Thermoplastic nanofluidic devices for biomedical applications

This review presents an overview of recent advancements in the fabrication, surface modification and applications of thermoplastic nanofluidic devices

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Characterization of activated cyclic olefin copolymer: Effects of ethylene/norbornene content on the physiochemical properties

The ethylene/norbornene content within cyclic olefin copolymer (COC) is well known to affect the chemical and physical properties of the copolymer, such as the glass transition temperature (Tg) and transparency. However, no work has been reported evaluating the effects of the ethylene/norbornene content on the surface properties of COC following UV/O3 or O2 plasma activation. Activation with either O2 plasma or UV/O3 is often used to assist in thermal assembly of fluidic devices, increasing the wettability of the surfaces, or generating functional scaffolds for the attachment of biological elements. Thus, we investigated differences in the physiochemical surface properties of various ethylene/norbornene compositions of COC following activation using analytical techniques such as water contact angle (WCA), ATR-FTIR, XPS, TOF-SIMS, UV-VIS, AFM and a colorimetric assay utilizing Toluidine Blue O (TBO). Results showed that increased norbornene content led to the generation of more oxygen containing functionalities such as alcohols, ketones, aldehydes and carboxyl groups when activated with either UV/O3 or O2 plasma. Specifically, COC with ???60% norbornene content showed a significantly higher -COOH functional group density when compared to COC with a 50% norbornene content and COC with a 35% norbornene content following UV/O3 or O2 plasma activation. Furthermore, COC with large norbornene contents showed a smaller average RMS roughness (0.65 nm) when compared to COC containing low norbornene contents (0.95 nm) following activation making this substrate especially suited for nanofluidic applications, which require smooth surfaces to minimize effects arising from dielectrophoretic trapping or non-specific adsorption. Although all COC substrates showed >90% transparency at wavelengths >475 nm, COC possessing high norbornene contents showed significantly less transparency at wavelengths below 475 nm following activation, making optical detection in this region difficult. Our data showed distinct physiochemical differences in activated COC that was dependent upon the ethylene/norbornene content of the thermoplastic and thus, careful selection of the particular COC grade must be considered for micro- and nanofluidics.close

Thermoplastic nanofluidic devices for biomedical applications

Microfluidics is now moving into a developmental stage where basic discoveries are being transitioned into the commercial sector so that these discoveries can affect, for example, healthcare. Thus, high production rate microfabrication technologies, such as thermal embossing and/or injection molding, are being used to produce low-cost consumables appropriate for commercial applications. Based on recent reports, it is clear that nanofluidics offers some attractive process capabilities that may provide unique venues for biomolecular analyses that cannot be realized at the microscale. Thus, it would be attractive to consider early in the developmental cycle of nanofluidics production pipelines that can generate devices possessing sub150 nm dimensions in a high production mode and at low-cost to accommodate the commercialization of this exciting technology. Recently, functional sub-150 nm thermoplastic nanofluidic devices have been reported that can provide high process yield rates, which can enable commercial translation of nanofluidics. This review presents an overview of recent advancements in the fabrication, assembly, surface modification and the characterization of thermoplastic nanofluidic devices. Also, several examples in which nanoscale phenomena have been exploited for the analysis of biomolecules are highlighted. Lastly, some general conclusions and future outlooks are presented.ope

Fracture fixation in the operative management of hip fractures (FAITH): an international, multicentre, randomised controlled trial

Background Reoperation rates are high after surgery for hip fractures. We investigated the effect of a sliding hip screw versus cancellous screws on the risk of reoperation and other key outcomes. Methods For this international, multicentre, allocation concealed randomised controlled trial, we enrolled patients aged 50 years or older with a low-energy hip fracture requiring fracture fixation from 81 clinical centres in eight countries. Patients were assigned by minimisation with a centralised computer system to receive a single large-diameter screw with a side-plate (sliding hip screw) or the present standard of care, multiple small-diameter cancellous screws. Surgeons and patients were not blinded but the data analyst, while doing the analyses, remained blinded to treatment groups. The primary outcome was hip reoperation within 24 months after initial surgery to promote fracture healing, relieve pain, treat infection, or improve function. Analyses followed the intention-to-treat principle. This study was registered with ClinicalTrials.gov, number NCT00761813. Findings Between Mar