Effects of tea oil camellia (Camellia oleifera Abel.) shell-based organic fertilizers on the physicochemical property and microbial community structure of the rhizosphere soil.

Soil microorganisms play important roles in promoting soil ecosystem restoration, but much of the current research has been limited to changes in microbial community structure in general, and little is known regarding the soil physicochemical property and microbial community structure. In this study, four organic fertilizers were first prepared based on tea oil camellia shell (TOCS). Our findings indicate that the application of BOFvo increased both total pore volume and BET surface area of the rhizosphere soils, as well there was a remarkable enhancement in total organic matter (TOM), total nitrogen (TN), available nitrogen (AN), total phosphorus (TP), total potassium (TK), and available potassium (AK) contents of the rhizosphere soils. Meanwhile, in comparison to the CK and CF groups, the utilization of BOFvo led to a substantial increase in both average yield and fruiting rate per plant at maturity, as well resulted in a significant increase in TN and TP contents of tea oil camellia leaves. Furthermore, our findings suggest that the application of TOCS-based organic fertilizers significantly enhances the microbial diversity in the rhizosphere soils with Proteobacteria and Ascomycota being the dominant bacterial and fungal phyla, respectively, and Rhodanobacter and Fusarium being the dominant bacterial and fungal genus, respectively. Redundancy analysis (RDA) indicates that the physicochemical characteristics of TOCS-based organic fertilizers had a significant impact on the composition and distribution of microbial communities in the rhizosphere soils. This study will facilitate the promotion and application of TOCS-based organic fertilizers, thereby establishing a foundation for the reuse of tea oil camellia waste resources.

Sensitive and rapid determination of heat shock protein 70 using lateral flow immunostrips and upconversion nanoparticle fluorescence probes.

Heat shock protein 70 (Hsp70), belonging to the heat shock protein (HSP) family, is reported to be a potential diagnostic biomarker. In this work, a lateral flow immunostrip was fabricated for the sensitive and rapid determination of Hsp70 by the incorporation of fluorescence and upconversion nanoparticle probes. The upconversion nanoparticles (UCNPs, size ∼39 nm, λex = 980 nm; λem = 540 nm) consisting of a NaYF4:Yb/Er core and polyacrylic acid-modified shell were covalently coupled with Hsp70 antibodies to form the signal probe, which was characterized by dynamic light scattering and zeta potential analyses. The lateral flow assay (LFA) was constructed based on the sandwich-type immunoassay using a sample pad, a test pad, and an adsorption pad on a PVP backing. Hsp70 antibody, IgG antibody and the signal probe were separately dropped on the test zone, the control zone of the test pad, and the sample pad, respectively. In the sandwich LFA, since two antibodies bind to Hsp70 antigenic epitopes, i.e. specific binding, it provided superior specificity and high sensitivity, making it an ideal sensing platform for complex samples like serum Hsp70 samples. The important parameters for the preparation of the lateral flow immunostrips were optimized. Under the optimized conditions, Hsp70 can be detected using the increased fluorescence intensity of UCNPs with a wide linear range from 0.11 to 12 ng mL-1, low detection limit of 0.06 ng mL-1, small sample volume (120 µL), short assay time (15 min) and good reproducibility. The fluorescence method was successfully applied in the determination of Hsp70 in serum samples with good recovery. By combining the accessibility of the lateral flow immunostrips and upconversion nanoparticles, the fluorescence method can serve as a point-of-care testing method for protein assays with high sensitivity and fast detection.

Lateral flow immunostrips for the sensitive and rapid determination of 8-hydroxy-2'-deoxyguanosine using upconversion nanoparticles.

Lateral flow immunostrips were newly designed and a sensitive and rapid fluorometric method for the determination of 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a model target of small biomarker molecules was developed. The upconversion nanoparticles (UCNPs, NaYF4:Yb/Er core, and polyacrylic acid (PAA)-modified shell, size ~ 39 nm, excitation wavelength = 980 nm; emission wavelength = 540 nm) were employed as fluorescence signal material. The 8-OHdG antibody (Ab) was taken as the recognition probe while UCNP-labeled Ab was taken as the signal probe. Bovine serum albumin (BSA) was designed as carrier protein for 8-OHdG to form 8-OHdG-BSA conjugate as the capture probe. The lateral flow immunostrips were prepared by laminating a sample pad (glass fiber membrane), a test pad (nitrocellulose membrane), and adsorption pad (filter paper) on PVP backing. The capture probe was immobilized on the test zone while an IgG antibody taken as the control probe was immobilized on the control zone. When the signal probe and the sample were in sequence loaded on the sample pad, 8-OHdG analyte bound with the signal probe, and then the excess of the signal probe move along the strip and is collected by the capture probe on the test zone while the remnant signal probe is collected by the control probe on the control zone. The signal probe and capture probe were synthesized and characterized. The fluorescence intensity on the test zone was inversely proportional to the concentration of 8-OHdG for the quantitative determination while the fluorescence emission on the control zone was observed to validate the assay. The developed method showed a wide linear range from 0.10 to 10 nM, a quite low detection limit of 0.05 nM, small sample volume requirement (100 µL), short assay time (15 min), and good method reproducibility (RSD = 4.4%, nine immunostrips). Graphical abstract Schematic illustration of the configuration and measurement principle of lateral flow fluorescence immunostrip for 8-OHdG: (a) configuration; (b) preparation: load of capture probe (BSA-8-OHdG, 2 µL) on test zone; load of control probe (IgG Ab, 2 µL) on control zone; load of signal probe (UCNP-Ab, 16 µL) on sample pad; (c) measurement: load of sample (8-OHdG, 100 µL) on sample pad, collection, and measurement.