Figure 1.
Electrospun fibers incorporate drugs for multipurpose prevention.
(a) Two-axis mandrel electrospinning rig for fiber collection. (b) Controlled fiber deposition along a grounded aluminum collector produces a geometry that may be suitable for vaginal drug delivery. (c) Mesh abstracted from mandrel has a hollow interior. (d) Fiber meshes have porous microstructure. (e) Combining fiber meshes produces a multifunctional material. (f) Diverse agents with action against HIV, HSV-2, or sperm are incorporated into blends of PLLA and PEO. PLLA/PEO (30∶70, blue) and PLLA/PEO (70∶30, red); AZT = 1 wt% 3′-azido-3′-deoxythymidine, MVC = 1 wt% maraviroc, ACV = 1 wt% acycloguanosine, GML = 10 wt% glycerol monolaurate, MBCD = 10 wt% methyl-β-cyclodextrin, Fe/Asc = 10 wt% iron (II) D-gluconate with 10 wt% ascorbic acid.
Figure 2.
Fiber composition influences degradation properties.
(a) SEM micrographs show that fiber and mesh morphology changes markedly over 15 d in VFS. (b) Mass loss of fibers over time is controlled by PEO content in fibers. (c) Fiber diameters, displayed as geometric mean with 95% confidence interval, and decrease significantly over three days of degradation in VFS (p<0.0001 for 30∶70 and 70∶30 PLLA/PEO fibers). 30∶70 PLLA/PEO (blue) and 70∶30 PLLA/PEO (red) for (b) and (c).
Figure 3.
Fibers release active antiretroviral agents.
(a) Cumulative drug release in VFS was measured for 30∶70 PLLA/PEO (blue) and 70∶30 PLLA/PEO (red). AZT (dashed line) and MVC (solid line) showed rapid burst release from blended fibers within 1 h. (b) Varying fiber diameter resulted in MVC burst release from PCL fibers (black) and 70∶30 PLLA/PEO fibers (red). PCL meshes with two fiber diameters ( • = 370 nm and ⊥ = 1.3 μm) and 70∶30 PLLA/PEO fibers with three fiber diameters ( • = 560 nm, ○ = 1.5 μm, ⊥ = 3.4 μm) were tested. (c) Sustained release of MVC is achieved from PDLLA/PLLA blends and from 99∶1 PLLA/PEO, but not from PLLA fibers. 50∶50 PDLLA/PLLA (□), 25∶75 PDLLA/PLLA (▪), 99∶1 PLLA/PEO (•), and 100% PLLA (⊥). (d) Insertion of fibers into mouse vagina and subsequent fluorescent imaging reveal release of dye within 30 minutes for ICG-loaded fibers (right) compared with blank fibers (left). Fiber meshes are shown next to excised reproductive tracts.
Figure 4.
Fiber meshes inhibit HIV in vitro and are nontoxic to macaque cervical tissue explants.
(a) Dose-response assay indicates that AZT and MVC released from fibers have similar potency to unformulated drugs (drug eluates, black and unformulated drug, gray). (b) Drug loaded fiber blends (30∶70 PLLA/PEO (blue) and 70∶30 PLLA/PEO (red)), but not blank fiber controls, show equivalent inhibition of HIV infection. (c) Histology indicates that 30∶70 PLLA/PEO, 70∶30 PLLA/PEO, and 30∶70 PLLA/PEO fibers with 10% (wt/wt) GML are nontoxic to macaque cervical tissue explants compared to nonoxynol-9 control. (d) MTT assay confirms fibers, including those containing 10% (wt/wt) GML, are nontoxic to tissue explants. Note that for media controls n = 4, and for all other groups n = 1.
Figure 5.
Fiber meshes are a physical and chemical barrier against sperm.
(a) Motility of human swim-out sperm was completely inhibited within 5 min for 0.05 and 0.5% GML. Data show counts of motile and immotile sperm at 2 min (gray line) and 5 min (black line). Baseline sperm motility (∼89%) was measured at the beginning and end of experiment using a PBS control (dotted line). (b) Sperm viability is reduced in whole semen incubated with GML compared with media control. (c) GML release from fiber meshes was qualitatively measured using TLC. (d, e) A transwell assay was used to test the physical barrier properties of the fiber meshes by replacing Millicell cell culture insert membranes (3 μm pore diameter) with a blank fiber mesh (n = 3). (f, g) SEM micrographs of the upper (f) and lower (g) side of Millicell control membrane. (h, i) SEM micrographs of upper (h) and lower side (i) of fiber mesh show that no sperm penetrate through the fiber mesh.