Engineering personalized neural tissue using functionalized transcription factors

Diseases and disorders of the central nervous system often require significant interventions to restore lost function due to their com- plexity. Examples of such disorders include Parkinson＇s disease, Alzheimer＇s disease, multiple sclerosis, traumatic brain injury, and spinal cord in）ury. These diseases and disorders result trom healthy cells being destroyed, which in turn causes dysfunction in the cen- tral nervous system, The death of these cells can trigger a cascade of events that affect the rest of the body, causing symptoms that become progressively worse over time. Developing strategies for repairing the damage to the central nervous system remains chal- lenging, in part due to its inability to regenerate.

Work function engineering to enhance open-circuit voltage in planar perovskite solar cells by g-C_(3)N_(4) nanosheets

Enhancement of open-circuit voltage(Voc)is an effective way to improve power conversion efficiency(PCE)of the perovskite solar cells(PSCs).Theoretically,work function engineering of TiO2 electron transport layer can reduce both the loss of Voc and current hysteresis in PSCs.In this work,two-dimensional g-C_(3)N_(4) nanosheets were adopted to modify the compact TiO2 layers in planar PSCs,which can finely tune the work function(WF)and further improve the energy level alignment at the interface to enhance the Voc and diminish the hysteresis.Meanwhile,the quality of perovskite films and charge transfer of the devices were improved by g-C_(3)N_(4) nanosheets.Therefore,the PCE of the planar PSCs was champed to 19.55%without obvious hysteresis compared with the initial 15.81%,mainly owing to the remarkable improvement of VOC from 1.01 to 1.11 V.In addition,the stability of the devices was obviously improved.The results demonstrate an effective strategy of W_(F) engineering to enhance Voc and diminish hysteresis phenomenon for improving the performance of PSCs.

Resolution and contrast enhancements of optical microscope based on point spread function engineering

Point spread function （PSF） engineering-based methods to enhance resolution and contrast of optical microscopes have experienced great achievements in the last decades. These techniques include： stimulated emis- sion depletion （STED）, time-gated STED （g-STED）, ground-state depletion microscopy （GSD）, difference confocal microscopy, fluorescence emission difference microscopy （FED）, switching laser mode （SLAM）, virtual adaptable aperture system （VAAS）, etc. Each affords unique strengths in resolution, contrast, speed and expenses. We explored how PSF engineering generally could be used to break the diffraction limitation, and concluded that the common target of PSF engineering- based methods is to get a sharper PSF. According to their common or distinctive principles to reshape the PSF, we divided all these methods into three categories, nonlinear PSF engineering, linear PSF engineering, and linear-based nonlinear PSF engineering and expounded these methods in classification. Nonlinear effect and linear subtraction is the core techniques described in this paper from the perspective of PSF reconstruction. By comparison, we emphasized each method＇s strengths, weaknesses and biologic applications. In the end, we promote an expecta- tion of prospective developing trend for PSF engineering.

Functional engineering strategies of 3D printed implants for hard tissue replacement

Three-dimensional printing technology with the rapid development of printing materials are widely recognized as a promising way to fabricate bioartificial bone tissues.In consideration of the disadvantages of bone substitutes,including poor mechanical properties,lack of vascularization and insufficient osteointegration,functional modification strategies can provide multiple functions and desired characteristics of printing materials,enhance their physicochemical and biological properties in bone tissue engineering.Thus,this review focuses on the advances of functional engineering strategies for 3D printed biomaterials in hard tissue replacement.It is structured as introducing 3D printing technologies,properties of printing materials(metals,ceramics and polymers)and typical functional engineering strategies utilized in the application of bone,cartilage and joint regeneration.

Dielectric metasurfaces for distance measurements and three-dimensional imaging

Ultrathin metasurfaces have shown the capability to influence all aspects of light propagation.This has made them promising options for replacing conventional bulky imaging optics while adding advantageous optical properties or functionalities.We demonstrate that such metasurfaces can also be applied for single-lens three-dimensional(3-D)imaging based on a specifically engineered point-spread function(PSF).Using Huygens’metasurfaces with high transmission,we design and realize a phase mask that implements a rotating PSF for 3-D imaging.We experimentally characterize the properties of the realized double-helix PSF,finding that it can uniquely encode object distances within a wide range.Furthermore,we experimentally demonstrate wide-field depth retrieval within a 3-D scene,showing the suitability of metasurfaces to realize optics for 3-D imaging,using just a single camera and lens system.