Oblique injection depth correction by two parallel OCT sensors guided handheld SMART injector

We present a SMART injector with two parallel common-path optical coherence tomography fibers to enable angle measurements and injection depth corrections for oblique subretinal injection. The two optical fibers are attached to opposite sides of a 33 G needle with known offsets and designed to pass through a 23 G trocar that has an inner diameter of 0.65 mm. By attaching a SMART system to a rotational stage, the measured angles are calibrated for minimal error from reference angles. A commercial eye model was used to evaluate the control performance, and injection experiments were performed on a phantom made of agarose gel and a porcine eye. © 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.1

Idiopathic Pulmonary Fibrosis Causes Imbalance in Pulmonary Cell Viability in Response to Ionizing Radiation

This research was supported by the Undergraduate Research Opportunities Program (UROP)

Ionizing Radiation Increases Type I Collagen Matrix Production and May Contribute to Pulmonary Fibrosis

Faculty advisor: Richard NhoThis research was supported by the Undergraduate Research Opportunities Program (UROP)

Handheld motorized injection system with fiber-optic distance sensors and adaptive time-delay controller

AbstractDuring the last decade, many ophthalmic therapeutic drugs have been clinically approved, and intraocular injection has been a common surgical intervention. Injecting drugs directly into the subretinal space is crucial to treat retinal complications effectively. Here, we report a handheld microinjector with two fiber-optic distance sensors and time-delay control (TDC) to mitigate nonlinear disturbances during the injection task. The conventional method exhibited a cosine error of approximately 77 μm at an angle of 45°, whereas our proposed needle reduced measurement errors to ∼6 μm. Also, TDC-based position regulation is designed to adaptively apply motor inputs by estimating disturbances during the handheld task and achieving fast system responses with minor control errors. Phantom studies show a maximum reduction of 26.5% in root-mean-square error (RMSE) compared to the existing approach. Moreover, ex-vivo experiments demonstrated superior and robust injection performance, resulting in an injection RMSE of 10.3 μm

Modified Phase-Offset-Driven Lissajous Scanning Endomicroscopy With a Polyimide-Film-Based Frequency Separator

This article presents a Lissajous scanning confocal endomicroscopy comprising an easily manufacturable thin polyimide (PI) film and modified phase-offset-driven scanning. The Lissajous scanning confocal probe has a piezoelectric tube actuator and the PI film-attached fiber cantilever designed to resonate with the lever mechanism. Data from a finite element analysis and experiments are used to optimize the dimensions of the PI film, which produces a frequency separation and field of view of 195Hz and 180μm×180μm , respectively, at driving voltages less than 30Vpp . The best combination of decimal frequencies with optimized driving phase offsets is determined to achieve a scanning density (SD) exceeding 80% consistently with an imaging speed of 8Hz . By analyzing the Lissajous patterns at different decimal frequency combinations via time-delay analysis, it is possible to find more diverse combinations that meet the SD criterion. When the scanning patterns deviate from the desired paths, the proposed modified phase-offset-driven method is applied to maintain the best scanning pattern. The USAF 1951 test pattern, several plants, and rat gastrointestinal tract were imaged successfully using the confocal endomicroscopic system with the PI film and modified phase-offset-driven scanning. © Authors, CCBY - IEEE is not the copyright holder of this material.TRU

Advanced Therapeutic Strategies for Chronic Lung Disease Using Nanoparticle-Based Drug Delivery

Chronic lung diseases include a variety of obstinate and fatal diseases, including asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), idiopathic pulmonary fibrosis (IPF), and lung cancers. Pharmacotherapy is important for the treatment of chronic lung diseases, and current progress in nanoparticles offers great potential as an advanced strategy for drug delivery. Based on their biophysical properties, nanoparticles have shown improved pharmacokinetics of therapeutics and controlled drug delivery, gaining great attention. Herein, we will review the nanoparticle-based drug delivery system for the treatment of chronic lung diseases. Various types of nanoparticles will be introduced, and recent innovative efforts to utilize the nanoparticles as novel drug carriers for the effective treatment of chronic lung diseases will also be discussed

Enhanced location tracking in sensor fusion-assisted virtual reality micro-manipulation environments

Virtual reality (VR) technology plays a significant role in many biomedical applications. These VR scenarios increase the valuable experience of tasks requiring great accuracy with human subjects. Unfortunately, commercial VR controllers have large positioning errors in a micro-manipulation task. Here, we propose a VR-based framework along with a sensor fusion algorithm to improve the microposition tracking performance of a microsurgical tool. To the best of our knowledge, this is the first application of Kalman filter in a millimeter scale VR environment, by using the position data between the VR controller and an inertial measuring device. This study builds and tests two cases: (1) without sensor fusion tracking and (2) location tracking with active sensor fusion. The static and dynamic experiments demonstrate that the Kalman filter can provide greater precision during micro-manipulation in small scale VR scenarios

Exploring the Potential of Modifying Visual Stimuli in Virtual Reality to Reduce Hand Tremor in Micromanipulation Tasks

Involuntary hand tremor has been a serious challenge in micromanipulation tasks and thus draws a significant amount of attention from related fields. To minimize the effect of the hand tremor, a variety of mechanically assistive solutions have been proposed. However, approaches increasing human awareness of their own hand tremor have not been extensively studied. In this paper, a head mount display based virtual reality (VR) system to increase human self-awareness of hand tremor is proposed. It shows a user a virtual image of a handheld device with emphasized hand tremor information. Provided with this emphasized tremor information, we hypothesize that subjects will control their hand tremor more effectively. Two methods of emphasizing hand tremor information are demonstrated: (1) direct amplification of tremor and (2) magnification of virtual object, in comparison to the controlled condition without emphasized tremor information. A human-subject study with twelve trials was conducted, with four healthy participants who performed a task of holding a handheld gripper device in a specific direction. The results showed that the proposed methods achieved a reduced level of hand tremor compared with the control condition. © 2017 Current Optics and Photonics.1

Lissajous confocal fluorescent endomicroscopy with a lever mechanism and a frequency separation by an asymmetric polymer tube

We present a confocal fluorescent endomicroscopic system with a Lissajous scan using an asymmetric polymer tube and piezoelectric (PZT) tube actuator. The fiber cantilever’s scanning part is often inside the PZT tube actuator to reduce the scanner’s rigid length and enhance the beam deflection via a lever mechanism. Here, the mathematical model of the PZT tube actuator-based lever mechanism is first proposed by considering the piezoelectric parameters of the actuator and Euler-Bernoulli beam deflection, showing a good agreement with experimental data. In addition, an elliptical polymer tube is used to divide the resonant frequencies of the fiber cantilever, allowing enough scanning amplitudes and alleviating the inherent cross-coupling issue of a PZT tube actuator. The design optimization is performed by selecting the optimal lever length and the shape of the PFA tube. The implemented endomicroscopic probe could successfully acquire imaging results from both a lens-cleaning tissue and an ex-vivo mouse colon. © 2023 The Author(s). Published with license by Taylor & Francis Group, LLC.TRU