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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS2000

Mechanical properties of a biodegradable bone regeneration scaffold

Poly (Propylene Fumarate) (PPF), a novel, bulk erosion, biodegradable polymer, has been shown to have osteoconductive effects in vivo when used as a bone regeneration scaffold (Peter, S. J., Suggs, L. J., Yaszemski, M. J., Engel, P. S., and Mikos, A. J., 1999, J. Biomater. Sci. Polym. Ed., 10, pp. 363-373). The material properties of the polymer allow it to be injected into irregularly shaped voids in vivo and provide mechanical stability as well as function as a bone regeneration scaffold. We fabricated a series of biomaterial composites, comprised of varying quantities of PPF, NaCl and beta-tricalcium phosphate (beta-TCP), into the shape of right circular cylinders and tested the mechanical properties in four-point bending and compression. The mean modulus of elasticity in compression (Ec) was 1204.2 MPa (SD 32.2) and the mean modulus of elasticity in bending (Eb) was 1274.7 MPa (SD 125.7). All of the moduli were on the order of magnitude of trabecular bone. Changing the level of NaCl from 20 to 40 percent, by mass, did not decrease Ec and Eb significantly, but did decrease bending and compressive strength significantly. Increasing the beta-TCP from 0.25 g/g PPF to 0.5 g/g PPF increased all of the measured mechanical properties of PPF/NVP composites. These results indicate that this biodegradable polymer composite is an attractive candidate for use as a replacement scaffold for trabecular bone.

NASA Discipline Cell Biology↗
NASA NTRS2023

Fighting Wildfires Using UAVs Using Autonomous Biodegradable Self-sacrificing (ABS) Drones to Combat Large Wildfires with the Assistance of Satellite Imagery

As wildfires continue to increase in number and severity due to global warming, firefighters are having a harder time combating them safely. This paper examines the application of Autonomous Biodegradable Self-sacrificing (ABS) Drones as a method of fighting wildfires that decreases the number of lives put at risk and proposes a sustainable alternative to current aerial firefighting methods. When a fire is detected or predicted through satellite imagery, ABS Drones are dispatched from firefighting stations or aerial watchtowers to fly towards designated areas and release fire retardants, preventing the fire from further spreading. The most significant feature of this drone is its ability to complete its mission without having to worry about returning safely because ABS Drones are designed to crash and release fire retardants, while not further harming the environment with water-based lithium-ion batteries and a biodegradable body. ABS Drones make it safer for firefighters as it gives firefighters one less life-threatening task to do and allows them to focus on putting out the fire. This solution aims to tackle the unpredictable nature of wildfires that often threaten the safety of firefighters and civilian communities.

ABS Drones↗
DOE OSTI2025

Production of high-performance biodegradable polyurethane products made from algae precursors

We successfully developed and scaled the production of high-performance, fully biodegradable thermoplastic polyurethanes (TPUs) derived from algae-based precursors. By employing innovative flow chemistry and chemo-enzymatic methodologies, the research team produced materials with up to 100% bio-based content that match or exceed the mechanical properties of traditional petroleum-based plastics. These algae-derived TPUs were proven to be fully home-compostable, achieving over 90% decomposition within 110 to 120 days while demonstrating practical advantages such as reduced solvent requirements in fabric coating applications.

36 MATERIALS SCIENCE↗
NASA NTRS1997

Bone formation by three-dimensional stromal osteoblast culture in biodegradable polymer scaffolds

Bone formation was investigated in vitro by culturing stromal osteoblasts in three-dimensional (3-D), biodegradable poly(DL-lactic-co-glycolic acid) foams. Three polymer foam pore sizes, ranging from 150-300, 300-500, and 500-710 microns, and two different cell seeding densities, 6.83 x 10(5) cells/cm2 and 22.1 x 10(5) cells/cm2, were examined over a 56-day culture period. The polymer foams supported the proliferation of seeded osteoblasts as well as their differentiated function, as demonstrated by high alkaline phosphatase activity and deposition of a mineralized matrix by the cells. Cell number, alkaline phosphatase activity, and mineral deposition increased significantly over time for all the polymer foams. Osteoblast foam constructs created by seeding 6.83 x 10(5) cells/cm2 on foams with 300-500 microns pores resulted in a cell density of 4.63 x 10(5) cells/cm2 after 1 day in culture; they had alkaline phosphatase activities of 4.28 x 10(-7) and 2.91 x 10(-6) mumol/cell/min on Days 7 and 28, respectively; and they had a cell density that increased to 18.7 x 10(5) cells/cm2 by Day 56. For the same constructs, the mineralized matrix reached a maximum penetration depth of 240 microns from the top surface of the foam and a value of 0.083 mm for mineralized tissue volume per unit of cross sectional area. Seeding density was an important parameter for the constructs, but pore size over the range tested did not affect cell proliferation or function. This study suggests the feasibility of using poly(alpha-hydroxy ester) foams as scaffolding materials for the transplantation of autogenous osteoblasts to regenerate bone tissue.

Non-NASA Center↗
NASA NTRS1973

The use of near-infrared photography for biodegradable pollution monitoring of tidal rivers

On October 2, 1972, a pattern of chlorophyll a containing phytoplankton (algae) was detected from 3-km altitude in a series of near-infrared photographs of the Potomac River 'Salt Wedge Area.' Densitometer traces over the film images, related to in situ measurements of chlorophyll a concentrations that varied from 4 to more than 3000 micrograms/liter, revealed a phytoplankton 'bloom' threshold in the near infrared between the concentration of 34 and 51 micrograms/liter. The photography also revealed bottom features through two meters of water and made it possible to integrate chlorophyll a concentrations over a 16 sq km area to demonstrate this remote sensing technique for biodegradable pollution monitoring.

Bressette, W. E.↗
NASA NTRS1975

Biodegradation of rocket propellent waste, ammonium perchlorate

The impact of the biodegradation rate of ammonium perchlorate on the environment was studied in terms of growth, metabolic rate, and total biomass of selected animal and plant species. Brief methodology and detailed results are presented.

Naqui, S. M. Z.↗
NASA NTRS1998

Three-dimensional culture of rat calvarial osteoblasts in porous biodegradable polymers

Neonatal rat calvarial osteoblasts were cultured in 90% porous, 75:25 poly(DL-lactic-co-glycolic acid) (PLGA) foam scaffolds for up to 56 days to examine the effects of the cell seeding density, scaffold pore size, and foam thickness on the proliferation and function of the cells in this three-dimensional environment. Osteoblasts were seeded at either 11.1 x 10(5) or 22.1 x 10(5) cells per cm2 onto PLGA scaffolds having pore sizes in the range of 150-300 or 500-710 microm with a thickness of either 1.9 or 3.2 mm. After 1 day in culture, 75.6 and 68.6% of the seeded cells attached and proliferated on the 1.9 mm thick scaffolds of 150-300 microm pore size for the low and high seeding densities, respectively. The number of osteoblasts continued to increase throughout the study and eventually leveled off near 56 days, as indicated by a quantitative DNA assay. Osteoblast/foam constructs with a low cell seeding density achieved comparable DNA content and alkaline phosphatase (ALPase) activity after 14 days, and mineralization results after 56 days to those with a high cell seeding density. A maximum penetration depth of osseous tissue of 220+/-40 microm was reached after 56 days in the osteoblast/foam constructs of 150-300 microm pore size initially seeded with a high cell density. For constructs of 500-710 microm pore size, the penetration depth was 190+/-40 microm under the same conditions. Scaffold pore size and thickness did not significantly affect the proliferation or function of osteoblasts as demonstrated by DNA content, ALPase activity, and mineralized tissue formation. These data show that comparable bone-like tissues can be engineered in vitro over a 56 day period using different rat calvarial osteoblast seeding densities onto biodegradable polymer scaffolds with pore sizes in the range of 150-710 microm. When compared with the results of a previous study where similar polymer scaffolds were seeded and cultured with marrow stromal cells, this study demonstrates that PLGA foams are suitable substrates for osteoblast growth and differentiated function independent of cell source.

Non-NASA Center↗
DOE OSTI2025

Upcycling of Waste Plastics into Carboxylic Acids for Biodegradable Surfactants

This work outlines a process for producing high‐purity (>95%) carboxylate surfactants from post‐consumer recycled high‐density polyethylene (PCR‐HDPE). The approach involves the thermal depolymerization of PCR‐HDPE via pyrolysis, followed by fractional distillation to isolate C9–C14 olefins. These olefins undergo hydroformylation using cobalt carbonyl catalysts to generate aldehydes, which are subsequently oxidized to carboxylic acids using Pinnick oxidation under mild aqueous‐phase conditions. Neutralization of the resulting carboxylic acids with sodium hydroxide produces plastic‐derived carboxylate surfactants (PDCs) in the form of sodium carboxylates. Subsequent purification steps ensure surfactant‐grade purity and enable accurate assessment of physicochemical properties. The resulting PDCs are evaluated for critical micelle concentration (CMC), foamability, surface tension reduction, and calcium ion tolerance, demonstrating competitive behavior with conventional anionic carboxylate surfactants. This route provides a sustainable alternative for surfactant production, reducing reliance on fossil‐derived feedstocks and valorizing plastic waste streams through chemical upcycling.

Biodegradable surfactants↗
DOE OSTI2026

Elucidating biodegradation of dimethyl terephthalate by two Rhodococcus strains for its valorization applications

Dimethyl terephthalate (DMT) serves as the precursor in the production of polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate. The widespread use of DMT in the polymer industry and its ubiquitous existence in end products raise alarms about its potential harm to humans and animals. DMT can enter the environment through the degradation of polymers and their end products, and cause endocrine disruption, oxidative stress, and an elevated risk of cancer. In recent years, DMT has also gained renewed interest in its potential for plastic recycling and upcycling. In this study, we identified two strains of Rhodococcus that possess DMT-degrading capabilities and utilized transcriptomic analysis and gene knockout to elucidate the mechanisms of DMT degradation. R. opacus PD630 and R. jostii RPET were found to convert up to 1 g/L DMT into mono-methyl terephthalate (MMT). A putative DMTase (RS34275) was identified for this conversion. R. jostii RPET also demonstrates the ability to convert DMT into MMT and to utilize MMT for its cellular growth via the terephthalate pathway. A putative MMTase (RS21885) as the sole enzyme was identified for the conversion of MMT into terephthalate in the RPET strain. In addition, we successfully produced lycopene and lipids from an engineered RPET strain using DMT as a substrate. Our findings will facilitate future DMT bioremediation and bio-upcycling of DMT-associated plastics, enabling the production of value-added products.

Biodegradation↗
NASA NTRS1996

Biodegradation of Trihalomethanes and Other Halogenated Aliphatic Compounds

The biological dehalogenation of common water pollutants such as trichloromethane (chloroform) and other halogenated aliphatic compounds was the subject of this project. Samples from diverse water environments such as from groundwater contaminated with halogenated compounds and wastewaters from regional treatment plants were studied to identify conditions that favor certain dehalogenation reactions over others. Gene probe analyses of DNA extracted from the dichlormethane-degrading wastewater indicated the presence of the gene coding for dichloromethane dehalogenase, indicating the genetic basis for the dechlorination activity observed. These studies indicate that methanogenic bacteria are the organisms responsible for the chloroform dechlorination. Dechlorination of a common chlorofluorocarbon (CFC-11) was identified in samples taken from a regional aquifer contaminated with halogenated aliphatic compounds.

HALOGENATED ALIPHATC HYDROCARBONS↗
NASA NTRS2003

Biodegradation pathway of an anionic surfactant (Igepon TC-42) during recycling waste water through plant hydroponics for advanced life support during long-duration space missions

The degradation of an anionic surfactant (Igepon TC-42) was investigated as part of an integrated study of direct recycling of human hygiene water through hydroponic plant growth systems. Several chemical approaches were developed to characterize the degradation of Igepon and to measure the accumulation of intermediates such as fatty acids and methyl taurine. Igepon was rapidly degraded as indicated by the reduction of methylene blue active substances (MBAS) and component fatty acids. The Igepon degradation rate continued to increase over a period of several weeks following repeated daily exposure to 18 micrograms/l Igepon. The accumulation of free fatty acids and methyl taurine was also observed during decomposition of Igepon. The concentration of methyl taurine was below detection limit (0.2 nmol/ml) during the slow phase of Igepon degradation, and increased to 1-2 nmol/ml during the phase of rapid degradation. These findings support a degradation pathway involving initial hydrolysis of amide to release fatty acids and methyl taurine, and subsequent degradation of these intermediates. Published by Elsevier Science Ltd on behalf of COSPAR.

NASA Discipline Life Support Systems↗
NASA NTRS2002

Effect of hydraulic retention time on inorganic nutrient recovery and biodegradable organics removal in a biofilm reactor treating plant biomass leachate

A fixed-film (biofilm) reactor was designed and its performance was determined at various retention times. The goal was to find the optimal retention time for recycling plant nutrients in an advanced life support system, to minimize the size, mass, and volume (hold-up) of a production model. The prototype reactor was tested with aqueous leachate from wheat crop residue at 24, 12, 6, and 3 h hydraulic retention times (HRTs). Biochemical oxygen demand (BOD), nitrates and other plant nutrients, carbohydrates, total phenolics, and microbial counts were monitored to characterize reactor performance. BOD removal decreased significantly from 92% at the 24 h HRT to 73% at 3 h. Removal of phenolics was 62% at the 24 h retention time, but 37% at 3 h. Dissolved oxygen concentrations, nitric acid consumption, and calcium and magnesium removals were also affected by HRT. Carbohydrate removals, carbon dioxide (CO2) productions, denitrification, potassium concentrations, and microbial counts were not affected by different retention times. A 6 h HRT will be used in future studies to determine the suitability of the bioreactor effluent for hydroponic plant production.

NASA Center KSC↗
NASA NTRS2001

Effect of convection on osteoblastic cell growth and function in biodegradable polymer foam scaffolds

Culture of seeded osteoblastic cells in three-dimensional osteoconductive scaffolds in vitro is a promising approach to produce an osteoinductive material for repair of bone defects. However, culture of cells in scaffolds sufficiently large to bridge critical-sized defects is a challenge for tissue engineers. Diffusion may not be sufficient to supply nutrients into large scaffolds and consequently cells may grow preferentially at the periphery under static culture conditions. Three alternative culturing schemes that convect media were considered: a spinner flask, a rotary vessel, and a perfusion flow system. Poly(DL-lactic-co-glycolic acid) (PLGA) foam discs (12.7 mm diameter, 6.0 mm thick, 78.8% porous) were seeded with osteoblastic marrow stromal cells and cultured in the presence of dexamethasone and L-ascorbic acid for 7 and 14 days. Cell numbers per foam were found to be similar with all culturing schemes indicating that cell growth could not be enhanced by convection, but histological analysis indicated that the rotary vessel and flow system produced a more uniform distribution of cells throughout the foams. Alkaline phosphatase (ALP) activity per cell was higher with culture in the flow system and spinner flask after 7 days, while no differences in osteocalcin (OC) activity per cell were observed among culturing methods after 14 days in culture. Based on the higher ALP activity and better cell uniformity throughout the cultured foams, the flow system appears to be the superior culturing method, although equally important is the fact that in none of the tests did any of the alternative culturing techniques underperform the static controls. Thus, this study demonstrates that culturing techniques that utilize fluid flow, and in particular the flow perfusion system, improve the properties of the seeded cells over those maintained in static culture.

NASA Discipline Cell Biology↗