Low Cost and Lithography-free Stamp fabrication for Microcontact Printing

Microcontact printing (µCP) is a commonly used technique for patterning proteins of interest on substrates. The cells take the shape of these printed patterns. This technique is used to explore the effect of cellular morphology on their various functions such as survival, differentiation, migration, etc. An essential step for µCP is to fabricate a stamp from a silicon mould, prepared using lithography. Lithography is cost intensive and needs a high level of expertise to handle the instrumentation. Also, one stamp can be used to print patterns of one size and shape. Here, to overcome these limitations, we devised a low-cost fabrication technique using readily available objects such as injection needles and polystyrene beads. We patterned the C2C12, myoblasts cells on the shapes printed using lithography-free fabricated stamps. We further exploited the surface curvature of the stamp to vary the size of the print either by changing the applied load and/or the substrate stiffness. We showed that the print dimension could be predicted well by using JKR theory of contact mechanics. Moreover, some innovative improvisations enabled us to print complex shapes, which would be otherwise difficult with conventional lithography technique. We envisage that this low cost and easy to fabricate method will allow many research laboratories with limited resources to perform exciting research which is at present out of their reach.

Multilevel fluidic flow control in a rotationally-driven polyester film microdevice created using laser print, cut and laminate

This paper presents a simple and cost-effective polyester toner microchip fabricated with laser print and cut lithography (PCL) to use with a battery-powered centrifugal platform for fluid handling. The combination of the PCL microfluidic disc and centrifugal platform: (1) allows parallel aliquoting of two different reagents of four different volumes ranging from nL to μL with an accuracy comparable to a piston-driven air pipette; (2) incorporates a reciprocating mixing unit driven by a surface-tension pump for further dilution of reagents, and (3) is amenable to larger scale integration of assay multiplexing (including all valves and mixers) without substantially increasing fabrication cost and time. For a proof of principle, a 10 min colorimetric assay for the quantitation of the protein level in the human blood plasma samples is demonstrated on chip with a limit of detection of ∼5 mg mL(-1) and coefficient of variance of ∼7%.

Phosphate Detection through a Cost-Effective Carbon Black Nanoparticle-Modified Screen-Printed Electrode Embedded in a Continuous Flow System

An automatable flow system for the continuous and long-term monitoring of the phosphate level has been developed using an amperometric detection method based on the use of a miniaturized sensor. This method is based on the monitoring of an electroactive complex obtained by the reaction between phosphate and molybdate that is consequently reduced at the electrode surface. The use of a screen-printed electrode modified with carbon black nanoparticles (CBNPs) leads to the quantification of the complex at low potential, because CBNPs are capable of electrocatalitically enhancing the phosphomolybdate complex reduction at +125 mV versus Ag/AgCl without fouling problems. The developed system also incorporates reagents and waste storage and is connected to a portable potentiostat for rapid detection and quantification of phosphate. Main analytical parameters, such as working potential, reagent concentration, type of cell, and flow rate, were evaluated and optimized. This system was characterized by a low detection limit (6 μM). Interference studies were carried out. Good recovery percentages comprised between 89 and 131.5% were achieved in different water sources, highlighting its suitability for field measurements.

A Low-Cost Inkjet-Printed Glucose Test Strip System for Resource-Poor Settings

BACKGROUND

The prevalence of diabetes is increasing in low-resource settings; however, accessing glucose monitoring is extremely difficult and expensive in these regions. Work is being done to address the multitude of issues surrounding diabetes care in low-resource settings, but an affordable glucose monitoring solution has yet to be presented. An inkjet-printed test strip solution is being proposed as a solution to this problem.

METHODS

The use of a standard inkjet printer is being proposed as a manufacturing method for low-cost glucose monitoring test strips. The printer cartridges are filled with enzyme and dye solutions that are printed onto filter paper. The result is a colorimetric strip that turns a blue/green color in the presence of blood glucose.

RESULTS

Using a light-based spectroscopic reading, the strips show a linear color change with an R(2) = .99 using glucose standards and an R(2) = .93 with bovine blood. Initial testing with bovine blood indicates that the strip accuracy is comparable to the International Organization for Standardization (ISO) standard 15197 for glucose testing in the 0-350 mg/dL range. However, further testing with human blood will be required to confirm this. A visible color gradient was observed with both the glucose standard and bovine blood experiment, which could be used as a visual indicator in cases where an electronic glucose meter was unavailable.

CONCLUSIONS

These results indicate that an inkjet-printed filter paper test strip is a feasible method for monitoring blood glucose levels. The use of inkjet printers would allow for local manufacturing to increase supply in remote regions. This system has the potential to address the dire need for glucose monitoring in low-resource settings.

Low-cost, high-throughput fabrication of cloth-based microfluidic devices using a photolithographical patterning technique

In this work, we first report a facile, low-cost and high-throughput method for photolithographical fabrication of microfluidic cloth-based analytical devices (μCADs) by simply using a cotton cloth as a substrate material and employing an inexpensive hydrophobic photoresist laboratory-formulated from commercially available reagents, which allows patterning of reproducible hydrophilic-hydrophobic features in the cloth with well-defined and uniform boundaries. Firstly, we evaluated the wicking properties of cotton cloths by testing the wicking rate in the cloth channel, in combination with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses. It is demonstrated that the wicking properties of the cloth microfluidic channel can be improved by soaking the cloth substrate in 20 wt% NaOH solution and by washing the cloth-based microfluidic patterns with 3 wt% SDS solution. Next, we studied the minimum dimensions achievable for the width of the hydrophobic barriers and hydrophilic channels. The results indicate that the smallest width for a desired hydrophobic barrier is designed to be 100 μm and that for a desired hydrophilic channel is designed to be 500 μm. Finally, the high-throughput μCADs prepared using the developed fabrication technique were demonstrated for colorimetric assays of glucose and protein in artificial urine samples. It has been shown that the photolithographically patterned μCADs have potential for a simple, quantitative colorimetric urine test. The combination of cheap cloth and inexpensive high-throughput photolithography enables the development of new types of low-cost cloth-based microfluidic devices, such as "microzone plates" and "gate arrays", which provide new methods to perform biochemical assays or control fluid flow.

Low-cost fabrication of centimetre-scale periodic arrays of single plasmid DNA molecules

We report the development of a low-cost method to generate a centimetre-scale periodic array of single plasmid DNA molecules of 11 kilobase pairs. The arrayed DNA molecules are amenable to enzymatic and physical manipulations.

Open-source 3D-printable optics equipment

Just as the power of the open-source design paradigm has driven down the cost of software to the point that it is accessible to most people, the rise of open-source hardware is poised to drive down the cost of doing experimental science to expand access to everyone. To assist in this aim, this paper introduces a library of open-source 3-D-printable optics components. This library operates as a flexible, low-cost public-domain tool set for developing both research and teaching optics hardware. First, the use of parametric open-source designs using an open-source computer aided design package is described to customize the optics hardware for any application. Second, details are provided on the use of open-source 3-D printers (additive layer manufacturing) to fabricate the primary mechanical components, which are then combined to construct complex optics-related devices. Third, the use of the open-source electronics prototyping platform are illustrated as control for optical experimental apparatuses. This study demonstrates an open-source optical library, which significantly reduces the costs associated with much optical equipment, while also enabling relatively easily adapted customizable designs. The cost reductions in general are over 97%, with some components representing only 1% of the current commercial investment for optical products of similar function. The results of this study make its clear that this method of scientific hardware development enables a much broader audience to participate in optical experimentation both as research and teaching platforms than previous proprietary methods.

3D printing: making things at the library

3D printers are a new technology that creates physical objects from digital files. Uses for these printers include printing models, parts, and toys. 3D printers are also being developed for medical applications, including printed bone, skin, and even complete organs. Although medical printing lags behind other uses for 3D printing, it has the potential to radically change the practice of medicine over the next decade. Falling costs for hardware have made 3D printers an inexpensive technology that libraries can offer their patrons. Medical librarians will want to be familiar with this technology, as it is sure to have wide-reaching effects on the practice of medicine.

Printing of sub-100-nm metal nanodot arrays by carbon nanopost stamps

This work reports an efficient method to fabricate hexagonally patterned metal nanodot arrays at the sub-100-nm scale, which is based on contact printing via novel nanometer-scaled stamps. Vertically aligned carbon nanoposts, supported by hexagonally ordered nanochannels of anodic aluminum oxide templates, are employed as the stamping platform to directly transfer controlled metal nanodot arrays. Using the fabrication platform, a number of patterned metal nanodot arrays made of Au, Cu, Ni, Ag, Pt, Al, and Ti can be contact-printed over large substrate areas in ambient conditions. The size, density, and interdistance of the printed nanodots are controllable with a tight correspondence to the mother stamp geometries, which can be precisely tuned by modifying the pore dimensions of the alumina matrixes. An advanced example of contact printing of metal nanoparticles is successfully demonstrated by the controlled formation of nanodot arrays in a specific area.

Nanofabrication at high throughput and low cost

The task of nanofabrication can, in principle, be divided into two separate tracks: generation and replication of the patterned features. These two tracks are different in terms of characteristics, requirements, and aspects of emphasis. In general, generation of patterns is commonly achieved in a serial fashion using techniques that are typically slow, making this process only practical for making a small number of copies. Only when combined with a rapid duplication technique will fabrication at high-throughput and low-cost become feasible. Nanoskiving is unique in that it can be used for both generation and duplication of patterned nanostructures.

John Lawson's "A New Voyage to Carolina": notes on the publication history of the London (1709) edition

John Lawson's "A New Voyage to Carolina," an important source document for American colonial natural history, was first printed in 1709 in "A New Collection of Voyages and Travels," a two-volume set that also contained travel books translated by John Stevens. Lawson's publishers were leaders in the book trade of early eighteenth century London, and the "New Voyage" is typical of the resurgent popular interest in foreign travel narratives and exotic flora and fauna that began in the late 1600s. The "New Collection" was among the earliest examples of books published in serial instalments or fascicles, a marketing strategy adopted by London booksellers to broaden the audience and increase sales. Analysis of London issues of the "New Voyage" indicates that the 1709, 1711, 1714, and 1718 versions are simply bindings of the original, unsold sheets from the 1709 "New Collection" edition, differing only by new title-pages, front matter, and random stop-press corrections of type-set errors. Lawson's "New Voyage" illustrates important aspects of the British book trade during the hand press period of the early eighteenth century.

Low-cost printing of computerised tomography (CT) images where there is no dedicated CT camera

Many developing countries still rely on conventional hard copy images to transfer information among physicians. We have developed a low-cost alternative method of printing computerised tomography (CT) scan images where there is no dedicated camera. A digital camera is used to photograph images from the CT scan screen monitor. The images are then transferred to a PC via a USB port, before being printed on glossy paper using an inkjet printer. The method can be applied to other imaging modalities like ultrasound and MRI and appears worthy of emulation elsewhere in the developing world where resources and technical expertise are scarce.

Patterns and costs of printed and online journal usage

This study in an academic medical sciences library setting examines the correlation of usage of a matched set of print and online titles, the validity of e-journals usage statistics and the impact of online journals on print journal usage. The print and online usage was determined for 270 journals, both versions of which were available. Print usage was determined annually since 1997 using the reshelving and the error-copies method. Online usage statistics were delivered by five publishers and corrected for redundant multiple accesses. Print journal usage decreased by 22.3 and 30.2% respectively over each of 2 years after the introduction of online journals. Journals published both in print and online lost 30.4% of their print usage within 2 years. The total loss of usage of print-only titles in the same period was somewhat higher, at 45.8%. The average correlation between online and print usage is 0.60 and 0.67 respectively. For the examined titles, users accessed the online versions ten times as often as the print version. Two clearly distinguishable groupings emerged: while with Academic Press and Elsevier, e-journal usage exceeded print usage by a factor of 3 or 4, the e-journals of Blackwell, HighWire and Springer were used on average 14.6 times as frequently as the corresponding print journals. Each usage of a print article cost 2.79-50.82 Euro, each usage of an online article 0.31-15.10 Euro, depending on the publisher. On average, the usage of an online article was 5.4 times cheaper. Within 2-3 years the usage of online journals has outstripped that of print titles by a factor of ten, but the specific spectrum of usage remains much the same as when only print journals alone existed. Print titles not available online suffer a greater decline in usage compared with print/online journals. This confirms that what is read or purchased is determined primarily by ease of access and that there is a steady tendency to reduce the multiplicity of access modes to a manageable few. The availability of journals online seems to have created a new clientele, at least in the case of the German-language Springer journals. The connection between supplier and supply is much less clear with e-journals than it is with print titles. Therefore it is very important to stress and encourage the role of the library as the supplier of this sort of information in the university environment. Collection building issues are discussed in the light of the results.

Operating the production calculus: ordering a production system in the print industry

The topic of shop-floor work has been extensively examined within sociology. However, the organizational structures within which this work takes place have, in the most part, been taken as unexamined givens. Yet, their operation is also the shop-floor work of some people. This paper examines the way in which the stable organizational structures within which shop-floor work takes place are achieved. It is based upon a fieldwork investigation of a large commercial printer and focuses upon the collaborative work of those who are involved in scheduling the production of a job and their use of 'the production calculus' in planning the work of the site. The print industry is undergoing considerable technological change and scheduling technologies have been developed to automate this work. However, there has been little take up of these technologies and the paper also considers how the characteristics of operating the production calculus in practice may account for this.

Non-indexed medical journals in the Web: new perspectives in the medical literature

Many medical journals, publishing in national languages, meet serious financial problems and difficulties when they attempt to become indexed in the international indices. Obviously, this not only affects the scientific quality of non-indexed medical journals (NIMJs) but also affects the awareness of the scientific community of topics with apparently local but potentially broader scientific significance. This is a reality for over 100 Greek medical journals, none of which has a life longer than 30 years or more than 2000 subscribers. Among them, the 'Archives of Hellenic Medicine' (AHM) is published and sponsored by the Athens Medical Society (the oldest medical society in Greece founded in 1835). This peer-reviewed Journal is being published for 13 years, bimonthly, in Greek. Attempting to overcome the above mentioned problems and to be involved in the process of discovering the most effective way of scientific 'skywriting', 2 years ago, the AHM entered full-text in the Web and it was decided that up to 500% of its volume should be covered by English-language papers. As a result, the AHM are now included in the main Web lists of medical journals and their home page is linked in many academic pages having approximately 500 hits/month. Furthermore, 45 retrievals of AHM's English-language papers or English abstracts of Greek-language articles were reported by e-mail response from abroad. Considered apart from the paper-publishing, the expenses of the digital publishing of the AHM are about half of those of paper-publishing, as they were before the appearance of the Journal in the Web. Up to now, about 40% of the Journal's digital publishing cost is covered by advertisements included in its pages and by a modification of its paper-publishing policy. It is concluded that the international scientific community is not indifferent for information published in NIMJs. Medical national minorities working abroad express special interest for this type of information. The Web makes the NIMJs accessible to these potential readers, who would never have the chance to acquire them in their printed form.

Hardcopy recording technologies for digitally formatted image data

The hardcopy recording technologies of video cameras, slow-scan (digital spot) recorders, and laser film printers are presented and compared. Slow-scan (digital spot) recorders offer a few advantages when compared with multiformat video cameras. But only laser film printers provide the high-quality hardcopy recordings and speed required by newer digital imaging modalities.

Videophotolaryngography using a new low cost video printer. Instant electronic filmless photography

We introduce a new concept of electronic videophotography of the larynx on the television screen using a new Mitsubishi video printer. With this method no standard film or chemical processing are used. Black and white prints of the television image can be electronically reproduced in less than 15 seconds by pressing a button on the video printer. This method is of great value for documentation of the progression of disease and comparison of the preoperative and postoperative appearances of the larynx. The printout of the black and white television image of the larynx can be attached to the patient's chart as a permanent pictorial record. Such prints can also be given to the patient or can be sent to the referring physician, the radiotherapist, and others involved in management of the patient. This method is also useful for demonstration of a pathological condition and for teaching at head and neck tumor conferences.