Biomaterials, defined by high biocompatibility and biodegradability, are intensively used in medical applications, mainly to replace partial or total, damaged or destroyed hard or soft tissues. Most of them are used not only as coatings for implant coverage but also as parts for some medical devices. In the last decades, researchers sought to find the optimum processing methods and parameters to modify or deposit the biomaterial of interest. An important family of techniques, used to process a biomaterial, is represented by laser techniques, based upon laser ablation phenomenon. Laser ablation of biomaterials ensures the transference or modification with good precision and without or with minimal disruptions generated. To obtain thin coatings from biomaterials, one can use deposition techniques: pulsed laser deposition (PLD) or matrix-assisted pulsed laser evaporation (MAPLE). These techniques are chosen according to the selected biomaterial and desired performances of the obtained coating. Therefore, some sensitive biomaterials can be transferred only by MAPLE. Some results in the field of calcium phosphates deposited by PLD or MAPLE are presented, proving the usefulness of these biomaterials for medical applications.
Part of the book: Applications of Laser Ablation
This chapter reviews the laser ablation of delicate organic/biological substances by matrix-assisted pulsed laser evaporation (MAPLE). It is shown that direct ablation in this case is possible but sometimes not workable at all in adverse conditions. The considered solution is the protection by a prevalent dissolving/suspending component that can allow for a “shielded” ablation by the frozen solvent followed by its gradual evaporation by melting, evaporation and evacuation by pumping system. We extend the study to the case of non-UV absorbing solvents, e.g., water, when the primary interaction between laser and solute ignites evaporation process at a lower ablation threshold due to reduced pressure inside irradiation chamber. We called this case as “generalized” MAPLE interaction. Relevant examples are provided and critically analyzed in view of potential applications for nanobiomedicine, biosensors, advanced implants and chemical technologies.
Part of the book: Laser Ablation
An effective way of decontamination using optical metamaterials like photonic crystals consisting of glass microspheres or granulated quartz with various geometries is proposed. The efficient decontamination using the evanescent zone of metamaterials opens a new perspective in pathogen decontamination. We propose different topological structures of metamaterials to enlarge the contact surface of ultraviolet radiation with polluted translucent fluids. The approach is based upon the increased transfer of UV radiation via evanescent waves of metamaterials into contaminated translucent fluids. A series of experimental estimations of the decontamination rate of this type of metamaterials have been made. For these investigations, a decontamination core filled up with metamaterials is used through which the contaminated fluid freely flows. Experiments have conclusively proved that evanescent zone of quartz and optical fiber metamaterials can effectively inactivate Coliform (including Escherichia coli), or Enterococcus bacteria, as well as yeast and Kombucha cultures.
Part of the book: Advanced Surface Engineering Research