Over-the-Top Double-Bundle Revision Anterior Cruciate Ligament Reconstruction Technique With Hybrid Hamstring Tendon Autograft-Allograft and Associated Lateral Extra-articular Tenodesis.

Revision anterior cruciate ligament (ACL) presents many technical challenges that are not commonly seen in primary ACL reconstruction. The purpose of this article is to describe an alternative technique consisting of over-the-top double-bundle ACL revision combined with lateral extra-articular tenodesis using hybrid hamstring tendon autograft-allograft. This technique provides a valid treatment option in ACL revision surgery.

RETRACTED: Chen et al. Clinical Effect of Arthroscopic Resection of Extra-Articular Knee Osteochondroma. J. Clin. Med. 2023, 12, 52.

Following publication, the authors of "Clinical Effect of Arthroscopic Resection of Extra-Articular Knee Osteochondroma" by Chen et al. [...].

The pattern of collagen production may contribute to the gluteal muscle contracture pathogenic process.

INTRODUCTION: Arthroscopic release is now the gold standard globally for gluteal muscle contracture (GMC) treatment. However, some patients fail to improve after the first operation and are forced to undergo a second operation. This study explores the essential role collagen fibers may play in muscle contracture in GMC. METHODS: From February 2010 to May 2018, 1041 hips of 543 GMC patients underwent arthroscopic release. Among them, 498 (91.7%) patients had bilateral GMC and were admitted to the retrospective cohort study. Pathological testing and type III collagen testing were used in contracture tissue studies. Single-cell RNA-sequencing analysis was applied to explore the role of fibroblasts in muscle repair. RESULTS: Compared with GMC II patients, GMC III patients displayed higher clinical symptoms (P < 0.05). Six weeks after the surgery, the patients in GMC II had a lower prominent hip snap rate, higher JOA score, and better hip range of motion (P < 0.05). Compared with normal muscle tissue, contracture-affected tissue tended to have more type III collagen and form shorter fibers. Recurrent GMC patients seemed to have a higher type III collagen ratio (P < 0.05). In contrast to normally repairable muscle defects, fibroblasts in non-repairable defects were shown to downregulate collagen-related pathways at the early and late stages of tissue repair. DISCUSSION: This study describes the arthroscopic release of GMC. Study findings include the suggestion that the collagen secretion function of fibroblasts and collagen pattern might influence the muscle repair ability and be further involved in the GMC pathogenic process.

Clinical Effect of Arthroscopic Resection of Extra-Articular Knee Osteochondroma.

Objective: The aim of this study was to investigate clinical outcomes of arthroscopic resection of extraarticular knee osteochondroma. Methods: A retrospective analysis was performed in 74 patients with extra-articular knee osteochondroma treated by arthroscopic resection between August 2011 and August 2021, including 43 males and 31 females. Overall, 26 Distal femur cases and 48 proximal tibia cases were involved, with an average age of 31.7 ± 11.3 (11−57) years. Preoperative routine knee X-ray, CT, and MRI were performed before the operation. The Lysholm knee score, International Knee Documentation Committee (IKDC) score, Tegner knee motor function score, and visual analogue scale (VAS) were used to evaluate symptoms and functions before surgery and 3, 6, 12, and ≥24 months after surgery. Results: The average course of disease was (7.9 ± 3.7) months (range, 3−14 months) in 74 patients. The average follow-up was (22.6 ± 6.4) months (range, 10−37 months). There were no cases of vascular or nerve injury or wound infection. Compared with the preoperative function, the average scores of VAS, Lysholm, IKDC, and Tegner joint motor function decreased or increased significantly compared with the last follow-up (3.6 ± 1.1 vs. 0.1 ± 0.02, 44.5 ± 2.3 vs. 91.3 ± 4.9, 53.7 ± 2.6 vs. 94.2 ± 5.1, 4.6 ± 1.2 vs. 9.4 ± 1.4, p < 0.001). There was no recurrence or metastasis during the follow up. Conclusions: With the advantages of less trauma, high precision, less pain, and rapid recovery, arthroscopic resection of extra-articular knee osteochondroma can significantly improve the function of knee. It can be gradually extended to the treatment of other benign bone tumors.

A Nomogram for Predicting the Residual Back Pain after Percutaneous Vertebroplasty for Osteoporotic Vertebral Compression Fractures.

OBJECTIVE: Current findings suggest that percutaneous vertebroplasty (PVP) is a suitable therapeutic approach for osteoporotic vertebral compression fractures (OVCFs). However, a significant minority of patients still experience residual back pain after PVP. The present retrospective study was designed to determine the risk factors for residual back pain after PVP and provides a nomogram for predicting the residual back pain after PVP. METHODS: We retrospectively reviewed the medical records of patients with single-segment OVCFs who underwent bilateral percutaneous vertebroplasty. Patients were divided into group N and group R according to the postoperative VAS score. Group R is described as the VAS score of residual back pain ≥ 4. Pre- and postoperative factors that may affect back pain relief were evaluated between two groups. Univariate and multivariate logistic regression analysis were performed to identify risk factors affecting residual back pain after PVP. We provided a nomogram for predicting the residual back pain and used the receiver operating characteristic curve (ROC), concordance index (C-index), calibration curve, and decision curve analyses (DCA) to evaluate the prognostic performance. RESULTS: Among 268 patients treated with PVP, 37 (13.81%) patients were classified postoperative residual back pain. The results of the multivariate logistical regression analysis showed that the presence of an intravertebral vacuum cleft (IVC) (OR 3.790, P=0.026), posterior fascia oedema (OR 3.965, P=0.022), severe paraspinal muscle degeneration (OR 5.804, P=0.01; OR 13.767, P < 0.001), and blocky cement distribution (OR 2.225, P=0.041) were independent risk factors for residual back pain after PVP. The AUC value was 0.780, suggesting that the predictive ability was excellent. The prediction nomogram presented good discrimination, with a C-index of 0.774 (0.696∼0.852) and was validated to be 0.752 through bootstrapping validation. The calibration curve of the nomogram demonstrated a good consistency between the probabilities predicted by the nomogram and the actual probabilities. The nomogram showed net benefits in the range from 0.06 to 0.66 in DCA. CONCLUSIONS: The presence of IVC, posterior fascia oedema, blocky cement distribution, and severe paraspinal muscle degeneration were significant risk factors for residual back pain after PVP for OVCFs. Patients with OVCFs after PVP who have these risk factors should be carefully monitored for the possible development of residual back pain. We provide a nomogram for predicting the residual back pain after PVP.

[Interpretation of 2020 American Academy of Orthopaedic Surgeons (AAOS) on the Management of Glenohumeral Joint Osteoarthritis Evidence-Based Clinical Practice Guideline].

The 2020 Management of Glenohumeral Joint Osteoarthritis Evidence-Based Clinical Practice Guideline which was prepared by the American Academy of Orthopaedic Surgeons (AAOS) were publicated on October 2020. The guideline involves the following 8 chapters: drug therapy and injectable biologics, physical therapy and non-surgical treatments, radiographs, prognostic factors, surgical treatments, intraoperative hemostasis measure (tranexamic acid), management of supraspinatus tears, multimodal pain management and discharge. In this paper, the guideline is interpreted to provide cutting-edge information for domestic glenohumeral joint osteoarthritis researchers.

Deep Learning-Based Magnetic Resonance Imaging Image Features for Diagnosis of Anterior Cruciate Ligament Injury.

To study and explore the adoption value of magnetic resonance imaging (MRI) in the diagnosis of anterior cruciate ligament (ACL) injuries, a multimodal feature fusion model based on deep learning was proposed for MRI diagnosis. After the related performance of the proposed algorithm was evaluated, it was utilized in the diagnosis of knee joint injuries. Thirty patients with knee joint injuries who came to our hospital for treatment were selected, and all patients were diagnosed with MRI based on deep learning multimodal feature fusion model (MRI group) and arthroscopy (arthroscopy group). The results showed that deep learning-based MRI sagittal plane detection had a great advantage and a high accuracy of 96.28% in the prediction task of ACL tearing. The sensitivity, specificity, and accuracy of MRI in the diagnosis of ACL injury was 96.78%, 90.62%, and 92.17%, respectively, and there was no considerable difference in contrast to the results obtained through arthroscopy (P > 0.05). The positive rate of acute ACL patients with bone contusion and medial collateral ligament injury was substantially superior to that of chronic injury. Moreover, the incidence of chronic injury ACL injury with meniscus tear and cartilage injury was notably higher than that of acute injury, with remarkable differences (P < 0.05). In summary, MRI images based on deep learning improved the sensitivity, specificity, and accuracy of ACL injury diagnosis and can accurately determined the type of ACL injury. In addition, it can provide reference information for clinical treatment plan selection and surgery and can be applied and promoted in clinical diagnosis.

miR-146a promoted breast cancer proliferation and invasion by regulating NM23-H1.

The study aimed to investigate the regulatory effect of miR-146a in proliferation, invasion and migration of breast cancer and its possible mechanism via NM23-H1. The expression levels of miR-146a in breast cancer with different pathological classification were significantly increased, while the expression levels of NM23-H1 were significantly decreased, which were closely correlated. Double luciferase reporter gene was used to verify the target regulatory relationship between miR-146 and NM23-H1 on a human breast cancer cell line. miR-146a was closely related to the proliferation and metastasis of breast cancer. miR-146a also promoted the growth of breast cancer in vivo via targeting NM23-H1. In conclusion, miR-146 can promote the proliferation and invasion of breast cancer by targeting NM23-H1.

Allogenic Tendon-Autologous Cartilage Cells Transplantation Enhances Adhesive/Growth Ability and Promotes Chondrogenesis in a Rabbit Model of Glenoid Labrum Damage.

BACKGROUND Glenoid labrum injury of the shoulder commonly occurs in athletes, especially those who perform throwing motions. This study investigated the effects of the established allogenic tendon-autologous cartilage cells reconstruction approach in a rabbit model of glenoid labrum damage. MATERIAL AND METHODS The allogenic tendons were isolated and extracted using the chemical extraction method. Cartilage cells were isolated from New Zealand rabbits and identified by detecting type II collagenase. The allogenic tendon-autologous cartilage cells were transplanted to the damaged glenoid labrum. HE staining was used to observe inflammatory cells, Masson staining was used to observe muscle fibers, and scanning electron microscopy (SEM) was used to assess antigenicity of tendon tissues. PSA and AB staining were used to examine neutral protein mucopolysaccharide and acidic protein mucopolysaccharide, respectively. We assessed cartilage cell growth in autologous cartilage cells combined with allogenic tendon transplanted tissues. RESULTS Allogenic tendons were well prepared using chemical extraction method due to use of HE staining, Masson staining, and SEM. TGF-ß1 treatment induced cartilage cell formation and triggered expression of acidic and neutral protein mucopolysaccharides. HE staining, Masson staining, PAS staining, and AB staining methods showed that autologous cartilage cells combined with allogenic tendon transplanted tissues had better growth of cartilage cells. CONCLUSIONS This study establishes the allogenic tendon-autologous cartilage cells reconstruction and transplantation approach and illustrated higher adhesive ability and growth ability, and better chondrogenesis in a rabbit model of glenoid labrum damage.

Arthroscopic subscapularis augmentation combined with capsulolabral reconstruction is safe and reliable.

PURPOSE: The study aimed to compare modified arthroscopic subscapularis augmentation (MASA) with tenodesis of the upper third of the subscapularis tendon using a tendon combined with capsulolabral reconstruction (Group A) or Bankart repair (Group B) for recurrent anterior shoulder instability (RASI). METHODS: A retrospective series of 49 patients underwent primary surgery for RASI with glenoid bone loss (GBL) < 25%. Outcomes included the Oxford Shoulder Instability Score (OSIS), Visual Analogue Scale (VAS) score, Rowe score, and American Shoulder and Elbow Surgeons (ASES) functional outcome scale score. Recurrent instability, sports activity level, and range of motion (ROM) were also analysed. RESULTS: No significant differences were observed at baseline. Forty-six patients were available for more than 2 years of follow-up. At the last follow-up after surgery, the patients in both groups had experienced significant improvements in all outcome scores (P < 0.05 for all), and obvious decreases in forward flexion and external rotation were noted in both groups (P < 0.05 for all). Group A had superior ASES scores, VAS scores, and OSISs (P < 0.05) but did not experience significant differences in either the Rowe score or ROM compared to Group B. Group A had lower rates of recurrent instability and superior outcomes for the return to sports activities. One patient in Group A had subluxation, and 4 patients in Group B had dislocation or subluxation. No patients in either group experienced neurovascular injury, joint stiffness, or surgical wound infection. CONCLUSION: For RASI with GBL < 25%, MASA with tenodesis of the upper third of the subscapularis tendon using a tendon combined with capsulolabral reconstruction was a safe technique that produced better outcomes in terms of ASES scores, VAS scores, OSISs, the return to sports, and postoperative recurrent instability and did not decrease the ROM compared to that achieved by arthroscopic Bankart repair. LEVEL OF EVIDENCE: III.

The characteristic arthroscopic 'eyelid- turnup' sign indicated for partial-thickness longitudinal medial meniscus tear.

BACKGROUND: Medial posterior horn meniscal tear is difficult to be visualized in full view during arthroscopy and is occasionally undetected when the superior surface seems intact. OBJECTIVE: The purpose of this study is to describe a characteristic arthroscopic sign indicating the occult partial-thickness longitudinal medial meniscus tear extending only to the inferior articular surface. METHODS: This study was a retrospective analysis of available arthroscopic knee surgery between January 2016 and December 2017. The videos were studied and data was recorded for the number of cases showing the presence of 'eyelid-turnup' sign and coexisting partial-thickness medial meniscus tear. Sensitivity and positive predictive value of the sign were calculated. RESULTS: Of all the 491 videos of medial meniscal tear available for review, partial-thickness longitudinal medial meniscus was torn in 26 cases. Six out of 26 patients could be diagnosed with partial-thickness longitudinal tear under direct vision. Of the other 20 patients which could not be diagnosed under direct vision during arthroscopy until the tear was pressed by a probe, 17 patients were diagnosed by the positive 'eyelid-turnup' sign. The other 3 patients showed negative 'eyelid-turnup' sign and were then diagnosed by the hints of preoperative MRI and intra-operative exploration. The sensitivity of the sign was 85%; the positive predictive value was 89.5%. CONCLUSIONS: The 'eyelid-turnup' sign of meniscus pressed by a probe at arthroscopy is a characteristic indicator for occult inferior partial-thickness longitudinal tears of midbody and posterior horn. Early identification of this special sign may help reduce the likelihood that the occult partial-thickness longitudinal tear will be missed during arthroscopy.

Clinical and radiologic outcomes after a modified bone plug technique with anatomical meniscal root reinsertion for meniscal allograft transplantation and a minimum 18-month follow-up.

OBJECTIVE: To evaluate the clinical and radiologic outcomes of meniscal allograft transplantation (MAT) using a modified bone plug technique. METHODS: We conducted a retrospective single-center study of 73 patients who underwent MAT between January 2007 and December 2013. The International Knee Documentation Committee (IKDC) score, Lysholm score, Tegner score, visual analogue scale (VAS), and physical examinations were retrospectively reviewed to measure clinical outcomes after MAT, and questionnaires regarding activity and factors were analyzed. Magnetic resonance imaging (MRI) was used to assess the cartilage status and meniscal extrusion. RESULTS: The mean follow-up was 37 months for 61 patients (65 knees), and 12 patients were lost to follow-up. The mean meniscal extrusion was 3.39 ± 0.90 mm, the relative percentage of extrusion (RPE) was 34.82% ± 12.71%, and arthrosis progression was observed in 8 of 61 cases (13.1%). The mean results for VAS, IKDC, and Lysholm scores were significantly improved after MAT (P < 0.05), but there were no significant differences in the range of motion or Tegner score (P > 0.05). Thirty-eight (62.3%) patients were able to return to their previous level of activity, and 23 (37.7%) patients reached a mean 76.7% of the previous level of activity. Of the 23 patients reporting a decrease in activity, 10 reported a fear of reinjury as the primary factor limiting activity. The patient satisfaction rate in the study was 78.7%. CONCLUSION: Our modified bone plug method with anatomical meniscal root reinsertion was an effective surgical method, and the majority of active patients with meniscal disorders returned to preinjury levels of activity.

Baicalein Accelerates Tendon-Bone Healing via Activation of Wnt/ß-Catenin Signaling Pathway in Rats.

BACKGROUND: Tendon-bone healing is a reconstructive procedure which requires a tendon graft healing to a bone tunnel or to the surface of bone after the junction injury between tendon, ligament, and bone. The surgical reattachment of tendon to bone often fails due to regeneration failure of the specialized tendon-bone junction. MATERIALS AND METHODS: An extra-articular tendon-bone healing rat model was established to discuss the effect of the baicalein 10 mg/(kg·d) in accelerating tendon-bone healing progress. Also, tendon-derived stem cells (TDSCs) were treated with various concentrations of baicalein or dickkopf-1 (DKK-1) to stimulate differentiation for 14 days. RESULTS: In vivo, tendon-bone healing strength of experiment group was obviously stronger than the control group in 3 weeks as well as in 6 weeks. And there were more mature fibroblasts, more Sharpey fibers, and larger new bone formation area treated intragastrically with baicalein compared with rats that were treated with vehicle for 3 weeks and 6 weeks. In vitro, after induction for 14 days, the expressions of osteoblast differentiation markers, that is, alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2), osteocalcin (OCN), osterix (OSX), and collagen I, were upregulated and Wnt/ß-catenin signaling pathway was enhanced in TDSCs. The effect of DKK-1 significantly reduced the effect of baicalein on the osteogenic differentiation. CONCLUSION: These data suggest that baicalein may stimulate TDSCs osteogenic differentiation via activation of Wnt/ß-catenin signaling pathway to accelerate tendon-bone healing.

Microfluidic isolation of platelet-covered circulating tumor cells.

The interplay between platelets and tumor cells is known to play important roles in metastasis by enhancing tumor cell survival, tumor-vascular interactions, and escape from immune surveillance. However, platelet-covered circulating tumor cells (CTC) are extremely difficult to isolate due to masking or downregulation of surface epitopes. Here we describe a microfluidic platform that takes advantage of the satellite platelets on the surface of these "stealth" CTCs as a ubiquitous surface marker for isolation. Compared to conventional CTC enrichment techniques which rely on known surface markers expressed by tumor cells, platelet-targeted isolation is generally applicable to CTCs of both epithelial and mesenchymal phenotypes. Our approach first depletes unbound, free platelets by means of hydrodynamic size-based sorting, followed by immunoaffinity-based capture of platelet-covered CTCs using a herringbone micromixing device. This method enabled the reliable isolation of CTCs from 66% of lung and 60% of breast cancer (both epithelial) patient samples, as well as in 83% of melanoma (mesenchymal) samples. Interestingly, we observed special populations of CTCs that were extensively covered by platelets, as well as CTC-leukocyte clusters. Because these cloaked CTCs often escape conventional positive and negative isolation mechanisms, further characterization of these cells may uncover important yet overlooked biological information in blood-borne metastasis and cancer immunology.

Arthroscopic revision release of gluteal muscle contracture after failed primary open surgery.

PURPOSE: The treatment of gluteal muscle contracture (GMC) after failed primary open release surgery has rarely been reported in the literature. GMC is a troublesome health problem in some developing countries, and it can result in the limitation of patients' hip function, leading to the development of inferiority complexes. The aim of this study is to evaluate the effect of arthroscopic revision surgery after failed primary open release on patients with GMC. METHODS: A total of 278 hips of 140 patients who underwent arthroscopic revision procedures after failed primary open surgeries were gathered from the department files. All patients were treated using a "three-step" arthroscopic release procedure by the same surgeon group. RESULTS: The mean follow-up for the 136 patients was 38.9 months. There was significant difference (P < 0.05) between the patients' mean post-revision and pre-operative results on the Harris scoring system. Unreleased contracture tissues that needed revision operations included the gluteus maximus, tensor fasciae latae muscle, and gluteus medius in all patients, and the gluteus minimus and hip capsule in 11.0% and 8.1% of patients, respectively. Short-term complications included subcutaneous bruising of the abdomen in 11 patients, extensive ecchymosis in the lateral thigh in 12 patients, and a transient reduction of muscle strength in all patients. No complications involving postoperative incision infection, nerve and blood vessel damage, or positive Trendelenburg sign occurred. Symptoms of hip snapping and limitation of range of motion (ROM), combined with a positive Trendelenburg sign in two patients after the primary open surgery, were all resolved except for the Trendelenburg sign through arthroscopic revision release. The overall satisfaction rate of the revision operations was 90.4%. CONCLUSION: The three-step arthroscopic release procedure is effective for failed primary open GMC surgeries as shown by improved post-operative function and patient satisfaction regardless of which primary procedure was performed.

Characteristic arthroscopic signs of cartilage injuries indicating concomitant occult medial meniscal peripheral tears of posterior horn.

BACKGROUND: Medial posterior horn meniscal tear is difficult to visualise during arthroscopy and is occasionally undetected by preoperative magnetic resonance imaging (MRI). Consequently, attention should be paid to performing a thorough examination and to some characteristic signs that indicate occult meniscal tear. The purpose of this study was to assess an indicative correlation between arthroscopic features of cartilage injury and a concomitant occult meniscal tear. METHODS: We performed a retrospective clinical and radiographic study of a consecutive series of patients between January 2013 and December 2014. Of 1,596 patients, all 78 with wave-like chondral injury of the medial femoral condyle diagnosed at arthroscopy were included in the study. The occurrence, pattern, location and concomitant pathology of medial meniscal injury were analysed. RESULTS: The characteristic wave sign associated with chondral injury in the medial femoral condyle was detected by MRI preoperatively in two cases only; all others were discovered intraoperatively at arthroscopy. Cartilage injury was rated as Outerbridge type II in 53 patients, type III in 24, and type IV in one. Wave sign defects were all characterised by their transverse orientation in the load-bearing femoral condyle. The occult longitudinal peripheral meniscus tear of the posterior horn was seen in all patients with a positive wave sign visualised under arthroscopy. The wave sign was positively correlated with medial peripheral meniscal injury of the posterior horn (P < 0.01). CONCLUSION: Wave sign chondral injury in the medial femoral condyle seen at arthroscopy is a characteristic indicator for concomitant occult medial longitudinal peripheral meniscus tears of the posterior horn. LEVEL OF EVIDENCE: Case series, Level IV.

[ANATOMICAL RESEARCH OF TIBIAL INSERTION OF ANTERIOR CRUCIATE LIGAMENT IN CHINESE ADULTS].

OBJECTIVE: To observe the anatomical morphology of the tibial insertion of the anterior cruciate ligament (ACL) in Chinese adults so as to offer theoretical guidance for ACL reconstruction and meniscus transplantation. METHODS: Fifteen adult cadaveric knees (8 left knees and 7 right knees) were dissected, including 10 males and 5 females, with an age ranged from 25 to 47 years (mean, 32.4 years). All knees were generally observed through standard medial parapatellar approaches, then the ACL midsubstance and the tibial insertion (direct and indirect insertions) were anatomically measured. RESULTS: In all specimens, the ACL was flat with a lot of fine fibers. The anteromedial bundle and posterolateral bundle could be observed in 13 of 15 knees. However, no obvious bundles were found in 2 knees. The arc-shaped tibial direct insertion started at the medial tibial eminence and ended at the anterior horn of the lateral meniscus. The width of the arc was (11.2 ± 2.4) mm; the thickness was (3.0 ± 0.3) mm; and the cross-sectional area was (28.8 ± 7.8) mm2. And the left-right diameter of the whole insertion was (9.5 ± 1.8) mm; anteroposterior diameter was (11.9 ± 0.6) mm; and the cross-sectional area was (117.8 ± 12.5) mm2. The width of the anterior horn of lateral meniscus was (12.3 ± 2.0) mm. The anterior horn of lateral meniscus was surrounded by arc-shaped direct insertion in the middle, and its fibers were partly intertwined with indirect insertion of ACL. CONCLUSION: Anatomical ACL reconstruction may therefore require a arc-shaped tibial footprint. There are overlap covering relationship between the attachment location of anterior horn of the lateral meniscus and tibial insertion of ACL. It should pay more attention to protecting tibial insertion of ACL in lateral meniscus transplantation.

General strategy for biodetection in high ionic strength solutions using transistor-based nanoelectronic sensors.

Transistor-based nanoelectronic sensors are capable of label-free real-time chemical and biological detection with high sensitivity and spatial resolution, although the short Debye screening length in high ionic strength solutions has made difficult applications relevant to physiological conditions. Here, we describe a new and general strategy to overcome this challenge for field-effect transistor (FET) sensors that involves incorporating a porous and biomolecule permeable polymer layer on the FET sensor. This polymer layer increases the effective screening length in the region immediately adjacent to the device surface and thereby enables detection of biomolecules in high ionic strength solutions in real-time. Studies of silicon nanowire field-effect transistors with additional polyethylene glycol (PEG) modification show that prostate specific antigen (PSA) can be readily detected in solutions with phosphate buffer (PB) concentrations as high as 150 mM, while similar devices without PEG modification only exhibit detectable signals for concentrations ≤10 mM. Concentration-dependent measurements exhibited real-time detection of PSA with a sensitivity of at least 10 nM in 100 mM PB with linear response up to the highest (1000 nM) PSA concentrations tested. The current work represents an important step toward general application of transistor-based nanoelectronic detectors for biochemical sensing in physiological environments and is expected to open up exciting opportunities for in vitro and in vivo biological sensing relevant to basic biology research through medicine.

Controlled synthesis of millimeter-long silicon nanowires with uniform electronic properties.

We report the nanocluster-catalyzed growth of ultralong and highly uniform single-crystalline silicon nanowires (SiNWs) with millimeter-scale lengths and aspect ratios up to approximately 100,000. The average SiNW growth rate using disilane (Si 2H 6) at 400 degrees C was 31 microm/min, while the growth rate determined for silane (SiH 4) reactant under similar growth conditions was 130 times lower. Transmission electron microscopy studies of millimeter-long SiNWs with diameters of 20-80 nm show that the nanowires grow preferentially along the 110 direction independent of diameter. In addition, ultralong SiNWs were used as building blocks to fabricate one-dimensional arrays of field-effect transistors (FETs) consisting of approximately 100 independent devices per nanowire. Significantly, electrical transport measurements demonstrated that the millimeter-long SiNWs had uniform electrical properties along the entire length of wires, and each device can behave as a reliable FET with an on-state current, threshold voltage, and transconductance values (average +/-1 standard deviation) of 1.8 +/- 0.3 microA, 6.0 +/- 1.1 V, 210 +/- 60 nS, respectively. Electronically uniform millimeter-long SiNWs were also functionalized with monoclonal antibody receptors and used to demonstrate multiplexed detection of cancer marker proteins with a single nanowire. The synthesis of structurally and electronically uniform ultralong SiNWs may open up new opportunities for integrated nanoelectronics and could serve as unique building blocks linking integrated structures from the nanometer through millimeter length scales.