In vitro selection of a trans aptamer complex for target-responsive fluorescence activation.

Background: Most biological molecular complexes consist of multiple functional domains, yet rationally constructing such multifunctional complexes is challenging. Aptamers, the nucleic acid-based functional molecules, can perform multiple tasks including target recognition, conformational changes, and enzymatic activities, while being chemically synthesizable and tunable, and thus provide a basis for engineering enhanced functionalities through combination of multiple units. However, the conventional approach of simply combining aptamer units in a serial manner is susceptible to undesired crosstalk or interference between the aptamer units and to false interactions with non-target molecules; besides, the approach would require additional mechanisms to separate the units if they are desired to function independently.

Aptasensor-encapsulating semi-permeable proteinosomes for direct target detection in non-treated biofluids.

Detecting biomarkers in biofluids directly without sample treatments makes molecular diagnostics faster and more efficient. Aptasensors, the nucleic acid-based molecular biosensors, can detect a wide range of target molecules, but their susceptibility to degradation and aggregation by nucleases and charged proteins, respectively, limits their direct use in clinical samples. In this work, we demonstrate that when aptasensors are encapsulated in proteinosomes, the protein-based liposome mimics, clinically important small molecules can be sensitively and selectively detected in non-treated specimens, such as 100 % unpurified serum.

G-Quadruplex-Filtered Selective Ion-to-Ion Current Amplification for Non-Invasive Ion Monitoring in Real Time.

Living cells efflux intracellular ions for maintaining cellular life, so intravital measurements of specific ion signals are of significant importance for studying cellular functions and pharmacokinetics. In this work, de novo synthesis of artificial K -selective membrane and its integration with polyelectrolyte hydrogel-based open-junction ionic diode (OJID) is demonstrated, achieving a real-time K -selective ion-to-ion current amplification in complex bioenvironments. By mimicking biological K channels and nerve impulse transmitters, in-line K -binding G-quartets are introduced across freestanding lipid bilayers by G-specific hexylation of monolithic G-quadruplex, and the pre-filtered K flow is directly converted to amplified ionic currents by the OJID with a fast response time at 100 ms intervals.

Lead-start isothermal polymerase amplification controlled by DNAzymatic switches.

As DNA polymerases are even active at ambient temperature, there is inevitable non-specific amplification; to avoid the undesired amplification of analytes, a heat activation-based polymerase chain reaction (PCR), called hot-start PCR, is widely used to be highly precise and quantitative in detection. Unlike thermocycling amplification, isothermal amplification, compatible for point-of-care (PoC) tests, cannot be benefited by the heat-activation technique, making the method qualitative rather than quantitative. In this work, we newly developed a lead ion (Pb) activation technique, called lead-start isothermal amplification, allowing on-demand activation or deactivation of DNA polymerases at room temperature.

Osmotically balanced, large unilamellar liposomes that enable sustained bupivacaine release for prolonged pain relief in in vivo rat models.

To efficiently prolong analgesic effects, we developed osmotically balanced, large unilamellar liposomes (~ 6 μm in diameter) in which highly concentrated bupivacaine (up to 30 mg/mL) was encapsulated, and their sustained bupivacaine release was highly effective in relieving postoperative pain over 24 h in a rat model. Our reverse-phase evaporation method based on non-toxic alcohol, ethanol, enabled simple and cost-effective production of bupivacaine-loaded liposomes, of which osmotic pressure was readily balanced to improve the structural stability of the enlarged unilamellar liposomes along with extension of their shelf life (> a month). The in vitro release profile verified that the release duration of the bupivacaine-loaded liposomes extended up to 6 days.