Contactless acoustic tweezer for droplet manipulation on superhydrophobic surfaces.

Droplet manipulation on superhydrophobic surfaces (DMSS) without conventional pipetting is an emerging liquid handling technology, which can be potentially used for diagnostic, analysis, and synthetic processes. Despite notable progress, controlling droplet motion on superhydrophobic surfaces by contactless acoustic waves is rarely reported. Herein, we report a contactless acoustic tweezer (CAT) for DMSS based on establishing ultrasonic standing wave between an ultrasound transducer (UST) and a superhydrophobic substrate to manipulate droplets without physical contact. The CAT utilizes acoustic radiation forces to trap and move droplets on superhydrophobic surfaces, which allows for precise and controllable movement of droplets by controlling the movement of the UST. Small droplets with volume less than 20 µL can be levitated in mid-air for out-plane manipulation, and large droplets with volume up to 500 µL can be trapped for in-plane manipulation. Experimental results demonstrate the versatility of the CAT for manipulating droplets with various compositions and volumes on various superhydrophobic substrates, offering a versatile and cross-contamination-free liquid handling approach for applications, including but not limited to high-throughput surface-enhanced Raman scattering.

Transmembrane capability of DNA origami sheet enhanced by 3D configurational changes.

DNA origami-engineered nanostructures are widely used in biomedical applications involving transmembrane delivery. Here, we propose a method to enhance the transmembrane capability of DNA origami sheets by changing their configuration from two-dimensional to three-dimensional. Three DNA nanostructures are designed and constructed, including the two-dimensional rectangular DNA origami sheet, the DNA tube, and the DNA tetrahedron. The latter two are the variants of the DNA origami sheet with three-dimensional morphologies achieved through one-step folding and multi-step parallel folding separately. The design feasibility and structural stability of three DNA nanostructures are confirmed by molecular dynamics simulations. The fluorescence signals of the brain tumor models demonstrate that the tubular and the tetrahedral configurational changes could dramatically increase the penetration efficiency of the original DNA origami sheet by about three and five times, respectively. Our findings provide constructive insights for further rational designs of DNA nanostructures for transmembrane delivery.

Advanced tools and methods for single-cell surgery.

Highly precise micromanipulation tools that can manipulate and interrogate cell organelles and components must be developed to support the rapid development of new cell-based medical therapies, thereby facilitating in-depth understanding of cell dynamics, cell component functions, and disease mechanisms. This paper presents a literature review on micro/nanomanipulation tools and their control methods for single-cell surgery. Micromanipulation methods specifically based on laser, microneedle, and untethered micro/nanotools are presented in detail. The limitations of these techniques are also discussed. The biological significance and clinical applications of single-cell surgery are also addressed in this paper.

Automated Optical Tweezers Manipulation to Transfer Mitochondria from Fetal to Adult MSCs to Improve Antiaging Gene Expressions.

Mitochondrial dysfunction is considered to be an important factor that leads to aging and premature aging diseases. Transferring mitochondria to cells is an emerging and promising technique for the therapy of mitochondrial deoxyribonucleic acid (mtDNA)-related diseases. This paper presents a unique method of controlling the quality and quantity of mitochondria transferred to single cells using an automated optical tweezer-based micromanipulation system. The proposed method can automatically, accurately, and efficiently collect and transport healthy mitochondria to cells, and the recipient cells then take up the mitochondria through endocytosis. The results of the study reveal the possibility of using mitochondria from fetal mesenchymal stem cells (fMSCs) as a potential source to reverse the aging-related phenotype and improve metabolic activities in adult mesenchymal stem cells (aMSCs). The results of the quantitative polymerase chain reaction analysis show that the transfer of isolated mitochondria from fMSCs to a single aMSC can significantly increase the antiaging and metabolic gene expression in the aMSC. The proposed mitochondrial transfer method can greatly promote precision medicine for cell therapy of mtDNA-related diseases.

Experimental and early investigational drugs for androgenetic alopecia.

INTRODUCTION: Treatments for androgenetic alopecia constitute a multi-billion-dollar industry, however, currently available therapeutic options have variable efficacy. Consequently, in recent years small biotechnology companies and academic research laboratories have begun to investigate new or improved treatment methods. Research and development approaches include improved formulations and modes of application for current drugs, new drug development, development of cell-based treatments, and medical devices for modulation of hair growth. Areas covered: Here we review the essential pathways of androgenetic alopecia pathogenesis and collate the current and emerging therapeutic strategies using journal publications databases and clinical trials databases to gather information about active research on new treatments. Expert opinion: We propose that topically applied medications, or intra-dermal injected or implanted materials, are preferable treatment modalities, minimizing side effect risks as compared to systemically applied treatments. Evidence in support of new treatments is limited. However, we suggest therapeutics which reverse the androgen-driven inhibition of hair follicle signaling pathways, such as prostaglandin analogs and antagonists, platelet-rich plasma (PRP), promotion of skin angiogenesis and perfusion, introduction of progenitor cells for hair regeneration, and more effective ways of transplanting hair, are the likely near future direction of androgenetic alopecia treatment development.