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This study focuses on the fabrication and analysis of 3D-printed high-detail resolution cellulose acetate (CA) structures, particularly examining their specific surface area per volume (S_v). While electrospinning is a widely used technique for creating nanofiber membranes with high S_v, which is advantageous for applications like chromatography, the performance could be further improved by precisely controlling fiber placement. To further develop membranes, this research explores the use of electroprinting with small distances between nozzle and collector, here named near-collector electroprinting, to create 3D structures. By optimizing printing parameters, in particular the reduction of the nozzle-to-collector distance, 3D structures with precise fiber placement within a few micrometers were fabricated. The specific surface area per volume was calculated for both 3D-printed and electrospun filters. Results showed that 3D-printed structures with a 5 μm pitch achieved a S_v similar to electrospun filters.

Incorporating polyethyleneimine (PEI) in the CA ink enabled the 3D-printed structures to gain ion binding capacity which was further investigated. This ion-exchange ability which integrated into the printing step, eliminating the need for a separate post-modification process in bio-separation applications. By switching the substrate voltage from positive to negative, relative to the grounded nozzle, the printed fiber diameter decreased substantially for the CA ink with PEI. The S_v for near-collector electroprinted fibers of this material could therefore potentially be higher than that of electrospun membranes, provided that an order of magnitude higher printing speed, than presently possible can be used. These findings suggest that near-collector electroprinted CA structures offer potential improvements in membrane design and performance, making them a promising alternative to traditional electrospun membranes for bio-separation applications.

Selective Laser Sintering (SLS) is an emerging additive manufacturing technology with potential for the production of personalized pharmaceuticals. In this study, we investigated a novel simplified formulation approach in SLS-based manufacturing of individually dosed, multi-layered tablets with distinct layers of pure active pharmaceutical ingredient (API) and excipient. Indomethacin (IND) was chosen as the model API, and polyvinyl alcohol (PVA) served as the excipient. Unlike conventional methods requiring powder blending, this approach utilizes separate powder tanks for IND and PVA, enabling direct printing of alternating layers in a single-step procedure. We successfully fabricated tablets with controlled IND doses by varying the number of IND layers, maintaining consistent printing parameters across different compositions and confirming the API’s chemical stability in the product. Since SLS is conventionally used for thermoplastic substances, the successful sintering of pure IND layers was a key achievement in the study, as this crystalline API is typically not printable separately. Energy dispersive X-ray spectroscopy (EDS) demonstrated the successful formation of distinct API and excipient layers. Differential scanning calorimetry (DSC) characterization revealed that the sintering process partially amorphized IND, which may enhance dissolution and bioavailability. Dissolution testing indicated that the printed tablets exhibited improved dissolution rates compared to raw IND powder. The study successfully demonstrated the possibility of SLS-based production for personalized dosing by omitting powder blending steps. The ability to create individualized dosages with minimal excipients and simplified processing represents a step toward further investigation of SLS for clinical settings, including hospital and pharmacy-based drug production.

Lignin is an aromatic biomacromolecule with many promising properties that can be beneficial to polymer blends. The main objective of this work was to investigate the processability, compatibility, and recyclability of lignin blends with poly(lactic acid). Two different commercial kraft lignins and a phenolated organosolv lignin were blended with poly(lactic acid) at various weight percentages, targeting high lignin content (30, 50, and 70 wt %). Obtained blends were used in additive manufacturing via fused deposition modeling. All obtained materials were thoroughly characterized by tensile tests, thermogravimetric analysis, differential scanning calorimetry, and 31P NMR. The recyclability of the polymer blend materials was evaluated by re-extruding them up to four times, and their printability was also assessed. The results showed that the material retained its mechanical properties relatively well for up to three cycles after which its tensile strength decreased by 30%. Phenolated organosolv lignin exhibited better printability across a broader range of lignin content compared to kraft lignin analogs while maintaining similar thermal and mechanical properties.

Selective Laser Sintering (SLS) has the potential to offer a more accurate alternative to current-practice manipulation of oral dosage forms for pediatric, geriatric, and dysphagia-suffering patient groups. In order to create the best possible dosage forms for these patient groups, an in-depth look into how a dosage forms geometry impacts the overall properties is essential. In this study, the impact of geometry on SLS manufactured oral dosage forms on the tablet’s microstructure, actual-to-theoretical volume, mass deviation, disintegration, and dissolution was investigated. Three different shapes; cylinder, hollow cylinder, and conical frustum with similar surface area (SA), as well as three cylinders with different diameters, were investigated. The results indicate that the geometry has an impact on the mass uniformity, resultant volume, disintegration, and dissolution properties of the tablets. The mass uniformity analysis of the tablets provided the most variation between tablets of different sizes, with more uniformity for tablets with similar SA-to-volume ratio (SA/V). When examining the actual-to-theoretical volume of the tablets, a greater variance between the actual and theoretical volumes for shapes with higher overall SA was observed. The values found are approximately 1.05 for the three differently sized cylinders, 1.23 for the conical frustum, and 1.44 for the hollow cylinder, following this trend. Disintegration data supported a link between SA/V and average disintegration time, observed with the tablet of the highest SA/V disintegrating in 12 s and the tablet with the lowest SA/V disintegrating in 58 s. Dissolution results also indicated a strong dependence on SA/V. Hence, when novel ways to produce oral dosage form tablets become available by additive manufacturing, such as SLS, both geometry and SA/V must be taken into consideration in the tablet design process to ensure appropriate release kinetics and dosing standards.

Electrospinning is a technique used to fabricate polymer fibers in micro- and nanoscales. Due to the large distance between the nozzle and collector, there is a limited positioning accuracy of electrospun fibers. To enhance the possibility of fabricating structures with micrometer placement, an electroprinting technique has been developed. By reducing the distance between the nozzle and the collector it is demonstrated that it is possible to get an improved control over fiber positioning which gives a possibility to fabricate designed 3D structures at the micron scale. In this study, cellulose acetate (CA) has been selected as a biomaterial to advance the 3D printing of membranes with possible use in separation applications. Various parameters, such as CA concentration and molecular weight, printing speed, printing pattern, applied voltage, etc. are evaluated with respect to printing control. Results indicate that by optimizing the printing parameters it is possible to print structures with inter- fiber distances down to 3 mu m and fiber diameters at a sub-mu m scale. This electroprinting development is promising for the fabrication of customized separation membranes. However, printing speed still remains a challenge.

A wide array of carbon materials finds extensive utility across various industrial applications today. Nonetheless, the production processes for these materials continue to entail elevated temperatures, necessitate the use of inert atmospheres, and often involve the handling of aggressive and toxic chemicals. The prevalent method for large-scale carbon material production, namely the pyrolysis of waste biomass and polymers, typically unfolds within the temperature range of 500–700 °C under a nitrogen (N2) atmosphere. Unfortunately, this approach suffers from significant energy inefficiency due to substantial heat loss over extended processing durations. In this work, we propose an interesting alternative: the carbonization of photothermal nanocellulose/polypyrrole composite films through CO2 laser irradiation in the presence of air. This innovative technique offers a swift and energy-efficient means of preparing carbon materials. The unique interaction between nanocellulose and polypyrrole imparts the film with sufficient stability to retain its structural integrity post-carbonization. This breakthrough opens up new avenues for producing binder-free electrodes using a rapid and straightforward approach. Furthermore, the irradiated film demonstrates specific and areal capacitances of 159 F g−1 and 62 μF cm−2, respectively, when immersed in a 2 M NaOH electrolyte. These values significantly surpass those achieved by current commercial activated carbons. Together, these attributes render CO2-laser carbonization an environmentally sustainable and ecologically friendly method for carbon material production.

Pharmacies are currently unable to stock proper oral dosage forms for pediatric populations. This leads to manipulation of medications or the need to compound specialized medications, which can be a time-consuming process. Using Semisolid Extrusion (SSE) additive manufacturing (AM), specialized medications can be produced in an expedited process from off-the shelf medication in a hospital or outpatient pharmacy setting. In this study, tablets with a desired dose of 5 mg of metoprolol tartrate derived from commercial Seloken™ 50 mg tablets were 3D printed in a hospital setting. Validation testing was done on five batches, highlighting tablets with a high uniformity in mass and dimension, drug content, acceptable microbial assays, and prolonged release during in-vitro analysis. The average drug content found for the tablets was within ±6% of 5 mg for all batches produced. Comparisons were done between the SSE tablets and capsules produced in an external compounding facility, highlighting several positive aspects of SSE-produced tablets beyond simply shortening the production timeline. The SSE tablets printed in this study are characterized by their smaller size, enhanced prolonged release properties, and more uniform drug content across the tested samples. Additionally, interviews with pharmaceutical professionals were conducted to determine the positive aspects of SSE and further improvements to bring this technique as seamlessly as possible into the pharmacy. This study underscores the feasibility of employing SSE in the production of specialized medications within a hospital environment. Furthermore, it highlights the methodological advantages SSE offers over existing production standards, demonstrating its potential to improve pharmaceutical manufacturing in healthcare settings.