Discipline: Biological Sciences
Jahniece Williams - Howard University
Co-Author(s): Briana J. Brown, Howard University, Washington, DC Shruthi Shyamala, Temple University, Philadelphia, PA
Controlled drug delivery systems afford the advantages of prolonging delivery, altering the side effects, and optimizing the dosage. Current delivery systems are polymeric, which are less stable, more susceptible to degradation, and rapid elimination of the drug. Mesoporous silica is a more effective agent for drug delivery because it is more biocompatible and has a high surface area, large pore volume, and tunable pore size. SBA-15 is a form of mesoporous silica with a honeycomb-like appearance and hundreds of empty channels called mesopores. The mesopores of SBA-15 can absorb or encapsulate large quantities of bioactive molecules. The tunable pore size is ideal for controlled release. The biocompatibility of SBA-15 affords it low toxicity and a high affinity for phospholipids, which increases its probability for intracellular uptake. For the purpose of this study, SBA-15 is used for controlled drug delivery of amoxicillin to demonstrate that its qualities allow accurate control and timing of drug release. This research is significant because this control is necessary if the drug delivery system is used to deliver toxic drugs that can damage the body if released prematurely.
Two trials of SBA-15 were produced with P-123 triblock copolymer, tetraethyl orthosilycate and 2M HCl. The amount of 2M HCl differed for each trial with Trial 2 SBA-15 containing more HCl. Due to the inert nature of mesoporous silica, its surface must be functionalized in order to serve as a drug delivery system. Surface functionalization improves surface hydrophobicity, allows the control of surface-drug affinity and allows covalent coupling of protein or other biomolecules, such as antibiotics, to the surface. The two trials of SBA-15 were each functionalized with (3-aminopropyl) triethoxysilane (APTES) and N-[3-(Trimethoxysilyl)propyl]-ethylenediamine (TPED), resulting in four different functionalized SBA-15 nanoparticles. Amoxicillin was purified and loaded onto the functionalized and unfunctionalized SBA-15. Each sample of SBA-15 was dissolved in PBS buffer (pH 7) and incubated at 37˚C to simulate bodily conditions and measure the amount of amoxicillin released from the SBA-15 at different time intervals.
The SEM and TEM results showed the distinct mesopores of the SBA-15 samples and suggested a promising drug delivery system. The FTIR results confirmed the loaded and functionalized SBA-15. The next steps would be to create a standard curve for the amoxicillin release and determine the amount of amoxicillin released under simulated bodily conditions. If SBA-15 proves to be an effective drug delivery system, it can potentially be used to deliver toxic anti-tumor drugs and prevent the detrimental effects caused by their premature release.
Funder Acknowledgement(s): This material is based upon work supported by the National Science Foundation under Grant No. HRD-1238466. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
Faculty Advisor: Wayne Patterson,