Updated Cushing’s disease guideline highlights new diagnosis, treatment ‘roadmap’

Posted on November 15, 2021 by MaryO

An updated guideline for the treatment of Cushing’s disease focuses on new therapeutic options and an algorithm for screening and diagnosis, along with best practices for managing disease recurrence.

Despite the recent approval of novel therapies, management of Cushing’s disease remains challenging. The disorder is associated with significant comorbidities and has high mortality if left uncontrolled.

Adrenal transparent _Adobe
Source: Adobe Stock

“As the disease is inexorable and chronic, patients often experience recurrence after surgery or are not responsive to medications,” Shlomo Melmed, MB, ChB, MACP, dean, executive vice president and professor of medicine at Cedars-Sinai Medical Center in Los Angeles, and an Endocrine Today Editorial Board Member, told Healio. “These guidelines enable navigation of optimal therapeutic options now available for physicians and patients. Especially helpful are the evidence-based patient flow charts [that] guide the physician along a complex management path, which usually entails years or decades of follow-up.”

Shlomo Melmed

The Pituitary Society convened a consensus workshop with more than 50 academic researchers and clinical experts across five continents to discuss the application of recent evidence to clinical practice. In advance of the virtual meeting, participants reviewed data from January 2015 to April 2021 on screening and diagnosis; surgery, medical and radiation therapy; and disease-related and treatment-related complications of Cushing’s disease, all summarized in recorded lectures. The guideline includes recommendations regarding use of laboratory tests, imaging and treatment options, along with algorithms for diagnosis of Cushing’s syndrome and management of Cushing’s disease.

Updates in laboratory, testing guidance

If Cushing’s syndrome is suspected, any of the available diagnostic tests could be useful, according to the guideline. The authors recommend starting with urinary free cortisol, late-night salivary cortisol, overnight 1 mg dexamethasone suppression, or a combination, depending on local availability.

If an adrenal tumor is suspected, the guideline recommends overnight dexamethasone suppression and using late-night salivary cortisol only if cortisone concentrations can also be reported.

The guideline includes several new recommendations in the diagnosis arena, particularly on the role of salivary cortisol assays, according to Maria Fleseriu, MD, FACE, a Healio | Endocrine Today Co-editor, professor of medicine and neurological surgery and director of the Pituitary Center at Oregon Health & Science University in Portland.

Maria Fleseriu

“Salivary cortisol assays are not available in all countries, thus other screening tests can also be used,” Fleseriu told Healio. “We also highlighted the sequence of testing for recurrence, as many patients’ urinary free cortisol becomes abnormal later in the course, sometimes up to 1 year later.”

The guideline states combined biochemical and imaging for select patients could potentially replace petrosal sinus sampling, a very specialized procedure that cannot be performed in all hospitals, but more data are needed.

“With the corticotropin-releasing hormone stimulation test becoming unavailable in the U.S. and other countries, the focus is now on desmopressin to replace corticotropin-releasing hormone in some of the dynamic testing, both for diagnosis of pseudo-Cushing’s as well as localization of adrenocorticotropic hormone excess,” Fleseriu said.

The guideline also has a new recommendation for anticoagulation for high-risk patients; however, the exact duration and which patients are at higher risk remains unknown.

“We always have to balance risk for clotting with risk for bleeding postop,” Fleseriu said. “Similarly, recommended workups for bone disease and growth hormone deficiency have been further structured based on pitfalls specifically related to hypercortisolemia influencing these complications, as well as improvement after Cushing’s remission in some patients, but not all.”

New treatment options

The guideline authors recommended individualizing medical therapy for all patients with Cushing’s disease based on the clinical scenario, including severity of hypercortisolism. “Regulatory approvals, treatment availability and drug costs vary between countries and often influence treatment selection,” the authors wrote. “However, where possible, it is important to consider balancing cost of treatment with the cost and the adverse consequences of ineffective or insufficient treatment. In patients with severe disease, the primary goal is to treat aggressively to normalize cortisol concentrations.”

Fleseriu said the authors reviewed outcomes data as well as pros and cons of surgery, repeat surgery, medical treatments, radiation and bilateral adrenalectomy, highlighting the importance of individualized treatment in Cushing’s disease.

“As shown over the last few years, recurrence rates are much higher than previously thought and patients need to be followed lifelong,” Fleseriu said. “The role of adjuvant therapy after either failed pituitary surgery or recurrence is becoming more important, but preoperative or even primary medical treatment has been also used more, too, especially in the COVID-19 era.”

The guideline summarized data on all medical treatments available, either approved by regulatory agencies or used off-label, as well as drugs studied in phase 3 clinical trials.

“Based on great discussions at the meeting and subsequent emails to reach consensus, we highlighted and graded recommendations on several practical points,” Fleseriu said. “These include which factors are helpful in selection of a medical therapy, which factors are used in selecting an adrenal steroidogenesis inhibitor, how is tumor growth monitored when using an adrenal steroidogenesis inhibitor or glucocorticoid receptor blocker, and how treatment response is monitored for each therapy. We also outline which factors are considered in deciding whether to use combination therapy or to switch to another therapy and which agents are used for optimal combination therapy.”

Future research needed

The guideline authors noted more research is needed regarding screening and diagnosis of Cushing’s syndrome; researchers must optimize pituitary MRI and PET imaging using improved data acquisition and processing to improve microadenoma detection. New diagnostic algorithms are also needed for the differential diagnosis using invasive vs. noninvasive strategies. Additionally, the researchers said the use of anticoagulant prophylaxis and therapy in different populations and settings must be further studied, as well as determining the clinical benefit of restoring the circadian rhythm, potentially with a higher nighttime medication dose, as well as identifying better markers of disease activity and control.

“Hopefully, our patients will now experience a higher quality of life and fewer comorbidities if their endocrinologist and care teams are equipped with this informative roadmap for integrated management, employing a consolidation of surgery, radiation and medical treatments,” Melmed told Healio.

From https://www.healio.com/news/endocrinology/20211029/updated-cushings-disease-guideline-highlights-new-diagnosis-treatment-roadmap

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Sparrow Pharmaceuticals Hopes To Change The Future Of Endocrinology

Posted on November 5, 2021 by MaryO

By Ed Miseta, Chief Editor, Clinical Leader
Follow Me On Twitter @EdClinical

Go ahead and continuously improvement iStock-1295289697

Sparrow Pharmaceuticals is an emerging biopharma company on a mission to help patients suffering from an excess of corticosteroids, with a focus on Cushing’s syndrome, autonomous cortisol secretion (ACS), and polymyalgia rheumatica (PMR).

Cushing’s and ACS are both caused by an excess of cortisol produced by tumors. Patients with Cushing’s can present physically with a fatty hump between their shoulders, a rounded face, and pink or purple stretch marks on their skin. Cushing’s syndrome and ACS can both result in high blood pressure, bone loss, type 2 diabetes, weight gain, and mood, cognition, and sleep disorders. Any of those symptoms may be side effects for patients with conditions such as PMR who rely on long-term treatment with corticosteroid medications such as prednisone.

“Cushing’s syndrome impacts around 20,000 patients in the U.S. alone,” says David Katz, Chief Scientific Officer for Sparrow. “Approximately 50% of those patients can be cured by surgery, but some will develop another tumor years later. ACS is an under-recognized condition, but it may affect up to 3 million patients in the U.S. There are also around 2 million people in the U.S. who rely on long-term use of corticosteroid medications to control autoimmune diseases and other conditions.”

The treatments being developed by Sparrow are based on recognition that cortisol and corticosteroid medications are activated in certain tissues such as the liver, bone, fat, and brain, where in excess they act to cause toxicity. The company’s investigational drugs inhibit HSD-1, the enzyme responsible for that activation.

Sparrow is about to launch a Phase 2 trial for Cushing’s syndrome. In early 2022 the company will also begin two additional Phase 2 trials for ACS and PMR, a common autoimmune disease in elderly patients. PMR is an arthritic syndrome characterized by a phenomenon known as claudication, which means the more you use a limb, the more it hurts and the harder it is to use. “For example, the more a PMR patient walks, the more painful and stiff their legs will become,” says Katz. “If they’re trying to do anything with their arms, the arms will get stiffer and more painful. The disease is pretty debilitating in terms of physical function. The only approved treatment for PMR is steroids, which have side effects such as diabetes, hypertension, osteoporosis, and fractures.”

Unknown Clinical Challenges

Katz is excited about the clinical trials for ACS and PMR because no sizable interventional trials have been reported in either of those conditions.

“We’re going into a completely new area, and we don’t know what we’re going to encounter in terms of patient recruitment and retention,” says Katz. “There is also no strong precedent for how to get approval for a drug in these conditions. The only treatment indicated for PMR is steroids, and that came without any efficacy clinical trials. There are no drugs approved for ACS. It’s hard to anticipate the challenges we will face when we are in an area that is very new.”

Patient centricity is a topic that is very important to Katz, and he spends a lot of time thinking about how to make trials a more pleasant experience for patients by limiting the burden placed on them. He notes that can sometimes be a difficult trade-off because of the procedures that must be performed to meet regulatory standards.

“In Cushing’s syndrome clinical care and clinical trials, the standard way for someone’s cortisol level to be measured is a 24-hour urine collection,” states Katz. “That involves looking at the amount of cortisol in the urine over a 24-hour period. That collection is inconvenient and burdensome, and the patient must then carry it somewhere to be analyzed.”

Sparrow hopes to shift that collection to a spot urine sample, like what patients would experience during a physical. The patient would urinate into a cup and hand it off to a clinic employee for analysis. The process would be much simpler and less burdensome for the patient. Sparrow will first need to prove that in a clinical trial the spot sample will work as well or better than the 24-hour collection. Subjects in the initial clinical trials will have to contribute the 24-hour collections so that Sparrow can demonstrate that future patients will not need to do so.

The Future of Endocrinology

Katz has a positive outlook on the future of endocrinology. Sparrow’s leading drug candidate, SPI-62, is an oral, small-molecule HSD-1 inhibitor. In four clinical trials, it demonstrated potent targeting of HSD-1 in both the brain and liver, and significantly lowered cortisol levels in the liver. The studies also showed a favorable safety and tolerability profile.

“If we are successful at developing SPI-62, I believe it will change the field of endocrinology,” says Katz. “We aim to shift the focus in Cushing’s syndrome to intracellular cortisol as the main driver of symptoms. What I mean by that is if we find that SPI-62 substantially reduces symptoms and that the degree of inhibition of our target HSD-1 correlates well with clinical improvement, then we can get to a new standard of care. We can potentially get rid of the 24-hour urine collections, which will be a big relief to patients. Additionally, many of today’s drugs have a side effect called adrenal insufficiency, which results when the drugs either reduce cortisol too much or completely block activity. Many of today’s drugs also require frequent monitoring and dose titration to prevent adrenal insufficiency. We believe that with HSD-1 inhibition we might avoid adrenal insufficiency as well.”

Katz is hopeful patients treated with SPI-62 will not require monitoring and dose titration. That proof will take years and lots of clinical trials. Sparrow may also produce the first targeted therapy for ACS. That could improve the recognition of ACS as a prevalent form of hypercortisolism and a substantial cause of morbidity and mortality.

“ACS is probably the most under-recognized condition in endocrinology based on recent epidemiological studies,” adds Katz. “It’s possible that as few as 3% of patients who have ACS actually have a diagnosis.  That is shocking for a condition that is associated with a lot of cardiometabolic and bone morbidity, negative effects on mood and cognition, sleep, and muscle strength, and is associated with excess mortality. We want to bring attention to this condition by bringing out a targeted therapy to treat a spectrum of symptoms by getting to the root cause of them.”

From https://www.clinicalleader.com/doc/sparrow-pharmaceuticals-hopes-to-change-the-future-of-endocrinology-0001

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Diagnostic pitfalls in Cushing’s disease impacting surgical remission rates; test thresholds and lessons learned in 105 patients

Posted on September 7, 2021 by MaryO

This article was originally published here

J Clin Endocrinol Metab. 2021 Sep 3:dgab659. doi: 10.1210/clinem/dgab659. Online ahead of print.

ABSTRACT

CONTEXT: Confirming a diagnosis of Cushing’s disease (CD) remains challenging yet is critically important before recommending transsphenoidal surgery for adenoma resection.

OBJECTIVE: To describe predictive performance of preoperative biochemical and imaging data relative to post-operative remission and clinical characteristics in patients with presumed CD.

DESIGN, SETTING, PATIENTS, INTERVENTIONS: Patients (n=105; 86% female) who underwent surgery from 2007-2020 were classified into 3 groups: Group A (n=84) pathology-proven ACTH adenoma; Group B (n=6) pathology-unproven but with postoperative hypocortisolemia consistent with CD, and Group C (n=15) pathology-unproven, without postoperative hypocortisolemia. Group A+B were combined as Confirmed CD and Group C as Unconfirmed CD.

MAIN OUTCOMES: Group A+B was compared to Group C regarding predictive performance of preoperative 24-hour urinary free cortisol (UFC), late night salivary cortisol (LNSC), 1mg dexamethasone suppression test (DST), plasma ACTH, and pituitary MRI.

RESULTS: All groups had a similar clinical phenotype. Compared to Group C, Group A+B had higher mean UFC (p<0.001), LNSC(p=0.003), DST(p=0.06), ACTH(p=0.03) and larger MRI-defined lesions (p<0.001). The highest accuracy thresholds were: UFC 72 µg/24hrs; LNSC 0.122 µg/dl, DST 2.70 µg/dl, and ACTH 39.1 pg/ml. Early (3-month) biochemical remission was achieved in 76/105 (72%) patients: 76/90(84%) and 0/15(0%) of Group A+B versus Group C, respectively, p<0.0001. In Group A+B non-remission was strongly associated with adenoma cavernous sinus invasion.

CONCLUSIONS: Use of strict biochemical thresholds may help avoid offering transsphenoidal surgery to presumed CD patients with equivocal data and improve surgical remission rates. Patients with Cushingoid phenotype but equivocal biochemical data warrant additional rigorous testing.

PMID:34478542 | DOI:10.1210/clinem/dgab659

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Home cortisol tests: 3 of the best

Posted on May 1, 2021 by MaryO

Please note that if you buy through links in this article, Medical News Today may earn a small commission. Here’s their process.

Cortisol is a hormone with various functions throughout the body. However, if a person’s body cannot regulate their cortisol levels, it could lead to a serious health condition. In these cases, home cortisol tests may be useful to indicate when someone might need medical attention.

A person sitting at a desk, holding an at-home cortisol test tube, typing on a laptop.

This article discusses:

  • what cortisol is
  • what a home cortisol test is
  • why a person might buy a home cortisol test
  • some home cortisol tests to purchase online
  • when to see a doctor

What is cortisol?

Cortisol is the stress hormone that affects several systems in the body, including the:

The adrenal glands produce cortisol. Most human body cells have cortisol receptors, and the hormone can help in several ways, including:

  • reducing inflammation
  • regulating metabolism
  • assisting with memory formation
  • controlling blood pressure
  • developing the fetus during pregnancy
  • maintaining salt and water balance in the body
  • controlling blood sugar levels

All these functions make cortisol a vital part of maintaining overall health. If the body can no longer regulate cortisol levels, it can lead to several health disorders, such as Cushing’s syndrome and Addison’s disease. Without treatment, these conditions could cause life threatening complications.

The body requires certain cortisol levels during times of stress, such as:

  • in the event of an injury
  • during illness
  • during a surgical procedure

What are home cortisol tests? 

A cortisol test usually involves a blood test. However, some may require saliva and urine samples instead.

There are several home cortisol tests available to purchase over the counter or online. These allow a person to take a sample of blood, urine, or saliva before sending it off for analysis.

After taking a home cortisol test, people can usually receive their results within 2–5 days online or via a telephone call with a healthcare professional.

However, there are currently no studies investigating the reliability of these home cortisol tests. Therefore, people should follow up on their test results with a healthcare professional.

Why and when do people need them? 

A person should take a home cortisol test if they feel they may have a cortisol imbalance.

If cortisol levels are too high, a person may notice the following:

  • rapid weight gain in the face, chest, and abdomen
  • high blood pressure
  • osteoporosis
  • bruises and purple stretch marks
  • mood swings
  • muscle weakness
  • an increase in thirst and need to urinate

If cortisol levels are too low, a person may experience the following symptoms:

  • fatigue
  • loss of appetite
  • unintentional weight loss
  • muscle weakness
  • abdominal pain

Additionally, low cortisol levels may lead to:

A test can help individuals check their cortisol levels. If the test results show these levels are too high or too low, people should seek medical advice.

A cortisol imbalance may be a sign of an underlying condition, which can lead to serious complications without treatment.

If a person cannot carry out a home cortisol test, they should speak to a medical professional who can arrange a cortisol test at a healthcare facility.

What to look for in a home cortisol test

At a clinic or hospital setting, a medical professional will usually take a blood sample and analyze it for an individual’s cortisol levels.

Home cortisol tests involve a person taking a sample of blood, urine, or saliva. There are currently no studies investigating the accuracy of these results.

However, home cortisol tests may be faster and more convenient than making an appointment with a doctor to take a sample.

People may consider several factors when deciding to purchase a home cortisol test, including:

  • Sample type: Some tests require a blood sample, while others need a sample of urine or saliva. With this in mind, a person may wish to buy a product that uses a testing method they are comfortable providing.
  • Test analysis: A person may wish to purchase a product from a company that sends tests to Clinical Laboratory Improvement Amendments (CLIA)-certified labs for analysis. The Food and Drug Administration (FDA), Center for Medicaid Services, and the Centers for Disease Control and Prevention (CDC) regulate these labs to help ensure safety and accuracy.
  • Accuracy: Individuals may wish to speak to a pharmacist or other healthcare professional before purchasing to ensure the test is reliable and accurate.

Products

Several online retailers offer home cortisol tests. It is important to follow all test instructions to ensure a valid result.

Please note, the writer has not tested these products. All information is research-based.

LetsGetChecked – Cortisol Test

This cortisol test uses the finger prick method to draw blood for the sample.

Here are the steps to take and send off a blood sample:

  1. Individuals fill in their details on the collection box and activate their testing kit online at the LetsGetChecked website.
  2. People need to wash their hands with warm soapy water before using an alcohol swab to clean the finger that they will prick.
  3. Once the finger is completely dry, individuals pierce the skin using the lancet in the test kit. A person must wipe away the first drop of blood before squeezing some into the blood collection tube.
  4. After closing the tube, individuals must invert it 5–10 times before placing it in the included biohazard bag, which they then place in the box.

After following these steps, people can send the sample back to LetsGetChecked using the kit’s prepaid envelope. Test results usually come back within 2–5 days.

LetsGetChecked tests samples in the same labs that primary care providers, hospitals, and government schemes use. These labs are CLIA-certified and CAP-accredited.

The company also has a team of nurses and doctors available 24 hours a day, 7 days a week, to offer ongoing support. These healthcare professionals are on hand to discuss a person’s results with them over the phone.

Everlywell At-Home Cortisol Levels Test Kit – Sleep & Stress Test

This Everlywell product uses a urine sample to test a person’s cortisol levels.

The test measures the levels of three hormones in a person’s body: cortisol, cortisone, and melatonin. It also measures a person’s creatinine levels.

There are three steps with this test:

  1. Individuals register their testing kit on Everlywell’s website.
  2. A person follows the instructions carefully to take their urine sample.
  3. Once they have their urine sample, they place it in the prepaid package and send it off to Everlywell’s labs.

Within a few days, individuals will receive their results digitally via the Everlywell website. Medical professionals can also offer helpful insights via their secure platform.

As well as sending a personalized report of each marker, Everlywell also sends detailed information about what the results mean.

The labs where Everlywell tests samples all carry certification with CLIA. The company also ensures that all results are reviewed and certified by independent board-certified physicians within the person’s specific state.SHOP NOW

Healthlabs Cortisol, AM & PM Test

Healthlabs offers a cortisol test that tests a person’s cortisol levels twice — once in the morning and once in the evening.

The company says they do this because a person’s cortisol levels fluctuate throughout the day. Therefore, by testing twice, they can gather information on this fluctuation.

This test uses a blood sample, which a person takes once in the morning and once in the afternoon. They must follow the instructions clearly to ensure they take suitable samples.

The manufacturer says that people should collect a morning sample between 7–9 a.m. and an evening sample between 3–5 p.m.

They then need to send off their sample for analysis. After testing is complete at a CLIA-certified lab, a person will receive their results, which usually takes between 1–2 days. SHOP NOW

When to speak with a doctor

A person should undergo a cortisol test if they believe they may have high or low cortisol levels.

They can do this at home or speak with a medical professional who can carry out the test for them.

People may also wish to seek medical help if they show signs of too much or too little cortisol. This could indicate a potentially serious underlying health issue.

Summary

Cortisol is an important hormone that affects almost all parts of the body. It has many functions, including reducing inflammation, regulating metabolism, and controlling blood pressure.

If a person believes they have high or low cortisol levels, they may wish to take a cortisol test. Usually, these tests take place at a medical practice. However, several home cortisol tests are available to purchase.

A person can take these tests at home by providing a urine, blood, or saliva sample. Once a lab analyzes the test, people usually receive their results within a few days. Individuals should follow up any test results with a healthcare professional. No clinics, no stress. Test your cortisol levels from home

Test your cortisol level from home with LetsGetChecked. Get free shipping, medical support, and results from accredited labs within 2–5 days. Order today for 30% off. LEARN MORE

Last medically reviewed on April 29, 2021 at https://www.medicalnewstoday.com/articles/3-of-the-best-home-cortisol-tests

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Smart, Soft Contact Lens For Wireless Immunosensing of Cortisol

Posted on July 18, 2020 by MaryO

Abstract

Despite various approaches to immunoassay and chromatography for monitoring cortisol concentrations, conventional methods require bulky external equipment, which limits their use as mobile health care systems. Here, we describe a human pilot trial of a soft, smart contact lens for real-time detection of the cortisol concentration in tears using a smartphone. A cortisol sensor formed using a graphene field-effect transistor can measure cortisol concentration with a detection limit of 10 pg/ml, which is low enough to detect the cortisol concentration in human tears. In addition, this soft contact lens only requires the integration of this cortisol sensor with transparent antennas and wireless communication circuits to make a smartphone the only device needed to operate the lens remotely without obstructing the wearer’s view. Furthermore, in vivo tests using live rabbits and the human pilot experiment confirmed the good biocompatibility and reliability of this lens as a noninvasive, mobile health care solution.

INTRODUCTION

The steroid hormone, cortisol, which is known as a stress hormone, is secreted by the adrenal gland when people are stressed psychologically or physically (1). This secretion occurs when the adrenal gland is stimulated by adrenocorticotropic hormone, which is secreted by the pituitary gland when it is stimulated by the corticotropin-releasing hormone secreted by the hypothalamus. This serial cortisol secretion system is referred to as a hypothalamus–pituitary gland–adrenal gland axis, which is affected by chronic stress, resulting in abnormal secretion of cortisol (2, 3). The accumulation of cortisol caused by the abnormal secretion of cortisol increases the concentrations of fat and amino acid, which can result in diverse severe diseases (e.g., Cushing’s disease, autoimmune disease, cardiovascular complications, and type 2 diabetes) and neurological disorders (such as depression and anxiety disorders) (2–7). In contrast, abnormally low cortisol levels can lead to Addison’s disease, which results in hypercholesterolemia, weight loss, and chronic fatigue (8). In addition, it was recently reported that plasma cortisol can be correlated to the prognosis of traumatic brain injury (9). Furthermore, the extent of cortisol secretion varies from person to person, and it changes continuously (10, 11). Thus, developing health care systems for real-time monitoring of the cortisol level has been explored extensively over the past decade as the key to the quantitative analysis of stress levels. Although various efforts have led to the development of cortisol sensors that can measure the concentration of cortisol in blood, saliva, sweat, hair, urine, and interstitial fluid (12–17), the accurate measurement of cortisol concentrations has been limited because of the difficulties associated with the transportation and storage of cortisol as well as the instability of the biologically active cortisol in these body fluids at room temperature. In addition, these conventional sensing methods require bulky equipment for the extraction and analysis of these body fluids, which is not suitable for mobile health care systems (12, 18). Therefore, the development of noninvasive and wearable sensors that can monitor cortisol concentration accurately is highly desirable for a smart health care solution. For example, the immunoassay method, which uses an antigen-antibody binding reaction, has been used extensively for electrochemical cortisol immunosensors using saliva and interstitial fluid, except tears (12, 14, 19). However, these immunosensors still require the use of bulky impedance analyzers for the analysis of the Nyquist plot from electrochemical impedance spectroscopy. Although the cyclic voltammetry (CV) technique can be used as an alternative approach for sensing cortisol, additional bulky electrochemical instruments still are necessary for analyzing the CV curves (13, 14, 19). Recently, wearable forms of cortisol sensors that use sweat were developed (15), but they still required bulky measurement equipment (15, 16). Therefore, portable and smart sensors that can monitor the accurate concentration of cortisol in real time are highly desirable for use in mobile health care.

Among the various body fluids, tears, in particular, contain important biomarkers, including cortisol (20, 21). Thus, the integration of biosensors with contact lenses is a potentially attractive candidate for the noninvasive and real-time monitoring of these biomarkers from tears (22–25). However, an approach for fabricating a smart contact lens for sensing the cortisol in tears has not been demonstrated previously. Thus, here, we present an extraordinary approach for the formation of a smart, soft contact lens that enables remote, real-time monitoring of the cortisol level in the wearer’s tears using mobile phones. This smart, soft contact lens is composed of a cortisol sensor, a wireless antenna, capacitors, resistors, and integrated circuit chips that use stretchable interconnects without obstructing the wearer’s view. The components of this device (except the antenna) were protected from mechanical deformations by locating each of the components on discrete, rigid islands and by embedding these islands inside an elastic layer. A graphene field-effect transistor (FET; with the binding of monoclonal antibody) was used as this cortisol immunosensor, which exhibited a sufficiently low detection limit, i.e., 10 pg/ml, for its sensing of cortisol in human tears in which the cortisol concentration ranges from 1 to 40 ng/ml (26). This sensor was integrated with a near-field communication (NFC) chip and antenna inside the soft contact lens for the real-time wireless transmission of the data to the user’s mobile device (e.g., a smart phone or a smart watch). The antenna occupies a relatively large area of this soft lens, so it requires its high stretchability, good transparency, and low resistance for operating a standard NFC chip at 13.56 MHz. In our approach, the hybrid random networks of ultralong silver nanofibers (AgNFs) and fine silver nanowires (AgNWs) enabled high transparency and good stretchability of this antenna and its low sheet resistance for reliable standard NFCs (at 13.56 MHz) inside this smart contact lens. Thus, the fully integrated system of this smart contact lens provided wireless and battery-free operation for the simultaneous detection and transmission of the cortisol concentration from tears to a mobile phone using standard NFC. In addition, a human pilot trial and in vivo tests conducted using live rabbits demonstrated the biocompatibility of this lens, and its safety against inflammation and thermal/electromagnetic field radiation suggests its substantial usability as a noninvasive, mobile health care solution.

RESULTS

Cortisol immunosensor

A graphene FET sensor was fabricated by binding the cortisol monoclonal antibody (C-Mab) to the surface of graphene for the immunosensing of cortisol. Here, graphene acts as a transducer that converts the interaction between cortisol and C-Mab into electrical signals. Figure 1A shows the immobilization process of C-Mab to graphene. Immobilization proceeds through amide bonding of the C-Mab onto the carboxyl group of the graphene surface via the EDC [1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride]/NHS (N-hydroxysulfosuccinimide) coupling reaction. A chemical vapor deposition–synthesized graphene layer was transferred onto a desired substrate and exposed to ultraviolet ozone (UVO) to activate the surface of the graphene with the carboxylate group. Figure S1 shows the contact angle between this surface of the graphene and a droplet of deionized (DI) water. Longer exposure time to UVO can decrease the hydrophobicity of graphene with decreasing the contact angle. Table S1 shows the increase in the electrical resistance of graphene that resulted from this UVO treatment. In our experiment, 2 min of exposure time to UVO decreased the contact angle from 70° to 38° without increasing the resistance of the graphene notably. UVO exposure times longer than this threshold time degraded the resistance of the graphene excessively, so the time of exposure of our samples to UVO was limited to 2 min. Figure S2A illustrates the process of immobilizing C-Mab through the EDC/NHS coupling reaction. This two-step coupling reaction of EDC and NHS can mediate the amide bonding between the carboxylate group of the UVO-exposed graphene and the amine group of the protein (12, 17, 27, 28). Here, EDC forms reactive O-acylisourea ester, thereby making the surface unstable. This O-acylisourea ester reacts with the NHS to form amine-reactive NHS ester with the surface still remaining semistable. Then, C-Mab with the amine group reacts with the amine-reactive NHS ester, thereby forming stable amide bonding that can immobilize C-Mab to the NHS on the surface of the graphene. Figure S2B shows the Fourier transform infrared (FTIR) spectroscopy spectra of the DI water after the cortisol sensor had been immersed for 24 hours. The spectra of the DI water in which the sensor was immersed were not significantly different from those of the pristine DI water. However, the C-Mab solution that had a concentration of 1 μg/ml had a significant peak intensity in the range of 3000 to 2800 cm−1, representing the N-H bonding in the C-Mab. These results indicated that C-Mab formed stable bonding on the carboxylated graphene and was negligibly detached by exposure to water.

From https://advances.sciencemag.org/content/6/28/eabb2891

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