We developed a low-cost dual-modality high-resolution microendoscope, which implemented fluorescence imaging and darkfield reflectance imaging to characterize nuclear atypia and dysregulated angiogenesis for in vivo cancer detection. Cell nuclei and microvasculature located at different depths in tissue epithelium were visualized in high spatial resolution by using a compact fiber-based imaging probe with adjustable imaging depth.

We developed a novel deep-learning based algorithm for a mobile Detection of Oral Cancer (mDOC) platform that captures white light and auto-fluorescence images of the oral cavity. The algorithm first segments images and subsequently identifies suspicious lesions in need of further review by an expert clinician. Preliminary results show a dice score accuracy between ground truth annotated and the network produced segmentation to be higher than 0.9 for the network architectures we tested. This fully automated pipeline enables a data-driven approach with the potential to aid faster diagnosis in the clinic and earlier detection of oral lesions that can ultimately improve patient outcomes.

A novel OCT otoscope device is needed for measuring thickness changes of tympanic membrane, a structure that separates outer and middle ear. While the traditional otoscope imaging can only obtain a monocular view, the new otoscope is aimed at obtaining depth perception. This information will be crucial to early detect abnormal ear condition and prevent hearing loss (one third of older adults encounter it). Planar waveguide array structure, presented here, is designed for snapshot imaging spectrometer and full field optical OCT system. 2-photon polymerization (2PP) three dimensional (3D) printing is used to fabricate the structure. The benefits of using 2PP 3D printing include high degree of freedom in design, short manufacture time, and lower cost.

Accurate guidance of the epidural needle is important for ensuring the safety and efficacy of epidural anesthesia. Within this study, we proposed an endoscopic system built on polarization-sensitive optical coherence tomography (PS-OCT). To evaluate its viability, we performed experiments on ex-vivo human epidural specimens. Throughout the experimental process, we captured and analyzed various layers of spinal tissue that the epidural needle goes through during the surgery, including subcutaneous fat, supraspinous ligament, interspinous ligament, ligamentum flavum, epidural space, dura, and the spinal cord. Each of these tissue layers had distinctive OCT imaging patterns. Furthermore, we employed deep learning techniques for automated tissue recognition.

Monitoring dynamic activity of biochemical pathways is an essential, but challenging, step for diagnosing, treating, and understanding human pathologies. Transient absorption is a resonant two-photon optical imaging technique capable of probing multiple molecular-specific properties, such as ground state recovery time, absorption spectra, and transient absorption spectra, all with high resolution. Previously, photoacoustic based transient absorption imaging approaches have demonstrated the ability to probe ground state recovery time of biomolecules and provide spatial contrast on par with confocal microscopy. A fundamental challenge of these approaches relied on overlapping the focus of an ultrasound transducer with the optical focus for image detection, making the technique challenging to perform in vitro or in vivo. Here, we present non-contact methods for detecting transient absorption via the photoacoustic effect. These methods not only circumvent the need for ultrasound transducers but also enable integration with existing fluorescence imaging techniques.

The crystalline lens plays an important role in focusing light on the retina by a process called accommodation. Accommodation is inherently biomechanical as it involves reshaping the lens to adjust its optical power. Hence, assessing the biomechanical properties of the crystalline lens will improve our understanding of accommodation. Lens viscoelasticity changes are correlated to various eye conditions, such as cataract and presbyopia. Optical coherence elastography (OCE) is an established technique to quantify the mechanical properties of biological tissues and is particularly well-suited for characterizing the lens. Here, we utilize a non-contact OCE method utilizing air-coupled ultrasound excitation to quantify the stiffness of ex-vivo porcine lenses with and without the capsule. Phase-sensitive optical coherence tomography imaging was used for tracking mechanical wave propagation. The results show the lenticular stiffness significantly decreased after removal of the capsule, and that OCE has the potential to be used for in vivo investigations of lenticular mechanical properties.

Fiber lasers have transformed microscopy with their robustness and portability. Fiber laser-based stimulated Raman scattering (SRS) offers label-free chemical imaging but faces challenges like noise and high light collection requirements. To overcome these, we introduce stimulated Raman photothermal (SRP) microscopy with fiber lasers. SRP detects thermal effects induced by SRS, reducing sensitivity to laser noise and eliminating balance detection needs. Our setup allows light collection through a low NA air condenser, simplifying operation for non-experts. SRP demonstrates superior sensitivity, particularly in media with high thermos-optic coefficients, outperforming fiber laser-based SRS. We showcase SRP's efficacy in imaging biological samples, promising enhanced sensitivity, resolution, and user-friendliness. This innovation signifies a significant step forward in biological microscopy, offering potential for widespread adoption and groundbreaking discoveries in vibrational imaging.

Deep-tissue chemical imaging is essential for many biomedical applications. Here, we present a shortwave infrared photothermal (SWIP) microscope for millimeter-deep vibrational imaging with micron lateral resolution. By pumping the overtone transition of carbon-hydrogen bonds and probing the subsequent photothermal lens with shortwave infrared light, SWIP can obtain chemical contrast from one-micron polymer particles located at 800-μm depth in a highly scattering phantom. We demonstrated that SWIP can resolve intracellular lipids across an intact tumor spheroid and the layered structure in thick liver, skin, brain, and breast tissues. SWIP microscopy fills a gap in vibrational imaging with sub-cellular resolution and millimeter-level penetration, which heralds broad potential for life science and clinical applications.

Point-of-care depth resolved 3D imaging of the tympanic membrane and middle ear with OCT, combined with quantitative image analysis, could improve the diagnosis and management of patients in the clinical setting. We imaged the TMs and MEs of 55 patients in a neurotology clinic, using a custom-built hand-held OCT (HHOCT) device. Patients with a diagnosis of TM retraction pockets, perforations, cholesteatomas, and postoperative states were included in this study. Healthy volunteers were also imaged to provide a baseline for quantitative metrics. Images were post processed to perform segmentation of the TM and create thickness maps of the TM, derive mean TM thickness values, and conduct ear symmetry analysis. The normal mean TM thickness was found to be significantly different from every other condition explored. Ear symmetry of healthy subjects was found to be 80% between left and right ears. Quantitative metrics derived from OCT images can be used to characterize TM pathologies and potentially aid in diagnosis and management.

Prothrombin, or factor II, is vital in blood coagulation, transforming into active thrombin. The prothrombin time test (PTT) measures blood clotting time, crucial for heart disease patients on anticoagulants. Our study introduces a novel approach using refractive index to measure prothrombin time, validated through experimental outcomes. This method leverages light refraction principles, offering rapid results, simplicity, and point-of-care potential. Testing with clinical samples showed strong correlation with traditional PTT methods. Developing a point-of-care device for prothrombin time measurement promises to enhance patient care by enabling real-time monitoring of clotting efficiency, allowing timely adjustments to anticoagulant therapy, thus reducing risks of bleeding or thrombosis. The simplicity and accessibility of this method can revolutionize anticoagulant management, especially in resource-limited settings.

Significant challenges such as a high proportion of indeterminate results, inadequate sampling, and false positives remain prevalent in the diagnosis of thyroid cancer when using fine needle aspiration biopsy or core needle biopsy. Second harmonic generation (SHG) imaging is a label-free, nonlinear optical imaging method that selectively uses fibrillar collagen arrangement to provide endogenous contrast. We investigated applications of SHG-specific feature extraction methods such as anisotropy, and more broadly applied gray-level co-occurrence matrices to generate quantitative metrics that describe either the structural or physical properties of the imaged thyroid samples. The features differed significantly between thyroid cancer and normal thyroid samples, thus independently possessing the capability to differentiate between cancerous and normal thyroid tissue.

NanoString GeoMX Digital Spatial Profiling (DSP) is an emerging optical technology for spatial multi-omics. DSP utilizes probes attached to UV-photocleavable, fluorescent oligonucleotide barcodes indicating target identity and location. These barcodes are counted to quantify gene expression. This high-throughput, single-cell resolution tool exemplifies how optics can elucidate disease mechanisms. Our study employed DSP to understand T-DXd resistance in metastatic breast cancer (mBC). T-DXd is an antibody-drug conjugate that is standard of care in mBC. Patients have few options if T-DXd fails; uncovering resistance mechanisms is crucial for developing life-saving therapies. We used GeoMX DSP to investigate tumor-immune interactions in T-DXd responsive and resistant patient samples. We captured spatially diverse tumor-dense and tumor-sparse regions of interest for proteomics analysis. We found that local stromal remodeling and decreased killer T-cell infiltration are T-DXd resistance characteristics. These results show promise for helping T-DXd resistant-patients and highlight the importance of optical imaging in drug discovery.