This presentation describes a novel idea of using carbon nanotubes for targeted drug delivery of the interleukin, IL-10, for Type 1 Diabetes. Reasons for selection and design, with a statement of unmet need, are also listed.

1. Insulin-dependentType1 DiabetesMellitus
(IDDM): CarbonNanotubesdeliveringInterleukin-
10 toTargetedBeta-Cells
Brandon, Dharma, Andrew

2. Background/Description of problem
• Insulin deficiency secondary to pancreatic beta-cell destruction
o T-cell mediated autoimmune attack
• Chronic disorder that often begins early in life
• Susceptibility is largely inherited
o Depends mainly on HLA genotype
• Incidence increasing at 2-5% per year worldwide[11]
• Trend toward decreasing age at presentation

3. Analysis of currently available treatments
• Insulin Injections
o Most common treatment, requires daily insulin injections to regulate blood-
glucose levels
• Pancreas Transplantation
o Reserved for severe cases, essentially a ‘cure’ although has many side effects
associated with transplantation
• Islet Beta-Cell Transplantation
o Injecting cells through catheter, still considered to be experimental since not
therapeutic
o Biomaterial microencapsulation of islet cells - must be replaced every 5-9
months, not consistently successful in large animal models

4. Current Immunomodulators
• Immunomodulators
o Azathioprine
 Acts as an immunosuppressive, inhibiting T-cell response to antigens
 Paired with glucocorticoids in study of 46 patients, only 3 patients
remained in remission at one year, it should be noted equally
discouraging results were produced in a second study
o Mycophenolate Mofetil
 Inhibits proliferation of both T/B-lymphocytes
 Paired with daclizumab, 126 patient study showed neither MMF alone
or in combination with daclizumab slowed Beta-cell destruction in T1D
patients

5. Description of proposed design
• Single-walled carbon nanotubes (SWCNTs)
• Functionalized with:
o Antibodies to beta-cell specific surface receptors
o PEG
o Active peptide fragment of IL-10
• IL-10 linked to PEG via acid-labile bond

6. Schematic
Anti-GPR44 antibody
IL-10

7. Justification of proposed design
• SWCNTs - large surface area to volume ratio for
functionalization[14]
• Functionalized with:
o Antibodies - for specific targeting of β-cells
o PEG - for solubility in aqueous conditions and preventing
cellular uptake
o IL-10 - promote M2 macrophage polarization[5]
• IL-10 release is self-regulatory

8. Synthesis&acid-hydrolysisofPEG-IL-10conjugate[12]
1. Hydroxyl on PEG can be converted to active ester using chloroformate
2. Primary amine groups on Interleukin-10 react with the activated PEG
3. PEG-IL-10 conjugate degrades in acidic pH to release IL-10[13]
The reaction mechanism above was proposed for IL-2[12] and we assume a similar chemical reaction with IL-
10 is plausible (IL-2 and IL-10 are proteins and consist of primary amine groups).

9. Mathematical model
• When CNTs enter the bloodstream, they circulate before getting cleared.
• The fraction of CNTs that reach the pancreatic vasculature and bind to the β-cells is
assumed to be ‘f’. f can be found through fluid transport simulations and
experiments, which is not dealt here.
• Once bound, IL-10 is released via acid-hydrolysis of the amide bond. This can be
modeled as follows.
a. Assumption 1: pH (or [H+]) linearly related to degree of inflammation and
doesn’t change/changes very slowly with time
b. Assumption 2: all CNTs present in the environment are bound (zero order)
Rate of dissociation/IL-10 release rate is given by:
(‘a’ can be determined by measuring kH at two different pHs)

10. Release Profile
time time
[IL-10]
[IL-10]
When [H+] (inflammation) decreases with
increase in [IL-10]
When [H+] doesn’t change with time
(Assumption 1) – the slope increases with
increase in inflammation (given by [H+]) from
Assumption 2

11. Improvement over existing technologies
• Azathioprine is non-specific, making the individual susceptible to
infection from lowered immune response
• Much less invasive/complicated than pancreatic/islet transplants
respectively
• Lower frequency dosage compared to daily injections

12. References
1. Yu et al. Targeted Drug Delivery in Pancreatic Cancer. Biochim Biophys Acta. 2010 January; 1805(1): 97.
2. Zhang et al. The application of carbon nanotubes in target drug delivery systems for cancer therapies. Nanoscale Research
Letters 2011, 6:555
3. Lindskog et al. Novel pancreatic beta cell-specific proteins: Antibody-based proteomics for identification of new biomarker
candidates. Journal of Proteomics. Volume 75, Issue 9, 17 May 2012, Pages 2611–2620
4. Lu et al. Discrete functions of M2a and M2c macrophage subsets determine their relative efficacy in treating chronic kidney
disease. Kidney Int. 2013 Oct;84(4):745-55. doi: 10.1038/ki.2013.135.
5. Biomed K. Spiller class recording Winter 2013_2/11/2013
6. "Fast Facts." Data And Statistics About Diabetes. American Diabetes Association, Mar. 2013. Web. Feb. 2014.
7. Robertson RP, Davis C, Larsen J, Stratta R, Sutherland DER: Pancreas and islet transplantation for patients with diabetes
mellitus (Technical Review). Diabetes Care, 2000, 23:112-116.
8. Roep et al. Antigen Targets of Type I Diabetes Autoimmunity. Cold Spring Harbor Perspectives in Medicine, 2012, vol. 2.
9. Ann Lardner. The effects of extracellular pH on immune function. Journ. of Leukocyte Biol., 2001, vol. 69 (4), 522-530.
10. Atkinson et al. Type 1 Diabetes (Seminar). Lancet, 2014, vol. 383, 69-82.
11. Daneman, Denis. Type 1 Diabetes. The Lancet. Volume 367, Issue 9513, 11–17 March 2006, Pages 847–858
12. Aldwin, L., Goodson, R., Katre, N., Nitecki, D. E. “Preparation of a polymer/interleukin-2 conjugate”. US4902502A. Feb 20,
1990.
13. Electron-pushing mechanisms: <http://www.chem.wisc.edu/areas/reich/handouts/elecpush/ep-mechanisms.htm>
14. Madani, S. Y., Naderi, N., Dissanayake, O., Tan, A., Seifalian, A. M..A new era of cancer treatment:: carbon nanotubes as
drug delivery tools. Int J Nanomedicine. 2011; 6: 2963–2979.

13. Q&A session