Immunosensors show great potential for the direct detection of biological molecules. The sensitivity of these affinity-based biosensors is dictated by the amount of receptor molecules immobilized on the sensor surface. An enlargement of the sensor area would allow for an increase of the binding capacity, hence a larger amount of immobilized receptor molecules. To this end, we use electrochemically deposited "gold black" as a porous sensor surface for the immobilization of proteins. In this paper, we have analyzed the different parameters that define the electrochemical growth of porous gold, starting from flat gold surfaces, using different characterization techniques. Applied potentials of -0.5 V versus a reference electrode were found to constitute the most adequate conditions to grow porous gold surfaces. Using cyclic voltammetry, a 16 times increase of the surface area was observed under these electrochemical deposition conditions. In addition, we have assessed the immobilization degree of alkanethiols and of proteins on these different porous surfaces. The optimized deposition conditions for realizing porous gold substrates lead to a 11.4-fold increase of thiol adsorption and a 3.3-fold increase of protein adsorption, using the quartz crystal microbalance (QCM-D) as a biological transducer system. Hence, it follows that the high specific area of the porous gold can amplify the final sensitivity of the original flat surface device.
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http://dx.doi.org/10.1021/ac049893u | DOI Listing |
ACS Omega
January 2025
Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States.
We report a new approach for fabricating gate-tunable thermal emissivity surfaces by spraying them on graphene ink. The devices consist of a multilayer graphene (MLG)/porous alumina membrane/gold stack, in which the MLG is deposited by spraying the graphene ink onto the porous membrane using an airbrush. The graphene ink consists of μm-sized flakes of MLG suspended in a solution of polyvinylpyrrolidone and ethylene glycol.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Key Laboratory of Polyoxometalate and Reticular Material Chemistry of Ministry of Education, Chemistry, Renmin Street, 130024, Changchun, CHINA.
High capacity, selective recovery and separation of precious metals from complex aqueous solutions is essential but remains a challenge in practical applications. Here, we prepared a thiophene-modified aromatic porous organic cage (T-PAC) with high stability for precise recognition and recovery of gold. T-PAC exhibits an outstanding gold uptake capacity of up to 2260 mg/g with fast adsorption kinetics and high adsorption selectivity.
View Article and Find Full Text PDFiScience
January 2025
Department of Environmental Science and Engineering, School of Engineering and Sciences, SRM University-AP, Amaravati, Andhra Pradesh 522240, India.
This article evaluated different production strategies, characteristics, and applications of biochar for ameliorating soil fertility and microbial diversity. The biochar production techniques are evolving, indicating that newer methods (including hydrothermal and retort carbonization) operate with minimum temperatures, yet resulting in high yields with significant improvements in different properties, including heating value, oxygen functionality, and carbon content, compared to the traditional methods. It has been found that the temperature, feedstock type, and moisture content play critical roles in the fabrication process.
View Article and Find Full Text PDFNanoscale
January 2025
Department of Chemistry, Indian Institute of Technology Palakkad, Palakkad, Kerala 678 557, India.
Chemotherapy is a crucial cancer treatment, but its effectiveness requires precise monitoring of drug concentrations in patients. This study introduces an innovative electrochemical strip sensor design to detect and continuously monitor methotrexate (MTX), a key chemotherapeutic drug. The sensor is crafted through an eco-friendly synthesis process that produces porous reduced graphene oxide (PrGO), which is then integrated with gold nanocomposites and polypyrrole (PPy) to boost the performance of a screen-printed carbon electrode (SPCE).
View Article and Find Full Text PDFAnal Chim Acta
January 2025
Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, Jinan University, Guangzhou, 510632, China. Electronic address:
Background: The multifunctional cytokine interleukin-6 (IL-6) plays a pivotal role in chronic and acute inflammatory responses, underscoring the importance of accurately determining IL-6 levels for early diagnosis, prevention, and treatment of inflammation.
Results: This study developed a versatile and innovative single-particle surface-enhanced Raman spectroscopy (SERS) sensing platform for the precise and sensitive quantification of IL-6 in complex samples using a novel one-pot synthesized, silver ions-doped three-dimensional porous gold microparticles (PGMs) with abundant hot spots for robust SERS enhancement. By rationally designing rich cytosine-Ag-cytosine base pairs between IL-6 aptamers and complementary chains on the PGMs, we harnessed the SERS-enhancing effect to achieve highly sensitive and specific IL-6 quantification within a wide range of 10 to 10 mg/mL and a limit of detection (LOD) of 0.
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