► Super‐resolution single‐particle tracking of immune receptors. ► FcεRI receptors maintain lateral mobility inside receptor clusters. ► FcεRI receptor immobilization is not required for signaling. ►...

Induced pluripotent stem cells are usually derived by reprogramming transcription factors (OSKM), such as octamer-binding transcription factor 4 (OCT4), (sex determining region Y)-box 2 (SOX2), Krüppel-like factor 4 (KLF4), and cellular proto-oncogene (c-Myc). However, the genomic integration of transcription factors risks the insertion of mutations into the genome of the target cells. Recently, the clustered regularly interspaced short palindromic repeat-associated protein 9 (CRISPR/Cas9) system has been used to edit genomes. In this work, dCas9-VPR (dCas9 with a gene activator, VP64-p65-Rta (VPR), fused to its c-terminus) and guide RNA (gRNA) combined to form ribonucleoproteins, which were immobilized on magnetic peptide-imprinted chitosan nanoparticles. These were then used to activate OSKM genes in human embryonic kidney (HEK) 293T cells. Four pairs of gRNAs were used for the binding site recognition to activate the OSKM genes. Transfected HEK293T cells were then prescreened for the high expression of OSKM proteins by immunohistochemistry images. The optimal gRNAs for OSKM expression were identified using quantitative real-time polymerase chain reaction and the staining of OSKM proteins. Finally, we found that the activated expression of one of the OSKM genes is up to three-fold higher than that of the other genes, enabling precise control of the cell differentiation.

Molecularly imprinted polymers (MIPs) can often bind target molecules with high selectivity and specificity. When used as MIPs, conductive polymers may have unique binding capabilities; they often contain aromatic rings and functional groups, which can undergo π-π and hydrogen bonding interactions with similarly structured target (or template) molecules. In this work, an electrochemical method was used to optimize the synthetic self-assembly of poly(aniline-co-metanilic acid) and testosterone, forming testosterone-imprinted electronically conductive polymers (TIECPs) on sensing electrodes. The linear sensing range for testosterone was from 0.1 to 100 pg/mL, and the limit of detection was as low as ~pM. Random urine samples were collected and diluted 1000-fold to measure testosterone concentration using the above TIECP sensors; results were compared with a commercial ARCHITECT ci 8200 system. The testosterone concentrations in the tested samples were in the range of 0.33 ± 0.09 to 9.13 ± 1.33 ng/mL. The mean accuracy of the TIECP-coated sensors was 90.3 ± 7.0%.

Programmed cell death protein 1 (PD-1) is a biomarker on the surface of cells with a role in promoting self-tolerance by suppressing the inflammatory activity of T cells. In this work, one peptide of PD-1 was used as the template for molecular imprinting to form magnetic peptide-imprinted poly(ethylene-co-vinyl alcohol) composite nanoparticles (MPIP NPs). The nanoparticles were characterized by dynamic light scattering (DLS), high-performance liquid chromatography (HPLC), Brunauer–Emmett–Teller (BET) analysis, and superconducting quantum interference device (SQUID) analysis. Natural killer 92 (NK-92) cells were added to these composite nanoparticles and then incubated with human hepatoma (HepG2) cells. The viability and the apoptosis pathway of HepG2 were then studied using cell counting kit-8 (CCK8) and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. These nanoparticles were found to significantly enhance the activity of natural killer cells toward HepG2 cells by increasing the expression of nuclear factor kappa B (NF-κB), caspase 8, and especially caspase 3.