Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Injectable ‘Smart Sponge’ Holds Promise for Controlled Drug Delivery

In this image, the “smart sponges” are exposed to high glucose levels and are swelling to release insulin. Image: Zhen Gu
In this image, the “smart sponges” are exposed to high glucose levels and are swelling to release insulin.

Image: Zhen Gu

Abstract:
"Glucose-Responsive Microgels Integrated with Enzyme Nanocapsules for Closed-Loop Insulin Delivery"

Authors: Zhen Gu, North Carolina State University and the University of North Carolina at Chapel Hill; Tram T. Dang, Minglin Ma, Benjamin C. Tang, Yizhou Dong, Yunlong Zhang, and Daniel G. Anderson, MIT and Children's Hospital Boston; Hao Cheng and Shan Jiang, MIT

Published: July 8, ACS Nano

DOI: 10.1021/nn401617u

Abstract: A glucose-responsive closed-loop insulin delivery system represents the ideal treatment of type 1 diabetes mellitus. In this study, we develop uniform injectable microgels for controlled glucose-responsive release of insulin. Monodisperse microgels (256 +/= 18 ?m), consisting of a pH-responsive chitosan matrix, enzyme nanocapsules, and recombinant human insulin, were fabricated through a one-step electrospray procedure. Glucose-specific enzymes were covalently encapsulated into the nanocapsules to improve enzymatic stability by protecting from denaturation and immunogenicity as well as to minimize loss due to diffusion from the matrix. The microgel system swelled when subjected to hyperglycemic conditions, as a result of the enzymatic conversion of glucose into gluconic acid and protonation of the chitosan network. Acting as a self-regulating valve system, microgels were adjusted to release insulin at basal release rates under normoglycemic conditions and at higher rates under hyperglycemic conditions. Finally, we demonstrated that these microgels with enzyme nanocapsules facilitate insulin release and result in a reduction of blood glucose levels in a mouse model of type 1 diabetes.

Injectable ‘Smart Sponge’ Holds Promise for Controlled Drug Delivery

Raleigh, NC | Posted on July 18th, 2013

Researchers have developed a drug delivery technique for diabetes treatment in which a sponge-like material surrounds an insulin core. The sponge expands and contracts in response to blood sugar levels to release insulin as needed. The technique could also be used for targeted drug delivery to cancer cells.

"We wanted to mimic the function of health beta-cells, which produce insulin and control its release in a healthy body," says Dr. Zhen Gu, lead author of a paper describing the work and an assistant professor in the joint biomedical engineering program at North Carolina State University and the University of North Carolina at Chapel Hill. "But what we've found also holds promise for smart drug delivery targeting cancer or other diseases." The research team includes Daniel Anderson, the senior author and an associate professor of chemical engineering and member of the Koch Institute for Integrative Cancer Research at MIT, and researchers from the Department of Anesthesiology at Boston Children's Hospital.

The researchers created a spherical, sponge-like matrix out of chitosan, a material found in shrimp and crab shells. Scattered throughout this matrix are smaller nanocapsules made of a porous polymer that contain glucose oxidase or catalase enzymes. The sponge-like matrix surrounds a reservoir that contains insulin. The entire matrix sphere is approximately 250 micrometers in diameter and can be injected into a patient.

When a diabetic patient's blood sugar rises, the glucose triggers a reaction that causes the nanocapsules' enzymes to release hydrogen ions. Those ions bind to the molecular strands of the chitosan sponge, giving them a positive charge. The positively charged chitosan strands then push away from each other, creating larger gaps in the sponge's pores that allow the insulin to escape into the bloodstream. In type 1 and advanced type 2 diabetes, the body needs injections of insulin, a hormone that transports glucose - or blood sugar - from the bloodstream into the body's cells.

As the insulin is released, the body's glucose levels begin to drop. This causes the chitosan to lose its positive charge, and the strands begin to come back together. This shrinks the size of the pores in the sponge, trapping the remaining insulin.

While this work created hydrogen ions by using enzymes that are responsive to glucose, the technique could be simplified to target cancers by eliminating the enzymes altogether. Tumors are acidic environments that have high concentrations of hydrogen ions. If the sponge reservoir were filled with anticancer drugs, the drugs would be released when the chitosan came into contact with the hydrogen ions in tumor tissues or cancer cells.

"We can also adjust the size of the overall ‘sponge' matrix as needed, as small as 100 nanometers," Gu says. "And the chitosan itself can be absorbed by the body, so there are no long term health effects."

In tests using diabetic laboratory mice, the researchers found the sponge matrix was effective at reducing blood sugar for up to 48 hours. However, the researchers published a separate "smart system" for insulin delivery in May that maintained normal blood sugar levels for 10 days.

"But we learned a lot from the promising ‘sponge' research and will further optimize it. Meanwhile, we are already exploring applications to combat cancer," Gu says.

The paper, "Glucose-Responsive Microgels Integrated with Enzyme Nanocapsules for Closed-Loop Insulin Delivery," is published online in ACS Nano. The research was supported by a grant from the Leona M. and Harry B. Helmsley Charitable Trust Foundation, and a gift from the Tayebati Family Foundation.

####

For more information, please click here

Contacts:
Matt Shipman

919-515-6386

Copyright © North Carolina State University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Download article:

Related News Press

News and information

Berkeley Lab Researchers Demonstrate First Size-based Chromatography Technique for the Study of Living Cells April 22nd, 2014

PETA science consortium to present hazard testing strategy at nanotoxicology meeting: High tech field ripe for use of sophisticated non-animal testing strategies April 22nd, 2014

Harris & Harris Group Notes the Receipt of Proceeds From the Sale of Molecular Imprints' Semiconductor Business to Canon April 22nd, 2014

National Space Society Congratulates SpaceX on the Success of CRS-3 and the First Flight of the Falcon 9R April 22nd, 2014

Nanomedicine

Cloaked DNA nanodevices survive pilot mission: Successful foray opens door to virus-like DNA nanodevices that could diagnose diseased tissues and manufacture drugs to treat them April 22nd, 2014

Berkeley Lab Researchers Demonstrate First Size-based Chromatography Technique for the Study of Living Cells April 22nd, 2014

Amino-functionalized carbon nanotubes act as a carrier for nerve growth factor April 21st, 2014

Newly-Produced Bone Cement Able to Carry Medicine April 21st, 2014

Discoveries

Like a hall of mirrors, nanostructures trap photons inside ultrathin solar cells April 22nd, 2014

Nanomaterial Outsmarts Ions April 22nd, 2014

Vacuum Ultraviolet Lamp of the Future Created in Japan: First Solid-State Vacuum UV Phosphor, Described in APL-Materials, Promises Smaller, Safer, Longer Lasting, Low Power Lamps for Industrial Applications April 22nd, 2014

Berkeley Lab Researchers Demonstrate First Size-based Chromatography Technique for the Study of Living Cells April 22nd, 2014

Announcements

Berkeley Lab Researchers Demonstrate First Size-based Chromatography Technique for the Study of Living Cells April 22nd, 2014

PETA science consortium to present hazard testing strategy at nanotoxicology meeting: High tech field ripe for use of sophisticated non-animal testing strategies April 22nd, 2014

Harris & Harris Group Notes the Receipt of Proceeds From the Sale of Molecular Imprints' Semiconductor Business to Canon April 22nd, 2014

National Space Society Congratulates SpaceX on the Success of CRS-3 and the First Flight of the Falcon 9R April 22nd, 2014

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals

Nanomaterial Outsmarts Ions April 22nd, 2014

Vacuum Ultraviolet Lamp of the Future Created in Japan: First Solid-State Vacuum UV Phosphor, Described in APL-Materials, Promises Smaller, Safer, Longer Lasting, Low Power Lamps for Industrial Applications April 22nd, 2014

Berkeley Lab Researchers Demonstrate First Size-based Chromatography Technique for the Study of Living Cells April 22nd, 2014

Nanoreporters tell 'sour' oil from 'sweet': Rice University's hydrogen sulfide nanoreporters gather intel on oil before pumping April 22nd, 2014

Grants/Awards/Scholarships/Gifts/Contests/Honors/Records

National Space Society Congratulates SpaceX on the Success of CRS-3 and the First Flight of the Falcon 9R April 22nd, 2014

Energy Research Facility Construction Project at Brookhaven Lab Wins U.S. Energy Secretary's Achievement Award April 16th, 2014

IDTechEx Printed Electronics Europe 2014 Award Winners April 1st, 2014

Dais Analytic Wins SBIR Grant: Dais Analytic Receives US Army Small Business Innovation Research Grant to Further Its Demonstrated Successes in Cleaning Most Forms of Wastewater March 28th, 2014

NanoNews-Digest
The latest news from around the world, FREE







  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE