**2. Laser‐assisted strategies for renewable resources with medical applications**

In this section, we present the current strategy in laser‐assisted synthesis (emphasizing the challenges and limitations) and the potential biomedical applications of deposited/obtained coatings. An up‐to‐date example of composites based on natural biopolymers for medical applications by means of laser‐assisted processing is given.

The development of bionanotechnology based on laser techniques holds out great promise of improvements in the quality of life, including new treatments for disease providing a high potential for the fabrication of antimicrobial coatings for orthopedic implants [39].

Several techniques for the synthesis of thin films based on renewable resources such as spin‐ coating [40], dip‐coating [41], spray‐coating [42], as well as laser methods, such as laser‐ induced forward transfer [43], matrix‐assisted pulsed laser evaporation (MAPLE) [44], Combinatorial‐MAPLE [45]; resonant infrared (RIR) MAPLE [46] and MAPLE direct write [47] are currently used.

In spite of the vast list reported in the literature of biomaterials deposited in form of thin films, each of the above‐mentioned methods have some limitations in terms of coating thickness, multilayer deposition, adherence, composition or crystallinity. **Table 3** summarizes the generally used biomaterials based on renewable resources and deposition methods along with specific advantages and drawbacks.


As well as chitosan, lignin (Lig) is a renewable and a natural polymer [30]. This complex, amorphous organic polymer consists in a natural matrix which binds the strong and stiff cellulose units together, generally in natural wood. Lignin has been studied due to its antiox‐ idant and antimicrobial properties, making it the perfect candidate for biomedical applica‐

In the study of X. Pan et al. [32], lignin prepared from hybrid poplar wood chips exhibited higher antioxidant activities based on 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) assay. In the same time, in Ref. [33], it is reported that Kraft lignin from wood sources in pulp industry can

Nada et al. [34] demonstrated the lignin antimicrobial activities toward some bacteria and

The lignin incorporation in composite biomaterials led to biofabrication of new compounds with enhanced bioactivity and osteoconductivity [35, 36]. An unaltered incorporation of lignin provides a composite with enhanced stability and improved interconnected structure, while

Renewable resources have therefore a functional role in providing easily available and often

In this section, we present the current strategy in laser‐assisted synthesis (emphasizing the challenges and limitations) and the potential biomedical applications of deposited/obtained coatings. An up‐to‐date example of composites based on natural biopolymers for medical

The development of bionanotechnology based on laser techniques holds out great promise of improvements in the quality of life, including new treatments for disease providing a high

Several techniques for the synthesis of thin films based on renewable resources such as spin‐ coating [40], dip‐coating [41], spray‐coating [42], as well as laser methods, such as laser‐ induced forward transfer [43], matrix‐assisted pulsed laser evaporation (MAPLE) [44], Combinatorial‐MAPLE [45]; resonant infrared (RIR) MAPLE [46] and MAPLE direct write [47]

In spite of the vast list reported in the literature of biomaterials deposited in form of thin films, each of the above‐mentioned methods have some limitations in terms of coating thickness, multilayer deposition, adherence, composition or crystallinity. **Table 3** summarizes the generally used biomaterials based on renewable resources and deposition methods along with

potential for the fabrication of antimicrobial coatings for orthopedic implants [39].

**2. Laser‐assisted strategies for renewable resources with medical**

protect the oxidation of corn oil, being as efficient as vitamin E.

increasing the coating cohesion, as showed in Refs [37, 38].

applications by means of laser‐assisted processing is given.

cheap biomaterials for biofabrication of new generation of implants.

fungi‐like Gram‐positive bacteria (Bacillus subtilis and Bacillus mycoids).

tions [31].

110 Composites from Renewable and Sustainable Materials

**applications**

are currently used.

specific advantages and drawbacks.

**Table 3.** Biomaterials from renewable resources, deposition methods, advantages and drawbacks.

Between all techniques, laser‐based technologies are exhibiting a lot of advantages, as: fabrication of a wide range of different biomaterials, controlled film thickness, good adhesion to substrate [55]. Furthermore, laser‐based technologies imply a low material consumption and ensure the stoichiometry preservation of the growing films [39].

Next, relevant data regarding the laser processing techniques used for fabrication of medical implants based on renewable materials are presented. Concretely, the discussion spans the MAPLE and C‐MAPLE techniques.

MAPLE technique proved to be a safe approach for transporting and depositing delicate, heat sensitive molecules. Recent comprehensive reviews on MAPLE deposition of organic, biolog‐ ical and nanoparticle thin films exemplified a large potential in medicine, biology, pharma‐ ceutics or drug delivery applications of thin coatings obtained by this method [56].

The MAPLE experimental setup is presented in **Figure 1**.

**Figure 1.** MAPLE experimental setup.

MAPLE target consists of starting material (<10 wt.%) dissolved or suspended into a laser wavelength absorbing solvent when in frozen state. The biomaterial molecules achieve enough kinetic energy by collective collisions with the evaporating solvent molecules, guarantying a controlled transfer on the substrate while being efficiently pumped away by the vacuum system.

By most favorably adjusting the MAPLE deposition parameters (e.g., laser wavelength, laser fluence, repetition rate, solvent type, solute concentration, substrate temperature, background gas nature and pressure), the process can be performed without considerable biomaterial decomposition [38, 57].

Concomitantly, remarkable efforts were recently focused on the development of combinatorial processes for biofabrication of new biomaterials with innovative properties. Typically, the fabrication of a composite layer is carried out by premixing of biopolymer solutions followed by heating of coating [58] or film casting/solvent evaporation [59]. The combinatorial technol‐ ogy for the blending of two different biomaterials [45, 60–62] is based on MAPLE process (**Figure 2**).

**Figure 2.** Target holder in the case of MAPLE (left) and combinatorial‐MAPLE (right) techniques.

This brand new developed technique—Combinatorial‐MAPLE—stands for a simple, single step, biofabrication path which can easily limit the time of manipulation and biomaterials consumption [55].

In C‐MAPLE experiments, the two targets (e.g., Biomaterial 1 and Biomaterial 2) were concurrently evaporated by the laser beam, which was divided into two beams (**Figure 3**) by an optical splitter. The two beams were focused in parallel onto the surface of each target, containing the frozen solutions to be irradiated. A gradient of composition from 100% Biomaterial 1 to 100% Biomaterial 2 is thus obtained on a substrate, as schematically repre‐ sented in **Figure 4**.

**Figure 3.** Combinatorial‐MAPLE experimental setup.

**Figure 1.** MAPLE experimental setup.

112 Composites from Renewable and Sustainable Materials

decomposition [38, 57].

system.

(**Figure 2**).

MAPLE target consists of starting material (<10 wt.%) dissolved or suspended into a laser wavelength absorbing solvent when in frozen state. The biomaterial molecules achieve enough kinetic energy by collective collisions with the evaporating solvent molecules, guarantying a controlled transfer on the substrate while being efficiently pumped away by the vacuum

By most favorably adjusting the MAPLE deposition parameters (e.g., laser wavelength, laser fluence, repetition rate, solvent type, solute concentration, substrate temperature, background gas nature and pressure), the process can be performed without considerable biomaterial

Concomitantly, remarkable efforts were recently focused on the development of combinatorial processes for biofabrication of new biomaterials with innovative properties. Typically, the fabrication of a composite layer is carried out by premixing of biopolymer solutions followed by heating of coating [58] or film casting/solvent evaporation [59]. The combinatorial technol‐ ogy for the blending of two different biomaterials [45, 60–62] is based on MAPLE process

**Figure 2.** Target holder in the case of MAPLE (left) and combinatorial‐MAPLE (right) techniques.

**Figure 4.** Schematic representation of the thin film gradient structure growth and components intermixing developed by C‐MAPLE.

C‐MAPLE technique offers the possibility to combine and immobilize two or more biomate‐ rials, dissolved in different solvents, using diverse wavelengths. Next, by physical, chemical and biological characterization of the obtained structures, one may select the best compositions that can be synthesized from the two biomaterials.

MAPLE and C‐MAPLE techniques could unlock the research frontiers in biofabrication of composite based on renewable resources with great potential for various applications.
