Biosensor and Lab-on-a-chip Biomarker-identifying Technologies for Oral and Periodontal Diseases

Abstract

Periodontitis is a complex multifactorial disease that can lead to destruction of tooth supporting tissues and subsequent tooth loss. The most recent global burden of disease studies highlight that severe periodontitis is one of the most prevalent chronic inflammatory conditions affecting humans. Periodontitis risk is attributed to genetics, host-microbiome and environmental factors. Empirical diagnostic and prognostic systems have yet to be validated in the field of periodontics. Early diagnosis and intervention prevents periodontitis progression in most patients. Increased susceptibility and suboptimal control of modifiable risk factors can result in poor response to therapy, and relapse. The chronic immune-inflammatory response to microbial biofilms at the tooth or dental implant surface is associated with systemic conditions such as cardiovascular disease, diabetes or gastrointestinal diseases. Oral fluid-based biomarkers have demonstrated easy accessibility and potential as diagnostics for oral and systemic diseases, including the identification of SARS-CoV-2 in saliva. Advances in biotechnology have led to innovations in lab-on-a-chip and biosensors to interface with oral-based biomarker assessment. This review highlights new developments in oral biomarker discovery and their validation for clinical application to advance precision oral medicine through improved diagnosis, prognosis and patient stratification. Their potential to improve clinical outcomes of periodontitis and associated chronic conditions will benefit the dental and overall public health.

Keywords: biomarkers; biotechnology; patient stratification; periodontal diseases/periodontitis; precision medicine; saliva.

FIGURE 1

The systems approach to advance precision oral medicine. Schematic diagram illustrating integration of modifiable and nonmodifiable risk factors, and immune-metabolic signatures for biomarker identification, patient stratification, and understanding of molecular mechanisms for oral diseases. The oral soft and hard tissue phenotype is determined by genetic, environmental, and microbial factors. The phenotype is reflected by tissue integrity and immune functions that control the pathogenicity of the oral biofilms. Integrative analysis of data sets (e.g., genomics, proteomics, lipidomics) are used to dissect the changes in tissue structure and immune functions in different subjects and thereby identify biomarkers associated with specific phenotypes. Subject segmentation is necessary for improved clinical trial design and precise treatment approaches. It can also serve as a basis for analysis of dynamic responses to treatment strategies and the identification of molecular mechanisms underlying different phenotypes. Bioinformatic analyses using AI on comprehensive ‘omics data sets to interpret network dynamics across omics layers help develop precise and personalized treatment schemes for oral and associated systemic conditions.

FIGURE 2

Patient stratification workflow for oral screening and monitoring. Multi-level omics analyses (Trans-OWAS) analyses are used to construct the relationships between periodontal phenotypes, which collectively define the phenome, and key biomarkers identified across omics layers. The combination of genetic (1) and environmental information (2) to develop deep learning algorithms from dense population-wide data helps us design periodontal phenotype-specific biomarker panels to more accurately and precisely predict disease progression and response to therapy. This further allows for validation of diagnostic systems based on pathogenesis rather than amount and pattern of tissue destruction. Population-wide trans-OWAS integration (3) and deep learning identify and perpetually redefine phenotypes and refine by-phenotype biomarker panel array systems (4). This facilitates patient stratification for high predictive values of tests to determine disease susceptibility. Salivary screening for disease activity biomarkers classifies individuals as being at low, moderate or high risk for disease onset or progression. This allows for timely disease assessment and precise management by combining clinical examinations with further targeted salivary tests and pharmacogenomic analyses.

FIGURE 3

The evolution of diagnostic devices and wearable lab-on-a-chip’s (LOC) for precision medicine applications. (A): The most common diagnostic approaches to measuring soluble biomarkers are “sample-to-lab” and “lab-to-sample,” i.e., samples are either collected from patients, transferred to the lab and analyzed, or tests are delivered directly at the point-of-care for rapid actionable results in the clinic. Technological advancements of the 21st century allow for the development of LOC analyzers to gather diagnostic information chairside in real time. (B) The emerging integration of wearable LOC’s in health care allows for continuous monitoring of physiological and pathological processes, and provide dense individual-level data for Artificial Intelligence (AI)-assisted personalized management. The next Frontier in LOC development may be the fabrication of biocompatible implantable sensors for continuous measurement of soluble biomarkers difficult to measure through the skin. Such advancements will expand diagnostic capabilities, at-home care and telemedicine; (C): Example of a wearable biosensor integrated into a mouthguard to capture a single analyte in saliva over time and transduce the signal via Wi-Fi for analysis; (D): Example of a graphene-based nanosensor adhered to the tooth surface and marginal gingiva to capture and quantify multiple analytes over time. Data is processed onboard and deep learning algorithms applied to establish personal physiological thresholds and out of personal norm trends. Wirelessly transferred output data supports clinical decisions during in-office or teledentistry appointments.

FIGURE 4

Screening and SARS-CoV-2 point-of-care (POC) Testing for Oral health care (OHC) Decision Making and Serosurveillance. Screening and testing can provide actionable results at POC. COVID-19 screening and prevention protocols in OHC settings should be implemented within the clinical decision trees on delivery of elective or urgent care. Pre-appointment screenings via patient portals or mobile phone apps supplemented with in-house measurement of body temperature and POC testing can be the basis for safe practices and rational use of advanced personal protective equipment. This protocol first establishes who is at low-to-moderate risk (<65 years old, no known risk factors for severe disease outcome, no known exposure to individuals with active disease or recent travel to and from locations with outbreaks, no symptoms and temperature <100°F/37.8°C) vs. high-risk (>65 years old, existing risk factors for severe disease outcome, known exposure to individuals with active disease or travel to and from outbreak locations in the past 14 days, or present symptoms and body temperature >100°F/37.8°C). It then determines by testing if a patient was likely never infected, was previously infected and is immunized or is currently infected with SARS-CoV-2. Non-infected and immunized patients will benefit from both urgent and elective care. Infected asymptomatic should benefit from urgent care only with appropriate prevention measures. All treatments should be deferred for symptomatic infected individuals until recovery. Recovered COVID-19 patients with undetectable virus should benefit from urgent and elective care. Referral of positive cases to primary care physicians, and of immunized, but virus negative patients to blood donation, and contact tracing support will contribute to early management and control of disease spread.