Jean-Marie Parel - US grants

We are requesting funds to purchase instruments that will be used to improve our undergraduate biomedical optics laboratory and curriculum. Our overall objective is to develop a two-semester undergraduate laboratory course in optics and lasers emphasizing their applications in medicine to better train undergraduate students at solving practical design and engineering problems in biomedical optics. In addition to classical optical teaching experiments, the laboratory courses will include representative design problems in medical optic and laser applications, with an emphasis on medical laser and light delivery systems and laser-tissue interactions. The laboratory courses will serve as a practical yet instructional introduction to optics, fiber optics, lasers and their application in the medical sciences. The courses are intended for sophomore or junior undergraduate biomedical engineering students. By providing this introductory practical experience, we will be able to improve the content of two existing classes on biomedical optics currently offered to advanced undergraduate students. We expect that this project will improve the achievements of our undergraduate students later involved in design projects in biomedical optics and also serve as a model for undergraduate programs in biomedical optics currently being developed at other universities nationwide. The results of the project so be used to develop additional undergraduate teaching materials and exercises in biomedical optics that may be others outside of our institution.

DESCRIPTION (provided by applicant): The objective of the proposed collaborative program is to understand the relationship between the optical and mechanical properties of the crystalline lens and the amplitude of accommodation and its loss in presbyopia. The general application of these bioengineering studies is the development of suitable technology including devices and surgical procedures for the restoration of near vision to presbyopes, as well as the restoration of good visual performance to cataract patients. The specific aims of the proposed research are: 1. To measure the mechanical properties of the crystalline lens 2: To measure the mechanical properties of the lens capsule 3: To measure the mechanical properties of the zonules 4: To develop mechanical and optical instrumentation to simulate accommodation in explanted crystalline lenses of eye-bank eyes (lens stretcher) 5: To quantify changes in normal and refilled crystalline lens during simulated accommodation 6: To develop an opto-mechanical model of the lens during accommodation The static and dynamic lens mechanical properties will be measured as a function of age using a micro-Fourier rheometer. The mechanical properties of the capsule will be measured using a custom-made capsule stretching device. The mechanical properties of the zonules will be investigated using atomic force microscopy and tensiometry. An opto-mechanical lens stretching system will be constructed to simulate accommodation on human cadaver lens specimens that include the crystalline lens, lens capsule, zonules, ciliary body and sclera. The system will be used to measure and correlate stretching forces with changes in lens equatorial diameter, thickness, displacement, topography, power and aberrations during simulated accommodation as a function of age. The contribution of the lens capsule and zonules to the mechanics of accommodation will be quantified by conducting lens stretching experiments before and after lens refilling with injectable materials of controlled mechanical properties.

DESCRIPTION (provided by applicant): The objective of the proposed collaborative program is to understand the relationship between the optical and mechanical properties of the crystalline lens and the amplitude of accommodation and its loss in presbyopia. The general application of these bioengineering studies is the development of suitable technology including devices and surgical procedures for the restoration of near vision to presbyopes, as well as the restoration of good visual performance to cataract patients. The specific aims of the proposed research are: 1. To measure the mechanical properties of the crystalline lens 2: To measure the mechanical properties of the lens capsule 3: To measure the mechanical properties of the zonules 4: To develop mechanical and optical instrumentation to simulate accommodation in explanted crystalline lenses of eye-bank eyes (lens stretcher) 5: To quantify changes in normal and refilled crystalline lens during simulated accommodation 6: To develop an opto-mechanical model of the lens during accommodation The static and dynamic lens mechanical properties will be measured as a function of age using a micro-Fourier rheometer. The mechanical properties of the capsule will be measured using a custom-made capsule stretching device. The mechanical properties of the zonules will be investigated using atomic force microscopy and tensiometry. An opto-mechanical lens stretching system will be constructed to simulate accommodation on human cadaver lens specimens that include the crystalline lens, lens capsule, zonules, ciliary body and sclera. The system will be used to measure and correlate stretching forces with changes in lens equatorial diameter, thickness, displacement, topography, power and aberrations during simulated accommodation as a function of age. The contribution of the lens capsule and zonules to the mechanics of accommodation will be quantified by conducting lens stretching experiments before and after lens refilling with injectable materials of controlled mechanical properties.

This is a proposal to acquire an atomic force microscope (AFM) on an inverted optical microscope and to develop two AFM-related non-imaging instruments: one for measuring single-molecule force spectroscopy and inter-molecular forces; the other, for measuring elasticities of soft samples under physiological conditions at the nano-scale. Over the past 10 years, atomic force microscopy (AFM) has become an increasingly important tool in biological research. It has gained popularity in biological applications because, unlike electron microscopy, it can image samples under physiological conditions, including live cells undergoing biological processes. The AFM acquires a topographical image of the sample surface by raster scanning an atomically sharp probe over the sample. In addition to its different imaging modes, the AFM is a versatile instrument that can be applied as a nano-indenter and as a molecular force apparatus to probe the mechanical properties of the sample. As a nano-indenter, the AFM has provided direct measurements of the local viscoelastic properties of samples on the nanometer scale. As a molecular force apparatus, the AFM has been used to measure the unbinding force of individual ligand-receptor complexes and the unfolding of individual proteins. Another attractive feature of the AFM is that it can be readily combined with optical microscopy techniques such as FRET, FRAP, TIRF and confocal microscopy. By integrating optical microscopy and AFM into a single experimental platform, the optical image can be directly correlated with the AFM data, providing a powerful tool for studying biological process in situ and in real time.

The acquisition and development of these three instruments is the first step toward establishing an ultramicroscopy center at the university. The two instruments to be developed can be constructed very economically, based on the designs of existing AFMs from the principal investigator's laboratory; this will permit the commercial AFM to be dedicated to imaging applications. The commercial AFM will be the first imaging AFM in the South Florida area and will provide a much needed resource for the local research community. These instruments will provide valuable research opportunities for undergraduates and students from underrepresented groups as well as researchers from different disciplines within the university.