Synthesis of Branched DNA Scaffolded Super‐Nanoclusters with Enhanced Antibacterial Performance

Metal nanoclusters (NCs) possess unique optical properties, and exhibit a wide variety of potential applications. DNA with robust molecular programmability is demonstrated as an ideal scaffold to regulate the formation of NCs, offering a rational approach to precisely tune the spatial structures of NCs. Herein, the first use of branched DNA as scaffold to regulate the formation of silver nanoclusters (super‐AgNC) is reported, in which the spatial structures are precisely designed and constructed. Super‐AgNC with tunable shapes and arm‐lengths including Y‐, X‐, and (Y–X)‐ shaped super‐AgNC is achieved. The molecular structures and optical properties of super‐AgNCs are systemically studied. As a proof of application, remarkably, super‐AgNCs exhibit superior antibacterial performance. In addition, super‐AgNCs show excellent biocompatibility with three types of tissue cells including 293T (human embryonic kidney cells), SMCs (vascular smooth muscle cells), and GLC‐82 (lung adenocarcinoma cells). These performances enable the super‐AgNCs adaptable in a variety of applications such as biosensing, bioimaging, and antibacterial agents.     

Structural Studies of DNA–Cationic Lipid Complexes Confined in Lithographically Patterned Microchannel Arrays

We have used lithographically patterned microchannel arrays with channel widths ranging from 1 to 20 m, fabricated using electron beam lithography and reactive ion etching, in structural studies of DNA–cationic lipid complexes in confinement. Various techniques have been developed for loading these DNA–membrane complexes into the microchannels or to form the complexes in situ by sequentially depositing DNA and lipid solutions into the microchannels. Optical microscopy studies indicate that such complex formation is strongly influenced by the periodic channel structure even at channel widths much larger than the persistent length of the DNA molecules. Preliminary x-ray diffraction experiments conducted at Stanford Synchrotron Radiation Laboratory (SSRL) yielded only a weak signal from the lipid bilayers in the complexes. The use of a microfocused x-ray beam produced by the newly developed Bragg–Fresnel optics at a third-generation synchrotron facility may dramatically increase the signal-to-noise ratio and allow observation of orientational as well as positional ordering of DNA molecules induced by the microchannels. Structural control of the DNA–membrane complexes has a broad range of potential applications in gene probe technology and as mesoscopic biomolecular composites.     

基于PDF417条码的信息隐藏算法

针对现有隐藏方法存在嵌入信息量少、鲁棒性差、安全性低的不足,提出一种改进的基于PDF417条码的信息隐藏算法。该算法对隐藏信息进行扩频和映射处理,根据PDF417条码自身结构特点,通过微调条码中的条和空将信息隐藏其中。实验结果表明,该算法隐藏的信息在经受打印扫描和污损攻击后,仍具有较高提取率。     

基于LPC2138的超市收银机系统设计

给出一种基于Philips公司的ARM7 LPC2138微控制器的超市收银管理系统的设计方法。该系统不仅实现商品价目表（PLU）,销售日志保存、记录和打印,中英文字符和数字输入等基本功能,还实现了对超市环境参数监测报警、语音播报及语音识别等功能。     

The effect of DNA probe distribution on the reliability of label-free biosensors

As the design of label-free DNA biosensors matures, and their sizes reduced to enhance their sensitivity, not much has been researched about the variations in the received signal with the positioning of the probes on the sensitive surface. We approach this issue computationally in this paper. By adopting the finite-element model on a three-dimensional biological field-effect transistor (BioFET) slice, and running Monte-Carlo simulations on the positions of the DNA molecules, we extract the expected variations in the signal. Then, we show that signal-to-noise (SNR) ratio can be low enough to hinder the functionality of the device, placing a limitation on how low the sensitivity of a sensor of a certain size can be.     

基于DNA下推自动机二进制减法和乘法的实现

提出了基于DNA下推自动机二进制减法和乘法的实现方法.一位二进制借位减法,是通过预先构造好的DNA下推自动机模型在一个试管中以该模型的运行方式自动完成运算.m位二进制借位减法,是在一位二进制减法的基础上,按照从低位到高位的顺序,将低位产生的借位作为高位试管操作巾的输入符号串,从而完成高位的减法运算.两位二进制乘法中包含移位和加法操作,在两个试管中分别设计好DNA下推自动机模型,分别完成被乘数与乘数各位的移位操作,同时结合相应的生物操作,将其作为另一个试管加法操作中的输入符号串,则加法操作中产牛的结果即为所求.在此基础上,m位二进制乘法可通过移位操作的并行性和加法操作的串行性来完成运算.这些实现方法为DNA下推自动机实现基本的算术运算提供了比较完整的运算机制.     

Application of a novel IWO to the design of encoding sequences for DNA computing

Encoding and processing information in DNA-, RNA- and other biomolecule-based devices is an important requirement for DNA based computing with potentially important applications. To make DNA computing more reliable, much work has focused on designing the good DNA sequences. However, this is a bothersome task as encoding problem is an NP problem. In this paper, a new methodology based on the IWO algorithm is developed to optimize encoding sequences. Firstly, the mathematics models of constrained objective optimization design for encoding problems based on the thermodynamic criteria are set up. Then, a modified IWO method is developed by defining the colonizing behavior of weeds to overcome the obstacles of the original IWO algorithm, which cannot be applied to discrete problems directly. The experimental results show that the proposed method is effective and convenient for the user to design and select effective DNA sequences in silicon for controllable DNA computing.     

A rapid polymerisation process realizing 3D biocompatible structures in a microfluidic channel suitable for genetic analysis

Surface probe immobilisation is a complex and time consuming task undertaken prior to microfluidic integration, this requires surface functionalisation, biomolecule spotting, incubation and blocking steps. Traditional bonding techniques (anodic, thermal, etc.) or adhesives (UV cured) used to seal fluidic systems may denature biomolecules due to high temperature or vapour effects, thus bonding techniques such as thin film laminate or PDMS are used to seal systems, with substrate-fluidic alignment required prior to bonding. We propose a technique allowing probe DNA molecules to be immobilised in a sealed microfluidic system using (3D) hydrogel structures without any alignment steps. A prepolymer solution is introduced to the channels where photo-polymerisation is undertaken forming 3D structures covalently attached to the channel surface. We use a photo-initiated prepolymer material poly-ethylene-glycol (PEG) to form structures containing probe DNA. This process is fast compared to conventional biomolecule immobilisation techniques and is also biocompatible, this direct write approach removes overnight immobilisation/incubation of the probe DNA, it also facilitates immobilisation within a sealed fluidic system where conventionally DNA probe spots must be immobilised prior to channel sealing. We consider the transport of target DNA from bulk analyte to the 3D gel structure and evaluate hybridisation within the microfluidic system.     

基于XML的DNA公共数据模型

针对目前DNA数据组织与处理中存在的数据异构问题,提出一个基于XML的DNA公共数据模型（DCDM）。该模型具有很强的可扩展性,能克服一般公共数据模型的作用范围小的缺点,可用于构建DNA研究领域统一的DNA数据描述模式。实验结果表明,该模型能解决DNA数据异构中的语义异构。