A Phase 3 interventional study of Silver Nanoparticle Gel and alcohol-based hand gel in Healthy, sponsored by Madigan Army Medical Center. Terminated at 1 site in United States. Open to participants aged 19 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-01-23.
Sponsored by Madigan Army Medical Center · Phase 3, Interventional, and Screening
The purpose of this pilot study is to compare the antimicrobial efficacy of silver nanoparticle gel to a commercialized alcohol-based hand gel on bacterial counts isolated from the hands of 40 volunteers seeded with Serratia marcescens, a surrogate microbial marker. Specific aims of this study are: Aim #1: Compare the immediate antimicrobial efficacy of a one-time application of silver nanoparticle gel (SilvaSorb , AcryMed, Inc., Portland, OR) versus an alcohol-based hand gel (Purell, GoJo Industries, Akron, OH) in reducing transient bacterial counts isolated from hands seeded with S. marcescens.
Aim # 2: Compare the persistent antimicrobial efficacy of a one-time application of silver nanoparticle gel (SilvaSorb) versus an alcohol-based hand gel (Purell) over a 10 minute time frame in producing a persistent reduction on transient bacterial counts isolated from hands seeded with S. marcescens.
Aim # 3: Compare user acceptability of silver nanoparticle gel (SilvaSorb) versus an alcohol-based hand gel (Purell) using a self-assessment questionnaire.
The objective of this randomized controlled, double blinded, 2x3 experimental study is to evaluate the antimicrobial efficacy of silver nanoparticle gel compared to an alcohol-based hand gel on bacterial counts isolated from the hands of 40 healthy, adult, military student volunteers. The study will be conducted in two phases: the first phase will consist of a methods development period and the second phase will consist of the formal pilot study. For phase I, the first four participants from the sample pool will be assigned into one of two groups (nano-silver gel or alcohol-based gel) whereas in Phase II, the participants will be randomized into one of two groups. Participants in both phases will follow a 7 day washout period where subjects will refrain from using antimicrobial products for a week prior to testing. Testing of participants in both phases will start with a baseline bacterial hand count. This will be accomplished by using a surrogate biomarker (S. Marcescens). This microorganism was selected because it is considered the standard surrogate marker to be used in hand hygiene evaluations and because it produces a characteristic red colony that is easily distinguishable from normal microbial populations of the hands making colony counting more accurate. Sampling of bacterial flora will be accomplished utilizing an established "modified glove juice" technique in which the participant's dominant hand is placed into a large sterile bag containing a sampling solution, which removes the surrogate bacteria. Once baseline samples have been collected, all participants will then complete two additional random ordered timed conditions involving the surrogate biomarker and one of the two test gels. For each test condition, five mL of solution will be withdrawn from the collection bag, diluted, plated, and incubated for 36 hours. For the immediate efficacy testing, a glove juice sampling will be obtained after a 1 minute application of the gel. For the persistent efficacy testing, a glove juice sampling will be obtained after a 10 minute application of the gel. To ensure the biomarker has been removed, all subjects will wash hands with a 70% ethanol surgical handwash. The use of an UV-C light will also be implemented for 20 seconds as an additional precaution. Participants in phase I will have an additional glove juice sampling at the end of degerming to validate the protocol. All participants will end the study by completing a 4 question visual analog questionnaire to determine user acceptability of the gels. The percent difference of total bacterial counts from baseline will be used as the outcome variable. An unpaired Student's t-test (or an appropriate non-parametric test) will be used for data analysis for each of the study aims.
Madigan Army Medical Center is the lead sponsor of 26 studies on the registry; 4 are open to participants now.
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Silver Nanoparticle Gel (SilvaSorb, AcryMed, Inc., Portland, OR)
Drug: Silver Nanoparticle Gel
Alcohol-based hand gel (Purell, GoJo Industries, Akron, OH)
Drug: alcohol-based hand gel
SilvaSorb® gel applied topically to the hands with a limited exposure time of 10 minutes
Also known as: SilvaSorb® gel
Purell gel applied topically to the hands with a limited exposure time of 10 minutes
Also known as: Purell
Microbial Count at Baseline
Subjects' hands are contaminated with 1.5 milliliters (mL) aliquot of S. marcescens which is then distributed evenly over both hands. A 30 second massage with bacteria followed by one minute of timed air drying takes place prior to the modified glove juice sampling procedure. Subject's dominant hand is placed into a sterile 1 liter polyethylene bag with 75 mL of sampling solution. Hand is removed after 60 seconds of massage and 5 mL of juice is retrieved, diluted 1:10 within 5 minutes, and plated in duplicate on trypticase soy agar. Samples are transported in bio-transport container to the lab where they are incubated aerobically at 36 degrees Centigrade for 36 hours.
Time frame: Baseline
Microbial Count - Persistent Effect
Microbial count of hands seeded with S. marcescens after ten minutes of exposure and treatment with an antimicrobial gel. Same modified glove juice sampling technique was used and 1.5 milliliters of juice was removed, diluted, and plated for incubation.
Time frame: 10 minutes
Microbial Count - Immediate Effect
Subjects underwent the modified glove juice technique after seeding of hands with S. marcescens bacteria for 1 minute followed by application of one of the two antimicrobial gels; a 1.5 milliliter sample of the juice was collected after 1 minute. The procedure was repeated for each of the two gels, random order assigned.
Time frame: 1 minute
User Acceptability
User Acceptability Questionnaire - Self-assessment. Investigator-developed instrument that included 4 questions regarding the specific hand gel product applied to the participant's hands: 1) I would rate my acceptance of this product as?; 2) I would consider using this product again?; 3) I would rate my confidence in this product as?; and 4) I would recommend using this product to my co-workers?. Scale had anchors of 1 (least acceptable) to 10 (most acceptable). Total score was the sum of scores for each of the 4 questions; range was 4 to 40. there were no subscales. A score of 4 demonstrated least acceptance and score of 40 demonstrated highest acceptance.
Time frame: 2 hours
We assessed 24 subjects for eligibility. 2 did not meet inclusion criteria which left us with 22 subjects who were randomized into two groups; 11 in each group.
| Milestone | Nano-silver Gel | Alcohol-based Gel |
|---|---|---|
| Started | 11 | 11 |
| Completed | 11 | 11 |
| Not completed | 0 | 0 |
Subjects' hands are contaminated with 1.5 milliliters (mL) aliquot of S. marcescens which is then distributed evenly over both hands. A 30 second massage with bacteria followed by one minute of timed air drying takes place prior to the modified glove juice sampling procedure. Subject's dominant hand is placed into a sterile 1 liter polyethylene bag with 75 mL of sampling solution. Hand is removed after 60 seconds of massage and 5 mL of juice is retrieved, diluted 1:10 within 5 minutes, and plated in duplicate on trypticase soy agar. Samples are transported in bio-transport container to the lab where they are incubated aerobically at 36 degrees Centigrade for 36 hours.
| CFU/mL | Nano-silver Gel | Alcohol-based Gel |
|---|---|---|
| Microbial Count at Baseline | 105 ± 7.1 | 107 ± 8.1 |
User Acceptability Questionnaire - Self-assessment. Investigator-developed instrument that included 4 questions regarding the specific hand gel product applied to the participant's hands: 1) I would rate my acceptance of this product as?; 2) I would consider using this product again?; 3) I would rate my confidence in this product as?; and 4) I would recommend using this product to my co-workers?. Scale had anchors of 1 (least acceptable) to 10 (most acceptable). Total score was the sum of scores for each of the 4 questions; range was 4 to 40. there were no subscales. A score of 4 demonstrated least acceptance and score of 40 demonstrated highest acceptance.
| score on a scale | Nano-silver Gel | Alcohol-based Gel |
|---|---|---|
| User Acceptability | 27 ± 5.7 | 33 ± 5.6 |
Microbial count of hands seeded with S. marcescens after ten minutes of exposure and treatment with an antimicrobial gel. Same modified glove juice sampling technique was used and 1.5 milliliters of juice was removed, diluted, and plated for incubation.
| CFU/mL | Nano-silver Gel | Alcohol-based Gel |
|---|---|---|
| Microbial Count - Persistent Effect | 65 ± 9.4 | 103 ± 8.7 |
Subjects underwent the modified glove juice technique after seeding of hands with S. marcescens bacteria for 1 minute followed by application of one of the two antimicrobial gels; a 1.5 milliliter sample of the juice was collected after 1 minute. The procedure was repeated for each of the two gels, random order assigned.
| CFU/mL | Nano-silver Gel | Alcohol-based Gel |
|---|---|---|
| Microbial Count - Immediate Effect | 101 ± 6.6 | 49 ± 10.2 |
Collected over 48 hours. Non-serious events are listed at a 3% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Nano-silver Gel | — | 0/11 (0%) | 0/11 (0%) |
| Alcohol-based Gel | — | 0/11 (0%) | 0/11 (0%) |
| Age, Categorical(Participants) | Nano-silver Gel | Alcohol-based Gel | Total |
|---|---|---|---|
| <=18 years | 0 | 0 | 0 |
| Between 18 and 65 years | 11 | 11 | 22 |
| >=65 years | 0 | 0 | 0 |
| Sex/Gender, Customized(particpants) | Nano-silver Gel | Alcohol-based Gel | Total |
|---|---|---|---|
| Female | 0 | 0 | 0 |
| Male | 11 | 11 | 22 |
| Region of Enrollment(participants) | Nano-silver Gel | Alcohol-based Gel | Total |
|---|---|---|---|
| United States | 11 | 11 | 22 |
Plan to share: No
No publications or documents are linked to this record.
Ran from Jan 2008 to primary completion in Aug 2008, 7 months.
Results were first posted in Jan 2026, 17 years 5 months after primary completion.
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This study is terminated, as verified in Sep 2025. You cannot join it, but the record below documents what was studied.
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Madigan Army Medical Center