Conventional Sterilization Methods Research Articles

3-Sulfopropyl acrylate potassium-based polyelectrolyte hydrogels: sterilizable synthetic material for biomedical application.

Hydrogels are extensively used in the biomedical field due to their highly valued properties, biocompatibility and antimicrobial activity and resistance to rheological stress. However, determining an efficient sterilization protocol that does not compromise the functional properties of hydrogels is one of the challenges researchers face when developing a material for a medical application. In this work, conventional sterilization methods (steam-, radiation- and gas sterilization) were investigated regarding the influence on the degree of swelling, mechanical performance and chemical effects on the poly 3-sulfopropyl acrylate potassium (pAESO3) hydrogel, which is a promising representative for biomedical engineering applications. In summary, no significant changes in the gel properties were observed after sterilization, showing the potential of the selected hydrogel for biomedical applications.

Hydrogelation of Regenerated Silk Fibroin via Gamma Irradiation.

Gamma irradiation, which is one of the more conventional sterilization methods, was used to induce the hydrogelation of silk fibroin in this study. The physical and chemical characteristics of the irradiation-induced silk fibroin hydrogels were investigated. Silk fibroin solution with a concentration greater than 1 wt% formed hydrogel when irradiated by gamma rays at a dose of 25 or 50 kGy. The hydrogel induced by 50 kGy of radiation was more thermally stable at 80 °C than those induced by 25 kGy of radiation. When compared to the spontaneously formed hydrogels, the irradiated hydrogels contained a greater fraction of random coils and a lower fraction of β-sheets. This finding implies that gelation via gamma irradiation occurs via other processes, in addition to crystalline β-sheet formation, which is a well-established mechanism. Our observation suggests that crosslinking and chain scission via gamma irradiation could occur in parallel with the β-sheet formation. The irradiation-induced hydrogels were obtained when the solution concentration was adequate to support the radiation crosslinking of the silk fibroin chains. This work has, therefore, demonstrated that gamma irradiation can be employed as an alternative method to produce chemical-free, random coil-rich, and sterilized silk fibroin hydrogels for biomedical applications.

A review of conventional and emerging technologies for hydrogels sterilization

Hydrogels are extensively used in the biomedical field, as drug delivery systems, wound dressings, contact lenses or as scaffolds for tissue engineering. Due to their polymeric nature and the presence of high amounts of water in their structure, hydrogels generally present high sensitivity to terminal sterilization. The establishment of an efficient sterilization protocol that does not compromise the functional properties of the hydrogels is one of the challenges faced by researchers when developing a hydrogel for a specific application. Yet, until very recently this aspect was largely ignored in the literature. The present paper reviews the state of literature concerning hydrogels sterilization, compiling the main findings. Conventional terminal sterilization methods (heat sterilization, radiation sterilization, and gas sterilization) as well as emerging sterilization techniques (ozone, supercritical carbon dioxide) are covered. Considerations about aseptic processing are also included. Additionally, and as a framework, hydrogels’ polymeric materials, types of networks, and main biomedical applications are summarily described.

Effective control of antibiotic resistance using a sonication-based combinational treatment and its application to fresh food

Antibiotics have been widely used to treat several infectious diseases. However, the overuse of antibiotics has promoted the emergence and spread of antibiotic resistant bacteria (ARB) in various fields, including the food industry. In this study, the antimicrobial efficacies of two conventional sterilization methods, mild heat, and sonication, were evaluated and optimized to develop a new strategy against ARB. Simultaneous mild heat and sonication (HS) treatment led to a significant reduction in viable cell counts, achieving a 5.58-log reduction in 4 min. However, no remarkable decrease in viable cell counts was observed in individually treated groups. Interestingly, the release of antibiotic resistance genes (ARGs) increased in a time-dependent manner in the heat-treated and HS-treated groups. The inactivation levels of ARGs increased as the HS treatment time increased from 2 to 8 min, and most ARGs were degraded after 8 min. In contrast, no significant inactivation of ARGs was observed in the heat-treated and sonication-treated groups after 8 min. These results reveal the synergistic effect of the combination treatment in controlling not only ARB but also ARGs. Finally, on applying this newly developed combination treatment to fresh food (cherry tomato and carrot juice), 3.97- and 4.28-log microbial inactivation was achieved, respectively. In addition, combination treatment did not affect food quality during storage for 5 days. Moreover, HS treatment effectively inactivated ARGs in fresh food systems.

Biosynthesis of selenium nanoparticles of Monascus purpureus and their inhibition to Alicyclobacillus acidoterrestris

Alicyclobacillus acidoterrestris is a kind of acid-resistant and heat-resistant gram-positive bacteria which can produce undesirable odors, causing fruit juice spoilage. However, conventional industrial sterilization methods cannot kill this bacterium. Antimicrobial nanoparticles could serve as promising antibacterial agents to inhibit A. acidoterrestris. In this work, selenium nanoparticles (SeNPs) were produced in the fermentation process of a selenium-enriched strain Monascus purpureus 2322 which domesticated in laboratory and their antibacterial activity against A. acidoterrestris was investigated. The as synthesized SeNPs was around spherical with a diameter of approximately 48 nm. Moreover, SeNPs could severely damage the integrity of bacterial cell, resulting in the leakage of cellular contents. Therefore, A. acidoterrestris was inhibited in the presence of SeNPs. These results indicate that the generation of SeNPs by fermentation provides a new efficacious way for developing antibacterial agent against A. acidoterrestris.

Life cycle assessment and energy comparison of aseptic ohmic heating and appertization of chopped tomatoes with juice

The energy balance and life cycle assessment (LCA) of ohmic heating and appertization systems for processing of chopped tomatoes with juice (CTwJ) were evaluated. The data included in the study, such as processing conditions, energy consumption, and water use, were experimentally collected. The functional unit was considered to be 1 kg of packaged CTwJ. Six LCA impact assessment methodologies were evaluated for uncertainty analysis of selection of the impact assessment methodology. The energy requirement evaluation showed the highest energy consumption for appertization (156 kWh/t of product). The energy saving of the ohmic heating line compared to the appertization line is 102 kWh/t of the product (or 65% energy saving). The energy efficiencies of the appertization and ohmic heating lines are 25% and 77%, respectively. Regarding the environmental impact, CTwJ processing and packaging by appertization were higher than those of ohmic heating systems. In other words, CTwJ production by the ohmic heating system was more environmentally efficient. The tin production phase was the environmental hotspot in packaged CTwJ production by the appertization system; however, the agricultural phase of production was the hotspot in ohmic heating processing. The uncertainty analysis results indicated that the global warming potential for appertization of 1 kg of packaged CTwJ ranges from 4.13 to 4.44 kg CO2eq. In addition, the global warming potential of the ohmic heating system ranges from 2.50 to 2.54 kg CO2eq. This study highlights that ohmic heating presents a great alternative to conventional sterilization methods due to its low environmental impact and high energy efficiency.

Potential harmful of extracellular proteases secreted by Pseudomonas fluorescens W3 on milk quality

Pseudomonas fluorescens is one of the main psychrotrophic bacteria that endangers milk quality because they can secret heat-resistant extracellular enzymes. Pseudomonas fluorescens W3 from raw milk was used to analyze its heat resistance and harm on milk. Pseudomonas fluorescens W3 did not have heat resistance, and could be killed effectively by conventional milk sterilization methods. However, the protease secreted by W3 had heat resistance, and could continue to decompose casein after sterilization. The raw milk inoculated with Pseudomonas fluorescens W3 was preserved after UHT treatment, and a visual sediment appeared after 7 days of storage. The increase in free amino acid content also confirmed the breakdown of casein. It was discovered that in addition to the protease AprX, Pseudomonas fluorescens W3 could secrete a variety of other proteases, which could cause potential harm to the quality of dairy products. Novelty impact statement The protease secreted by Pseudomonas fluorescens W3 strain has a certain degree of heat resistance. We use proteomics technology to find that Pseudomonas fluorescens W3 strain can secrete a variety of proteases and peptidases, which harms the quality of dairy products.

Time-Modulated LF-Microwave Hybrid Plasma for Surface Sterilization

The plasma surface sterilization method has emerged as a new sterilization method for medical instruments with many advantages, including nontoxicity, short treatment time, and low thermal damage to the sterilized material, over conventional sterilization methods. In this study, low-frequency (LF)-microwave hybrid plasma is produced by irradiation of microwave to an LF plasma jet. This hybrid plasma is characterized by atmospheric-pressure nonthermal plasma with a large amount of reactive species and has been applied for plasma surface sterilization. To reduce the treatment temperature while maintaining the effect of surface sterilization for applicability to heat-sensitive materials, the LF-microwave hybrid plasma was modulated in time by using pulsed microwaves. It was found that the gas temperature of the LF-microwave hybrid plasma produced by pulsed microwaves can be much lower than that of the LF-microwave hybrid plasma produced by continuous microwaves. Moreover, the gas temperature of the plasma was found to depend on the pulsewidth and duty ratio of microwaves used to produce it even if the time-averaged microwave power remained constant. Analyses of the optical emission spectra and chemical indicator tests indicated that the number of reactive oxygen radicals produced in the LF-microwave hybrid plasma also depends on the pulsewidth and duty ratio of the microwaves. In addition, it was found that the dependence of the number of oxygen atoms produced in the LF-microwave hybrid plasma on the microwave pulsewidth is opposite to that of the gas temperature. Spore-forming bacteria ( Geobacillus stearothermophilus ) with a population of $2.4 \times 106$ CFU/ $0.25{''} \times 1.5$ ” in a paper strip were sterilized for 1 min at a treatment temperature of 82.43 °C using pulsed LF-microwave hybrid plasma. The temperature and time of sterilization with the pulsed LF-microwave hybrid plasma were found to be lower than those with continuous LF-microwave hybrid plasma.

High Hydrostatic Pressure as Sterilization Method for Drug-Loaded Intraocular Lenses.

Sterilization is a key step in the manufacturing of drug-loaded intraocular lenses (IOLs). Two of the most used methods to sterilize commercial IOLs are steam heat and gamma radiation. However, when the IOLs are loaded with drugs, the adequacy of those methods must be questioned because sterilization may affect the activity of the drugs and/or the drug release. Recently, high hydrostatic pressure (HHP), which is increasingly used in the food industry, has been applied in the sterilization of gels for medical applications. The objective of this work was to assess the performance of HHP in the sterilization of a commercial acrylic material used for the production of IOLs, both without and with loaded drugs. Bare samples and samples loaded with an antibiotic and two anti-inflammatories were tested, and the results were compared to those obtained with conventional sterilization methods. HHP not only sterilized highly contaminated samples but also enhanced drug loading and did not affect significantly the hydrogel properties. Gamma radiation degraded the drugs in solution; thus, it is adequate only for dry sample sterilization. Steam heat did not affect the release profiles but cannot be applied to temperature-sensitive drugs. We concluded that HHP may advantageously substitute steam heat and gamma radiation in the sterilization of drug-loaded IOLs.

Anticipating Xenogenic Pollution at the Source: Impact of Sterilizations on DNA Release From Microbial Cultures.

The dissemination of DNA and xenogenic elements across waterways is under scientific and public spotlight due to new gene-editing tools, such as do-it-yourself (DIY) CRISPR-Cas kits deployable at kitchen table. Over decades, prevention of spread of genetically modified organisms (GMOs), antimicrobial resistances (AMR), and pathogens from transgenic systems has focused on microbial inactivation. However, sterilization methods have not been assessed for DNA release and integrity. Here, we investigated the fate of intracellular DNA from cultures of model prokaryotic (Escherichia coli) and eukaryotic (Saccharomyces cerevisiae) cells that are traditionally used as microbial chassis for genetic modifications. DNA release was tracked during exposure of these cultures to conventional sterilization methods. Autoclaving, disinfection with glutaraldehyde, and microwaving are used to inactivate broths, healthcare equipment, and GMOs produced at kitchen table. DNA fragmentation and PCR-ability were measured on top of cell viability and morphology. Impact of these methods on DNA integrity was verified on a template of free λ DNA. Intense regular autoclaving (121°C, 20 min) resulted in the most severe DNA degradation and lowest household gene amplification capacity: 1.28 ± 0.11, 2.08 ± 0.03, and 4.96 ± 0.28 logs differences to the non-treated controls were measured from E. coli, S. cerevisiae, and λ DNA, respectively. Microwaving exerted strong DNA fragmentation after 100 s of exposure when free λ DNA was in solution (3.23 ± 0.06 logs difference) but a minor effect was observed when DNA was released from E. coli and S. cerevisiae (0.24 ± 0.14 and 1.32 ± 0.02 logs differences with the control, respectively). Glutaraldehyde prevented DNA leakage by preserving cell structures, while DNA integrity was not altered. The results show that current sterilization methods are effective on microorganism inactivation but do not safeguard an aqueous residue exempt of biologically reusable xenogenic material, being regular autoclaving the most severe DNA-affecting method. Reappraisal of sterilization methods is required along with risk assessment on the emission of DNA fragments in urban systems and nature.

Effects of UV Exposure Time on Nanofiber Wound Dressing Properties During Sterilization

Purpose Electrospinning and nanofiber-based products have become popular in many areas in recent years. The increase in product range has brought various necessities such as sterilization. Conventional sterilization methods can be applied to nanofiber-based products. However, their effects on different properties of nanofibers must be carefully evaluated.

Sterilization of hydrogels for biomedical applications: A review

Despite the beneficial properties and outstanding potential of hydrogels for biomedical applications, several unmet challenges must be overcome, especially regarding to their known sensitivity to conventional sterilization methods. It is crucial for any biomaterial to withstand an efficient sterilization to obtain approval from regulatory organizations and to safely proceed to clinical trials. Sterility assurance minimizes the incidence of medical device-related infections, which still constitute a major concern in health care. In this review, we provide a detailed and comprehensive description of the published work from the past decade regarding the effects of sterilization on different types of hydrogels for biomedical applications. Advances in hydrogel production methods with simultaneous sterilization are also reported. Terminal sterilization methods can induce negative or positive effects on several material properties (e.g., aspect, size, color, chemical structure, mechanical integrity, and biocompatibility). Due to the complexity of factors involved (e.g., material properties, drug stability, sterilization conditions, and parameters), it is important to note the virtual impossibility of predicting the outcome of sterilization methods to determine a set of universal rules. Each system requires case-by-case testing to select the most suitable, effective method that allows for the main properties to remain unaltered. The impact of sterilization methods on the intrinsic properties of these systems is understudied, and further research is needed. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2472-2492, 2018.

Investigating the Detrimental Effects of Low Pressure Plasma Sterilization on the Survival of Bacillus subtilis Spores Using Live Cell Microscopy.

Plasma sterilization is a promising alternative to conventional sterilization methods for industrial, clinical, and spaceflight purposes. Low pressure plasma (LPP) discharges contain a broad spectrum of active species, which lead to rapid microbial inactivation. To study the efficiency and mechanisms of sterilization by LPP, we use spores of the test organism Bacillus subtilis because of their extraordinary resistance against conventional sterilization procedures. We describe the production of B. subtilis spore monolayers, the sterilization process by low pressure plasma in a double inductively coupled plasma reactor, the characterization of spore morphology using scanning electron microscopy (SEM), and the analysis of germination and outgrowth of spores by live cell microscopy. A major target of plasma species is genomic material (DNA) and repair of plasma-induced DNA lesions upon spore revival is crucial for survival of the organism. Here, we study the germination capacity of spores and the role of DNA repair during spore germination and outgrowth after treatment with LPP by tracking fluorescently-labelled DNA repair proteins (RecA) with time-resolved confocal fluorescence microscopy. Treated and untreated spore monolayers are activated for germination and visualized with an inverted confocal live cell microscope over time to follow the reaction of individual spores. Our observations reveal that the fraction of germinating and outgrowing spores is dependent on the duration of LPP-treatment reaching a minimum after 120 s. RecA-YFP (yellow fluorescence protein) fluorescence was detected only in few spores and developed in all outgrowing cells with a slight elevation in LPP-treated spores. Moreover, some of the vegetative bacteria derived from LPP-treated spores showed an increase in cytoplasm and tended to lyse. The described methods for analysis of individual spores could be exemplary for the study of other aspects of spore germination and outgrowth.

Inactivation of Staphylococcus aureus in water by pulsed spark discharge

A pulsed spark plasma discharge system was developed and tested as an energy efficient water sterilization method. A 5 log10 reduction on Staphylococcus aureus concentration of 108 CFU/ml was obtained. Complete inactivation was achieved for concentration of 106 CFU/ml. Of the various factors generated by an underwater spark discharge, ultraviolet radiation plays a major role. The inactivation was completely suppressed by the addition of 30 mg/L of a soluble sunscreen, Benzophenone-9. Results obtained using the pulsed spark plasma discharge showed that this system has several advantages, such as high energy efficiency, absence of harmful by-products and portability, over the conventional sterilization methods.

Microbial consortia in meat processing environments

Microbial contamination in food processing plants can play a fundamental role in food quality and safety. The description of the microbial consortia in the meat processing environment is important since it is a first step in understanding possible routes of product contamination. Furthermore, it may contribute in the development of sanitation programs for effective pathogen removal. The purpose of this study was to characterize the type of microbiota in the environment of meat processing plants: the microbiota of three different meat plants was studied by both traditional and molecular methods (PCR-DGGE) in two different periods. Different levels of contamination emerged between the three plants as well as between the two sampling periods. Conventional methods of killing free-living bacteria through antimicrobial agents and disinfection are often ineffective against bacteria within a biofilm. The use of gas-discharge plasmas potentially can offer a good alternative to conventional sterilization methods. The purpose of this study was to measure the effectiveness of Atmospheric Pressure Plasma (APP) surface treatments against bacteria in biofilms. Biofilms produced by three different L. monocytogenes strains on stainless steel surface were subjected to three different conditions (power, exposure time) of APP. Our results showed how most of the culturable cells are inactivated after the Plasma exposure but the RNA analysis by qPCR highlighted the entrance of the cells in the viable-but non culturable (VBNC) state, confirming the hypothesis that cells are damaged after plasma treatment, but in a first step, still remain alive. The understanding of the effects of APP on the L. monocytogenes biofilm can improve the development of sanitation programs with the use of APP for effective pathogen removal.

Hemocompatibility and surface properties of bovine pericardial patches: Effects of gamma sterilization

In the present study, the effects of sterilization by gamma irradiation on hemocompatibility and surface properties of the acellular bovine pericardium, a versatile biomaterial were investigated. The native bovine pericardium was decellularized using SDS for one group, Triton-X 100 for other group and subsequently sterilized with gamma rays. The chemical composition was confirmed using infrared spectroscopy, morphological changes by scanning electron microscopy and in vitro hemo-compatibility studies were conducted. Our results indicated that gamma ray sterilization process had significant effects on the processed bovine pericardium. A confirmed decrease in hemocompatibiity, with changes in the collagen organization and fragmentation was noticed. Conventional sterilization methods are not suitable for the targeted biomaterial since the proteins in biomaterial get denatured, compromise their physicochemical properties and hemocompatibiity.

Chitosan nanogels for biomedical applications: Choosing a suitable sterilization method

Event Abstract Back to Event Chitosan nanogels for biomedical applications: Choosing a suitable sterilization method Raquel Galante1, 2, Irene Satiko1, Nádia A. Bou-Chacra1, Rogério Colaço2, Ana P. Serro2, 3 and Terezinha J. Pinto1 1 Faculdade de Ciências Farmacêuticas - Universidade de São Paulo, Departamento de Farmácia, Brazil 2 Instituto Superior Técnico - Universidade de Lisboa, Centro de Química Estrutural, Portugal 3 Instituto Superior de Ciências da Saúde Egas Moniz, Centro De Investigação Interdisciplinar Egas Moniz, Portugal Introduction: Nanostructured hydrogels have been subject of detailed studies aiming a wide range of biomedical and pharmaceutical applications. Sterilization is a crucial step in the development of this type of materials[1]. Although often effective, the conventional sterilization methods may change the physico-chemical properties of the gels and their biocompatibility, compromising their functionality[1],[2]. The main goal of this work is to study the effect of different sterilization methods on the intrinsic properties of chitosan nanogels. In addition to conventional methods (autoclave and gamma radiation) a recent and promising ozone-based method of sterilization, still in the development phase, was also evaluated to assess its applicability to the studied material. Method: A model chitosan-based nanostructured hydrogel (nanogel), with broad spectrum of possible applications was produced by ionic gelation, using sodium tripolyphosphate (TPP) as a crosslinking agent. The nanogel was sterilized by autoclave, gamma irradiation and by ozone gas in the absence and in the presence of protective sugars (dextrose and mannitol). Sterilization parameters, such as temperature, time of exposure and irradiation dose, were varied in order to study their effect. A complete characterization protocol was carried out, before and after each sterilization method, as follows: size, dispersion and zeta potential alterations where analyzed by Zetasizer measurements; surface topography and morphology were studied by Scanning Electronic Microscopy and physicochemical alterations were monitored by Fourier Transform Infrared Spectroscopy analysis. In order to ensure the effectiveness of the ozone method, sterility efficacy tests were carried out by purposely contaminating the samples with different loads of a microorganism known to be resistant to the technique. Results and Discussion: Exposing the nanogel, as it is, to gamma rays, let to the immediately visible formation of sediments. Although the UV-Vis spectra data did not show significant alterations, the size and zeta potential measurements displayed significant effects on Z-average size, PDI and zeta potential values, thus resulting in a degraded nanogel.Upon the sugar addition (D-glucose and mannitol) to the nanogel suspension, the results showed a substantial increase of the resistance to irradiation.The variation of average particle due to gamma rays irradiation can be observed in Figure 1, for all the studied conditions. In both cases, size, PDI, and zeta potential values variations were significantly reduced.Concerning the ozone gas method, the nanogel revealed a promising resistance to the ozonation, having shown no major sings of alteration in size, zeta potential and PDI..The variation of average particle due to ozonation can be observed in Figure 2, for all the studied conditions. Conclusions: Sterilization of soft polymeric biomaterials such as nanogels is a challenging task. The information available in the literature about the sterilization of chitosan nanogels is scarce, which reinforces the importance of this work. It was found that the nanogel resistance to irradiation increases considerably in the presence of protective sugars. The results obtained are also promising with regard to the possible applicability of the ozone sterilization since the nanogel seems to withstand the method without displaying significant adverse effects. Figure 1: Average particle size before and after sterilization by gamma irradiation Figure 2: Average particle size before and after sterilization by ozone gas. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Fundação para a Ciência e Tecnologia (FCT), Project SurfLenses - MERA-NET; A special thanks to Dr. Pablo Vásquez from IPEN (Instituto de Pesquisas Energéticas e Nucleares)

Sterilization effect of nitrogen oxide radicals generated by microwave plasma using air

Plasma sterilization has attracted attention as a safe and low cost sterilization method compared to conventional sterilization methods such as EOG (ethylene oxide gas) sterilization and high-pressure steam sterilization. In this research, a plasma is generated by irradiating air with microwaves. Sterilization is caused by 0-radicals and NO-radicals. In order to carry out sterilization efficiently, optimal setting of equipment conditions is required. The pressure required for optimal conditions of the equipment, the microwave output, and the equipment used have been examined. A biological indicator (BI), Geobacillus stearothermophilus (ATCC7953), was used. It was found that sterilization was successful when the pressure in the vacuum chamber for microwave output of 280 W was 60 Pa.

Depyrogenation by the Flowing Afterglow of a Reduced‐Pressure N2–O2 Discharge (Gaseous Plasma Treatment)

The presence of pyrogens in the human body can activate the immune system leading to pathological effects, such as fever, tissue damage, septic shock, possibly even death. This is a major concern in the pharmaceutical field where injectable solutions are widely used. The main pyrogens are the lipopolysaccharide (LPS) molecules from Gram‐negative bacteria and the lipoteichoic acid (LTA) from Gram‐positive bacteria. Conventional sterilization methods cannot fully inactivate these molecules. A significant decrease of the pyrogenic activity of both LPS and LTA is obtained after exposure to the flowing afterglow of a N2–O2 discharge. We also investigated the level of pyrogenic activity ensuing from the inactivation of bacterial spores by the flowing afterglow.

Peracetic Acid: A Practical Agent for Sterilizing Heat-Labile Polymeric Tissue-Engineering Scaffolds

Advanced biomaterials and sophisticated processing technologies aim at fabricating tissue-engineering scaffolds that can predictably interact within a biological environment at the cellular level. Sterilization of such scaffolds is at the core of patient safety and is an important regulatory issue that needs to be addressed before clinical translation. In addition, it is crucial that meticulously engineered micro- and nano- structures are preserved after sterilization. Conventional sterilization methods involving heat, steam, and radiation are not compatible with engineered polymeric systems because of scaffold degradation and loss of architecture. Using electrospun scaffolds made from polycaprolactone, a low melting polymer, and employing spores of Bacillus atrophaeus as biological indicators, we compared ethylene oxide, autoclaving and 80% ethanol to a known chemical sterilant, peracetic acid (PAA), for their ability to sterilize as well as their effects on scaffold properties. PAA diluted in 20% ethanol to 1000 ppm or above sterilized electrospun scaffolds in 15 min at room temperature while maintaining nano-architecture and mechanical properties. Scaffolds treated with PAA at 5000 ppm were rendered hydrophilic, with contact angles reduced to 0°. Therefore, PAA can provide economical, rapid, and effective sterilization of heat-sensitive polymeric electrospun scaffolds that are used in tissue engineering.