Flexible Fiber Research Articles

Temperature sensing of the brain enabled by directly inscribed Bragg gratings in CYTOP polymer optical fiber implants

Brain temperature is a vital physiological parameter that has a great effect on metabolic processes, enzymatic activity, neurotransmitter function, blood flow regulation, neuroprotection, and cognitive performance. In this framework, the development of accurate and reliable brain temperature measurement tools is crucial in brain-related treatment and research, such as neurosurgery, therapeutic hypothermia, and the understanding of brain function and pathologies. Here, we developed the first large-core flexible low optical loss CYTOP polymer optical fiber (POF)-based brain temperature probe operating in the telecommunication spectral range. The temperature measurements were achieved by detecting the reflected spectrum from a fiber Bragg grating (FBG) directly inscribed at the tip of the POF using femtosecond pulses. A fluorinated ethylene propylene (FEP) tube was thermally drawn and used as a sleeve around the FBG structure to eliminate the cross-sensitivity with humidity and microstrain perturbations. The assembled POF implant has a sensitivity of 14.3 pm/°C. The local temperature of the cerebral cortex, corpus callosum, and striatum in a rat brain was measured in vivo. The results indicate that the deep brain regions have higher temperature than the top cortical ones with a relatively linear relationship between the brain structure depth and its temperature. In addition, the rectal body core temperature was detected in parallel with the brain temperature measurement to further validate the developed device. We believe that the presented CYTOP POF-based implantable temperature probe opens the way towards the development of flexible and stable tools for accurate brain temperature recording where large-core fiber-based neural devices are required.

Flexible optical fiber channel modeling based on a neural network module.

Optical fiber channel modeling, which is essential in optical transmission system simulations and designs, is usually based on the split-step Fourier method (SSFM), making the simulation quite time-consuming owing to the iteration steps. Here, we train a neural network module termed NNSpan to learn the transfer function of a single fiber (G652 or G655) span with a length of 80 km and successfully emulate long-haul optical transmission systems by cascading multiple NNSpans, which gives remarkable prediction accuracy, even over a transmission distance of 1000 km. Even when trained without erbium-doped fiber amplifier (EDFA) noise, NNSpan performs quite well when emulating the systems affected by EDFA noise. An optical bandpass filter can optionally be added after EDFA, making the simulation more flexible. Comparison with the SSFM shows that NNSpan has a distinct computational advantage, with the computation time reduced by a factor of 12. This method based on NNSpan could be a supplementary option for optical transmission system simulations, thus contributing to system designs as well.

Near-infrared and hysteroscopy-guided robotic excision of uterine isthmocele with laser fiber: a novel high-precision technique

To describe a novel high-precision technique for robotic excision of uterine isthmocele, employing a carbon dioxide laser fiber, under hysteroscopic guidance, and near-infrared guidance. Video article. A 36-year-old multipara with three prior cesarean sections presented to our infertility clinic with secondary infertility. The patient had been trying to conceive for 6 months without success. The patient underwent a hystero-salpingo contrast sonography which identified a large cesarean scar defect with a 1.4 mm residual myometrial thickness (RMT). The patient was counseled on surgical management with robotic approach due to RMT < 3 mm precluding her from hysteroscopic resection and the potential risk for a cesarean scar ectopic or abnormal placentation if she were to become pregnant in the future. She elected to undergo excision and repair and informed consent was obtained from the patient. The robot was docked for traditional gynecologic robotic surgery. The uterus was injected with 5 units of vasopressin. We used a carbon dioxide laser fiber (Lumenis® FIberLase) at a power of 5 watts as the sole energy source for dissection. The bladder was dissected off the uterus to identify the general area of the isthmocele. At that point, diagnostic hysteroscopy was performed using a 30-degree 5 mm hysteroscope (Karl Storz®) to identify and enter the isthmocele. Near-infrared vision (da Vinci Firefly®, Intuitive USA) was activated to precisely outline the extent of the isthmocele, which was not visible with simple transillumination from the hysteroscope. We proceeded with laser excision in infrared/grey scale using the laser at a power of 20 watts removing the entire area that was highlighted by the Firefly®. After full excision of the isthmocele, the hysteroscope was removed and was eventually replaced by a uterine manipulator (ConMed VCare DX®). The hysterotomy was closed with a two layer closure: 4 mattress sutures of 2-0 Vicryl (Ethicon®) followed by a running 2-0 PDS Stratafix (Ethicon®). The peritoneal layer was closed over these two layers with 2-0 PDS Stratafix (Ethicon®) in a running fashion. The uterine manipulator was removed and a 14 French Malecot catheter (Bard®) was placed in the uterine cavity to allow the healing to proceed with minimal risk of cervical stenosis. The bladder was backfilled to ensure integrity of the bladder wall. Interceed adhesion barrier (Gynecare®) was then placed over the area of the repair and the procedure was concluded. The patient included in this video gave consent for publication of the video and posting of the video online including social media, the journal website, scientific literature websites (such as PubMed, ScienceDirect, Scopus, etc.) and other applicable sites. Completion of excision and repair of cesarean scar defect without surgical complications. Robotic excision and repair of a sizable uterine isthmocele with carbon dioxide laser fiber and da Vinci Firefly® was completed successfully without any surgical complications. Diagnostic hysteroscopy was used to positively identify the isthmocele and provide transillumination. However, the thickness of the cervical myometrium only allows the hysteroscopic light to shine through the thinnest portion of myometrium at the apex of the isthmocele, while the near-infrared vision allowed by the da Vinci Firefly® technology was used to precisely identify the borders of the defect. The carbon dioxide laser was used to completely remove the defect while avoiding damage to delicate reproductive tissue and over-excision. No complications were identified during the postoperative visit. MRI three months after the surgery revealed a RMT of 10 mm at the location of excision compared to the initial RMT of 1.4 mm. Currently, there is no gold-standard technique for surgical management of isthmocele. This is the first description of the combined use of hysteroscopy, near-infrared vision and laser fiber for the robotic excision of isthmocele. This specific setup proves to be a useful technical improvement. The use of near-infrared vision combined with precise hysteroscopic targeting allows much clearer definition of the isthmocele borders, and the flexible laser fiber allows millimetric excision in the absence of appreciable lateral thermal spread. Further investigation is warranted to identify a gold standard surgical technique for patients with CSD.

A photocatalytic-microbial coupling system for simultaneous removal of harmful algae and enhanced denitrification: Construction, performance and mechanism of action

Recently, harmful algal blooms (HABs) have become occurred with increasingly frequency worldwide. High nitrate content is one of the primary causes of eutrophication. Research has shown that photocatalytic materials enhance the effectiveness of microbial denitrification while removing other contaminants, despite some shortcomings. Based on this, we loaded TiO2/C3N4 heterojunctions onto weaveable, flexible carbon fibers and established a novel photocatalytically enhanced microbial denitrification system for the simultaneous removal of harmful algae and Microcystin-LR. We found that 99.35% of Microcystis aeruginosa and 95.34% of MC-LR were simultaneously and effectively removed. Compared to existing denitrification systems, the nitrate removal capacity improved by 72.33%. The denitrifying enzyme activity and electron transport system activity of microorganisms were enhanced by 3.54–3.86 times. Furthermore, the microbial community structure was optimized by the regulation of photogenerated electrons, and the relative abundance of main denitrifying bacteria increased from 50.72% to 66.45%, including Proteobacteria and Bacteroidetes. More importantly, we found that the increased secretion of extracellular polymeric substances by microorganisms may be responsible for the persistence of the reinforcing effect caused by photogenerated electrons in darkness. The higher removal of Microcystis aeruginosa and Microcystin-LR (MC-LR) achieved by the proposed system would reduce the frequency of HAB outbreaks and prevent the associated secondary pollution.

Comparison of printability and mechanical properties of rigid and flexible fiber-reinforced 3D printed cement-based materials

Since eco-friendly, labor-saving construction technologies are urgently needed than ever, concrete 3D printing technology has gained increasing attention. However, there are still limited studies focusing on reinforcement techniques for 3D printed cement-based materials (3DPCM) which restrict their applications. Herein, we revealed the differences between the influence of typical rigid and flexible fibers on the printability and mechanical properties of 3DPCM. Printability, including buildability and extrudability, was evaluated via fluidity and shape stability tests and verified by printing experiments. The anisotropy ratio was proposed to assess the anisotropic mechanical properties. Furthermore, the fracture energy and bend-press ratio were adopted to assess the toughness. Results indicate that steel, polypropylene (PP) and polyvinyl alcohol (PVA) fibers all increase the buildability but decrease the extrudability of 3DPCM. Compared to steel fibers, PP and PVA fibers have a greater impact on the printability owing to their entanglement. The alignment and wall effect of steel fiber drastically increase the anisotropy in the compressive strength of 3DPCM. PP fibers also intensify the anisotropy in the compressive strength due to their filling effect. Low content of steel fibers and PP fibers both have limited impacts on the toughness and the anisotropy in flexural strength of 3DPCM. The fracture energy of 3DPCM for the loading direction perpendicular to the interface is higher than that for the direction parallel to the interface. Contrary to PP fibers, samples with steel fibers have higher bend-press ratios once the loading direction is parallel to the interface.

Organic dye fluorescent fibers for wearable devices

Organic fluorescent dyes are gradually gaining wide application in the fields of sensors, displays, and lighting. However, the use of organic fluorescent dyes for White light-emitting diodes (WLEDs) is still not sufficiently studied to be applied to the market. In this study, FR and FG with red and green fluorescence emission, respectively, were designed and synthesized, and two fluorescent dyes FB and FBP with aggregation-induced luminescence (AIE) properties were selected and dissolved in polyacrylonitrile (PAN) solution (in the ratio of 0.15 wt%, 2 wt%, 2 wt%, 1 wt%, respectively) to make flexible fiber films with fluorescence emission by electrostatic spinning. These fluorescent fiber films still have 78% of luminescence intensity after five days of immersion in water. The fluorescence quantum yields of the four fiber membranes were 12.89% (FR/PAN), 6.23% (FG/PAN), 39.85% (FB/PAN), 11.51% (FBP/PAN), respectively. Then 460 nm light-emitting diode (LED) chips and 365 nm LED chips were used to make WLEDs respectively with their color product coordinates (CIEs) of (0.3176,0.3256) and (0.3144,0.3158). Based on the good flexibility and mechanical strength of the fiber films, we used them to fabricate the wearable bracelet. The results indicate that the organic dye-based fluorescent fiber film has good potential for application in the field of WLED and wearable devices.

Electrospinning Fabrication of PA66 Colloidal Crystal Fibers with Various Morphologies

Abstract: Colloidal crystal (CC) fiber has unique light manipulation properties, fiber flexibility, and the potential to be used in the textile industry as an alternative to chemical dyes. Introducing polyamide 66 (PA66) into CC fiber can effectively improve the performance of fibers. In this study, polyamide 66 (PA66) CC fibers with various morphologies were fabricated by electrospinning using high-tensile PA66 and P(St-MMA-AA) latex particles as raw materials, such as closepacked, inlaid, noodle-like, spindle knots, bamboo-like, semi-enclosed, hat-like, etc. The formation mechanism of various fibers was analyzed based on the phase separation and assembly interaction. The prepared PA66 CC fiber film was reported to have unique structural color and enhanced mechanical properties, which can be used as a substrate for drawing various patterns. This work will provide a novel idea for the fabrication of functional CC fiber, which is helpful for the potential applications in the textile industry.

Study to establish fiberoptic laryngoscopy as a diagnostic and investigation tool for laryngotracheal stenosis and to use the same for prognosis of the disease: retrospective analysis

Background: Laryngotracheal stenosis is a common benign condition of airway obstruction in both the pediatric and adult age group. This could either be acquired or congenital, in which there is narrowing of either the portions of the larynx or trachea making it difficult to breathe. This condition can be managed by several operative and endoscopic procedures. Flexible fiber optic laryngoscope is an excellent tool in the diagnostic investigation of laryngotracheal stenosis. Methods: This is a retrospective study that was done with data collected from the medical records department of patients diagnosed with laryngotracheal stenosis in a tertiary care hospital in the last 10 years. Results: A total of 22 patients who underwent FFL exam were taken for this retrospective study and the results were analyzed. Conclusions: This study proves that Fiberoptic laryngoscopy is a single modality diagnostic tool, which is useful in diagnosing, and localizing stenotic lesions in the Laryngotracheal region. It is cheap, less invasive and trained Otolaryngologist can perform this as an outpatient procedure. This therefore reduces the exposure to harmful radiation caused by repeated computed tomography scans.

An extendable optical fibre probe survey meter for naturally occurring radioactive material (NORM) and other weak emitters

We have developed a radioluminescence-based survey meter for use in industries in which there is involvement in naturally occurring radioactive material (NORM), also in support of those needing to detect other weak emitters of radiation. The functionality of the system confronts particular shortcomings of the handheld survey meters that are currently being made use of. The device couples a LYSO:Ce scintillator with a photodetector via a polymer optical fibre waveguide, allowing for "intrinsically safe" inspection within pipework, separators, valves and other such component pieces. The small-diameter optical fibre probe is electrically passive, immune to electromagnetic interference, and chemically inert. The readout circuit is entirely incorporated within a handheld casing housing a silicon photomultiplier (SiPM) detection circuit and a microprocessor circuit connected to an LCD display. A 15 m long flexible PMMA optical fibre waveguide is butt coupled to an ABS plastic probe that retains the LYSO:Ce scintillator. Initial tests have included the use of lab-based mixed gamma-ray sources, measurements being made in concert with a reference conventional GM survey-meter. Characterization, via NORM sources at a decontamination facility, has shown useful sensitivity, covering the dose-rate range 0.10- to 28 µSv h−1 (R-squared 0.966), extending to 80 µSv/h as demonstrated in use of a Cs-137 source. The system is shown to provide an effective tool for detection of radioactivity within hard to access locations, in particular for sources emitting at low radiation levels, down to values that approach background.

A novel strategy for large-scale preparation of flexible high-conductivity carbon fiber paper for supercapacitors

In order to solve the problems of high cost and high brittleness of commercial carbon fiber paper, a low-cost mass production method of carbon fiber paper for flexible super capacitor was proposed. The dispersant CMC-Na is utilized to achieve uniform dispersion of chopped carbon fiber in a water system through ultrasonic dispersion. Sheath-core composite (PE/PET) fiber not only enhances the tensile strength of CFP but also consolidates the electrode network structure formed based on carbon fiber structure. The CFP-3 electrode, impregnated with 3 % AC phenolic resin, exhibits excellent mechanical and electrochemical properties. SEM images reveal that AC is deposited on each carbon fiber and that the CFP-3 electrode retains its three-dimensional structure (with a porosity of 71.2 %), providing an effective permeation path for electrons (with an electrical conductivity of 0.871 S m−1). The CFP-3 electrode can restore its original shape after folding and bending without damage. Electrochemical tests demonstrate that the CFP-3 electrode has a high areal capacitance of 507.2 mF cm−2 at a current density of 0.5 mA cm−2. At a current density of 10 mA cm−2, the capacitance retention rate of the CFP-3 electrode is 96.1 % after 5000 charge-discharge cycles, owing to the well-interconnected structure of the carbon fiber paper. Furthermore, when used as a direct electrode, CFP exhibits excellent stability. Most notably, the cost of producing the CFP-3 electrode (0.0314 m2) is only $0.195, significantly lower than that of commercial products, excluding equipment, utilities, and labor costs. This research provides valuable insights for the low-cost, large-scale production of paper-based flexible supercapacitors.

The intriguing bifunctional effect of strong metal support interaction (SMSI) and hydrogen spillover effect (HSPE) for effective hydrogen evolution reaction

The mechanistic insights behind the kinetics of Hydrogen evolution reaction are unraveled through the bifunctional effect - Strong Metal Support Interaction (SMSI) and Hydrogen Spillover Effect (HSPE) on the WO3 hexagonal nanorods decorated with gold clusters and supported on the reduced graphene layers. The investigation is extended to scaling the electrocatalyst in a flexible electrode-carbon fiber for robust hydrogen evolution reaction in broad pH spectra. The research found that the proposed electrocatalyst demonstrated a reduced overpotential of 20 mV at a current density of 10 mA cm2 in acidic conditions and the stability of the ternary catalyst was verified through the Pourbaix profile. The Tafel slope was also comparable to that of the noble metal electrocatalyst Pt/C, with values of 35 mV dec–1 in 0.5 M H2SO4. The study demonstrated the potential for large-scale application of the proposed catalyst with stable operation observed for 24 h.

Vision-Based Contact Adhesion Measurement Method on Soft Matter Surfaces.

Adhesion property measurements contribute to a comprehensive understanding of the mechanical properties of soft matters. Indentation tests are a common method for measuring the adhesion force. However, indenters generally have a large volume and a small sensing angle and, thus, are not conducive to local detection in high-precision environments. Here, we propose a vision-based contact adhesion measurement (VisCAM) method to achieve the contact image and adhesion force on soft matter surfaces from the perspective of indentation direction. The coupling of the 7.6 mm diameter probe and a flexible fiber makes the system similar to a miniaturized endoscope. Classical contact theories and finite element models are used for the contact mechanics analysis of silicone rubber. The image grayscale-load mathematical model is constructed based on the change in contact light spot. Finally, the uncertainty of the system is less than 4%, and the measurement error is 0.04 N. In-vitro kidney indentation experiments showed that the local adhesion force measurement of soft tissues can be completed. Our method provides better solutions for understanding the adhesion properties of soft matters.

Robust real-time imaging through flexible multimode fibers

Conventional endoscopes comprise a bundle of optical fibers, associating one fiber for each pixel in the image. In principle, this can be reduced to a single multimode optical fiber (MMF), the width of a human hair, with one fiber spatial-mode per image pixel. However, images transmitted through a MMF emerge as unrecognizable speckle patterns due to dispersion and coupling between the spatial modes of the fiber. Furthermore, speckle patterns change as the fiber undergoes bending, making the use of MMFs in flexible imaging applications even more complicated. In this paper, we propose a real-time imaging system using flexible MMFs, but which is robust to bending. Our approach does not require access or feedback signal from the distal end of the fiber during imaging. We leverage a variational autoencoder to reconstruct and classify images from the speckles and show that these images can still be recovered when the bend configuration of the fiber is changed to one that was not part of the training set. We utilize a MMF 300 mm long with a 62.5 μm core for imaging 10~times ~10 cm objects placed approximately at 20 cm from the fiber and the system can deal with a change in fiber bend of 50^circ and range of movement of 8 cm.

Liquid Metal Fibers with a Knitted Structure for Wearable Electronics.

Flexible conductive fibers have shown tremendous potential in diverse fields, including health monitoring, intelligent robotics, and human-machine interaction. Nevertheless, most conventional flexible conductive materials face challenges in meeting the high conductivity and stretchability requirements. In this study, we introduce a knitted structure of liquid metal conductive fibers. The knitted structure of liquid metal fiber significantly reduces the resistance variation under tension and exhibits favorable durability, as evidenced by the results of cyclic tensile testing, which indicate that their resistance only undergoes a slight increase (<3%) after 1300 cycles. Furthermore, we demonstrate the integration of these liquid metal fibers with various rigid electronic components, thereby facilitating the production of pliable LED arrays and intelligent garments for electrocardiogram (ECG) monitoring. The LED array underwent a 30 min machine wash, during which it consistently retained its normal functionality. These findings evince the devices' robust stable circuit functionality and water resistance that remain unaffected by daily human activities. The liquid metal knitted fibers offer great promise for advancing the field of flexible conductive fibers. Their exceptional electrical and mechanical properties, combined with compatibility with existing electronic components, open new possibilities for applications in the physiological signal detection of carriers, human-machine interaction, and large-area electronic skin.

An Antifouling Redox Sensor with a Flexible Carbon Fiber Electrode for Machine Learning-Based Dissolved Oxygen Prediction in Severely Eutrophic Waters

Machine-learning-based models are used to predict dissolved oxygen (DO); however, acquiring continuous water quality data for input variables in harsh environments remains challenging. Herein, redox potential (ORP) determined by a thermo-treated flexible carbon fiber electrode was introduced as a single or preferential input variable for machine-learning-based DO prediction in a year-round eutrophic estuary. The novel ORP sensor was operated for 4 months, and DO was predicted from ORP and six water quality data sources using a long short-term memory (LSTM) neural network. ORP and DO concentration showed a linear correlation, but the first-order correlation slopes varied seasonally. The optimal LSTM hyperparameters were proposed, which depended on the prediction time step and predictor case. Simulation results showed higher seasonal DO dynamics reproduced using ORP alone (RMSE = 1.09) than that predicted using six other water quality parameters (RMSE = 1.32). In addition, ORP played a key role in DO prediction when combined with all water quality parameters (RMSE = 1.08). The feature importance of ORP as a predictor was evaluated from a random forest model. Overall, the highly selective redox sensor has a distinct response to DO concentration and offers a novel and cost-effective approach for monitoring or predicting DO in eutrophic waters.

A miniature fiber optic ablation probe manufactured via ultrafast laser inscription and selective chemical etching

Picosecond laser ablation has recently emerged as a minimally invasive alternative to conventional surgical resection of early tumors, offering high precision and limited thermal damage to surrounding tissue. Potential clinical application routes include deployment through the working channels of endoscopes or needle bores, which require the delivery of ultrashort high energy pulses through flexible optical fibers with focusing optics at the distal end. The manufacture of distal end optical systems for fiber ablation is challenging, inhibiting translation toward clinical applications. Here, we present a miniature fiber-coupled ablation probe developed using ultrafast laser inscription and chemical etching, employing a hollow-core fiber for pulse delivery. Its design, fabrication, and characterization are detailed, along with a feasibility demonstration for the ablation of stainless steel and chicken tissue.

The invisible plant technology of Prehistoric Southeast Asia: Indirect evidence for basket and rope making at Tabon Cave, Philippines, 39-33,000 years ago.

A large part of our material culture is made of organic materials, and this was likely the case also during prehistory. Amongst this prehistoric organic material culture are textiles and cordages, taking advantage of the flexibility and resistance of plant fibres. While in very exceptional cases and under very favourable circumstances, fragments of baskets and cords have survived and were discovered in late Pleistocene and Holocene archaeological sites, these objects are generally not preserved, especially in tropical regions. We report here indirect evidence of basket/tying material making found on stone tools dating to 39-33,000 BP from Tabon Cave, Palawan Philippines. The distribution of use-wear on these artefacts is the same as the distribution observed on experimental tools used to thin fibres, following a technique that is widespread in the region currently. The goal of this activity is to turn hard plant segments into supple strips suitable as tying material or to weave baskets, traps, and even boats. This study shows early evidence of this practice in Southeast Asia and adds to the growing set of discoveries showing that fibre technology was an integral part of late Pleistocene skillset. This paper also provides a new way to identify supple strips of fibres made of tropical plants in the archaeological record, an organic technology that is otherwise most of the time invisible.

Ultra-flexible Al2O3 fibers: A novel catalyst support material for sustainable catalysis

Flexible aluminum oxide (Al2O3) fibers were prepared by the blow spinning method and their potential as a high-temperature catalyst support was investigated. The synthesized Al2O3 fibers exhibited remarkable flexibility in both mechanical compression and recovery tests, which remained intact in a wide temperature range from −196 °C to 1200 °C. Moreover, their low thermal conductivity of 0.030 W K−1∙m−1, demonstrated an outstanding thermal insulation. Subsequently, nickel nanoparticles were uniformly distributed on the surface of the Al2O3 fibers as a self-supporting catalyst using a conventional impregnation method. The resulting self-supporting Ni/Al2O3 catalyst demonstrated remarkable thermo-catalytic performance and re-activation capability at high temperatures for thermocatalytic reaction of dry reforming of methane (DRM). Our findings highlight the potential of pure Al2O3 flexible fibers as a versatile material for various industrial applications, including high-temperature catalysis.

Synergies between Fibrillated Nanocellulose and Hot-Pressing of Papers Obtained from High-Yield Pulp.

To extend the application of cost-effective high-yield pulps in packaging, strength and barrier properties are improved by advanced-strength additives or by hot-pressing. The aim of this study is to assess the synergic effects between the two approaches by using nanocellulose as a bulk additive, and by hot-pressing technology. Due to the synergic effect, dry strength increases by 118% while individual improvements are 31% by nanocellulose and 92% by hot-pressing. This effect is higher for mechanical fibrillated cellulose. After hot-pressing, all papers retain more than 22% of their dry strength. Hot-pressing greatly increases the paper's ability to withstand compressive forces applied in short periods of time by 84%, with a further 30% increase due to the synergic effect of the fibrillated nanocellulose. Hot-pressing and the fibrillated cellulose greatly decrease air permeability (80% and 68%, respectively) for refining pretreated samples, due to the increased fiber flexibility, which increase up to 90% using the combined effect. The tear index increases with the addition of nanocellulose, but this effect is lost after hot-pressing. In general, fibrillation degree has a small effect which means that low- cost nanocellulose could be used in hot-pressed papers, providing products with a good strength and barrier capacity.

The saclayvirus Aci01-1 very long and complex fiber and its receptor at the Acinetobacter baumannii surface.

The Acinetobacter baumannii bacteriophage Aci01-1, which belongs to the genus Saclayvirus of the order Caudoviricetes, has an icosahedral head and a contractile rigid tail. We report that Aci01-1 has, attached to the tail conical tip, a remarkable 146-nm-long flexible fiber with seven beads and a terminal knot. Its putative gene coding for a 241.36-kDa tail fiber protein is homologous to genes in Aci01-1-related and unrelated phages. Analysis of its 3D structure using AlphaFold provides a structural model for the fiber observed by electron microscopy. We also identified a putative receptor of the phage on the bacterial capsule that is hypothesized to interact with the Aci01-1 long fiber.