Development of an Indirect ELISA to Distinguish between Porcine Sapelovirus-Infected and -Vaccinated Animals Using the Viral Nonstructural Protein 3AB.

Porcine sapelovirus (PSV) is a new pathogen that negatively impacts the pig industry in China. Affected pigs experience severe diarrhea and even death. Vaccination is used to control disease outbreaks, and sensitive diagnostic methods that can distinguish infected animals from vaccinated animals (DIVA) are essential for monitoring the effectiveness of disease control programs. Tests based on the detection of the nonstructural protein (NSP) 3AB are reliable indicators of viral replication in infected and vaccinated animals. In this study, the recombinant PSV 3AB protein was expressed by a prokaryotic expression system, and an indirect ELISA method was established. Serum samples from healthy animals, immunized animals, and infected animals were evaluated. The ELISA method identified 3AB with high sensitivity (99.78%) and specificity (100.0%), and no cross-reaction was observed with serum antibodies against porcine reproductive and respiratory syndrome virus (PRRSV), infection with classical swine fever virus (CSFV), pseudorabies virus (PRV), bovine viral diarrhea virus (BVDV), porcine epidemic diarrhea virus (PEDV), or foot-and-mouth disease virus (FMDV). The ELISA method described here can effectively distinguish infected and vaccinated animals and is an important inexpensive tool for monitoring serum and controlling PSV.

A 3D Composited Flexible Sensor Based on Percolative Nanoparticle Arrays to Discriminate Coupled Pressure and Strain.

Flexible mechanical sensors based on nanomaterials operate on a deformation-response mechanism, making it challenging to discern different types of mechanical stimuli such as pressure and strain. Therefore, these sensors are susceptible to significant mechanical interference. Here, we introduce a multifunctional flexible sensor capable of discriminating coupled pressure and strain without cross-interference. Our design involves an elastic cantilever fixed on the pillar of the flexible main substrate, creating a three-dimensional (3D) substrate, and two percolative nanoparticle (NP) arrays are deposited on the cantilever and main substrate, respectively, as the sensing materials. The 3D flexible substrate could confine pressure/strain loading exclusively on the cantilever or main substrate, resulting in independent responses of the two nanoparticle arrays with no cross-interference. Benefitting from the quantum transport in nanoparticle arrays, our sensors demonstrate an exceptional sensitivity, enabling discrimination of subtle strains down to 1.34 × 10-4. Furthermore, the suspended cantilever with one movable end can enhance the pressure perception of the NP array, exhibiting a high sensitivity of -0.223 kPa-1 and an ultrahigh resolution of 4.24 Pa. This flexible sensor with multifunctional design will provide inspiration for the development of flexible mechanical sensors and the advancement of decoupling strategies.

Integrated Passive Sensing Chip for Highly Sensitive and Reusable Detection of Differential-Charged Nanoplastics Concentration.

In this work, a new type, highly sensitive, and reusable nanoplastics (NPs) microwave detection method is proposed, which can be used to rapidly analyze NPs with different surface charges and sizes. The effective dielectric constant of NPs varies according to the different concentrations, particle sizes, and surface charges of NPs in aqueous solution. The feasibility of the microwave method for differential-charged NPs detection is verified using a complementary split ring resonator sensor manufactured on a cost-effective printed circuit board, which shows a high sensitivity only for positively charged NPs (PS-NH2) detection. To achieve microwave detection of both positively and negatively charged NPs (PS-SO3H), a microscale spiral-coupled resonator sensing chip is manufactured through integrated passive technology, which demonstrates extremely low detection limits and high sensitivity for both PS-NH2 and PS-SO3H, with different concentrations, particle sizes, and charges. In addition, for NPs solution doped with methyl orange, the device can still perform stable measurements, overcoming the inability of traditional NPs molecular element determination and optical detection methods to detect NPs aqueous solution with organic matter doping and color presence. The proposed microwave detection method could also be extended to sensing detection for detecting other hazardous environmental substances.

In vitro and in vivo evaluation of antibacterial activity of polyhexamethylene guanidine (PHMG)-loaded TiO2 nanotubes.

Artificial joint replacement is an effective surgical method for treating end-stage degenerative joint diseases, but peripheral bacterial infection of prosthesis can compromise the effect of the surgery. Herein, antibacterial effects of titanium dioxide nanotubes (TNTs) coated with polyhexamethylene guanidine (PHMG) were examined via in vitro and in vivo experiments. TNTs with a pore diameter 46.4 ± 5.9 nm and length of 300-500 nm for the slice and 650-800 nm for the rod were fabricated by anodization. Then, 3.46 ± 0.40 mg and 1.27 ± 0.28 mg of PHMG were coated onto the TNT slice and rod, respectively. In vitro studies of the release of PHMG showed that the antibacterial agent was released in two stages: initial burst release and relatively slow release. In vitro and in vivo antibacterial studies showed that the PHMG-loaded TNTs (PHMG-TNTs) had excellent antibacterial abilities to prevent bacterial infections. Clinical pathological analysis of rabbit femurs indicated that the implanted PHMG-TNTs had no apparent pathological changes. Real-time quantitative reverse transcription polymerase chain reaction analysis of the femur tissues around the implants showed that the expression of osteogenic-related genes, including runt-related transcription factor 2, osteocalcin, alkaline phosphatase, bone sialoprotein, bone morphogenetic protein 2 and vascular endothelial growth factor A, was significantly upregulated in the PHMG-TNT implanted group as compared to the other groups. Overall, these findings provide a promising approach for the fabrication of antibacterial and bone biocompatible titanium-based implants in orthopedics.