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A Review of 3D Printing Technology for Rapid Medical Diagnostic Tools Abstract Early diagnosis of diseases leads to selecting the appropriate treatment method and prevention of problems, such as drug resistance. It also prevents the spread of diseases and pandemics in some cases and plays a crucial role in treating diseases. In some diseases, such as bacterial infections, effective diagnoses prevent antibiotics overuse and make such antibiotics treatment futile against infections. Additive manufacturing (AM) or 3D printing has received great attention in recent years and has been applied in a wide variety of biomedical applications, such as implants and diagnostic tools. The structures fabricated via this method are highly precise, economical and can have complex geometries, such as interconnecting channels, undercuts, and curvatures. Developing sensor and sensor array in a shorter time with high sensitivity is possible by applying AM fabrication approach. Other fields such as dentistry also take advantage of 3D printing technology to ease the diagnosis process as it helps to fabricate complex structures with dimensions close to reality which cannot be achieved by any other method. In this review, recent advances in AM fabrication method in producing rapid diagnosis tools have been discussed by providing a classification of advanced diagnostic tools using AM.

Multi-walled carbon nanotubes (MWCNTs) are one of the preferred candidates for reinforcing polymeric nanobiocomposites, such as acrylic bone type of cement. In this study, at first, bulk samples of the reinforced polymethylmethacrylate (PMMA) matrix were prepared with 0.1, 0.25, and 0.5 wt per wt% of MWCNTs by the casting method. Tensile and three-point bending tests were performed to determine the essential mechanical properties of bone cement, such as tensile and bending strengths. The tensile fracture surfaces were investigated by scanning electron microscopy (SEM). The commercial software (Abaqus) was used to conduct finite element analysis (FEA) by constructing a representative volume element (RVE) model for numerically computing the tensile and bending parameters of PMMA-MWCNT nanocomposites. Finally, MTT assays were utilized to evaluate the cell viability on the surface of nanobiocomposites. The results show that by increasing the MWCNT amount in the PMMA-based cement, the bending strengths (BS), tensile strength (TS), and elastic modulus (EM) increased considerably. Furthermore, the disparity between the FEA and experimental TS, EM, and BS values was less than 20%. According to MTT viability experiments, adding MWCNTs to PMMA had no influence on PMMA toxicity and resulted in a negative response to interaction with mesenchymal stem cells. The cell density on the nanobiocomposite was more than pristine-PMMA.

In this study, colloidal gold nanoparticles (NPs) with sizes less than 20 nm were added to the dentin adhesive in various concentrations to achieve favorable antibacterial properties. The effect of gold NPs on mechanical, antibacterial, and cytotoxicity features of adhesive was evaluated systematically. It was shown that the addition of gold NPs at the concentration of 5X (i) increased flexural strength of dentin tooth adhesive by 75%, (ii) increased the micro-shear bond strength by 60%, and (iii) increased the tensile diameter strength of adhesive by 65% compared to the based adhesive. Multiscale modeling was used to simulate and calculate stress and strain distribution around the nanoparticles and within the adhesive matrix. Antibacterial properties of adhesives containing gold NPs were examined using disk diffusion and the pour plate methods. The results showed that adhesive with the 5X concentration of gold NPs had a bacterial growth inhibition zone with a diameter of 2 mm is in the disk diffusion method which indicates the antibacterial characteristics of adhesive at this concentration. Also, the antibacterial effect of adhesive-containing NPs was observed in the pour plate method and the reduction of bacterial growth is increased by the addition of nanoparticles. The cytotoxicity of NPs is examined in pure form and com-bination with dental adhesive using the MTT assay. The results showed that pure gold NPs have shown no toxicity for the growth of cells and the incorporation of gold NPs has increased the cell viability in the base adhesive.

Early diagnosis of diseases leads to selecting the appropriate treatment method and prevention of problems, such as drug resistance. It also prevents the spread of diseases and pandemics in some cases and plays a crucial role in treating diseases. In some diseases, such as bacterial infections, effective diagnoses prevent antibiotics overuse and make such antibiotics treatment futile against infections. Additive manufacturing (AM) or 3D printing has received great attention in recent years and has been applied in a wide variety of biomedical applications, such as implants and diagnostic tools. The structures fabricated via this method are highly precise, economical and can have complex geometries, such as interconnecting channels, undercuts, and curvatures. Developing sensor and sensor array in a shorter time with high sensitivity is possible by applying AM fabrication approach. Other fields such as dentistry also take advantage of 3D printing technology to ease the diagnosis process as it helps to fabricate complex structures with dimensions close to reality which cannot be achieved by any other method. In this review, recent advances in AM fabrication method in producing rapid diagnosis tools have been discussed by providing a classification of advanced diagnostic tools using AM.

In this study, colloidal gold nanoparticles (NPs) with sizes less than 20 nm were added to the dentin adhesive in various concentrations to achieve favorable antibacterial properties. The effect of gold NPs on mechanical, antibacterial, and cytotoxicity features of adhesive was evaluated systematically. It was shown that the addition of gold NPs at the concentration of 5X (i) increased flexural strength of dentin tooth adhesive by 75%, (ii) increased the micro-shear bond strength by 60%, and (iii) increased the tensile diameter strength of adhesive by 65% compared to the based adhesive. Multiscale modeling was used to simulate and calculate stress and strain distribution around the nanoparticles and within the adhesive matrix. Antibacterial properties of adhesives containing gold NPs were examined using disk diffusion and the pour plate methods. The results showed that adhesive with the 5X concentration of gold NPs had a bacterial growth inhibition zone with a diameter of 2 mm is in the disk diffusion method which indicates the antibacterial characteristics of adhesive at this concentration. Also, the antibacterial effect of adhesive-containing NPs was observed in the pour plate method and the reduction of bacterial growth is increased by the addition of nanoparticles. The cytotoxicity of NPs is examined in pure form and com-bination with dental adhesive using the MTT assay. The results showed that pure gold NPs have shown no toxicity for the growth of cells and the incorporation of gold NPs has increased the cell viability in the base adhesive.

A biomaterials approach to Schwann cell development in neural tissue engineering

Characterization and multiscale modeling of novel calcium phosphate composites containing hydroxyapatite whiskers and gelatin microspheres