HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Li, Y. Articles by Wong, D.T. Search for Related Content PubMed PubMed Citation Articles by Li, Y. Articles by Wong, D.T.

The Oral Fluid MEMS/NEMS Chip (OFMNC): Diagnostic & Translational Applications

Y. Li¹, P. Denny⁵, C.-M. Ho², C. Montemagno², W. Shi¹, F. Qi¹, B. Wu¹, L. Wolinsky¹, and D.T. Wong^1,*,3,4

¹ University of California, Los Angeles, School of Dentistry and Dental Research Institute, 73-017 CHS, 10833 Le Conte Ave., Los Angeles, CA 90095, USA;
² School of Engineering, ³ Jonsson Comprehensive Cancer Center, ⁴ Molecular Biology Institute, Los Angeles, CA, USA; and
⁵ University of Southern California, School of Dentistry, Los Angeles, CA, USA;

Correspondence: ^* corresponding author, dtww{at}ucla.edu

KEY WORDS: Oral fluid • saliva • MEMS/NEMS • proteomics • transcriptome diagnostics

The ability to monitor health status, disease onset and progression, and treatment outcome through non-invasive means is a most desirable goal in health-care promotion and delivery. There are three prerequisites for this goal to be realized: specific biomarkers associated with a health or disease state, a non-invasive approach to detect and monitor the biomarkers, and the technologies to discriminate between and among the biomarkers. We present a roadmap to achieve these goals using oral fluids as the diagnostic medium to scrutinize the health and/or disease status of individuals. This is an ideal opportunity to bridge state-of-the-art micro-/nano-electromechanical system (MEMS/NEMS) sensors to oral fluid for diagnostic applications. As the "mirror of body", oral fluid is a perfect medium to be explored for health and disease surveillance. The translational applications and opportunities are enormous.

	Introduction

TOP Introduction Vision and Challenges Saliva as a Diagnostic... Nanotechnology-based Salivary... Diagnostic Molecular Targets in... Roadmap of Salivary Diagnostics... References

 
The vision of the UCLA Collaborative Oral Fluid Diagnostic Research Center is to develop a non-invasive, single- or multiple-diseases point-of-care diagnostic platform, the ‘Oral Fluid MEMS/NEMS Chip’. This will have immense value in biomedical research as well as health-care delivery and promotion. A scientific vision and a network of expertise are in place to develop the science and propel the technologies necessary to validate saliva as a robust and reliable biofluid for definitive disease screening and diagnostics. This review is to highlight the research consortium, the diagnostic approach, and our roadmap to salivary diagnostics.

	Vision and Challenges

TOP Introduction Vision and Challenges Saliva as a Diagnostic... Nanotechnology-based Salivary... Diagnostic Molecular Targets in... Roadmap of Salivary Diagnostics... References

 
The post-genomic era provides opportunities for high-throughput approaches to genomics and proteomics. The novel technologies of miniaturization, coupled with the highly sensitive and specific detection technologies, create the possibility of radically new ways to detect and diagnose health and disease states in an individual, even in remote or impoverished settings. These discoveries and technological advances, in conjunction with the possibility for disease diagnostics via a non-invasive biofluid, would offer a revolutionary change in medicine.

There is a great need for convenient, accurate, and non-invasive point-of-care disease diagnostic tools. This is of particular relevance in the developing world, where many health risks and illnesses remain poorly defined and receive inappropriate treatment. In addition, little information about the burden of disease is available to guide population health decisions.

The vision and challenge of the UCLA Oral Fluid Diagnostic Research Center are to discover the diagnostic potential and optimize engineering technologies for the biofluid saliva (Fig. 1). The challenge is to establish the scientific foundation and clinical validations necessary to position salivary diagnostics to be a novel, accurate, and feasible technology to help us achieve definitive point-of-care assessment of individuals’ disease status. Inherent in this vision is the development of robust, simple-to-use biosensor technologies for reliable and valid clinical measures.

View larger version (34K): [in this window] [in a new window]   Fig. 1 — Disease markers’ manifestation in saliva and their detection by NEMS biosensors (OT-MNC).

• Point-of-care unequivocal identification of major diseases and/or pathogens
  
• Rapid diagnosis of exposure and disease
  
• Rapid detection of emerging pathogens
  
• Rapid parallel diagnosis of multiple diseases and infectious agents
  
• Accurate assessment of disease stage and prognosis
  
• Better detection and management of outbreaks and emerging acute and chronic health threats
  
• Quantification of disease incidence endemic to developing countries
  

Our research consortium is a multidisciplinary effort to achieve the goal to use saliva as a non-invasive biofluid for systemic disease diagnostics. The overall concept is revolutionary and, when successful, should change our current paradigm of disease diagnostics. While the idea is unconventional at this time, proof-of-principle data are in place to permit the full-scale exploration of this roadmap. We envision that, by 2007, definitive major human disease signatures will be harnessed from saliva and optimized to nanotechnology-based biosensors. An additional two years will lead to the dissemination of the developed technologies, to be available for health-care providers for point-of-care applications.

	Saliva as a Diagnostic Fluid

TOP Introduction Vision and Challenges Saliva as a Diagnostic... Nanotechnology-based Salivary... Diagnostic Molecular Targets in... Roadmap of Salivary Diagnostics... References

 
Saliva is a mirror of the body. The ability to utilize saliva to monitor the health and disease state of an individual is a highly desirable goal. However, saliva diagnostics is a ‘late bloomer’, since only recently has there been a growing appreciation of saliva as a mirror of the body which can reflect virtually the entire spectrum of normal and disease states (Mandel, 1993). These include tissue levels of natural substances and a large variety of molecules introduced for therapeutic, dependency, or recreational purposes, emotional status, hormonal status, immunological status, neurological effects, and nutritional and metabolic influences. A major drawback to the use of saliva as a diagnostic fluid has been the notion that informative analytes are generally present in lower amounts in saliva than in serum (Miller, 1994). With new and very sensitive techniques, the lower level of analytes in saliva is no longer a limitation. Almost anything one can measure in blood, one can measure in saliva. Saliva has been reliably used to detect HIV 1 and 2, and viral hepatitis A, B, and C. It can also be used to monitor an individual’s use of a variety of drugs, including marijuana, cocaine, and alcohol (Mandel, 1993).

There are compelling reasons to use saliva as a diagnostic fluid to monitor health and disease. It meets the demands for inexpensive, non-invasive, and easy-to-use diagnostic methods. As a clinical tool, saliva has many advantages over serum. Saliva is easy to collect, store, and ship, and it can be obtained at low cost in sufficient quantities for analysis. For patients, the non-invasive collection techniques dramatically reduce anxiety and discomfort and simplify procurement of repeated samples for longitudinal monitoring over time. For professionals, saliva collection is safer than blood tests, which could expose health-care providers to HIV or hepatitis virus. Saliva is also easier to handle for diagnostic procedures, since it does not clot, thus lessening the manipulations required. Saliva-based diagnostics is therefore more accessible, accurate, less expensive, and presents less risk to the patient than current methodologies.

	Nanotechnology-based Salivary Biosensors

TOP Introduction Vision and Challenges Saliva as a Diagnostic... Nanotechnology-based Salivary... Diagnostic Molecular Targets in... Roadmap of Salivary Diagnostics... References

 
Chih-Ming Ho and Carlo Montemagno at the UCLA School of Engineering are pioneers in the development of nanotechnology-based, nano-electrical-mechanical systems (NEMS) biosensors that exhibit exquisite sensitivity and specificity for analyte detection, down to the single molecule level (Soong et al., 2000; Huang et al., 2002). Our research consortium has established a firm and committed collaboration to the development of NEMS biosensors for the real-time, ultrasensitive, and ultraspecific detection of salivary diagnostic analytes. This multidisciplinary research network led to the formation of the ‘UCLA Collaborative Oral Fluid Diagnostic Research Center’. This is a robust forum of interactions between engineers and biologists/clinicians toward the development of NEMS biosensors for saliva-based disease diagnostics. Our engineering colleagues predict that, in a year, there will be ‘lab-on-a-chip’ prototypes available for research as well as patient applications (St. John et al., 2004). This saliva-based technology development initiative is funded by the National Institute of Dental & Craniofacial Research (NIDCR; UO1 DE15018; http://www.saliva.bme.ucla.edu).

	Diagnostic Molecular Targets in Saliva

TOP Introduction Vision and Challenges Saliva as a Diagnostic... Nanotechnology-based Salivary... Diagnostic Molecular Targets in... Roadmap of Salivary Diagnostics... References

 
To utilize the full diagnostic potential of saliva, one needs to decipher and catalogue the informative components comprehensively. Comparison of such a catalogue with a disease population will reveal diagnostic signatures that can discriminate between normal individuals and those with disease. The salivary proteome presents one such resource.

Our laboratory has recently made the discovery that discriminatory and diagnostic human mRNAs are present in the saliva of both normal and diseased individuals. The salivary transcriptome presents an additional valuable resource for disease diagnostics. Our first report of the salivary transcriptome demonstrated that the normal salivary transcriptome consists of ~ 3000 mRNAs (Li et al., 2004). Of particular value is that, of these 3000 mRNAs, 180 are common between different normal subjects, constituting the normal salivary transcriptome core (NSTC). To demonstrate the diagnostic and translation potential of the salivary transcriptome, investigators have profiled and analyzed saliva from head and neck cancer patients. Based on 4 mRNAs from the NSTC (IL8, OAZ1, SAT, and IL1B), they were able to discriminate and predict if a saliva sample was from a cancer or normal subject, with a combined sensitivity and specificity of 95% (Li et al., 2004b). While head and neck cancer was used as the first proof-of-principle disease for salivary transcriptome diagnostics, data are now available for systemic disease applications. Analysis of these data, while early and exploratory, provides sufficient confidence and demonstrated our competence to explore ‘Salivary Transcriptome Diagnostics’ fully for major human disease translational applications.

There are significant advantages in the use of transcriptome markers for disease diagnostics. The marker discovery process is high-throughput, with the use of genome-wide microarray platforms. While the human salivary proteome is still several years away, the normal salivary transcriptome has been completed and published (Li et al., 2004a). As a biomarker, RNA is as robust and as informative as any other analyte. Thus, salivary transcriptome offers the combined advantages of high-throughput marker discovery in a non-invasive biofluid with very high patient compliance. Highly diagnostic RNA signatures have been identified for head and neck cancer.

	Roadmap of Salivary Diagnostics for the 21st Century

TOP Introduction Vision and Challenges Saliva as a Diagnostic... Nanotechnology-based Salivary... Diagnostic Molecular Targets in... Roadmap of Salivary Diagnostics... References

 
The vision of our research consortium is to spearhead salivary diagnostics for major human diseases. An important related goal is to disseminate the discoveries and technologies for point-of-care definitive disease diagnostics. The ‘Roadmap of Salivary Diagnostics for 10 Major Human Diseases’ is the scientific journey to spearhead the continuum of research necessary to bridge and connect the various vital components of this research consortium, from patient recruitment, to discoveries (transcriptome and proteome), validations and clinical testing, translational applications, optimization to NEMS biosensors, technology dissemination and transfer, and product development. All of these components are in place, ready to shift into gear to activate the series of research projects necessary to drive the process forward (Fig. 2).

View larger version (35K): [in this window] [in a new window]   Fig. 2 — Roadmap of salivary diagnostics.

	Acknowledgments

 
This study was supported by PHS grants UO1 DE15018 and UO1 DE16275, and by a UCLA Jonsson Comprehensive Cancer Center Grant (D.T. Wong).

	References

TOP Introduction Vision and Challenges Saliva as a Diagnostic... Nanotechnology-based Salivary... Diagnostic Molecular Targets in... Roadmap of Salivary Diagnostics... References

 
Huang TJ, Liu M, Knight LD, Grody WW, Miller JF, Ho CM (2002). An electrochemical detection scheme for identification of single nucleotide polymorphisms using hairpin-forming probes. Nucleic Acids Res 30(12):e55.[Abstract/Free Full Text]

Li Y, Zhou X, St. John MA, Wong DT (2004a). RNA profiling of cell-free saliva using microarray technology. J Dent Res 83:199–203.[Abstract/Free Full Text]

Li Y, St John MA, Zhou X, Kim Y, Sinha U, Jordan RC, et al. (2004b). Salivary transcriptome diagnostics for oral cancer detection. Clin Cancer Res 10:8442–8450.[Abstract/Free Full Text]

Mandel ID (1993). Salivary diagnosis: more than a lick and a promise. J Am Dent Assoc 124:85–87; erratum 124:20–21.[Abstract]

Miller SM (1994). Saliva testing—a nontraditional diagnostic tool. Clin Lab Sci 7:39–44.[Medline]

Soong RK, Bachand GD, Neves HP, Olkhovets AG, Craighead HG, Montemagno CD (2000). Powering an inorganic nanodevice with a biomolecular motor. Science 290:1555–1558.[Abstract/Free Full Text]

St. John M, Li Y, Zhou X, Denny P, Ho C-M, Montemagno CD, et al. (2004). IL-6 and IL-8: potential biomarkers for oral cavity and oropharyngeal SCCA. Arch Otolaryngol Head Neck Surg 130:929–935.[Abstract/Free Full Text]

This article has been cited by other articles:

				M. Navazesh and S. K.S. Kumar Measuring salivary flow: Challenges and opportunities J Am Dent Assoc, May 1, 2008; 139(suppl_2): 35S - 40S. [Abstract] [Full Text] [PDF]

This Article Full Text (PDF) Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Li, Y. Articles by Wong, D.T. Search for Related Content PubMed PubMed Citation Articles by Li, Y. Articles by Wong, D.T.