BACKGROUND

Initially, our team aimed to take advantage of menstrual blood as a non-invasive blood sample for gynecological diseases screening and focused on gynecological cancers. Later, through surveys and expert interviews, we realized the importance of non-cancerous gynecological disease. Gynecological cancers are deadly, 334,382 deaths were documented from gynecological cancers for women above the age of 25 from 2010 to 2022 in the US alone [1] .But what is causing this high mortality? These female-targeted cancers seem to be fairly curable [2,3]. The major problem that is causing the high mortality rates is late diagnosis [4,5].

Late Diagnosis

Why do late diagnoses happen? Through interviewing Dr. He (refer to our Human Practices page for more details), we learned that gynecological cancers lack noticeable and distinct symptoms in its early stages, making it extremely difficult for women to recognize when they are in the early stages; additionally, standard diagnoses procedures are quite time consuming and expensive, meaning people usually do not get screenings regularly. Menstrual pain, vaginitis, to uterine fibroids, these gynecological diseases of all magnitude have very similar symptoms which usually involve abdominal pain, menstrual disorders, abnormal leukorrhea vaginal discharge, abnormal irregular bleeding that deviates from menstruation from the lower body, and even some may not even have obvious symptoms or no symptoms at all.

In addition to expert interviews, by reviewing published research papers, we learned that despite geological differences, women worldwide do not receive the number of preventive health examinations (PHE) and preventive gynecological examinations (PGE) as recommended. This is a substantial factor for late diagnosis. For instance, data from the United States shows that only 44.4 million or 20.9% of adults receive PHEs and 19.4 million or 17.7% females receive PGEs annually. In other words, 79.1% and 82.3% do not receive PHEs and PGEs as suggested [6]. Moreover, even when they attended these visits, less than half of preventive services were provided during PHEs, and while PGEs are more comprehensive, the coverage of preventive services is still limited. There is a similar trend in Austria. 58.2% of women had never attended a preventive health check-up within the last three years [7]. Education and income level were universal determinants in affecting the examination frequency [6-10].

Residential regions may imply the financial status and level of education of individuals. Women from counties with less than or equal to 10,000 residents and not adjacent to a metropolitan country were less likely to report preventive health examinations [10]. Indeed, by sending out surveys to the public, education and income’s effects were further confirmed (refer to the public survey in the HP section). A third of suburban and rural residents in China exceed the suggested time interval for physical examination (see figure 1). 21.4% of those never actively sought examination. Thus, while many women receive PGEs, a majority do not undergo regular exams as frequently as recommended, and preventive services are underutilized. This indicates a gap between the need for regular preventive care and the actual utilization of such services. More importantly, the data suggests a lack of awareness for gynecological diseases, meaning some women are not aware of the necessity of screenings, or even the existence of such diseases.

Diving deeper into related topics we also realized that cancers are not the only disease that are important, other gynecological diseases such as HPV, also share this nature of being difficult to self-diagnose yet life threatening if diagnosed at a late stage.

It is worth noting that with the popularity of medical check-ups, the huge hidden dangers behind gynecological diseases are gradually becoming apparent. A lot of women suffering from gynecological diseases do not get timely and effective diagnosis and treatment.

The status quo

Currently, the detection and diagnosis of gynecological diseases rely on a few standard methods, each with substantial limitations.

Physical examinations are among the most accurate and comprehensive diagnostic tools available. These include laparoscopy, transvaginal ultrasound, and pap smear. They allow doctors to directly examine the abdomen or pelvis via tiny incisions, pelvic organs, and abnormal cells in the female reproductive organs. However, they can be time-consuming, invasive, and expensive. The pap smear test, for example, requires a 15–20-minute appointment to complete the swab. The doctor first swabs for abnormal discharge. Then, they would insert a speculum to expose the cervix carefully. Finally, they would apply a swab to collect cell samples from the ectocervix. But the time for a pathology laboratory to process the sample and offer the results to one’s doctor can range from 1-3 weeks [11] . Across all facilities, the average cost for a pap smear is $143 [12] . The price can vary based on location and insurance coverage. Most importantly, these examinations require one to actively seek examination. These factors result in women not performing screenings as frequently as medical guidelines suggest.

Lab tests are alternative approaches. Home kits enable women to collect samples and send them to the laboratory for evaluation. Though this method can be less invasive, it still requires active examination, most occurring only after existing symptoms. Furthermore, each lab test is disease-specific, meaning women must classify their symptoms and identify the corresponding disease themselves, which can be a significant barrier to early detection. In fact, for many, the lack of distinct symptoms makes it difficult to recognize when testing is necessary.

Like mentioned, a survey was sent out to the public for further investigation. Six hundred sixty females participated in the survey. Among the participants, the majority were from the age group of 35-44, also known as the maternal age (3.78% were under 18 years old, 8.48% between 18-24, 19.39% between 25-34, 35% between 35-44, 28.03% between 45-54, 4.24% between 55-64, and 1.06% greater than 65). They were from regions around China and predominantly resided in city areas.

Participants recognize regular physical examination is essential by rating a 4.27 on average on a scale from 0 to 5, with 5 being very important. Most, indeed, go for regular health examinations annually (see Figure 2). Health awareness is the most critical factor determining one’s physical examination rate (see Figure 3). It is then followed by study/work pressure, accessibility to medical resources, and financial concerns. This indicates that even if women are aware of their own health, the barriers identified—particularly time constraints, accessibility, and financial concerns— may prohibit many women from seeking testing until symptoms manifest. This delay in diagnosis can contribute to the progression of gynecological diseases, which often remain asymptomatic in their early stages . These insights underscore the need for more accessible, non-invasive, and proactive screening methods that do not rely on symptomatic awareness or frequent visits to healthcare facilities. Many assent to the use of sanitary pads with test strips as a means of regular testing (see Figure 4).

Our project seeks to address these issues by integrating an easy-to-use, point-of-care diagnostic tool directly into everyday life, enabling women to monitor their health regularly without the constant need for invasive procedures or costly lab tests.

Figure 1: the examination frequency for rural residents in China based on the public survey sent out

Figure 2: the physical examination frequency of all six hundred sixty valid responses from female across different age groups and residential locations

Figure 3: the key determinants affecting the physical examination rates of the six hundred sixty female participants across different age groups and residential locations

Figure 4: the acceptance/aspiration among participants for using innovative sanitary pads with test strips to regularly monitor health conditions

The Problem

In a nutshell, the lack of distinct symptoms and the lack of awareness prevent the women around us as well as women globally from getting potentially lifesaving screenings for gynecological diseases. There lacks a messenger that would notify them when a screening is necessary, so women can be aware of their own health. Something that would be simple and quick, that would not become a burden to use in everyday life.

The Solution

Combining all the necessary requirements for our solution, we decided to create the Luna Pad. The Luna Pad would serve as a menstrual health monitoring solution designed to provide women with an easy and effective way to monitor their health during menstruation, using menstrual blood. The form of a menstrual pad was chosen because they are the most widely used feminine hygiene product globally, utilized by 46-89% of women in various countries [13] . The Luna Pad integrates a test strip into a standard pad, offering a way to gain health insights during menstruation. The test strip would communicate to the user when a certain biomarker is of high abundance, which would signal high likelihood of a certain gynecological disease.

The Luna Pad's testing mechanism is built around three main components:

1. Antibody-antigen binding: Many gynecological diseases produce symbolic protein biomarkers. To detect the presence of these proteins, we plan to synthesize antibodies that can bind to them using genetically modified bacteria.

2. scFv: Producing full-length antibodies is challenging, and we decided to design single-chain variable fragment (scFv) antibodies. These scFv antibodies are minimal antigen-binding fragments that can be better expressed and folded correctly in eukaryotic organisms like E. coli. due to their simplified architecture. If applied, producing a mere fragment of the antibody can also lower the cost during mass production. Refer to our Engineering page for more details of the synthetic biology design.

3. Test Strip: The test strip works similar to COVID-19 antigen test; it uses the lateral flow immunoassay mechanism where a line with specific scFv antibodies will be lined up and if the biomarker is detected in high abundance, the test strip would reflect this visually providing the user with a straightforward and immediate result.

Diving Deeper into Our Solution

>Biomarkers

Through literature review and doctor interviews, we learned about many disease biomarkers as our target candidates. These include:

1. CA125 (Cancer Antigen 125): CA125 is a tumor marker primarily used in the management of ovarian cancer. It is often used to monitor the treatment response and to detect the recurrence of the disease. However, elevated levels can also be found in other non-ovarian cancers.

2. CA199 (Carbohydrate Antigen 19-9): CA199 is a tumor marker that is often elevated in pancreatic cancer but can also be increased in other malignancies and some non-malignant conditions. It is used as a diagnostic, prognostic, and therapeutic indicator in pancreatic cancer.

3. HE4 (Human Epididymis Protein 4): HE4 is a blood test that is used, along with CA125, for the diagnosis and monitoring of ovarian cancer. It is a relatively new biomarker and has been found to be useful in differentiating ovarian cancer from other benign conditions.

4. SCC (Squamous Cell Carcinoma Antigen): SCC is a tumor marker used for the detection and monitoring of various types of squamous cell carcinomas, including those of the cervix, lungs, and head and neck. It is particularly useful in monitoring the response to treatment and detecting recurrence .

5. CEA (Carcinoembryonic Antigen): CEA is a protein that is often elevated in several types of cancer, including colorectal, breast, ovarian, and lung cancer. It is used to monitor treatment effectiveness and detect cancer recurrence. However, it is not specific to any particular type of cancer and can also be elevated in non-malignant conditions.

6. AFP (Alpha-fetoprotein): AFP is a protein normally produced by a developing fetus. Elevated levels of AFP can be found in patients with liver cancer, germ cell tumors of the testicles or ovaries, and some other types of cancer. It is used for diagnosis, monitoring treatment, and detecting recurrence.

7. β-hCG (Beta-human Chorionic Gonadotropin): Produced by cells during pregnancy, β-hCG can also be produced by some germ cell tumors and other types of cancer. It is used to monitor the effectiveness of treatment for these cancers and detect their recurrence.

8. CA72-4: CA72-4 is a tumor marker that is used in the diagnosis and monitoring of gastric cancer. It may also be elevated in other malignancies and non-malignant conditions. When used in combination with other tumor markers, it can improve the accuracy of cancer detection.

9. NSE (Neuron-Specific Enolase): NSE is an enzyme that can be elevated in patients with small cell lung cancer and neuroendocrine tumors. It is used to monitor the response to treatment and to detect the recurrence of these types of cancer.

10. ER (Estrogen Receptor) and PR (Progesterone Receptor): ER and PR are proteins that are found in certain types of breast cancer. They are used to determine the most appropriate treatment for breast cancer patients and to predict the likelihood of the cancer responding to hormone therapy.

11. HPV-DNA: Human Papillomavirus (HPV) DNA testing is a method used to detect the presence of high-risk HPV types that are associated with cervical cancer. It is used as a primary screening tool for cervical cancer in many countries.

Meanwhile, we also learned about many common pro-inflammatory biomarkers in biomedical studies that often co-exist with both cancerous and non-cancerous conditions.

1. Interleukin-6 (IL-6): IL-6 is a cytokine that plays a key role in the immune response and the acute phase reaction. It is produced by various cells, including T cells, B cells, and macrophages. Elevated levels of IL-6 have been associated with various inflammatory diseases, autoimmune diseases, and cancers.

2. Interleukin-10 (IL-10): IL-10 is an anti-inflammatory cytokine produced by various cell types, including monocytes and macrophages. It helps to regulate the immune response by inhibiting the production of pro-inflammatory cytokines. It has been implicated in the suppression of immune responses during infections and in the development of immune tolerance.

3.Tumor Necrosis Factor (TNF): The TNF family of cytokines, which includes TNF-α and TNF-β, are involved in systemic inflammation and are important in the regulation of immune cells. In particular, TNF-α is a key mediator in the inflammatory response and is produced by macrophages in response to infection or injury. It has been associated with a variety of autoimmune diseases and is a target for biologic therapies.

4. Interferons (IFNs): IFNs are a group of signaling proteins made and released by host cells in response to the presence of pathogens such as viruses, bacteria, parasites, or tumor cells. There are several types of IFNs, including IFN-α, IFN-β, and IFN-γ. IFN-γ, for example, is produced by natural killer cells and T cells and plays a critical role in immune responses against pathogens and tumors.

>Hardware

To provide a visual read-out upon disease biomarker detection, the pad is designed to include a discreet "window strip" on the reverse side, similar to a COVID-19 rapid test kit, providing easily interpretable results. We considered the type of menstrual pad, the positioning of the test strip, and the flow of fluid sample to study realistic conditions.

The test strip needs to collect sufficient sample menstrual fluid, and we considered building relevant hardwares using 3D-printed models and silicone models to study sample collection.

Despite these engineered components, LUNA pad must maintain a slim profile to ensure user comfort. While current prototypes are priced at a few dozen Chinese Yuan, potential mass production and collaboration with established pad manufacturers could substantially reduce costs. LUNA offers a non-invasive and accessible method for women to monitor their gynecological health during regular menstrual cycles.

Biblography

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