Origami-inspired paper sensor could test for malaria and HIV for less than 10 cents, report chemists

 Inspired by the paper-folding art of origami, chemists at The University of Texas at Austin have developed a 3-D paper sensor that may be able to test for diseases such as malaria and HIV for less than 10 cents a pop. The sensors can be printed out on an office printer, and take less than a minute to assemble.

Such low-cost, "point-of-care" sensors could be incredibly useful in the developing world, where the resources often don't exist to pay for lab-based tests, and where, even if the money is available, the infrastructure often doesn't exist to transport biological samples to the lab.

"This is about medicine for everybody," says Richard Crooks, the Robert A. Welch Professor of Chemistry.

One-dimensional paper sensors, such as those used in pregnancy tests, are already common but have limitations. The folded, 3-D sensors, developed by Crooks and doctoral student Hong Liu, can test for more substances in a smaller surface area and provide results for more complex tests.

"Anybody can fold them up," says Crooks. "You don't need a specialist, so you could easily imagine an NGO with some volunteers folding these things up and passing them out. They're easy to produce as well, so the production could be shifted to the clientele as well. They don't need to be made in the developed world."

The results of the team's experiments with the origami Paper Analytical Device, or oPAD, were published in October in the Journal of the American Chemical Society and this week in Analytical Chemistry.

The inspiration for the sensor came when Liu read a pioneering paper by Harvard University chemist George Whitesides.

Whitesides was the first to build a three-dimensional "microfluidic" paper sensor that could test for biological targets. His sensor, however, was expensive and time-consuming to make, and was constructed in a way that limited its uses.

"They had to pattern several pieces of paper using photolithography, cut them with lasers, and then tape them together with two-sided tape," says Liu, a member of Crooks' lab. "When I read the paper, I remembered when I was a child growing up in China, and our teacher taught us origami. I realized it didn't have to be so difficult. It can be very easy. Just fold the paper, and then apply pressure."

Within a few weeks of experiments, Liu had fabricated the sensor on one simple sheet using photolithography or simply an office printer they have in the lab. Folding it over into multiple layers takes less than a minute and requires no tools or special alignment techniques. Just fingers.

Crooks says that the principles underlying the sensor, which they've successfully tested on glucose and a common protein, are related to the home pregnancy test. A hydrophobic material, such as wax or photoresist, is laid down into tiny canyons on chromatography paper. It channels the sample that's being tested -- urine, blood, or saliva, for instance -- to spots on the paper where test reagents have been embedded.

If the sample has whatever targets the sensor is designed to detect, it'll react in an easily detectable manner. It might turn a specific color, for instance, or fluoresce under a UV light. Then it can be read by eye.

"Biomarkers for all kinds of diseases already exist," says Crooks. "Basically you spot-test reagents for these markers on these paper fluidics. They're entrapped there. Then you introduce your sample. At the end you unfold this piece of paper, and if it's one color, you've got a problem, and if not, then you're probably OK."

Crooks and Liu have also engineered a way to add a simple battery to their sensor so that it can run tests that require power. Their prototype uses aluminum foil and looks for glucose in urine. Crooks estimates that including such a battery would add only a few cents to the cost of producing the sensor.

"You just pee on it and it lights up," says Crooks. "The urine has enough salt that it activates the battery. It acts as the electrolyte for the battery."

Story Source:

The above story is reprinted from materials provided by University of Texas at Austin.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Hong Liu, Richard M. Crooks. Paper-Based Electrochemical Sensing Platform with Integral Battery and Electrochromic Read-Out. Analytical Chemistry, 2012; 84 (5): 2528 DOI: 10.1021/ac203457h

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

Hydrogen peroxide goes green in undergrad's published paper on renewable energy

A chemistry major, MacKenzie applies hydrogen peroxide to algae, sawdust and grass clippings so that they can be more easily converted to biofuels like natural gas. She’s the lead author of an academic journal article on the topic.

What’s more, the hydrogen peroxide changes to water in the process.

“That’s one of the advantages to using this kind of pretreatment,” she said. “A lot of other treatments leave some toxic waste.”

The research could be applied in any setting with a stream of incoming organic waste. At landfills, for example, yard waste could be separated and fed into a machine designed to digest the material and convert it to methane gas. Such equipment is already being developed and used by MacKenzie’s mentor, Professor Jaron Hansen, at dairy farms in Utah and China.

With graduation coming in April, MacKenzie is polishing an Honors thesis that will demonstrate the optimal concentrations of hydrogen peroxide and UV light when processing sawdust and grass clippings.

“The thing that gets me most excited is the fact that this is a renewable energy source,” MacKenzie said. “I feel like I have a responsibility to figure out how to live more sustainably and be cleaner with the energy we use.”

Provided by Brigham Young University (news : web)

It's elemental: Paper celebrates discovery of iodine

George Luther, Maxwell P. and Mildred H. Harrington Professor at UD, is one of 11 internationally recognized co-authors on a paper commemorating 200 years of iodine research. The paper appeared on Friday, Dec. 2, in Angewandte Chemie, one of the prime chemistry journals in the world.

Most of us think of iodine as a liquid that comes in a little brown bottle to help heal cuts or as something that gets mixed in with table salt to prevent goiter. But the element that appears as number 53 in the periodic table was actually discovered during the Napoleonic Wars when French chemist Bernard Courtois was searching for an alternative to wood ashes as a feedstock for the production of saltpeter. Today, iodine has applications ranging from pharmaceuticals to semiconductors.

The element plays a role in a broad range of fields, including materials, medicine and physiology, atmospheric chemistry, geochemistry and marine chemistry. The latter is where Luther's expertise was called upon for the article. His section provides an overview of iodine and its major chemical forms in the marine environment.

"Iodine is incorporated into diatoms and other algae in the surface ocean," Luther says. "Upon death, some plankton sink to the sediments, and iodine is enriched in the sediments and their porewaters. There is also some release of gaseous iodine to the atmosphere from algal and plant sources. Weathering of the continents adds some iodine to the ocean via rivers to maintain the balance of about 0.45 micromolar total iodine that is in the ocean."

Apparently, Luther doesn't have to worry about running out of research opportunities any time soon. The authors conclude that in the ocean, the iodide–iodate transformation still offers challenges to biological and chemical oceanographers. At the same time, the biogenic, evolutionary origin of the high iodine levels encountered in marine sediments requires more research efforts.

However, the man who discovered iodine two centuries ago did not fare so well. Despite the scientific significance of his discovery and the growing commercial interest in iodine, Courtois did not capitalize on his discovery. He died in poverty on Sept. 27, 1838, at the age of 62. Iodine production from seaweed quickly became a major economic activity in the coastal regions of Europe, and others went on to benefit from his finding.

More information: Commemorating Two Centuries of Iodine Research: An Interdisciplinary Overview of Current Research” appeared on Friday, Dec. 2, in Angewandte Chemie., Frithjof C. Küpper, et al.

Provided by University of Delaware (news : web)

Recycling thermal cash register receipts contaminates paper products with BPA

Kurunthachalam Kannan and Chunyang Liao explain that manufacturers produce more than 8 billion pounds of BPA worldwide every year. Research links BPA with a variety of harmful health effects. BPA has been used in plastic water bottles, the lining of food cans and a variety of other products. But how much do non-food sources contribute to humans' daily BPA exposure? BPA coats the surfaces of thermal receipts, where it acts as a developer for the printing dye. To see whether this source of BPA was a concern, the researchers analyzed hundreds of samples of thermal cash register receipts and 14 other types of paper products from the U.S., Japan, Korea and Vietnam.

They found BPA on 94 percent of the receipts. The only receipts with that were BPA-free were those from Japan, which phased out this use of BPA in 2001. BPA was in most of the other types of paper products, with tickets, newspapers and flyers having the highest concentrations. But these levels still paled in comparison to BPA on receipts, which the study said are responsible for more than 98 percent of consumer exposure to BPA from paper. The researchers estimate that receipts contribute about 33.5 tons of BPA to the environment every year in the U.S. and Canada. They note that handling of paper products can contribute up to 2 percent of the total daily BPA exposures in the general population, and that fraction can be much higher in occupationally exposed individuals.

More information: Widespread Occurrence of Bisphenol A in Paper and Paper Products: Implications for Human Exposure, Environ. Sci. Technol., Article ASAP. DOI: 10.1021/es202507f

Abstract
Bisphenol A (BPA) is used in a variety of consumer products, including some paper products, particularly thermal receipt papers, for which it is used as a color developer. Nevertheless, little is known about the magnitude of BPA contamination or human exposure to BPA as a result of contact with paper and paper products. In this study, concentrations of BPA were determined in 15 types of paper products (n = 202), including thermal receipts, flyers, magazines, tickets, mailing envelopes, newspapers, food contact papers, food cartons, airplane boarding passes, luggage tags, printing papers, business cards, napkins, paper towels, and toilet paper, collected from several cities in the USA. Thermal receipt papers also were collected from Japan, Korea, and Vietnam. BPA was found in 94% of thermal receipt papers (n = 103) at concentrations ranging from below the limit of quantitation (LOQ, 1 ng/g) to 13.9 mg/g (geometric mean: 0.211 mg/g). The majority (81%) of other paper products (n = 99) contained BPA at concentrations ranging from below the LOQ to 14.4 µg/g (geometric mean: 0.016 µg/g). Whereas thermal receipt papers contained the highest concentrations of BPA (milligram-per-gram), some paper products, including napkins and toilet paper, made from recycled papers contained microgram-per-gram concentrations of BPA. Contamination during the paper recycling process is a source of BPA in paper products. Daily intake (DI) of BPA through dermal absorption was estimated based on the measured BPA concentrations and handling frequency of paper products. The daily intake of BPA (calculated from median concentrations) through dermal absorption from handling of papers was 17.5 and 1300 ng/day for the general population and occupationally exposed individuals, respectively; these values are minor compared with exposure through diet. Among paper products, thermal receipt papers contributed to the majority (>98%) of the exposures.

Provided by American Chemical Society (news : web)

Research paper on cancer drug accorded 'VIP' status

The drug, originally known as STX64 and now as Irosustat, was designed and chemically synthesised in the Medicinal Chemistry Group of the University’s Department of Pharmacy & Pharmacology.

STX64 and its associated intellectual property formed part of the assets of the Bath-Imperial College spin-out company Sterix Ltd that was co-founded by Professor Barry Potter and was acquired by the pharmaceutical company Ipsen in 2004.

The drug has been developed by Ipsen in recent years, with human clinical trials carried out in hormone-dependent breast cancer, endometrial cancer and in male prostate cancer.

The drug can be given orally and is termed a ‘first-in-class’ irreversible steroid sulfatase inhibitor. It works by blocking an enzyme pathway that gives rise to precursors of the steroid hormones oestrogen and an androgen that can trigger the growth of hormone-dependent tumours.

The new paper, entitled ’Structure-activity relationship of the clinical steroid sulfatase inhibitor Irosustat (STX64, BN83495),’ has appeared in the November issue of the journal and describes how the research team has modified the chemical structure of the drug to explore the effects on biological activity.

Referee reports on the paper were so strong that the journal ChemMedChem accorded it coveted ‘VIP’ status and also invited the authors to design a cover feature for the publication.

Professor Potter, with colleagues Dr Lawrence Woo and Dr Mark Thomas of the Department of Pharmacy & Pharmacology, designed an imaginative cover feature illustrating the drug molecule flanked by renderings of the target enzyme, all superimposed upon a false colour staining of the target protein in malignant breast cancer cells.

The publisher Wiley has also issued a feature on this paper in its own Chem Views online news magazine entitled ’Best in Class’.

Professor Potter said: “It is highly rewarding for the whole team to see the progression of this drug from the bench in a University of Bath synthetic laboratory all the way into diverse major clinical trials in cancer patients and also to see such continuing academic peer-recognition.

“This work emphasises the strength of medicinal chemistry at the University of Bath and demonstrates that academic scientists can play a key role in the drug discovery and development processes, traditionally a preserve of the pharmaceutical industry.”

More information: The full paper can be accessed through the ChemMedChem website.

Provided by University of Bath (news : web)

New paper examines future of seawater desalinization

A paper co-authored by William Phillip of the University of Notre Dame's Department of Chemical and Biomolecular Engineering and Menachem Elimelech, Robert Goizueta Professor of Environmental and Chemical Engineering at Yale University, appearing in this week's edition of the journal Science offers a critical review of the state of seawater desalination technology.

Elimelech and Phillip and examine how seawater desalination technology has advanced over the past 30 years, in what ways the state-of-the-art technology can be improved, and if seawater desalination is a sustainable technological solution to global water shortages.

"At present, one-third of the world's population lives in water stressed countries, Phillip said. "Increasing population, contamination of fresh water sources and climate change will cause this percentage to increase over the coming decade. Additionally, the social and ecological benefits of adequate fresh water resources are well-documented. Therefore, it is important to find a way to alleviate this stress with a sustainable solution."

The authors point out that in recent years, large-scale seawater desalination plants have been built in water-stressed countries to augment available water resources and construction of new desalination plants is expected to increase in the near future. Despite major advancements in desalination technologies, seawater desalination is still more energy intensive compared to conventional technologies for the treatment of fresh water. There are also concerns about the potential environmental impacts of large-scale seawater desalination plants.

In their Science paper, Elimelech and Phillip review the possible reductions in energy demand by state-of-the-art desalination technologies, the potential role of advanced materials and innovative technologies in improving the performance, and the sustainability of desalination as a technological solution to global water shortages.

The authors believe that there are important policy implications in their Science paper.

"Seawater desalination is an energy-intensive process; desalinating seawater consumes significantly more energy than treating traditional fresh water sources," Phillip said. "However, these traditional sources aren't going to be able to meet the growing demand for water worldwide. Several options already exist to augment fresh water sources -- including the treatment of low-quality local water sources, water recycling and reuse and water conservation, -- understanding where seawater desalination fits into this portfolio of water supply options is critical. Hopefully, our paper helps provide some of the information needed to inform the decisions of policy makers, water resource planers, scientists, and engineers on the suitability of desalination as a means to meet the increasing demands for water."

Phillip, who joined the Notre Dame faculty this year, is interested in examining how membrane structure and chemistry affect the transport of chemicals across a variety of membranes. Understanding the connection between functionality and property enables the design and fabrication of next generation membranes that provide more precise control over the transport of chemical species. These material advantages can be leveraged to design more effective and energy-efficient systems. Chemical separations at the water- energy nexus (e.g. desalination) is one area where this knowledge can be applied.

Story Source:

The above story is reprinted (with editorial adaptations ) from materials provided by University of Notre Dame, via EurekAlert!, a service of AAAS.

Journal Reference:

Menachem Elimelech, William A. Phillip. The Future of Seawater Desalination: Energy, Technology, and the Environment. Science, 5 August 2011: Vol. 333 no. 6043 pp. 712-717 DOI: 10.1126/science.1200488

Student turns paper mill waste into ‘green’ material for industrial applications

A method to use paper mill waste to produce ecologically friendly, industrial foams from renewable resources has been developed by a graduate student in agriculture at the Hebrew University of Jerusalem.

Foams are used for numerous day-to-day uses, including in the manufacture of furniture and car interiors. In many composite material applications, they are used as core material in "sandwich" panels to achieve high strength, weight reduction, energy dissipation and insulation. Conventional foams are produced from polymers such as polyurethane, polystyrene, polyvinyl chloride (PVC) and polyethylene terephthalate (PET). Since all of these current foams rely on fossil oil, they present a clear environmental disadvantage.

Shaul Lapidot, a Ph.D. student of Prof. Oded Shoseyov, along with his laboratory colleagues at the Robert H. Smith Faculty of Agriculture, Food and Environment of the Hebrew University in Rehovot, has formulated a procedure for production of nano-crystalline cellulose (NCC) from paper mill waste. NCC is further processed into composite foams for applications in the composite materials industry as bio-based replacement for synthetic foams.

The process of paper production involves loss of all fibers with dimensions lower than the forming fabric mesh. Consequently around 50% of the total fibers initially produced are washed away as sludge. In Europe alone, 11 million tons of waste are produced annually by this industry, creating an incentive for finding alternative uses and different applications for the wastes.

Lapidot has found that fibers from paper mill sludge are a perfect source for NCC production due to their small dimensions which require relatively low energy and chemical input in order to process them into NCC. He also developed the application of NCC into nano-structured foams. This is further processed into composite foams for applications in the composite materials industry to be used as bio-based replacement for synthetic foams.

NCC foams that Lapidot and his colleagues have recently developed are highly porous and lightweight. Additional strengthening of the foams was enabled by infiltration of furan resin, a hemicellulose-based resin produced from raw crop waste, such as that remaining from sugar cane processing, as well as oat hulls, corn cobs and rice hulls.

The new NCC reinforced foams display technical performance which matches current high-end synthetic foams. The technology was recently licensed from Yissum, the technology transfer company of the Hebrew University, by Melodea Ltd., an Israeli-Swedish start-up company which aims to develop it for industrial scale production.

Lapidot's development has led to his being awarded one of the Barenholz Prizes that were presented on June 21 at the Hebrew University Board of Governors meeting. The award is named for its donor, Prof. Yehezkel Barenholz of the Hebrew University-Hadassah Medical School.

Story Source:

The above story is reprinted (with editorial adaptations) from materials provided by Hebrew University of Jerusalem, via AlphaGalileo.