Direct electrical control of IgG conformation and functional activity at surfaces

We have devised a supramolecular edifice involving His-tagged protein A and antibodies to yield surface immobilized, uniformly oriented, IgG-type, antibody layers with Fab fragments exposed off an electrode surface. We demonstrate here that we can affect the conformation of IgGs, likely pushing/pulling electrostatically Fab fragments towards/from the electrode surface. A potential difference between electrode and solution acts on IgGs’ charged aminoacids modulating the accessibility of the specific recognition regions of Fab fragments by antigens in solution. Consequently, antibody-antigen affinity is affected by the sign of the applied potential: a positive potential enables an effective capture of antigens; a negative one pulls the fragments towards the electrode, where steric hindrance caused by neighboring molecules largely hampers the capture of antigens. Different experimental techniques (electrochemical quartz crystal microbalance, electrochemical impedance spectroscopy, fluorescence confocal microscopy and electrochemical atomic force spectroscopy) were used to evaluate binding kinetics, surface coverage, effect of the applied electric field on IgGs, and role of charged residues on the phenomenon described. These findings expand the concept of electrical control of biological reactions and can be used to gate electrically specific recognition reactions with impact in biosensors, bioactuators, smart biodevices, nanomedicine, and fundamental studies related to chemical reaction kinetics

Optimization of Optical Properties of Polycarbonate Film with Thiol Gold-Nanoparticles

A new nanostructured composite film based on thiol gold nanoparticles dispersed in polycarbonate and prepared by evaporating a solution of 1-dodecanthiol gold nanoparticles and polycarbonate was developed for applications as optical lenses. Lenses with superior mechanical properties, coloring and UV ray absorption and with the same transparency as the matrix were obtained. The supporting highly transparent polycarbonate matrix and the chloroform solution of thiol gold nanoparticles, 3 nm mean size, was mixed according to a doping protocol employing different concentrations of thiol gold nanoparticles vs. polycarbonate. The presence of nanoparticles in the polymer films was confirmed by the spectrophotometric detection of the characteristic absorbance marker peak at 540–580 nm. The nanostructured films obtained show a better coverage in the UV-vis range (250–450 nm) even at very low doping ratios, of the order of 1:1,000. These results offer a very promising approach towards the development of efficient nanostructured materials for applications to optical lenses

Combined characterization of bovine polyhemoglobin microcapsules by UV–Vis absorption spectroscopy and cyclic voltammetry

reserved7siPolyhemoglobin produced from pure bovine hemoglobin by reaction with PEG bis(N-succynimidil succinate) as a cross-linking agent was encapsulated in gelatin and dehydrated by freeze–drying. Free carboxyhemoglobin and polyhemoglobin microcapsules were characterized by UV–Vis spectroscopy in the absorption range 450–650 nm and cyclic voltammetry in the voltage range from −0.8 to 0.6 mV to evaluate the ability to break the bond with carbon monoxide and to study the carrier’s affinity for oxygen, respectively. SEM used to observe the shape of cross-linked gelatin-polyhemoglobin microparticles showed a regular distribution of globular shapes, with mean size of ~750 nm, which was ascribed to gelatin. Atomic absorption spectroscopy was also performed to detect iron presence in microparticles. Cyclic voltammetry using an Ag–AgCl electrode highlighted characteristic peaks at around −0.6 mV that were attributed to reversible oxygen bonding with iron in oxy-polyhemoglobin structure. These results suggest this technique as a powerful, direct and alternative method to evaluate the extent of hemoglobin oxygenation.mixedKnirsch, Marcos Camargo; Dell’Anno, Filippo; Salerno, Marco; Larosa, Claudio; Polakiewicz, Bronislaw; Eggenhöffner, Roberto; Converti, AttilioKnirsch, Marcos Camargo; Dell’Anno, Filippo; Salerno, Marco; Larosa, Claudio; Polakiewicz, Bronislaw; Eggenhoffner, Roberto; Converti, Attili

Quality of life in older adults after major cancer surgery: the GOSAFE international study

Abstract Background Accurate quality of life (QoL) data and functional results after cancer surgery are lacking for older patients. The international, multicenter Geriatric Oncology Surgical Assessment and Functional rEcovery after Surgery (GOSAFE) Study compares QoL before and after surgery and identifies predictors of decline in QoL. Methods GOSAFE prospectively collected data before and after major elective cancer surgery on older adults (≥70 years). Frailty assessment was performed and postoperative outcomes recorded (30, 90, and 180 days postoperatively) together with QoL data by means of the three-level version of the EuroQol five-dimensional questionnaire (EQ-5D-3L), including 2 components: an index (range = 0-1) generated by 5 domains (mobility, self-care, ability to perform the usual activities, pain or discomfort, anxiety or depression) and a visual analog scale. Results Data from 26 centers were collected (February 2017-March 2019). Complete data were available for 942/1005 consecutive patients (94.0%): 492 male (52.2%), median age 78 years (range = 70-95 years), and primary tumor was colorectal in 67.8%. A total 61.2% of all surgeries were via a minimally invasive approach. The 30-, 90-, and 180-day mortality was 3.7%, 6.3%, and 9%, respectively. At 30 and 180 days, postoperative morbidity was 39.2% and 52.4%, respectively, and Clavien-Dindo III-IV complications were 13.5% and 18.7%, respectively. The mean EQ-5D-3L index was similar before vs 3 months but improved at 6 months (0.79 vs 0.82; P < .001). Domains showing improvement were pain and anxiety or depression. A Flemish Triage Risk Screening Tool score greater than or equal to 2 (odds ratio [OR] = 1.58, 95% confidence interval [CI] = 1.13 to 2.21, P = .007), palliative surgery (OR = 2.14, 95% CI = 1.01 to 4.52, P = .046), postoperative complications (OR = 1.95, 95% CI = 1.19 to 3.18, P = .007) correlated with worsening QoL. Conclusions GOSAFE shows that older adults’ preoperative QoL is preserved 3 months after cancer surgery, independent of their age. Frailty screening tools, patient-reported outcomes, and goals-of-care discussions can guide decisions to pursue surgery and direct patients’ expectations