Digital polymerase chain reaction (dPCR) has found widespread applications in molecular diagnosis of various diseases owing to its sensitive single-molecule detection capability. However, the existing dPCR platforms rely on the auxiliary procedure to disperse DNA samples, which needs complicated operation, expensive apparatus, and consumables. Besides, the complex and costly dPCR readers also impede the applications of dPCR for point-of-care testing (POCT). Herein, we developed a portable digital loop-mediated isothermal amplification (dLAMP) platform, integrating a microscale hydrogel (microgel) array chip for sample partition, a miniaturized heater for DNA amplification, and a hand-held reader for digital readout. In the platform, the chip with thousands of isolated microgels holds the capability of self-absorption and partition of DNA samples, thus avoiding auxiliary equipment and professional personnel operations. Using the integrated dLAMP platform, λDNA templates have been quantified with a good linear detection range of 2−1000 copies/μL and a detection limit of 1 copy/μL. As a demonstration, the epidermal growth factor receptor L858R gene mutation, a crucial factor for the susceptibility of the tyrosine kinase inhibitor in nonsmall-cell lung cancer treatment, has been accurately identified by the dLAMP platform with a spiked plasma sample. This work shows that the developed dLAMP platform provides a low-cost, facile, and user-friendly solution for the absolute quantification of DNA, showing great potential for the POCT of nucleic acids.

Fast nucleic acid (NA) amplification has found widespread biomedical applications, where high thermocycling rate is the key. The plasmon‐driven nano‐localized thermocycling around the gold nanorods (AuNRs) is a promising alternative, as the significantly reduced reaction volume enables a rapid temperature response. However, quantifying and adjusting the nano‐localized temperature field remains challenging for now. Herein, a simple method is developed to quantify and adjust the nano‐localized temperature field around AuNRs by combining experimental measurement and numerical simulation. An indirect method to measure the surface temperature of AuNRs is first developed by utilizing the temperature‐dependent stability of Authiol bond. Meanwhile, the relationship of AuNRs′ surface temperature with the AuNRs concentration and laser intensity, is also studied. In combination with thermal diffusion simulation, the nano‐localized temperature field under the laser irradiation is obtained. The results show that the restricted reaction volume (≈aL level) enables ultrafast thermocycling rate (>104 °C s−1). At last, a duplex‐specific nuclease (DSN)‐mediated isothermal amplification is successfully demonstrated within the nano‐localized temperature field. It is envisioned that the developed method for quantifying and adjusting the nano‐localized temperature field around AuNRs is adaptive for various noble metal nanostructures and will facilitate the development of the biochemical reaction in the nano‐localized environment.

Electric field-induced micro-/nanopatterns in thin polymer films, sometimes referred as electrohydrodynamic patterning, is a promising technique to fabricate micro-/nanostructures. Extensive attention has been attracted because of its advantages in microcontact (easy demolding) and low cost. Although considerable work has been done on this technique, including both experimental and theoretical ones, there still appears a requirement for understanding the mechanism of electrohydrodynamic patterning. Thus, we systematically studied the effect of different parameters on electrohydrodynamic patterning with a numerical phase field model. Previous researchers usually employed lubrication approximation (i.e., long-wave approximation) to simplify the numerical model. However, this approximation would lose its validity if the structure height is on the same scale or larger than the wavelength, which occurs in most cases. Thus, we abandoned the lubrication approximation and solved the full governing equations for fluid flow and electric field. In this model, the deformation of polymer film is described by the phase field model. As to the electric field, the leaky dielectric model is adopted in which both electrical permittivity and conductivity are considered. The fluid flow together with electric field is coupled together in the framework of phase field. By this model, the effect of physical parameters, such as external voltage, template structure height, and polymer conductivity, is studied in detail. After that, the governing equations are nondimesionalized to analyze the relationship between different parameters. A dimensionless parameter, electrical Reynolds number E, is defined, for which, a large value would simplify the electric field to perfect dielectric model and a small value leads it to steady leaky model. These findings and results may enhance our understanding of electrohydrodynamic patterning and may be a meaningful guide for experiments.

It is crucial for the protection and sustainable development of villages in China to effectively determine the changes that have occurred in traditional villages’ architectural features and the causes of such changes in order to provide timely feedback, correct protection planning, and construction in these villages. This paper analyzed quantitative indexes at three different scales in Lingquan village, namely construction land, public infrastructure, and the form, material, and color of roofs, using remote sensing images at different time points, drone shooting, and a field survey. It was found that the rate of change of the architectural features at the village and street levels were low, with an overall trend of improvement observed. However, the residential roof features at the building level showed more changes, with a trend of deterioration observed. It was also found that the active participation of the government was the main reason for the substantial improvement observed in the village’s street-level features. Further, for residential houses, the lack of standard guidance for their protection and renovation, as well as the lack of protection awareness and participation mechanisms, were the main reasons found for the deterioration of the village’s building-level features. Finally, the study forwarded some suggestions in order to provide reference value for the timely revision of protection strategies for many villages in China similar to Lingquan village.

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