CU-BioE: Biophotonics Lab

Lab Coordinator: Dr. Zhi Gao

Biophotonics Lab Members and Research Interests

Kirk Pirlo
Research Interests: I am interested in neuronal networks, laser guidance, and microfabrication techniques for the creation of biochips. Specifically I am interested in using laser guidance, an optical trapping technique, and microfluidic devices to create biochip models of neuronal networks for studying network processing dynamics and neurodegenerative disease.

My research focus is toward creating highly defined (geometrically, and directionally) in vitro neuronal networks using micro fabrication techniques, including soft lithography, step-wise photo-thermal etching, and our labs unique laser cell deposition system. The motivation for this is to create simplified models of neuronal circuits, which can then be studied using microscopic, electrophysiological (microelectrode array), and molecular analysis for several purposes; 1) To investigate the propagation of neurodegenerative disease between presynaptic and postsynaptic neurons, and create a biochip model for use in testing drugs and therapies. 2. Understand how neuronal network structure influences the learning and processing activity observed in random, higher density MEA coupled neuron cultures. We hypothesize that the ability to create highly defined neuronal networks will help bridge the gap between the wealth of knowledge on single neuron electrophysiology, and network phenomenon. A large part of my work thus far has been devoted to developing new hardware and software, and optimizing the optics for the laser cell deposition system. Briefly, this system exploits the same optical forces used in laser tweezers or optical trapping, but the laser is focused in such a way as to guide cells in the direction of the beams propagation while dimension while trapping them in the plane normal to the laser beam, this is termed laser guidance. Using the laser cell deposition system, we can visually inspect and select individual cells, and then deposit them with micron accuracy to a specific point on the substrate to create highly defined cell patterns. The application of this tool extends beyond my research focus and is used throughout the biophotonics lab to investigate the cell-cell interactions and spatial effects on cardiomyocytes, fibroblasts and stem cells.

www.russellkirkpirlo.com

Andrew Sweeney
Research Interests: Andrew is interested in applying microfluidics to miniaturize and automate cell-culture assays to elucidate single-cell interactions with the microenvironment for tissue-engineering studies as well as for bioinstrumentation and diagnostics. He is currently studying neurite outgrowth in response to soluble gradients of growth factors and drugs established by timed-release from biodegradable microspheres. Andrew has also begun studies on the effect of tumor and metastatic site microenvironment on immune cell-mediated immune surveillance and the immune privilege enjoyed by individual breast cancer cells.

Andrew Sweeney
Research Interests: Andrew is interested in apply microfluidics to miniaturize and automate cell-culture assays to elucidate single-cell interactions with the microenvironment for tissue-engineering studies as well as for bioinstrumentation and diagnostics. He is currently studying neurite outgrowth in response to soluble gradients of growth factors and drugs established by timed-release from biodegradable microspheres. Andrew has also begun studies on the effect of tumor and metastatic site microenvironment on immune cell-mediated immune surveillance and the immune privilege enjoyed by individual breast cancer cells.

Keywords: microfluidics, laser cell micropatterning, cell motility,breast cancer metastasis and immune privilege, neurite outgrowth,biodegradable polymers for drug delivery and tissue engineering, soluble factors

Drew McRae
Research Interests: My research deals with mapping the traction force fields generated by cells. As cells migrate or contract, they exert forces on the surfaces they are in contact with. These forces play an integral role in communication and regulation of cell function; however, quantification of such fields can be problematic. Many techniques have been developed that utilize high-resolution imagery and the finite element method to generate mathematical stress models by comparing images in a series. To take the next step, we plan to develop our own technique that can generate stress models from a video source instead of two static images. In doing so, we aspire to aid the study of macro-cellular biomechanics by extending analysis into the time domain.

Justin Roman
Research Interests:
1. Optics-Based Cell Sorting and Disease Diagnostics
There exists a need for a technique that can analyze and/or sort a sample of cells without requiring highly specific cellular markers.
2. Design of a Portable Laser Guidance Microscope
Current in vitro cell culture models lack the precise control of an in vivo-like cell orientation. Laser guidance, a modification to optical tweezers, has shown great potential for creating specific patterns of cells on a substrate.

Justin Roman
Research Interests:
1. Optics-Based Cell Sorting and Disease Diagnostics

There exists a need for a technique that can analyze and/or sort a sample of cells without the requirement of highly specific cellular markers. Starting from the gene mutation, the development of cancer is accompanied with phenotypical changes at the cellular level including the following: overall size, shape, internal structure, and surface membrane properties. Using the force created by a weakly focused laser beam, a phenotypically altered cell can be distinguished from its unaltered form. A change in size or shape results in different effective scattering cross-sections for the beam to interact with, and as a consequence, distinct differences in optical force. Also, changes in the internal structure or surface membrane composition lead to changes in refractive index and, again, changes in the magnitude of force acting on the cell. Therefore, even the most subtle of cellular phenotype changes are distinguishable by evaluating the optical force generated by its interaction with a focused laser source. By simply measuring the traveling velocities of a cell resulting from these optical forces, it is possible to distinguish phenotypically different cell types, ultimately exemplifying a novel and unique method of diagnosing cancer without the need for individual biological markers.

2. Design of a Portable Laser Guidance Microscope
Current in vitro cell culture models lack the precise control of an in vivo-like cell orientation. Laser guidance, a modification to optical tweezers, has shown great potential for creating specific patterns of cells on a substrate. Based on this, we have developed a portable laser guidance microscope. The major components of this system include an on-stage incubated chamber within which an 808nm, 200mW laser diode is focused with a low numerical aperture (NA) lens to create a radial trapping force within the beam. Opposite to optical tweezers, this low NA lens created an axial force that propels the cell to a predetermined target on the substrate rather than creating an axial trap. This portable laser guidance microscope can be used in any lab setting with little professional training required.

Ponthetta Mitchell
Research Interests: My research interests include cardiovascular diseases and Holistic medicine. My current research focus is in the area of re-entrant arrhythmias that occur at the healthy tissue-infarct/scar tissue border zone. I am currently investigating the electrical interaction of cardiac fibroblast and myocytes at the healty-infarct tissue border zone.