Label-Free Identification of Exosomes using Raman Spectroscopy and Machine Learning.

Exosomes, nano-sized extracellular vesicles (EVs) secreted from cells, carry various cargo molecules reflecting their cells of origin. As EV content, structure, and size are highly heterogeneous, their classification via cargo molecules by determining their origin is challenging. Here, a method is presented combining surface-enhanced Raman spectroscopy (SERS) with machine learning algorithms to employ the classification of EVs derived from five different cell lines to reveal their cellular origins. Using an artificial neural network algorithm, it is shown that the label-free Raman spectroscopy method's prediction ratio correlates with the ratio of HT-1080 exosomes in the mixture. This machine learning-assisted SERS method enables a new direction through label-free investigation of EV preparations by differentiating cancer cell-derived exosomes from those of healthy. This approach will potentially open up new avenues of research for early detection and monitoring of various diseases, including cancer.

Automated Image Analysis for Characterization of Circulating Tumor Cells and Clusters Sorted by Magnetic Levitation.

Magnetic levitation-based sorting technologies have revolutionized the detection and isolation of rare cells, including circulating tumor cells (CTCs) and circulating tumor cell clusters (CTCCs). Manual counting and quantification of these cells are prone to time-consuming processes, human error, and inter-observer variability, particularly challenging when heterogeneous cell types in 3D clusters are present. To overcome these challenges, we developed "Fastcount," an in-house MATLAB-based algorithm for precise, automated quantification and phenotypic characterization of CTCs and CTCCs, in both 2D and 3D. Fastcount is 120 times faster than manual counting and produces reliable results with a ±7.3% deviation compared to a trained laboratory technician. By analyzing 400 GB of fluorescence imaging data, we showed that Fastcount outperforms manual counting and commercial software when cells are aggregated in 3D or staining artifacts are present, delivering more accurate results. We further employed Fastcount for automated analysis of 3D image stacks obtained from CTCCs isolated from colorectal adenocarcinoma and renal cell carcinoma blood samples. Interestingly, we observed a highly heterogeneous spatial cellular composition within CTCCs, even among clusters from the same patient. Overall, Fastcount can be employed for various applications with lab-chip devices, such as CTC detection, CTCC analysis in 3D and cell detection in biosensors.

BIO-INSPIRED MAGNETIC BEADS FOR ISOLATION OF SPERM FROM HETEROGENOUS SAMPLES IN FORENSIC APPLICATIONS.

Rapid and efficient processing of sexual assault evidence will accelerate forensic investigation and decrease casework backlogs. The standardized protocols currently used in forensic laboratories require the continued innovation to handle the increasing number and complexity of samples being submitted to forensic labs. Here, we present a new technique leveraging the integration of a bio-inspired oligosaccharide (i.e., Sialyl-LewisX) with magnetic beads that provides a rapid, inexpensive, and easy-to-use strategy that can potentially be adapted with current differential extraction practice in forensics labs. This platform (i) selectively captures sperm; (ii) is sensitive within the forensic cut-off; (iii) provides a cost effective solution that can be automated with existing laboratory platforms; and (iv) handles small volumes of sample (∼200 µL). This strategy can rapidly isolate sperm within 25 minutes of total processing that will prepare the extracted sample for downstream forensic analysis and ultimately help accelerate forensic investigation and reduce casework backlogs.

Soft Ring-Shaped Cellu-Robots with Simultaneous Locomotion in Batches.

Untethered mini-robots can move single cells or aggregates to build complex constructs in confined spaces and may enable various biomedical applications such as regenerative repair in medicine and biosensing in bioengineering. However, a significant challenge is the ability to control multiple microrobots simultaneously in the same space to operate toward a common goal in a distributed operation. A locomotion strategy that can simultaneously guide the formation and operation of multiple robots in response to a common acoustic stimulus is developed. The scaffold-free cellu-robots comprise only highly packed cells and eliminate the influence of supportive materials, making them less cumbersome during locomotion. The ring shape of the cellu-robot contributes to anisotropic cellular interactions which induce radial cellular orientation. Under a single stimulus, several cellu-robots form predetermined complex structures such as bracelet-like ring-chains which transform into a single new living entity through cell-cell interactions, migration or cellular extensions between cellu-robots.

A confirmatory test for sperm in sexual assault samples using a microfluidic-integrated cell phone imaging system.

Rapid and efficient processing of sexual assault evidence to accelerate forensic investigation and decrease casework backlogs is urgently needed. Therefore, the standardized protocols currently used in forensic laboratories can benefit from continued innovation to handle the increasing number and complexity of samples being submitted to forensic labs. To our knowledge, there is currently no available rapid and portable forensic screening technology based on a confirmatory test for sperm identification in a sexual assault kit. Here, we present a novel forensic sample screening tool, i.e., a microchip integrated with a portable cell phone imaging platform that records and processes images for further investigation and storage. The platform (i) precisely and rapidly screens swab samples (<15 min after sample preparation on-chip); (ii) selectively captures sperm from mock sexual assault samples using a novel and previously published SLeX-based surface chemistry treatment (iii) separates non-sperm contents (epithelial cells and debris in this case) out of the channel by flow prior to imaging; (iv) captures cell phone images on a portable cellphone-integrated imaging platform, (v) quantitatively differentiates sperm cells from epithelial cells, using a morphology detection code that leverages Laplacian of Gaussian and Hough gradient transform methods; (vi) is sensitive within a forensic cut-off (>95% accuracy) compared to the manual counts; (vii) provides a cost-effective and timely solution to a problem which in the past has taken a great deal of time; and (viii) handles small volumes of sample (20 µL). This integration of the cellphone imaging platform and cell recognition algorithms with disposable microchips can be a new direction toward a direct visual test to screen and differentiate sperm from epithelial cell types in forensic samples for a crime laboratory scenario. With further development, this integrated platform could assist a sexual assault nurse examiner (SANE) in a hospital or sexual assault treatment center facility to flag sperm-containing samples prior to further downstream testing.

Levitating Cells to Sort the Fit and the Fat.

Density is a core material property and varies between different cell types, mainly based on differences in their lipid content. Sorting based on density enables various biomedical applications such as multi-omics in precision medicine and regenerative repair in medicine. However, a significant challenge is sorting cells of the same type based on density differences. Here, a new method for real-time monitoring and sorting of single cells based on their inherent levitation profiles driven by their lipid content is reported. As a model system, human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (CMs) from a patient with neutral lipid storage disease (NLSD) due to loss of function of adipose triglyceride lipase (ATGL) resulting in abnormal lipid storage in cardiac muscle are used. This levitation-based strategy detects subpopulations within ATGL-deficient hiPSC-CMs with heterogenous lipid content, equilibrating at different levitation heights due to small density differences. In addition, sorting of these differentially levitating subpopulations are monitored in real time. Using this approach, sorted healthy and diseased hiPSC-CMs maintain viability and function. Pixel-tracking technologies show differences in contraction between NLSD and healthy hiPSC-CMs. Overall, this is a unique approach to separate diseased cell populations based on their intracellular lipid content that cannot be achieved using traditional flow cytometry techniques.

Total Microfluidic chip for Multiplexed diagnostics (ToMMx).

Microfluidic technologies offer new platforms for biosensing in various clinical and point-of-care (POC) applications. Currently, at the clinical settings, the gold standard diagnostic platforms for multiplexed sensing are multi-step, time consuming, requiring expensive and bulky instruments with a constant need of electricity which makes them unsuitable for resource-limited or POC settings. These technologies are often limited by logistics, costly assays and regular maintenance. Although there have been several attempts to miniaturize these diagnostic platforms, they stand short of batch fabrication and they are dependent on complementary components such as syringe pumps. Here, we demonstrated the development and clinical testing of a disposable, multiplexed sensing device (ToMMx), which is a portable, high-throughput and user-friendly microfluidic platform. It was built with inexpensive plastic materials and operated manually without requiring electrical power and extensive training. We validated this platform in a small cohort of 50 clinical samples from patients with cardiovascular diseases and healthy controls. The platform is rapid and gives quantifiable results with high sensitivity, as low as 5.29 pg/mL, from only a small sample volume (4 µL). ToMMx platform was compared side-by-side with commercial ELISA kits where the total assay time is reduced 15-fold, from 5 h to 20 min. This technology platform is broadly applicable to various diseases with well-known biomarkers in diagnostics and monitoring, especially with potential future impact at the POC settings.