Current proteomics experiments often rely upon printing techniques such as ink jet, pin, or quill arrayers that were developed for the creation of cDNA microarrays. These techniques often do not meet the spotting requirements needed for successful high throughput protein identification and profiling. The Naval Research Laboratory has developed an alternative to these commercially available arrayers that does not rely upon a solid pin or capillary-based fluidics. This presentation describes experiments demonstrating that biological laser printing, or BioLP, is capable of depositing microarrays of proteins rapidly and efficiently. This technique utilizes a focused laser pulse to obtain micron-scale resolution rather than a pin or orifice, thereby eliminating clogging and protein loss commonly encountered in commercially available printers. The speed and spot-to-spot reproducibility of the printer is comparable to other techniques, while the minimum spot diameter and volume per printed droplet is significantly less at 30 microns and ~500 fL, respectively. The transfer of fluid by BioLP occurs through a fluid jetting mechanism, as observed by high-speed images of the printing process. In addition, printed biotinylated bovine serum albumin is identified through immunoassay and observed by fluorescent detection. These results indicate that BioLP holds promise as a novel protein printer for use in a wide range of applications in the proteomics field.
As laser micromachining is applied to ever smaller structures and more complex materials, the demand for greater control of the laser energy budget, in space and time, grows commensurately. Here we describe materials modification using picosecond resonant laser excitation in the mid-infrared spectral region to create spatially and temporally dense vibrational, rather than electronic, excitation. Examples include ablation of fused silica and machining of crystalline quartz; deposition of functionalized polymers on microstructures, and laser-directed transfer of proteins and nucleotides from a matrix of water ice. The experiments demonstrate that high spatial and temporal density of vibrational excitation can be achieved by ultrafast resonant infrared excitation of selected vibrational modes of these materials. In some cases, resonant infrared materials modification is far more successful than techniques based on ultraviolet excimer lasers. The laser used for most of the experiments was a tunable, high pulse-repetition frequency free-electron laser. However, a comparison of polymer deposition using a conventional nanosecond laser at a wavelength of 2.94 μm shows that the possibility exists for transferring the concept to conventional table-top devices. Mechanistic considerations nevertheless suggest that utlrashort pulses are likely to be more useful than longer pulses for many applications. A figure of merit is proposed for self-consistent comparisons of processing efficiency among different lasers.
KEYWORDS: Sensors, Chemical fiber sensors, Polymers, Silver, Temperature sensors, Fabrication, Biosensors, Chemical elements, Manufacturing, Electrodes
The use of direct-write techniques in the design and manufacture of sensor devices provides a flexible approach for next generation commercial and defense sensor applications. Using a laser forward transfer technique, we have demonstrated the ability to rapidly prototype temperature, biological and chemical sensor devices. This process, known as matrix assissted pulsed laser evaporation direct-write or MAPLE-DW is compatible with a broad class of materials ranging form metals and electronic ceramics to chemoselective polymers and biomaterials. Various types of miniature sensor designs have been fabricated incorporating different materials such as metals, polymers, biomaterials or composites as multilayers or discrete structures on a single substrate. The MAPLE-DW process is computer controlled which allows the sensor design to be easily modified and adapted to any specific application. To illustrate the potential of this technique, a functional chemical sensor system is demonstrated by fabricating all the passive and sensor components by MAPLE-DW on a polyimide substrate. Additional devices fabricated by MAPLE DW including biosensors and temperature sensors and their performance are shown to illustrate the breadth of MAPLE DW and how this technique may influence current and future sensor applications.
This paper outlines investigations into a potentially revolutionary approach to tissue engineering. Tissue is a complex 3D structure that contains many different biomaterials such as cells, proteins, and extracellular matrix molecules that are ordered in a very precise way to serve specific functions. In order to replicate such complex structure, it is necessary to have a tool that could deposit all these materials in an accurate and controlled fashion. Most methods to fabricate living 3D structures involve techniques to engineer biocompatible scaffolding, which is then seeded with living cells to form tissue. This scaffolding gives the tissue needed support, but the resulting tissue inherently has no microscopic cellular structure because cells are injected into the scaffolding where they adhere ta random. Wee have developed a novel technique that actually engineers tissue, not scaffolding, that includes the mesoscopic cellular structure inherent in natural tissues. This approach uses a laser-based rapid prototyping system known as matrix assisted pulsed laser evaporation direct write to construct living tissue cell-by- cell. This manuscript details our efforts to rapidly and reproducibly fabricate comlpex 2D and 3D tissue structures with MAPLE-DW by placing different cells and biomaterials accurately and adherently on the mesoscopic scale.
Conference Committee Involvement (1)
Laser Applications in Microelectronics and Optoelectronic Manufacturing VIII
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