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Objective: To conduct a proof-of-concept study of the detection of two synthetic models of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using polarimetric imaging., Approach: Two SARS-CoV-2 models were prepared as engineered lentiviruses pseudotyped with the G protein of the vesicular stomatitis virus, and with the characteristic Spike protein of SARS-CoV-2. Samples were prepared in two biofluids (saline solution and artificial saliva), in four concentrations, and deposited as 5-µL droplets on a supporting plate. The angles of maximal degree of linear polarization (DLP) of light diffusely scattered from dry residues were determined using Mueller polarimetry from87 samples at 405 nm and 514 nm. A polarimetric camera was used for imaging several samples under 380-420 nm illumination at angles similar to those of maximal DLP. Per-pixel image analysis included quantification and combination of polarization feature descriptors in 475 samples., Main Results: The angles (from sample surface) of maximal DLP were 3° for 405 nm and 6° for 514 nm. Similar viral particles that differed only in the characteristic spike protein of the SARS-CoV-2, their corresponding negative controls, fluids, and the sample holder were discerned at 10-degree and 15-degree configurations., Significance: Polarimetric imaging in the visible spectrum may help improve fast, non-contact detection and identification of viral particles, and/or other microbes such as tuberculosis, in multiple dry fluid samples simultaneously, particularly when combined with other imaging modalities. Further analysis including realistic concentrations of real SARS-CoV-2 viral particles in relevant human fluids is required. Polarimetric imaging under visible light may contribute to a fast, cost-effective screening of SARS-CoV-2 and other pathogens when combined with other imaging modalities., Competing Interests: Emilio Gomez-Gonzalez reports financial support was provided by Spanish Ministry of Science and Innovation, Institute of Health ‘Carlos III’. Emilio Gomez-Gonzalez reports financial support was provided by Spanish Ministry of Science and Innovation and ERDF. Francisco Jose Garcia-Cozar reports financial support was provided by Spanish Ministry of Science and Innovation, Institute of Health ‘Carlos III’. Alejandro Barriga-Rivera reports financial support was provided by Spanish Ministry of Science and Innovation and ERDF. Olga Muñoz reports financial support was provided by Center of Excellence ‘Severo Ochoa’. Juan Carlos Gomez-Martin reports financial support was provided by Center of Excellence ‘Severo Ochoa’. Jose Luis Ramos reports financial support was provided by Center of Excellence ‘Severo Ochoa’. Olga Muñoz reports financial support was provided by Spanish Ministry of Science and Innovation (LEONIDAS Grant). Juan Carlos Gomez-Martin reports financial support was provided by Spanish Ministry of Science and Innovation (LEONIDAS Grant). Jose Luis Ramos reports financial support was provided by Spanish Ministry of Science and Innovation (LEONIDAS Grant). Emilio Gomez-Gonzalez has patent Apparatus and method for the optical detection of pathogens at a distance pending to Universidad de Sevilla and Andalusian Health Service. Alejandro Barriga-Rivera has patent Apparatus and method for the optical detection of pathogens at a distance pending to Universidad de Sevilla and Andalusian Health Service. Javier Marquez-Rivas has patent Apparatus and method for the optical detection of pathogens at a distance pending to Universidad de Sevilla and Andalusian Health Service. One coauthor serves as Handling Associate Editor for the Journal of Quantitative Spectroscopy & Radiative Transfer - Olga Muñoz, (© 2023 The Author(s).)

Effective testing is essential to control the coronavirus disease 2019 (COVID-19) transmission. Here we report a-proof-of-concept study on hyperspectral image analysis in the visible and near-infrared range for primary screening at the point-of-care of SARS-CoV-2. We apply spectral feature descriptors, partial least square-discriminant analysis, and artificial intelligence to extract information from optical diffuse reflectance measurements from 5 µL fluid samples at pixel, droplet, and patient levels. We discern preparations of engineered lentiviral particles pseudotyped with the spike protein of the SARS-CoV-2 from those with the G protein of the vesicular stomatitis virus in saline solution and artificial saliva. We report a quantitative analysis of 72 samples of nasopharyngeal exudate in a range of SARS-CoV-2 viral loads, and a descriptive study of another 32 fresh human saliva samples. Sensitivity for classification of exudates was 100% with peak specificity of 87.5% for discernment from PCR-negative but symptomatic cases. Proposed technology is reagent-free, fast, and scalable, and could substantially reduce the number of molecular tests currently required for COVID-19 mass screening strategies even in resource-limited settings., (© 2022. The Author(s).)

Spinal cord injury (SCI) is a devastating condition of the central nervous system that strongly reduces the patient's quality of life and has large financial costs for the healthcare system. Cell therapy has shown considerable therapeutic potential for SCI treatment in different animal models. Although many different cell types have been investigated with the goal of promoting repair and recovery from injury, stem cells appear to be the most promising. Here, we review the experimental approaches that have been carried out with pluripotent stem cells, a cell type that, due to its inherent plasticity, self-renewal, and differentiation potential, represents an attractive source for the development of new cell therapies for SCI. We will focus on several key observations that illustrate the potential of cell therapy for SCI, and we will attempt to draw some conclusions from the studies performed to date.

Neural stem cells represent an attractive tool for the development of regenerative therapies and are being tested in clinical trials for several neurological disorders. Human neural stem cells can be isolated from the central nervous system or can be derived in vitro from pluripotent stem cells. Embryonic sources are ethically controversial and other sources are less well characterized and/or inefficient. Recently, isolation of NSC from the cerebrospinal fluid of patients with spina bifida and with intracerebroventricular hemorrhage has been reported. Direct reprogramming may become another alternative if genetic and phenotypic stability of the reprogrammed cells is ensured. Here, we discuss the advantages and disadvantages of available sources of neural stem cells for the production of cell-based therapies for clinical applications. We review available safety and efficacy clinical data and discuss scalability and quality control considerations for manufacturing clinical grade cell products for successful clinical application.

Optical spectroscopic techniques have been commonly used to detect the presence of biofilm-forming pathogens (bacteria and fungi) in the agro-food industry. Recently, near-infrared (NIR) spectroscopy revealed that it is also possible to detect the presence of viruses in animal and vegetal tissues. Here we report a platform based on visible and NIR (VNIR) hyperspectral imaging for non-contact, reagent free detection and quantification of laboratory-engineered viral particles in fluid samples (liquid droplets and dry residue) using both partial least square-discriminant analysis and artificial feed-forward neural networks. The detection was successfully achieved in preparations of phosphate buffered solution and artificial saliva, with an equivalent pixel volume of 4 nL and lowest concentration of 800 TU·[Formula: see text]L -1 . This method constitutes an innovative approach that could be potentially used at point of care for rapid mass screening of viral infectious diseases and monitoring of the SARS-CoV-2 pandemic., (© 2021. The Author(s).)