AI-assisted smartphone-based colorimetric biosensor for visualized, rapid and sensitive detection of pathogenic bacteria.

Accurate and effective detection is essential to against bacterial infection and contamination. Novel biosensors, which detect bacterial bioproducts and convert them into measurable signals, are attracting attention. We developed an artificial intelligence (AI)-assisted smartphone-based colorimetric biosensor for the visualized, rapid, sensitive detection of pathogenic bacteria by measuring the bacteria secreted hyaluronidase (HAase). The biosensor consists of the chlorophenol red-ß-D-galactopyranoside (CPRG)-loaded hyaluronic acid (HA) hydrogel as the bioreactor and the ß-galactosidase (ß-gal)-loaded agar hydrogel as the signal generator. The HAase degrades the bioreactor and subsequently determines the release of CPRG, which could further react with ß-gal to generate signal colors. The self-developed YOLOv5 algorithm was utilized to analyze the signal colors acquired by smartphone. The biosensor can provide a report within 60 min with an ultra-low limit of detection (LoD) of 10 CFU/mL and differentiate between gram-positive (G+) and gram-negative (G-) bacteria. The proposed biosensor was successfully applied in various areas, especially the evaluation of infections in clinical samples with 100% sensitivity. We believe the designed biosensor has the potential to represent a new paradigm of "ASSURED" bacterial detection, applicable for broad biomedical uses.

Lumbosacral Plexogram: An Aid to Reconstructive Nerve Possibilities in the Lower Extremity.

The lumbosacral plexus is the network of nerves responsible for the motor and sensory function of the pelvis and lower limb. Our observation is that the anatomy of this plexus is less familiar to surgeons than that of the brachial plexus. Damage to the lumbosacral plexus and its terminal branches may have a significant impact on locomotion, posture, and stability. We have designed a visual representation of the lumbosacral plexus to aid clinicians treating peripheral nerve disorders. The utility is illustrated with a case report in which a patient underwent nerve transfers in the lower limb to restore function. A visual representation of the lumbosacral plexus is a valuable adjunct to a clinical examination and helps make sense of clinical signs. The color-coding of each root level and the arrangement of muscles from proximal to distal helps with visual recall. A clear assessment of complex lumbosacral plexus patients is essential for diagnosis and planning. As with the case described, a sound knowledge of the "plexogram" can identify solutions for complex patients and result in significant functional improvements. We hope it helps advance the field of nerve surgery and, particularly, nerve transfers.

Integrated Rayleigh wave streaming-enhanced sensitivity of shear horizontal surface acoustic wave biosensors.

Shear horizontal surface acoustic wave (SH-SAW) sensors are regarded as a promising alternative for label-free, sensitive, real time and low-cost detection. Nevertheless, achieving high sensitivity with SH-SAW has approached its limit imposed by the mass transport and probe-target affinity. We present here an SH-SAW biosensor accompanied by a unique Rayleigh wave-based actuator. The platform assembled on an ST-quartz substrate consists of dual-channel SH-SAW delay lines fabricated along a 90°-rotated direction, whilst another interdigital electrode (IDT) is orthogonally placed to generate Rayleigh waves so as to induce favourable streaming in the bio-chamber, enhancing the binding efficiency of the bio-target. Theoretical foundation and simulation have shown that Rayleigh acoustic streaming generates a level of agitation that accelerates the mass transport of the biomolecules to the surface. A fourfold improvement in sensitivity is achieved compared with conventional SH-SAW biosensors by means of complementary DNA hybridization with the aid of the Rayleigh wave device, giving a sensitivity level up to 6.15 Hz/(ng/mL) and a limit of detection of 0.617 ng/mL. This suggests that the proposed scheme could improve the sensitivity of SAW biosensors in real-time detection.

Photothermal Ferrotherapy - Induced Immunogenic Cell Death via Iron-Based Ternary Chalcogenide Nanoparticles Against Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is highly malignant and prone to recurrence and metastasis. Patients with TNBC have limited therapeutic options, often resulting in poor prognosis. Some new treatments for TNBC have been considered in the past decade, such as immunotherapy, photothermal therapy (PTT), and ferroptosis therapy, that allow the rapid and minimally invasive ablation of cancer. However, a multifunctional nanodrug system with more potent efficacy for TNBC is still needed. The use of iron-based ternary chalcogenide nanoparticles (NPs), namely AgFeS2 , is reported, which synergistically combines photothermal therapy, ferrotherapy, and immunotherapy in one system for the treatment of TNBC. AgFeS2 possesses excellent photothermal conversion performance for tumor near-infrared (NIR) phototherapy. Upon photoirradiation, these NPs generate heat, accelerate the release of iron ions, and effectively catalyze the Fenton reaction, resulting in cell apoptosis and ferroptosis. Additionally, AgFeS2 promotes the release of tumor-specific antigens and triggers an immune response via immunogenic cell death (ICD), thereby providing unique synergistic mechanisms for cancer therapy. The present study demonstrates the great potential of iron-based ternary chalcogenide as a new therapeutic platform for a combination of photothermal therapy, ferrotherapy, and immunotherapy for the suppression of TNBC.

Versatility of the double fascicular transfer in reconstruction of elbow flexion paralysis: Intermediate term follow-up and patient-related outcome measures.

OBJECTIVES: The use of fascicle transfers in the reconstruction of traumatic brachial plexus injury is well established, but limited evidence is available regarding their use in atraumatic elbow flexion paralysis. This retrospective case review aimed to verify whether median and ulnar fascicle transfers are similarly effective in atraumatic versus traumatic elbow flexion paralysis when measured using the British Medical Research Council (MRC) scale, Brachial plexus Assessment Tool (BrAT) and Stanmore Percentage of Normal Elbow Assessment (SPONEA) scores at long-term follow-up. METHODS: All median and ulnar fascicle transfer cases performed at the Queen Elizabeth Hospital Birmingham between August 2007 and November 2018 were reviewed to compare the outcomes of transfers performed for traumatic and atraumatic indications. Data on patient demographics, mechanism and nature of injury, date of injury or symptom onset, date of operation, and other nerve transfers performed were collected. Outcome measures collected included the British MRC scale and two patient-reported outcome measures (PROMs), BrAT and SPONEA. RESULTS: In total, 34 patients with 45 median and ulnar fascicle transfers were identified. This included 27 traumatic and seven atraumatic brachial plexus insults. Thirty patients had sufficient follow-up to be included in MRC analysis and 17 patients had sufficient follow-up to be included in PROM analysis. No significant differences were found between traumatic and atraumatic subgroups for median MRC, BrAT, or SPONEA scores. CONCLUSIONS: This study suggests that nerve transfers might be considered effective reconstructive options in atraumatic pathology and provides validation for further research on the subject.

Toward Fabrication of Devices Based on Graphene/Oxide Multilayers.

Owing to its high electrical conductivity, low density, and flexibility, graphene has great potential for use as a building block in a wide range of applications from nanoelectronics to biosensing and high-frequency devices. For many device applications, it is required to deposit dielectric materials on graphene at high temperatures and in ambient oxygen. This has been proven to be highly challenging because these conditions cause significant degradation in graphene. In this work, we investigate the degradation of graphene at elevated temperatures in an oxygen atmosphere and possible protection mechanisms to enable the growth of oxide thin films on graphene at higher temperatures. We show that coating graphene with self-assembled monolayers of hexamethyldisilazane (HMDS) prior to a high-temperature deposition can significantly reduce the damage induced. Furthermore, a graphene sample treated with HMDS displayed a weaker doping effect due to weak interaction with oxygen species than bare graphene, and a much slower rate of electrical resistance degradation was exhibited during annealing. Thus, it is a promising approach that could enable the deposition of metal oxide materials on graphene at high temperatures without significant degradation in graphene quality, which is critical for a wide range of applications.

Graphene Sensor Arrays for Rapid and Accurate Detection of Pancreatic Cancer Exosomes in Patients' Blood Plasma Samples.

Biosensors based on graphene field effect transistors (GFETs) have the potential to enable the development of point-of-care diagnostic tools for early stage disease detection. However, issues with reproducibility and manufacturing yields of graphene sensors, but also with Debye screening and unwanted detection of nonspecific species, have prevented the wider clinical use of graphene technology. Here, we demonstrate that our wafer-scalable GFETs array platform enables meaningful clinical results. As a case study of high clinical relevance, we demonstrate an accurate and robust portable GFET array biosensor platform for the detection of pancreatic ductal adenocarcinoma (PDAC) in patients' plasma through specific exosomes (GPC-1 expression) within 45 min. In order to facilitate reproducible detection in blood plasma, we optimized the analytical performance of GFET biosensors via the application of an internal control channel and the development of an optimized test protocol. Based on samples from 18 PDAC patients and 8 healthy controls, the GFET biosensor arrays could accurately discriminate between the two groups while being able to detect early cancer stages including stages 1 and 2. Furthermore, we confirmed the higher expression of GPC-1 and found that the concentration in PDAC plasma was on average more than 1 order of magnitude higher than in healthy samples. We found that these characteristics of GPC-1 cancerous exosomes are responsible for an increase in the number of target exosomes on the surface of graphene, leading to an improved signal response of the GFET biosensors. This GFET biosensor platform holds great promise for the development of an accurate tool for the rapid diagnosis of pancreatic cancer.

On-chip integrated graphene aptasensor with portable readout for fast and label-free COVID-19 detection in virus transport medium.

Graphene field-effect transistor (GFET) biosensors exhibit high sensitivity due to a large surface-to-volume ratio and the high sensitivity of the Fermi level to the presence of charged biomolecules near the surface. For most reported GFET biosensors, bulky external reference electrodes are used which prevent their full-scale chip integration and contribute to higher costs per test. In this study, GFET arrays with on-chip integrated liquid electrodes were employed for COVID-19 detection and functionalized with either antibody or aptamer to selectively bind the spike proteins of SARS-CoV-2. In the case of the aptamer-functionalized GFET (aptasensor, Apt-GFET), the limit-of-detection (LOD) achieved was about 103 particles per mL for virus-like particles (VLPs) in clinical transport medium, outperforming the Ab-GFET biosensor counterpart. In addition, the aptasensor achieved a LOD of 160 aM for COVID-19 neutralizing antibodies in serum. The sensors were found to be highly selective, fast (sample-to-result within minutes), and stable (low device-to-device signal variation; relative standard deviations below 0.5%). A home-built portable readout electronic unit was employed for simultaneous real-time measurements of 12 GFETs per chip. Our successful demonstration of a portable GFET biosensing platform has high potential for infectious disease detection and other health-care applications.

Detection of Glial Fibrillary Acidic Protein in Patient Plasma Using On-Chip Graphene Field-Effect Biosensors, in Comparison with ELISA and Single-Molecule Array.

Glial fibrillary acidic protein (GFAP) is a discriminative blood biomarker for many neurological diseases, such as traumatic brain injury. Detection of GFAP in buffer solutions using biosensors has been demonstrated, but accurate quantification of GFAP in patient samples has not been reported, yet in urgent need. Herein, we demonstrate a robust on-chip graphene field-effect transistor (GFET) biosensing method for sensitive and ultrafast detection of GFAP in patient plasma. Patients with moderate-severe traumatic brain injuries, defined by the Mayo classification, are recruited to provide plasma samples. The binding of target GFAP with the specific antibodies that are conjugated on a monolayer GFET device triggers the shift of its Dirac point, and this signal change is correlated with the GFAP concentration in the patient plasma. The limit of detection (LOD) values of 20 fg/mL (400 aM) in buffer solution and 231 fg/mL (4 fM) in patient plasma have been achieved using this approach. In parallel, for the first time, we compare our results to the state-of-the-art single-molecule array (Simoa) technology and the classic enzyme-linked immunosorbent assay (ELISA) for reference. The GFET biosensor shows competitive LOD to Simoa (1.18 pg/mL) and faster sample-to-result time (<15 min), and also it is cheaper and more user-friendly. In comparison to ELISA, GFET offers advantages of total detection time, detection sensitivity, and simplicity. This GFET biosensing platform holds high promise for the point-of-care diagnosis and monitoring of traumatic brain injury in GP surgeries and patient homes.

Enhancing Structural Properties and Performance of Graphene-Based Devices Using Self-Assembled HMDS Monolayers.

The performance of graphene devices is often limited by defects and impurities induced during device fabrication. Polymer residue left on the surface of graphene after photoresist processing can increase electron scattering and hinder electron transport. Furthermore, exposing graphene to plasma-based processing such as sputtering of metallization layers can increase the defect density in graphene and alter the device performance. Therefore, the preservation of the high-quality surface of graphene during thin-film deposition and device manufacturing is essential for many electronic applications. Here, we show that the use of self-assembled monolayers (SAMs) of hexamethyldisilazane (HMDS) as a buffer layer during the device fabrication of graphene can significantly reduce damage, improve the quality of graphene, and enhance device performance. The role of HMDS has been systematically investigated using surface analysis techniques and electrical measurements. The benefits of HMDS treatment include a significant reduction in defect density compared with as-treated graphene and more than a 2-fold reduction of contact resistance. This surface treatment is simple and offers a practical route for improving graphene device interfaces, which is important for the integration of graphene into functional devices such as electronics and sensor devices.

Carbon-Dot-Enhanced Graphene Field-Effect Transistors for Ultrasensitive Detection of Exosomes.

Graphene field-effect transistors (GFETs) are suitable building blocks for high-performance electrical biosensors, because graphene inherently exhibits a strong response to charged biomolecules on its surface. However, achieving ultralow limit-of-detection (LoD) is limited by sensor response time and screening effect. Herein, we demonstrate that the detection limit of GFET biosensors can be improved significantly by decorating the uncovered graphene sensor area with carbon dots (CDs). The developed CDs-GFET biosensors used for exosome detection exhibited higher sensitivity, faster response, and three orders of magnitude improvements in the LoD compared with nondecorated GFET biosensors. A LoD down to 100 particles/µL was achieved with CDs-GFET sensor for exosome detection with the capability for further improvements. The results were further supported by atomic force microscopy (AFM) and fluorescent microscopy measurements. The high-performance CDs-GFET biosensors will aid the development of an ultrahigh sensitivity biosensing platform based on graphene for rapid and early diagnosis of diseases.

Large-Area Electrodeposition of Few-Layer MoS2 on Graphene for 2D Material Heterostructures.

Heterostructures involving two-dimensional (2D) transition metal dichalcogenides and other materials such as graphene have a strong potential to be the fundamental building block of many electronic and optoelectronic applications. The integration and scalable fabrication of such heterostructures are of the essence in unleashing the potential of these materials in new technologies. For the first time, we demonstrate the growth of few-layer MoS2 films on graphene via nonaqueous electrodeposition. Through methods such as scanning and transmission electron microscopy, atomic force microscopy, Raman spectroscopy, energy- and wavelength-dispersive X-ray spectroscopies, and X-ray photoelectron spectroscopy, we show that this deposition method can produce large-area MoS2 films with high quality and uniformity over graphene. We reveal the potential of these heterostructures by measuring the photoinduced current through the film. These results pave the way toward developing the electrodeposition method for the large-scale growth of heterostructures consisting of varying 2D materials for many applications.

Facile biosensors for rapid detection of COVID-19.

Currently the world is being challenged by a public health emergency caused by the coronavirus pandemic (COVID-19). Extensive efforts in testing for coronavirus infection, combined with isolating infected cases and quarantining those in contact, have proven successful in bringing the epidemic under control. Rapid and facile screening of this disease is in high demand. This review summarises recent advances in strategies reported by international researchers and engineers concerning how to tackle COVID-19 via rapid testing, mainly through nucleic acid- and antibody- testing. The roles of biosensors as powerful analytical tools are emphasized for the detection of viral RNAs, surface antigens, whole viral particles, antibodies and other potential biomarkers in human specimen. We critically review in depth newly developed biosensing methods especially for in-field and point-of-care detection of SARS-CoV-2. Additionally, this review describes possible future strategies for virus rapid detection. It helps researchers working on novel sensor technologies to tailor their technologies in a way to address the challenge for effective detection of COVID-19.

Medial Patellofemoral Ligament Reconstruction in Traumatic Patellar Dislocation without Patellar Fixation.

Acute traumatic patellar dislocation is a common injury, and spontaneous reduction may occur at the time of injury or may be reduced at the field of the accident by someone. It may be associated with osteochondral fractures and rupture of medial patellar stabilizers leading to recurrent patellar instability. The aim of this prospective study was to evaluate the outcomes of medial patellofemoral (PF) ligament (MPFL) reconstruction in recurrent traumatic patellar dislocation. Forty-five patients presented with PF instability as a result of traumatic rupture MPFL with normal patellar tracking underwent MPFL reconstruction without patellar fixation hardware through two parallel transpatellar tunnels and one screw in femoral tunnel. All patients were evaluated clinically preoperatively and at a minimum follow-up of 24 months, and International Knee Documentation Committee (IKDC) and Kujala scores were used to assess the clinical results. All patients were available for evaluation at a minimum of 24 months (up to 36 months). The mean age of these patients at the time of surgery was 22.82 years (range: 18-34 years). All patients gave history of trauma of their knees. Mean IKDC scale showed significant improvement as it rose from 47.17 preoperatively to 77.94 postoperatively, and mean Kujala score rose from 53.88 preoperatively to 86.24 postoperatively (p < 0.001). No recurrence of dislocation was recorded. Only three patients had mild atrophy of thigh and one patient had some difficulty in jumping. Reconstruction of MPFL by this method provides good clinical result in the treatment of PF instability by using autologous graft (semitendinosus and gracilis). Less hardware were used with less complications.

Chemically Functionalised Graphene FET Biosensor for the Label-free Sensing of Exosomes.

A graphene field-effect transistor (gFET) was non-covalently functionalised with 1-pyrenebutyric acid N-hydroxysuccinimide ester and conjugated with anti-CD63 antibodies for the label-free detection of exosomes. Using a microfluidic channel, part of a graphene film was exposed to solution. The change in electrical properties of the exposed graphene created an additional minimum alongside the original Dirac point in the drain-source current (Ids) - back-gate voltage (Vg) curve. When phosphate buffered saline (PBS) was present in the channel, the additional minimum was present at a Vg lower than the original Dirac point and shifted with time when exosomes were introduced into the channel. This shift of the minimum from the PBS reference point reached saturation after 30 minutes and was observed for multiple exosome concentrations. Upon conjugation with an isotype control, sensor response to the highest concentration of exosomes was negligible in comparison to that with anti-CD63 antibody, indicating that the functionalised gFET can specifically detect exosomes at least down to 0.1 µg/mL and is sensitive to concentration. Such a gFET biosensor has not been used before for exosome sensing and could be an effective tool for the liquid-biopsy detection of exosomes as biomarkers for early-stage identification of diseases such as cancer.

Tear drop-free anterolateral thigh flap, a versatile design for lower limb reconstruction after trauma.

BACKGROUND: In lower limb reconstruction the cosmetic outcome is influenced by the contouring of the flap at the recipient site as well as by the donor site closure. It is also important to minimise compression of the flap pedicle. We discuss the outcomes of a versatile ALT flap design that allows freedom in skin paddle tailoring without elongating the scar, reduction of the tension over the pedicle and improved cosmetic results of both donor and recipient sites. METHODS: Between January 2009 and October 2015, 27 patients underwent reconstruction using tear drop ALTs. The age ranged between 20 and 89 years. Seventeen were elective procedures and 10 were urgent. The locations of the defects were: knee (1 case), achilles tendon (2 cases), os calcis (1 case), lateral malleolus (1 case), fibula (3 cases), tibia (6 cases), tibia/fibula (5 cases), and ankle (8 cases). The sizes of the defects ranged from 4 × 3 cm to 9 × 7 cm. RESULTS: The size of the flap ranged from 6 × 4 cm to 11 × 7 cm. One venous congestion and a wound dehiscence occurred, no flap loss. Two defatting procedures were performed. The mean follow-up was 16.44 months. Final outcomes showed good functional and cosmetic results in both the donor and recipient sites. CONCLUSIONS: The tear drop ALT is a useful tool in lower limb reconstruction allowing to improve skin paddle tailoring without elongating the donor site scar. It allows minimal tension over the pedicle while optimizing the contour of both the donor and recipient sites.

Anatomic Reconstruction of the Anterior Cruciate Ligament of the Knee With or Without Reconstruction of the Anterolateral Ligament: A Randomized Clinical Trial.

BACKGROUND: Rotational instability of the knee remains an issue after anterior cruciate ligament (ACL) reconstruction. Hypothesis/Purpose: The purpose was to evaluate the subjective and objective outcomes of combined reconstruction of the ACL and anterolateral ligament (ALL) of the knee. The hypothesis was that favorable outcomes can be achieved with this surgical procedure compared with isolated anatomic reconstruction of the ACL. STUDY DESIGN: Randomized controlled trial; Level of evidence, 2. METHODS: One hundred ten patients with a unilateral ACL injury and high-grade pivot shift were randomly assigned to undergo either combined ACL and ALL reconstruction (group A) or isolated ACL reconstruction (group B). Preoperative and postoperative evaluations of the patients were conducted by obtaining history details, recording physical examination findings, measuring knee laxity using the KT-1000 arthrometer, and using validated outcome scores for the knee. P < .05 was considered as the cut-off level of statistical significance. The Fisher exact and Mann-Whitney U tests were used to assess statistical significance. RESULTS: At a mean follow-up of 27 months, 53 and 50 patients in groups A and B, respectively, were available for analysis. No statistically different outcomes were found between the 2 groups except for the KT-1000 arthrometer values. The median KT-1000 arthrometer result for combined ACL and ALL reconstruction was 1.3 mm, while the median result for isolated ACL reconstruction was 1.8 mm ( P < .001). None of the patients (n = 0; 0.0%) who underwent combined ACL and ALL reconstruction had anterior translation of greater than 5 mm at maximum pulling strength compared with their normal knees at final follow-up. On the other hand, 3 (6.0%) patients who underwent isolated ACL reconstruction had anterior translation of more than 5 mm. No serious complications were found in both groups. CONCLUSION: Combined ACL and ALL reconstruction was found to be effective in improving subjective and objective outcomes. Nevertheless, these findings were not significantly superior to isolated ACL reconstruction except for the instrumented knee laxity testing results. This might indicate that ALL reconstruction should not be performed routinely for patients undergoing ACL reconstruction.

Love-mode surface acoustic wave devices based on multilayers of TeO2/ZnO(112¯0)/Si(100) with high sensitivity and temperature stability.

A multilayer structure of TeO2/interdigital transducers (IDTs)/ZnO(112¯0)/Si(100) was proposed and investigated to achieve both high sensitivity and temperature-stability for bio-sensing applications. Dispersions of phase velocities, electromechanical coupling coefficients K2, temperature coefficient of delay (TCD) and sensitivity in the multilayer structures were simulated as functions of normalized thicknesses of ZnO (hZnO/λ) and TeO2 (hTeO2/λ) films. The fundamental mode of Love mode (LM) - surface acoustic wave (SAW) shows a larger value of K2 and higher sensitivity compared with those of the first mode. TeO2 film with a positive TCD not only compensates the temperature effect induced due to the negative TCD of ZnO(112¯0)/Si(100), but also enhances the sensitivity of the love mode device. The optimal normalized thickness ratios were identified to be hTeO2/λ=0.021 and hZnO/λ=0.304, and the devices with such structures can which generate a normalized sensitivity of -1.04×10-3m3/kg, a TCD of 0.009ppm/°C, and a K2 value of 2.76%.

Electroless Nickel Deposition: An Alternative for Graphene Contacting.

We report the first investigation into the potential of electroless nickel deposition to form ohmic contacts on single layer graphene. To minimize the contact resistance on graphene, a statistical model was used to improve metal purity, surface roughness, and coverage of the deposited film by controlling the nickel bath parameters (pH and temperature). The metalized graphene layers were patterned using photolithography and contacts deposited at temperatures as low as 60 °C. The contact resistance was 215 ± 23 Ω over a contact area of 200 µm × 200 µm, which improved upon rapid annealing to 107 ± 9 Ω. This method shows promise toward low-cost and large-scale graphene integration into functional devices such as flexible sensors and printed electronics.