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Silver nanoparticles (AgNPs) are one of the most widely used antimicrobial agents. However, due to the potential problems of environmental pollution and high energy consumption, a green and efficient synthesis strategy of AgNPs is urgently required. Ovalbumin (OVA) is the most abundant protein in egg whites, and its extraction process is simple and productive. This paper reported a new green synthesis method of AgNPs by using OVA as an assistant accompanying with a visible light irradiation. Together with the reduction of silver ions, the uniformly dispersed OVA‐AgNPs nanocomposite could be formed within 30 min under xenon light irradiation by simple mixing AgNO3 and OVA in aqueous solution. The detailed mechanism study showed that tyrosine residue and peptide bonds in OVA played a major role in the reduction and stability of silver ions. In addition, in vitro antibacterial experiments indicated that 10 mg/L of OVA‐AgNPs, the minimum inhibitory concentration, has a good antimicrobial effect on both Gram‐positive and Gram‐negative bacteria, fungi, and some drug‐resistant bacteria species within 4 h of treatment, mainly due to the disruption of the structure of bacterial cell and the balance of reactive oxygen species. This work provides a new way for the green and efficient synthesis of AgNPs and shows good prospects for the applications in the field of biomedical materials and functional nanomaterials. [ABSTRACT FROM AUTHOR]

The use of natural proteins is a green and effective method for synthesizing silver nanoparticles (AgNPs). Aromatic amino acids of proteins play a reducing role in synthesis, and proteins are coated on the surface of AgNPs to play the role of stabilizers. In this study, we developed an efficient one-step method for synthesizing AgNPs using lysozyme (LYZ) under visible-light irradiation from a xenon lamp in situ. The light conditions and LYZ structure could substantially affect the synthesis. Antibacterial and scald-wound healing results showed that LYZ/AgNPs had broad-spectrum and efficient antibacterial activity and promoted scald-wound healing. Therefore, the proposed synthesis method and LYZ/AgNPs have good practical application prospects. [ABSTRACT FROM AUTHOR]

It is widely believed that high-purity protein is critical to crystallization. Impurities can induce lattice strain, internal stress, and rotation disorder, thus decreasing protein crystallization success rate and crystal quality. However, some studies showed that protein could be crystallized from impure solutions; thus, the effect of impurities on protein crystallization remains unclear. Here, we systemically studied the effect of impurity type and concentration on protein crystallization. Results showed that protein crystallization was different when using different impurities. Protein crystallization could be promoted with a low concentration of impurities and inhibited with a high concentration of impurities, and this inhibition can be weakened by an audible sound. The effect of impurities on protein crystallization can be explained by the phase separation theory. In summary, we suggest that proper impurities might be beneficial to enhance protein crystallization. [ABSTRACT FROM AUTHOR]

A sample delivery system is one of the key parts of serial crystallography. It is the main limiting factor affecting the application of serial crystallography. At present, although a variety of useful sample delivery systems have been developed for serial crystallography, it still remains the focus of the field to further improve the performance and efficiency of sample delivery. In existing sample delivery technologies, samples are usually delivered in linear motion. Here we show that the samples can also be delivered using circular motion, which is a novel motion mode never tested before. In this paper, we report a microfluidic rotating-target sample delivery device, which is characterized by the circular motion of the samples, and verify the performance of the device at a synchrotron radiation facility. The microfluidic rotating-target sample delivery device consists of two parts: a microfluidic sample plate and a motion control system. Sample delivery is realized by rotating the microfluidic sample plate containing in situ grown crystals. This device offers significant advantages, including a very wide adjustable range of delivery speed, low background noise, and low sample consumption. Using the microfluidic rotating-target device, we carried out in situ serial crystallography experiments with lysozyme and proteinase K as model samples at the Shanghai Synchrotron Radiation Facility, and performed structural determination based on the serial crystallographic data. The results showed that the designed device is fully compatible with the synchrotron radiation facility, and the structure determination of proteins is successful using the serial crystallographic data obtained with the device. [ABSTRACT FROM AUTHOR]

Synthesis of silver nanoparticles (AgNPs) with desired physicochemical properties using a cost-effective, energy, and time efficient way is vital. In this study, we have optimized the synthesis of AgNPs through protein containing cell-free supernatant of Enterobacter cloacae (SMP1). 23 full factorial central composite design (CCD) of the response surface methodology (RSM) was used for the process optimization. Individual and mutual interaction effects of the experimental variables including temperature, pH, inoculum size, and metal concentration were investigated on the synthesis of AgNPs. Results showed the involvement of 15 kDa protein in the synthesis of AgNPs. The optimized values of pH, temperature, cell-free culture supernatant (CFCS), and metal concentration were 10, 37 °C, 10% (v/v) and 2 mM, respectively. Characterization of AgNPs using UV-Vis spectroscopy reveals surface plasmon resonance peak at 450 nm. AFM and TEM micrographs revealed oval and spherical shaped AgNPs with the size of spherical (15–44 nm) and oval (20–46 nm wide and 240–325 nm long) and zeta potential of −41.3 mV under different experimental conditions. The EDS, X-ray elemental mapping, and FTIR reviled the presence of metallic AgNPs and signatures for nitrogen, carbon, oxygen, sulfur, and functional groups of different biomolecules. [ABSTRACT FROM AUTHOR]

Objective: Magnetic drug targeting (MDT) has attracted a lot of attention in recent years as a treatment to reduce side effects and improve efficacy. To realize successful MDT, a magnet system that can create suitable magnetic field is necessary. However, the existing technology has some shortcomings such as low targeting efficiency and unsatisfactory targeting effect. The method of using time-varying magnetic field proposed in this paper provides a new solution to this problem. Methods: In this work, a permanent magnet system providing rotational magnetic field (a time-varying magnetic field) was designed and constructed. Focusing experiments of Fe3O4 particles were carried out in this system, and the mechanism of the focusing was discussed via a simplified model. Results: By using the rotational magnetic field, superparamagnetic Fe3O4 particles can be successfully driven to the designated site within a short time. Our work showed that the time-varying magnetic field can drive the superparamagnetic particles to a focusing site, which is not possible under the same magnetic field without rotation, and the aggregation speed and effect are better than those under static field. Conclusion and Significance: Our results indicate that time-varying magnetic field can be a good choice for designing magnet systems for MDT. Moreover, the idea of using time-varying magnetic field for focusing superparamagnetic particles may be applicable in non-contact processings or manipulations of paramagnetic, superparamagnetic, or even ferromagnetic materials or objects in preparation of novel materials, robotic control of objects, and so on. [ABSTRACT FROM AUTHOR]