Plasma Levels of Complement Factor I and C4b Peptides Are Associated with HIV Suppression.

Individuals who exhibit long-term HIV suppression and CD4 T-cell preservation without antiretroviral therapy are of great interest for HIV research. There is currently no robust method for rapid identification of these "HIV controller" subjects; however, HLA-B*57 (human leukocyte antigen (major histocompatibility complex), class I, B*57) genotype exhibits modest sensitivity for this phenotype. Complement C3b and C4b can influence HIV infection and replication, but studies have not examined their possible link to HIV controller status. We analyzed HLA-B*57 genotype and complement levels in HIV-positive patients receiving suppressive antiretroviral therapy, untreated HIV controllers, and HIV-negative subjects to identify factors associated with HIV controller status. Our results revealed that the plasma levels of three C4b-derived peptides and complement factor I outperformed all other assayed biomarkers for HIV controller identification, although we could not analyze the predictive value of biomarker combinations with the current sample size. We believe this rapid screening approach may prove useful for improved identification of HIV controllers.

Facile synthesis of 5 nm NaYF4:Yb/Er nanoparticles for targeted upconversion imaging of cancer cells.

5nm intense green emission NaYF4:Yb/Er upconversion nanoparticles (UCNPs) with pure ß phase was synthesized with a simple "green" strategy for the first time. Traditional organic solvothermal method is often applied to prepare the high-quality and uniform UCNPs, but the preparation of lanthanide-oleate complexes is laborious as heating and multistep post-treatment for purification are often required. The water-alcohols solvothermal method is environmentally friendly, but the fabricated UCNPs have big size, poor biocompatibility and high cytotoxicity, which limited their application for cell imaging. Herein, NaYF4:Yb/Er UCNPs were prepared with rare-earth nitrates RE(NO3)3 (RE=Y0.80 Yb0.18 Er0.02) as precursors and diethylene glycol (DEG)/ethylene glycol (EG)/water as the solvent. A facile green solvothermal method with the temperature being controlled at 300°C was developed. The as-prepared NaYF4:Yb/Er UCNPs were characterized and were found to have enhanced UC emission and controllable particle size. The as-prepared UCNPs were further functionalized via folic acid coating for the targeted imaging and improved bio- compatibility. It was made the UCNPs potential for upconversion bioimaging of living cells by the strong upconversion luminescence, the excellent biocompatibility, and the super-small size. The good colloidal stability and low cell cytotoxicity of the as-prepared UCNPs and the developed synthesis protocol might advance both the fields of UCNPs and biomolecule-based nanotechnology for future studies.

Bioconjugated persistent luminescence nanoparticles for Föster resonance energy transfer immunoassay of prostate specific antigen in serum and cell extracts without in situ excitation.

A novel Föster resonance energy transfer (FRET) immunoassay based on persistent luminescence nanoparticles (PLNP) was established for prostate specific antigen (PSA) detection in serum and cell extracts without in situ excitation. The specific FRET behavior allows highly selective and sensitive ratiometric photoluminescent detection of PSA in biological samples.

Silica-coated S(2-)-enriched manganese-doped ZnS quantum dots as a photoluminescence probe for imaging intracellular Zn2+ ions.

Detection of intracellular Zn(2+) has gained great attention because of its biological significances. Here we show the fabrication of silica-coated S(2-)-enriched Mn-doped ZnS quantum dots (SiO(2)-S-Mn-ZnS QDs) by enriching S(2-) with a silica shell on the surface of Mn-doped ZnS QDs via a sol-gel process for imaging intracellular Zn(2+) ions. The developed probe gave a good linearity for the calibration plot (the recovered PL intensity of the SiO(2)-S-Mn-ZnS QDs against the concentration of Zn(2+) from 0.3 to 15.0 µM), excellent reproducibility (1.2% relative standard deviation for 11 replicate measurements of Zn(2+) at 3 µM), and low detection limit (3s; 80 nM Zn(2+)). The SiO(2)-S-Mn-ZnS QDs showed negligible cytotoxicity, good sensitivity, and selectivity for Zn(2+) in a photoluminescence turn-on mode, being a promising probe for photoluminescence imaging of intracellular Zn(2+).

Fluorescence resonance energy transfer inhibition assay for α-fetoprotein excreted during cancer cell growth using functionalized persistent luminescence nanoparticles.

Persistent-luminescence nanoparticles (PLNPs) are promising as a new generation of photoluminescent probes for detection of biomolecules and bioimaging. Here we report a fluorescence resonance energy transfer (FRET) inhibition assay for α-fetoprotein (AFP) excreted during cancer cell growth using water-soluble functionalized PLNPs based on Eu2+- and Dy3+-doped Ca1.86Mg0.14ZnSi2O7. Polyethyleneimine-coated PLNPs were conjugated with AFP-antibody-coated gold nanoparticles as a sensitive and specific persistent photoluminescence probe for detection of AFP in serum samples and imaging of AFP excreted during cancer cell growth. Such PLNPs do not contain toxic heavy metals. Their long-lasting afterglow nature allows detection and imaging without external illumination, thereby eliminating the autofluorescence and scattering light from biological matrixes encountered under in situ excitation.