Date on Master's Thesis/Doctoral Dissertation

12-2019

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Pharmacology and Toxicology

Degree Program

Pharmacology and Toxicology, PhD

Committee Chair

Steinbach-Rankins, Jill

Committee Co-Chair (if applicable)

Frieboes, Hermann

Committee Member

Frieboes, Hermann

Committee Member

Fuqua, Joshua

Committee Member

Matoba, Nobuyuki

Committee Member

Palmer, Kenneth

Author's Keywords

Nanoparticles; electrospun fibers; griffithsin; HIV; microbicide; vaginal delivery

Abstract

Human immunodeficiency virus-1 (HIV-1) and herpes simplex virus 2 (HSV-2) affect hundreds of millions of people worldwide, with women disproportionately impacted by these infections. Currently, only oral pre-exposure prophylaxis (PrEP) is approved specifically for the prevention of HIV-1, but is challenged with adverse side effects associated with long-term use. Topical delivery platforms, such as gels and films, deliver agents directly to the female reproductive tract, but are limited in providing transient-release. The technology of polymeric electrospun fibers may serve as alternative topical delivery platform to the female reproductive tract. In these studies, we fabricated electrospun fibers comprised of different polymers or polymer blends that possess different physical attributes and fiber architectures. The goal was to provide sustained-release of agents such as the antiretroviral tenofovir disoproxil fumarate (TDF) and the antiviral lectin, Griffithsin (GRFT). We hypothesized that these delivery platforms would prevent HIV-1 and HSV-2 infections, while retaining the safety and biocompatibility of free agent. To determine the amount of GRFT loading and release from fiber formulations, ELISA was conducted, whereas TDF quantification was performed using absorbance measurements. Next, the in vitro efficacy of composites was assessed in HIV-1 and HSV-2 infectivity assays. From these initial results, multilayered fiber composites, free NPs, and hydrophilic fibers were tested for safety and antiviral efficacy within a murine model. Animal studies were conducted using 5-week-old female BALB/c mice, histology and cytokine expression were evaluated from mouse reproductive tracts and vaginal lavages collected 24 and 72 hr following platform administration. In parallel experiments, mice were administered fibers, followed by a single challenge 4 or 24 hr later with HSV-2 (LD90). Viral progression was monitored for 14 days post viral challenge to evaluate potential infection. Statistical significance for all studies was determined using one-way ANOVA with Bonferroni post hoc test (p < 0.05), while log-ranked post hoc tests were used for antiviral efficacy studies. Future studies will consider encapsulation of multiple antiviral compounds to provide synergetic protection against infection.

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