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The detection of tumor biomarkers in the early stage is highly desirable for the therapy of cancer. However, rapid, low-cost, sensitive, and selective detection of biomarkers remains a challenge owing to the sequence homology, short length, and low abundance. This Research Article describes the synthesis of a novel carcinoembryonic antigen (CEA) probe using hollow porous gold nanoparticles (HPGNPs) with roughened surface based on fluorescence quenching. For specific detection of CEA, the surface of HPGNP is modified by carboxyl modification, carboxyl activation, and antibody conjugation. Furthermore, to enhance the detection performance, we have systematically optimized the parameters, such as particle size, surfactants, surface roughness, surface hole size, and the molecule-particle distance (MPD). The results demonstrate that the fluorescence quenching efficiency would be enhanced with a larger particle size and surface hole size, roughened surface and a greater MPD. Also, with careful inspection of different surfactants of CTAB and PVP, we find that PVP has the optimal performance on fluorescence quenching. Under these optimized conditions, CEA could be detected with an ultralow detection limit of 1.5 pg/mL, and the probe shows a linear range from 2 to 100 pg/mL. The limit of detection is an order of intensity lower than related methods. Interference experiment results have shown that the influence of the interfering proteins could be neglected in the detection procedure.

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Synthesis of Ag/Au core–shell nanoparticles with two LSPR modes and the specific detection of Hg2+and Pb2+.

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Morphology modification of nanostructures is of great interest, because it can be used to fabricate nanostructures which are hard to be done using other methods. Different from traditional lithographic technique which is slow and expensive, morphology modification is easy, cheap, and reproducible. In this paper, modification of the optical and morphological properties of a hollow gold nanoshell (HGNS) is achieved by using H2O2 as an oxidizer. The reshaping of these nanostructures has been demonstrated as a consequence of an oxidation process in which HGNSs are dissolved by H2O2 under the acidic conditions provided by HCl. We investigate the oxidation process by a transmission electron microscope and propose a reshaping model involving four different shapes (HGNS, HGNS with hole, gold nanoring, and C-shaped gold nanoparticle) which are corresponding to the oxidation products of HGNSs at different pH values. Besides, the surface enhanced Raman scattering (SERS) activity of each oxidation product has been evaluated by using rhodamine 6G as the Raman active probe. It has been observed that the C-shaped gold nanoparticles which are corresponding to the oxidation products at the minimum pH value have the highest SERS activity and this result can also be interpreted by discrete-dipole approximation simulations. We demonstrate that the morphology modification of HGNSs becomes possible in a controlled manner using wet chemistry and can be used in preparation of gold nanoparticles such as HGNS with hole, gold nanoring, and C-shaped gold nanoparticle with large SERS activity. These nanostructures must have potential use in many plasmonic areas, including sensing, catalysis, and biomedicine.

Objective: At present, it is still uncertain whether single screw has the same stability as double screws in the treatment of ulnar coronal process basal fracture (Regan-Morry type III). So, we aimed to compare the pull-out force and anti-rotation torque of anterior single/double screw-cancellous bone fixation (aSSBF, aDSBF) in this fracture, and further study the influencing factors on anatomical and biomechanical stability of smart screw internal fixations.Methods: A total of 63 adult volunteers with no history of elbow injury underwent elbow CT scanning with associated three-dimensional reconstruction that enabled the measurements of bone density and fixed length of the proximal ulna and coronoid. The models of coronal process basal fracture, aSSBF and aDSBF, were developed and validated. Using the finite element model test, the sensitivity analysis of pull-out force and rotational torque was carried out. Results:The pull-out force of aSSBF model was positively correlated with the density of the cancellous bone and linearly related to the fixed depth of the screw. The load pattern of pull-out force of aDSBF model was similar to that of aSSBF model. The ultimate torque of aDSBF model was higher than that of aSSBF model, but the load pattern of ultimate torque of both models was similar to each other when the fracture reset was satisfactory, and the screw nut attaches closely to coronoid process. Moreover, with enhancement of initial pre-tightening force, the increase of ultimate torque of both models was small. Conclusions:In addition to three pull-out stability factors of smart screw fixations, fracture surface fitting degree and nut fitting degree are the other two important anatomical and biomechanical stability factors of smart screw fixations both for rotational stability. When all pull-out stability and rotational stability factors meet reasonable conditions simultaneously, single or double screw fixation methods are stable for the treatments of ulnar coronoid basal fractures.