Additive manufacturing of patient specific implants made of biodegradable polymers is receiving increasing attention in the medical sector, including the trend towards manufacturing at the point-of-care. Despite this, the changes of the polymer structure and their effects on mechanical properties and degradation behavior caused by the additive manufacturing process and subsequent sterilization are still insufficiently investigated, although of key relevance for the implant's functionality. In this study, poly(p-dioxanone) (PPDO) was processed by fused filament fabrication (FFF). The effects of manufacturing as well as two different low-temperature sterilization techniques, namely H2O2 plasma and gamma irradiation, on the polymer structure were evaluated. Additionally, PPDO degradation was investigated by immersing the processed samples in Sorensen's phosphate buffer (PB) with pH = 6.47 for 28 days to mimic implantation in intestinal milieu and evaluated at regular time intervals. Results showed that we were able to successfully print PPDO without influencing the polymer structure or cytocompatibility. No significant changes were detected for plasma-sterilized samples (PS) while gamma-sterilized (GS) ones significantly decreased molecular weight (Mw and Mn) and showed significant lower inherent viscosity (IV) compared with the (non-sterilized) control group after processing. During immersion in PB, a decrease in Mw, Mn, and mechanical strength occurred for all samples. However, GS samples were affected to a much higher extent compared with the other groups both in final values and timeline. A degradation plateau was seen for the tensile strength of NS and PS samples over the first 21 and 17 days, respectively, followed by a steady decrease. In contrast, for the GS samples, a drastic decrease in tensile strength occurred already during the first 14 days. There was no notable mass loss detected within the first 28 days of degradation for any of the sample groups. Based on these results, we conclude that FFF with subsequent plasma sterilization is a reliable process for manufacturing PPDO devices for short-term applications that require stable mechanical conditions within the first weeks of implantation to guarantee the time needed for tissue healing before degrading, as for example, in the case of intestinal compression anastomoses. Such requirement could not be met with gamma sterilization with the dose used, because of the too fast decrease in mechanical properties.

This study aimed to identify the sources, types, and volumes of medical plastic waste generated at Adama Hospital Medical College and to evaluate its recyclability potential during the 2022–2023 period. Accordingly, 19 plastic items were identified, categorized into 6 classes based on their application and contamination. Mass of identified product was multiplied by the number of the consumed product to determine total consumption. Annual plastic product consumption was calculated for each product and analyzed in terms of polymer composition of the plastic products. Accordingly, 38 tons of medical plastic products were consumed directly from hospital stock while 9.5 tons of plastic medical supplies were brought into the hospital by patients annually. Personal protective equipment ranked first and accounted for 52

Medical plastic waste management is a growing global concern, especially in healthcare settings. The study focused on the implementation of medical plastic waste segregation at the point of use in four wards of the KNUST Hospital, Kumasi (Ghana). Specifically, targeted products, such as syringes and intravenous bags made of polypropylene and polyethylene, that have not come into contact with blood or bodily fluids were collected to obtain raw materials for a mechanical recycling setup. Autoclave sterilization was found not practically suitable for medical plastic waste decontamination for mechanical recycling. Continuous awareness creation, training, repeated short presentations at staff meetings and staff inductions, and quality checks are cardinal to implementing an effective medical waste collection system. The average daily weight for the IV bag and syringe were about 0.5 kg and 0.3 kg, respectively. This translates to 0.8 kg of total raw material daily and about 4 kilograms weekly. Contamination was assessed using the Pour Plate method, with decontamination conducted using 5

Purpose:Anastomosis creation after resective gastrointestinal surgery is a crucial task. The present review examines the techniques and implants currently available for anastomosis creation and analyses to which extent they already address our clinical needs, with a special focus on their potential to enable further trauma minimization in visceral surgery. Methods:A multi-database research was conducted in MEDLINE, Scopus, and Cochrane Library. Comparative controlled and uncontrolled clinical trials dealing with anastomosis creation techniques in the intestinal tract in both German and English were included and statistically significant differences in postoperative complication incidences were assessed using the RevMan5.4 Review Manager (Cochrane Collaboration, Oxford, UK). Results:All methods and implant types were analyzed and compared with respect to four dimensions, assessing the techniques' current performances and further potentials for surgical trauma reduction. Postoperative outcome measures, such as leakage, stenosis, reoperation and mortality rates, as well as the tendency to cause bleeding, wound infections, abscesses, anastomotic hemorrhages, pulmonary embolisms, and fistulas were assessed, revealing the only statistically significant superiority of hand-suture over stapling anastomoses with respect to the occurrence of obstructions. Conclusion:Based on the overall complication rates, it is concluded that none of the anastomosis systems addresses the demands of operative trauma minimization sufficiently yet. Major problems are furthermore either low standardization potentials due to dependence on the surgeons' levels of experience, high force application requirements for the actual anastomosis creation, or large and rigid device designs interfering with flexibility demands and size restrictions of the body's natural access routes. There is still a need for innovative technologies, especially with regard to enabling incisionless interventions.

Gastro oesophagael reflux disease (GORD) is common in the Western hemisphere. Patients with regurgitated reflux are typically treated with fundoplication surgery. We present a newly designed polyurethane implant which passively aids the sphincter in reducing gastric fluids within the oesophagus. The gastric implant has an open porous inner side which allows for tissue ingrowth from the oesophagus and thus allows for fixation around the sphincter. In addition, a device for minimally invasive surgery of this implant was developed and used in a pig model. The unmodified GORD implant was placed around the pig’s oesophagus with unsatisfactory results, leading to insufficient fixation at the implantation site and scarring tissue leading to dysphagia. In addition, two surface modifications, plasma activation and TiO 2 deposition were used to improve the implant’s host tissue response. The biocompatibility effects of the surface treatments and sterilisation method on the implant were investigated in vitro and in vivo. In vitro tests found that the plasma activation and TiO2 deposition have effectively enhanced the surface hydrophilicity and, consequently, the cell response to the implant. In addition, the gamma sterilisation harmed the plasma-activated implant. The plasma activation was more effective than TiO 2 deposition as a surface treatment method for improving the tissue response of this implant in vivo. In addition, the in vivo experiment proved tissue ingrowth as deep as 1 mm into the porous structure of the implant. The GORD implants were encapsulated wholly in fibrous tissue; however, the capsule thickness diminished over time. Finally, the TiO 2 -coated implants showed the poorest histocompatibility, contradictory to the in vitro findings. This study shows that it is possible to produce a plasma-treated porous polyurethane gastric implant that allows for fibrous tissue ingrowth, reduced in vivo encapsulation, and enhanced chemical properties. Graphical Abstract Model of the implant with an inner porous and an outer non-porous surface. The hypothesis was that the porous surface allows for fibroblastic infiltration into the porous structure (A) and fixation by scarring at the point of implantation, the lower oesophageal sphincter (LOS). The outer side is smooth (B), which hinders neighbouring tissue attachments. In addition, a Nitinol ring (C) aids the implant in exerting pressure around the LOS, thus reducing sphincter volume. In addition, this metal ring aids visualisation with, e.g. X-ray or CT during post-therapy follow-ups. The open, flexible design eases the freeing of the ring in a stretched position and placement around the cardia (D-F). The internal diameter of 28 mm prevents stenosis but markedly reinforces the lower oesophagal sphincter. In addition, its size allows for minimally invasive surgery.

The transmission of pathogens via surfaces poses a major health problem, particularly in hospital environments. Antimicrobial surfaces can interrupt the path of spread, while photocatalytically active titanium dioxide (TiO2) nanoparticles have emerged as an additive for creating antimicrobial materials. Irradiation of such particles with ultraviolet (UV) light leads to the formation of reactive oxygen species that can inactivate bacteria. The aim of this research was to incorporate TiO2 nanoparticles into a cellulose-reinforced melamine-formaldehyde resin (MF) to obtain a photocatalytic antimicrobial thermoset, to be used, for example, for device enclosures or tableware. To this end, composites of MF with 5, 10, 15, and 20 wt% TiO2 were produced by ultrasonication and hot pressing. The incorporation of TiO2 resulted in a small decrease in tensile strength and little to no decrease in Shore D hardness, but a statistically significant decrease in the water contact angle. After 48 h of UV irradiation, a statistically significant decrease in tensile strength for samples with 0 and 10 wt% TiO2 was measured but with no statistically significant differences in Shore D hardness, although a statistically significant increase in surface hydrophilicity was measured. Accelerated methylene blue (MB) degradation was measured during a further 2.5 h of UV irradiation and MB concentrations of 12% or less could be achieved. Samples containing 0, 10, and 20 wt% TiO2 were investigated for long-term UV stability and antimicrobial activity. Fourier-transform infrared spectroscopy revealed no changes in the chemical structure of the polymer, due to the incorporation of TiO2, but changes were detected after 500 h of irradiation, indicating material degradation. Specimens pre-irradiated with UV for 48 h showed a total reduction in Escherichia coli when exposed to UV irradiation.

Purpose The introduction of novel endoscopic instruments is essential to reduce trauma in visceral surgery. However, endoscopic device development is hampered by challenges in respecting the dimensional restrictions, due to the narrow access route, and by achieving adequate force transmission. As the overall goal of our research is the development of a patient adaptable, endoscopic anastomosis manipulator, biomechanical and size-related characterization of gastrointestinal organs are needed to determine technical requirements and thresholds to define functional design and load-compatible dimensioning of devices. Methods We built an experimental setup to measure colon tissue compression piercing forces. We tested 54 parameter sets, including variations of three tissue fixation configurations, three piercing body configurations (four, eight, twelve spikes) and insertion trajectories of constant velocities (5 mms −1 , 10 mms −1 ,15 mms −1 ) and constant accelerations (5 mms −2 , 10 mms −2 , 15 mms −2 ) each in 5 samples. Furthermore, anatomical parameters (lumen diameter, tissue thickness) were recorded. Results There was no statistically significant difference in insertion forces neither between the trajectory groups, nor for variation of tissue fixation configurations. However, we observed a statistically significant increase in insertion forces for increasing number of spikes. The maximum mean peak forces for four, eight and twelve spikes were 6.4 ± 1.5 N, 13.6 ± 1.4 N and 21.7 ± 5.8 N, respectively. The 5th percentile of specimen lumen diameters and pierced tissue thickness were 24.1 mm and 2.8 mm, and the 95th percentiles 40.1 mm and 4.8 mm, respectively. Conclusion The setup enabled reliable biomechanical characterization of colon material, on the base of which design specifications for an endoscopic anastomosis device were derived. The axial implant closure unit must enable axial force transmission of at least 28 N (22 ± 6 N). Implant and applicator diameters must cover a range between 24 and 40 mm, and the implant gap, compressing anastomosed tissue, between 2 and 5 mm.

We present a photocurable, biocompatible, and flexible silicone-hydrogel hybrid material for stereolithographic (SLA) printing of biomedical devices. The silicone-hydrogel polymer is similar to mixtures used for contact lenses. It is flexible and stretchable with a Young's modulus of 78 MPa and a maximum elongation at break of 51%, shows a low degree of swelling (<4% v/v) in water, and can be bonded easily to flat glass substrates via a surface-modification method. The in vitro cytotoxicity of the material is assessed with a WST-8 cell viability assay using five different cell lines: HT1080, L929, and Hs27 fibroblasts, cardiomyocyte-like HL-1 cells, and neuronal-phenotype PC-12 cells. On this account, the silicone-hydrogel polymer is compared to several other common SLA printing materials used for cell-culture applications and polydimethylsiloxane (PDMS). A simple extraction step in water is sufficient for reaching biocompatibility of the material with respect to the tested cell types. The oxygen permeability of the silicone-hydrogel material is investigated and compared to that of PDMS, Medicalprint clear-a commercial resin for medical products, and a short-chain hydrogel-based resin. As a proof of concept, we demonstrate a 3D-printed microfluidic device with integrated valves and mixers. Furthermore, we show a printed culture chamber for analyzing signal propagation in HL-1 cardiomyocyte cell networks. Ca2+ imaging is used to observe the signal propagation through the cardiac cell layers grown in the microchannels. The cells are shown to maintain normal electrophysiological activity within the printed chambers. Overall, the biocompatible silicone-hydrogel material will be an advancement for SLA printing in cell-culture and microfluidic lab-on-a-chip applications.

Germs are present in all areas of everyday life and can lead to dangerous infections. Surfaces with antimicrobial properties are used to reduce the risk of infection in sanitary facilities and hospitals. Apart from the addition of biocides or antibiotic agents to synthetic materials, research shows that it is possible to use the semiconductor titanium dioxide (TiO2) to generate antibacterial surfaces. Photocatalytically active TiO2 leads to the development of reactive oxygen species (ROS) that are able to kill germs. The aim of this research is to use TiO2 to generate antibacterial bulk material. Nanostructured TiO2 particles were incorporated into silicone rubber to obtain a photocatalytic active polymer surface. High temperature vulcanizing (HTV) silicone rubber was used as a matrix material, and samples with 10 wt% of TiO2 were produced. The distribution of TiO2 particles in the matrix was analyzed via light microscopy. The photocatalytic activity on the surface of the test samples was studied via microbial testing with E.coli bacteria. The samples showed different intensities of the photocatalytic effect depending on the type of additive. The effort to create a germ reducing silicone rubber surface by using TiO2 as an additive was successful.

Computer-aided design and computer-aided manufacturing (CAD/CAM) technology has been implemented in the treatment of cleft lip and palates (CLP) by several research groups. This pilot study presents a technique that combines intraoral molding with a semi-automated plate generation and 3D-printing. The clinical results of two intraoral molding approaches are compared. This is the first clinical investigation of semi-automated intraoral molding. Our study included newborns with unilateral CLP. Plaster models were digitalized and measured by two independent observers. Two methods of CAD/CAM-assisted intraoral molding were compared: (i) stepwise manual design of molding plates (conventional CAD/CAM-intraoral molding) and (ii) a semi-automated approach with an automated detection of alveolar ridges (called RapidNAM) assisted by a graphical user interface (GUI). Both approaches significantly narrowed the clefts and resulted in a harmonic alveolar crest alignment. The GUI was easy to use and generated intraoral molding devices within minutes. The presented design solution is an efficient technical refinement with good clinical results. The semi-automated plate generation with a feasible GUI is fast but allows individual adaptations. This promising technique might facilitate and foster the more widespread use of CAD/CAM-technology in intraoral molding therapy.

Bacteria are present in all areas of everyday life and can lead to dangerous infections. Surfaces with antimicrobial properties are used to reduce the risk of infection in sanitary facilities and hospitals. Apart from the addition of biocides or antibiotic agents to synthetic materials, recent research show, that it is possible to use the semiconductor titanium dioxide (TiO2) to generate antibacterial surfaces. The photocatalytically active TiO2 leads to the development of reactive oxygen species (ROS) that are able to kill bacteria. The aim of this research is to generate silicone rubbers with a photocatalytically active surface that has the possibility to lead to an antimicrobial property by incorporating the additive TiO2 into the bulk material. AEROXIDE (R) TiO2 P25 was used. As matrix material representatives of the three silicone rubber classes were tested. A room-temperature-vulcanization silicone rubber (RTV), a liquid silicone rubber (LSR) and a high-temperature-vulcanization silicone rubber (HTV) were examined. Compounds with various concentrations of TiO2 were produced and the influence on the cross-linking reaction was investigated using differential scanning calorimetry (DSC). The photocatalytic effect on the surface of the modified material was studied via contact angle measurements and methylene blue tests. The DSC analysis showed that titanium dioxide inhibits the curing of the additivated RTV and LSR. The incorporation of TiO2 in the HTV matrix material up to 15 wt% was possible, with an extension of the cross-linking time. The investigation of the HTV siivone rubbers considering the photocatalytic effect yield different results. While the expected photo-induced hydrophilic effect could not be verified for the modified HTV silicone rubbers. However the methylene blue trial showed a high significant discoloration of the titanium dioxide addtivtated HTV polymer and proves that a photocatalytic active HTV silicone rubber surface can be produced using the additive titanium dioxide.

Equipping medical devices with smart technologies holds great potential for the development of modern medical products. The development requires the identification of new integration strategies and the research of new material combinations due to the miniaturization of systems and increasing production figures. The realization of Smart Biomedical Devices requires a sufficient barrier effect (bioprotection) by appropriate encapsulation of the electronic components. Thinnest polymer coatings have proven to be suitable for conformal encapsulation. The aim of the study was to investigate the fundamental suitability of thin-film lacquers added with catalysts as coating materials for electronic systems with regard to their biological use. Due to long curing times of up to 14 days, eight different catalysts based on different chemical structures were added to the coating materials and their influence on a cytotoxic effect was investigated. A non-cytotoxic effect was observed for the organometallic catalysts based on tin, zirconium, titanium, bismuth, and tertiary amine. Most were resistant to steam sterilization. The curing time of the non-cytotoxic coatings could be significantly reduced by the addition of catalysts. The shortening of process times is an important economic aspect in the production of mass-produced Smart Biomedical Devices.

The integration of low-cost electronic components into medical plastic parts for sensory data acquisition will be an essential feature of innovative medical products in the future. The realization of these wireless communicating Smart Biomedical Devices requires sufficient bioprotection by appropriate encapsulation of the toxic electronic components. These, however, influence wireless communication. The aim of the study was to investigate the influence of thin-walled conformal coated polymer lacquers on an electrically small antenna (ESA) of the type split ring resonator (SRR). The antenna was developed in order to derive integration strategies of UHF RFID antenna structures into medical products. To predict the signal transmission behavior of the antenna, eight different lacquers were used, which were tested for biocompatibility in previous studies. All coating materials examined showed a detuning of up to 50 Hz and an increase of the input reflection attenuation S11 of up to 50 % at layer heights of approximately 30-200 micrometer and relative permittivities up to epsilonr = 5 with complete coating on the top and bottom layer of the PCB. The results allow conclusions to be drawn about the relationship between dry film thickness, dielectric properties, and the influence on the radiation and transmission behavior of the ESA. Concrete recommendations for integration strategies in Smart Biomedical Devices could be identified based on the results.

The design of Smart Biomedical Devices will be a defining element of future research in the context of intelligent medical devices for the Internet of Medical Things (IoMT). A prerequisite for serving the disposable market is the use of cost-effective electronic components and the highest reliability of the developed products in terms of biocompatibility and bioprotection. In the study, resistors, capacitors, and light-emitting diodes, different in their materials and construction forms, were examined. The selected types represented electronic components as they are commonly installed on electronic system from the segment of low-cost standard components. These were subjected to steam sterilization with up to 50 cycles, gamma sterilization, and a CCK-8 assay to test in vitro cytotoxicity. Functional failure could not be determined for any component. Gamma sterilization did not result in significant changes in resistance values, but in capacitors with barium titanate as dielectric. Non-cytotoxic electronic components could be identified. The results show that certain electronic standard components are suitable for disposable Smart Biomedical Devices.

For bioprotective encapsulated Internet of Things (IoT) electronics for the medical market, especially for cost‐effective, single or multiple use, injection molding will be of major importance. The stresses from the production process pose special challenges for electronics. The aim of the study was the simulative and experimental characterization of the load spectrum from the injection molding process and its effects on electronics. General recommendations for the encapsulation of IoT electronics in polymer matrices were derived. A microcontroller‐controlled temperature sensor board and a suitable injection mold were developed. Eight circumferential NTC‐sensors measured the prevailing thermal load directly on the component during overmolding. A simulation model allowed statements on the loads to be made about individual components, validated in experimental tests. In addition to PP and PMMA, PSU with a melt temperature of 360°C was tested. The temperature influence of the melt could be described as a function of the component position. The loss of adhesion, shrinkage, distortion, cavities, and delamination were analyzed using micrograph analysis. Complete functionality of the electronics was ensured after encapsulation. Optimization strategies were developed for the design of both IoT electronics and the injection mold. Novel concepts such as interlayer or backfill vias could be derived for future research approaches. POLYM. ENG. SCI., 59:1315–1331 2019. © 2019 Society of Plastics Engineers

The anastomosis of two bowel segments is one of the core competences in visceral surgery. However, postoperative complication rates and intraoperative trauma are still too high despite numerous methods and products available. The aim of this paper is to show the first approach towards the development of a transluminal system to enable micro invasive anastomosing just using natural orifices. In this context a requirements analysis based on expert discussions and literature evaluation focusing on postoperative complications was carried out. A testing model was developed and a pressure test setup was designed to derive optimal compression zone geometry, based on the material behavior of porcine bowel tissue. For the task of transluminal anastomization a highly adaptable and flexible system must be developed. From some initial experimental trials within an abstracted bowel model, we were able to reveal first promising results concerning feasibility of transluminal anastomosis generation. In the following an experimental protocol has to be developed to assess relevant parameters as a basis for an objective comparison of the different implant models.

Autologous platelet-rich blood derivatives are used in a variety of medical fields in which the enhancement of wound healing by applying growth factors released from platelets is an especially promising application. Treatment of the whole surface of large-area wounds with a small volume of blood derivatives is best achieved by spraying. In this study, we present a compact and self-contained spraying device without external connections such as a power supply or compressor. The biocompatible propellant R134a is used to aspirate and atomize the blood derivatives. A 3D-printed, two-substance nozzle functions as the operating unit, throttle, mixing zone and atomization unit. The spray characteristics were evaluated via experimental flow volume, cone and droplet size measurements. Biological evaluation was performed by flow cytometry comparing platelet activation in the blood derivatives before and after spraying, and PDGF ELISA comparing growth factor release, respectively. Homogeneity and morphology of the sprayed blood cells were evaluated with scanning electron microscopy. The results show that the developed spraying device has excellent spray characteristics with low mechanical impact on the cellular components of the blood derivatives. Our spraying device is a promising tool for applying evenly distributed platelet-rich blood derivatives to treatment sites.