The sudden outbreak of the COVID-19 pandemic led to a huge concern globally because of the astounding increase in mortality rates worldwide. The medical imaging computed tomography technique, whole-genome sequencing, and electron microscopy are the methods generally used for the screening and identification of the SARS-CoV-2 virus. The main aim of this review is to emphasize the capabilities of various optical techniques to facilitate not only the timely and effective diagnosis of the virus but also to apply its potential toward therapy in the field of virology. This review paper categorizes the potential optical biosensors into the three main categories, spectroscopic-, nanomaterial-, and interferometry-based approaches, used for detecting various types of viruses, including SARS-CoV-2. Various classifications of spectroscopic techniques such as Raman spectroscopy, near-infrared spectroscopy, and fluorescence spectroscopy are discussed in the first part. The second aspect highlights advances related to nanomaterial-based optical biosensors, while the third part describes various optical interferometric biosensors used for the detection of viruses. The tremendous progress made by lab-on-a-chip technology in conjunction with smartphones for improving the point-of-care and portability features of the optical biosensors is also discussed. Finally, the review discusses the emergence of artificial intelligence and its applications in the field of bio-photonics and medical imaging for the diagnosis of COVID-19. The review concludes by providing insights into the future perspectives of optical techniques in the effective diagnosis of viruses.

3D cell spheroids have become crucial in vitro models for biomedical research, yet maintaining their growth and viability remains challenging due to diffusion limitations. We developed a versatile microfluidic modular device with a reconfigurable channel design that is customizable by altering the channel configuration in the adhesive layer. The resealable adhesive layer also enables open access to the wells for loading cells, continuous perfusion after closing, and facile retrieval of spheroids for downstream analysis and imaging after culturing. We evaluated three channel configurations using Mouse Embryonic Fibroblasts (MEFs), human induced Pluripotent Stem Cells (hiPSCs), and MDA-MB-231 breast cancer cells. The device significantly improved spheroid growth in MEFs and hiPSCs, increasing up to 139.9% over controls in 14 days. In contrast, MDA-MB-231 spheroids exhibited slower growth, highlighting the need for balancing nutrient delivery with autocrine factor retention. Sphericity was maintained in MEF and MDA-MB-231 spheroids, while hiPSC spheroids experienced budding. In situ optical coherence tomography (OCT) provided noninvasive 3D viability assessments of the spheroids. Our findings demonstrate that this modular microfluidic device, combined with OCT analysis, offers a powerful platform for advancing spheroid culture techniques and opens up new opportunities in applications such as drug testing, studying spheroid–spheroid interactions, and collecting spheroid secretions.

Human body comprises of different internal and external biological components. Human organs tend to fail due to continuous or sudden stress which leads to deterioration, failure, and dislocation. The choice of selection and fabrication of materials for tissue engineering play a key role in terms of suitability, sensitivity, and functioning with other organs as a replacement for failed organs. The progressive improvement of the additive manufacturing (AM) approach in healthcare made it possible to print multi-material and customized complex/intricate geometries in a layer-by-layer fashion. The customized or patient-specific implant fabrication can be easily produced with a high success rate due to the development of AM technologies with tailorable properties. The structural behavior of 3D printed biomaterials is a crucial factor in tissue engineering as they affect the functionality of the implants. Various techniques have been developed in appraising the important features and the effects of the subsequent design of the biomaterial implants. The behavior of the AM built biomaterial implants can be understood visually by an imaging system with a high spatial and spectral resolution. This review intends to present an overview of various biomaterials used in implants, followed by a detailed description of optical 3D printing procedures and evaluation of the performance of 3D printed biomaterials using optical characterization.

The proposed technique based on frequency domain dual wavelength low coherence interferometry (FD-DWLCI) is demonstrated for sensing glucose in ex-vivo human gingival tissue, with preliminary studies performed on solid bilayer gingival tissue phantom and saline. A broad band supercontinuum source filtered using bandpass filters with centre wavelengths at 1300 nm, 1580 nm (corresponding to the first overtone region) and 2100 nm (corresponding to the combination band of glucose) was employed for the studies. Enhanced glucose resolutions of 11 mg/dl and 15 mg/dl were estimated for the ratio of relative reflectivity of wavelengths 2100 nm/1300 nm, in the gingival tissue phantom and ex-vivo human gingival tissue, respectively.