Stepwise Adsorption on Single-Wall Carbon Nanotube Networks: Towards Development of Drug Delivery System
General Material Designation
[Thesis]
First Statement of Responsibility
Jin, Sumin
Subsequent Statement of Responsibility
Islam, Mohammad F.
.PUBLICATION, DISTRIBUTION, ETC
Name of Publisher, Distributor, etc.
Carnegie Mellon University
Date of Publication, Distribution, etc.
2021
GENERAL NOTES
Text of Note
170 p.
DISSERTATION (THESIS) NOTE
Dissertation or thesis details and type of degree
Ph.D.
Body granting the degree
Carnegie Mellon University
Text preceding or following the note
2021
SUMMARY OR ABSTRACT
Text of Note
Single-wall carbon nanotubes (SWCNTs) have been increasingly being investigated for biomedical applications including imaging, sensing, and drug delivery. Individual dispersion and coating of SWCNTs with biocompatible molecules are essential to avoid cytotoxicity in the cells and to realize the above listed applications. Perhaps, the most common method for generating SWCNT-based drug delivery system is individually dispersing SWCNTs in aqueous solutions with various biocompatible dispersants, such as DNA, biopolymers, and proteins, via ultrasonication, followed by covalently or noncovalently functionalizing the individual nanotubes with therapeutic molecules and targeting moieties. Another relatively less frequently exploited approach is individually dispersing SWCNTs with the dispersants that have been modified to carry therapeutic molecules. Unfortunately, both approaches suffer from low SWCNT dispersion yield and inadequate control over the drug loading process, particularly, if the drugs are practically insoluble in aqueous solutions, which is the case for most highly potent drugs. We have developed an extremely facile method to generate SWCNT-based drug delivery systems by decorating therapeutic molecules and biocompatible excipients in a controlled manner on preformed SWCNTs networks. We first individually dispersed SWCNTs in water using a suitable type of surfactant molecules, concentrated the SWCNTs/surfactant dispersion to form freestanding networks of SWCNTs, then removed the surfactants from the network. The surfactant-free SWCNT hydrogels comprise of three-dimensional, isotropic network of individual nanotubes held together via van der Waals interactions at the junctions between nanotubes, and have >99% porosity, which allows for unimpeded transport of biocompatible molecules and small drugs. Furthermore, since many potent drugs are only soluble in non-aqueous solvents, water in the SWCNTs networks can be easily exchanged with other suitable solvent systems to facilitate drug loading while preserving their stability. We coated individual SWCNTs within the networks with multiple layers of different molecules, including biocompatible polymer, drugs, and surfactant proteins then dispersed the networks in water through sonication with little or no loss of SWCNT mass from bundling, enabling highly concentrated solution of SWCNTs/drug complexes. Optical characterizations and imaging show that the SWCNTs/drug complexes are individually dispersed and readily taken up by the cells. Cell viability assay confirmed better control over administered drug dose-dependent response and better therapeutic efficacy above the solubility limit of drugs with our SWCNT-based system. In addition, addition of sacrificial, yet assistive, biocompatible polymer layer specificity of drug release in anticancer environment. Overall, our approach allows precisely controlled, stepwise molecular self-assembly on SWCNTs of any drug and biomolecule combinations, suggesting high potential for development of multifunctional drug delivery platforms utilizing SWCNTs.