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Among the vast number of recognition molecules, DNA aptamers generated from cell-SELEX exhibit unique properties for identifying cell membrane biomarkers, in particular protein receptors on cancer cells. To integrate all recognition and computing modules within a single structure, a three-dimensional (3D) DNA-based logic gate nanomachine was constructed to target overexpressed cancer cell biomarkers with bispecific recognition. Thus, when the Boolean operator "AND" returns a true value, it is followed by an "ON" signal when the specific cell type is presented. Compared with freely dispersed double-stranded DNA (dsDNA)-based molecular circuits, this 3D DNA nanostructure, termed DNA-logic gate triangular prism (TP), showed better identification performance, enabling, in turn, better molecular targeting and fabrication of recognition nanorobotics.

We have investigated the capability of single-walled carbon nanotubes (SWNTs) to penetrate the cell wall and cell membrane of intact plant cells. Confocal fluorescence images revealed the cellular uptake of both SWNT/fluorescein isothiocyanate and SWNT/DNA conjugates, demonstrating that SWNTs also hold great promise as nanotransporters for walled plant cells. Moreover, the result suggested that SWNTs could deliver different cargoes into different plant cell organelles.

Conjugation of the cell-penetrating peptide derived from the human immunodeficiency virus-1 transactivator protein (TAT) to semiconductor quantum dots (QDs) is an effective way to enhance transmembrane delivery of QDs for intracellular and molecular imaging. In this work, the internalization pathway of TAT-QDs was studied systematically in living cells. Cellular uptake of TAT-QDs, under different endocytosis-inhibiting conditions, was compared by fluorescence imaging and flow cytometry. The results suggest TAT-QDs internalize through lipid-raft-dependent macropinocytosis, which is different from that of FITC-labeled TAT. They also provide new information for better understanding of the TAT-mediated cell uptake mechanism.

Bioconjugation based on crosslinking primary amines to carboxylic acid groups has found broad applications in protein modification, drug development, and nanomaterial functionalization. However, proteins, which are made up of amino acids, typically give nonselective bioconjugation when using primary amine-based crosslinking. In order to control protein orientation and activity after conjugation, selective bioconjugation is desirable. We herein report an efficient and cysteine-selective thiol-ene click reaction-based bioconjugation strategy using colloidal nanoparticles. The resulting thiol-ene based aptamer and enzyme nanoconjugates demonstrated excellent target binding ability and enzymatic activity, respectively. Thus, thiol-ene click chemistry can provide a stable and robust crosslinker in a biocompatible manner for bioconjugation of any thiol-containing biomolecule with nanomaterials. This will open more opportunities for applications of thiol-ene reactions and functional colloidal nanoparticles in chemical biology.

Due to its excellent programmability and biocompatibility, DNA molecule has unique advantages in cell surface engineering. Recent progresses provide a reliable and feasible way to engineer cell surfaces with diverse DNA molecules and DNA nanostructures. The abundant form of DNA nanostructures has greatly expanded the toolbox of DNA‐based cell surface engineering and gave rise to a variety of novel and fascinating applications. In this review, we summarize recent advances in DNA‐based cell surface engineering and its biological applications. We first introduce some widely used methods of immobilizing DNA molecules on cell surfaces and their application features. Then we discuss the approaches of employing DNA nanostructures and dynamic DNA nanotechnology as elements for creating functional cell surfaces. Finally, we review the extensive biological applications of DNA‐based cell surface engineering and discuss the challenges and prospects of DNA‐based cell surface engineering. [ABSTRACT FROM AUTHOR]

Keywords: nanotechnology; cell surface engineering; DNA nanostructure; cell recognition; cell manipulation EN nanotechnology cell surface engineering DNA nanostructure cell recognition cell manipulation 1 1 1 12/13/22 20221209 NES 221209 DNA-based cell surface engineering is a powerful tool for manipulating cell surface and cell behavior. Nanotechnology, cell surface engineering, DNA nanostructure, cell recognition, cell manipulation We believe that DNA-based cell surface engineering will be capable of bringing more opportunities to cell surface engineering and cell-based biomedical applications. [Extracted from the article]

In the past two decades, the study of cancer therapy has gradually advanced to the 'nano' era. Numerous novel nanomaterials armed with unique physical properties have been introduced into biomedical research. At the same time, functional nucleic acid molecules, especially aptamers, have aroused broad attention from the biomedical community. Benefiting from the advancement of molecular engineering strategies, it is now feasible to combine the cancer-specific recognition capability of aptamers with various other special functions of nanomaterials to develop cancer-specific drugs at the nanoscale. Nanodrugs are now offering an unprecedented opportunity to achieve the goal of efficient targeted delivery as well as controlled release. This review highlights some achievements made in multiple aptamer-based nanodrug systems that have emerged in recent years, including studies in the infant stage of 'proof-of-concept'. [ABSTRACT FROM AUTHOR]

With the rapid development of nanotechnology, nanoparticles with various sizes and compositions have been synthesized and proposed for industrial applications. At the same time, the health effects and environmental impacts of nanoparticles become an emerging concern to be addressed. Both in vitro and in vivo studies are of importance to better understand the toxicity of nanoparticles. It is thus essential to have a nanoparticle disperser capable of dispersing individual nanoparticles for these studies. A twin-head electrospray (THES) nanoparticle disperser for animal inhalation exposure studies has recently become commercially available from TSE Systems Inc. Different from the cone-jet electrospray method used in the majority of literature, this particular disperser operates at the multi-jet mode. In this study, we reported our finding on the performance evaluation of the THES disperser with respect to its mass throughput and quality of size distribution of aerosol produced. Three different nanomaterials (TiO, ZnO, and NiO) were used in this study. It is found that the maximal mass throughput of the studied disperser was achieved by keeping the distance between two opposite spray capillary tips at 3.0 cm, operating the primary carrier-to-capillary sheath flow rates at the ratio of 4:3, and feeding spray suspensions at a flow rate of 20 µl/min. Under the above settings and operations, the highest mass concentration for nano-ZnO was measured at 14.56 mg/m. Nanoparticle streams with higher concentrations can be further produced by lowering the total carrier gas flow rate and spraying suspensions of higher nanomaterial concentrations. Our study also found that the particle mass throughput of the studied disperser had a good linear relationship with the mass concentration of spray suspension. In addition, the spatial uniformity of nano aerosol distribution in a TSE head-nose-only exposure chamber was investigated. An acceptable nano aerosol uniformity result was concluded based on the criteria of the coefficient of variation. Highlights: [ABSTRACT FROM AUTHOR]

DNA molecular machines show great promise in fields such as biomarker discovery and biological activity regulation, but operating DNA machines with specific functions within living systems remains extremely challenging. Although DNA machines have been engineered with exact molecular-level specifications, some intrinsic imperfections such as poor cell permeation and fragility in complex cytoplasmic milieu persist due to the well-established character of nucleic acid molecules. To circumvent these problems, we herein report a molecularly engineered, entropy-driven three-dimensional DNA amplifier (EDTD) that can operate inside living cells in response to a specific mRNA target. In particular, mRNA target/ EDTD interaction can specifically initiate an autonomous DNA circuit inside living cells owing to the exclusive entropy-driven force, thus providing enormous signal amplification for ultrasensitive detection of the mRNA. Moreover, owing to molecular engineering of a unique DNA tetrahedral framework into the DNA amplifier, EDTD exhibits significantly enhanced biostability and cellular uptake efficiency, which are prerequisites for DNA machines used for in vivo applications. This programmable DNA machine presents a simple and modular amplification mechanism for the detection of intracellular biomarkers. Moreover, this study provides a potentially valuable molecular tool for understanding the chemistry of cellular systems and offers a design blueprint for further expansion of DNA nanotechnology in living systems. [ABSTRACT FROM AUTHOR]