Handheld Optical Device Research Articles

Retinal imaging with hand-held optical coherence tomography in older people with or without postoperative delirium after hip fracture surgery: A feasibility study.

Postoperative delirium in older people may result from the interaction between intrinsic brain vulnerability (e.g. neurodegeneration) and precipitating factors (e.g. surgery induced cytokines). Intrinsic brain vulnerability may be overt (e.g. Alzheimer's disease) or preclinical. In cognitively intact older people presenting for surgery, identification of preclinical neurodegeneration using bedside tools could aid postoperative delirium risk stratification. Thinning of the circumpapillary retinal nerve fibre layer thickness is associated with neurodegenerative disorders e.g. Alzheimer's disease. We propose that thinning of the retinal nerve fibre layer may be present some older people with postoperative delirium due to preclinical neurodegeneration, albeit to a lesser extent than in overt dementia. The primary objective: Feasibility of acquiring usable retinal images with the hand-held optical coherence device, at the bedside of older, hip fracture surgery patients. Secondary objective: Comparison of the circumpapillary retinal nerve fibre layer thickness between people who did/did not have postoperative delirium. Proportion of exclusions due to retinal pathology. Feasibility study involving 30, cognitively intact, older people recovering from hip fracture surgery. Retinal images were obtained using the hand-held optical coherence tomography device at the participants' bedside. Imaging was deferred in participants who had postoperative delirium. Retinal images that could be assessed for circumpapillary retinal nerve fibre layer thickness were obtained in 26 participants (22 no postoperative delirium, 4 postoperative delirium). The mean circumpapillary retinal nerve fibre layer thickness was lower in the participants who had postoperative delirium compared to those who did not experience postoperative delirium (Mean (95% CI) of 76.50 (62.60-90.40) vs 89.19 (85.41-92.97) respectively). Retinal imaging at the patient's bedside, using hand-held OCT is feasible. Our data suggests that the circumpapillary retinal nerve fibre layer may be thinner in older people who experience postoperative delirium compared to those who do not. Further studies are required.

Respiratory distress syndrome prediction at birth by optical skin maturity assessment and machine learning models for limited-resource settings: a development and validation study.

A handheld optical device was developed to evaluate a newborn's skin maturity by assessing the photobiological properties of the tissue and processing it with other variables to predict early neonatal prognosis related to prematurity. This study assessed the device's ability to predict respiratory distress syndrome (RDS). To assess the device's utility we enrolled newborns at childbirth in six urban perinatal centers from two multicenter single-blinded clinical trials. All newborns had inpatient follow-up until 72 h of life. We trained supervised machine learning models with data from 780 newborns in a Brazilian trial and provided external validation with data from 305 low-birth-weight newborns from another trial that assessed Brazilian and Mozambican newborns. The index test measured skin optical reflection with an optical sensor and adjusted acquired values with clinical variables such as birth weight and prenatal corticoid exposition for lung maturity, maternal diabetes, and hypertensive disturbances. The performance of the models was evaluated using intrasample k-parts cross-validation and external validation in an independent sample. Models adjusting three predictors (skin reflection, birth weight, and antenatal corticoid exposure) or five predictors had a similar performance, including or not maternal diabetes and hypertensive diseases. The best global accuracy was 89.7 (95% CI: 87.4 to 91.8, with a high sensitivity of 85.6% (80.2 to 90.0) and specificity of 91.3% (95% CI: 88.7 to 93.5). The test correctly discriminated RDS newborns in external validation, with 82.3% (95% CI: 77.5 to 86.4) accuracy. Our findings demonstrate a new way to assess a newborn's lung maturity, providing potential opportunities for earlier and more effective care. RBR-3f5bm5 (online access: http://www.ensaiosclinicos.gov.br/rg/RBR-3f5bm5/), and RBR-33mjf (online access: https://ensaiosclinicos.gov.br/rg/RBR-33rnjf/).

Establishment of a fiber optic sensor coupled to the plasmonic effect of silver nanoparticles in glucose concentration monitoring

Introduction: Diabetes is an extremely dangerous disease due to the disorder of glucose metabolism in the body leading to serious complications and the cause other dangerous diseases. Therefore, the continuous monitoring of glucose levels in the body is particularly important in the prevention and treatment of this disease. Optical fiber sensors that apply the LSPR effect of silver nanoparticles show great potential in the field of sensors that enable precise label-free monitoring of analyte concentrations with high sensitivity, which is receiving much attention. Methods: Based on the sensitivity of the LSPR effect on the surface of AgNPs to the dielectric properties of the medium, namely the refractive index of the analyte solution. Variation in the LSPR conditions of AgNPs leads to either donation or reduction in optical power. Based on that mechanism, the fiber was used as a waveguide and was immobilized on a self-assembled monolayer of AgNPs 1 core surrounded by a microfluidic channel that allows the analyte solution to pass through the sensing area through a biological pump. This process of changing the capacity allows the assessment of glucose concentration in solution to a very small degree of change. Results: AgNPs of about 90 nm in size were quickly and simply synthesized with high stability and uniformity by chemical reduction with an Ethylene glycol reducing agent as demonstrated by FESEM, and DLS results. The LSPR wavelength of AgNPs solution observed by UV-vis spectrum is 435 nm. At the same time, a fiber-optic sensor system that monitors glucose concentration changes has also been successfully established with a sensitivity of 0.025 RIU corresponding to a detection of limited (LOD) of up to 0.35 mM. Conclusions: The optical fiber optical sensor based on the LSPR phenomenon of AgNPs was initially established and showed high sensitivity in detecting and monitoring changes in glucose concentration without the use of complex markers or enzymes. The compact size of the fiber sensor opens up the potential for integration into handheld optical devices to help monitor health more proactively. Keywords: Silver nanoparticles, LSPR, Glucose sensor, optical sensor, detection of limited.

Optical Biosensors for Diagnostics of Infectious Viral Disease: A Recent Update.

The design and development of biosensors, analytical devices used to detect various analytes in different matrices, has emerged. Biosensors indicate a biorecognition element with a physicochemical analyzer or detector, i.e., a transducer. In the present scenario, various types of biosensors have been deployed in healthcare and clinical research, for instance, biosensors for blood glucose monitoring. Pathogenic microbes are contributing mediators of numerous infectious diseases that are becoming extremely serious worldwide. The recent outbreak of COVID-19 is one of the most recent examples of such communal and deadly diseases. In efforts to work towards the efficacious treatment of pathogenic viral contagions, a fast and precise detection method is of the utmost importance in biomedical and healthcare sectors for early diagnostics and timely countermeasures. Among various available sensor systems, optical biosensors offer easy-to-use, fast, portable, handy, multiplexed, direct, real-time, and inexpensive diagnosis with the added advantages of specificity and sensitivity. Many progressive concepts and extremely multidisciplinary approaches, including microelectronics, microelectromechanical systems (MEMSs), nanotechnologies, molecular biology, and biotechnology with chemistry, are used to operate optical biosensors. A portable and handheld optical biosensing device would provide fast and reliable results for the identification and quantitation of pathogenic virus particles in each sample. In the modern day, the integration of intelligent nanomaterials in the developed devices provides much more sensitive and highly advanced sensors that may produce the results in no time and eventually help clinicians and doctors enormously. This review accentuates the existing challenges engaged in converting laboratory research to real-world device applications and optical diagnostics methods for virus infections. The review’s background and progress are expected to be insightful to the researchers in the sensor field and facilitate the design and fabrication of optical sensors for life-threatening viruses with broader applicability to any desired pathogens.

(Invited) Low Cost Paper Based Bilirubin Sensor Integrated with Smartphone APP for Point-of-Care Neonatal and Adult Jaundice Diagnostics

Accumulation of excessive bilirubin induces hyperbilirubinemia and neonatal jaundice, and is a signal of adult liver diseases. Currently, the mainstream bilirubin detection is conducted in hospital pathological laboratories, which is expensive and time-consuming. To release the heavy burden of laboratory-based tests and to provide point-of-care testing and feedback to patients, recently some handheld optical devices have been developed for blood bilirubin measurement; however, they still require professional operation and uneconomical for home use. In this regard, a lower-cost and non-powered paper-based analytical device is developed for fast and point-of-care quantitative measurement of blood bilirubin levels in jaundiced neonates and hepatopathy adults. The design achieves plasma separation from whole blood and optical quantification of the chromogenic results by a specially designed smartphone APP. Especially, for jaundiced neonates, the APP not only calculates the bilirubin levels but also suggests the essential therapy if the detected bilirubin level versus the age of the baby is at risk. It is believed that this low-cost design provides a home-use solution for parents/patients to monitor the health conditions of newborn babies/themselves.

MP25-12 HANDHELD OPTICAL DEVICE DETECTS BACTERIURIA AND CATHETER-ASSOCIATED URINARY TRACT INFECTION

You have accessJournal of UrologyInfections/Inflammation/Cystic Disease of the Genitourinary Tract: Kidney & Bladder I (MP25)1 Sep 2021MP25-12 HANDHELD OPTICAL DEVICE DETECTS BACTERIURIA AND CATHETER-ASSOCIATED URINARY TRACT INFECTION Rena Malik, and Rajagopal Srinivasan Rena MalikRena Malik More articles by this author , and Rajagopal SrinivasanRajagopal Srinivasan More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002022.12AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Traditional diagnostic tests cannot discriminate asymptomatic bacteriuria (ASB) from catheter-associated urinary tract infection (CAUTI). High false-positive rates with current tests lead to excessive antibiosis, drug resistance, and worse outcomes in the chronically-catheterized. We are evaluating a handheld optical device’s ability to distinguish ASB from CAUTI. METHODS: normal, POSitive (confirmed UTI), and COLonized catheters with varying rates of ASB. Spectra were analyzed using principal component analysis (PCA). RESULTS: Of 68 specimens, 37 were classified beyond reasonable doubt by physician review of clinical details and culture results. 18 were NEG, 5 were POS, and 14 were COL. Mean spectra and standard deviations for each category are plotted in Fig. 1. PCA reveals clustering of POS, NEG, and COL signals (Fig. 2). Using a simple discriminant along the horizontal axis, sensitivity is 80% and specificity is 91%. CONCLUSIONS: Spectroscopy can predict negative culture results and help distinguish ASB from CAUTI. Source of Funding: Investigators were supported by grants from UMEMA PA and Maryland Innovation Initiative. © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e457-e458 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Rena Malik More articles by this author Rajagopal Srinivasan More articles by this author Expand All Advertisement Loading ...

A comparison of different optical instruments and machine learning techniques to identify sprouting activity in potatoes during storage

The quality of potato tubers is dependent on several attributes been maintained at appropriate levels during storage. One of these attributes is sprouting activity that is initiated from meristematic regions of the tubers (eyes). Sprouting activity is a major problem that contributes to reduced shelf life and elevated sugar content, which affects the marketability of seed tubers as well as fried products. This study compared the capabilities of three different optical systems (1: visible/near-infrared (Vis/NIR) interactance spectroscopy, 2: Vis/NIR hyperspectral imaging, 3: NIR transmittance) and machine learning methods to detect sprouting activity in potatoes based on the primordial leaf count (LC). The study was conducted on Frito Lay 1879 and Russet Norkotah cultivars stored at different temperatures and classification models were developed that considered both cultivars combined and classified the tubers as having either high or low sprouting activity. Measurements were performed on whole tubers and sliced samples to see the effect this would have on identifying sprouting activity. Sequential forward selection was applied for wavelength selection and the classification was carried out using K-nearest neighbor, partial least squares discriminant analysis, and soft independent modeling class analogy. The highest classification accuracy values obtained by the hyperspectral imaging system and was 87.5% and 90% for sliced and whole samples, respectively. Data fusion did not show classification improvement for whole tubers, whereas a 7.5% classification accuracy increase was illustrated for sliced samples. By investigating different optical techniques and machine learning methods, this study provides a first step toward developing a handheld optical device for early detection of sprouting activity, enabling advanced aid potato storage management.

Dielectric Nanoaperture Metasurfaces in Silicon Waveguides for Efficient and Broadband Mode Conversion with an Ultrasmall Footprint

AbstractEfficient and reliable mode converters with broadband operation and small footprint will enable high‐density silicon photonic integrated circuits to build high bitrate optical networks and handheld optical devices. Here, all‐dielectric nanoaperture metasurfaces in the silicon layer of a silicon‐on‐insulator platform are reported for mode‐order conversion with an ultrasmall footprint. Utilizing the advantages of an abrupt width change and metasurface, the mode conversion between TE00 and TE10 modes is realized with a conversion efficiency as high as ≈90% in simulations and 83.1% in experiments at λ = 1.55 µm within an ultrashort conversion length of about 2.42 µm, the shortest ever achieved. The incident TE00 mode is converted to TE10 mode with purity of more than 90% in a broadband (Δλ ≈ 230 nm) wavelength range from 1.42 to 1.65 µm. Moreover, optimizing the number, position, and dimension of nanoapertures, it is further demonstrated that the nanoaperture metasurface design can enable mode conversion between silicon waveguides of different thicknesses and different relative positions, and between TM modes.

Noninvasive surface imaging of breast cancer in humans using a hand-held optical imager

X-ray mammography, the current gold standard for breast cancer detection, has a 20% false-negative rate (cancer is undetected) and increases in younger women with denser breast tissue. Diffuse optical imaging is a safe (nonionizing), and relatively inexpensive method for noninvasive imaging of breast cancer in human subjects (including dense breast tissues) by providing physiological information (e.g. oxy- and deoxy- hemoglobin concentration). At the Optical Imaging Laboratory, a hand-held optical imager has been developed which employs a breast contourable probe head to perform simultaneous illumination and detection of large surfaces towards near real-time imaging of human breast cancer. First generation (gen-1) and second generation (gen-2) versions of the hand-held optical imager have been developed and previously demonstrated imaging in tissue phantoms and healthy human subjects. Herein, the hand-held optical imagers are applied towards in vivo imaging of breast cancer subjects in an attempt to determine the ability of the imager to detect breast tumors. Five female human subjects (ages 51–74) diagnosed with breast cancer were imaged with the gen-1 optical imager prior to surgical intervention. One of the subjects was also imaged with the gen-2 optical imager. Both imagers use 785 nm laser diode sources and intensified charge-coupled device camera detectors to generate 2D surface maps of total hemoglobin absorption. The subjects lay in supine position and images were collected at various locations on both the ipsilateral (tumor-containing) and contralateral (non-tumor containing) breasts. The optical images (2D surface maps of optical absorption due to total hemoglobin concentration) show regions of higher intensity at the tumor location, which is indicative of increased vasculature and higher blood content due to the presence of the tumor. Additionally, a preliminary result indicates the potential to image lymphatic spread. This study demonstrates the potential of the hand-held optical devices to noninvasively image breast cancer in human subjects.

Handheld Optical System for Skin Topography Measurement Using Fourier Transform Profilometry

In medicine and cosmetics a need has arisen for an accurate, fast, simple and broadly applicable three-dimensional skin surface measuring system. A new development of such handheld optical device that uses white light Fourier transform profilometry for skin surface topography measurement is presented here. The device is based on a commercially available DSLR camera and a newly designed optical system which projects a Ronchi grating pattern on the measured surface and records its image. The 3D surface is reconstructed from a single image. The topography is described using four surface roughness parameters: mean absolute deviation Ra, root-mean-square deviation Rq skewness Rsk and kurtosis Rku. Experimental measurements were conducted on five facial skin areas, together belonging to three people, before and after the laser skin treatment therapy, to evaluate its effects on skin surface roughness. The results show the viability and usefulness of the developed optical system for skin topography measurement.

Fluorescence-optical handheld non-contact sensor for rapid cleaning validation of surfaces

AbstractBackground and objective:Thin films of bacteria, proteins and other biochemical substances are always found on surfaces exposed to the environment. Optical methods enable innovative tools for the detection of such films, as residua of proteins and other substances that exhibit fluorescence when excited with UV light.Sensor design:This paper presents and evaluates a specially designed handheld measuring device for this purpose.Results:The sensor is able to detect low concentrations of organic contamination with measurement times shorter than a second. The results presented in this paper show that detection of contamination levels of bovine serum albumin down to 200 ng/cmConclusion:Future development of handheld optical devices suitable for the detection or analysis of various compounds could be based on these results.

Selective use of sequential digital dermoscopy imaging allows a cost reduction in the melanoma detection process: a belgian study of patients with a single or a small number of atypical nevi.

BackgroundDermoscopy is a technique which improves melanoma detection. Optical dermoscopy uses a handheld optical device to observe the skin lesions without recording the images. Sequential digital dermoscopy imaging (SDDI) allows storage of the pictures and their comparison over time. Few studies have compared optical dermoscopy and SDDI from an economic perspective.ObjectiveThe present observational study focused on patients with one-to-three atypical melanocytic lesions, i.e. lesions considered as suspicious by optical dermoscopy. It aimed to calculate the “extra-costs” related to the process of melanoma detection. These extra-costs were defined as the costs of excision and pathology of benign lesions and/or the costs of follow-up by SDDI. The objective was to compare these extra-costs when using optical dermoscopy exclusively versus optical dermoscopy with selective use of SDDI.MethodsIn a first group of patients, dermatologists were adequately trained in optical dermoscopy but worked without access to SDDI. They excised all suspicious lesions to rule out melanoma. In a second group, the dermatologists were trained in optical and digital dermoscopy. They had the opportunity of choosing between immediate excision or follow-up by SDDI (with delayed excision if significant change was observed). The comparison of extra-costs in both groups was made possible by a decision tree model and by the division of the extra-costs by the number of melanomas diagnosed in each group. Belgian official tariffs and charges were used.ResultsThe extra-costs in the first and in the second group were respectively €1,613 and €1,052 per melanoma excised. The difference was statistically significant.ConclusionsUsing the Belgian official tariffs and charges, we demonstrated that the selective use of SDDI for patients with one-to-three atypical melanocytic lesions resulted in a significant cost reduction.

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Setting-up of a simplified handheld optical device for decay detection in fresh-cut Valerianella locusta L.

The aim of this work was to study the feasibility of a simplified handheld and low-cost optical device. This study was focused on identifying the most significant vis/NIR wavelengths able to discriminate freshness levels during shelf-life of fresh-cut Valerianella locusta L.The shelf-life of Valerianella leaves was monitored using a portable commercial vis/NIR spectrophotometer and by traditional analyses (pH, moisture and total phenols content). The Valerianella samples were stored at three temperature: 4°C, 10°C, and 20°C. Through PLS-RCA technique, standardized regression coefficients of PLS models were used to select the relevant variables, representing the most useful information of full spectral region. The four selected wavelengths were 520nm, 680nm, 710nm and 720nm. Multiple linear regression was applied in order to verify the effectiveness of selected wavelengths. Results demonstrate the feasibility of a simplified device for quickly monitoring the shelf-life of fresh-cut Valerianella leaves.

Derivation of a Blueberry Ripeness Index with a View to a Low-Cost, Handheld Optical Sensing Device for Supporting Harvest Decisions

Abstract. Berry fruit farming and marketing have widely increased in recent years in marginal areas of Italy, especially in response to consumers’ growing interest in adhering to a bioactive and health-protecting diet. The ripening stage of berry fruits, on which their quality and nutraceutical attributes depend, is typically estimated by growers through visual inspection based on the growers’ experience. Low-cost, handheld, user-friendly devices could assist growers in the field in determining the optimal harvest date in accordance with the desired ripeness of berries. In order to explore the technical feasibility of such a system, this study focused on defining a simple ripeness index for blueberries by identifying the main spectral changes accompanying their ripening process, with special attention paid to the last and most relevant stages. With this aim, spectral measurements in the range of 445 to 970 nm were carried out on Vaccinium corymbosum (cv. Brigitta) during two different growing seasons. Spectra were acquired on 942 individual berries in the field at different dates. Measurements were accompanied by weekly samplings, with picked fruits divided into four ripeness grades according to commercial growers’ classification. A principal component analysis of fruit spectra highlighted that two main wavebands (680 and 740 nm) can maximize the differences between fully ripe samples and those close to ripeness or unripe. Hence, spectral values at 680, 740, and 850 nm (the latter being an additional normalization waveband) were used to create a blueberry ripeness index (BRI) as a linear combination of two spectral ratios: S1 = log(I680/I850) and S2 = (I740/I850). The definition of specific ripeness thresholds for the BRI according to more or less selective criteria was illustrated in an application example, and the ripeness classification capability was then assessed on a separate validation set of 471 berries. When applying a less selective threshold approach, the BRI correctly classified as ripe 85% of manually graded fully ripe berries, whereas 13% of close but not yet ripe validation samples were misclassified as fully ripe and ready to harvest. Comparatively, when a more demanding ripeness threshold was applied, the amount of nearly ripe berries misclassified as ripe decreased to 8%, but the amount of fully ripe berries not identified as ripe rose to 25%. In both cases, none of the unripe validation samples was erroneously classified as ripe fruit. These results, which were obtained with a BRI defined by spectral measurements at just three discrete wavelengths, point to the feasibility of a simple, microcontroller-based, handheld optical device able to implement the BRI to quickly assess the ripeness of sets of berries during the last and most delicate stages of the ripening process.

Single-pipetting microfluidic assay device for rapid detection of Salmonella from poultry package

A direct, sensitive, near-real-time, handheld optical immunoassay device was developed to detect Salmonella typhimurium in the naturally occurring liquid from fresh poultry packages (hereafter “chicken matrix”), with just single pipetting of sample (i.e., no filtration, culturing and/or isolation, thus reducing the assay time and the error associated with them). Carboxylated, polystyrene microparticles were covalently conjugated with anti-Salmonella, and the immunoagglutination due to the presence of Salmonella was detected by reading the Mie scatter signals from the microfluidic channels using a handheld device. The presence of chicken matrix did not affect the light scatter signal, since the optical parameters (particle size d, wavelength of incident light λ and scatter angle θ) were optimized to minimize the effect of sample matrix (animal tissues and blood proteins, etc.). The sample was loaded into a microfluidic chip that was split into two channels, one pre-loaded with vacuum-dried, antibody-conjugated particles and the other with vacuum-dried, bovine serum albumin-conjugated particles. This eliminated the need for a separate negative control, effectively minimizing chip-to-chip and sample-to-sample variations. Particles and the sample were diffused in-channel through chemical agitation by Tween 80, also vacuum-dried within the microchannels. Sequential mixing of the sample to the reagents under a strict laminar flow condition synergistically improved the reproducibility and linearity of the assay. In addition, dried particles were shown to successfully detect lower Salmonella concentrations for up to 8 weeks. The handheld device contains simplified circuitry eliminating unnecessary adjustment stages, providing a stable signal, thus maximizing sensitivity. Total assay time was 10min, and the detection limit 10CFUmL−1 was observed in all matrices, demonstrating the suitability of this device for field assays.

Hand-Held Optical Devices for Breast Cancer: Spectroscopy and 3-D Tomographic Imaging

Diffuse optical imaging (DOI) is a promising noninvasive and nonionizing method for breast imaging. Several research groups have developed hand-held-based optical imaging devices which are portable and patient-comfortable toward clinical translation of the technology. The different hand-held optical devices developed to date are reviewed herein with a focus on the clinical applications. The hand-held device developed at Florida International University is unique in its ability to perform 3-D tomography using DOI alone via self-coregistration facilities. Results demonstrate the ability of the device to perform 2-D imaging and 3-D tomography in human breast tissue.

P2.13 Image-Guided and Targeted Therapy Using Theranostic Nanoparticles for Personalized Cancer Treatment

ABSTRACT Highly heterogeneous cancer cells represent the major challenge in clinical oncology for the treatment of human cancers. Novel therapeutic approaches that enable the application of personalized therapy for cancer patients hold great promise for effective treatment while minimizing systemic toxicity. We have developed an integrated cancer image-therapy protocol that takes advantages of multifunctionality of theranostic nanoparticles and advanced molecular imaging methods for biomarker-targeted tumor imaging and drug delivery, MRI monitoring therapeutic response, and optical image-guided surgery. Multifunctional magnetic iron oxide nanoparticles (IONPs) developed by our group are targeted to epidermal growth factor receptor, Her-2/Neu, and urokinase plasminogen activator receptor, which are biomarkers highly expressed in many types of human cancers. These receptor-targeted IONPs have capacity to carry single or multiple therapeutic agents for drug delivery, near infrared fluorescence and spectroscopic optical imaging, and magnetic resonance imaging (MRI). They are also designed to overcome physical and intrinsic barriers that reduce efficiency of drug delivery and confer drug resistance in human cancers. We have shown specificity and sensitivity of optical and MR imaging using the nanoparticles as targeted molecular contrast agents in orthotopic human breast, pancreatic, and ovarian cancer xenograft models. The development of biomarker targeted MRI nanoparticle probes should allow determining the level of biomarker expression in tumors using a non-invasive imaging approach for selection of the appropriate patients for targeted therapy. Based on the targeted imaging nanoparticles, we further developed methods to encapsulate or conjugate chemotherapy drugs into the nanoparticles. Efficacy of targeted therapy and MRI-monitoring drug delivery and response after systemic delivery of the theranostic nanoparticles has been demonstrated in orthotopic human breast, pancreatic and ovarian cancer xenograft models in nude mice. Since drug resistant residual tumors contain nanoparticles that produce optical signals, we applied hand-held optical imaging devices for detection and removal of drug resistant tumor lesions in the surgical cavity to prevent local recurrence and distant metastasis. The ultimate goal of our research is to translate this biomarker targeted therapy and image-guided treatment and surgery protocol into clinical applications for personalized management of cancer patients. Download : Download full-size image Fig. 1 . An integrated therapy-imaging approach for personalized therapy and effective treatment of drug-resistant cancers

A handheld optical device for image-guided surgery

A handheld optical device for image-guided surgery

Handheld device for fast and non-contact optical measurement of protein films on surfaces

Thin films of bacteria, proteins and other biochemical substances are almost always found on surfaces exposed to the environment. Optical methods enable innovative tools for the study of such films. Residua of proteins exhibit fluorescence when excited in the UV. We present a specially designed handheld measuring device that can detect organic contamination levels down to 100 ng/cm² with measurement times shorter than a second. Using time-correlated spectroscopy methods the fluorescence detection of contamination levels on surfaces is possible even if the fluorescence spectra of contamination and base material overlap. The results presented in this paper show that a detection of contamination levels of bovine serum albumine (BSA) down to 100 ng/cm² is possible on non-fluorescent materials. A theoretical analysis shows the possibility to detect BSA levels down to less than 1 ng/cm² with the presented setup. Future development of handheld optical devices suitable for the detection or analysis of various compounds can be based on these results. A compact formalism is suggested that can be used to calculate the minimal concentration of a given organic contamination that can be detected with a certain measurement setup.