Conventional polyacrylamide (PAM) microspheres suffer from rapid uncontrolled swelling, poor temperature/salt resistance, and severe shear fragmentation, which greatly restrict their application in in-depth profile control and water shutoff of complex oil reservoirs. Herein, novel interpenetrating network microspheres (IPN-PAM/STA) were successfully fabricated via reverse emulsion polymerization, using polyacrylamide (PAM) as the primary network and acid-modified starch (STA) as the secondary crosslinking network. Structural characterizations including FTIR, XRD, TGA and DSC verified the successful construction of stable IPN structures, in which the crystalline structure of starch was completely transformed into an amorphous state through hydrogen-bonding interactions with PAM chains. Benefiting from the synergistic dual-network effect, the optimized IPN-PAM/STA microspheres exhibited controllable swelling behavior, structural integrity maintained above 70 °C, and favorable size stability under variable salinity and pH conditions. Core flooding tests demonstrated an ultra-high plugging efficiency of 96.3
Titanium dioxide nanoparticles (TiO₂ NPs), widely used as inorganic UV filters, tend to agglomerate, compromising formulation stability and often requiring relatively high surfactant concentrations. In the present work, surface-engineered TiO₂ NPs were repositioned as interfacial Pickering stabilizers to formulate stable oil-in-water emulsions, with surfactant primarily serving as a surface-modifying agent. Surface charge was altered through pH adjustment and surfactant adsorption, and the effects of pH, surfactant type, and surfactant-to-TiO₂ ratio were systematically investigated. Zeta-potential (ZP) analysis identified pH 3 and 0.15 wt
Abnormal levels of the non-metalloprotein bovine serum albumin (BSA) and the polyamine spermidine are associated with adverse biological effects, highlighting the need for their sensitive detection. Here, two binary ensembles, PYR@CTAB and PYR@SDS, were developed by encapsulating 1,8-naphthalimide possessing Schiff base (PYR) within cationic cetyltrimethylammonium bromide (CTAB) and anionic sodium dodecyl sulfate (SDS) micelles, respectively. The formed ensembles were characterized using dynamic light scattering (DLS), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), and optical techniques. Distinct fluorescence responses of PYR@CTAB and PYR@SDS were observed in the presence of BSA and spermidine, respectively, arising primarily from charge-mediated interactions between the probes and analytes. The detection limits for BSA and spermidine were determined to be 0.05 and 7.74 µM, respectively. The practical applicability of the sensing platforms was demonstrated through reliable quantification of BSA and spermidine in packaged milk and human serum samples, with recoveries ranging from 98.1 to 105.5
The rational design of metal-semiconductor interfaces is crucial for overcoming the limitation of charge carrier recombination in TiO₂-based photocatalysis. Herein, we construct a Cu–O–Ti bridged heterostructure by anchoring Cu/TiO₂ nanoparticles onto biodegradable poly-β-hydroxybutyrate (PHB) microspheres. The optimized catalyst, (Cu₇.₅/TiO₂)₁₂@PHB, achieved a 93.5
In this study, we have conducted a comparative investigation of the interactions of bovine serum albumin (BSA) with a bisquaternary ammonium salt (BQAS) and its monomeric counterpart, dodecyltrimethylammonium bromide (DTAB), by using isothermal titration calorimetry (ITC), fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and molecular docking. ITC measurements showed that BSA has only one binding site for BQAS (N = 0.98 ± 0.28), but multiple binding sites for DTAB (N = 2.38 ± 0.30). The interaction mechanisms of BSA with BQAS and DTAB are similar, as both are enthalpy-driven spontaneous exothermic processes. However, the binding constant of DTAB [(2.38 ± 0.46) × 104 M− 1] is higher than that of BQAS [(1.87 ± 0.25) × 104 M− 1], and the enthalpy change of DTAB (-36.32 ± 5.96 kJ·mol− 1) is also more negative than that of BQAS (-26.84 ± 8.48 kJ·mol− 1). The spectroscopic results from fluorescence and CD measurements indicated that both surfactants bind to the BSA surface, inducing only minor conformational changes in the protein. Molecular docking suggested that DTAB may bind to three distinct negatively charged surface regions on BSA through electrostatic interactions, while BQAS was predicted to bind to only one of these regions. Overall, the two hydrophobic tails of BQAS may enhance the hydrophobicity of the molecule, introduce greater steric hindrance, and possibly reduce the interaction between BQAS and BSA.
