InstrumentationThermal Analysis. Standard thermal gravimetry experiments were performed on a TA Instruments Q5000IR TGA. Samples were heated in platinum pans from ambient temperature to 600.0°C at 20.0°C/min. A TA Instruments Q1000 Differential Scanning Calorimeter (DSC) was used to evaluate thermal transitions of the (co)polymers. Samples (~ 3-8 mg) were prepared in standard aluminum pans/lids and were first heated from ambient temperature to 160.0°C at a ramp rate of 20.0°C/min. Samples were subsequently cooled to -50.0°C at 25.0°C/min and finally heated to 160.0°C at 20.0°C/min. Glass transition temperatures are reported from the second heating as the mid-point of the heat flow derivative curve. The DSC was calibrated using indium standard (In; melting point, T m, In = 156.6 °C; provided by TA Instruments) according to the manufacturer's recommendation, which includes baseline and temperature calibrations.Additionally, standard thermal gravimetry experiments were performed on a TA Instruments Q5000IR TGA. Samples were heated in platinum pans from ambient temperature to 600.0°C at 20.0°C/min. Raman Microspectroscopy. Raman spectroscopy of thin polymer films were performed using a Renishaw 100 confocal micro-Raman system equipped with a CCD detector. A 632.8 nm HeNe laser was focused to 2 µm spot size with a 50x objective. Raman spectra were acquired using a 60 s integration time. Atomic ForceMicroscopy. A Digital Instruments Dimension 3100 atomic force microscope (AFM) was used in tapping mode to obtain height images of 1000 µm lines of a PGMA 73 -b-PVDMA 174 copolymer spin-coated from solution in CHCl 3 at a concentration of 0.75% wt and annealed under vacuum at 110 °C. The micropattern was made by photolithographic techniques. 1The amplitude set-point and proportional and integral gains were adjusted for each sample assuring optimal image quality. All measurements were done at a scanning rate of 0.5 Hz using silicon nitride cantilevers. An area of 8 µm × 8 µm at the edge of the pattern was initially surveyed in order to obtain a direct comparison of layer thickness values obtained by AFM and by ellipsometry. Then, a 2 µm × 2 µm area on the polymer layer was sampled, which allowed the film's topography and roughness to be examined.

Functional soft interfaces are of interest for a variety of technologies. We describe three methods for preparing substrates with alkyne groups, which show versatility for "click" chemistry reactions. Two of the methods have the same root: formation of thin, covalently attached, reactive interfacial layers of poly(glycidyl methacrylate) (PGMA) via spin coating onto silicon wafers followed by reactive modification with either propargylamine or 5-hexynoic acid. The amine or the carboxylic acid moieties react with the epoxy groups of PGMA, creating interfacial polymer layers decorated with alkyne groups. The third method consists of using copolymers comprising glycidyl methacrylate and propargyl methacrylate (pGP). The pGP copolymers are spin coated and covalently attached on silicon wafers. For each method, we investigate the factors that control film thickness and content of alkyne groups using ellipsometry, and study the nanophase structure of the films using neutron reflectometry. Azide-terminated polymers of methacrylic acid and 2-vinyl-4,4-dimethylazlactone synthesized via reversible addition-fragmentation chain transfer polymerization were attached to the alkyne-modified substrates using "click" chemistry, and grafting densities in the range of 0.007-0.95 chains nm(-2) were attained. The maximum density of alkyne groups attained by functionalization of PGMA with propargylamine or 5-hexynoic acid was approximately 2 alkynes nm(-3). The alkyne content obtained by the three decorating approaches was sufficiently high that it was not the limiting factor for the click reaction of azide-capped polymers.

Postpolymerization modification reactions are widely employed to prepare functional polymer brushes. Relatively little is known, however, about the distribution of functional groups in such postmodified brushes. Using neutron reflectometry and UV–vis spectroscopy as principal tools, this article investigates the p-nitrophenyl chloroformate (NPC)-mediated postpolymerization modification of poly(2-hydroxyethyl methacrylate) (PHEMA) brushes, prepared via surface-initiated atom transfer radical polymerization, with D-10 leucine and D-3 serine. The neutron reflectometry experiments indicate that the postpolymerization modification depends both on brush thickness and grafting density. Whereas for dense brushes, postpolymerization modification with D-10 leucine is limited to the top ∼200 Å of the brush, independently of the brush thickness, the extent of postmodification can be significantly enhanced by decreasing the grafting density of the brush or by using the more hydrophilic and sterically less demanding D-3 serine, which reflects the ability of this amino acid to more readily penetrate the brush. UV–vis experiments revealed that the NPC activation is also nonuniform, but brush thickness and grafting density dependent, which adds to brush thickness and density and the nature of the amino acid as another of a complex set of variables that determine the final distribution of functional groups in postmodified brushes.

We report the controlled radical polymerization of 2-vinyl-4,4-dimethyl azlactone (VDMA), a 2-alkenyl-2-oxazolin-5-one monomer that contains a polymerizable vinyl moiety and a highly reactive, pendant azlactone, as well as dilute solution properties and surface attachment and functionalization. Reversible addition−fragmentation chain transfer (RAFT) was used to polymerize VDMA in benzene at 65 °C using either 2-(2-cyanopropyl) dithiobenzoate (CPDB) or 2-dodecylsulfanylthiocarbonylsulfanyl-2-methylpropionic acid (DMP) as RAFT chain transfer agents (CTAs). The pseudo-first-order kinetics and resultant well-defined polymers of low polydispersity indicate that both CTAs afford control over the RAFT polymerization of VDMA. Dynamic and static light scattering and small-angle neutron scattering (SANS) were performed to determine the weight-average molecular weight, radius of gyration, and second virial coefficient of VDMA homopolymers in THF. Additionally, well-defined polymers of VDMA containing carboxyl end groups were covalently attached to epoxy-modified silicon wafers via esterification to produce polymeric scaffolds that can be subsequently functionalized for various bio-inspired applications.

Background Detecting cancer at early stages significantly increases patient survival rates. Because lethal solid tumors often produce few symptoms before progressing to advanced, metastatic disease, diagnosis frequently occurs when surgical resection is no longer curative. One promising approach to detect early-stage, curable cancers uses biomarkers present in circulating extracellular vesicles (EVs). To explore the feasibility of this approach, we developed an EV-based blood biomarker classifier from EV protein profiles to detect stages I and II pancreatic, ovarian, and bladder cancer. Methods Utilizing an alternating current electrokinetics (ACE) platform to purify EVs from plasma, we use multi-marker EV-protein measurements to develop a machine learning algorithm that can discriminate cancer cases from controls. The ACE isolation method requires small sample volumes, and the streamlined process permits integration into high-throughput workflows. Results In this case-control pilot study, comparison of 139 pathologically confirmed stage I and II cancer cases representing pancreatic, ovarian, or bladder patients against 184 control subjects yields an area under the curve (AUC) of 0.95 (95% CI: 0.92 to 0.97), with sensitivity of 71.2% (95% CI: 63.2 to 78.1) at 99.5% (97.0 to 99.9) specificity. Sensitivity is similar at both early stages [stage I: 70.5% (60.2 to 79.0) and stage II: 72.5% (59.1 to 82.9)]. Detection of stage I cancer reaches 95.5% in pancreatic, 74.4% in ovarian (73.1% in Stage IA) and 43.8% in bladder cancer. Conclusions This work demonstrates that an EV-based, multi-cancer test has potential clinical value for early cancer detection and warrants future expanded studies involving prospective cohorts with multi-year follow-up.