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[ASME ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference - Boston, Massachusetts, USA (Sunday 2 August 2015)] Volume 3: 17th International Conference on Advanced Vehicle Technologies; 12th International Conference on Design Education; 8th Frontiers in Biomedical Devices - Low-Cost Label-Free Bio-Detection System Using Double-Sided Grating Waveguide Couplers
摘要： Low-cost label-free bio-sensing systems have long been desired to enable rapid, sensitive, quantitative, and high-throughput biosensing and chemical applications. Here we present an optical bio-detection system consists of injection-molded biosensors based on double-sided grating waveguide couplers and an optical intensity-based detection platform for low-cost, real-time, and label-free bio-sensing. The biosensors were fabricated combining injection-molding and sputtering techniques, providing unique advantages of low-cost and reduced production time. A simple and cost-effective optical intensity-based detection system employing a low-cost light emitting diode and a simple photodetector is also developed to perform label-free bio-sensing. We demonstrate that a high refractive index resolution of 6.43 x 10^-5 RIU is achieved with this compact bio-sensing system, showing great promises for low-cost, real-time, label-free detection in bio-medical and chemical applications.
关键词： label-free bio-sensing,double-sided grating waveguide couplers,optical bio-detection system,optical intensity-based detection,injection-molded biosensors
更新于2025-09-09 09:28:46
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Label-free bacteria quantification in blood plasma by a bioprinted microarray based interferometric point-of-care device
摘要： Existing clinical methods for bacteria detection lack in speed, sensitivity and importantly in Point-of-Care (PoC) applicability. Thus, finding ways to push the sensitivity of clinical PoC biosensing technologies is crucial. Aiming that, we here report a portable PoC device based on Lens-free Interferometric Microscopy (LIM). The device employs high performance nanoplasmonics and custom bioprinted microarrays and is capable of direct label-free bacteria (E. coli) quantification. With only one-step sample handling we offer a sample?to?data turnaround time of 40 minutes. Our technology features detection sensitivity of a single bacterial cell both in buffer and diluted blood plasma and is intrinsically limited by the number of cells present in the detection volume. When employed in a hospital setting, the device has enabled accurate categorization of sepsis patients (infectious SIRS) from control groups (healthy individuals and non-infectious SIRS patients) without false positives/negatives. User-friendly on-site bacterial clinical diagnosis can thus become a reality.
关键词： microarray,label-free detection,plasma samples,nanoplasmonics,sepsis,bacteria
更新于2025-09-09 09:28:46
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Label-Free Digital Holo-tomographic Microscopy Reveals Virus-Induced Cytopathic Effects in Live Cells
摘要： Cytopathic effects (CPEs) are a hallmark of infections. CPEs are difficult to observe due to phototoxicity from classical light microscopy. We report distinct patterns of virus infections in live cells using digital holo-tomographic microscopy (DHTM). DHTM is label-free and records the phase shift of low-energy light passing through the specimen on a transparent surface with minimal perturbation. DHTM measures the refractive index (RI) and computes the refractive index gradient (RIG), unveiling optical heterogeneity in cells. We find that vaccinia virus (VACV), herpes simplex virus (HSV), and rhinovirus (RV) infections progressively and distinctly increased RIG. VACV infection, but not HSV and RV infections, induced oscillations of cell volume, while all three viruses altered cytoplasmic membrane dynamics and induced apoptotic features akin to those caused by the chemical compound staurosporine. In sum, we introduce DHTM for quantitative label-free microscopy in infection research and uncover virus type-specific changes and CPE in living cells with minimal interference.
关键词： tomography,virus infection,apoptosis,herpes simplex virus,live-cell microscopy,membrane blebbing,cell volume,refractive index,cell contraction,rhinovirus,label-free microscopy,vaccinia virus
更新于2025-09-09 09:28:46
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Micropatterning of Porous Silicon Bragg Reflectors With Poly(Ethylene Glycol) to Fabricate Cell Microarrays: Towards Single Cell Sensing
摘要： The work presented here describes the development of optical label-free biosensor based on PSi Bragg reflector to study heterogeneity in single cells. Photolithographic patterning of poly(ethylene glycol) hydrogel with photoinitiator was employed on RGD peptide-modified PSi to create micropatterns with cell adhesive and cell repellent areas and J774 macrophage cells were incubated to form cell microarrays and single cell arrays. Moreover, cells on the microarrays were lysed osmotically with Milli-Q? water and the infiltration of cell lysate into the porous matrix was monitored by measuring the red shift in the reflectivity. On average, the magnitude of red shift increased with the increase in the number of cells on the micropatterns. The red shift from the spots with single cells varied from spot to spot emphasizing the heterogeneous nature of the individual cells.
关键词： porous silicon (PSi),cell patterning,cell lysis,label-free biosensing,poly(ethylene glycol (PEG) hydrogel
更新于2025-09-04 15:30:14
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Label-Free Identification of Lymphocyte Subtypes Using Three-Dimensional Quantitative Phase Imaging and Machine Learning
摘要： We describe here a protocol for the label-free identification of lymphocyte subtypes using quantitative phase imaging and machine learning. Identification of lymphocyte subtypes is important for the study of immunology as well as diagnosis and treatment of various diseases. Currently, standard methods for classifying lymphocyte types rely on labeling specific membrane proteins via antigen-antibody reactions. However, these labeling techniques carry the potential risks of altering cellular functions. The protocol described here overcomes these challenges by exploiting intrinsic optical contrasts measured by 3D quantitative phase imaging and a machine learning algorithm. Measurement of 3D refractive index (RI) tomograms of lymphocytes provides quantitative information about 3D morphology and phenotypes of individual cells. The biophysical parameters extracted from the measured 3D RI tomograms are then quantitatively analyzed with a machine learning algorithm, enabling label-free identification of lymphocyte types at a single-cell level. We measure the 3D RI tomograms of B, CD4+ T, and CD8+ T lymphocytes and identified their cell types with over 80% accuracy. In this protocol, we describe the detailed steps for lymphocyte isolation, 3D quantitative phase imaging, and machine learning for identifying lymphocyte types.
关键词： lymphocyte identification,machine learning,holotomography,immune cell,immunology,Immunology and Infection,Quantitative phase imaging,optical diffraction tomography,holographic microscopy,label-free imaging
更新于2025-09-04 15:30:14
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Quantifying single-cell secretion in real time using resonant hyperspectral imaging
摘要： Cell communication is primarily regulated by secreted proteins, whose inhomogeneous secretion often indicates physiological disorder. Parallel monitoring of innate protein-secretion kinetics from individual cells is thus crucial to unravel systemic malfunctions. Here, we report a label-free, high-throughput method for parallel, in vitro, and real-time analysis of specific single-cell signaling using hyperspectral photonic crystal resonant technology. Heterogeneity in physiological thrombopoietin expression from individual HepG2 liver cells in response to platelet desialylation was quantified demonstrating how mapping real-time protein secretion can provide a simple, yet powerful approach for studying complex physiological systems regulating protein production at single-cell resolution.
关键词： single-cell analysis,photonic biosensing,photonic crystal,label-free
更新于2025-09-04 15:30:14
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Label-free characterization of exosome via surface enhanced Raman spectroscopy for the early detection of pancreatic Cancer
摘要： Pancreatic cancer is a highly lethal malignancy. Lack of early diagnostic markers makes timely detection of pancreatic cancer a highly challenging endeavor. Exosomes have emerged as information-rich cancer specific biomarkers. However, characterization of tumor-specific exosomes has been challenging. This study investigated the proof-of principal that exosomes could be used for the detection of pancreatic cancer. Label-free analysis of exosomes purified from normal and pancreatic cancer cell lines was performed using surface enhanced Raman Spectroscopy (SERS) and principal component differential function analysis (PC-DFA), to identify tumor-specific spectral signatures. This method differentiated exosomes originating from pancreatic cancer or normal pancreatic epithelial cell lines with 90% accuracy. The cell line trained PC-DFA algorithm was next applied to SERS spectra of serum-purified exosomes. This method exhibited up to 87% and 90% predictive accuracy for HC and EPC individual samples, respectively. Overall, our study identify utility of SERS spectral signature for deciphering exosomal surface signature.
关键词： surface enhanced Raman spectroscopy,liquid biopsy,Pancreatic cancer,exosome,label-free
更新于2025-09-04 15:30:14
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Motility-based label-free detection of parasites in bodily fluids using holographic speckle analysis and deep learning
摘要： Parasitic infections constitute a major global public health issue. Existing screening methods that are based on manual microscopic examination often struggle to provide sufficient volumetric throughput and sensitivity to facilitate early diagnosis. Here, we demonstrate a motility-based label-free computational imaging platform to rapidly detect motile parasites in optically dense bodily fluids by utilizing the locomotion of the parasites as a specific biomarker and endogenous contrast mechanism. Based on this principle, a cost-effective and mobile instrument, which rapidly screens ~3.2 mL of fluid sample in three dimensions, was built to automatically detect and count motile microorganisms using their holographic time-lapse speckle patterns. We demonstrate the capabilities of our platform by detecting trypanosomes, which are motile protozoan parasites, with various species that cause deadly diseases affecting millions of people worldwide. Using a holographic speckle analysis algorithm combined with deep learning-based classification, we demonstrate sensitive and label-free detection of trypanosomes within spiked whole blood and artificial cerebrospinal fluid (CSF) samples, achieving a limit of detection of ten trypanosomes per mL of whole blood (~five-fold better than the current state-of-the-art parasitological method) and three trypanosomes per mL of CSF. We further demonstrate that this platform can be applied to detect other motile parasites by imaging Trichomonas vaginalis, the causative agent of trichomoniasis, which affects 275 million people worldwide. With its cost-effective, portable design and rapid screening time, this unique platform has the potential to be applied for sensitive and timely diagnosis of neglected tropical diseases caused by motile parasites and other parasitic infections in resource-limited regions.
关键词： parasitic infections,holographic speckle analysis,trypanosomes,resource-limited settings,deep learning,Trichomonas vaginalis,label-free imaging,motility-based detection
更新于2025-09-04 15:30:14
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Intraoperative visualization of the tumor microenvironment and quantification of extracellular vesicles by label-free nonlinear imaging
摘要： Characterization of the tumor microenvironment, including extracellular vesicles (EVs), is important for understanding cancer progression. EV studies have traditionally been performed on dissociated cells, lacking spatial information. Since the distribution of EVs in the tumor microenvironment is associated with cellular function, there is a strong need for visualizing EVs in freshly resected tissues. We intraoperatively imaged untreated human breast tissues using a custom nonlinear imaging system. Label-free optical contrasts of the tissue, correlated with histological findings, enabled point-of-procedure characterization of the tumor microenvironment. EV densities from 29 patients with breast cancer were found to increase with higher histologic grade and shorter tumor-to-margin distance and were significantly higher than those from 7 cancer-free patients undergoing breast reduction surgery. Acquisition and interpretation of these intraoperative images not only provide real-time visualization of the tumor microenvironment but also offer the potential to use EVs as a label-free biomarker for cancer diagnosis and prognosis.
关键词： extracellular vesicles,label-free nonlinear imaging,breast cancer,intraoperative imaging,tumor microenvironment
更新于2025-09-04 15:30:14
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Fabrication of Immunosensor Based on Au-silica Nanocomposite for Neuron-specific Enolase Detection
摘要： Neuron-specific enolase (NSE), a type of neuroendocrine molecule, is a putative serum marker for small-cell lung carcinoma. This work addressed the fabrication of a signal-enhanced, label-free, electrochemical immunosensor based on Au nanoparticle/mesoporous silica nanoparticles (Au-MSNs) for NSE determination. Because of the large number of active sites provided by the Au-SiO2 sensor, the modified immunosensor has a significantly enhanced sensitivity. Furthermore, during quantitative NSE detection, the sensor has a desirable linear relationship with the concentration (0.1-2000 ng/mL) and a detection limit of 0.05 ng/mL.
关键词： Neuron-specific enolase (NSE),Label-free,Electrochemical immunosensors,Silica immunosensor,Signal-enhanced
更新于2025-09-04 15:30:14