High-Power Laser Deposition of Chitosan Polymers: Medical and Environmental Applications

Abstract

High-power laser irradiation interaction with natural polymers in biocomposites and Laser-Induced Chitin Deacetylation (LICD) was studied in this work, in order to produce thin films consisting of chitosan composite. The new method can lead to a cutting-edge technology, as a response to the concern regarding the accumulation of “natural biological waste” and its use. The process consists of high-power laser irradiation applied on oyster shells as the target and deposition of the ablated material on different substrates. The obtained thin films we analyzed by FTIR, UV-VIS and LIF spectroscopy, as well as SEM-EDS and AFM. All the results indicated that chitin was extracted from the shell composite material and converted to chitosan by deacetylation. It was, thus, evidenced that chemical transformation in the chitin polymer side-chain occurs during laser irradiation of the oyster shell and in the resulted plasma plume of ablation. The numerical simulation in COMSOL performed for this study anticipates and confirms the experimental results of chitin deacetylation, also providing information about the conditions required for the physico-chemical processes involved. The high sorption properties of the thin films obtained by a LICD procedure is evidenced in the study. This quality suggests that they should be used in transdermal patch construction due to the known hemostatic and antibacterial effects of chitosan. The resulting composite materials, consisting of the chitosan thin films deposited on hemp fabric, are also suitable for micro-filters in water decontamination or in other filtering processes.

Nano-Biocomposite Materials Obtained from Laser Ablation of Hemp Stalks for Medical Applications and Potential Component in New Solar Cells

“…The droplets’ widths were 4.78 μm and 2.610 μm, respectively, while the droplets’ heights were 357 nm and 98 nm. The topographic lines ( Figure 3 b,e,h,k) also indicate overlapping or clumped droplets by the jagged appearance of the lines [ 21 ], this indicates that most of the micrometric structures are in fact the result of nanostructure aggregation. The roughness is well observed in the 3D plots ( Figure 3 c,f,i,l).…”

“…The diagrams in Figure 6 are 2D plots resulting from the simulation in COMSOL and show the temperature evolution during laser irradiation over time. The influences of heat diffusion between the composite lignin/Ca components are observed in Figure 6 d–f where the maximum temperatures are shifted from the center of the spot (the center of the spot is at 25.4 mm in the diagrams) and where the maximum heating is obtained, which is usually when simulating the laser heating of homogeneous materials [ 21 , 31 , 32 , 33 ].…”

“…For LIF spectroscopy performed on the thin films PLD-HMP-STK/Glass and PLD-HMP-STK/HMP-FB, an excitation laser beam of 355 nm was used, and the installation is presented in Figure 8 . The characteristic fluorescence peak of the thin film PLD-HMP-STK/HMP-FB is noticed at 508 nm, as well as a number of secondary peaks due to chemical reactions [ 21 , 27 , 29 ] and to laser interactions with different constituents of the thin film, such as p -coumaric acid emitting at 430 nm and 455 nm [ 35 , 36 ] and ferulic acid with emissions noticed at 480 nm and 498 nm [ 37 , 38 ], as seen in the spectrum of Figure 9 and Table 3 . In the LIF spectrum of PLD-HMP-STK/Glass ( Figure 9 and Table 3 ), peaks of coumaric and ferulic acids are noticed at 424 nm, 443 nm, 452 nm, 482 nm and 498 nm, respectively, while peaks at 603 nm and 627 nm are assigned to chlorophyll [ 35 , 37 , 38 ].…”

“…The pressure in the deposition chamber was of 10 −2 Torr, the distance between the target to the support for thin film deposition was of 30 mm, and the deposition was 30 min long. The parameters and conditions for the PLD process were chosen in order to preserve most of the polymer chemical structure [ 21 , 27 , 29 ]. Additionally, the numerical simulation completed the information regarding plasma threshold conditions and for adjustments regarding the PLD procedure.…”

A Review on Antibacterial Biomaterials in Biomedical Applications: From Materials Perspective to Bioinks Design

“…Hence, encapsulating antibacterial agents into the biomaterial matrix has attained much consideration in the past few years [ 147 ]. Antibacterial biomaterials are comparatively capable of repelling bacterial cells, inhibiting their adhesion, or inactivating/destroying cells attached to the surface, while not sufficiently productive in destroying the pathogens due to the complicated mechanisms of bacteria [ 148 , 149 , 150 , 151 , 152 , 153 , 154 , 155 , 156 , 157 , 158 , 159 , 160 , 161 , 162 , 163 , 164 , 165 , 166 , 167 , 168 , 169 , 170 , 171 , 172 ]. Thus, developing highly effective and specifically targeted biomaterials that generate antimicrobial agents and their service in 3D printing inks is vital for TE applications.…”