Microencapsulation Report

NASA has released a report on their investigations into microencapsulation of targeted cancer drugs. This research was conducted in space, on the International Space Station. Here’s a link (pdf) to the full NASA ISS research report. And here’s a blub from the press release:

“Another experiment produced a potential medical advance, demonstrating a new and powerful method for delivering drugs to targets in the human body. Microgravity research on the station was vital to development of miniature, liquid-filled balloons the size of blood cells that can deliver medicine directly to cancer cells. The research was conducted for the Microencapsulation Electrostatic Processing System experiment.”

Abstract: Nearly monodisperse microcapsules with controllable porous surface morphologies were prepared by the in situ polymerization of melamine and formaldehyde with a template of nonionic surfactant micelles above the cloud point, inside which normal alkanes can be either encapsulated as phase change material or removed to obtain porous hollow spheres. The experimental results indicate that both the size and density of the pores on the microcapsule surface are tunable by changing the amount of core material (normal alkane) or the ratio of the polymer shell material to core material. The formation mechanism of the surface porosity was investigated by considering the polymerization temperature and the concentration of nonionic surfactants, which were used as the emulsifiers of core material droplets. The thermal gravimetry analysis proved that the microcapsules are thermally stable, and the heat treatment provided a new approach to preparing porous hollow microspheres.

Guoming Liu, Baoquan Xie, Dongsheng Fu, Yang Wang, Qiang Fu and Dujin Wang
J. Mater. Chem., 2009, 19, 6605 – 6609, DOI: 10.1039/b901102a

Researchers at UIUC have developed microcapsules of carbon nanotubes that are resistive in electric circuits when undisturbed, but become conductive when ruptured. This technology has the potential to make more failsafe circuits and more reliable batteries. From the RSC article:

Jeffrey Moore, at the University of Illinois at Urbana-Champaign, and colleagues made microcapsules with robust walls and filled them with carbon nanotubes (CNTs). They then ruptured the microcapsules using vigorous stirring and measured the contents’ ability to conduct electricity between two electric probes separated by around 100 micrometres. As the team swept the applied voltage from minus to plus 50 volts, the CNTs migrated towards the probe tips. They aligned with the electric field and completed the circuit, enabling the current to flow.

They found the best capsules were between 280 and 350 micrometres – smaller ones were too difficult to break and larger ones broke too easily.

‘Battery safety and lifetime are two problems that may benefit from this approach,’ says Moore. ‘You may want to restore electrical conductivity of damaged battery electrodes. On the other hand, if battery electrodes short circuit, the battery becomes dangerous and has the potential to explode. One may thus want to coat the electrodes with a resistive material to shut down a run-away battery. Exploring these ideas are some of our future plans.’

‘I think it is a neat approach that can become very useful if taken further,’ comments Vsevolod Rostovtsev, a nanotube expert at DuPont, Wilmington, US. ‘The capsules need to become smarter so that their precise and accurate placement could be effected. The broken microcapsule shell needs to be removed from the electronic device to reduce contamination.’

A Cambridge based company called BioBullets has developed an encapsulated poison of the same name intended to control the zebra mussel, and invasive bivalve that is clogging waterways worldwide. From a Business Weekly article:

Dr David Aldridge of the University of Cambridge’s Zoology department says that his company, BioBullets received approval to use its potassium chloride-loaded pellets in UK waterways from the Drinking Water Inspectorate (DWI) in December 2008, which was closely followed by a £500k grant from the Technology Strategy Board (TSB).

This TSB award is being match-funded by Anglian and Thames Water together with BioBullet’s industrial partner Tastetech, a specialist in microencapsulation technology for food ingredients and natural flavourings based in Bristol, which is expected to host the new manufacturing site.

BioBullets’ initial work has focused on the problem of the small but prevalent zebra mussel, quickly becoming one of the world’s biggest environmental and ecological pests, clogging the water systems of power plants, water treatment facilities, irrigation systems and industrial water intake structures.

BioBullets says that since arriving in the North American Great Lakes in the 1980s, zebra mussels have become a major bio-fouler, blocking the raw water cooling systems of power stations and water treatment works and costing between $1-5 billion every year.

Current control methods use chlorine to rein in the pest, which not only provides its own environmental concerns, but is not entirely efficient as the mussels can sense it and other toxic substances, limiting their exposure to the chemicals by closing their valves for up to three weeks.

BioBullets overcome these problems by packing potassium chloride into micros-copic particles made of fats, a ‘Trojan horse’ technique gets the toxic compound past the mussels’ defences as they transfer the particles along their gills and into their mouths.

The particles rapidly dissolve in the animals’ stomachs releasing a lethal dose of potassium chloride.

Dr Aldridge says his group is also working on a number of other invasive species, which is bringing in international funding from three different continents.

The National Oceanic and Atmospheric Administration in the US has awarded BioBullets a $120k (£75k) grant to develop novel formulations for invasive sea squirts, immobile marine invertebrates which extract food from seawater pumped through a branchial sac in their body cavity.

Researchers at the University of Duisburg-Essen in Germany have developed a self-healing nanocapsule coating for metal that will prevent corrosion. This is the first such coating that can be electroplated onto a metal surface. From the Technology Review article:

The self-healing metal can be electroplated, which opens up applications in construction, car manufacturing, and other industries that use or manufacture steel machines. (Nuts, bolts, and screws made of steel, which is susceptible to corrosion, are already electroplated with rustproof metals such as zinc and chromium.)

The new coating is around 15 micrometers thick and contains polymer capsules a few hundred nanometers in diameter. When the plating is scratched, the capsules should burst and release their contents – which could be a polymer capable of sealing the crack, or corrosion-inhibiting liquids.

So far, the researchers have made nanocapsule-infused coatings from metals or alloys including copper, zinc, and nickel. In principle, it should be possible to make them from any metal that can be electroplated, says Harald Holeczek, a Fraunhofer researcher who was involved in the work.

Although Holeczek and his colleagues haven’t yet demonstrated the material’s self-healing property, being able to incorporate liquid-filled nanocapsules into electroplated layers is significant, says Michael Kessler, a materials science and engineering professor at Iowa State University. “This is the first self-healing coating that can be electroplated,” he says. “The advantage is that electroplating is a widely used industrial process.”

A press release from the American Institute for Plastic Surgery discusses their use of a microsphere-enhanced collagen dermal filler to reduce wrinkles:

Artefill is a simple, in-office procedure that takes approximately fifteen minutes to complete. A patient is injected with the product similar to other dermal fillers with the key difference being its lasting effect. The unique microspheres in Artefill are not absorbed by the body and therefore provide the support the skin needs for long lasting natural feeling results. This is different from temporary dermal fillers that are made of different kinds of natural or synthetic materials that are completely absorbed by the body over time and require repeat injections to maintain wrinkle correction. A skin test is required prior to treatment or approximately four (4) weeks ahead of time, to ensure a patient is not allergic to the collagen or anesthetic in Artefill.

From a DEK press release:

Extending its capabilities for placing solder spheres at high speed, DEK’s proven DirEKt Ball Placement(TM) process now enables accurate solder sphere deposition for spheres as small as 200µm in diameter with pitches as tight as 300µm. With the ability to achieve this accuracy and precision at a first pass yield of over 99.99%, DirEKt Ball Placement delivers the speeds necessary for modern package manufacture without sacrificing anything in the way of performance.

Unlike alternative methods that employ serial approaches for placement of solder balls, the parallel print process of DirEKt Ball Placement allows for unmatched, repeatable accuracy and exceptionally fast cycle times which are completely independent of I/O count. While these statistics are arguably impressive and consistent with requirements for next-generation wafer-level CSP devices, DEK is also upholding its pledge to continuously enhance DirEKt Ball Placement capability.

In an article on the research that takes place on the International Space Station, a NASA scientist discusses a patented drug microencapsulation system that was developed aboard the Space Station. Their targeted microcapsule research was conducted on prostate cancer in mice. From the article:

“One challenge we have is that it takes time for the results of our experiments to turn into benefits for everyone,” said Julie Robinson, program scientist-International Space Station, based at the Johnson Space Center in Houston. “People are familiar with the spinoffs of the Apollo mission, but don’t know what the Space Station is doing now. The clinical trial and research and development trial processes take a little while.”

For example, a microencapsulated system for medicine was recently patented and is entering the testing phase on Earth.

Astronauts aboard the ISS tested a way of encapsulating a drug in a microcapsule to target a specific area of the body when injected. Their research focused on prostate cancer in mice.

“After the Columbia accident happened, we couldn’t make anymore in space. Instead we sharpened our pencils, because we knew this was a desirable system to have, and developed a machine to make the microcapsules on Earth,” said Ms. Robinson.

Iranian chemists at Tehran University have been experimenting with drug release using various types of nanocapsules. Recently they have developed a polymer nanocapsule for administering Penicillin-G. From the article at Farsnews:

“Among the present nanoparticles, nanocapsules and micelle nanoparticles are more effective. Micelle nanoparticles release the drug in the body slowly, because of their interaction with central hydrophobe of nanoparticle, but nanocapsules, because of their thin layer, release the drug faster,” said Sepideh Khoee, an academic member of Tehran University and member of the research team.

“In this project, we succeeded in synthesizing a polymer nanocapsule for releasing Penicillin-G in body,” she continued.

The important point in this project is the dominant role of surfactants in making the preliminary and final emulsion.

Khoee explained that the size of nanoparticles will change by changing the amount and the kind of surfactants and in this project, 75 nanometer nanoparticles were produced by changing the kind and amount of two surfactants ‘Tween’ and ‘Span’.

The following Status Report was recently released by the Johnson Space Center of NASA regarding U.S. Patent #7,094,045, “Microencapsulation system and method”. NASA is granting an exclusive license for NuVue Therapeutic to practice the invention described in this patent.

[Federal Register: August 17, 2009 (Volume 74, Number 157)] [Notices] [Page 41455] From the Federal Register Online via GPO Access [wais.access.gpo.gov] [DOCID:fr17au09-107]

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

[Notice (09-072)]

Notice of Intent To Grant Partially Exclusive License

AGENCY: National Aeronautics and Space Administration.

ACTION: Notice of intent to grant partially exclusive license.

SUMMARY: This notice is issued in accordance with 35 U.S.C. 209(c)(1) and 37 CFR 404.7(a)(1)(i). NASA hereby gives notice of its intent to grant an exclusive license worldwide to practice the invention described and claimed in U.S. Patent No. 7,094,045, entitled“Microencapsulation System and Method”, U.S. Patent No. 7,295,309, entitled “Microparticle Analysis System and Method” to NuVue Therapeutics, Inc. (formerly known as Critical Care Innovations, Inc.), having its principal place of business in Fairfax, Virginia. The fields of use are for both clinical and veterinary applications in the production and applications of microcapsules and microencapsulation of all cyto-toxic anti-cancer drugs. Also included are externally- triggered microcapsules including the use of ultrasound and magnetic flux triggering technologies, in situ activation inside microcapsules, cell encapsulation, and urokinase and DNA measurement of metastasis for diagnostic testing. Read the rest of this entry »