A multicenter, randomized controlled trial comparing a second-generation uncemented trabecular metal-backed vs. cemented polyethylene glenoid component in total shoulder arthroplasty: 5-year results.

BACKGROUND: Previously, we reported early (2-year) findings from a randomized controlled trial comparing a second-generation uncemented trabecular metal-backed (TM) glenoid vs. cemented polyethylene glenoid (POLY) in patients undergoing a total shoulder arthroplasty. The purpose of the current study is to report disease-specific quality of life, clinical, patient-reported, and radiographic outcomes at midterm (5-year) from this trial. METHODS: Five surgeons from 3 centers participated. Patients 18-79 years with a primary diagnosis of glenohumeral osteoarthritis were screened for eligibility. Randomization to an uncemented TM or cemented POLY glenoid was performed intra-operatively after adequate bone stock was confirmed. Study intervals were baseline, 2- and 5-year postoperative. The primary outcome was the Western Ontario Osteoarthritis Shoulder (WOOS) quality of life score. Secondary outcomes included the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, EuroQol-5 Dimensions, and 12-Item Short Form Health Survey scores and clinical and radiographic examinations. Radiographic images were reviewed for metal debris according to Endrizzi. Mixed effects repeated measures analysis of variance for within- and between-group comparisons were performed. RESULTS: Of the 104 patients who consented, 93 were randomized (46 TM; 47 POLY). There were no differences between groups at baseline (TM: mean age 66.5 years [standard deviation (SD) 6.4], 24 male and 22 female; and POLY: mean age 68.4 years [SD 5.5], 23 male / 24 female). Mean (SD) WOOS scores at baseline and 2 and 5 years were as follows: TM, 32 (21), 92 (13), and 93 (11); POLY, 27 (15), 93 (11), and 93 (10), respectively. No statistical or clinically relevant differences were noted with patient-reported outcomes between groups. Metal debris was observed in 11 (23.9%) patients, but outcomes were not negatively impacted, and debris severity was minor (grades 1 and 2). Complication rates were similar between groups (TM: 7 of 46 [15.2%], and POLY: 8 of 47 [17.0%]; P = .813). No aseptic glenoid failures were reported, but 1 patient in the TM group required revision because of infection. CONCLUSIONS: Our short-term (2-year) findings were maintained with longer follow-up. At 5 years postoperation, there were no statistically or clinically significant differences between an uncemented second-generation TM glenoid and a cemented polyethylene glenoid with respect to disease-specific quality of life or patient-reported outcomes. No glenoid implant failures were reported, and complication rates were similar between groups. Only one complication was glenoid related (1 infection in the TM group). Metal debris was observed in 23.9% of patients with a TM glenoid but did not negatively influence implant survival, patient-reported outcomes, or shoulder function.

Comparison of Permanent Hair Removal Procedures before Gender-Affirming Vaginoplasty: Why We Should Consider Laser Hair Removal as a First-Line Treatment for Patients Who Meet Criteria.

INTRODUCTION: Permanent genital hair removal is required before gender-affirming vaginoplasty to prevent hair-related complications. No previous studies have directly compared the relative efficacy, costs, and patient experiences with laser hair removal (LHR) vs electrolysis treatments. Food and Drug Administration (FDA) oversight of medical devices is poorly understood and commonly misrepresented, adversely affecting patient care. AIM: This study compares treatment outcomes of electrolysis and LHR for genital hair removal and investigates FDA regulation of electrolysis and LHR devices. METHODS: Penile-inversion vaginoplasty and shallow-depth vaginoplasty patients completed surveys about their preoperative hair removal, including procedure type, number/frequency of sessions, cost, and discomfort. Publicly available FDA-review documents and databases were reviewed. MAIN OUTCOMES MEASURE: Compared to electrolysis, LHR was associated with greater efficiency, decreased cost, decreased pain, and improved patient satisfaction. RESULTS: Of 52 total (44 full-depth and 8 shallow-depth) vaginoplasty patients, 22 of 52 underwent electrolysis only, 15 of 52 underwent laser only, and 15 of 52 used both techniques. Compared to patients that underwent LHR only, patients that underwent only electrolysis required a significantly greater number of treatment sessions (mean 24.3 electrolysis vs 8.1 LHR sessions, P < .01) and more frequent sessions (every 2.4 weeks for electrolysis vs 5.3 weeks for LHR, P < .01) to complete treatment (defined as absence of re-growth over 2 months). Electrolysis sessions were significantly longer than LHR sessions (152 minutes vs 26 minutes, P < .01). Total treatment costs for electrolysis ($5,161) were significantly greater than for laser ($981, P < .01). Electrolysis was associated with greater pain and significantly increased need for pretreatment analgesia, which further contributed to higher net costs for treatment with electrolysis vs laser. Many LHR and electrolysis devices have been FDA-cleared for safety, but the FDA does not assess or compare clinical efficacy or efficiency. CLINICAL IMPLICATIONS: For patients with dark-pigmented hair, providers should consider LHR as the first-line treatment option for preoperative hair removal before gender-affirming vaginoplasty. STRENGTH AND LIMITATIONS: This is the first study to compare electrolysis and LHR for genital hair removal. The discussion addresses FDA review/oversight of devices, which is commonly misrepresented. Limitations include the survey format for data collection. CONCLUSION: When compared with electrolysis, LHR showed greater treatment efficiency (shorter and fewer treatment sessions to complete treatment), less pain, greater tolerability, and lower total cost. Our data suggests that, for patients with dark genital hair, providers should consider recommending laser as the first-line treatment for permanent genital hair removal before vaginoplasty. Yuan N, Feldman A, Chin P, et al. Comparison of Permanent Hair Removal Procedures before Gender-Affirming Vaginoplasty: Why We Should Consider Laser Hair Removal as a First-Line Treatment for Patients Who Meet Criteria. Sex Med 2022;10:100545.

Glenoid Component Position Does Not Affect Short-Term Clinical and Radiologic Outcomes in Total Shoulder Arthroplasty.

BACKGROUND: Malpositioning of the glenoid component in total shoulder arthroplasty (TSA) remains the primary source of loosening. The purpose of this study is firstly, to quantify postoperative glenoid component position in patients having a TSA and secondly, to explore whether glenoid component radiolucency is associated with glenoid position, clinical outcomes and patient-reported measures in the short-term (two year) follow-up period. METHODS: This study was a sub-study of a larger clinical trial that included patients who underwent a TSA and who were randomized into two different glenoid types with a minimum two-year follow-up period. Post-operative radiographic assessments (six weeks and two years) were used to measure glenoid component position (version, inclination, offset) and humeral head centering anterior-posterior (AP) and superior-inferior (SI), and to assess glenoid component radiolucent scoring (modified Lazarus). Pre-operative X-rays were used to measure glenoid version, inclination and Walch classification. Patient-reported measures (PROMs) included the EQ-5D health slider and the Western Ontario Osteoarthritis (WOOS) and American Shoulder and Elbow Surgeons (ASES) score and were captured at baseline and two years postoperative. Clinical outcomes including range of motion and complications were also documented. Statistical analysis included t-tests and regression modeling. RESULTS: Ninety-one patients with an average age of 69.9 ± 6.2 years were included in this study. Glenoid component position improved significantly in version (-19.4 ± 8.6° to -17.7 ± 8.5°; p < 0.045) and inclination (11.5 ± 7.1° to 5.9 ± 6.3°; p < 0.00001) from preoperative to six weeks postoperative. Glenoid component offset in SI and humeral head centering in AP remained unchanged throughout the follow-up. Radiolucency (Lazarus classification) was recorded in 21 cases (17.3%) with a Lazarus score of 1 (15 cases) and 2 (6 cases). The EQ-5D health slider, WOOS and ASES, and ROM confirmed continuous improvements from the preoperative scores to the two-year follow-up (p < 0.05). Regression models showed no correlation between glenoid component radiolucency at two years and the postoperative week six glenoid component position; however, female gender was a significant variable. CONCLUSION: Glenoid component changes from its original native glenoid were observed following TSA. Glenoid inclination was improved more than version from baseline, and the humeral head remained well-centered in AP and SI at two years. Radiolucency of the glenoid at two years is not negatively associated with PROMs or component position; however, female gender was identified as a significant predictor and warrants further investigation. Complications are not associated with glenoid position or radiolucency, but longer-term follow-up is required.

Treatment of Facial Fractures at Safety-Net Hospitals: A National Analysis of Inpatient Burden and Cost.

PURPOSE: Safety-net hospitals (SNHs) are vital in the care of trauma populations, but little is known about the burden of facial trauma presenting to SNHs. The authors sought to characterize the presentation and treatment of facial fractures across SNHs and determine the association between SNH care and healthcare utilization in patients undergoing fracture repair. METHODS: Adult patients presenting with a facial fracture as their primary admitting diagnosis from the year 2012 to 2015 were identified in the National Inpatient Sample. The "safety-net burden" of each hospital was defined based on the proportion of Medicaid and self-pay discharges. Patient factors analyzed were sex, race, age, income level, insurance status, fracture location, and comorbidities. Hospital factors analyzed were safety-net burden, teaching status, geographic region, bed size, and ownership status. The main outcomes were length of stay (LOS), hospital costs, time to repair, and postoperative complications. RESULTS: Of 78,730 patients, 27,080 (34.4%) were treated at SNHs and 24,844 (31.6%) were treated at non-SNHs. Compared to non-SNHs, patients treated at SNHs were more likely to undergo operative repair at SNHs (65.8% versus 53.9%, P < 0.001). Overall mean LOS was comparable between non-SNH and SNH (3.43 versus 3.38 days, P = 0.611), as was mean hospital cost ($15,487 versus $15,169, P = 0.434). On multivariate linear regression, safety-net status was not a predictor of increased LOS, cost, or complications. However, safety-net status was significantly associated with lower odds of undergoing repair within 48 hours of admission (odds ratio 0.783, 95% confidence interval = 0.680-0.900, P = 0.001). CONCLUSIONS: Safety-net hospitals are able to treat facial trauma patients with greater injury burden and lower socioeconomic resources without increased healthcare utilization. Healthcare reform must address the financial challenges that endanger these institutions to ensure timely treatment of all patients.

Using the modified frailty index to predict negative outcomes in free-flap breast reconstruction: A National Surgical Quality Improvement Project-based study.

BACKGROUND: Post-mastectomy free-flap breast reconstruction is becoming increasingly common in the United States. However, predicting which patients may suffer complications remains challenging. We sought to apply the validated modified frailty index (mFI) to free-flap breast reconstruction in breast cancer patients and determine its utility in predicting negative outcomes. METHODS: We conducted a retrospective study using National Surgical Quality Improvement Project (NSQIP). All patients who had a CPT code of 19364, indicative of free tissue transfer for breast cancer reconstruction, were included. Data on preoperative characteristics and postoperative outcomes were collected. Patients were separated based on the number of mFI factors present into three categories: 0, 1, and > 2 factors. Preoperative demographics, clinical status, and other comorbidities were also studied. Negative outcomes were compared using multivariate logistic regression. RESULTS: 11,852 patients (mean age 50.9 ± 9.5) were found; 24.2% had complications, comparable to previous literature. mFI is predictive of all types of negative outcomes. 22.5% of all patients with 0 mFI, 27.7% of patients with 1 mFI and 34.2% of patients with at least two mFI had a negative outcome. The most common factors contributing to the mFI were history of hypertension (24.8%) and diabetes (6.1%). mFI was found to be an isolated risk factor for negative outcomes, along with steroid use, American Society of Anesthesiology (ASA) classification, body mass index, and immediate, and bilateral operations. CONCLUSIONS: This NSQIP-based study for patients undergoing free flap breast reconstruction shows that the mFI holds predictive value regarding negative outcomes. This provides more information to properly counsel patients before free flap breast reconstruction surgery.

Two-year results of a multi-centre, randomized controlled trial comparing a second-generation uncemented trabecular metal-backed versus cemented polyethylene glenoid component in total shoulder arthroplasty.

AIMS: To report early (two-year) postoperative findings from a randomized controlled trial (RCT) investigating disease-specific quality of life (QOL), clinical, patient-reported, and radiological outcomes in patients undergoing a total shoulder arthroplasty (TSA) with a second-generation uncemented trabecular metal (TM) glenoid versus a cemented polyethylene glenoid (POLY) component. METHODS: Five fellowship-trained surgeons from three centres participated. Patients aged between 18 and 79 years with a primary diagnosis of glenohumeral osteoarthritis were screened for eligibility. Patients were randomized intraoperatively to either a TM or POLY glenoid component. Study intervals were: baseline, six weeks, six-, 12-, and 24 months postoperatively. The primary outcome was the Western Ontario Osteoarthritis Shoulder QOL score. Radiological images were reviewed for metal debris. Mixed effects repeated measures analysis of variance for within and between group comparisons were performed. RESULTS: A total of 93 patients were randomized (46 TM; 47 POLY). No significant or clinically important differences were found with patient-reported outcomes at 24-month follow-up. Regarding the glenoid components, there were no complications or revision surgeries in either group. Grade 1 metal debris was observed in three (6.5%) patients with TM glenoids at 24 months but outcomes were not negatively impacted. CONCLUSION: Early results from this RCT showed no differences in disease-specific QOL, radiographs, complication rates, or shoulder function between uncemented second-generation TM and cemented POLY glenoids at 24 months postoperatively. Revision surgeries and reoperations were reported in both groups, but none attributed to glenoid implant failure. At 24 months postoperatively, Grade 1 metal debris was found in 6.5% of patients with a TM glenoid but did not negatively influence patient-reported outcomes. Longer-term follow-up is needed and is underway. Cite this article: Bone Jt Open 2021;2(9):728-736.

Correlation of ThyroSeq Results with Surgical Histopathology in Cytologically Indeterminate Thyroid Nodules.

The ThyroSeq next-generation sequencing test refines the risk of malignancy in cytologically indeterminate thyroid nodules. Specific genetic alterations have distinct cancer probabilities and clinical phenotypes. There is limited data on the association between specific genetic alterations and histopathologic features. The aim of this study was to evaluate specific ThyroSeq alterations in prognosticating high-risk histopathologic characteristics. We performed a retrospective single-institution study of all patients diagnosed with indeterminate thyroid nodules (May 2016-December 2019) who had a mutation identified with ThyroSeq v2 or v3 and underwent surgical resection. Specific genetic alterations were correlated with surgical histopathology. The main outcomes were risk of malignancy and structural recurrence risk based on histopathologic features and the 2015 American Thyroid Association (ATA) risk stratification. Of the 78 nodules, 50 (64%) were thyroid cancer or noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) on surgical histopathology. Nodules with high-risk TERT or TP53 combination mutations (TERT/TP53) and those with BRAF-like mutations were associated with a 100% probability of cancer and higher rates of extrathyroidal extension and regional nodal involvement than nodules with RAS-like mutations. Among nodules with RAS-like mutations, there was an even distribution between benign, NIFTP, and malignant results, the latter of which were all ATA low risk for structural disease recurrence. Overall, TERT/TP53 and BRAF-like ThyroSeq mutations are associated with an increased cancer probability and risk of recurrence defined by histopathologic features, while RAS-like mutations are associated with lower cancer probability and indolent disease. Individualized management, including extent of surgery, should be considered based on specific genetic alterations found in cytologically indeterminate thyroid nodules.

Portable and Reconfigurable Wrist Robot Improves Hand Function for Post-Stroke Subjects.

Rehabilitation robots have become increasingly popular for stroke rehabilitation. However, the high cost of robots hampers their implementation on a large scale. This paper implements the concept of a modular and reconfigurable robot, reducing its cost and size by adopting different therapeutic end effectors for different training movements using a single robot. The challenge is to increase the robot's portability and identify appropriate kinds of modular tools and configurations. Because literature on the effectiveness of this kind of rehabilitation robot is still scarce, this paper presents the design of a portable and reconfigurable rehabilitation robot and describes its use with a group of post-stroke patients for wrist and forearm training. Seven stroke subjects received training using a reconfigurable robot for 30 sessions, lasting 30 min per session. Post-training, statistical analysis showed significant improvement of 3.29 points (16.20%, p = 0.027) on the Fugl-Meyer assessment scale for forearm and wrist components. Significant improvement of active range of motion was detected in both pronation-supination (75.59%, p = 0.018) and wrist flexion-extension (56.12%, p = 0.018) after the training. These preliminary results demonstrate that the developed reconfigurable robot could improve subjects' wrist and forearm movement.

Characterisation, degradation and regeneration of luminescent Ag29 clusters in solution.

Luminescent Ag clusters are prepared with lipoic acid (LA) as the ligand. Using a combination of mass spectrometry, optical spectroscopy and analytical ultracentrifugation, the clusters are found to be highly monodisperse with mass 5.6 kDa. We assign the chemical composition [Ag29(LA)12]3- to the clusters, where LA likely binds in a bidentate fashion. The Ag29 clusters show slow degradation, retaining their deep red emission for at least 18 months if stored in the dark. Purification or exposure to light results in faster degradation. No other cluster species are observed during the degradation process. Once degraded, the clusters could easily be regenerated using NaBH4, which is not usually observed for thiolate-capped Ag clusters.

Optical imaging as an expansion of nuclear medicine: Cerenkov-based luminescence vs fluorescence-based luminescence.

Integration of optical imaging technologies can further strengthen the field of radioguided surgery. Rather than using two separate chemical entities to achieve this extension, hybrid imaging agents can be used that contain both radionuclear and optical properties. Two types of such hybrid imaging agents are available: (1) hybrid imaging agents generated by Cerenkov luminescence imaging (CLI) of ß-emitters and (2) hybrid imaging agents that contain both a radioactive moiety and a fluorescent dye. One major challenge clinicians are now facing is to determine the potential value of these approaches. With this tutorial review we intend to clarify the differences between the two approaches and highlight the clinical potential of hybrid imaging during image-guided surgery applications.

Enhanced luminescence of Ag nanoclusters via surface modification.

UNLABELLED: In this work we present a detailed study on the influence of surface modifications for luminescent silver (Ag) clusters. Ag clusters (25 atoms) capped with dihydrolipoic acid show a distinct absorbance spectrum with several sharp transitions, and relative broad deep red luminescence with a quantum yield of 5% combined with a remarkably long luminescence lifetime of ~3 µs at room temperature. Both pH and the presence of coordinating ligands influence the absorbance spectra and fluorescence intensity. A strong increase in luminescence intensity up to 45% quantum yield could be induced by coordination with PEG ligands. CONCLUSION: the surface coordination of the Ag clusters strongly influences the optical properties.

Multispectral visualization of surgical safety-margins using fluorescent marker seeds.

Optical guidance provided by luminescent marker seeds may be suitable for intraoperative determination of appropriate resection margins. In phantom studies we compared the tissue penetration of several organic dyes and inorganic particles (quantum dots; QDs) after incorporation in experimental marker seeds. The tissue penetration of (near infra-) red organic dyes was much better than the penetration of dyes and QDs with an emission in the visible range. By combining 3 dyes in a single marker seed we were able to distinguish four depth ranges. The difference in tissue penetration between the dyes and QDS enabled depth estimation via a 'traffic light' approach.

Peptide-functionalized luminescent iridium complexes for lifetime imaging of CXCR4 expression.

The chemokine receptor 4 (CXCR4) is over-expressed in 23 types of cancer in which it plays a role in, among others, the metastatic spread. For this reason it is a potential biomarker for the field of diagnostic oncology. The antagonistic Ac-TZ14011 peptide, which binds to CXCR4, has been conjugated to luminescent iridium dyes to allow for CXCR4 visualization. The iridium dyes are cyclometalated octahedral iridium(III) 2-phenylpyridine complexes that can be functionalized with one, two or three targeting Ac-TZ14011 peptides. Confocal microscopy and fluorescence lifetime imaging microscopy (FLIM) showed that the peptide-iridium complex conjugates can be used to visualize CXCR4 expression in tumor cells. The CXCR4 receptor affinity and specific cell binding of the mono-, di- and trimeric peptide derivatives were assessed by using flow cytometry. The three derivatives possessed nanomolar receptor affinity and could distinguish between cell lines with different CXCR4 expression levels. This yields the first example of a neutral iridium(III) complex functionalized with peptides for FLIM-based visualization of a cancer associated membrane receptor.

(Non-targeted) radioactive/fluorescent nanoparticles and their potential in combined pre- and intraoperative imaging during sentinel lymph node resection.

One clinical precedent for the use of nanosized imaging agents is the localization of the tumor draining sentinel lymph nodes. In this application, radiocolloids such as (99m)Tc-NanoColl are currently used to plan the surgical procedure and to provide acoustic guidance during the intervention. Additional injections of dyes are common to provide optical surgical guidance. Bimodal imaging agents, which are both radioactive and fluorescent, have the potential to be used for both surgical planning and intraoperative fluorescence guidance towards the sentinel lymph nodes. This review provides an overview of the radioactive, fluorescent, and size properties of (non-targeted) bimodal nanoparticles, and their (potential) value in sentinel lymph node detection.

Tumor bracketing and safety margin estimation using multimodal marker seeds: a proof of concept.

Accurate tumor excision is crucial in the locoregional treatment of cancer, and for this purpose, surgeons often rely on guide wires or radioactive markers for guidance toward the lesion. Further improvement may be obtained by adding optical guidance to currently used methods, in the form of intra-operative fluorescence imaging. To achieve such a multimodal approach, we have generated markers that can be used in a pre-, intra-, and post-operative setting, based on a cocktail of a dual-emissive inorganic dye, lipids, and pertechnetate. Phantom experiments demonstrate that these seeds can be placed accurately around a surrogate tumor using ultrasound. Three-dimensional bracketing provides delineation of the entire lesion. Combined with the multimodal nature, this provides the opportunity to predetermine the resection margins by validating the placement accuracy using multiple imaging modalities (namely, x ray, MRI, SPECT/CT, and ultrasound). The dual-emissive fluorescent properties of the dye provide the unique opportunity to intra-operatively estimate the depth of the seed in the tissue via multispectral imaging: emission green λmax=520 nm≤5 mm penetration versus emission red λmax=660 nm≤12 mm penetration. By using particles with different colors, the original geographic orientation of the excised tissue can be determined.

A self-assembled multimodal complex for combined pre- and intraoperative imaging of the sentinel lymph node.

Specific removal of the sentinel lymph node (SLN) during breast cancer surgery presents physicians with the opportunity to detect early metastatic disease. To increase the accuracy of intraoperative SLN detection, new methods with higher sensitivity and specificity are required. We have quantitatively compared conventional preoperative lymphoscintigraphy with albumin radiocolloids ((99m)Tc-NanoColl) with optical intraoperative guidance using the near infrared dye indocyanine green (ICG) in an orthotopic mouse model for metastatic breast cancer. Furthermore, we have applied a self-assembled multimodal complex, in which ICG is non-covalently bound to the albumin radiocolloid, to attain identical dynamics of the radioactive and optical components. The SLN specificity of the multimodal complex is similar to conventional lymphoscintigraphy, while the fluorescent signal-to-noise ratio is improved by 86% compared to ICG alone. In addition, the multimodal complex permits scintigraphic validation of the fluorescent findings. The multimodal ICG-(99m)Tc-NanoColl complex can be used both for lymphoscintigraphy by preoperative single photon emission computed tomography/computed tomography and for surgical navigation by intraoperative fluorescence imaging.

Dual-emissive quantum dots for multispectral intraoperative fluorescence imaging.

Fluorescence molecular imaging is rapidly increasing its popularity in image guided surgery applications. To help develop its full surgical potential it remains a challenge to generate dual-emissive imaging agents that allow for combined visible assessment and sensitive camera based imaging. To this end, we now describe multispectral InP/ZnS quantum dots (QDs) that exhibit a bright visible green/yellow exciton emission combined with a long-lived far red defect emission. The intensity of the latter emission was enhanced by X-ray irradiation and allows for: 1) inverted QD density dependent defect emission intensity, showing improved efficacies at lower QD densities, and 2) detection without direct illumination and interference from autofluorescence.

In vitro toxicity studies of polymer-coated gold nanorods.

We evaluated cellular responses to polymer-treated gold nanorods, which were synthesized using the standard wet-chemistry method that utilizes hexadecyltrimethylammonium bromide (CTAB). The nanorod dispersions were coated with either polystyrene sulfonate (PSS) or polyethylene glycol (PEG). Two sizes of nanorods were tested, with optical responses peaking at 628 and 773 nm. The cells were from mammary adenocarcinoma (SKBR3), Chinese Hamster Ovary (CHO), mouse myoblast (C2C12) and Human Leukemia (HL60) cell lines. Their mitochondrial function following exposure to the nanorods were assessed using the MTS assay. We found PEGylated particles to have superior biocompatibility compared with PSS-coated nanorods, which showed substantial cytotoxicity. Electron microscopy showed no cellular uptake of PEGylated particles compared with their PSS counterparts. PEGylated gold nanorods also exhibited better dispersion stability in the presence of cell growth medium; PSS-coated rods tended to flocculate or cluster. In the case of the PSS particles, toxicity correlated with surface area across the two sizes of nanorods studied.

Biaxially oriented CdSe nanorods.

The shape, structure, and orientation of rubbing-aligned cadmium selenide (CdSe) nanorods on polymer coated glass substrates have been studied using transmission electron microscopy (TEM) and grazing incidence X-ray scattering combined with computer simulations. The nanorods are found to be of wurtzite structure and highly monodisperse, and have an essentially ellipsoidal shape with short axes of approximately 8 nm and long axis of approximately 22 nm. The nanorods exhibit preferred biaxial orientation with the hexagonal a-c-plane parallel to the sample surface and the c-axis oriented along the rubbing direction of the sample. Some tendency of smectic-A ordering is observed. A quantitative model incorporating atomic structure, rod shape, and preferred orientation was developed for numerically simulating the diffraction peak positions, widths, and intensities, giving good correlation with the experimental observations.

Highly luminescent ultranarrow Mn doped ZnSe nanowires.

Colloidal Mn-doped ZnSe nanowires with diameters of 1-3 nm and lengths up to 200 nm were prepared from Li(4)[Zn(10)Se(4)(SPh)(16)] clusters and manganese stearate. The nanowires exhibit optical properties that depend on size, shape, and doping level. The manganese photoluminescence is slightly polarized perpendicular to the long axis and reaches a quantum yield of 40% after passivating the crystals with a CdSe shell.