Fluorescence Imager for Microbial Monitoring of Habitat Surfaces

As next generation lunar missions and interplanetary human spaceflight grow closer, the ability to assess habitat surface microbial content quickly and accurately has become increasingly significant. Current state of the art technology relies on astronaut swabbing of surfaces and subsequently performing molecular analysis on the samples to determine the microbial burden. To alleviate this burden, Nanohmics Inc., proposes to continue advanced development of an autonomous, fluorescence imaging detector (AFID) for microbial mapping demonstrated during the Phase I program. The key components of the unmanned, aerial, 3D-sensing AFID system are a custom fluorescence detector with excitation sources controlled by embedded image acquisition and processing that uses spectral fingerprints and machine learning to differentiate between bacteria, fungi, and other organic material.The goal of the Phase II program will be design, optimization, and performance demonstration of the AFID system ability to generate a microorganism map of the total bioburden on simulated habitat surfaces relevant to future human spaceflight. The final AFID prototype will be advanced to TRL 5-6 over the course of the Phase II program with the ability to distinguish bacteria (detection threshold 500 CFU/100 cm2) and fungi (detection threshold 10 CFU/100 cm2) which meet the pre-flight and in-flight microbial mapping microbial monitoring requirements as defined by the International Space Station Medical Operations Requirements Documents (ISS MORD). Currently microbial mapping relies on sampling surfaces and performing molecular processes on the samples to determine the microbial burden. Nanohmics proposes to create an autonomous, consumable-free microbial mapping system. The key components of the system are a fluorescence imager, an embedded image processor, and an unmanned aerial vehicle (UAV) platform. Existing commercial systems that use fluorescence to measure microbial concentration are not well suited to this application. Systems designed to measure large areas can only measure high concentrations (≥10,000 CFU/g) of a limited number of bacteria. Systems designed to measure small concentrations of microorganisms can only image small areas (5mm x 5mm). Nanohmics proposes to design a fluorescence imager that can measure low concentrations of bacteria and fungi over a large area (10cm x 10cm) by combining ultraviolet LEDs as an excitation source and an array of silicon photomultipliers as an emission detector. The goal of the program is to develop a system that can generate a map of the bioburden of space habitat without consumables or human intervention. In Phase I, the team demonstrated the feasibility of using COTS components to build a fluorescence detector that can measure the concentration of certain bacteria and fungi on relevant surfaces. In Phase II, the team will build a prototype microbial mapping system. This effort will include the optimization of the prototype design, and its fabrication and testing. The robust prototype will be flight tested on a UAV to demonstrate its capabilities. The team will engineer the prototype to be rugged and easily integrated, mechanically and electronically, as a standard airborne instrument, advancing it to TRL 6 and delivering it to NASA. To achieve this goal, Nanohmics proposes the following Phase II technical objectives: Measure the concentration of relevant bacteria and fungi on relevant surfaces with Nanohmics designed fluorescence detector Demonstrate methods to discriminate between bacteria, fungi, and other organic material using spectral finger printing and machine learning Deploy a prototype of a compact, large-area microbial detection device on a robotic platform to generate a map of microbial contamination Project deliverables: Kick-off meetings slides, Phase II progress reports, Prototype microbial mapping system.
Benefits: Numerous NASA applications benefit from ensuring proper disinfection of surfaces, particularly habitat protection applications. This technology would enable in-situ measurement of spacecraft, lander, rover, and instrument cleanliness. A fluorescence imager has multiple applications in the medical, defense, and industrial markets. This technology could be applied to ultraviolet (UV) light disinfection systems used in hospitals to reduce healthcare-associated infections (HAIs) to ensure proper disinfection and identify pathogens in the hospital. This technology could also be used for bio-agent sensing for defense applications.