Controllable Drug Release Using Graphene Based Nanomaterials

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While cancer is able to be targeted, only some mechanisms are known. Once there is a greater understanding, then this could be used clinically to find a treatment for a variety of tumors. There is a lack of research in methods of controlling drug release; therefore, a more in-depth look was done to see the means of controlling drug release. It was found that drug release could show responsiveness to external stimuli including temperature, pH, ionic concentrations, light, magnetic fields, electric fields, and chemicals (. Some methods of controlling drug release were studied in depth including electrostatically controlled drug release, electrochemically controlled drug release, pH controlled drug release.

Research Method

Using databases supplied by the University of Bridgeport, a wide variety of journals were obtained including Nature, Journal of Controlled Release, Carbon, Journal of Controlled Released, Biomaterials, and many more. Combining prior research lead to “developing new theoretical insights (.” Following LePine and Wilcox-King’s centric research approach, “existing theory and research” was reviewed and further analyzed (. The research focus currently is on finding novel techiniques to control drug delivery. Using prior stuides, a syntehsis of all current research is compilied that will “advance our understanding (.” Controllable drug research is thoroughly investigated. Then it is attempted to be understand through the use of graphene based nanoparticles as well as means of controlling it including electrostatic/electrochemical control as well as pH control.

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Controllable Drug Research using Graphene Based Nanomaterials

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Figure 2: Controllable Drug Release Model detailing the various factors that were further studied.

Controlling drug release could cause a significant amount of advances in therapeutic treatments. Drug release could be controlled by what it is made of such as graphene nanomaterials, the crosslinked materials, or hydrogels. It can also be controlled by electrochemical or electrostatic forces as well as pH. This is conceptualized in figure 2 above.

Graphene Based Nanoparticles

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Figure 3: The various factors that in turn affect graphene based nanomaterials.

As shown in the schematic above, graphene based nanomaterials are directly related to hydrogels and what other agents are in said hydrogel. The materials that compose this hydrogel can crosslink with graphene and when optimized can create a powerful drug delivery mechanisms. Some common crosslinking agents are chitosan and polyethylene glycol (PEG).

Electrostatic/ Electrochemically Controlled Release

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Figure 4: A schematic of prior research, the benefits of using graphene, and the potential applications of electrochemical/Electrostatic Controlled release.

As figure 4 details, prior research has been completed but not in terms of drug delivery and as can be seen in future applications, the possibilities are endless. If a breakthrough is made on this technology, the potential is endless for future uses. This schematic also detailed the benefits of using graphene with an electricity source. A variety of articles are described in the results section on page 13-14.

pH Controlled Release

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Figure 5: A schematic of the pH changes that can affect the body.

This diagram shows what conditions such as inflamed tissues, wounds, external tumors, or just normal body conditions show a change in pH. This change in pH could theoretically be targeted and would allow us to control drug release at these points.

Result and Discussion

Graphene Based Nanomaterials

Graphene’s wondrous two-dimensional material make it a great choice when discussing drug delivery. While the mechanisms of graphene alone make it a great choice, there are some issues regarding graphene. When a graphene hydrogel was made via a hydrothermal process, good results were not seen. When graphene was mixed with an organic solvent, graphene oxides concentration increased greatly (. In other research when PAM was added to a hydrogel it modified the mechanical and thermal properties making it more conducive for drug delivery systems (Shen et al., 2012). PAM was then crosslinked with BIS but it was found to be weak and brittle. When BIS and GO were crosslinked, good tensile properties were found as can be seen in the microstructure shown in the SEM images below. When graphene was added there was a reduction in pore size as well as an expansion in the gel matrix. Another researcher looked at a graphene PAA hydrogel (. It was found to cross link successfully and have potential for a drug delivery system. Graphene Oxide Hydrogels that were crosslinked were looked into further. A study by Goenka further summarized a variety of crosslinked agents and the results of said research and can be seen listed in the table below (Goenka et al., 2014).

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Figure 6: SEM Images of various gels (a) BISI-gel, (b) GO1–BIS1-gel, (c) GO2–BIS1-gel, (d) and GO3–BIS1-gel (Shen et al., 2012).

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Table 1: Drug Delivery and Gene Delivery Applications of graphene Based Nanocomposites (Goenka et al., 2014).

Electrostatic/Electrochemical Controlled Release

Prior ways of drug delivery have been established using an electrochemical control. One such way is detailed by Teymoori and Abbaspour-Sani (. They created a novel electrostatic pump. In this pump, an input and output port, along with three membrane vales, three electrostatic activation systems, and many micro channels were cable of delivering drugs. The means of this pump are detailed in figure 7 below. This pump was thought to work along with the peristaltic motion. It was shown to be successful in theory however no clinical trials have yet to been performed. If instead of a pump it was able to be condensed into an oral drug delivery system then patients could be treated constantly. Reyderman