Gold Nanorods Based Air Scanning Electron Microscopy and Diffusion Reflection Imaging for Mapping Tumor Margins in Squamous Cell Carcinoma

Nanochemistry of gold: from surface engineering to dental healthcare applications

Advancements in nanochemistry have led to the development of engineered gold nanostructures (GNSs) with remarkable potential for a variety of dental healthcare applications. These innovative nanomaterials offer unique properties and functionalities that can significantly improve dental diagnostics, treatment, and overall oral healthcare applications. This review provides an overview of the latest advancements in the design, synthesis, and application of GNSs for dental healthcare applications. Engineered GNSs have emerged as versatile tools, demonstrating immense potential across different aspects of dentistry, including enhanced imaging and diagnosis, prevention, bioactive coatings, and targeted treatment of oral diseases. Key highlights encompass the precise control over GNSs' size, crystal structure, shape, and surface functionalization, enabling their integration into sensing, imaging diagnostics, drug delivery systems, and regenerative therapies. GNSs, with their exceptional biocompatibility and antimicrobial properties, have demonstrated efficacy in combating dental caries, periodontitis, peri-implantitis, and oral mucosal diseases. Additionally, they show great promise in the development of advanced sensing techniques for early diagnosis, such as nanobiosensor technology, while their role in targeted drug delivery, photothermal therapy, and immunomodulatory approaches has opened new avenues for oral cancer therapy. Challenges including long-term toxicity, biosafety, immune recognition, and personalized treatment are under rigorous investigation. As research at the intersection of nanotechnology and dentistry continues to thrive, this review highlights the transformative potential of engineered GNSs in revolutionizing dental healthcare, offering accurate, personalized, and minimally invasive solutions to address the oral health challenges of the modern era.

Au nanodyes as enhanced contrast agents in wide field near infrared fluorescence lifetime imaging

The near-infrared (NIR) range of the electromagnetic (EM) spectrum offers a nearly transparent window for imaging tissue. Despite the significant potential of NIR fluorescence-based imaging, its establishment in basic research and clinical applications remains limited due to the scarcity of fluorescent molecules with absorption and emission properties in the NIR region, especially those suitable for biological applications. In this study, we present a novel approach by combining the widely used IRdye 800NHS fluorophore with gold nanospheres (GNSs) and gold nanorods (GNRs) to create Au nanodyes, with improved quantum yield (QY) and distinct lifetimes. These nanodyes exhibit varying photophysical properties due to the differences in the separation distance between the dye and the gold nanoparticles (GNP). Leveraging a rapid and highly sensitive wide-field fluorescence lifetime imaging (FLI) macroscopic set up, along with phasor based analysis, we introduce multiplexing capabilities for the Au nanodyes. Our approach showcases the ability to differentiate between NIR dyes with very similar, short lifetimes within a single image, using the combination of Au nanodyes and wide-field FLI. Furthermore, we demonstrate the uptake of Au nanodyes by mineral-oil induced plasmacytomas (MOPC315.bm) cells, indicating their potential for in vitro and in vivo applications.

Research Progress on Nanomaterials for Tissue Engineering in Oral Diseases

Due to their superior antibacterial properties, biocompatibility and high conductivity, nanomaterials have shown a broad prospect in the biomedical field and have been widely used in the prevention and treatment of oral diseases. Also due to their small particle sizes and biodegradability, nanomaterials can provide solutions for tissue engineering, especially for oral tissue rehabilitation and regeneration. At present, research on nanomaterials in the field of dentistry focuses on the biological effects of various types of nanomaterials on different oral diseases and tissue engineering applications. In the current review, we have summarized the biological effects of nanoparticles on oral diseases, their potential action mechanisms and influencing factors. We have focused on the opportunities and challenges to various nanomaterial therapy strategies, with specific emphasis on overcoming the challenges through the development of biocompatible and smart nanomaterials. This review will provide references for potential clinical applications of novel nanomaterials in the field of oral medicine for the prevention, diagnosis and treatment of oral diseases.

Nano-diagnostics as an emerging platform for oral cancer detection: Current and emerging trends

Globally, oral cancer kills an estimated 150,000 individuals per year, with 300,000 new cases being diagnosed annually. The high incidence rate of oral cancer among the South-Asian and American populations is majorly due to overuse of tobacco, alcohol, and poor dental hygiene. Additionally, socio-economic issues and lack of general awareness delay the primary screening of the disease. The availability of early screening techniques for oral cancer can help in carving out a niche for accurate disease prognosis and also its prevention. However, conventional diagnostic approaches and therapeutics are still far from optimal. Thus, enhancing the analytical performance of diagnostic platforms in terms of specificity and precision can help in understanding the disease progression paradigm. Fabrication of efficient nanoprobes that are sensitive, noninvasive, cost-effective, and less labor-intensive can reduce the global cancer burden. Recent advances in optical, electrochemical, and spectroscopy-based nano biosensors that employ noble and superparamagnetic nanoparticles, have been proven to be extremely efficient. Further, these sensitive nanoprobes can also be employed for predicting disease relapse after chemotherapy, when the majority of the biomarker load is eliminated. Herein, we provide the readers with a brief summary of conventional and new-age oral cancer detection techniques. A comprehensive understanding of the inherent challenges associated with conventional oral cancer detection techniques is discussed. We also elaborate on how nanoparticles have shown tremendous promise and effectiveness in radically transforming the approach toward oral cancer detection. This article is categorized under: Diagnostic Tools > Biosensing Diagnostic Tools > Diagnostic Nanodevices Diagnostic Tools > In Vitro Nanoparticle-Based Sensing.

Development of Radiotracers for Imaging of the PD-1/PD-L1 Axis

Immune checkpoint inhibitor (ICI) therapy has emerged as a major treatment option for a variety of cancers. Among the immune checkpoints addressed, the programmed death receptor 1 (PD-1) and its ligand PD-L1 are the key targets for an ICI. PD-L1 has especially been proven to be a reproducible biomarker allowing for therapy decisions and monitoring therapy success. However, the expression of PD-L1 is not only heterogeneous among and within tumor lesions, but the expression is very dynamic and changes over time. Immunohistochemistry, which is the standard diagnostic tool, can only inadequately address these challenges. On the other hand, molecular imaging techniques such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) provide the advantage of a whole-body scan and therefore fully address the issue of the heterogeneous expression of checkpoints over time. Here, we provide an overview of existing PET, SPECT, and optical imaging (OI) (radio)tracers for the imaging of the upregulation levels of PD-1 and PD-L1. We summarize the preclinical and clinical data of the different molecule classes of radiotracers and discuss their respective advantages and disadvantages. At the end, we show possible future directions for developing new radiotracers for the imaging of PD-1/PD-L1 status in cancer patients.

Gold nanomaterials for oral cancer diagnosis and therapy: Advances, challenges, and prospects

Early diagnosis and treatment of oral cancer are vital for patient survival. Since the oral cavity accommodates the second largest and most diverse microbiome community after the gut, the diagnostic and therapeutic approaches with low invasiveness and minimal damage to surrounding tissues are keys to preventing clinical intervention-related infections. Gold nanoparticles (AuNPs) are widely used in the research of cancer diagnosis and therapy due to their excellent properties such as surface-enhanced Raman spectroscopy, surface plasma resonance, controlled synthesis, the plasticity of surface morphology, biological safety, and stability. AuNPs had been used in oral cancer detection reagents, tumor-targeted therapy, photothermal therapy, photodynamic therapy, and other combination therapies for oral cancer. AuNPs-based noninvasive diagnosis and precise treatments further reduce the clinical intervention-related infections. This review is focused on the recent advances in research and application of AuNPs for early screening, diagnostic typing, drug delivery, photothermal therapy, radiotherapy sensitivity treatment, and combination therapy of oral cancer. Distinctive reports from the literature are summarized to highlight the latest advances in the development and application of AuNPs in oral cancer diagnosis and therapy. Finally, this review points out the challenges and prospects of possible applications of AuNPs in oral cancer diagnosis and therapy.

Safety Evaluation of Nanotechnology Products

Nanomaterials are now being used in a wide variety of biomedical applications. Medical and health-related issues, however, have raised major concerns, in view of the potential risks of these materials against tissue, cells, and/or organs and these are still poorly understood. These particles are able to interact with the body in countless ways, and they can cause unexpected and hazardous toxicities, especially at cellular levels. Therefore, undertaking in vitro and in vivo experiments is vital to establish their toxicity with natural tissues. In this review, we discuss the underlying mechanisms of nanotoxicity and provide an overview on in vitro characterizations and cytotoxicity assays, as well as in vivo studies that emphasize blood circulation and the in vivo fate of nanomaterials. Our focus is on understanding the role that the physicochemical properties of nanomaterials play in determining their toxicity.

Nanoparticles in Dentistry: A Comprehensive Review

In recent years, nanoparticles (NPs) have been receiving more attention in dentistry. Their advantageous physicochemical and biological properties can improve the diagnosis, prevention, and treatment of numerous oral diseases, including dental caries, periodontal diseases, pulp and periapical lesions, oral candidiasis, denture stomatitis, hyposalivation, and head, neck, and oral cancer. NPs can also enhance the mechanical and microbiological properties of dental prostheses and implants and can be used to improve drug delivery through the oral mucosa. This paper reviewed studies from 2015 to 2020 and summarized the potential applications of different types of NPs in the many fields of dentistry.

Formation of Large Intracellular Actin Networks Following Plasmonic Cell Fusion

Following fusion between two or more individual cells, the resulting cellular entity must undergo extensive restructuring of its plasma membrane and cytoskeleton in order to maintain its mechanical and physiological function. In artificial cell fusion that is executed by external triggering, such restructuring could be problematic due to the absence of preconditioning biological signals. In this work we study the reorganization of the actin filaments in adenocarcinoma cells that were fused using plasmonic triggering, i.e. the irradiation by resonant femtosecond laser pulses of cells specifically targeted by gold nanoparticles. Time-lapse confocal microscopy of the fusing cells has revealed the formation of large-scale actin networks that preserve the local orientations of the original actin cytoskeletons. The results confirm the local nature of the plasmonic interactions that were confined to the cells' plasma membranes and would help studying the development and dynamics of actin networks by offering a relatively stable, living cellular environment that supports large-scale actin growth.

Nanoparticles for Oral Cancer Diagnosis and Therapy

Oral cancer is the sixth most common malignant cancer, affecting the health of people with an unacceptably high mortality rate. Despite numerous clinical methods in the diagnosis and therapy of oral cancer (e.g., magnetic resonance imaging, computed tomography, surgery, and chemoradiotherapy), they still remain far from optimal. Therefore, an urgent need exists for effective and practical techniques of early diagnosis and effective therapy of oral cancer. Currently, various types of nanoparticles have aroused wide public concern, representing a promising tool for diagnostic probes and therapeutic devices. Their inherent physicochemical features, including ultrasmall size, high reactivity, and tunable surface modification, enable them to overcome some of the limitations and achieve the expected diagnostic and therapeutic effect. In this review, we introduce different types of nanoparticles that emerged for the diagnosis and therapy of oral cancers. Then, the challenges and future perspectives for nanoparticles applied in oral cancer diagnosis and therapy are presented. The objective of this review is to help researchers better understand the effect of nanoparticles on oral cancer diagnosis and therapy and may accelerate breakthroughs in this field.

Diffusion Reflection Method for Early Detection of Oral Squamous Cell Carcinoma Specifically Targeted by Circulating Gold-Nanorods Bio-Conjugated to Anti-Epidermal Growth Factor Receptor

BACKGROUND

Translation of nanomedical developments into clinical application is receiving an increasing interest. However, its use for oral squamous cell carcinoma (OSCC) diagnosis remains limited. We present an advanced nanophotonic method for oral cancer detection, based on diffusion reflection (DR) measurements of gold-nanorods bio-conjugated to anti-epidermal growth factor receptor (C-GNRs) specifically attached to OSCC cells.

OBJECTIVE

To investigate in a rat model of oral carcinogenesis the targeting potential of C-GNRs to OSCC by using the DR optical method.

MATERIALS AND METHODS

OSCC was induced by the carcinogen 4-nitroquinoline-N-oxide (4NQO). C-GNRs were introduced locally and systemically and DR measurements were recorded from the surface of the rat tongue following illumination with red laser beam. Rats were divided into experimental and control groups. The results were compared with the histologic diagnosis.

RESULTS

A total of 75 Wistar-derived rats were enrolled in the study. Local application did not reveal any statistical results. DR measurements following intravenous injection of C-GNRs revealed a significant increase in light absorption in rats with OSCC compare with rats without cancer (p<0.02, sensitivity 100%, specificity 89%). In addition, absorption of light increased significantly in cases of severe dysplasia and cancer (high risk) compared to rats without cancer and rats with mild dysplasia (low risk) (86% sensitivity and 89% specificity, AUC=0.79).

CONCLUSION

Combining nanotechnology and nanophotonics for in vivo diagnosis of OSCC serves as additional tier in the translation of advanced nanomedical developments into clinical applications. The presented method shows a promising potential of nanophotonics for oral cancer identification, and provides support for the use of C-GNRs as a selective drug delivery.

The Scattering of Gold Nanorods Combined with Differential Uptake, Paving a New Detection Method for Macrophage Subtypes Using Flow Cytometery

The strategy of identification for M1 and M2 macrophages both in vivo and in vitro would help to predict the health condition of the individual. Here, we introduced a solution to this problem with the advantage of both the phagocytic nature of macrophages and the scattering effect of gold nanorods (GNRs). The internalized GNRs, relating to their extent of intake, caused a conspicuous scattering profile at the red channel in flow cytometry, overruling the contribution of the cellular side scatters. This internalization is solely governed by the surface chemistry of GNRs. The PAH-GNRs showed maximum intake potency followed by Cit-, PSS-, and PEG-GNRs. On a substantial note, PAH-GNRs lead to differential uptake between M1 and M2 cells, with three times higher intake in M2 cells over M1. This is the first report of employing the scattering of unlabeled GNRs to discriminate M1 and M2 cell types using a flow cytometer.

Advanced diagnostic aids for oral cancer

Oral cancer, a universal malady, has become a stumbling block over the years due to its significant morbidity and mortality rates. The greater morbidity associated with this deadly disease is attributed to delay in its diagnosis / its presentation in advanced stage. Being multifactorial, Oral squamous cell carcinoma (OSCC) is the outcome of genetic and epigenetic instability. However, in many instances, oral cancer is preceded by precursor lesions named as oral potentially malignant disorders (OPMDs), the early detection of which makes it beneficial for patients with the possible increase in the productive longevity. Many diagnostic tools / aids have been explored with the aim of early detection of oral precancer and cancer. The basic chair-side procedures or relatively advanced aids come with a set of limitations along with subjectivity as one of the setbacks. The advent and exploitation of molecular techniques in the field of health diagnostics, is demanding the molecular typing of the OPMDs and also of oral cancer. The saga of various diagnostic aids for OSCC has witnessed the so-called latest trends such as lab-on-chip, microfluidics, nano diagnostics, liquid biopsy, omics technology and synthetic biology in early detection of oral precancer and cancer. Oral cancer being multifactorial in origin with the chief participation of altered genetics and epigenetics would demand high-end diagnostics for designing personalized therapy. Hence, the present paper highlights the role of various advanced diagnostic aids including 'omics' technology and synthetic biology in oral precancer and cancer.

Hyperlipidemic mice as a model for a real-time in vivo detection of atherosclerosis by gold nanorods-based diffusion reflection technique

Atherosclerosis (AS), the leading cause of morbidity and mortality in cardiovascular disease, needs an early detection for treatment and prevention of fatal events. Here, for the first time, we applied gold nanorods (GNRs)-assisted diffusion reflection (DR), a noninvasive technique for in vivo detection of AS in a high-fat-diet-induced c57bl mouse model, which resembles the manifestation of AS in humans. DR simply detects the change in light reflection profile of tissue due to the accumulation of GNRs in the AS plaques and enables clear detection of AS lesions in carotid and femoral arteries of these hyperlipidemic mice. After 24 hours post-GNRs injection, DR showed the highest efficiency of AS detection. Moreover, the sensitivity of the DR method is much higher than computed tomography (CT) and is comparable to ex vivo high-resolution CT. Our results strongly suggest that the DR method can detect early atherosclerotic lesions in a sensitive and specific manner.

Augmented tumor accumulation and photothermal ablation using gold nanoparticles with a particular cellular entry orientation

Gold nanoparticles with various functionalities have served as potential tools in nanotechnology for tumor ablation. In this work, we seek to design and develop gold nanoparticle with poly(ethylene glycol)-containing dopamine (hereafter termed as AuND), and to synthesize the AuND with one-sided Tat peptide expression (OT@AuND). We demonstrate the tumor cell-targeting ability on the basis of anti-nonspecific cell binding of OT@AuND and determine how the chemically modified gold nanoparticle–based product affects photothermal tumor therapy in vitro and in vivo. The OT@AuND with a particular cellular entry orientation–induced delayed endocytosis, which is advantageous for enhanced permeability and retention effect-based tumor accumulation. This is because the slower cellular interaction of OT@AuND allows it to have the time to be transported to and bind to the tumor site. In tumor cell lines, OT@AuND showed a lower cellular uptake than gold nanoparticles with full-sided Tat peptide expression (FT@AuND) in the early period (after its in vitro and in vivo administration), but the cellular internalization rate of OT@AuND caught up with that of FT@AuND in the late period. Importantly, the delayed cellular internalization feature of OT@AuND resulted in efficient tumor accumulation in tumor-bearing mice, because the time interval provided OT@AuND more chances not to bind to any cells, but to enter tumor cells, leading to selective photothermal tumor ablation. These data suggest that gold nanoparticles with a particular cellular entry orientation can be further explored as a potential photothermal therapeutic agent and as a strategy to treat tumors.

Optical method to extract the reduced scattering coefficient from tissue: theory and experiments

Tissues are considered challenging in terms of structure and composition analysis due to their tendency to multiple scatter the incident light. One of the most common theories for extracting optical properties of tissue is diffusion reflection (DR). In this Letter, we propose a new paradigm for estimating the reduced scattering coefficient of a medium from the reflected light phase. The technique is a modified DR theory wherein the phase is calculated by the product of the wavenumber and the average pathlength. This theory is supported by the reconstructed phase of tissue-like phantom experiments from an iterative algorithm.

Three-Dimensional Highly Sensitive Diffusion Reflection-Based Imaging Method for the in Vivo Localization of Atherosclerosis Plaques Following Gold Nanorods Accumulation

In this work, we present a novel, simple, and highly accurate three-dimensional (3D) diffusion reflection (DR) imaging system and method for the detection of accumulation sites of gold nanorods (GNRs) within the tissue. GNRs are intensively used for diagnosis purposes of varied diseases, mainly because of their ability to well absorb visible light, which introduces them as terrific contrast agents in various imaging and theranostics methods. Lately, these GNRs unique absorption properties have served in DR intensity-based measurements, suggesting a novel diagnostic tool, DR-GNRs. In this paper, we show a new measurement system and method for DR, based on its radial collection from the tissue. These radial measurements enabled a unique 3D presentation of the DR-GNR, introducing the dimensions ρ for the radius, θ for the angle, and Γ for the reflected intensity. On the basis of the diffusion model, which enables to correlate between the sample's optical properties and its reflectance, a unique, radial map is presented. This map introduces the slopes of the DR curves in each measured angle, which are linearly correlated with the tissue's optical properties and with the GNRs concentrations within the tissue, thus enables the exact radial localization of the GNRs in the sample. We show the detection of macrophage accumulation in tissue-like phantoms, as well as the localization of unstable plaques in hyperlipidemic mice, in vivo. This highly accurate, powerful technology paves the way toward a real-time detection method that can be successfully integrated in the rapid increasing field of personalized medicine.

Nanotechnology: a promising method for oral cancer detection and diagnosis

Oral cancer is a common and aggressive cancer with high morbidity, mortality, and recurrence rate globally. Early detection is of utmost importance for cancer prevention and disease management. Currently, tissue biopsy remains the gold standard for oral cancer diagnosis, but it is invasive, which may cause patient discomfort. The application of traditional noninvasive methods-such as vital staining, exfoliative cytology, and molecular imaging-is limited by insufficient sensitivity and specificity. Thus, there is an urgent need for exploring noninvasive, highly sensitive, and specific diagnostic techniques. Nano detection systems are known as new emerging noninvasive strategies that bring the detection sensitivity of biomarkers to nano-scale. Moreover, compared to current imaging contrast agents, nanoparticles are more biocompatible, easier to synthesize, and able to target specific surface molecules. Nanoparticles generate localized surface plasmon resonances at near-infrared wavelengths, providing higher image contrast and resolution. Therefore, using nano-based techniques can help clinicians to detect and better monitor diseases during different phases of oral malignancy. Here, we review the progress of nanotechnology-based methods in oral cancer detection and diagnosis.

Self-Calibration Phenomenon for Near-Infrared Clinical Measurements: Theory, Simulation, and Experiments

An irradiated turbid medium scatters the light in accordance to its optical properties. Near-infrared (NIR) clinical methods, which are based on spectral-dependent absorption, suffer from an inherent error due to spectral-dependent scattering. We present here a unique spatial point, that is, iso-pathlength (IPL) point, on the surface of a tissue at which the intensity of re-emitted light remains constant. This scattering-indifferent point depends solely on the medium geometry. On the basis of this natural phenomenon, we suggest a novel optical method for self-calibrated clinical measurements. We found that the IPL point exists in both cylindrical and semi-infinite tissue geometries (Supporting Information, Video file). Finally, in vivo human finger and mice measurements are used to validate the crossing point between the intensity profiles of two wavelengths. Hence, measurements at the IPL point yield an accurate absorption assessment while eliminating the scattering dependence. This finding can be useful for oxygen saturation determination, NIR spectroscopy, photoplethysmography measurements, and a wide range of optical sensing methods for physiological aims.

Fast Image-Guided Stratification Using Anti-Programmed Death Ligand 1 Gold Nanoparticles for Cancer Immunotherapy

Cancer immunotherapy has made enormous progress in offering safer and more effective treatments for the disease. Specifically, programmed death ligand 1 antibody (αPDL1), designed to perform immune checkpoint blockade (ICB), is now considered a pillar in cancer immunotherapy. However, due to the complexity and heterogeneity of tumors, as well as the diversity in patient response, ICB therapy only has a 30% success rate, at most; moreover, the efficacy of ICB can be evaluated only two months after start of treatment. Therefore, early identification of potential responders and nonresponders to therapy, using noninvasive means, is crucial for improving treatment decisions. Here, we report a straightforward approach for fast, image-guided prediction of therapeutic response to ICB. In a colon cancer mouse model, we demonstrate that the combination of computed tomography imaging and gold nanoparticles conjugated to αPDL1 allowed prediction of therapeutic response, as early as 48 h after treatment. This was achieved by noninvasive measurement of nanoparticle accumulation levels within the tumors. Moreover, we show that the nanoparticles efficiently prevented tumor growth with only a fifth of the standard dosage of clinical care. This technology may be developed into a powerful tool for early and noninvasive patient stratification as responders or nonresponders.

Nanotechnology in oral cancer: A comprehensive review

Oral health could be maintained by application of this technology in prevention, diagnosis and treatment. Oral cancer is a debilitating disease, and numerous research activities are being pursued worldwide to combat this deleterious process. Nanotechnology is very diverse field that has revolutionized the industry and is setting new trends in the management of oral cancer. Hence, we performed a PubMed search on nanotechnology in oral cancer and found 211 articles related to this search. We have reviewed the reported literature to the best of our abilities and summarized the various aspects of nanotechnology, its role in diagnosis - nanodiagnostics and treatment of oral cancer - nanotherapeutics in this article.

Future trends and emerging issues for nanodelivery systems in oral and oropharyngeal cancer

Oral cancer is a prevalent cancer type on a global scale, whose traditional treatment strategies have several drawbacks that could in the near future be overcome through the development of novel therapeutic and prognostic strategies. Nanotechnology provides an alternative to traditional therapy that leads to enhanced efficiency and less toxicity. Various nanosystems have been developed for the treatment of oral cancer, including polymeric, metallic, and lipid-based formulations that incorporate chemotherapeutics, natural compounds, siRNA, or other molecules. This review summarizes the main benefits of using these nanosystems, in parallel with a particular focus on the issues encountered in medical practice. These novel strategies have provided encouraging results in both in vitro and in vivo studies, but few have entered clinical trials. The use of nanosystems in oral cancer has the potential of becoming a valid therapeutic option for patients suffering from this malignancy, considering that clinical trials have already been completed and others are currently being developed.

Gold nanorods reflectance discriminate benign from malignant oral lesions

Nanoparticle-based contrast agents have been used as an imaging tool for selectively detecting cancerous processes. We aimed to evaluate the detection sensitivity of reflection measurements of gold nanorods (GNRs) bio-conjugated to anti-epidermal growth factor receptor (GNRs-EGFR) monoclonal antibodies in discriminating benign from premalignant and malignant human oral lesions. Tissue sections incubated with GNRs-EGFR and the reflectance spectrum was measured using hyperspectral microscopy. Reflectance intensity increased with the progression of the disease, lowest in the control group and increasing as the dysplastic changes increase (P<0.001 for linear trend of grade). Intensity was significantly higher in the moderate and severe dysplasias and cancer patients than in the controls and mild dysplasia (t test P=0.0003, Mann-Whitney P<0.0001). The GNRs reflection measurements can discriminate benign and mild dysplastic lesions from the more severe dysplasia and invasive cancer, suggesting an objective, not dependent on the qualification of a technician and with less interpretation errors.

Extremely sensitive dual imaging system in solid phantoms

Herein we describe promising results from the combination of fluorescent lifetime imaging microscopy (FLIM) and diffusion reflection (DR) medical imaging techniques. Three different geometries of gold nanoparticles (GNPs) were prepared: spheres of 20nm diameter, rods (GNRs) of aspect ratio (AR) 2.5, and GNRs of AR 3.3. Each GNP geometry was then conjugated using PEG linkers estimated to be 10nm in length to each of 3 different fluorescent dyes: Fluorescein, Rhodamine B, and Sulforhodamine B. DR provided deep-volume measurements (up to 1cm) from within solid, tissue-imitating phantoms, indicating GNR presence corresponding to the light used by recording light scattered from the GNPs with increasing distance to a photodetector. FLIM imaged solutions as well as phantom surfaces, recording both the fluorescence lifetimes as well as the fluorescence intensities. Fluorescence quenching was observed for Fluorescein, while metal-enhanced fluorescence (MEF) was observed in Rhodamine B and Sulforhodamine B - the dyes with an absorption peak at a slightly longer wavelength than the GNP plasmon resonance peak. Our system is highly sensitive due to the increased intensity provided by MEF, and also because of the inherent sensitivity of both FLIM and DR. Together, these two modalities and MEF can provide a lot of meaningful information for molecular and functional imaging of biological samples.