Standard Syringe Research Articles

Evaluation of Injectate Distribution of the Middle Mental Nerve Block Within the Mandibular Canal in a Cadaveric Canine Model.

Awareness among veterinarians has increased regarding the need for comprehensive pain relief, but many companion animal veterinarians do not administer regional analgesia pre-emptively during dental procedures. The middle mental nerve (MMN) block desensitizes the ipsilateral mandibular incisor and canine teeth as well as soft tissues rostral to the delivery site. There is little published information on the efficacy of the MMN block in dogs. The objective of this study was to determine injectate distribution within the mandibular canal using a radiopaque contrast media/methylene blue solution. Half a milliliter of solution was injected within the opening of the middle mental foramen using a standard hypodermic syringe and a 25G x 25 mm needle. The course of the injectate was traced both via computed tomography (CT) and, in some cadavers, gross dissection. Post-treatment CT revealed that in 90% of the cases, the contrast diffused at least as far caudally as the mesial root of the third premolar tooth. The injectate was not identified within the canal of 5% of cadaveric mandibles examined. Although the solution used diffused caudally within the mandibular canal when injected using recommended clinical techniques, this may not completely represent the extent of clinical effects experienced in live patients. This technique also confirmed that the needle does not need to be advanced into the mandibular canal to achieve adequate diffusion to at least the mesial root of the third premolar tooth.

Air injector geometry affects passive bubble acoustic signatures

Understanding the passive acoustic signals of gas bubbles has become increasingly imporant due to their growing relevance in ambient marine acoustics and medical areas, as well as the recent search for dark matter by Bubble Chamber Detectors. Here the acoustic signatures of 2.24, 1.83, 1.75, 1.66 and 1.43 mm radii bubbles are reported experimentaly. They were generated by two different air injectors in a quiescent liquid, a standard plastic syringe tube and 97 degrees-rotated metallic needles. The evolution of the sound pulse over time is presented alongside simultaneous images of the bubbles detaching from the injector and moving freely in the liquid. The beat-wave phenomenon is the standard interference pattern between two sounds of slightly different frequencies, generating a beat-period envelope of “rosary chain” form. In this study, beats are observed when the bubble exhibits changes in its shape through Cassini-oval, trapezoid, ‘guitar pick’, ellipsoid and oblate shapes, which is in agreement with earlier results on bubble fragmentation in a locally sheared flow. Finally, theoretical curve fits of freely-oscillating, lightly-damped bubble sound emissions confirm that the beats are due to changes in the bubble shapes.

An assessment of exposed syringe inner walls as a route of exposure from hazardous drugs.

Maintaining safe working environments for health care personnel, especially for those who regularly handle hazardous drugs (HDs), is of utmost importance. Studies have shown that when closed system transfer devices (CSTDs) are used with standard open barrel syringes, cyclophosphamide (CP), a commonly used HD, is transferred to the syringe plunger during compounding or administration processes. This contamination can then be transferred to the work environment, endangering workers. The purpose of this study was to quantify HD contamination of the inner surface of standard open barrel syringes and to compare contamination levels between three commonly used HDs: 5-fluorouracil (5-FU), CP, and ifosfamide (IF). Each HD was transferred from a vial to an intravenous (IV) bag using a standard open barrel syringe and Becton, Dickinson and Company (BD) PhaSealTM CSTD connectors. Samples were taken from the inner surface of each of the syringe barrels to measure the amount of HD contamination. Each drug was tested 15 times and compared to a positive control. Significant amounts of each drug were transferred to the inner surfaces of the syringes. The average amounts of each drug measured were: 5-FU, 1327.7 ng (standard deviation [SD] = 873.6 ng); CP, 1074.8 ng (SD = 481.6 ng); and IF, 1700.0 ng (SD = 1098.1 ng). There was no statistically significant difference between the three drugs (p = 0.14). This study underscores the presence of HD contamination on standard open barrel syringe inner surfaces after transfer of drug from vial to syringe to IV bag. Such contamination could be spread in the working environment and expose health care workers to harm.

Feasibility demonstration of a device for vitreous liquid biopsy incidental to intravitreal injection.

VitreoDx is an experimental device enabling push-button collection of a neat vitreous liquid biopsy incidental to an intravitreal injection. We explored the ability of the device to collect a sample usable for proteomic biomarker discovery and testing. Pilot study using ex vivo human eyes. Non-vitrectomized, human eyes from nine donors 75-91 years of age were refrigerated in BSS and used within 5 days of death. Four VitreoDx devices fitted with 25G needles, and four staked needle insulin syringes with 30G needles, were inserted at equal intervals through the pars plana of each eye and held in place by a fixture. The sampling mode of each VitreoDx device was triggered to attempt to acquire a liquid biopsy up to 70 μL. The plunger of each insulin syringe was retracted to attempt to obtain a liquid biopsy with a maximum volume of 50 μL. Samples acquired with the VitreoDx were extracted to polypropylene cryovials, refrigerated to -80 ºC, and sent for offsite proteomic analysis by proximity extension assay with a focus on panels containing approved and pipelined drug targets for neovascular disease and inflammatory factors. Of the attempted liquid biopsies with the novel 25G VitreoDx, 92% (66 of 72) resulted in successful acquisition (>25 μL) while 89% (64 of 72) attempted by a traditional 30G needle resulted in a successful acquisition. Sample volume sufficient for proteomics array analysis was acquired by the VitreoDx for every eye. Detectable protein was found for 151 of 166 unique proteins assayed in at least 25% of eyes sampled by VitreoDx. The high acquisition rate achieved by the prototype was similar to that achieved in previous clinical studies where a standard syringe was used with a 25G needle to biopsy vitreous fluid directly prior to standard intravitreal injection. Successful aspiration rates were likewise high for 30G needles. Together, these suggest that it is possible to routinely acquire liquid vitreous biopsies from patients who typically receive intravitreal injections with an injection device using a standard size needle without a vitreous cutter. Protein analysis shows that proteins of interest survive the sampling mechanism and may have potential to direct care in the future.

Sample Injection for Real-Time Analysis (SIRTA) Using GC-MS with Cold EI.

There is a continual demand for advanced methods and instruments for real-time analysis (RTA). Most of the current RTA techniques based on MS involve ambient desorption ionization technology. However, flow injection of liquid extracted samples is another option without added modifications or cost to existing LC-MS instruments. In this work, we introduce a new RTA approach named sample injection for real-time analysis (SIRTA) using GC-MS with Cold EI. In SIRTA, the standard GC column is replaced with a 1 m long 0.1 mm I.D. fused silica capillary that connects the GC injector to the MS transfer-line of Cold EI. Thus, SIRTA with Cold EI imposes no need for any additional instrumentation; hence, it is characterized by zero added cost. Like in flow injection in MS of LC-MS, the sample is dissolved in ∼1 mL methanol or another solvent. Subsequently, the vial is placed in the GC-MS autosampler while using a standard syringe for injection without any GC separation. The analysis takes merely 0.2-0.7 min, ensuring rapid and consecutive analyses. Unlike standard EI, Cold EI enables SIRTA by taking advantage of its fly through open ion source to avoid overwhelming the ion source during the elution of solvents while still providing enhanced molecular ions for nearly all analytes. In this study, we demonstrated SIRTA Cold EI analysis of 12 compounds and 7 mixtures, including various prescription and illicit drugs, cannabis and petroleum samples, and other synthetic organic compounds including those with molecular weight up to 800 g/mol.

Pediatric parenteral nutrition and hydroperoxide toxicity: Evaluation of the effectiveness of photoprotection medical devices.

Exposure of parenteral nutrition (PN) to light induces hydroperoxide (HPO) formation whose toxicity, especially in pediatrics, is documented. In this context, we evaluated the efficacy of photoprotection medical devices used in our institution to protect PN from degradation after two different exposures to light. A mixed oil lipid emulsion (Smoflipid®) in standard or opaque syringes and a ternary PN mixture bags (Numetah®) with or without opaque overwrap were exposed for at least 420 min to a xenon lamp. Samples of Smoflipid® in standard or opaque syringes were also exposed for 24 h to conditions reproducing those of a neonatal intensive care unit. The use of opaque syringes for Smoflipid® administration or opaque overwraps for Numetah® administration reduced HPO formation by an average of 14% and 40%, respectively, compared to standard conditions after at least 420 min to a xenon lamp. When Smoflipid® samples were administered with standard or opaque syringes and exposed to a phototherapy lamp, the fold-change in the HPO concentration increased, respectively, by 6.3 or 5.4 at 24 h compared with syringes unexposed to phototherapy lamp. Although the observed differences were non-significant, it nonetheless appears prudent to use photoprotection of PN during administration, particularly in patients with immature or compromised antioxidant capacity.

Investigating the Use of Nonloss of Resistance Syringes for Epidural Insertion: Experience on a Mannequin

(Int J Obstet Anesth. 2022;52:103595) The Obstetric Anaesthetists’ Association (OAA) announced a supply disruption of the Portex Loss of Resistance (LOR) Syringe, a commonly used tool for epidural catheter insertion. Several studies have shown no difference in epidural insertion success rates when using LOR to saline or air. Other methods for epidural space identification are being considered yet limited research compares specific low-resistance syringes with standard syringes. This study aimed to compare specific LOR syringes with syringes commonly used in epidural insertion.

AURAL SYRINGING: A ONE SIZE FITS ALL SOLUTION FOR EAR FOREIGN BODIES?

Objectives: To ascertain if aural syringing is a one size ts all solution for aural foreign body removal in a rural setting Methods: A Record based descriptive study was looked at paediatric and adult patients with Aural FB (foreign bodies) who visited ER (Emergency) and ENT-OPD (Out Patient Department) of a single institution between January 2022 and December 2022.The Diagnosis of Aural foreign bodies was based on personal history and Otoscopic ndings. Patient characteristics, foreign body type, removal attempts and complications were evaluated with respect to clinical setting and patient outcome. The Data was obtained from the records. Results: 86 patients were brought to the emergency department and ENT-OPD over a 12-month period with foreign bodies of the EAC (External Auditory Canal). Otolaryngologists used otoscope and standard metallic aural syringe as their mainstay of management. Analysis of ER and OPD cases revealed Inorganic aural foreign bodies were 65.11% and 34.88% were Organic foreign bodies. Unilateral Purulent Aural Discharge was in 46.51% (40) patients, pain in 17.44% (15), Ear Bleeding in 8.13% (7), conductive hearing loss and tinnitus was 10.46% (9) and itching in 4.65% (4). Duration of Symptoms was <1 week in 65.11% (56) cases ,1-2 weeks in 22.09% (19) and 2-4 weeks in 12.79% (11) cases. Successful removal of foreign bodies from ear by only applying aural syringing was achieved in 91.86% of cases, and usage of other methods of aural foreign body removal Forceps, Hook and Suction in 5.8% and foreign body removal under GA was 2.32% were recorded Conclusion Aural foreign bodies were commonly seen in paediatric population. Patients commonly present to the ER and OPD for removal of EAC foreign bodies. The common inorganic aural foreign bodies were cotton tip, stone and eraser whereas y, lice and bee were the organic FB. The most common symptoms and complications of aural FBs, were unilateral purulent discharge followed by pain, ear Bleeding, Tympanic membrane perforation, external meatus laceration, chronic otitis media and facial Nerve paralysis. The most common procedures used were Syringing followed by Forceps, hook and suction. It is observed that aural syringing performed by the trained hands of an otolaryngologist is a very effective method and can almost be described as a one size ts all solution for managing foreign bodies in EAC with some notable exceptions

Saving time when preparing intravenous antibiotics.

Preparation of intravenous antibiotic doses takes up a significant amount of nurse time and exposes nurses to the risk of needlestick injury. The use of the Ecoflac® Connect needle-free connector could streamline preparation, reducing the time taken as well as eliminating needlestick injury risk. Because Ecoflac Connect is a closed system, it also minimises the risk of microbial contamination. This study showed that it took 83 experienced nurses 73.6 (SD 25.0) seconds to prepare an amoxicillin injection using the Ecoflac Connect needle-free connector compared with 110.0 (SD 34.6) seconds using the standard needle and syringe method, saving 36 seconds per dose on average, reducing the time taken by one-third. Based on recent government figures, the saving in nurse time would equate to 200-300 full-time nurses in England, equivalent to £6.15 million-£9.23 million a year. Additional savings would accrue from the prevention of needlestick injuries. Where wards are understaffed, this time saving could be critical, increasing time for care.

Autologous fat grafting in patients with volume restoration, soft tissues and skin defects correction

Objective. To analyze the results of fat grafting in volume restoration, soft tissues and skin defects correction.
 Materials and methods. Autologous fat grafting was performed for aesthetic soft tissues correction in 30 women, as well as in 3 patients with long-term non-healing trophic ulcers to obtain a regenerative effect. Subcutaneous fat aspiration was implemented using standard liposuction techniques, water jet, mechanical and syringe.
 Results. The volume of fat graft varied depending on the area requiring correction, and averaged 90 (33195) ml. The areas, most often subjected to fat grafting, were the mammary glands 10 (33 %), shins 8 (27 %), buttocks 5 (17 %), hands 2 (7 %), lips and nasolabial region 2 (7 %), the outer surface of the thigh 1 (3 %). Despite partial decrease of fat graft volume in the postoperative period, all patients were satisfied with the results; no complications of the procedure were noted. The preparation of fat graft for the correction of trophic defects included its washing with saline and filtering with 1.4 and 1.2 mm anaerobic fat transfers; the fat was grafted through a 2 mm cannula into the subcutaneous tissue directly under and around the ulcerative defects. It improved the regeneration of the epithelium around the trophic ulcers and reduced their size.
 Conclusions. Thus, the efficiency and safety of using the technique of autologous fat grafting for volumizing and regenerative purposes has been clinically confirmed.

Investigating the use of non-loss of resistance syringes for epidural insertion: experience on a mannequin

IntroductionThe Obstetric Anaesthetists’ Association has released a statement outlining the disruption to supply of the Portex® Loss of Resistance Syringe (Smiths Medical, UK) which is commonly used for epidural insertion within our Trust. We sought to investigate the use of standard available syringes for epidural insertion and whether tactile feedback when getting loss of resistance was similar. MethodsUsing an epidural trainer model, we asked anaesthetists regularly working in the maternity unit to trial three alternative syringes (10 mL BD Emerald, 10 mL BD syringe from our epidural packs, and 20 mL BD Plastipak) (Becton Dickinson U.K. Limited, UK) and to complete a qualitative questionnaire about their experience. ResultsResponses from 16 anaesthetists, including individuals with a range of obstetric anaesthetic experience who regularly provide obstetric anaesthesia, were collected. With the BD Emerald 10 mL syringe, 81% considered there was no difference or only a slight difference when feeling for loss of resistance. For the BD 10 mL syringe, this figure was 75%. With the 20 mL syringe 66% reported either a reasonable or marked difference in tactile feel. The most popular syringe was the 10 mL BD Emerald syringe. ConclusionUsing an epidural training mannequin, this study suggests that it is still possible to elicit clear loss of resistance using alternative syringes. Of the three alternative syringes commonly available in our organisation, the BD Emerald 10 mL syringe was the most popular.

Full Recovery after Multiple Treatments with Injectable Ice Slurry.

BackgroundCryoneurolysis uses tissue cooling as an opioid-sparing, long-lasting treatment for peripheral nerve pain. A nerve-selective method for cryoneurolysis by local injection of ice-slurry was developed to allow cryoneurolysis to be performed with a standard needle and syringe, similar to peripheral nerve blocks. Since the treatment of patients with chronic pain may require repeated injections, we investigated the safety and tolerance of repeated treatments in a rat model.MethodsThree repeated ice-slurry treatments, given 6 weeks apart were performed around the rat sciatic nerve. Nerve and surrounding tissues were collected up to 4 months after the third treatment for analysis. Coherent anti-Stokes Raman scattering (CARS) microscopy was used to study effects on myelin sheaths and axon structure. Immunofluorescence (IF) staining was used to study effects on axon density. Hematoxylin and Eosin (H&E) staining was used to examine histologic effects on sciatic nerve and surrounding tissue.ResultsHistologic and CARS image analysis of nerve tissue collected months after three injections demonstrated recovery of nerve structure, myelin organization and axon density to baseline levels, without any residual inflammation, scarring or neuroma formation. No inflammation or scarring was detected in surrounding skin and muscle tissues.ConclusionRepeated ice-slurry injections cause temporary, nerve-selective and reversible changes in the peripheral nerve. There was no histologic damage to surrounding skin and muscle tissues. Repeated treatments with injectable ice-slurry for cryoneurolysis appear to be safe and well tolerated. Clinical studies for patients with chronic pain are warranted.

Polypseudorotaxane hydrogel based on Tween 80 and α-cyclodextrin for sustained delivery of low molecular weight heparin

Low molecular weight heparin (LMWH), an anionic polysaccharide, has been widely used as a clinical anticoagulant. However, repeated subcutaneous injection is sometimes required due to its short half-life. To reduce the dosing frequency, the injectable polypseudorotaxane hydrogel was fabricated by inclusion complexation formation between Tween 80 and α-Cyclodextrin (αCD) for sustained release of LMWH. The physicochemical properties of such hydrogel were characterized by SEM, XRD, DSC, and FTIR. This hydrogel showed shear-thinning and thixotropic behavior and was easily injected through standard syringe needles. The gelation time, mechanical strength, shear viscosity, in vitro drug release rate, in vitro hydrogel dissolution rate, and in vivo hydrogel retention could be tuned by αCD concentration in the hydrogel. In vivo safety evaluation indicated that the polypseudorotaxane hydrogel was biocompatible. Most importantly, this polypseudorotaxane hydrogel could sustain release of LMWH after subcutaneous injection.

Advances in Large Volume Subcutaneous Injections: A Pilot Tolerability Study of an Innovative Needle-Free Injection Platform.

Many medical conditions require chronic treatment with subcutaneous injectable biologics often exceeding 1.0 mL. However, subcutaneous administration of volumes of 2.0 mL or greater using a standard needle and syringe or auto-injector proves challenging, and patients often must administer two separate injections to achieve their full dose or endure injection times in excess of 10 s if using a mechanical autoinjector. In addition, needle-based injections often cause patient anxiety and discomfort. In this article, we describe an approach to meet these needs with a needle-free medication delivery device capable of rapidly delivering up to 2.0 mL with minimal discomfort. A pilot study was conducted with this needle-free injection system to evaluate the delivery of a 2.0 mL volume in human subjects. The results demonstrated that injections of up to 2.0 mL were well tolerated and often preferred over two separate 1.0 mL injections using the needle-free injection system.

Novel open-source 3D-printed eye mount (TEMPO) for the ophthalmology wet lab

ObjectiveProcuring an affordable eye mount that can stabilise a cadaveric eye and simulate a patient’s normal facial contours represents an ongoing challenge in the ophthalmology simulation wet lab, with notable...

Smart Syringe Vending Machines: Research Capabilities and Implications for Research Data Collection

Syringe vending machines (SVMs) are intended to supplement the standard syringe exchange programs to access hard-to-reach groups and to cover unserved geographical areas. This report describes how we adapted SVMs to deliver interventions and collect research data as part of a study of smart SVMs (SSVMs) in Tbilisi, Georgia. To create SSVMs, we upgraded commercial vending machines and developed a computer program to track and record interactions and to display messages related to study procedures. Preferred locations for SSVMs, product specifications, and the mode of operation were determined through formative input from people who inject drugs (PWID). SSVMs were installed near pharmacies and serve both the general population and PWID. The "hidden" interactive menu for the PWID prevention kits was displayed on the screen only when a special plastic card was used. The plastic cards were distributed to the clients of fixed syringe exchange programs and to their peers who were not in contact with harm-reduction services. Ten SSVMs were operational in Tbilisi as of March 2021, with more than 800 PWID using them on a regular basis. More than half of sterile equipment kits were distributed during weekends and night hours. Our innovative SSVM integrates features for intervention delivery and research data collection. It can be used for testing a variety of interventions beyond syringes (e.g., distribution of HIV/hepatitis C virus self-tests) and provides opportunities for serving various at-risk groups that might not otherwise access these products and services (e.g., men who have sex with men, commercial sex workers).

Utilization of High-pressure Suction for EBUS-TBNA Sampling in Suspected Lung Cancer.

Background:Sample adequacy for immediate molecular testing is paramount in lung cancer. To date, several endobronchial ultrasound with transbronchial needle aspiration (EBUS-TBNA) sampling setups have been evaluated, however, the utilization of high-pressure suction (HPS) has not yet been reported.The aim of this study was to evaluate the utilization of HPS onto the needle and its effect on sample volume and adequacy for molecular testing in patients with suspected lung cancer.Methods:We retrospectively analyzed 128 consecutive EBUS-TBNA performed for suspected lung cancer. This was confirmed in 109 patients. Other diagnoses confirmed in 12, and 7 referred for surgery. Sixty-three patients (89 targets) had HPS (May to September 2020), and compared with 46 (72 targets) who had standard vacuum syringe suction (October 2019 to March 2020). Several parameters and outcomes evaluated, such as number of needle passes, needle strokes, needle size, target size, positron emission tomography avidity, procedure time, blood content score, sample volume, adequacy for molecular testing, as well as baseline patient characteristics and complication rate.Results:There was no difference between the 2 groups in all baseline parameters and characteristics. In multivariable analysis, HPS was associated with significantly higher sample volume (11.2 vs. 9.1 mm3, P=0.036) and less additional procedures to achieve full molecular profiling (2/52 vs. 7/40, P=0.042), in necrotic targets of non−small cell lung cancer. Diagnostic yields were comparable.Conclusion:HPS appears to be simple, no-cost, and safe, promising higher sample volume compared with vacuum syringe suction, and also appears to be associated with higher success of full molecular testing with less additional procedures, in non−small cell lung cancer necrotic targets.

FleXert: A Soft, Actuatable Multiwell Plate Insert for Cell Culture under Stretch.

Porous multiwell plate inserts are widely used in biomedical research to study transport processes or to culture cells/tissues at the air-liquid interface. These inserts are made of rigid materials and used under static culture conditions, which are unrepresentative of biological microenvironments. Here, we present FleXert, a soft, actuatable cell culture insert that interfaces with six-well plates. It is made of polydimethylsiloxane (PDMS) and comprises a porous PDMS membrane as cell/tissue support. FleXerts can be pneumatically actuated using a standard syringe pump, imparting tensile strains of up to 30%. A wide range of actuation patterns can be achieved by varying the air pressure and pumping rate. Facile surface functionalization of FleXert's porous PDMS membrane with fibronectin enables adhesion of human dermal fibroblasts and strains developing on FleXert's membrane are successfully transduced to the cell layer. 3D tissue models, such as fibroblast-laden collagen gels, can also be anchored to PDMS following polydopamine coating. Furthermore, collagen-coated FleXert membranes support the establishment of a human skin model, demonstrating the material's excellent biocompatibility required for tissue engineering. In contrast to existing technologies, FleXerts do not require costly fabrication equipment or custom-built culture chambers, making them a versatile and low-cost solution for tissue engineering and biological barrier penetration studies under physiological strain. This paper is an extensive toolkit for multidisciplinary mechanobiology studies, including detailed instructions for a wide variety of methods such as device fabrication, theoretical modeling, cell culture, and image analysis techniques.

3D-Printing of zirconia dental prostheses

Introduction Yittria-stabilised-zirconia is a biomaterial widely employed in the production of dental prostheses through several traditional manufacturing and shaping processes (such as machining and surface grinding of a green or sintered block, gel-casting and injection moulding) which carry relatively high labour, tooling, moulding and waste material costs. Additive manufacturing 3D-printing processes, such as robocasting, enable the quick production of customised and intricate parts without the need for costly milling tools and moulds [1,2]. In this work, the robocasting process was employed in the production of zirconia parts using a layer-by-layer deposition strategy of a dispersed ceramic powder slurry through a numerically controlled extruder and nozzle. The highest possible solid content allowing for proper extrusion through a fine nozzle was determined for a plain, inexpensive water-based slurry of zirconia powders and dispersing agent. Materials and methods A commercial open-source 3D printer was modified to use a standard micrometric syringe and needle as an extruder Figure 1. An initial batch of 80 wt.% solid zirconia powder slurry was produced using a predetermined optimal CE64 dispersant ratio and equal portions were subsequently condensed through air-drying at 50 °C until an 82, 84, 86, 88 or 90 wt.% solid content ratio was reached. Each slurry was then used for the robocasting of zirconia cuboid samples, which were air-dried for 48 h at 50 °C and sintered at 1500 °C for 2 h. Sintered sample densities were measured using the Archimedes method and the polished base sample surfaces were characterised through microscopy analysis, hardness and toughness tests. The slurry yielding the best results was, thus selected for the production of a sintered tooth prototype using the same sample extrusion speeds, nozzle travel speeds and diameter (0.45 mm). Figure 1. Visual comparison of green samples robocasted from printable pastes. Results The best sample print quality was attained using 88 wt.% solid content slurries, which resulted in minimal microscopic sintering defects and no extrusion faults due to transient clogging of the extrusion nozzle, thus reaching a sintered density 97% that of theoretical. A full-size tooth prototype was successfully fabricated using the 88 wt.% solid content slurries Figure 2. Discussion and conclusions: The 88 wt.% solid content slurry showed increased viscosity, consistently raising extrusion pressure and shear stresses which likely broke-up any soft agglomerates, thus avoiding temporary nozzle clogging and the formation of agglomerate-related sintering defects. The 90 wt.% slurry showed near-dilatant behaviour, possibly possessing harder agglomerates. Thus, sintered sample parts with 97% theoretical density were realised from an 88 wt.% plain water-based slurry with no binders or plasticisers that would otherwise require an additional pre-sintering burnout stage and likely generate sintering defects. Figure 2. Post-sintering public domain molar tooth prototype printed using the using the 88 wt.% solid slurry next to an unrelated extracted tooth for comparison. The sliced 3D prototype tooth model used is shown in the rightmost picture.

Utility of low-cost, miniaturized peristaltic and Venturi pumps in droplet microfluidics

Many laboratory applications utilizing droplet microfluidics rely on precision syringe pumps for flow generation. In this study, the use of an open-source peristaltic pump primarily composed of 3D printed parts and a low-cost commercial Venturi pump are explored for their use as an alternative to syringe pumps for droplet microfluidics. Both devices provided stable flow (<2% RSD) over a range of 1–7 μL/min and high reproducibility in signal intensity at a droplet generation rate around 0.25 Hz (<3% RSD), which are comparable in performance to similar measurements on standard syringe pumps. As a novel flow generation source for microfluidic applications, the use of the miniaturized Venturi pump was also applied to droplet signal monitoring studies used to measure changes in concentration over time, with average signal reproducibility <4% RSD for both single-stream fluorometric and reagent addition colorimetric applications. These low-cost flow methods provide stable flow sufficient for common droplet microfluidic approaches and can be implemented in a wide variety of simple, and potentially portable, analytical measurement devices.