Microtia is a congenital external ear malformation that can seriously influence the psychological and physiological well-being of affected children. The successful regeneration of human ear-shaped cartilage using a tissue engineering approach in a nude mouse represents a promising approach for auricular reconstruction. However, owing to technical issues in cell source, shape control, mechanical strength, biosafety, and long-term stability of the regenerated cartilage, human tissue engineered ear-shaped cartilage is yet to be applied clinically. Using expanded microtia chondrocytes, compound biodegradable scaffold, and in vitro culture technique, we engineered patient-specific ear-shaped cartilage in vitro. Moreover, the cartilage was used for auricle reconstruction of five microtia patients and achieved satisfactory aesthetical outcome with mature cartilage formation during 2.5 years follow-up in the first conducted case. Different surgical procedures were also employed to find the optimal approach for handling tissue engineered grafts. In conclusion, the results represent a significant breakthrough in clinical translation of tissue engineered human ear-shaped cartilage given the established in vitro engineering technique and suitable surgical procedure.This study was registered in Chinese Clinical Trial Registry (ChiCTR-ICN-14005469).

This paper reports the finding of the superior auricular artery, which is a fairly large arterial branch, about 1 mm in diameter, arising from the superficial temporal artery anterior to the auricular helix. It is covered by skin, the anterior auricular muscle, and the fascia of the parotid gland. It runs together with its concomitant vein posteriorly in the groove between the cartilage of the ear and the temporal bone and anastomoses with the posterior auricular artery. This artery has been used successfully to raise large retroauricular arterial island flaps for one case of total nose reconstruction and seven cases of reconstruction of the severely constricted anophthalmic socket. These operative procedures are described in detail.

We report on the development of a vertical and transparent microfluidic chip for high-throughput phenotyping of Arabidopsis thaliana plants. Multiple Arabidopsis seeds can be germinated and grown hydroponically over more than two weeks in the chip, thus enabling large-scale and quantitative monitoring of plant phenotypes. The novel vertical arrangement of this microfluidic device not only allows for normal gravitropic growth of the plants but also, more importantly, makes it convenient to continuously monitor phenotypic changes in plants at the whole organismal level, including seed germination and root and shoot growth (hypocotyls, cotyledons, and leaves), as well as at the cellular level. We also developed a hydrodynamic trapping method to automatically place single seeds into seed holding sites of the device and to avoid potential damage to seeds that might occur during manual loading. We demonstrated general utility of this microfluidic device by showing clear visible phenotypes of the immutans mutant of Arabidopsis, and we also showed changes occurring during plant-pathogen interactions at different developmental stages. Arabidopsis plants grown in the device maintained normal morphological and physiological behaviour, and distinct phenotypic variations consistent with a priori data were observed via high-resolution images taken in real time. Moreover, the timeline for different developmental stages for plants grown in this device was highly comparable to growth using a conventional agar plate method. This prototype plant chip technology is expected to lead to the establishment of a powerful experimental and cost-effective framework for high-throughput and precise plant phenotyping.

This paper reports on a microfluidic Impedimetric nitrate sensor using graphene oxide (GO) nanosheets enabled poly(3,4-ethylenedioxythiophene) nanofibers (PEDOT-NFs) as an electrochemical working electrode. The sensor has demonstrated its capability to detect nitrate ions in real samples extracted from soil. The PEDOT NFs-GO composite serves as an effective matrix for immobilization of nitrate reductase enzyme molecules. The oxygenated functional groups available at GO allows increasing the charge transfer resistance of the PEDOT NFs-GO based electrode. Systematic microscopic, spectroscopic, and electrochemical studies were conducted to illustrate synergic interactions between the GO and PEDOT NFs. The sensor provides a sensitivity of 61.15 Ω/(mg/L)/cm 2 within a concentration range of 0.44 − 442 mg/L for nitrate ions. The detection limit of the sensor is 0.135 mg/L with good specificity, reliability, and reproducibility.

It is challenging to integrate porous graphene foam (GF) and GF-based nanocomposites into microfluidic channels and even create microfluidic structures within these materials. This is because their irregular interior pore shape and geometry, rough exterior surface, and relatively large material thickness make it difficult to perform conventional photolithography and etching. This challenge has largely hindered the potential of using GF-based materials in microfluidics-based sensors. Here we present a simple approach to create well-defined flow-through channels within or across the GF-based materials, using a liquid-phase photopolymerization method. This method allows embedding of a nanocomposite-based scaffold of GF and titanium nitride nanofibers (GF-TiN NFs) into a channel structure, to realize flow-through microfluidic electrochemical sensors for detecting nitrate ions in agricultural soils. The unique GF-TiN nanocomposite provides high electrochemical reactivity, high electron transfer rate, improved loading capacity of receptor biomolecules, and large surface area, serving as an efficient electrochemical sensing interface with the help of immobilized specific enzyme molecules. The microfluidic sensor provides an ultralow limit of detection of 0.01 mg L, a wide dynamic range from 0.01 to 442 mg L, and a high sensitivity of 683.3 μA mg L cm for nitrate ions in real soil solution samples. The advantageous features of the GF-TiN nanocomposite, in conjunction with the in situ integration approach, will enable a promising microfluidic sensor platform to monitor soil ions for nutrient management towards sustainable agriculture.

Miniature microbial fuel cell (MFC) technology has received growing interest due to its potential applications in high-throughput screening of bacteria and mutants to elucidate mechanisms of electricity generation. This paper reports a novel miniature MFC with an improved output power density and short startup time, utilizing electrospun conducting poly(3,4-ethylenedioxythiophene) (PEDOT) nanofibers as a 3D porous anode within a 12 μl anolyte chamber. This device results in 423 μW cm−3 power density based on the volume of the anolyte chamber, using Shewanella oneidensis MR-1 as a model biocatalyst without any optimization of bacterial culture. The device also excels in a startup time of only 1hr. The high conductivity of the electrospun nanofibers makes them suitable for efficient electron transfer. The mean pore size of the conducting nanofibers is several micrometers, which is favorable for bacterial penetration and colonization of surfaces of the nanofibers. We demonstrate that S. oneidensis can fully colonize the interior region of this nanofibers-based porous anode. This work represents a new attempt to explore the use of electrospun PEDOT nanofibers as a 3D anode material for MFCs. The presented miniature MFC potentially will provide a high-sensitivity, high-throughput tool to screen suitable bacterial species and mutant strains for use in large-size MFCs.

Reconfigurable metamaterials have great potential to alleviate complications involved in using passive metamaterials to realize emerging electromagnetic functions, such as dynamical filtering, sensing, and cloaking. This paper presents a new type of tunable meta-atoms in the X-band frequency range (8-12 GHz) toward reconfigurable metamaterials. The meta-atom is made of all flexible materials compliant to the surface of an interaction object. It uses a liquid metal-based split-ring resonator as its core constituent embedded in a highly flexible elastomer. We demonstrate that simple mechanical stretching of the meta-atom can lead to the great flexibility in reconfiguring its resonance frequency continuously over more than 70% of the X-band frequency range. The presented meta-atom technique provides a simple approach to dynamically tune response characteristics of metamaterials over a broad frequency range. V

Three-dimensional (3D) printing provides a new approach of fabricating implantable products because it permits a flexible manner to extrude complex and customized shapes of the tissue scaffolds. Compared with other printable biomaterials, the polyurethane elastomer has several merits, including excellent mechanical properties and good biocompatibility. However, some intrinsic behavior, especially its high melting point and slow rate of degradation, hampered its application in 3D printed tissue engineering. Herein, we developed a 3D printable amino acid modified biodegradable waterborne polyurethane (WBPU) using a water-based green chemistry process. The flexibility of this material endows better compliance with tissue during implantation and prevents high modulus transplants from scratching surrounding tissues. The histocompatibility experiments show that the WBPU induces no apparent acute rejection or inflammation in vivo. We successfully fabricated a highly flexible WBPU scaffold by deposition 3D printing technology at a low temperature (50°C ~ 70 °C), and the printed products could support the adhesion and proliferation of chondrocytes and fibroblasts. The printed blocks possessed controllable degradability due to the different amounts of hydrophilic chain extender and did not cause accumulation of acidic products. In addition, we demonstrated that our WBPU is highly applicable for implantable tissue engineering because there is no cytotoxicity during its degradation. Taken together, we envision that this printable WBPU can be used as an alternative biomaterial for tissue engineering with low temperature printing, biodegradability, and compatibility.