Nanostraw membrane stamping for direct delivery of molecules into adhesive cells.

Delivering ions and molecules into living cells has become an important challenge in medical and biological fields. Conventional molecular delivery, however, has several issues such as physical and chemical damage to biological cells. Here, we present a method of directly delivering molecules into adhesive cells with an Au-based nanostraw membrane stamp that can physically inject a target molecule into the cytoplasm through a nanostraw duct. We successfully delivered calcein target molecules into adhesive cells with high efficiency (85%) and viability (90%). Furthermore, we modeled the molecular flow through Au nanostraws and then demonstrated the control of calcein flow by changing the concentration and geometry of Au nanostraws. Our Au membrane stamping provides a new way of accessing the cytoplasm to modulate cellular functions via injected molecules.

Synthesis of a Peptide-Human Telomere DNA Conjugate as a Fluorometric Imaging Reagent for Biological Sodium Ion.

A peptide-oligonucleotide conjugate (1) was synthesized by the attachment of FAM, TAMRA, and biotin moieties to a telomere DNA sequence of 5'-TAG GGT TAG GGT TAG GGT TAG GG-3'. This conjugate was induced to be an anti-parallel structure in the presence of sodium ion (Na+), whereas a hybrid one was formed under potassium ion (K+) as a monitoring by circular dichromic spectra. The conformation change of this conjugate gave an effective FRET signal change upon the addition of NaCl, compared with the case of KCl. Under 5 mM KCl as an extracellular condition, a FRET change was observed upon addition of NaCl and quantitative FRET change was observed in 0 - 250 mM NaCl. This conjugate was immobilized on the cell surface through a sugar chain on the cell, biotinyl concanavallin A and streptavidin. This conjugate was utilized for Na+ sensing based on anti-parallel tetraplex formation with Na+.

Enhancement of adipogenesis induction by conditioned media obtained from cancer cells.

White adipose tissue is a multifunctional endocrine organ that synthesizes and secretes cytokine-like proteins termed adipokines. In the present study, the effects of cancer-derived medium on adipogenesis were examined. We prepared conditioned media from cancer cell lines, and cultured preadipocytes in the conditioned media. After 10 days of culture, intracellular lipid droplet accumulation was measured. We observed that the conditioned media significantly induced adipogenesis or enhanced the adipogenesis induced by adipogenesis inducers. Although we could not define the factors, these undefined factors derived from cancer cells may induce adipogenesis, and the resulting adipogenesis may affect cancer development.