Outer Needle Research Articles

A novel semi-flexible coaxial nozzle based on fluid dynamics effects and its self-centering performance study

Coaxial nozzles are widely used to produce fibers with core–shell structures. However, conventional coaxial nozzles cannot adjust the coaxiality of the inner and outer needles in real-time during the fiber production process, resulting in uneven fiber wall thickness and poor quality. Therefore, we proposed an innovative semi-flexible coaxial nozzle with a dynamic self-centering function. This new design addresses the challenge of ensuring the coaxiality of the inner and outer needles of the coaxial nozzle. First, based on the principles of fluid dynamics and fluid–structure interaction, a self-centering model for a coaxial nozzle is established. Second, the influence of external fluid velocity and inner needle elastic modulus on the centering time and coaxiality error is analyzed by finite element simulation. Finally, the self-centering performance of the coaxial nozzle is verified by observing the coaxial extrusion process online and measuring the wall thickness of the formed hollow fiber. The results showed that the coaxiality error increased with the increase of Young’s modulus E and decreased with the increase of flow velocity. The centering time required for the inner needle to achieve force balance decreases with the increase of Young's modulus (E\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E$$\\end{document}) and fluid velocity (vf\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${v}_{f}$$\\end{document}). The nozzle exhibits significant self-centering performance, dynamically reducing the initial coaxiality error from 380 to 60 μm within 26 s. Additionally, it can mitigate the coaxiality error caused by manufacturing and assembly precision, effectively controlling them within 8 μm. Our research provides valuable references and solutions for addressing issues such as uneven fiber wall thickness caused by coaxiality errors.

Needle-in-needle electrochemical sensor for in-vivo monitoring of anticancer drug etoposide

Therapeutic drug monitoring (TDM) serves as a potent tool for adjusting drug concentration within a reasonable range. However, continuous monitoring of anticancer drugs in-vivo presents a significant challenge. Herein, we propose a needle-in-needle electrochemical sensor based on an acupuncture needle electrode, capable of monitoring the anticancer drug etoposide in the peritoneal cavity of living rats. The acupuncture needle was modified with Au nanoparticles and etoposide-templated molecularly imprinted polymer (MIP), resulting in high sensitivity and selectivity in the electrochemical detection of etoposide. The modified acupuncture needle (0.16 mm diameter) was anchored inside a syringe needle (1.40 mm diameter), allowing the outer syringe needle to protect the modified materials of the inner acupuncture needle during skin piercing. Due to the unique needle-in-needle design, high stability was obtained during in-vivo etoposide monitoring. Connecting to a smartphone-controlled portable electrochemical workstation, the needle-in-needle sensor offers great convenience in point-of-care TDM. Moreover, the electrode materials on the acupuncture needle were carefully characterized and optimized. Under the optimized conditions, low detection limits and wide linear range were achieved. This work provides new insights into acupuncture needle electrochemical sensors and further expands the feasibility for real-time and in-vivo detection.

Smaller Iatrogenic Defects Created by Inside-Out Compared With All-Inside Meniscus Repair Devices in Human Cadaveric Model

(1) To investigate the pattern and diameter of the iatrogenic defect that meniscal repair devices impose on meniscal tissue and (2) to determine whether repair-induced defect patterns or diameters differ across devices. Sixty-one fresh frozen human cadaveric menisci were used (n= 9; eliminated). All-inside devices (n= 9) included ULTRA FAST-FIX, FAST-FIX 360, Depuy Mitek 0° and 12° TRUESPAN, ConMed Sequent, Zimmer Biomet JuggerStitch, Stryker IvyAIR, Arthrex FiberStitch and Meniscal Cinch II. Inside-out needles (n= 4) included ConMed HiFi, Depuy Mitek ORTHOCORD, Arthrex-2-0 FiberWire, and Stryker SharpShooter. Following India Ink staining, implant devices were inserted into cadaveric menisci. Samples were fixed in formalin solution and imaged with a high-resolution camera. Defects were classified by qualitative evaluation. Defect and needle diameter were quantified with software assistance. Statistical analysis was performed using analysis of variance testing. We analyzed 644 iatrogenic defects with mean defect diameter of 1.96 mm (standard deviation 0.86). For all-inside devices, defect patterns (n= 436) were 15.6% linear, 38.1% semilunar, 46.3% stellate, while inside-out devices (n= 208) were 95.7% stellate, 4.3% linear, and 0.0% semilunar. All-inside devices had mean defect diameter of 2.46 mm, while inside-out meniscus needles had mean 0.90 mm defect diameter (P < .001). FasT-FIX 360, ULTRA-FAST-FIX, and Arthrex Meniscal Cinch II induced smaller diameter defects than other all-inside devices (F= 20.2, P < .05). Strong positive correlation was found comparing outer needle diameter and mean defect diameters across all devices (R2= 0.9447). Needles utilized in meniscal implant systems produce the following basic defect patterns: stellate (62.3%), semilunar (25.8%), and linear (11.9%). A strong positive correlation was found between mean defect size and outer needle diameter across all devices. Inside-out double-armed flexible needles produced significantly smaller defects than all-inside devices. Of the all-inside devices, ULTRA FAST-FIX, FAST-FIX 360, and Arthrex Meniscal Cinch II produced smaller defects on average. While the true clinical impact of these findings cannot be drawn from the present study, this investigation provides necessary context to better understand reported similarities and differences in healing rates and outcomes between inside-out and all-inside repair techniques.

The growth simulation of pine-needle like structure with diffusion-limited aggregation and oriented attachment.

A growth model combined with diffusion-limited aggregation (DLA) and oriented attachment (OA) is developed for deducing quantitative understanding of the growth process of pine-needle like structures. We define the completely random parameters for describing the realistic Brownian motion in DLA. The results indicate that the cluster by DLA changes from random branches to regular needles by the introduction of OA. And the cluster of DLA and OA has a fractal dimensionality of about 1.0 during the whole growth process. The maximum length of needels (Lmax) depends on the number of particles (Np). They satisfy the relation Lmax = aNpb (a and b are constant) over the whole range. The model has also been used to describe the formation of needles on a line, plane and sphere. The growth of needles has obvious steric hindrance from the outer needles. In particular, only one needle grows in the later period in the plane.

Distribution and behaviour of naturally occurring radionuclides within a Scots pine forest grown on a CaF2 waste deposit related to the Belgian phosphate industry

The distribution and behaviour of naturally occurring radionuclides within a vegetated part of a CaF2 sludge heap from the Belgian phosphate industry was studied. A Scots pine forest plot was selected as study area. Trees were approximately 20 years old and showed a disturbed health state. Seasonal sampling campaigns of soil, roots, wood, inner and outer bark, needles and twigs gave insight on 238U, 226Ra, 210Pb and 210Po transfer and distribution between pine tree compartments. Soil samples were analysed for their texture, total organic and inorganic carbon, field capacity, pH and radionuclide content. Solid-liquid distribution coefficients (Kd) were experimentally determined for 238U, 226Ra (using Ba as analogue) and 210Pb based on adsorption-desorption batch tests.Results indicated higher 238U, 232Th, 226Ra, 210Pb and 210Po activity concentrations in the deeper soil layers while the first 20 cm contained less radionuclides but had a higher level of organic carbon. Additionally, results indicated no seasonal changes in the 238U:226Ra ratio in the soil while the 226Ra:210Pb ratio was significantly higher in spring compared to winter in the 20–60 cm soil layer. Pine tree roots served as natural translocation barrier for all radionuclides with high retention in the roots and low translocation to the above ground tree compartments. When considering the above ground compartments, 210Pb and 210Po were mostly present in the bark, needles and twigs. Furthermore, 238U and its progeny were highly accumulated in mosses. These results allowed us to establish more realistic soil-to-plant transfer factors. In addition, experimentally mimicking pore water acidification in the root zone resulted in lower 238U and 210Pb Kd values compared to using a standard CaCl2 solution.This study provides an integrated radioecological picture of knowledge and site specific data needed to study the long-term influence of vegetation on radionuclide dispersion in forest ecosystems.

Minimally invasive and inexpensive percutaneous abscess drainage using an indwelling needle cannula

PurposeAbscess is still a formidable disease and requires adequate drainage. Moreover, drainage in the head and neck area needs cosmetic care, especially in the pediatric population. In this report, we introduce our method of percutaneous abscess drainage using an indwelling needle cannula.Patients and methodsTen pediatric and five adult patients with cervical and/or facial abscess treated with this drainage method were retrospectively reviewed. Using an indwelling needle cannula (18-14 G Surflow®, Terumo, Tokyo, Japan), abscesses were penetrated under ultrasonic examination. Once purulent retention was identified, the inner metal needle was removed and the outer elastic needle was left and fixed. The outer needle was connected to the tube for continuous suction drainage for large abscess.ResultsThe primary diseases of these abscesses were cervical abscess of dental origin (5), purulent lymphadenitis (3), pyriform sinus fistula (2) and subperiosteal abscess due to mastoiditis (2), circumorbital cellulitis (1), infection of Warthin's tumor (1), and unknown origin (1). The median (range) duration of drainage was 4 days (3–9 days). Abscesses were successfully treated, and no patients required additional incision for abscess drainage. No apparent scars after drainage were observed.ConclusionThis technique resembles the usual venous placement of an indwelling needle cannula and is thought to be familiar to physicians. Although simple and inexpensive, this drainage is safe, effective, and minimally invasive for the treatment of abscess.

Controllability Over Wall Thickness of Tubular Structures and Encapsulation During Co-Axial Extrusion of a Thermal-Crosslinking Hydrogel

AbstractTubular structures of the hydrogel are used in a variety of applications such as delivering nutrient supplies for 3D cell culturing. The wall thickness of the tube determines the delivery rate. In this study, we used the coaxial extrusion process to fabricate tubular structures with varying wall thicknesses using a thermal-crosslinking hydrogel, gellan gum (GG). The objectives of this study are to investigate the thermal extrusion process of GG to form tubular structures, the range of achievable wall thickness, and a possibility to form tubular structures with closed ends to encapsulate fluid or drug inside the tube. The wall thickness is controlled by changing the relative flow velocity of the inner needle (phosphate-buffered saline, PBS) to the outer needle, while keeping the velocity of outer needles (GG) constant. Two pairs of coaxial needles were used which are 18-12 gauge (G) and 20-12G. The controllable wall thickness ranges from 0.618 mm (100% relative velocity) to 0.499 mm (250%) for 18-12G and from 0.77 mm (80%) to 0.69 (200%) for 20-12G. Encapsulation is possible in a smaller range of flow velocities in both needle combinations. A finite element model was developed to estimate the temperature distribution and the wall thickness. The model is found to be accurate. The dynamic viscosity of GG determines the pressure equilibrium and the range of achievable wall thickness. Changing the inner needle size or the flow velocity both affect the heat exchange and thus the temperature-dependent dynamic viscosity.

SYSTEMIC AIR EMBOLISM AFTER PERCUTANEOUS CT-GUIDED LUNG BIOPSY

SESSION TITLE: Global Case Report Posters SESSION TYPE: Global Case Reports PRESENTED ON: 10/23/2019 09:45 AM - 10:45 AM INTRODUCTION: Computed-tomography (CT) guided transthoracic needle biopsy (TTNB) is widely performed to establish a histological diagnosis of peripheral lung tumors. Systemic air embolism is described as a rare complication. CASE PRESENTATION: In a 70-year-old man with systemic arterial hypertension and benign prostatic hypertrophy a peripheral pulmonary consolidation in the left upper lobe and multiple brain nodules were detected after an acute episode of epilepsy. As a primary lung tumor was suspected, he underwent a total body positron emission tomography-CT scan, showing pathological glucose uptake in the left lung lesion (Figure 1) and metastatic involvement of mediastinal lymph nodes, adrenal glands and vertebral bodies. His coagulation profile, hemoglobin and platelets levels were normal, so a bronchoscopy with transbronchial lung biopsy under fluoroscopy was set. The histological analysis showed bronchial inflammatory cells, so the patient underwent a CT-guided TTNB. Under local anesthesia, two bioptic samples were collected using the 18-gauge outer coaxial needle by an expert interventional radiologist (Figure 2A). During the procedure the onset of air embolism in both heart ventricles, main pulmonary artery and ascending aorta was immediately detected on CT scans (Figure 2B). A layer of ipsilateral pneumothorax (maximum thickness 12 mm) together with chest wall subcutaneous emphysema were present. The patient complained about general malaise with signs of hypotension and desaturation. No electrocardiographic alterations were recorded. After he was administered 100% oxygen through a mask and hydrated, his clinical conditions rapidly improved. Two hours later a chest and brain CT scans were repeated. While cardiac, aortic and pulmonary artery air embolisms were solved, the pneumothorax layer increased (20 mm) (Figure 3). No ischemic lesions were detected in brain CT scans. The patient was maintained on close monitoring and after four days the pneumothorax was no longer radiologically detectable. An invasive lung adenocarcinoma was diagnosed and the patient was referred to the Oncology Department. DISCUSSION: Systemic air embolism is described in 0.02-0.07% of TTNB (1). Direct exposure of pulmonary vein to air through the needle, bronchovenus fistula formation and air penetration from the pulmonary arterial circulation to the pulmonary vein are all possible pathogenic mechanisms (2). Possible prevention strategies include avoiding coughing and straining during the procedure and ventilation with positive pressure (3). No specific treatment has established yet other than supplying 100% oxygen and hyperbaric chamber. The patient has to be strictly monitored because potential life-threatening complications may rise and the repetition of a chest-brain CT scan may be urgently needed (3). CONCLUSIONS: Even if uncommon, systemic air embolism after TTBN must be always considered and rapidly handled. Reference #1: Sinner WN. Complications of percutaneous transthoracic needle aspiration biopsy. Acta Radiol. 1976;17:813-28 Reference #2: Mokhlesi B, Ansaarie I et al. Coronary artery air embolism complicating CT.guided transthoracic needle biopsy of the lung. Chest. 2002;121:993-996 Reference #3: Hare SS, Gupta ATC et al. Systemic arterial air embolism after percutaneous lung biopsy. Clin Radiol. 2011;66:589-596. DISCLOSURES: No relevant relationships by Paolo Ceruti, source=Web Response No relevant relationships by SARA ALESSANDRA LONNI, source=Web Response

SUN-336 A NEW KIDNEY BIOPSY DEVICE PROTOTYPE WITH HAEMOSTATIC FUNCTION

Native kidney biopsy is currently the gold standard to diagnose kidney disease. However, it is not routinely performed because of a 5% risk of severe bleeding, due to inadvertent puncture of small and micro renal vasculature. This could lead to complications such as requirement for blood transfusion, embolization, partial nephrectomy and death. We aimed to design and develop a radical new kidney biopsy device with concurrent haemostatic function to plug the biopsy tract immediately following needle withdrawal. We had investigated different engineering specifications and models of the biopsy device, such as needle dimensions and geometry, friction between needle and tissue, needle stiffness, spring constant, volume of haemostatic agent, volume of tissue collecting site and velocity of the outer needle. We developed a prototype and then evaluated it on various simulation models. We used commercially available haemostatic agent AristaTM AH (C.R. Bard, Inc. USA) for the testing for the biopsy device. We developed three conceptual biopsy device designs (A: rotatable inner needle, B: double inner needles and C: separate drug channel). The design A (Figure 1) was selected into the final prototype development. In this design, the biopsy instrument consists of an outer needle, inner needle, and a push rod. There is a semi-cylindrical opening near the distal of the outer needle, which facilitates entry of tissue after insertion into targeted position. The inner needle is coaxially placed in the outer needle. The end of the inner needle is a cavity, which is used to store the tissue sample. Relative motion of the outer needle and the inner needle form an end-cut. When sampling is completed, an opening on the inner tube can be exposed by rotating the inner needle 180 degrees, and haemostatic agents stored in the inner needle released by pushing the rod. Figure 1: Design A: The delivery mechanism of the haemostatic agent employs a rotatable inner needle. A prototype (Figure 2) had been developed, and verification tests with regards to the tensile force of the spring and testing on various simulation models had been carried out. The ability to extract sample and release haemostatic agent was 85% and 100% in ex vivo porcine liver, and 100% and 80% in ex vivo porcine kidney. Figure 2: Prototype of the biopsy device. We had designed and developed a new kidney biopsy device prototype with the ability to plug the biopsy tract immediately with haemostatic agent following biopsy. We have filled the patent (application no: 10201801487V) with the Intellectual Property Office of Singapore. Further testing in live animal would be carried out to improve the design of the biopsy device before conducting any human studies.

Controlling the Composition, Morphology, Porosity, and Surface Chemistry of Lignin-Based Electrospun Carbon Materials

Electrospinning is a suitable top-down technique for the preparation of polymeric fibers using high voltage electrical fields and solutions of the selected polymer of adequate viscosity and conductivity. The versatility of electrospinning allows accurate control of the morphology and composition of the fibers by a wide combination of operating conditions and small modifications of the spinneret and collector. Alcell lignin, which is extracted from lignocellulosic biomass using organic solvents through Organosolv process, is readily solved in ethanol, producing a solution that matches the requirements of the electrospinning process. This review summarizes the vast collection of carbon materials that can be obtained by processing lignin using electrohydrodynamic forces. The coaxial and triaxial electrospinning setups allow for obtaining fibers with two or more components hierchically arranged, the use of these configurations along with a carefully setting of the operating conditions (distance between needle and collector, voltage, flow rate,…) and the solution properties (conductivity, viscosity,…) facilitates the conformation of lignin into spheres, beaded fibers, straight fibers and fused meshes. All these morphologies can be implemented with solid or hollow bodies (i.e. enabling the production of tubes and hollow spheres) by using a sacrificial templating agent. Phosphoric acid can also be added in small amounts to the lignin solution, shortening the thermostabilization time of the fibers. The porosity of the phosphorus containing carbon fibers can be modified in the last stage of the preparation of carbon fibers by controlled gasification process, owing to the extended oxidation resistance of the P-doped fibers. Fibrillar carbon catalysts can be also obtained by one-pot preparation method, only solving small quantities of metallic salts in the lignin solution. In addition, alumina and silica-coated lignin fibers were produced by feeding a partially gelated solution of the respective alkoxide through the outer needle of the spinneret. The coated fibers can be carbonized without thermostabilization step, decreasing considerably the preparation time. All these carbon materials were successfully tested in different applications such as heterogeneous catalysis, energy storage and environmental protection, confirming that electrospinning is a powerful tool for maximizing the value of lignin as carbon precursor.

Repeated Percutaneous Treatment of Massive Hepatic Cystic Echinococcosis in a Child

Because of mostly asymptomatic cyst growth and often-neglected nonspecific low-grade symptoms, many cases of cystic echinococcosis (CE) caused by Echinococcus granulosus in the pediatric population are diagnosed at school age, in an advanced and even complicated stage. In 2003, after 5 months of intermittent dull upper-right abdominal pain and nausea, a 13-year-old boy was diagnosed with massive liver CE, with ∼20 round-shaped double-walled medium-sized infective cysts, which permeated the whole liver. Because of their wide distribution across the liver tissue and the risky superficial position of some cysts, liver transplantation emerged as the optimal therapeutic option. Despite being described as only an exceptionally used method for CE, we subjected our patient on 4 occasions to a radiofrequency energy thermoablation (RFT) procedure similar to the one used for malignant neoplasms. In total, 9 superficially situated cysts were initially treated with RFT by using a 14-gauge outer needle and a temperature of 70°C for 8 minutes per cyst, and the remaining cysts were treated with the puncture-aspiration-instillation-reaspiration procedure, along with albendazole (15 mg/kg per day) therapy, for a period of 20 months. After 2 years of follow-up, 4 residual small-sized semisolidified cysts were seen in the liver, and the patient showed no signs of relapse. Although not routinely used, RFT, along with puncture-aspiration-instillation-reaspiration and prolonged albendazole therapy, has shown good tolerability and long-term efficacy in the treatment of multiple infective CE, which could suggest the usefulness of the RFT method beyond salvage situations in pediatric patients.

Nanoscale coaxial focused electrohydrodynamic jet printing.

Controlled patterning of nanostructures at desired positions is of great importance for high-performance M/NEMS devices. Here, we demonstrate a high-resolution, high-speed and cost-effective fabrication method, named coaxial focused electrohydrodynamic jet printing, to print functional nanostructures. A coaxial needle was designed and developed; a functional ink and high viscosity liquid are applied in the inner and outer needle, respectively. Under optimised conditions, a stable coaxial jet is formed; then, the electrical shearing force and electrical field induce viscous shearing force and internal pressure that are jointly applied on the inner functional ink, focusing the inner jet on the nanoscale. Using this stable coaxial jet with a nano-jet inside it, nanostructures with highly aligned nanowire arrays, nano-freebeams and nano-cantilever beams down to the scale of 40 nm were directly printed. The needle size was 130 μm, and the ratio of the sizes of the needle and the printed structure was as high as 3250/1. This technique realizes the controllable printing of nanoscale structures with the use of a one hundred micrometer-sized needle. The printed PZT nanostructures exhibit pure perovskite structures and distinct piezoelectric responses.

Novel Double-Needle System That Can Prevent Intravascular Injection of Any Filler.

A new type of needle system combines 2 parts, an inner needle and an outer needle. The inner needle is used for filler injection and the outer needle acts as a guiding needle that can observe blood reflow when inserting into the vessel lumen during injection process. This new needle system can be used for all kinds of filler, providing real time monitoring for physician and preventing intravascular injection of any filler.

Encapsulation of rose hip seed oil into fibrous zein films for ambient and on demand food preservation via coaxial electrospinning

Several active encapsulation technologies using polymeric matrix systems for food preservation have been developed in the last decade. In this study, the microencapsulation of rose hip seed oil (REO) in to a zein prolamine (ZP) fiber matrix via the coaxial electrospinning technique is studied. The morphological features of core-sheath REO encapsulated ZP fibers were modulated through process parameters (e.g. active and polymer solution concentration, applied voltage and media flow rate). The ZP solution concentration (outer needle) was found to be critical for REO loading capacity (LC) and encapsulation efficiency (EE). The optimal LC and EE of REO in ZP matrix was 12.24% and 90.16%, respectively, and were achieved using a ZP concentration of 35 w/v%. Food packaging potential was evaluated using peeled and segmented fruits (bananas and cumquats). The findings demonstrate a facile packaging route to improve food sustainability and reduce waste.

Improving photoluminescence of poly(9‐vinylcarbazole)/4,7‐diphenyl‐1,10‐phenanthroline/tris‐(8‐hydroxyquinoline) aluminum fibers via coaxial electrospinning

ABSTRACTSolutions of poly(9‐vinylcarbazole)/4,7‐diphenyl‐1,10‐phenanthroline (PVK/Bphen) and poly(9‐vinylcarbazole)/tris‐(8‐hydroxyquinoline) aluminum (PVK/Alq3) were individually delivered either to the inner or the outer needle of a coaxial spinneret for electrospinning to prepare green luminescent PVK/Bphen/Alq3 composite fibers. The influence of both flow rate and applied voltage on the photoluminescence of the composite fibers was evaluated. Scanning electron microscopy showed ribbon‐like fibers with uneven surfaces and thickness of about 5 µm. Raman spectroscopy and fluorescence microscopy revealed that Bphen was homogenously dispersed in the PVK fibers; Alq3 was not. Photoluminescence shows strong evidence that there are marked conditions where emission of the co‐electrospun PVK/Bphen/Alq3 fibers significantly improved as compared with those produced by simple electrospinning. It is suggested that the enhanced dispersion of the Alq3 allowed a more efficient energy transfer from the PVK to the Alq3. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44019.

Steady cone-jet mode in compound-fluidic electro-flow focusing for fabricating multicompartment microcapsules

A compound-fluidic electro-flow focusing (CEFF) process is proposed to produce multicompartment microcapsules. The central device mainly consists of a needle assembly of two parallel inner needles and one outer needle mounted in a gas chamber with their tips facing a small orifice at the bottom of the chamber. As the outer and the inner fluids flow through the needle assembly, a high-speed gas stream elongates the liquid menisci in the vicinity of the orifice entrance. An electric field is further integrated into capillary flow focusing to promote the formation of steady cone-jet mode in a wide range of operation parameters. The multiphase liquid jet is broken up into droplets due to perturbation propagation along the jet surface. To estimate the diameter of the multiphase liquid jet as a function of process parameters, a modified scaling law is derived and experimentally validated. Microcapsules of around 100 μm with an alginate shell and multiple cores at a production rate of 103–105 per second are produced. Technical feasibility of stimulation triggered coalescence and drug release is demonstrated by benchtop experiments. The proposed CEFF process can be potentially used to encapsulate therapeutic agents and biological cargos for controlled micro-reaction and drug delivery.

Platform Technologies for Directly Reconstructing 3D Living Biomaterials.

Bio-electrospraying and cell electrospinning is explored for reconstructing living biomaterials for regenerative biology and medicine. The investigations carried out in this study demonstrate these approaches as platform biotechnologies for tissue reconstruction for repair, replacement, and rejuvenation of damaged and/or ageing tissues and/or organs.

Antibacterial Nanofibrous Mats Composed of Eudragit for pH-Dependent Dissolution

A pH-responsive nanofibrous mesh was prepared for the controlled release of antibiotics in response to pH changes. Eudragit EPO (EPO) and Eudragit L100 (L100) were injected through inner and outer needle and simultaneously electrospun through coaxial nozzles composed of inner and outer needles. Various amounts of EPO and L100 were coejected with tetracycline through the needle and simultaneously electrospun to the fibrous meshes. The mass erosion rates of the meshes at pH 6.0 gradually decreased as the amounts of EPO increased, whereas those at pH 2.0 showed negligible differences; these differences were confirmed by scanning electron microscopy and monitoring the dry weight changes. At pH 6.0, the fibrous structures of the meshes rapidly disappeared compared to those under acidic conditions because Eudragit L100 is localized to the shell of the nanofiber during the electrospinning process. Both the pH changes and the blend ratio of the two polymers significantly affected the tetracycline release; tetracycline was rapidly released from the meshes at pH 6.0, whereas the release rates were attenuated at pH 2.0. Tetracycline was released faster from the mesh at higher blend ratios of EPO for both pH values. The electrostatic interaction between EPO and L100 is expected to yield different release profiles of tetracycline. Consequently, higher amounts of encapsulated drugs were released from the mesh at neutral pH and successfully inhibited bacterial growth.

Micro/nano-encapsulation of a phase change material by coaxial electrospray method

This study is focused on the preparation of n-nonadecane-loaded calcium alginate capsules by coaxial electrospray technique. The solution and process parameters such as sodium alginate concentration, polymer feeding rate, needle gauge, needle length, needle-to-collector distance, and stirring speed were optimized through Taguchi method. These parameters were selected as variables, and three levels of them were introduced into L27 orthogonal arrays. Taguchi’s signal-to-noise ratio and analysis of variance were used to minimize the response and find the effect of control factors on it, respectively. The setup of the two-axial nozzle and feed rates of core/shell solutions were studied, as well. Optical microscopy, scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy were used for characterization of the capsules. The results showed that the sodium alginate concentration and the needle gauge are important factors for capsulated alginate material. The optical microscope images and the FTIR spectra confirmed that the alginate shell successfully fabricated the n-nonadecane materials. SEM analysis showed that at the optimal conditions, micro- and nano-capsules were prepared with nearly spherical shape. The results showed that when the inner needle tip was displaced 0.5 mm ahead of the tip of the outer needle, the envelopment of the core polymer was better accomplished by the outer polymer.

Human factors engineering and design validation for the redesigned follitropin alfa pen injection device

Objectives: To demonstrate, using human factors engineering (HFE), that a redesigned, pre-filled, ready-to-use, pre-asembled follitropin alfa pen can be used to administer prescribed follitropin alfa doses safely and accurately.Methods: A failure modes and effects analysis identified hazards and harms potentially caused by use errors; risk-control measures were implemented to ensure acceptable device use risk management. Participants were women with infertility, their significant others, and fertility nurse (FN) professionals. Preliminary testing included ‘Instructions for Use’ (IFU) and pre-validation studies. Validation studies used simulated injections in a representative use environment; participants received prior training on pen use.Results: User performance in preliminary testing led to IFU revisions and a change to outer needle cap design to mitigate needle stick potential. In the first validation study (49 users, 343 simulated injections), in the FN group, one observed critical use error resulted in a device design modification and another in an IFU change. A second validation study tested the mitigation strategies; previously reported use errors were not repeated.Conclusions: Through an iterative process involving a series of studies, modifications were made to the pen design and IFU. Simulated-use testing demonstrated that the redesigned pen can be used to administer follitropin alfa effectively and safely.