Multifunctional Material Extrusion 3D-Printed Antibacterial Polylactic Acid (PLA) with Binary Inclusions: The Effect of Cuprous Oxide and Cellulose Nanofibers

Abstract

In this work, we present an effective process easily adapted in industrial environments for the development of multifunctional nanocomposites for material extrusion (MEX) 3D printing (3DP). The literature is still very limited in this field, although the interest in such materials is constantly increasing. Nanocomposites with binary inclusions were prepared and investigated in this study. Polylactic acid (PLA) was used as the matrix material, and cuprous oxide (Cu2O) and cellulose nanofibers (CNF) were used as nanoadditives introduced in the matrix material to enhance the mechanical properties and induce antibacterial performance. Specimens were built according to international standards with a thermomechanical process. Tensile, flexural, impact, and microhardness tests were conducted. The effect on the thermal properties of the matrix material was investigated through thermogravimetric analysis, and Raman spectroscopic analysis was conducted. The morphological characteristics were evaluated with atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDS) analyses. The antibacterial performance of the prepared nanomaterials was studied against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria, with a screening agar well diffusion method. All nanocomposites prepared exhibited biocidal properties against the bacteria tested. The tested PLA/1.0 CNF/0.5 Cu2O material had 51.1% higher tensile strength and 35.9% higher flexural strength than the pure PLA material.

Trilateral Multi-Functional Polyamide 12 Nanocomposites with Binary Inclusions for Medical Grade Material Extrusion 3D Printing: The Effect of Titanium Nitride in Mechanical Reinforcement and Copper/Cuprous Oxide as Antibacterial Agents

“…Nanocomposites using polycarbonate (PC) as a matrix material and TiN in MEX 3DP show a similar enhancement effect, by the addition of the TiN filler in the PC matrix material [ 56 ]. Additionally, nanomaterials with binary inclusions for MEX 3DP, using Polylactic Acid (PLA) as the matrix material and Cu 2 O as one of the two fillers, also had a similar trend to the results of this study [ 35 ]. Regarding the antibacterial performance of the developed nanocomposites featuring the antibacterial additives (Cu and Cu 2 O), all the nanocomposites developed had biocidal properties at least for the two bacteria tested, i.e., gram-negative E. coli and gram-positive S. aureus .…”

“…As a result, nanocomposites for 3DP and AM, in general, have been developed and characterized with improved mechanical, electrical, and thermal properties [ 20 , 33 , 34 ]. At the same time, properties such as antibacterial response have been introduced in biocompatible and medical grade materials, making them suitable for different healthcare and medical applications [ 4 , 5 , 8 , 35 ].…”

“…For the development of composites and nanocomposites with antibacterial properties, additives with such properties are introduced into the materials, with copper (Cu) and its oxides, such as copper (I) oxide (cuprous oxide, Cu 2 O), frequently used in the literature [ 8 , 32 , 34 , 35 ]. Cu in different types (nanopowder and others) has been widely used and investigated in the literature for various types of applications [ 59 , 60 , 61 , 62 ].…”

“…Cuprous oxide has been employed in semiconductors [ 67 , 68 ], among other applications; still, it is mainly used and investigated for its antibacterial properties [ 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 ]. Its antibacterial properties have also been exploited in vat photopolymerization [ 32 , 34 ] and MEX 3DP for polylactic acid (PLA) [ 35 ] and PA12 polymers [ 8 ], achieving sufficient antibacterial performance in the nanocomposites developed in these studies. Copper and other metal nanoparticles (NPs) biocidal properties are achieved, since they have physicochemical characteristics, imitating the host defense peptide (HDP), which is the main mechanism in living organisms for killing or inhibiting bacteria [ 77 , 78 ].…”

Multifunctional Medical Grade Resin with Enhanced Mechanical and Antibacterial Properties: The Effect of Copper Nano-Inclusions in Vat Polymerization (VPP) Additive Manufacturing

“…In AM it has been used in powder-based 3D printing processes to build parts [ 72 , 73 , 87 , 88 ], in electron beam melting AM [ 89 ], and in ultrasonic AM [ 90 ]. In nanoparticle form, Cu has been used to induce antibacterial properties in polymers used as matrix materials in vat photopolymerization [ 44 , 91 ] and in material extrusion (MEX) 3D printing [ 92 , 93 ]. The introduction of antibacterial properties in polymeric materials in different AM processes has gained interest in the research, due to the potential of such composites in medical and food applications.…”