Journal of Laboratory Automation

Semiconductor quantum dots (Qdots) have emerged as novel ultrasensitive optical probes to target, detect, and image fundamental events occurring within the biological system. In particular, near-infrared (near-IR) Qdots holds great promise as in vivo contrast agents for real-time bioimaging capabilities. In this study, biocompatible near-IR Qdots are used to image organs, tissues, and cells. Compared to visible Qdots, we obtained a significant enhancement in signal detection sensitivity for imaging deep tissues and organs. In addition, biomolecules were used to target these optical contrast agents for multiplexed imaging of cells and organs in vivo. The ability to simultaneously distinguish emission profiles of multiple near-IR Qdots will likely emerge as important tools for addressing fundamental questions in molecular biology and in medical sciences.

A fully automated robotic system was developed and deployed in-house in a modular way to meet the needs of a high throughput chemistry laboratory. The main system components consist of a Stäubli TX60 industrial robot and a Vapourtec V-10 evaporator, with control software by Aitken Scientific. A custom server application was written by Stäubli robotics to interface the robot and control software. The design was done using SolidWorks Computer Aided Design to speed up development, with out-sourced software development and hardware procurement or fabrication. Both hardware and software were modularized such that components could be reused in the future. An industrial robot and original equipment manufacturer (OEM) components were used to improve reliability and minimize support. A custom gripper was designed using a Schunk MPG50 pneumatic two-finger parallel actuator with stainless steel fingers. An injector station was designed to simplify and automate large volume evaporations, with built-in self-cleaning. Custom fabrication of racks, grippers, etc was done using local precision engineering firms. Providing full documentation and training allows support to be done by third-party service engineers. Initial data show that the system is both intuitive and reliable in use.

There are several advantages to using liquid-filled automated liquid-handling systems equipped with reusable fixed tips for sample handling of bioanalytical assays. However, liquid-handling parameters that have not been optimized can lead to sample dilution by the system liquid of the automated liquid handler causing possible inaccuracy of sample delivery. In this investigation, liquid-handling parameters involving sample delivery, such as aspiration speed, dispense speed, partition volume, excess volume, and air gaps, were closely examined to understand their roles in the accurate delivery of the sample. Consequently, two strategies for optimization of the parameters are presented that achieve accurate sample delivery while maintaining sample integrity.

A technology for electrical detection of protein biomarkers has been developed. It is based on developing high-density, low-volume multiwell plate devices. The scientific core of this technology lies in integrating nanoporous membranes with microfabricated chip platforms. This results in the conversion of individual pores into wells of picoliter volume. Specific antibodies are localized and isolated into individual wells. The formation of the antibody–antigen-binding complex occurs in individual wells. The membrane allows for robust separation among individual wells.

This technology has the capability to achieve near real-time detection with improved sensitivity and selectivity. This is due to the two factors associated with the technology: (1) event-based electrochemical detection process, where the individual step in the formation of the binding complex results in a specific change to the electrochemical conductance due to the pertubation of the electrical double layer at the base of the each well. (2) The nanoporous membrane is an electrical insulator and is structurally robust throughout hence there is improved signal-to-noise ratio and cross-contamination between is minimized.

Another advantage of this technique is the use of electrical signal in protein identification as compared to the use of optical methods; hence, it is a noninvasive and a label-free technique. The signal acquisition is simple and it uses the existing data acquisition and signal analysis methods.

We have demonstrated the use of this technology for addressing a specific clinical problem: identification of vulnerable coronary plaque in the perioperative state.

Forensic crime scene sample analysis, by its nature, often deals with samples in which there are low amounts of nucleic acids, on substrates that often lead to inhibition of subsequent enzymatic reactions such as PCR amplification for Short Tandem Repeat (STR) profiling. Common substrates include denim from blue jeans, which yields indigo dye as a PCR inhibitor, and soil, which yields humic substances as inhibitors. These inhibitors frequently co-extract with nucleic acids in standard column or bead-based preps, leading to frequent failure of STR profiling. We present a novel instrument for DNA purification of forensic samples that is capable of highly effective concentration of nucleic acids from soil particulates, fabric, and other complex samples including solid components. The novel concentration process, known as Synchronous Coefficient of Drag Alteration, is inherently selective for long-charged polymers such as DNA, and therefore is able to effectively reject known contaminants. We present an automated sample preparation instrument based on this process, and preliminary results based on mock forensic samples.

Here, we present an approach to design, fabricate, and create a simple, low-cost, and rapid prototyping crossbar junction using a p-type and n-type multiwalled carbon nanotubes (MWCNTs) via microcontact printing. This is achieved using poly-dimethylsiloxane (PDMS) molds. The parallel relief structure in order of a few micrometers is used to transfer continuous horizontal arrays of these MWCNTs in aqueous suspension. Using an alignment and the stamping process, PDMS molds are inked alternatively with p-type and n-type MWCNTs suspensions and transferred in a grid-like manner onto the base microelectrode platform. Parallel alignment of these MWCNTs is achieved due to the geometry of the mold relief structures. The hierarchical assembly results in the formation of the crossbar array structures. The functionality of this circuit has been demonstrated through the current–voltage (I–V) characteristics associated with the junction formation.