An Overview on Personal Protective Equipment (PPE) Fabricated with Additive Manufacturing Technologies in the Era of COVID-19 Pandemic

Validation of 3D printed MAYO tubes and stethoscope in simulated medical environment - Tools fabricated with additive manufacturing for emergency care

Emergency and disaster medical care often face resource or equipment shortages. 3D printing technology has been proven to be effective in cases with insufficient supply chains. MAYO tubes and stethoscopes are essential components of ABCDE patient examinations; however, 3D-printed variants have not been fully tested. These 3D-printed instruments were substituted and validated in a simulated pre-hospital environment. In total, 26 participants were included in this study. Fifteen clinicians or paramedics with at least 3 years of professional experience and 10 medical students. One student was excluded because he had relevant experience with emergency care. As basic tasks, the placement of MAYO tubes and auscultation with stethoscopes were performed using medical simulators. 3D printed instruments were compared with conventional clinical devices by measuring the time required for the intervention, success rate, and user satisfaction. In the study FFF (Fused Filament Fabrication (FFF), SLS (Selective Laser Sintering (SLS), and SLA (stereolithography) 3D printing were used in this study. The times required for implementation and auscultation were examined for each instrument. There was no significant difference between the MAYO tube (p = 0.798) and the stethoscope (p = 0.676). In the case of stethoscopy, the study investigated the correct diagnosis, and no significant difference was found (p = 0.239), although an interesting trend was observed. Regarding the MAYO tube, the study found no significant difference in correct position formation (p = 0.163). The experience levels of the groups did not influence these factors. However, significant differences in user satisfaction were found in both cases in favour of the conventional versions (p < 0.001). Overall, the results of this study suggest that 3D-printed devices could be suitable replacements for clinic-based devices in emergency situations. The 3D-printed devices did not perform inferiorly at any of the indicated points compared to their classical counterparts. However, the practical applicability of the devices used in this study requires further investigation.

Multicomponent Acrylic Formulation Design for Corrosion Casting with Controlled Mechanical Properties

Corrosion casting based on the curing of acrylic resins enables one to create casts as replicas of body systems, enhancing our knowledge of veterinary medicine. The identification of the optimal chemical formulations as well as the processing conditions, the delivery of good control during the liquid state and the excellent macroscopic properties during solidification and after use are remaining challenges. In the present work, based on the identification of more qualitative trends, it is demonstrated that multicomponent comonomer mixtures are interesting materials that can be used to expand the range of mechanical properties and can specifically result in a better balance between stiffness and flexibility while guaranteeing dimensional stability. Emphasis is put on a large pool of formulations in the testing phase to then perform a detailed mechanical flexural analysis for the most promising cases during a more rigorous testing phase, accounting for a new pragmatic protocol for the pot life. This protocol consists of a vial-based turning test and a measurement of the viscosity variation up to 1000 mPa∙s and highlights the complex interplay between the overall initial concentrations and the impact of the absence of mixing once the system is at rest. It is demonstrated that the use of only low-molar-mass crosslinkers should be avoided, and overall, an intermediate amount of crosslinkers is recommendable.

Biomedical waste plastic: bacteria, disinfection and recycling technologies-a comprehensive review

Plastic recycling reduces the wastage of potentially useful materials as well as the consumption of virgin materials, thereby lowering the energy consumption, air pollution by incineration, soil and water pollution by landfilling. Plastics used in the biomedical sector have played a significant role. Reducing the transmission of the virus while protecting the human life in particular the frontline workers. Enormous volumes of plastics in biomedical waste have been observed during the outbreak of the pandemic COVID-19. This has resulted from the extensive use of personal protective equipment such as masks, gloves, face shields, bottles, sanitizers, gowns, and other medical plastics which has created challenges to the existing waste management system in the developing countries. The current review focuses on the biomedical waste and its classification, disinfection, and recycling technology of different types of plastics waste generated in the sector and their corresponding approaches toward end-of-life option and value addition. This review provides a broader overview of the process to reduce the volume of plastics from biomedical waste directly entering the landfill while providing a knowledge step toward the conversion of "waste" to "wealth." An average of 25% of the recyclable plastics are present in biomedical waste. All the processes discussed in this article accounts for cleaner techniques and a sustainable approach to the treatment of biomedical waste.

Graphical abstract

Special Issue Editorial: Applications of 3D Printing for Polymers

Polymer 3D printing is an emerging technology highly relevant in diverse industries, including medicine, electronics, and robotics [...]

Coronavirus disease 2019: Repeated immersion of chlorine-containing disinfectants has adverse effects on goggles

Introduction

During COVID-19, some front-line personnel experienced varying degrees of eye discomfort due to the use of goggles repeatedly disinfected with chlorine-containing disinfectant.

Methods

The eye damage information of 276 front-line personnel who used goggles in a hospital from October 1, 2021, to December 1, 2021, was collected by filling out a questionnaire. To study the effect of chlorinated disinfectants on goggles, we immersed the goggles in the same volume of water and chlorinated disinfectant buckets. We tested the light transmittance, color and texture, and airtightness of the goggles at different times (1, 3, 12, 24, 36, 48, 60, 72, 96, 120, 144, 168, 192, 216, 240, and 268 h). In addition, we detected where chlorinated disinfectant remained in the goggles by using disinfectant concentration test paper.

Results

60 (21.82%) people experienced dry eyes, stinging pain, photophobia and tearing, conjunctival congestion, eyelid redness, and swelling. After treatment or rest, the patient's ocular symptoms were significantly relieved within 3 days. With the extension of disinfection time, the light transmission of the lenses gradually decreased, and the light transmission reduced when immersion occurred at 216 h. After 72 h of disinfection, the color of the goggle frame began to change to light yellow, the texture gradually became hard and brittle, and the color became significantly darker at 268 h of disinfection. The airtightness of the goggles began to decrease after 168 h of disinfection, the airtightness decreased substantially at 268 h, and the shape changed significantly. In addition, the concentration test paper results show that the disinfection solution mainly resides in the goggle frame seam and goggles' elastic bands' bundle.

Conclusions

Repeated chlorine disinfectant disinfection will reduce the effectiveness of goggles protection and damage front-line personnel's eye health.

A Novel Hydrophilic, Antibacterial Chitosan-Based Coating Prepared by Ultrasonic Atomization Assisted LbL Assembly Technique

To explore the potential applicability of chitosan (CTS), we prepared aldehyde chitosan (CTS-CHO) with chitosan and sodium periodate via oxidation reaction and then a chitosan-based hydrophilic and antibacterial coating on the surface of poly (lactic acid) (PLA) film was developed and characterized. The oxidation degree was determined by Elemental analyser to be 12.53%, and a Fourier transform infrared spectroscopy was used to characterize the structure of CTS-CHO. It was evident that CTS-CHO is a biocompatible coating biomaterial with more than 80% cell viability obtained through the Live/Dead staining assay and the alamarBlue assay. The hydrophilic and antibacterial CTS-CHO coating on the PLA surface was prepared by ultrasonic atomization assisted LbL assembly technique due to Schiff's base reaction within and between layers. The CTS-CHO coating had better hydrophilicity and transparency, a more definite industrialization potential, and higher antibacterial activity at experimental concentrations than the CTS coating. All of the results demonstrated that the ultrasonic atomization-assisted LbL assembly CTS-CHO coating is a promising alternative for improving hydrophilicity and antibacterial activity on the PLA surface. The functional groups of CTS-CHO could react with active components with amino groups via dynamic Schiff's base reaction and provide the opportunity to create a drug releasing surface for biomedical applications.

Mechanics of 3D-Printed Polymer Lattices with Varied Design and Processing Strategies

Emerging polymer 3D-printing technologies are enabling the design and fabrication of mechanically efficient lattice structures with intricate microscale structures. During fabrication, manufacturing inconsistencies can affect mechanical efficiency, thereby driving a need to investigate how design and processing strategies influence outcomes. Here, mechanical testing is conducted for 3D-printed lattice structures while altering topology, relative density, and exposure time per layer using digital light processing (DLP). Experiments compared a Cube topology with 800 µm beams and Body-Centered Cube (BCC) topologies with 500 or 800 µm beams, all designed with 40% relative density. Cube lattices had the lowest mean measured relative density of ~42%, while the 500 µm BCC lattice had the highest relative density of ~55%. Elastic modulus, yield strength, and ultimate strength had a positive correlation with measured relative density when considering measurement distributions for thirty samples of each design. BCC lattices designed with 50%, 40%, and 30% relative densities were then fabricated with exposure-per-layer times of 1500 and 1750 ms. Increasing exposure time per layer resulted in higher scaling of mechanical properties to relative density compared to design alteration strategies. These results reveal how design and fabrication strategies affect mechanical performance of lattices suitable for diverse engineering applications.

Emerging technologies for combating pandemics

INTRODUCTION

Covid-19, alongside previous pandemics, has highlighted the need for the continued development of technologies that are at our disposal. Emerging technologies are those that show true promise in achieving such a goal and have begun to form sturdy independent research areas. Technological advances in healthcare must continually develop to ensure that the world is prepared for any future diseases that may ensue. As such, a strategic review into 39 manuscripts since 2019 has been conducted to determine the prominence of emerging technologies since the beginning of the Covid-19 pandemic.

AREAS COVERED

Relating to their use in a pandemic state, additive manufacturing (AM), biofabrication, microfluidics, biomedical microelectromechanical systems (BioMEMS), and artificial intelligence (AI) are described. Applications over the past 2-3 years, as well as future developments, are considered throughout.

EXPERT OPINION

All the technologies mentioned in this review are sure to develop further, having shown their importance and value during the covid-19 pandemic. As research continues within the area, their efficacy will increase to the point where it likely will become gold standard for pandemic control. Combining certain technologies mentioned has also proved to have had great success in improving the final results obtained.

Scientometric Review for Research Patterns on Additive Manufacturing of Lattice Structures

Over the past 15 years, interest in additive manufacturing (AM) on lattice structures has significantly increased in producing 3D/4D objects. The purpose of this study is to gain a thorough grasp of the research pattern and the condition of the field’s research today as well as identify obstacles towards future research. To accomplish the purpose, this work undertakes a scientometric analysis of the international research conducted on additive manufacturing for lattice structure materials published from 2002 to 2022. A total of 1290 journal articles from the Web of Science (WoS) database and 1766 journal articles from the Scopus database were found using a search system. This paper applied scientometric science, which is based on bibliometric analysis. The data were subjected to a scientometric study, which looked at the number of publications, authorship, regions by countries, keyword co-occurrence, literature coupling, and scientometric mapping. VOSviewer was used to establish research patterns, visualize maps, and identify transcendental issues. Thus, the quantitative determination of the primary research framework, papers, and themes of this research field was possible. In order to shed light on current developments in additive manufacturing for lattice structures, an extensive systematic study is provided. The scientometric analysis revealed a strong bias towards researching AM on lattice structures but little concentration on technologies that emerge from it. It also outlined its unmet research needs, which can benefit both the industry and academia. This review makes a prediction for the future, with contributions by educating researchers, manufacturers, and other experts on the current state of AM for lattice structures.

The Impact of COVID-19 on the Physical Well-being of Nursing and Medical Personnel: An Integrative Review

Objective: To highlight the impact of responding to COVID-19 on the physical well-being of nursing and medical personnel. Method: This integrative literature review includes Spanish, English, and Portuguese articles. From July 10 to 16, 2020, the search was carried out in the Cumulative Index to Nursing and Allied Health Literature, Latin American and Caribbean Health Sciences Literature, Web of Science, SciVerse Scopus, and National Library of Medicine databases. Twenty-five studies were analyzed, and the results are presented descriptively and in tables. Results: Of the total number of articles, 52 % addressed coronavirus infection and related factors as an impact on nursing and medical personnel’s physical well-being resulting from responding to COVID-19, 28 % addressed sleep quality and predictors, and 20 % addressed damage stemming from the use of personal protective equipment or other preventive measures. Conclusions: Responding to COVID-19 has been conducive to coronavirus infection among personnel due to the work process and prevention measures, poor sleep quality due to mental disorders and lack of social support, and physical harm, such as headaches and skin injuries, due to the use of protective equipment and hand disinfection.

Required parameters for modelling heterogeneous geographically dispersed manufacturing systems

COVID-19 and global crises/events are driving governments to rethink their national manufacturing strategies. The drastic change of societal conditions has exposed our reliance on a constrained set of production practices. Furthermore, the future manufacturing landscape indicates - supply chain crises, trade agreements and natural disasters - a high level of volatility which requires a response that is far from being achieved. While these emergent challenges have called the efficacy of established practices into question, new manufacturing technologies, such as Additive Manufacturing (AM), present the capability to provide a solution. One proposal is agent-based brokering of AM which could be a method for tackling local, regional, national, and international production needs. However, to achieve the reality of brokered AM, it is imperative that the diversity of AM capability is considered. Diversity that existing homogeneous modelling of AM and manufacturing systems rarely consider or capture. This paper conceptualizes the reality of AM systems and elucidates parameters that are necessary for successful modelling and subsequent co-ordination. Having presented the required parameters the paper continues to discuss requisite levels of abstraction, suitable performance metrics and the role of humans in agent-based manufacturing systems.

Supporting Technologies for COVID-19 Prevention: Systemized Review

Background

During COVID-19, clinical and health care demands have been on the rapid rise. Major challenges that have arisen during the pandemic have included a lack of testing kits, shortages of ventilators to treat severe cases of COVID-19, and insufficient accessibility to personal protective equipment for both hospitals and the public. New technologies have been developed by scientists, researchers, and companies in response to these demands.

Objective

The primary objective of this review is to compare different supporting technologies in the subjugation of the COVID-19 spread.

Methods

In this paper, 150 news articles and scientific reports on COVID-19–related innovations during 2020-2021 were checked, screened, and shortlisted to yield a total of 23 articles for review. The keywords “COVID-19 technology,” “COVID-19 invention,” and “COVID-19 equipment” were used in a Google search to generate related news articles and scientific reports. The search was performed on February 1, 2021. These were then categorized into three sections, which are personal protective equipment (PPE), testing methods, and medical treatments. Each study was analyzed for its engineering characteristics and potential social impact on the COVID-19 pandemic.

Results

A total of 9 articles were selected for review concerning PPE. In general, the design and fabrication of PPE were moving toward the direction of additive manufacturing and intelligent information feedback while being eco-friendly. Moreover, 8 articles were selected for reviewing testing methods within the two main categories of molecular and antigen tests. All the inventions endeavored to increase sensitivity while reducing the turnaround time. However, the inventions reported in this review paper were not sufficiently tested for their safety and efficiency. Most of the inventions are temporary solutions intended to be used only during shortages of medical resources. Finally, 6 articles were selected for the review of COVID-19 medical treatment. The major challenge identified was the uncertainty in applying novel ideas to speed up the production of ventilators.

Conclusions

The technologies developed during the COVID-19 pandemic were considered for review. In order to better respond to future pandemics, national reserves of critical medical supplies should be increased to improve preparation. This pandemic has also highlighted the need for the automation and optimization of medical manufacturing.

Quality versus emergency: How good were ventilation fittings produced by additive manufacturing to address shortages during the COVID19 pandemic?

OBJECTIVE

The coronavirus disease pandemic (COVID-19) increased the risk of shortage in intensive care devices, including fittings with intentional leaks. 3D-printing has been used worldwide to produce missing devices. Here we provide key elements towards better quality control of 3D-printed ventilation fittings in a context of sanitary crisis.

MATERIAL AND METHODS

Five 3D-printed designs were assessed for non-intentional (junctional and parietal) and intentional leaks: 4 fittings 3D-printed in-house using FDeposition Modelling (FDM), 1 FDM 3D-printed fitting provided by an independent maker, and 2 fittings 3D-printed in-house using Polyjet technology. Five industrial models were included as controls. Two values of wall thickness and the use of coating were tested for in-house FDM-printed devices.

RESULTS

Industrial and Polyjet-printed fittings had no parietal and junctional leaks, and satisfactory intentional leaks. In-house FDM-printed fittings had constant parietal leaks without coating, but this post-treatment method was efficient in controlling parietal sealing, even in devices with thinner walls (0.7 mm vs 2.3 mm). Nevertheless, the use of coating systematically induced absent or insufficient intentional leaks. Junctional leaks were constant with FDM-printed fittings but could be controlled using rubber junctions rather than usual rigid junctions. The properties of Polyjet-printed and FDM-printed fittings were stable over a period of 18 months.

CONCLUSIONS

3D-printing is a valid technology to produce ventilation devices but requires care in the choice of printing methods, raw materials, and post-treatment procedures. Even in a context of sanitary crisis, devices produced outside hospitals should be used only after professional quality control, with precise data available on printing protocols. The mechanical properties of ventilation devices are crucial for efficient ventilation, avoiding rebreathing of CO2, and preventing the dispersion of viral particles that can contaminate health professionals. Specific norms are still required to formalise quality control procedures for ventilation fittings, with the rise of 3D-printing initiatives and the perspective of new pandemics.

The personal protective equipment fabricated via 3D printing technology during COVID-19

COVID-19 has been spread in more than 220 countries and caused global health concerns. The supply chain disruptions have abruptly affected due to the second wave of COVID-19 in various countries and caused unavailability and shortage of medical devices and personal protective equipment for frontline healthcare workers. Three-dimensional (3D) printing has proven to be a boon and revolutionized technology to supply medical devices and tackle the situation caused by the COVID-19 pandemic. The diverse designs were produced and are currently used in hospitals by patients and frontline healthcare doctors. This review summarises the application of 3D printing during COVID-19. It collects the comprehensive information of recently designed and fabricated protective equipment like nasopharyngeal swabs, valves, face shields, facemasks and many more medical devices. The drawbacks and future challenges of 3D printed medical devices and protective equipment is discussed.

Stereolithography 3D Printing of a Heat Exchanger for Advanced Temperature Control in Wire Myography

We report the additive manufacturing of a heat-exchange device that can be used as a cooling accessory in a wire myograph. Wire myography is used for measuring vasomotor responses in small resistance arteries; however, the commercially available devices are not capable of active cooling. Here, we critically evaluated a transparent resin material, in terms of mechanical, structural, and thermal behavior. Tensile strength tests (67.66 ± 1.31 MPa), Charpy impact strength test (20.70 ± 2.30 kJ/m²), and Shore D hardness measurements (83.0 ± 0.47) underlined the mechanical stability of the material, supported by digital microscopy, which revealed a glass-like structure. Differential scanning calorimetry with thermogravimetry analysis and thermal conductivity measurements showed heat stability until ~250 °C and effective heat insulation. The 3D-printed heat exchanger was tested in thermophysiology experiments measuring the vasomotor responses of rat tail arteries at different temperatures (13, 16, and 36 °C). The heat-exchange device was successfully used as an accessory of the wire myograph system to cool down the experimental chambers and steadily maintain the targeted temperatures. We observed temperature-dependent differences in the vasoconstriction induced by phenylephrine and KCl. In conclusion, the transparent resin material can be used in additive manufacturing of heat-exchange devices for biomedical research, such as wire myography. Our animal experiments underline the importance of temperature-dependent physiological mechanisms, which should be further studied to understand the background of the thermal changes and their consequences.

3D Printing in Eye Care

Three-dimensional printing enables precise modeling of anatomical structures and has been employed in a broad range of applications across medicine. Its earliest use in eye care included orbital models for training and surgical planning, which have subsequently enabled the design of custom-fit prostheses in oculoplastic surgery. It has evolved to include the production of surgical instruments, diagnostic tools, spectacles, and devices for delivery of drug and radiation therapy. During the COVID-19 pandemic, increased demand for personal protective equipment and supply chain shortages inspired many institutions to 3D-print their own eye protection. Cataract surgery, the most common procedure performed worldwide, may someday make use of custom-printed intraocular lenses. Perhaps its most alluring potential resides in the possibility of printing tissues at a cellular level to address unmet needs in the world of corneal and retinal diseases. Early models toward this end have shown promise for engineering tissues which, while not quite ready for transplantation, can serve as a useful model for in vitro disease and therapeutic research. As more institutions incorporate in-house or outsourced 3D printing for research models and clinical care, ethical and regulatory concerns will become a greater consideration. This report highlights the uses of 3D printing in eye care by subspecialty and clinical modality, with an aim to provide a useful entry point for anyone seeking to engage with the technology in their area of interest.

Combining Chromatographic, Rheological, and Mechanical Analysis to Study the Manufacturing Potential of Acrylic Blends into Polyacrylic Casts

Polyacrylics have been considered for a broad range of material applications, including coatings, dental applications, and adhesives. In this experimental study, the casting potential of a group of (co)monomers belonging to the acrylic family has been explored to enable a more sustainable use of these polymer materials in the medical and veterinary science field. The individual contributions of each comonomer have been analyzed, the reaction conversion has been studied via gas chromatography (GC), the rheological behavior has been characterized via stress-controlled measurements, and the final mechanical properties have been obtained from tensile, flexure, and impact tests. The GC results allow assessing the pot life and thus the working window of the casting process. For the rheological measurements, which start from low-viscous mixtures, a novel protocol has been introduced to obtain accurate absolute data. The rheological data reflect the time dependencies of the GC data but facilitate a more direct link with the macroscopic material data. Specifically, the steep increase in the viscosity with increasing reaction time for the methyl methacrylate (MMA)/ethylene glycol dimethyl methacrylate (EGDMA) case (2% crosslinker) allows maximizing several mechanical properties: the tensile/flexure modulus, the tensile/flexure stress at break, and the impact strength. This opens the pathway to more dedicated chemistry design for corrosion casting and polyacrylic material design in general.

Blockchain-Based Decentralized Digital Manufacturing and Supply for COVID-19 Medical Devices and Supplies

Coronavirus 2019 (COVID-19) has disclosed the deficiencies and limitations of the existing manufacturing and supply chain systems used for medical devices and supplies. It enforces the necessity to accelerate the shift towards decentralized digital manufacturing and supply chain networks. This paper proposes a blockchain-based solution for decentralized digital manufacturing of medical devices and their supply. We develop Ethereum smart contracts to govern and track transactions in a decentralized, transparent, traceable, auditable, trustworthy, and secure manner. This allows overcoming certain issues hindering the transition towards decentralized digital manufacturing and supply, including trusted traceability, attestations, certifications, and secured intellectual property (IP) rights. We incorporate the decentralized storage of the InterPlanetary file system (IPFS) into the Ethereum blockchain to store and fetch Internet of things (IoT)-based devices records and additional manufacturing and supply details. We present the system architecture and algorithms along with their full implementation and testing details. Furthermore, we present cost and security analyses to show that the proposed solution is cost-efficient and resilient against well-known vulnerabilities and security attacks. We make our smart contracts code publicly available on GitHub.

Manufacturing a First Upper Molar Dental Forceps Using Continuous Fiber Reinforcement (CFR) Additive Manufacturing Technology with Carbon-Reinforced Polyamide

3D printing is an emerging and disruptive technology, supporting the field of medicine over the past decades. In the recent years, the use of additive manufacturing (AM) has had a strong impact on everyday dental applications. Despite remarkable previous results from interdisciplinary research teams, there is no evidence or recommendation about the proper fabrication of handheld medical devices using desktop 3D printers. The aim of this study was to critically examine and compare the mechanical behavior of materials printed with FFF (fused filament fabrication) and CFR (continuous fiber reinforcement) additive manufacturing technologies, and to create and evaluate a massive and practically usable right upper molar forceps. Flexural and torsion fatigue tests, as well as Shore D measurements, were performed. The tensile strength was also measured in the case of the composite material. The flexural tests revealed the measured force values to have a linear correlation with the bending between the 10 mm (17.06 N at 5000th cycle) and 30 mm (37.99 N at 5000th cycle) deflection range. The findings were supported by scanning electron microscopy (SEM) images. Based on the results of the mechanical and structural tests, a dental forceps was designed, 3D printed using CFR technology, and validated by five dentists using a Likert scale. In addition, the vertical force of extraction was measured using a unique molar tooth model, where the reference test was carried out using a standard metal right upper molar forceps. Surprisingly, the tests revealed there to be no significant differences between the standard (84.80 N ± 16.96 N) and 3D-printed devices (70.30 N ± 4.41 N) in terms of extraction force in the tested range. The results also highlighted that desktop CFR technology is potentially suitable for the production of handheld medical devices that have to withstand high forces and perform load-bearing functions.

3D Printing for Medical Applications: Current State of the Art and Perspectives during the COVID-19 Crisis

The coronavirus SARS-CoV-2 pandemic has affected over one hundred million people worldwide and has resulted in over two million deaths. In addition to the toll that coronavirus takes on the health of humans infected with the virus and the potential long term effects of infection, the repercussions of the pandemic on the economy as well as on the healthcare system have been enormous. The global supply of equipment necessary for dealing with the pandemic experienced extreme stress as healthcare systems around the world attempted to acquire personal protective equipment for their workers and medical devices for treating COVID-19. This review describes how 3D printing is currently being used in life saving surgeries such as heart and lung surgery and how 3D printing can address some of the worldwide shortage of personal protective equipment, by examining recent trends of the use of 3D printing and how these technologies can be applied during and after the pandemic. We review the use of 3D printed models for treating the long term effects of COVID-19. We then focus on methods for generating face shields and different types of respirators. We conclude with areas for future investigation and application of 3D printing technology.

Community-driven PPE production using additive manufacturing during the COVID-19 pandemic: Survey and lessons learned

This study presents a detailed analysis of the production efforts for personal protective equipment in makerspaces and informal production spaces (i.e., community-driven efforts) in response to the COVID-19 pandemic in the United States. The focus of this study is on additive manufacturing (also known as 3D printing), which was the dominant manufacturing method employed in these production efforts. Production details from a variety of informal production efforts were systematically analyzed to quantify the scale and efficiency of different efforts. Data for this analysis was primarily drawn from detailed survey data from 74 individuals who participated in these different production efforts, as well as from a systematic review of 145 publicly available news stories. This rich dataset enables a comprehensive summary of the community-driven production efforts, with detailed and quantitative comparisons of different efforts. In this study, factors that influenced production efficiency and success were investigated, including choice of PPE designs, production logistics, and additive manufacturing processes employed by makerspaces and universities. From this investigation, several themes emerged including challenges associated with matching production rates to demand, production methods with vastly different production rates, inefficient production due to slow build times and high scrap rates, and difficulty obtaining necessary feedstocks. Despite these challenges, nearly every maker involved in these production efforts categorized their response as successful. Lessons learned and themes derived from this systematic study of these results are compiled and presented to help inform better practices for future community-driven use of additive manufacturing, especially in response to emergencies.

How to Sterilize Polylactic Acid Based Medical Devices?

How sterilization techniques accurately affect the properties of biopolymers continues to be an issue of discussion in the field of biomedical engineering, particularly now with the development of 3D-printed devices. One of the most widely used biopolymers in the manufacture of biomedical devices is the polylactic acid (PLA). Despite the large number of studies found in the literature on PLA devices, relatively few papers focus on the effects of sterilization treatments on its properties. It is well documented in the literature that conventional sterilization techniques, such as heat, gamma irradiation and ethylene oxide, can induced damages, alterations or toxic products release, due to the thermal and hydrolytical sensitivity of PLA. The purposes of this paper are, therefore, to review the published data on the most common techniques used to sterilize PLA medical devices and to analyse how they are affecting their physicochemical and biocompatible properties. Emerging and alternative sterilization methods for sensitive biomaterials are also presented.

3D-Printing to Mitigate COVID-19 Pandemic

3D-printing technology provided numerous contributions to the health sector during the recent Coronavirus disease 2019 (COVID-19) pandemic. Several of the 3D-printed medical devices like personal protection equipment (PPE), ventilators, specimen collectors, safety accessories, and isolation wards/ chambers were printed in a short time as demands for these were rising significantly. The review discusses some of these contributions of 3D-printing that helped to protect several lives during this health emergency. By enlisting some of the significant benefits of using the 3D-printing technique during an emergency over other conventional methods, this review claims that the former opens enormous possibilities in times of serious shortage of supply and exceeding demands. This review acknowledges the collaborative approaches adopted by individuals, entrepreneurs, academicians, and companies that helped in forming a global network for delivering 3D-printed medical/non-medical components, when other supply chains were disrupted. The collaboration of the 3D-printing technology with the global health community unfolds new and significant opportunities in the future.

The therapeutic potential of inorganic polyphosphate: A versatile physiological polymer to control coronavirus disease (COVID-19)

Rationale: The pandemic caused by the novel coronavirus SARS-CoV-2 is advancing rapidly. In particular, the number of severe courses of the disease is still dramatically high. An efficient drug therapy that helps to improve significantly the fatal combination of damages in the airway epithelia, in the extensive pulmonary microvascularization and finally multiorgan failure, is missing. The physiological, inorganic polymer, polyphosphate (polyP) is a molecule which could prevent the initial phase of the virus life cycle, the attachment of the virus to the target cells, and improve the epithelial integrity as well as the mucus barrier. Results: Surprisingly, polyP matches perfectly with the cationic groove on the RBD. Subsequent binding studies disclosed that polyP, with a physiological chain length of 40 phosphate residues, abolishes the binding propensity of the RBD to the ACE2 receptor. In addition to this first mode of action of polyP, this polymer causes in epithelial cells an increased gene expression of the major mucins in the airways, of MUC5AC and MUC1, as well as a subsequent glycoprotein production. MUC5AC forms a gel-like mucus layer trapping inhaled particles which are then transported out of the airways, while MUC1 constitutes the periciliary liquid layer and supports ciliary beating. As a third mode of action, polyP undergoes enzymatic hydrolysis of the anhydride bonds in the airway system by alkaline phosphatase, releasing metabolic energy. Conclusions: This review summarizes the state of the art of the biotherapeutic potential of the polymer polyP and the findings from basic research and outlines future biomedical applications.

Rotating Bending Fatigue Analysis of Printed Specimens from Assorted Polymer Materials

Fused filament fabrication (FFF), as a form of additive manufacturing (AM), in recent years, has become a popular method to manufacture prototypes, as well as functional parts. FFF is an extrusion process, commonly known as 3D printing, where the object is built by depositing melted material layer by layer. The most common materials, i.e., the materials that are most widely used, are polylactic acid (PLA), acrylonitrile butadiene styrene (ABS) and acrylonitrile styrene acrylate (ASA). Although there are lot of research papers that cover the subject of the determination of mechanical properties and characteristics, theoretically and experimentally, as well as the fatigue characteristics of aforementioned materials, there is a lack of research and scientific papers dealing with the problematics of S–N curves based on the rotating bending fatigue analysis of those materials. Consequently, this paper covers the topic of rotating bending fatigue data for 3D printed specimens of given materials, under different loading values.

A Novel Bespoke Hypertrophic Scar Treatment: Actualizing Hybrid Pressure and Silicone Therapies with 3D Printing and Scanning

The treatment of hypertrophic scars (HSs) is considered to be the most challenging task in wound rehabilitation. Conventional silicone sheet therapy has a positive effect on the healing process of HSs. However, the dimensions of the silicone sheet are typically larger than those of the HS itself which may negatively impact the healthy skin that surrounds the HS. Furthermore, the debonding and displacement of the silicone sheet from the skin are critical problems that affect treatment compliance. Herein, we propose a bespoke HS treatment design that integrates pressure sleeve with a silicone sheet and use of silicone gel using a workflow of three-dimensional (3D) printing, 3D scanning and computer-aided design, and manufacturing software. A finite element analysis (FEA) is used to optimize the control of the pressure distribution and investigate the effects of the silicone elastomer. The result shows that the silicone elastomer increases the amount of exerted pressure on the HS and minimizes unnecessary pressure to other parts of the wrist. Based on this treatment design, a silicone elastomer that perfectly conforms to an HS is printed and attached onto a customized pressure sleeve. Most importantly, unlimited scar treating gel can be applied as the means to optimize treatment of HSs while the silicone sheet is firmly affixed and secured by the pressure sleeve.