S-Nitroso-N-acetylpenicillamine Impregnated Latex: A New Class of Barrier Contraception for the Prevention of Intercourse-Associated UTIs

Abstract

Urinary tract infections (UTIs) are some of the most common infections seen in humans, affecting over half of the female population. Though easily and quickly treatable, if gone untreated for too long, UTIs can lead to narrowing of the urethra as well as bladder and kidney infections. Due to the disease potential, it is crucial to mitigate the development of UTIs throughout healthcare. Unfortunately, sexual activity and the use of condoms have been identified as common risk factors for the development of sexually acquired UTIs. Therefore, this study outlines a potential alteration to existing condom technology to decrease the risk of developing sexually acquired UTIs using S-nitroso-N-acetylpenicillamine (SNAP), a nitric oxide (NO) donor. Herein, varying concentrations of SNAP are integrated into commercialized condoms through a facile solvent swelling method. Physical characterization studies showed that 72–100% of the ultimate tensile strength was maintained with lower SNAP concentrations, validating the modified condom’s mechanical integrity. Additionally, the evaluation of room-temperature storage stability via NO release analysis outlined a lack of special storage conditions needed compared to commercial products. Moreover, these samples exhibited >90% relative cell viability and >96% bacterial killing, proving biocompatibility and antimicrobial properties. SNAP-Latex maintains the desired condom durability while demonstrating excellent potential as an effective new contraceptive technology to mitigate the occurrence of sexually acquired UTIs.

INTRODUCTION

Urinary tract infections (UTIs) affect over 250 million people annually, with over 150 million estimated deaths^{1, 2}. Nearly half of all women will experience at least one UTI requiring antimicrobial therapy during their lifetime³. Compared to men, the increased frequency of UTIs in women is facilitated by the shorter length of the female urinary tract, giving opportunistic pathogens an easier route to infection. Not only are UTIs painful and long-lasting, but an undiagnosed or untreated UTI can lead to life-threatening bloodstream infections. Previous studies have found a positive correlation between sexual activity and the number of UTIs, stating that among sexually active women, most diagnosed UTIs are acquired through sex⁴. During sexual intercourse, millions of bacteria can be sourced from the local microenvironment, which can then adhere to the outer surface of condoms, risking bacterial translocation to the partner’s bodies. These bacteria can come from unwashed hands, oral sex, or, most frequently, from the vaginal and anal openings^{5, 6}. The most prevalent bacterial strain that causes UTIs is the common gastrointestinal bacteria, Escherichia coli (E. coli), causing 90% of all female UTIs⁷. Other strains of bacteria often found on the surface of the skin, namely Enterococcus faecalis (E. faecalis), Staphylococcus aureus (S. aureus), and Staphylococcus saprophyticus (S. saprophyticus), are also frequent contributors to UTI development in women⁸.

Within recent years, there have been breakthroughs in materials science and sexual health to target these risks. Commercially available urinary catheters have been modified with polydopamine⁹, metal nanoparticles^{10, 11}, and S-nitrosothiols¹², creating antimicrobial urinary catheters to decrease the potential of UTI onset. Additionally, sexual health professionals are beginning to understand the correlation between sexual activity and condom use with UTI development in women⁸. However, contemporary condom technology has remained essentially unchanged. While condoms are commonly used to protect from pregnancy and sexually transmitted infections, the most frequently seen issue of UTIs remains untargeted. Often, condom brands lubricate their condoms with Nonoxynol-9 (N-9), a nonionic surfactant widely known for its spermicidal properties¹³. However, including these spermicides has been shown to kill healthy microflora, increase the likelihood of genital irritation, and lead to UTI or yeast infection development post-coitus^{6, 14–17}. The combination of bacterial translocation and spermicide inclusion makes existing condom technology hazardous to its users and calls for more targeted advancements in prophylactic healthcare.

Nitric oxide (NO) is an endogenous free radical that has been researched extensively since its Nobel Prize-winning discovery as a multifunctional molecule that plays a role in the cardiovascular, nervous, and immunological systems¹⁸. A promising characteristic of NO is its role in the immune system as a well-established antimicrobial. As a potent antibacterial, NO has been shown to deaminate DNA and cause nitrosative and oxidative damage when introduced at high concentrations, leading to toxicity for invading microbes¹⁹. This antimicrobial activity can mitigate the rate of device-associated infections by incorporating NO donors, such as S-nitrosothiols (RSNOs), into medical-grade polymers. RSNOs are a class of organic NO-donors that can decompose to release NO through various triggers, including heat, light, and metal ion-initiated release^{20, 21}. Early classes of NO donors, such as organic nitrates and nitrites, have disadvantages in half-life and storage abilities; synthetic donors, such as S-nitroso-N-acetylpenicillamine (SNAP), have been further developed to mitigate these issues²². Due to SNAP’s structure and overall conformation specifically, it has been reported to be stable with an increased half-life and decreased susceptibility to light decomposition compared to other RSNOs and organic NO-donors^{22, 23}.

In addition to its role within the immune system, NO also has a prominent position within the reproductive system. In fact, the expression of nitric oxide synthase (NOS) in genital tissue is promoted by estrogen and testosterone; NOS activity has also been proven to be a potent vasodilator in clitoral and penile tissue, positively influencing erection^24–26. Additionally, previous studies have found that the presence of SNAP can lead to sperm toxicity and decreased sperm motility, removing the need for spermicides within condom lubricant²⁷. Due to thorough characterization and exceptional stability, SNAP has been successfully swelled into multiple medical-grade polymers, such as silicone²⁸, polyvinyl chloride²⁹, and recently within latex-based polymers^{12, 30, 31}. Unlike polymer extrusion done in high temperatures³², an appealing characteristic of impregnation is that it is completed at room temperature. Process completion at room temperature serves as an advantage by reducing the levels of SNAP decomposition, ultimately allowing for stable and prolonged release of NO from the polymer matrix. Furthermore, SNAP incorporation via solvent swelling can be used with already established materials making large-scale material fabrication simple and efficient.

This study incorporated commercially available latex condoms with SNAP using a single-stage solvent-swelling method. The loading efficacies of differing SNAP concentrations (10–25 mg ml⁻¹) were optimized through SNAP leaching, SNAP loading, and NO-release studies. Extensive in vitro analyses were explored to determine toxicity levels toward human testicular cells and overall antibacterial potency in a contact-based method against E. coli and S. aureus. The storage stability of the material was evaluated after three months at room temperature to determine if any special storage conditions were needed for this new material. The resulting NO-releasing latex (SNAP-Latex) condoms show promise as a broad-spectrum solution to intercourse-related urinary tract infections.

2.0. EXPERIMENTAL

2.1. Materials

Fibroblast cells (ATCC CRL-2522) harvested from human foreskin (BJ cells) along with various bacterial strains: Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 6538) were obtained through the American Type Culture Collection (Manassas, VA). S-nitroso-N-acetylpenicillamine was purchased from PharmaBlock (Hatfield, PA). Cell culture media made-up of Dulbecco’s Modified Eagle Medium (DMEM), fetal bovine serum (FBS), and penicillin-streptomycin was obtained by Fisher Scientific, VWR, and Fisher Scientific, respectively. Cell Counting Kit-8 (CCK-8) was obtained through VWR. All other chemicals used: methanol, phosphate buffer saline (PBS), ethylenediaminetetraacetic acid (EDTA), Luria Bertani (LB) broth and agar, and tetrahydrofuran (THF) were purchased from Sigma-Aldrich (St. Louis, MO). Lubricated Trojan ENZ latex condoms were purchased from CVS Pharmacy (Athens, GA). 18.2 MΩ deionized water was prepared locally with a distillation unit from Mettler Toledo (Columbus, OH USA). Nitrogen, oxygen, and carbon dioxide gas tanks were purchased from Airgas (Kennesaw, GA USA). All cell culture and bacterial culture experiments were completed within a BSL level 2 facility approved by the University of Georgia.

2.2. Methods

2.2.1. Integration of SNAP

2.2.1a. Swelling of latex condoms

Commercially available latex condoms were washed with soap and warm water and air dried to remove any lubricant that may interfere with the ability of SNAP to integrate into the polymer. Once completely dried, an 8 mm biopsy punch was used to stamp out circular samples (1.0 cm²). The biopsy samples were submerged in solutions of either 10, 15, or 25 mg ml⁻¹ of dissolved SNAP using THF as the solvent; the samples were left to swell, protected from light with gentle rocking. After 24 h, the samples were removed from the swelling solution and dried at room temperature in the dark overnight. Any crystallized SNAP on the surface of the samples was removed by gentle agitation in deionized water. Once completely dried, the SNAP-swelled latex was stored at −20ºC before further testing as suggested by previous literature³³.

2.2.1b. Characterizing the amount of SNAP within the samples

A SNAP loading study was completed to determine how much SNAP was swelled into each sample. Individual samples were entirely submerged in THF and left at room temperature while protected from light for 1–2 h. Once the sample cutouts were completely translucent, the THF solution’s absorbance was measured in the 200–800 nm range to detect the characteristic RSNO peak at 340 nm³⁴ using a Genesys 10S UV-Vis Spectrometer (Thermo Scientific). A THF-SNAP standard curve was then used to determine the final SNAP concentration swelled into each sample.

A separate leaching study was performed to analyze the amount of SNAP that leaches out of the samples when placed in physiological conditions (submerged at 37ºC, dark, 5% CO₂)^{35, 36}. For this, the samples were immersed in PBS at 37ºC for up to 4 h. At each time point, the absorbance of the PBS was detected using UV-Vis. For data analysis, a PBS-SNAP standard curve was used. First, the mass of SNAP is calculated from the detected optical density using the standard curve. It is then compared against the level of SNAP loaded into the samples to get the final percentage of SNAP leached into the solution (Fig. S1).

2.2.2. Tensile testing

The utility of condoms is entirely based on their mechanical integrity; completion of an ultimate tensile strength (UTS) test serves to evaluate the potential negative impacts of SNAP swelling. Using a Mark-10 Force and Tensile Measurement System (Copiague, NY), 4×1 cm samples (gauge length 3 cm) with average thickness of 0.076 ± 0.006 mm of the varying SNAP-Latex and control latex (n≥4) were subjected to an increased load at a rate of 5 inches min⁻¹ until breaking. The numerical load at each break was normalized to the gauge area to calculate the final UTS.

2.2.3. Nitric oxide release analysis and storage stability

2.2.3a. Submerged Conditions

Nitric oxide release from the SNAP-Latex was measured using chemiluminescence-based detection from a Sievers Nitric Oxide Analyzer (NOA) model 280i (Boulder, CO). The circular samples were submerged in 2 mL of 10 mM PBS + 100 µM EDTA inside an amber glass collection vial heated to 37ºC by a circulating water bath. A dry nitrogen purge stream with a flow rate of approximately 200 cm³ min⁻¹ was swept into the PBS containing the SNAP-Latex sample. Any nitric oxide being emitted from the sample is then swept into the reaction chamber of the NOA where it reacts with ozone to form nitrogen dioxide in its excited state. The relaxation of the nitrogen dioxide results in photoemission detected within the NOA and is output as a measurement of NO amount in parts per billion (PPB). These values can then be calculated as moles of NO cm⁻² sec⁻¹ using the NOA constant (mol NO/PPB x sec). These samples were measured for 4 h each (n=4) to mirror the studies completed within the antibacterial testing (2.2.4) (Fig. S2).

2.2.3b. Moist Conditions

NO release analysis of the SNAP-Latex was also performed in moist conditions to increase application relevance. The samples were individually wrapped in Kimwipes and tied with twine for this study. The pouches containing the latex samples were then dampened using 100 µL of 10 mM PBS + 100 µM EDTA and suspended above 2 mL of the same PBS solution while nitrogen gas was swept into the amber vial. The exact process applies as detailed above regarding the reaction within the NOA. For these studies, because the application period for condom use is relatively short, the samples were analyzed for 60 min before being removed from the chamber. However, the storage life of condoms is known to be quite long; therefore, the storage stability of this SNAP-Latex was also measured. Samples were stored at room temperature under dark conditions for up to 3 months before being analyzed periodically on the NOA in moist conditions.

2.2.4. In vitro Analysis of SNAP-Latex

2.2.4a. Cell Viability of Human Fibroblast Cells

All cell viability experimentation with the SNAP-Latex samples was completed in compliance with ISO 10993–5 biocompatibility testing standards for medical devices³⁷.

BJ cells obtained through the ATCC were revived from cryopreservation and cultured in DMEM media supplemented with 1% penicillin-streptomycin (P/S) solution and 10% fetal bovine serum (FBS) under a 5% CO₂-humidified atmosphere at 37ºC. Cells were subcultured a minimum of three times before being used in any experimentation. Subculturing occurred once the cells grew to >70% confluency; procedures consisted of washing the cell monolayer with PBS before detaching the cells using 0.25% Trypsin + 0.5 mM EDTA. Once cells were fully suspended, the flask was washed to obtain a single-cell suspension using cell culture media to stop the trypsin reaction, detach any residual cells, and break up any clumps of cells in the solution. A certain volume of cells was reseeded into the culture flask for later use.

When seeding plate inserts, the detached cells were stained with trypan blue dye to be counted using an EVE cell counting system from NanoEnTek (Waltham, MA). The cells were seeded into 6.5 mm cell culture plate inserts at 10,000 cells per insert and grown for 24 h to achieve confluency. The cells were exposed to the SNAP-Latex and control films by adding the films directly into the culture wells below each insert along with 700 µL of culture media. The media atop the cells was also changed at the time of sample exposure. The samples were left within the culture media for 4 h under physiological conditions (37ºC, dark, 5% CO₂) before clean media supplemented with 10% CCK-8 reagent was added to the inserts containing the cells. CCK-8 is a tetrazolium salt-based colorimetric assay that detects the metabolic activity of cells. Viable cells can cleave the salt to create formazan, changing the solution to orange. Formazan levels are detected through its absorbance of light at 450 nm. Cells were incubated with the CCK-8 for 1 h at 37ºC and 5% CO₂ before being read for absorbances at optical densities of 450 and 650 nm. Determination of BJ cell viability occurred by comparing absorbance values from the control samples with the SNAP-Latex using the following equation.

$$Relative\mathrm{ }Cell\mathrm{ }Viability\mathrm{ }\left(\mathrm{\%}\right)=\frac{{\left(O{D}_{450}read\mathrm{ }-\mathrm{ }O{D}_{650}read\right)}_{Test\mathrm{ }group}}{{\left(O{D}_{450}read\mathrm{ }-\mathrm{ }O{D}_{650}read\right)}_{Control\mathrm{ }group}}X\mathrm{ }100\mathrm{ }\mathrm{ }$$

2.2.4b. Antibacterial Testing

The antibacterial application of NO released from our SNAP swelled samples compared to control latex samples was tested using 24 h bacterial adhesion testing. The bacterial solution was prepped by isolating a single colony of S. aureus or E. coli into LB broth before being incubated and shaken at 37ºC and 150 rpm to achieve log phase growth. After reaching the log phase of growth, the bacteria were centrifuged, rinsed with PBS, and then resuspended in PBS. Using an optical density measurement taken via UV-Vis, bacteria were diluted to a starting concentration of ~10⁸ CFU mL^-1. The films were first sterilized using UV light for 30 minutes before submerging them in the 10⁸ CFU ml⁻¹ bacterial solution. The samples underwent an incubation period of 24 h under the aforementioned conditions. After incubation, samples were briefly rinsed with PBS, homogenized, vortexed, and then plated onto LB agar plates. After 16–24 h of incubation, plates were removed, and colony-forming units (CFUs) were counted. The reduction of adhered bacteria was calculated for all samples using the equation below. Final data is reported as the mean number of colony-forming units per surface area (CFU cm⁻²) ± SD (n=4).

$$Reduction\mathrm{ }in\mathrm{ }Adhered\mathrm{ }Bacteria\mathrm{ }\left(\mathrm{\%}\right)=\frac{control\mathrm{ }CFU\mathrm{ }c{m}^{-2}-treatment\mathrm{ }CFU\mathrm{ }c{m}^{-2}}{control\mathrm{ }CFU\mathrm{ }c{m}^{-2}}x100$$

2.3. Statistical Analysis

All statistical analyses were performed using Prism 9.1 (GraphPad Software, San Diego, CA) and are reported as mean ± standard deviation (SD) unless otherwise mentioned. Mechanical characterization, storage stability, and cytocompatibility were analyzed using ordinary one-way analysis of variance (ANOVA), with multiple comparisons between sample group averages. All bacteria data were analyzed using two-way ANOVA with the same corrections for multiple comparisons. P values < 0.05 were determined to be significant.

3.0. RESULTS

3.1. SNAP-Latex Material Characterization

3.1.1. Tensile Testing.

The mechanical strength of the modified latex was analyzed to ensure the overall durability of the material remained intact after the integration of SNAP. The ultimate tensile strength (UTS) was determined for three SNAP concentrations (10, 15, and 25 mg ml⁻¹) as well as for the control latex (Fig. 1b). A noticeable decrease in UTS was exhibited in the samples with the highest SNAP concentration, 25 mg ml^-1. The mechanical integrity of the 25 mg ml⁻¹ SNAP (SNAP-25) samples deteriorated by more than half compared to the unmodified control latex, with a UTS around 2 N mm^-2. Due to the severe loss in strength, the SNAP-25 samples were not analyzed throughout the subsequent studies. However, there were no significant differences in the other SNAP-Latex samples compared to the control latex. The control and 10 mg ml⁻¹ SNAP (SNAP-10) samples had an average UTS of ~5 N mm⁻², whereas the 15 mg ml⁻¹ SNAP (SNAP-15) samples showed a slightly lower average UTS of around 4 N mm^-2.

Figure 1.

Total SNAP loading analyzed after 24-hour SNAP-impregnation (a). UTS compared across all sample groups (b). Statistical significance displayed as p < 0.01.

3.1.2. SNAP Loading.

In any SNAP-impregnated material, it is vital to analyze the exact amount of SNAP that has entered the polymer matrix to properly ascertain its contribution to mechanical changes, NO release, and biocompatibility. Determining these SNAP levels involves resubmerging the samples in THF and leaving them at room temperature for 1–2 hours to dissolve any SNAP within the material or on the surface. The SNAP samples showed loadings of 11.6 ± 1.5, 12.7 ± 0.4, and 13.5 ± 1.5 µg SNAP/µg latex (reported as a weight percent) for SNAP-10, SNAP-15, and SNAP-25, respectively (Fig. 1a). There are insignificant increases in the amount of SNAP loaded into the sample groups showing that the latex samples reach their maximum loading capacity with 10 mg/mL of SNAP in the swelling solution.

3.1.3. SNAP Leaching Measurements.

Just as determining the levels of SNAP within the polymer is important, understanding the amount of SNAP that leaches out of the material when placed in physiological conditions aids in determining the material’s longevity and cytocompatibility³⁸. The amount of SNAP was determined using UV-Vis spectroscopy every hour for 4 h (Fig. S1). Despite similar SNAP loading profiles between the two SNAP-Latex groups, the SNAP-15 displayed a significantly higher level of leaching, reaching ~60% by 2 h when the samples plateaued. However, the SNAP-10 had no higher than 30% leaching throughout the incubation period. The leaching variability is potentially due to the latex reaching its maximum loading capacity with excess SNAP introduced at 15 mg ml^-1. In some cases, the SNAP does not fully integrate into the polymer matrix once the polymer’s swelling capacity has been reached. The additional SNAP remains on the surface or slightly within the polymer but is not stabilized in its crystalline form. Regardless of the SNAP-Latex sample, each group displayed a relatively high level of leaching compared to previous studies involving SNAP-impregnation^{12, 39}. A cytocompatibility analysis was completed to determine how the high levels of leaching would contribute to toxicity toward human cells (Fig. 3).

Figure 3.

In vitro evaluation of SNAP-Latex condoms. Cell viability of human fibroblast cells after direct exposure to SNAP-Latex (a). Bacterial adhesion studies after 24 h of exposure time, normalized to the sample surface area (b). Statistical significance is displayed as **: p=0.001, ***: p<0.001 based on two-way ANOVA testing.

3.2. Sustained NO Release and Storage Stability

To understand the storage capacity and sustainability of the NO donor, SNAP, the NO release of the SNAP-Latex samples was analyzed across 3 months (Fig. 2). The samples were kept in routine condom storage conditions (room temperature (20–24ºC), dark) and analyzed for NO release in moist conditions at varying time points. Since condoms are single-use materials, new samples were used at each time point for NO release. As shown in Figure 2, the NO-release stays consistent for the samples across the entire storage timespan. The NO-Flux remains in the range of 20–40 (x10⁻¹⁰ mol min⁻¹ cm⁻²) with minor fluctuations for each SNAP-10 and SNAP-15 group, consistent with previous studies. No statistical significance (p > 0.05) is displayed when comparing NO release across all time points using an ordinary one-way ANOVA analysis. SNAP-Latex films showed little to no significant degradation over a 3-month span when kept in these conditions, proving this novel material’s feasibility to maintain efficacy without any modification to current storage practices of commercial condoms.

Figure 2.

NO release measurements of SNAP-Latex samples across a period of 3 months in condom storage conditions (room temperature, dark). No statistical significance was displayed across any time point.

3.2. In vitro Biocompatibility and Antimicrobial Testing

3.3a. Cytocompatibility Analysis

In developing biomaterials, specifically ones that are effective through the active release of NO, it is beneficial to show that the levels of the released drug are not eliciting additional secondary biocidal effects. As discussed in 3.1.3, the SNAP-Latex samples exhibited higher than normal levels of SNAP leaching across a 4 h period, further necessitating an analysis of cytotoxicity⁴⁰. To this end, SNAP-swelled condom samples were directly exposed to human-derived BJ fibroblast cells following ISO 10993–5 standards³⁷ for detecting cell viability using tissue culture plate inserts for 4 h. The cytocompatibility was then analyzed using a colorimetric CCK-8 reagent. No significant differences between the sample groups were detected, and all samples’ means are above the ISO threshold of cytocompatibility indicated by the dashed line. SNAP has been shown to have a proliferative effect in mammalian cells which can explain the exhibited lack of toxicity shown in the SNAP-15 samples due to the increased leaching. The seemingly high levels of SNAP leaching led to proliferation rather than toxicity, proving that the materials will not negatively interfere with the biological processes of the cells they interact with. This initial biological characterization further supports the continuation of the SNAP-Latex formulation for subsequent studies and potential commercialization.

3.4b. Bacterial Inhibition

A stable release of NO is desired to reduce bacterial growth on the surface. The SNAP-Latex samples were tested against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) to represent Gram-positive and Gram-negative bacteria. These strains also represent the most common bacteria found on the skin’s surface, with E. coli causing up to 90% of female UTIs^{5, 7}. Untreated latex condoms were used as a control to compare against SNAP-Latex samples. Bacterial adhesion studies were completed as they represent the most likely infection scenario concerning condom application and use. There were significant decreases in CFU counts for both S. aureus and E. coli compared to the latex control; 0.73 ± 0.15 and 0.58 ± 0.28 log reductions can be seen in each bacterial strain, respectively, when tested against SNAP-10 and 0.88 ± 0.02 and 1.00 ± 0.02 log reductions are visualized with SNAP-15 (Fig. 3). This data strongly supports the ability of this novel condom material to maintain efficacy throughout extended periods without having to alter any conventional condom storage conditions.

4.0. DISCUSSION

Instances of UTIs obtained through sexual intercourse account for more than 80% of the diagnosed UTIs in sexually active women⁴. Numerous studies have shown the ability of NO embedded into various polymers to kill opportunistic pathogens that cause UTIs^{12, 41}. Here, a commercially sold latex condom was modified to contain an NO donor to facilitate bacterial killing of the same UTI-causing pathogens. Previous studies have shown the integration of NO donors, specifically SNAP, to decrease the overall tensile strength of medical-grade polymers when swelled at higher concentrations⁴². Physical durability is essential to the functionality of a condom to inhibit pregnancy and the spread of sexually transmitted diseases. These results confirm that the integration of low levels of SNAP into a commercial latex condom does not significantly affect the strength of the material and, therefore, maintains the condom’s function.

The NO release profile of the SNAP-Latex was studied over a 3-month period. SNAP has been shown to degrade by almost 60% when stored at room temperature (22–25ºC)⁴³; however, when integrated into the thin latex material, it displayed complete stability. Consistent levels of NO were released for over 80 d in both the SNAP-10 and SNAP-15 samples which was expected due to the loading capacity of the latex peaking at around 10 mg/mL (Fig. 1a). Currently, commercially sold condoms are stored at room temperature in boxes protected from light. Many materials designed with embedded NO donors, such as SNAP, require specialized storage conditions due to SNAP’s degradation rate; however, here, it is shown that the therapeutic effect of this modified condom is not lost when stored in the same manner as current condom technologies. Finally, this modified condom technology exhibited significant bactericidal effects while maintaining high levels of cytocompatibility. No toxicity was shown when placed in direct contact with human cells derived from testicular tissue; therefore, this material would be safe for use on sensitive genital areas.

5.0. CONCLUSIONS

Sexual activity and frequency of UTIs are positively correlated; untreated UTIs in women can lead to pain, narrowing of the urethra, and potentially fatal bladder and kidney infections⁴⁴. This work outlines a potential new development in prophylactic sexual healthcare by improving current condom technology, including the NO donor molecule SNAP. SNAP-swelled latex condoms exhibited their maximum swelling capacity to be ~12 wt% SNAP as all sample groups displayed similar amounts of SNAP loaded into the latex. As such, the SNAP-10 and SNAP-15 outperformed the SNAP-25 due to an extreme decrease in mechanical strength within the condom material caused by excess SNAP degrading the polymer make-up. The latex samples containing lower amounts of SNAP maintained their mechanical integrity and their available NO reservoir for 3 months when stored at room temperature. The consistent release of NO across this extended time period infers the same cytocompatibility and bactericidal effects that will be true after long-term storage. This modified latex condom shows bactericidal capabilities against Gram-positive and Gram-negative bacteria commonly associated with sexually acquired urinary tract infections. Additionally, our materials maintained high ultimate tensile strength, cytocompatibility, and bacterial killing efficiency while expressing the ability to maintain potency throughout long-term storage. This material can further improve contraceptive technologies, decreasing the frequency of sexually derived UTIs.