below the optical diffraction limit. In this paper, we show an unprecedented resolution of a noninvasive label-free optical method to observe such structures, that does not require a priori knowledge of the surface. We demonstrate that using a modified reflectance confocal microscope reflection (CMR), the characterization of HSFL(̴Λ_HSFL∽120 nm @ λ_l=257 nm) is possible and efficient. These results, pave the way toward a new, better, and more resolved optical technique to observe nanostructures below the diffraction limit.
The use of ultrafast Cylindrical Vector Vortex beams in laser-matter interaction permits to harness new ablation features from inhomogeneous distributions of polarization and beam energy distribution geometry. As a consequence, the ablation process can yield higher ablation efficiency compared to the conventional Gaussian beams. Cylindrical Vector Vortex beams prevent surface quality degradation during ablative processes. When processing stainless steel and titanium, the average surface roughness obtained by deploying Cylindrical Vector beam is up to 94% lower than the Gaussian case, and the processing efficiency is 80% higher.
Femtosecond lasers emit short pulses whose temporal width is in the range of less than a picosecond to a few femtoseconds (fs), thereby enabling extremely high peak-power machining with minimum thermal damages. Herein we employed femtosecond laser pulses as a versatile tool for surface processing of textiles made of 2 polymers commonly used in textile industry, Polyethylene terephthalate (PET), and Polyamide66 (PA66). This work focuses on a comparison of ultraviolet (UV, 257 nm) and infrared (IR, 800 and 1030 nm) femtosecond laser irradiation at the surface of the polymers PET and PA66, possible hybridization with chemical grafting, as well as the resulting liquid repellency from different process scenarios. The study highlights the different responses of the polymers to the laser irradiations and possible routines for surface functionalization of the textiles.
Titanium based dental implant suffer sometimes from failure due to lack of osseointegration in the jaw bone. In this work, we study the generation of Laser Induced Periodic Structures (LIPSS) using three different femtosecond lasers with wavelengths of 1030,515 & 257nm. Fully covered Titanium alloy (Ti6AlV) samples with different LIPSS periodicities are produced and wettability tests are performed prior and post sterilization of the samples. Finally, a comparison between the effect of different LIPSS on the cell adhesion is performed using mesenchymal stem cells to identify the best pattern for enhanced cell adhesion.
Medical implants are frequently used to replace damaged organs, structures and tissues in human body. It is essential to ensure a perfect implantation hence paramount to optimize surface topography of the implants for desired integration. For dental implants, this implies reducing bacteria settlement near the prosthesis and increasing roughness to improve implant-bone interaction and thus osseointegration. For other types of implants like bone fracture fixtures and cardiac pacemakers, reduced infection and adhesion (scar tissue) are highly desirable. Ultrafast laser is a powerful tool for modifying medical implant surfaces, at the micro- and/or nano-scale, towards improving or limiting their cell adhesions.
Biological complications related to bacterial engraftment on rough titanium are an issue in design of new functionalized implants. By fine-tuning femtosecond lasers (FSL) parameters, we aim to design multiscale (micro- + nano-scale) textured surfaces maintaining osteo-integration with unique antibacterial properties.
Titanium samples (Ti6-Al4V) are irradiated at 1030-515-257 nm wavelengths to produce various types of Laser-Induced Periodic Surface Structures (LIPSS). We revealed that LIPSS periodicity and morphology (linear or radial) are determinant for anti-bacterial properties. Preliminary results on multiscale surfaces reveal that cell adhesion of bone stem cells is maintained. FSL appears then as an innovative tool to produce dual-functionalized surfaces.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.