Fabrication of a microfluidic device for the compartmentalization of neuron soma and axons

In this video, we demonstrate the technique of soft lithography with polydimethyl siloxane (PDMS) which we use to fabricate a microfluidic device for culturing neurons. Previously, a silicon wafer was patterned with the design for the neuron microfluidic device using SU-8 and photolithography to create a master mold, or what we simply refer to as a "master". Next, we pour the silicon polymer PDMS on top of the master which is then cured by heating the PDMS to 80 degrees C for 1 hour. The PDMS forms a negative mold of the device. The PDMS is then carefully cut and lifted away from the master. Holes are punched where the reservoirs will be and the excess PDMS trimmed away from the device. Nitrogen is used to blow away any excess debris from the device. At this point the devices are now ready for use and can either bonded to corning No. 1 cover glass with a plasma sterilizer/cleaner or can be reversibly bound to the cover glass by simply placing the device on top of the cover glass. The reversible bonding of the device to glass is covered in a separate video and requires first that the device be sterilized either with 70% ethanol or by autoclaving. Plasma treating sterilizes the devices so no further treatment is necessary. It is, however, important, when plasma-treating the devices, to add liquid to the devices within 10 minutes of the plasma treatment while the surfaces are still hydrophilic. Waiting longer than 10 minutes to add liquid to the device makes it difficult for the liquid to enter the device. The neuron devices are typically plasma-bound to cover glass and 0.5 mg/ml poly-L-lysine (PLL) in pH 8.5 borate buffer is immediately added to the device. After a minimum of 3 hours incubating with PLL, the devices are washed with dH2O water a minimum of 3 times with at least 15 minutes between each wash. Next, the water is removed and fresh media is added to the device. At this point the device is ready for use. It is important to remember at this point to never remove all the media from the device. Always leave media in the main channel.     

Transcatheter aortic valve replacement: impact of pre-procedural FEops HEARTguide assessment on device size selection in borderline annulus size cases

ObjectivesThe aim of this study is to evaluate device size selection in patients within the borderline annulus size range undergoing transcatheter aortic valve replacement (TAVR) and to assess if pre-procedural patient-specific computer simulation will lead to the selection of a different device size than standard of care.BackgroundIn TAVR, appropriate device sizing is imperative. In borderline annulus size cases no standardised technique for tailored device size selection is currently available. Pre-procedural patient-specific computer simulation can be used, predicting the risk for paravalvular leakage (PVL) and need for permanent pacemaker implantation (PPI).MethodsIn this multicentre retrospective study, 140 patients in the borderline annulus size range were included. Hereafter, device size selection was left to the discretion of the operator. After TAVR, in 24 of the 140 patients, patient-specific computer simulation calculated the most appropriate device size expected to give the lowest risk for PVL and need for PPI. In these 24 patients, device size selection based on patient-specific computer simulation was compared with standard-of-care device size selection relying on a standardised matrix (Medtronic).ResultsIn a significant proportion of the 140 patients (26.4%) a different device size than recommended by the matrix was implanted. In 10 of the 24 patients (41.7%) in whom a computer simulation was performed, a different device size was recommended than by means of the matrix.ConclusionsDevice size selection in patients within the borderline annulus size range is still ambiguous. In these patients, patient-specific computer simulation is feasible and can contribute to a more tailored device size selection.     

Development of a Device in Detection of Glaucoma for Rural Eye Care Using Additive Manufacturing and TRIZ

Purpose: The main purpose of this study is to develop a device for the indicative measurement of intraocular pressure (IOP) of eyeball, a key cause for glaucoma. In early diagnosis and treatment of glaucoma accurate measurement of IOP is important. The methods and devices which are available for the measurement of IOP have their own limitations which cause discomfort to the patients during measurement and needs anesthesia. There is a dare need of a device for the measurement of intraocular pressure by making the contact of plunger with closed eyelid eliminating the need of anesthesia and expert ophthalmologist. Method: Additive manufacturing (AM) is an era of technical development and innovation. Developing a device for detecting glaucoma by using AM and TRIZ ‘The theory of inventive problem solving’ (A Collaborative approach) can overcome the disadvantages that classic tonometer have. The field of Ophthalmology will be experiencing a paradigm shift towards the use of collaborative approach of TRIZ with AM. The developed new device was tested on 40 patient’s eye at Government Hospital Bhandara, (M. S.), India. The results of new device were cross verified by expert clinicians using calibrated Schiotz’s tonometer and digital palpation technique. Result: The developed new device was tested on patient’s eye through eyelid and results were compared with calibrated Schiotz’s tonometer. The results from the new device were found in good agreement with results from Schiotz’s tonometer with the average error of 0.033 ± 0.18 (mean ± SD) mm of Hg and mean relative error was -0.0018 ±0.0096 (mean ± SD). Conclusion: There is a substantial need for early detection and diagnosis of glaucoma in rural and remote areas (worldwide). A new device for detection of glaucoma using AM and TRIZ was introduced in this paper and measurements by the new device were by currently well accepted Schiotz’s tonometer. The new device will help the medical practitioners in rural and remote areas for early detection of glaucoma.     

A versatile apparatus for performing anaerobic optical titrations with provision for multiple sampling of the reaction mixture.

An all-glass device sultable for the oxido-reductive titrations of air-sensitive compounds is deseribed. The device has a provision for monltoring the optical spectrum and for sampling the reaction mixture with direct transfers of the sample into electron-paramagnetic resonance sample tubes. The performance of the device is evaluated and an example of its use is given.     

A new airway device for small laboratory animals

There is a need for a device for improved management of the airway of small laboratory animals during general anaesthesia. This report introduces such a device, referred to here as the airway device (AD). The AD has some similarity to the laryngeal mask airway (LMA) developed for human patients, but the mask portion of the device is specifically designed for small laboratory animals. In addition, the device has an oesophageal extension and unlike the LMA does not have a cuff associated with the mask. This report also shares experience of tests of one prototype AD with six New Zealand white rabbits. The AD was used for administering isoflurane and its effectiveness was evaluated during conditions of spontaneous and controlled intermittent positive pressure ventilation. The results provide encouragement for further development of the AD for airway management of small laboratory animals.     

Development of head docking device for linac-based radiosurgery with a Neptun 10 PC linac

Stereotactic radiosurgery is a method for focused irradiation of intracranial lesions. Linac-based radiosurgery is currently performed by two techniques: couch mounted and pedestal mounted. In the first technique a device is required to affix the patient's head to the couch and neoreover to translate it accurately. Structure of such a device constructed by the authors plus acceptance test performed for evaluation is described in the article.A head docking device has been designed and constructed according to geometry of linac's couch and also desired functions. The device is cornpletely made from aluminum and consists of four major components: attachment bar, lower structure with four moveing accuracy mechanical stability and isocentric accuracy were assessed in the frame of acceptance test.Translating accuracy, mechanical stability and isocentric accuracy were found to be respectively: 1 mm, 1.64 mm and 3.2 mm with accuracy of 95%.According to AAPM report no. 54, a head docking device should translate head with an accuracy of 1 mm; this recommendation has been met. Moreover, we have demonstrated that the isocentric accuracy and mechanical stability of the device are sufficient that the device on confidently be used in stereotactic treatment.     

Nucleic acid purification using microfabricated silicon structures

A microfluidic device has been designed, fabricated and tested for its ability to purify bacteriophage lambda DNA and bacterial chromosomal DNA, a necessary prerequisite for its incorporation into a biosensor. This device consists of a microfabricated channel in which silica-coated pillars were etched to increase the surface area within the channel by 300-600%, when the etch depth is varied from 20 to 50 microm. DNA was selectively bound to these pillars in the presence of the chaotropic salt guanidinium isothiocyanate, followed by washing with ethanol and elution with low-ionic strength buffer. Positive pressure was used to move solutions through the device, removing the need for centrifugation steps. The binding capacity for DNA in the device was approximately 82 ng/cm2 and on average, 10% of the bound DNA could be purified and recovered in the first 50 microl of elution buffer. Additionally, the device removed approximately 87% of the protein from a cell lysate. Nucleic acids recovered from the device were efficiently amplified by the polymerase chain reaction suggesting the utility of these components in an integrated, DNA amplification-based biosensor. The miniaturized format of this purification device, along with its excellent purification characteristics make it an ideal component for nucleic acid-based biosensors, especially those in which nucleic acid amplification is a critical step.     

A self-powered constant infusion device for use in unrestrained rats

We developed a device that delivers fluid through a catheter at a constant rate and can be used in conscious animals to solve a variety of problems. For example, this device can be used for delivering drugs and maintaining intravascular catheter patency. The device provides infusions at low flows (1.0-1.5 ml/day), so that experimental agents may be administered with minimal volume loading of the rat. Arterial and venous catheter patency is maintained by infusion of heparinized saline through indwelling catheters attached to the device. The catheters exit from the rat in the intrascapular area and are routed through a protective spring to the device, which is suspended above the cage. The catheters may be attached to pressure transducers, blood may be sampled, and injections or infusions may be made without disturbing the rat. Because the device is self-contained, it can be suspended by a fluid-free swivel that rotates through 360 degrees, providing minimal restraint. The device has been used successfully to measure arterial and central venous blood pressures in two studies using rats.     

Non-plasma bonding of PDMS for inexpensive fabrication of microfluidic devices

In this video, we demonstrate how to use the neuron microfluidic device without plasma bonding. In some cases it may be desirable to reversibly bond devices to the Corning No. 1 cover glass. This could be due, perhaps, to a plasma cleaner not being available. In other instances, it may be desirable to remove the device from the glass after the culturing of neurons for certain types of microscopy or for immunostaining, though it is not necessary to remove the device for immunostaining since the neurons can be stained in the device. Some researchers, however, still prefer to remove the device. In this case, reversible bonding of the device to the cover glass makes that possible. There are some disadvantages to non-plasma bonding of the devices in that not as tight of a seal is formed. In some cases axons may grow under the grooves rather than through them. Also, because the glass and PDMS are hydrophobic, liquids do not readily enter the device making it necessary at times to force media and other reagents into the device. Liquids will enter the device via capillary action, but it takes significantly longer as compared to devices that have been plasma bonded. The plasma cleaner creates temporary hydrophilic charges on the glass and device that facilitate the flow of liquids through the device after bonding within seconds. For non-plasma bound devices, liquid flow through the devices takes several minutes. It is also important to note that the devices to be used with non-plasma bonding need to be sterilized first, whereas plasma treated devices do not need to be sterilized prior to use because the plasma cleaner will sterilize them.     

Development of a three-microneedle device for hypodermic drug delivery and clinical application

There is a potential use for intradermic or hypodermic drug delivery in skin surgery or aesthetic surgery. Hypodermic delivery with the use of a noninvasive device can be a more useful, reliable, and effective administration route to obtain higher compliance. The authors developed a microneedle device composed of three fine needles (three-microneedle device). The tip of each needle was fabricated with a bevel angle to release a drug broadly into the tissue in a horizontal fashion. In this study, the authors investigated the usefulness of this newly developed three-microneedle device for hypodermic liquid injection, focusing on the optimum insertion depth and the diffusion of injected materials to the tissue. The authors also assessed the efficacy of and patient satisfaction with three-microneedle device injections of botulinum toxin type A for wrinkle reduction in patients with glabellar rhytides. The three-microneedle device yielded consistent results in hypodermal diffusion. On India ink diffusion test and ultrasonographic imaging, three-microneedle device injection showed a broad diffusion in horizontal extension, as compared with usual 31-gauge needle injection. The efficiency and satisfaction of the patients receiving botulinum toxin type A with the three-microneedle device were highly rated. Three-microneedle device delivery enables accurate and broad diffusion of injected substances, thus reducing the total dose and/or injection number of drugs. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.     

The Impact of Device Polarity on the Performance of Polymer–Fullerene Solar Cells

Diketopyrrolopyrrole (DPP)‐conjugated polymers are a versatile class of semiconductors for application in organic solar cells because of their tunable optoelectronic properties. A record power conversion efficiency (PCE) of 9.4% was recently achieved for DPP polymers, but further improvements are required to reach true efficiency limits. Using five DPP polymers with different chemical structures and molecular weights, the device performance of polymer:fullerene solar cells is systematically optimized by considering device polarity, morphology, and light absorption. The polymer solubility is found to have a significant effect on the optimal device polarity. Soluble polymers show a 10–25% increase in PCE in inverted device configurations, while the device performance is independent of device polarity for less soluble DPP derivatives. The difference seems related to the polymer to fullerene weight ratio at the ZnO interface in inverted devices, which is higher for more soluble DPP polymers. Optimization of the nature of the cosolvent to narrow the fibril width of polymers in the blends toward the exciton diffusion length enhances charge generation. Additionally, the use of a retroreflective foil increases absorption of light. Combined, the effects afford a PCE of 9.6%, among the highest for DPP‐based polymer solar cells.     

Polymer waveguide sensor for early diagnostic and wellness monitoring

This paper unveils a platform to develop a compact, simple, reusable and disposable, and cost effective hand-held urinalysis device for home-health-care and doctor's office uses. A polymeric optical waveguide and colorimetric absorption were used as an optical sensor and sensing mode, respectively. The results of the tests show that the device was able to deliver quantitative results with the detection limits better than 0.1g/L, 0.2g/L, 0.025 g/L, and 0.1g/L for glucose, creatinine, albumin and total protein, respectively. There are some superiorities of this device as compared to the dip-stick counterpart, that are, better sensitivity, ability to deliver quantitative results and reusability. The device is being further miniaturized to use a LED and photodiode as a light source and detector, respectively. It is believed the device has potential for early diagnostic and wellness monitoring tool.     

The possible use of PKZh-type devices (liquid purity control devices) in the analysis of cell suspensions

PKZh means "device for liquid purity control". A possibility is considered to use the native PKZh type device for carrying out quantitative analyses of cellular suspension components, for routine bacterial suspension, agglutinated bacterial suspension and erythrocyte suspension. The flowing photometric principle of particle recording, used in the device, allows to analyse biological suspensions with small amounts of components. The device provides a differential count of some cells and their conglomerates in six dimensional ranges, within the frames of 1-25 micron or higher. The time consumption for one sample analysis is 10-15 seconds.     

A pedal corer for the quantitative sampling of sediments and benthic organisms in submerged areas accessible on foot

This paper presents a new device to collect quantitative samples of sediment and benthic organisms. The device is specially designed for sampling with the advantages of box-corer or Eckman dredges in submerged areas that are accessible on foot. The pedal corer is a simple, lightweight, user-friendly device that does not disturb the sediment structure and provides easy access to the sample contained inside the core. With this device, sampling in shallow water zones that are constantly submerged is made easy and sampling time is extended in intertidal zones. Handling editor: J. Saros     

Reduction of knee range of motion during continuous passive motion due to misaligned hip joint centre

When using continuous passive motion (CPM) devices, appropriate setting of the device and positioning of the patient are necessary to obtain maximum range of motion (ROM). In this study, the ROMs in both the knee joint and CPM device during CPM treatment were measured using a motion analysis system for three different CPM devices. Additionally, the trajectories of the angles at the knee for hip joint misalignments were evaluated using kinematic models of the three CPM devices. The results showed that discrepancies in ROM between the knee joints and the CPM device settings during CPM treatment were revealed regardless of the CPM device and that the effect of misalignment is dependent on the design of the CPM device. The present technology could be applied for the development of a better design configuration for the CPM device to reduce the discrepancy in ROM at the knee joint.     

Reduction of knee range of motion during continuous passive motion due to misaligned hip joint centre

When using continuous passive motion (CPM) devices, appropriate setting of the device and positioning of the patient are necessary to obtain maximum range of motion (ROM). In this study, the ROMs in both the knee joint and CPM device during CPM treatment were measured using a motion analysis system for three different CPM devices. Additionally, the trajectories of the angles at the knee for hip joint misalignments were evaluated using kinematic models of the three CPM devices. The results showed that discrepancies in ROM between the knee joints and the CPM device settings during CPM treatment were revealed regardless of the CPM device and that the effect of misalignment is dependent on the design of the CPM device. The present technology could be applied for the development of a better design configuration for the CPM device to reduce the discrepancy in ROM at the knee joint.     

Non-chemical biofouling control in heat exchangers and seawater piping systems using acoustic pulses generated by an electrical discharge

Acoustic pulses generated by an electrical discharge (pulsed acoustics) were investigated as a means for biofouling control in two test formats, viz. a 5/8" outside diameter titanium tube and a mockup heat exchanger. The pulsed acoustic device, when operated at 17 kV, demonstrated 95% inhibition of microfouling over a 20 ft length of titanium tube over a 4-week period, comparable to chlorination in combination with a high-velocity flush. The pulsed acoustic device inhibited microfouling over a downstream distance of 15 ft, therefore, a single pulsed acoustic device is theoretically capable of protecting at least 30 ft of tube from microfouling (15 ft on either side of the device). A correlation between acoustic intensity in the frequency range 0.01-1 MHz and the level of biofouling inhibition was observed. The threshold acoustic intensity for microfouling inhibition was determined for this frequency range. It was also observed that the orientation of the device is critical to obtaining microfouling inhibition.     

Semimicrotitration device for cholinesterase assay

A semimicrotitration device for reaction volumes of 0.5 to 2 ml and effective stirring of reaction solution or suspension is described. The principal part of the device is a combined glass electrode functioning as a reaction vessel (combined "cup"-glass electrode). Characteristics of the device are small volumes and great reliability. Nonspecific cholinesterase activities measured in rat plasma and liver tissue homogenates and compared with the activities of the same tissue and plasma samples measured radiometrically and spectrophotometrically illustrate the applicability of the device. The method is best suited for kinetic studies with multiple substrates of esterases, either in the soluble form or in tissue homogenates.     

An optimized device for staining electron microscopy grids

Proper staining of grids is critical for transmission electron microscopy (TEM). Staining must be done as quickly as possible using minimal reagents and with consideration for the environment. We developed a new device for efficient staining of multiple TEM grids. We studied reagent evaporation, rinsing volume, flow rate and re-use of uranyl acetate, and provide here a procedure for efficient staining using the new device. Our device permits TEM grids to be stained with less reagent than alternative staining apparatuses; staining requires a total volume of 260 μl for five grids. Reagent evaporation is less than 6% even if used at 37° C. Moreover, our staining apparatus reduces chemical waste and shortens experiment time by staining several grids simultaneously. Our staining device is a compromise between time-consuming single grid processing and expensive commercial devices that consume large amounts of reagents.     

A new guide and 2 new cruciate ligament anchors for securing prosthetic cruciate ligaments to the femur

A new drilling device for the correct localization of drilling holes has been developed for the fixation of cruciate ligament prostheses. We describe how the device is employed under surgical operating conditions. Its accuracy in application is demonstrated in a cadaver knee. The device has also been used clinically with success. Two new anchors for the fixation of the ligaments are proposed.