Rapid detection of vaccinia virus using biofunctionalized fiber-optic ball-tip biosensors

In this work, we present the development and biofunctionalization of a fiber-optic ball-resonator biosensor for the real-time detection of vaccinia poxvirus. We fabricated several ball-tip resonators, functionalized through a silanization process to immobilize two bioreceptors: the monoclonal anti-L1R antibody targeting the L1R protein, and the polyclonal rabbit serum antibodies targeting the whole vaccinia virus (VV) pathogen. Experimental measurements were carried out to detect VV in concentrations from 103 to 108 plaque-forming units (PFU), with a limit of detection of around 1.7-4.3 × 103 PFU and a log-quadratic pattern, with a response up to 5 × 10-4 RIU (refractive index units). The specificity was assessed against herpes simplex virus, used as a non-specific control, with the best results obtained with anti-L1R monoclonal antibodies, and through the detection of vaccinia virus/herpes simplex-1 combination. The obtained results provide a real-time viral recognition with a label-free sensing platform, having rapid response and ease of manufacturing, and paving the road to the seamless detection of poxviruses affecting different human and animal species using optical fibers.

A L-glutamine binding protein modified MNM structured optical fiber biosensor based on surface plasmon resonance sensing for detection of L-glutamine metabolism in vitro embryo culture

A surface plasmon resonance (SPR) optical fiber sensor with multimode-coreless-multimode (MNM) structure was developed, which modified by L-glutamine-binding protein (QBP) for detection of L-glutamine (Gln). The QBP was immobilized on the surface of gold films by chemical cross-linking and exhibited a binding affinity for L-glutamine. The conformation of QBP can be changed from the "open" to the "closed", which led to a red-shift of the SPR peak when QBP bounded to L-glutamine. There was a good linear correlation between is a dependence of the SPR peak on and the concentration of L-glutamine concentration in the range 10-100 μM, with a sensitivity of 10.797nm/log10[Gln] for L-glutamine in the in vitro embryo culture (IVC) medium environment, and the limit of detection (LOD) is 1.187 μM. This QBP-modified MNM structure optical fiber SPR sensor provides a new idea for the developmental potential assessment of embryos in the process of in vitro embryo culture.

Sensitivity of the amide I band to matrix manipulation in bone: a Raman micro-spectroscopy and spatially offset Raman spectroscopy study

The fracture resistance of bone arises from the hierarchical arrangement of minerals, collagen fibrils (i.e., cross-linked triple helices of α1 and α2 collagen I chains), non-collagenous proteins, and water. Raman spectroscopy (RS) is not only sensitive to the relative fractions of these constituents, but also to the secondary structure of bone proteins. To assess the ability of RS to detect differences in the protein structure, we quantified the effect of sequentially autoclaving (AC) human cortical bone at 100 °C (∼34.47 kPa) and then at 120 °C (∼117.21 kPa) on the amide I band using a commercial Raman micro-spectroscopy (μRS) instrument and custom spatially offset RS (SORS) instrument in which rings of collection fiber optics are offset from the central excitation fiber optics within a hand-held, cylindrical probe. Being clinically viable, measurements by SORS involved collecting Raman spectra of cadaveric femur mid-shafts (5 male & 5 female donors) through layers of a tissue mimic. Otherwise, μRS and SORS measurements were acquired directly from each bone. AC-related changes in the helical status of collagen I were assessed using amide I sub-peak ratios (intensity, I, at ∼1670 cm-1 relative to intensities at ∼1610 cm-1 and ∼1640 cm-1). The autoclaving manipulation significantly decreased the selected amide I sub-peak ratios as well as shifted peaks at ∼1605 cm-1 (μRS), ∼1636 cm-1 (SORS) and ∼1667 cm-1 in both μRS and SORS. Compared to μRS, SORS detected more significant differences in the amide I sub-peak ratios when the fiber optic probe was directly applied to bone. SORS also detected AC-related decreases in I1670/I1610 and I1670/I1640 when spectra were acquired through layers of the tissue mimic with a thickness ≤2 mm by the 7 mm offset ring, but not with the 5 mm or 6 mm offset ring. Overall, the SORS instrument was more sensitive than the conventional μRS instrument to pressure- and temperature-related changes in the organic matrix that affect the fracture resistance of bone, but SORS analysis of the amide I band is limited to an overlying thickness layer of 2 mm.

Fiber-Optic-Based System for High-Resolution Monitoring of Stretch in Excised Tissues

Cardiovascular diseases cause a high number of deaths nowadays. To improve these statistics, new strategies to better understand the electrical and mechanical abnormalities underlying them are urgently required. This study focuses on the development of a sensor to measure tissue stretch in excised tissues, enabling improved knowledge of biomechanical properties and allowing greater control in real time. A system made of biocompatible materials is described, which is based on two cantilevered platforms that integrate an optical fiber inside them to quantify the amount of stretch the tissues are exposed to with a precision of μm. The operating principle of the sensor is based on the variation of the optical path with the movement of the platforms onto which the samples are fixed. The conducted tests highlight that this system, based on a simple topology and technology, is capable of achieving the desired purpose (a resolution of ∼1 μm), enabling the tissue to be bathed in any medium within the system.

Development of a two-beveled-fiber polarized fiber-optic Raman probe coupled with a ball lens for in vivo superficial epithelial Raman measurements in endoscopy

We report on the development of a two-beveled-fiber polarized (TBFP) fiber-optic Raman probe coupled with a ball lens for in vivo superficial epithelial Raman measurements in endoscopy. The two-beveled fibers positioned symmetrically along a ball lens, in synergy with paired parallel-polarized polarizers integrated between the fibers and the ball lens, maximize the Raman signal excitation and collection from the superficial epithelium where gastrointestinal (GI) precancer arises. Monte Carlo (MC) simulations and two-layer tissue phantom experiments show that the probe developed detects ∼90% of the Raman signal from the superficial epithelium. The suitability of the probe developed for rapid (<3 s) superficial epithelial Raman measurements is demonstrated on fresh swine esophagus, stomach, and colon tissues, followed by their differentiation with high accuracies (92.1% for esophagus [sensitivity: 89.3%, specificity: 93.2%], 94.1% for stomach [sensitivity: 86.2%, specificity: 97.2%], and 94.1% for colon [sensitivity: 93.2%, specificity: 94.7%]). The presented results suggest the great potential of the developed probe for enhancing in vivo superficial epithelial Raman measurements in endoscopy.

Development and in-vivo validation of a portable phosphorescence lifetime-based fiber-optic oxygen sensor

Oxygenation is a crucial indicator of tissue viability and function. Oxygen tension ([Formula: see text]), i.e. the amount of molecular oxygen present in the tissue is a direct result of supply (perfusion) and consumption. Thus, measurement of [Formula: see text] is an effective method to monitor tissue viability. However, tissue oximetry sensors commonly used in clinical practice instead rely on measuring oxygen saturation ([Formula: see text]), largely due to the lack of reliable, affordable [Formula: see text] sensing solutions. To address this issue we present a proof-of-concept design and validation of a low-cost, lifetime-based oxygen sensing fiber. The sensor consists of readily-available off-the shelf components such as a microcontroller, a light-emitting diode (LED), an avalanche photodiode (APD), a temperature sensor, as well as a bright in-house developed porphyrin molecule. The device was calibrated using a benchtop setup and evaluated in three in vivo animal models. Our findings show that the new device design in combination with the bright porphyrin has the potential to be a useful and accurate tool for measuring [Formula: see text] in tissue, while also highlighting some of the limitations and challenges of oxygen measurements in this context.

Real-time in vivo dose measurement using ruby-based fibre optic dosimetry during internal radiation therapy

In vivo dosimetry (IVD) in a commonly used liver cancer treatment of selective internal radiation therapy (SIRT) has been done based on the post-treatment image-based dosimetry approach. Real-time IVD is necessary to verify the dose delivery and detect errors during the treatment for better patient outcomes. This study aims to develop a fibre optic dosimeter (FOD) for in vivo real-time dose rate measurement during internal beta radiation therapy, e.g., SIRT. A ruby fibre optic probe was prepared and studied the radioluminescence (RL) characteristics, including its major challenge of stem effect arising from Cherenkov radiation and luminescence from the irradiated fibre. The stem signal was suppressed adequately using the stem removal technique of optical filtering, and only 2.3 ± 1.1% stem signal was contributed to the measured RL signal. A linear dose rate response was observed during the exposure of the ruby probe to varying dose rates using a 6 MeV electron beam and a positron-emitting radionuclide fluorine-18. The ruby exhibited a temporally non-constant RL signal, which increased the RL signal by 0.84 ± 0.29 counts/sec2 during the irradiation of the maximum dose rate used in this study of 9 Gy/min for 2 min. The ability of ruby FOD to measure the absolute dose rate with sufficient stem effect suppression and the linear RL dose rate response indicates its suitability for real-time IVD during internal beta radiation therapy. Future work will investigate the time-dependent RL characteristic of ruby and validate post-treatment image-based dosimetry using ruby-based FOD.

Fabry-Perot Interferometric Fiber-Optic Sensor for Rapid and Accurate Thrombus Detection

We present a fiber-optic sensor based on the principles of a Fabry-Perot interferometer (FPI), which promptly, sensitively, and precisely detects blood clot formation. This sensor has two types of sensor tips; the first was crafted by splicing a tapered fiber into a single-mode fiber (SMF), where fine-tuning was achieved by adjusting the tapered diameter and length. The second type is an ultra-compact blood FPI situated on the core of a single-mode fiber. The sensor performance was evaluated via clot-formation-indicating spectrum shifts induced by the varied quantities of a thrombin reagent introduced into the blood. The most remarkable spectral sensitivity of the micro-tip fiber type was approximately 7 nm/μL, with a power sensitivity of 4.1 dB/μL, obtained with a taper fiber diameter and length of 55 and 300 μm, respectively. For the SMF type, spectral sensitivity was observed to be 8.7 nm/μL, with an optical power sensitivity of 0.4 dB/μL. This pioneering fiber-optic thrombosis sensor has the potential for in situ applications, healthcare, medical monitoring, harsh environments, and chemical and biological sensing. The study underscores the scope of optical technology in thrombus detection, establishing a platform for future medical research and application.

Monitoring the Opening of Rapid Palatal Expansion (RPE) in a 3D-Printed Skull Model Using Fiber Optic F-P Sensors

We present a novel method for the online measurement of multi-point opening distances of midpalatal sutures during a rapid palatal expansion (RPE) using fiber optic Fabry-Perot (F-P) sensors. The sensor consists of an optical fiber with a cut flat end face and an optical reflector, which are implanted into the palatal base structure of an expander and is capable of measuring the precise distance between two optical reflective surfaces. As a demonstration, a 3D-printed skull model containing the maxilla and zygomaticomaxillary complex (ZMC) was produced and a miniscrew-assisted rapid palatal expander (MARPE) with two guide rods was used to generate the midpalatal suture expansion. The reflected spectrums of the sensors were used to dynamically extract cavity length information for full process monitoring of expansion. The dynamic opening of the midpalatal suture during the gradual activation of the expander was measured, and a displacement resolution of 2.5 μm was demonstrated. The angle of expansion was derived and the results suggested that the midpalatal suture was opened with a slight V-type expansion of 0.03 rad at the first loading and subsequently expanded in parallel. This finding might be useful for understanding the mechanical mechanisms that lead to different types of expansion. The use of a fiber optic sensor for mounting the rapid palatal expander facilitates biomechanical studies and experimental and clinical evaluation of the effects of RPE.

Label-Free DNA Detection Using Etched Tilted Bragg Fiber Grating-Based Biosensor

A label-free-based fiber optic biosensor based on etched tilted Bragg fiber grating (TFBG) is proposed and practically demonstrated. Conventional phase mask technic has been utilized to inscribe tilted fiber Bragg grating with a tilt angle of 10°, while the etching has been accomplished with hydrofluoric acid. A composite of polyethylenimine (PEI)/poly(acrylic acid) (PAA) has been thermally deposited on the etched TFBG, followed by immobilization of probe DNA (pDNA) on this deposited layer. The hybridization of pDNA with the complementary DNA (cDNA) has been monitored using wavelength-dependent interrogation. The reproducibility of the probes has been demonstrated by fabricating three identical probes and their response has been investigated for cDNA concentration ranging from 0 μM to 3 μM. The maximum sensitivity has been found to be 320 pm/μM, with the detection limit being 0.65 μM. Furthermore, the response of the probes towards non-cDNA has also been investigated in order to establish its specificity.

Enrichment and Selection of Particles through Parallel Induced-Charge Electro-osmotic Streaming for Detection of Low-Abundance Nanoparticles and Targeted Microalgae

Manipulation of micro- and nanoscale objects is an essential procedure in many detection and sensing applications, including disease diagnosis and environmental monitoring. Induced-charge electro-osmotic (ICEO) vortices present excellent advantages in the enrichment and selection of micro/nanoscale particles for downstream detection due to gentle conditions and contactless operation, but the application of this method is currently constrained by the throughput. Double-layer charging at the ends of bipolar electrodes can maintain a continuous flow of electric current in the fluidically isolated channels, which provides a feasible method to manipulate particles using parallel ICEO vortices, promoting throughput of particle manipulation without compromising efficiency and overcoming the complicated ohmic contact of electrodes. Encouraged by these, we put forward a novel method with parallel ICEO vortices to manipulate micro/nanoscale samples for downstream detection. First, we study the extension regulation of the low-frequency electric field and mediating effect of the open BPEs on the extended electric field and characterize electric equilibrium states of microparticles and their voltage dependence. Afterward, we leverage this method to enrich nanoparticles for detection of low-abundance nanoparticles with about 20- and 40-fold fluorescence intensities by integrating with a simple fiber-optic sensor. Furthermore, this technique is engineered for the selection of targeted microalgae to continuously detect their proliferation behaviors by combining with a homemade electrical impedance spectroscopy device. This method can reinforce the throughput of ICEO vortices and enables it to integrate with simple and economical sensors to accomplish disease diagnosis and environmental monitoring.

Four-wave mixing seeded by a rapid wavelength-sweeping FDML laser for nonlinear imaging at 900 nm and 1300 nm

Four-wave mixing (FWM) enables the generation and amplification of light in spectral regions where suitable fiber gain media are unavailable. The 1300 nm and 900 nm regions are of especially high interest for time-encoded (TICO) stimulated Raman scattering microscopy and spectro-temporal laser imaging by diffracted excitation (SLIDE) two-photon microscopy. We present a new, to the best of our knowledge, FWM setup where we shift the power of a home-built fully fiber-based master oscillator power amplifier (MOPA) at 1064 nm to the 1300-nm region of a rapidly wavelength-sweeping Fourier domain mode-locked (FDML) laser in a photonic crystal fiber (PCF) creating pulses in the 900-nm region. The resulting 900-nm light can be wavelength swept over 54 nm and has up to 2.5 kW (0.2 µJ) peak power and a narrow instantaneous spectral linewidth of 70 pm. The arbitrary pulse patterns of the MOPA and the fast wavelength tuning of the FDML laser (419 kHz) allow it to rapidly tune the FWM light enabling new and faster TICO-Raman microscopy, SLIDE imaging, and other applications.

Robust femtosecond-written chirped and tilted fiber Bragg gratings for Raman filtering in multi-kW fiber lasers

We present a robust chirped and tilted fiber Bragg grating (CTFBG) in a large-mode-area double-cladding fiber (LMA-DCF) written by a femtosecond (fs) laser. By implementing the fs-CTFBG into the output end of a high-power fiber laser for Raman filtering, a power handling capability of 4 kW is achieved with a Raman filtering ratio of ∼13 dB. To the best of our knowledge, this is the maximum handling power of a CTFBG for Raman filtering. The signal loss of the fs-CTFBG is 0.03 dB, which has little effect on the output laser beam quality. The air-cooled fs-CTFBG has a minimum temperature slope of 7.8°C/kW due to a self-annealing effect. This work proves the excellent performance of the fs-CTFBG, promoting the development of high-power CTFBGs.

Plug-and-play fiber-optic sensors based on engineered cells for neurochemical monitoring at high specificity in freely moving animals

In vivo detection of neurochemicals, including neurotransmitters and neuromodulators, is critical for both understanding brain mechanisms and diagnosing brain diseases. However, few sensors are competent in monitoring neurochemical dynamics in vivo at high specificity. Here, we propose the fiber-optic probes based on engineered cells (FOPECs) for plug-and-play, real-time detection of neurochemicals in freely moving animals. Taking advantages of life-evolved neurochemical receptors as key components, the chemical specificity of FOPECs is unprecedented. We demonstrate the applications of FOPECs in real-time monitoring of neurochemical dynamics under various physiology and pathology conditions. With no requirement of viral infection in advance and no dependence on animal species, FOPECs can be widely adopted in vertebrates, such as mice, rats, rabbits, and chickens. Moreover, FOPECs can be used to monitor drug metabolisms in vivo. We demonstrated the neurochemical monitoring in blood circulation systems in vivo. We expect that FOPECs will benefit not only neuroscience study but also drug discovery.

Bend-insensitive fiber optic ultrasonic tracking probe for cardiovascular interventions

BACKGROUND

Transesophageal echocardiography (TEE) is widely used to guide medical device placement in minimally invasive cardiovascular procedures. However, visualization of the device tip with TEE can be challenging. Ultrasonic tracking, enabled by an integrated fiber optic ultrasound sensor (FOUS) that receives transmissions from the TEE probe, is very well suited to improving device localization in this context. The problem addressed in this study is that tight deflections of devices such as a steerable guide catheter can result in bending of the FOUS beyond its specifications and a corresponding loss of ultrasound sensitivity.

PURPOSE

A bend-insensitive FOUS was developed, and its utility with ultrasonic tracking of a steerable tip during TEE-based image guidance was demonstrated.

METHODS

Fiberoptic ultrasound sensors were fabricated using both standard and bend insensitive single mode fibers and subjected to static bending at the distal end. The interference transfer function and ultrasound sensitivities were compared for both types of FOUS. The bend-insensitive FOUS was integrated within a steerable guide catheter, which served as an exemplar device; the signal-to-noise ratio (SNR) of tracking signals from the catheter tip with a straight and a fully deflected distal end were measured in a cardiac ultrasound phantom for over 100 frames.

RESULTS

With tight bending at the distal end (bend radius < 10 mm), the standard FOUS experienced a complete loss of US sensitivity due to high attenuation in the fiber, whereas the bend-insensitive FOUS had largely unchanged performance, with a SNR of 47.7 for straight fiber and a SNR of 36.8 at a bend radius of 3.0 mm. When integrated into the steerable guide catheter, the mean SNRs of the ultrasonic tracking signals recorded with the catheter in a cardiac phantom were similar for straight and fully deflected distal ends: 195 and 163.

CONCLUSION

The FOUS fabricated from bend-insensitive fiber overcomes the bend restrictions associated with the FOUS fabricated from standard single mode fiber, thereby enabling its use in ultrasonic tracking in a wide range of cardiovascular devices.

Sufentanil, dexmedetomidine combined with surface anesthesia for awake fiberoptic nasotracheal intubation in the patient with severe mouth opening difficulty undergoing wedge resection of the right upper lung: A case report and literature review

BACKGROUND

Severe mouth opening difficulty may increase the risk of airway management during anesthesia induction, and awake fiberoptic nasotracheal intubation (AFNI) is the first option for patients with orofacial anatomical changes.

CASE SUMMARY

A 54-year-old man was scheduled to undergo wedge resection of the right upper lung in August 2021. The patient had a history of enlarged right maxillary lesion resection and partial right maxillary resection surgery in April 2020, which led to orofacial anatomical changes and severe mouth opening difficulty. To avoid difficult airway-related emergency scenarios, the AFNI was successfully performed through intravenous injection of sufentanil and dexmedetomidine combined with lidocaine topical anesthesia under a conscious state without any uncomfortable feeling or complications.

CONCLUSIONS

Intravenous injection of sufentanil and dexmedetomidine combined with lidocaine topical anesthesia can be used as an alternative medication scheme to relieve uncomfortable suffering for AFNI in patients with severe mouth opening difficulty.

Position Statement of the Union of European Phoniatricians (UEP): Fees and Phoniatricians' Role in Multidisciplinary and Multiprofessional Dysphagia Management Team

The need for multidisciplinary and multiprofessional management of dysphagia is constantly increasing and creating a major challenge for healthcare professionals and society, especially in terms of professional expertise and human resources. The distribution of tasks among the dysphagia team members, which includes phoniatricians, otolaryngologists, and speech-language therapists, is flexible and overlapping. For assessing dysphagia, the (fibreoptic) flexible endoscopic evaluation of swallowing (FEES), with or without videofluoroscopy, is a pivotal diagnostic tool. This position paper aims to illustrate the phoniatrician's role in performing a FEES, which is an indispensable component of the diagnostic workup of patients suffering from oropharyngeal dysphagia. It is based on the current collaborative expert view of the Swallowing Committee of the Union of European Phoniatricians and a literature review. A FEES is one of the core competences of phoniatricians due to their endoscopic expertise and experience in the field of dysphagia and diseases of the upper aerodigestive tract. Therefore, the phoniatrician is an important member of the dysphagia team, for the medical diagnostics of the aerodigestive tract and dysphagia as well as for FEES. Phoniatric competence is especially important for head and neck cancer patients, infants, and complex cases.

Multiplexed optical fiber cell temperature sensing system with high sensitivity and accuracy

Significance

A multiplexed fiber laser sensing system for cell temperature is proposed. To the best of the authors' knowledge, this is the first multilongitudinal mode (MLM) optical fiber laser sensor array designed for cell temperature sensing.

Aim

A two-channel cell temperature sensing system with high sensitivity and real-time sensing capability is achieved. The temperature change of human hepatoellular carcinomas (HepG2) cells under the influence of exogenous chemical aflatoxin B1 (AFB1) can be monitored in real time.

Approach

A fiber laser cavity consists of a pair of fiber Bragg gratings (FBGs) with matched central wavelengths and a piece of erbium-doped fiber (EDF). The static FBG is utilized for design of fiber laser cavity and laser modes selection. In comparison, the sensing FBG is used for cell temperature sensing. The sensing FBG has a length of 10 mm and a diameter of 200    μ m . Beat frequency signals (BFS) are generated by MLM lasers after optical-to-electrical conversion at a photodetector. Frequency change of a BFS is closely related to the reflected wavelength change of the sensing FBG. Through frequency division multiplexing, two fiber laser cavities are designed in the sensing system for two-channel temperature sensing. Frequency shift of a BFS that represents temperature change of cells can be automatically recorded in seconds.

Results

A two-channel cell temperature sensing system is designed with high sensitivities of 101.62 and 119.82    kHz / ° C , respectively. The temperature change of HepG2 cells under the influence of exogenous chemical AFB1 is monitored in real time.

Conclusions

The proposed system has the advantages of simple structure, high sensitivity, and two-channel sensing capability. Our study provides a simple and effective method to design a fiber laser sensor system without complex demodulation techniques and expensive optical components.

Accuracy of Intracranial Pressure Monitoring-Single Centre Observational Study and Literature Review

Intracranial hypertension and adequacy of brain blood flow are primary concerns following traumatic brain injury. Intracranial pressure (ICP) monitoring is a critical diagnostic tool in neurocritical care. However, all ICP sensors, irrespective of design, are subject to systematic and random measurement inaccuracies that can affect patient care if overlooked or disregarded. The wide choice of sensors available to surgeons raises questions about performance and suitability for treatment. This observational study offers a critical review of the clinical and experimental assessment of ICP sensor accuracy and comments on the relationship between actual clinical performance, bench testing, and manufacturer specifications. Critically, on this basis, the study offers guidelines for the selection of ICP monitoring technologies, an important clinical decision. To complement this, a literature review on important ICP monitoring considerations was included. This study utilises illustrative clinical and laboratory material from 1200 TBI patients (collected from 1992 to 2019) to present several important points regarding the accuracy of in vivo implementation of contemporary ICP transducers. In addition, a thorough literature search was performed, with sources dating from 1960 to 2021. Sources considered to be relevant matched the keywords: "intraparenchymal ICP sensors", "fiberoptic ICP sensors", "piezoelectric strain gauge sensors", "external ventricular drains", "CSF reference pressure", "ICP zero drift", and "ICP measurement accuracy". Based on single centre observations and the 76 sources reviewed in this paper, this material reports an overall anticipated measurement accuracy for intraparenchymal transducers of around ± 6.0 mm Hg with an average zero drift of <2.0 mm Hg. Precise ICP monitoring is a key tenet of neurocritical care, and accounting for zero drift is vital. Intraparenchymal piezoelectric strain gauge sensors are commonly implanted to monitor ICP. Laboratory bench testing results can differ from in vivo observations, revealing the shortcomings of current ICP sensors.

Recent Advancements of LSPR Fiber-Optic Biosensing: Combination Methods, Structure, and Prospects

Fiber-optic biosensors based on localized surface plasmon resonance (LSPR) have the advantages of great biocompatibility, label-free, strong stability, and real-time monitoring of various analytes. LSPR fiber-optic biosensors have attracted extensive research attention in the fields of environmental science, clinical medicine, disease diagnosis, and food safety. The latest development of LSPR fiber-optic biosensors in recent years has focused on the detection of clinical disease markers and the detection of various toxic substances in the environment and the progress of new sensitization mechanisms in LSPR fiber-optic sensors. Therefore, this paper reviews the LSPR fiber-optic sensors from the aspects of working principle, structure, and application fields in biosensors. According to the structure, the sensor can be divided into three categories: traditional ordinary optical fiber, special shape optical fiber, and specialty optical fiber. The advantages and disadvantages of existing and future LSPR fiber-optic biosensors are discussed in detail. Additionally, the prospect of future development of fiber-optic biosensors based on LSPR is addressed.

Development of a core-offset-based SMS fiber structure for detection of various biomolecules

This paper discusses the details about the fabrication of single-mode fiber (SMF)- and multi-mode fiber (MMF)-based core-offset sensor structures for biomolecules detection. SMF-MMF-SMF (SMS) and SMF-core-offset MMF-SMF (SMS structure with core-offset) are proposed in this paper. In the conventional SMS structure the incident light is introduced from the SMF to the MMF and then passes through the MMF to the SMF. However, in the SMS-based core offset structure (COS) the incident light is introduced from the SMF to the core offset MMF and then passes through the MMF to the SMF, and more incident light leaks at the fusion point between the SMF and the MMF. This structure causes more incident light to leak out from the sensor probe, forming evanescent waves. By analyzing the transmitted intensity, the performance of COS can be improved. The results show that the structure of the core offset has great potential for the development of fiber-optic sensors.

Breakage Costs in Flexible Ureteroscopy: Digital vs. Fiberoptic Modalities

OBJECTIVE

To compare the maintenance costs of digital flexible ureteroscopes (DFU) versus fiberoptic flexible ureteroscopes (FFU) to understand the long-term financial impact associated with breakage in a flexible ureteroscopy (f-URS) program.

METHODS

Data for breakage of FFU and DFU at an academic institution from 2019 to 2021 were obtained from our vendor (Karl Storz) and analyzed by month. Correlation test was used to evaluate significant differences in number of procedures, number of breakage events, breakage rates, and repair cost per month. Cumulative analyses were utilized to examine the number of procedures before failure (time to failure - TTF) and repair costs per procedure (RCpP).

RESULTS

We performed a total of 2,154 f-URS, including 1,355 with FFU and 799 with DFU (P<.001). Although we found a higher number of breakage events in FFU (n=124) than DFU (n=73) (P<.001), the overall breakage rate was similar, 9.9% vs. 8.8%, respectively (P=0.86). On cumulative analysis, both modalities reached the same TTF plateau (11 cases) after 18 months. After 400 cases, the RCpP for DFU was 1.25 times higher than for FFU (P=0.04).

CONCLUSION

Overall, we found no difference in overall scope breakage rates between DFU and FFU. Although there was no difference in TTF over time, at the beginning DFU displayed considerable higher durability, leading to lower RCpP. Furthermore, DFU's endurance leveled off to FFU over time, resulting in higher RCpP after 400 cases. This finding may be explained by the presence of renewed scopes after repair.