A Biostable l-DNA Hydrogel with Improved Stability for Biomedical Applications.

DNA hydrogels have attracted increasing attention owing to their excellent permeability and high mechanical strength, together with thixotropy, versatile programmability and good biocompatibility. However, the moderate biostability and immune stimulation of DNA have arisen as big concerns for future potential clinical applications. Herein, we report the self-assembly of a novel l-DNA hydrogel, which inherited the extraordinary physical properties of a d-DNA hydrogel.

Precise pitch-scaling of carbon nanotube arrays within three-dimensional DNA nanotrenches.

Precise fabrication of semiconducting carbon nanotubes (CNTs) into densely aligned evenly spaced arrays is required for ultrascaled technology nodes. We report the precise scaling of inter-CNT pitch using a supramolecular assembly method called spatially hindered integration of nanotube electronics. Specifically, by using DNA brick crystal-based nanotrenches to align DNA-wrapped CNTs through DNA hybridization, we constructed parallel CNT arrays with a uniform pitch as small as 10.

In Situ Formation of Covalent Second Network in a DNA Supramolecular Hydrogel and Its Application for 3D Cell Imaging.

DNA hydrogels have been demonstrated with important applications in three-dimensional cell culture in vitro due to their good biocompatibility, biodegradability, and permeability. In these applications, to observe the cell morphology and functions in situ, immobilization, labeling, and imaging processes are involved, which requires good stability of the hydrogels during washing and immersion. To improve the stability of the hydrogels for better imaging, here we built a covalent second network in a DNA supramolecular hydrogel by in situ polymerization and successfully constructed a stable three-dimensional transparent system for cell culture and observation.

On the role of flexibility in linker-mediated DNA hydrogels.

Three-dimensional DNA networks, composed of tri- or higher valent nanostars with sticky, single-stranded DNA overhangs, have been previously studied in the context of designing thermally responsive, viscoelastic hydrogels. In this work, we use linker-mediated gels, where the sticky ends of two trivalent nanostars are connected through the complementary sticky ends of a linear DNA duplex. We can design this connection to be either rigid or flexible by introducing flexible, non-binding bases.

Microrheology of DNA hydrogels.

A key objective in DNA-based material science is understanding and precisely controlling the mechanical properties of DNA hydrogels. We perform microrheology measurements using diffusing wave spectroscopy (DWS) to investigate the viscoelastic behavior of a hydrogel made of Y-shaped DNA (Y-DNA) nanostars over a wide range of frequencies and temperatures. We observe a clear liquid-to-gel transition across the melting temperature region for which the Y-DNA bind to each other.

Tuning the Mechanical Properties of a DNA Hydrogel in Three Phases Based on ATP Aptamer.

By integrating ATP aptamer into the linker DNA, a novel DNA hydrogel was designed, with mechanical properties that could be tuned into three phases. Based on the unique interaction between ATP and its aptamer, the mechanical strength of the hydrogel increased from 204 Pa to 380 Pa after adding ATP. Furthermore, with the addition of the complementary sequence to the ATP aptamer, the mechanical strength could be increased to 570 Pa.

Self-Collapsing of Single Molecular Poly-Propylene Oxide (PPO) in a 3D DNA Network.

On the basis of DNA self-assembly, a thermal responsive polymer polypropylene oxide (PPO) is evenly inserted into a rigid 3D DNA network for the study of single molecular self-collapsing process. At low temperature, PPO is hydrophilic and dispersed uniformly in the network; when elevating temperature, PPO becomes hydrophobic but can only collapse on itself because of the fixation and separation of DNA rigid network. The process has been characterized by rheological test and Small Angle X-Ray Scattering test.

Research on highly sensitive optomagnetic sensor for rapid detection of inflammation.

Background: C-reactive protein (CRP) is used to evaluate the evolution of infections and sepsis in critically ill patients. For POCT testing, biosensor-based detection techniques offer quick and convenient application.

Objective: A prototype three dimensional chip was fabricated based on a new optomagnetic method to achieve the rapid detection of CRP.

Supramolecular Hydrogels Based on DNA Self-Assembly.

Extracellular matrix (ECM) provides essential supports three dimensionally to the cells in living organs, including mechanical support and signal, nutrition, oxygen, and waste transportation. Thus, using hydrogels to mimic its function has attracted much attention in recent years, especially in tissue engineering, cell biology, and drug screening. However, a hydrogel system that can merit all parameters of the natural ECM is still a challenge.

Remote Controlling DNA Hydrogel by Magnetic Field.

DNA hydrogel has aroused widespread attention because of its unique properties. In this work, the DNA-modified magnetic nanoparticles were integrated into the mainframe of DNA hydrogel, resulting in DNA-MNP hydrogel. Under the magnetic field, this hydrogel can be remotely deformed into various shapes, driven to jump between two planes and even climb the hill.

Responsive Double Network Hydrogels of Interpenetrating DNA and CB[8] Host-Guest Supramolecular Systems.

A supramolecular double network hydrogel is presented by physical interpenetration of DNA and cucurbit[8]uril networks. In addition to exhibiting an increase in strength and thermal stability, the double network hydrogel possesses excellent properties such as stretchability, ductility, shear-thinning, and thixotropy. Moreover, it is enzymatically responsive to both nuclease and cellulase, as well as small molecules, showing great potential as a new soft material scaffold.

An intelligent method for identifying otological drill slippage.

An otological drill is a fundamental apparatus used for bone-milling in ear surgery. A common problem in bone-milling is that the drill bit slips on the bone surface. To improve the operational safety of such a surgery, this article presents a new apparatus combined with an intelligent method for identifying drill slippage.

A method for identifying otological drill entanglement with a cotton swab.

Background: The entanglement of the otological drill with cotton swabs is a common milling fault in ear surgery. To improve operational safety, this paper presents a method for identifying this type of milling fault.

Methods: Force and current sensors were installed on a modified otological drill.

A method for identifying otological drill milling through bone tissue wall.

Background: Otological drill milling through the bone tissue wall is a common milling fault in ear surgery. This paper presents a method for identifying milling faults and improving operation safety.

Methods: Force and current sensors are used.

Automatic identification of otological drilling faults: an intelligent recognition algorithm.

Background: This article presents an intelligent recognition algorithm that can recognize milling states of the otological drill by fusing multi-sensor information.

Methods: An otological drill was modified by the addition of sensors. The algorithm was designed according to features of the milling process and is composed of a characteristic curve, an adaptive filter and a rule base.

Automatic identification of otologic drilling faults: a preliminary report.

Background: A preliminary study was carried out to identify parameters to characterize drilling faults when using an otologic drill under various operating conditions.

Methods: An otologic drill was modified by the addition of four sensors. Under consistent conditions, the drill was used to simulate three important types of drilling faults and the captured data were analysed to extract characteristic signals.