A temperature-sensitive, high-adhesion medical tape: a comparative, single-blind clinical trial

OBJECTIVE

Medical adhesives are used to secure wound care dressings and other critical devices to the skin. While high peel-strength adhesives provide more secure skin attachment, they are difficult to remove from the skin and are correlated with medical adhesive-related skin injuries (MARSI), including skin tears, and an increased risk of infection. Lower-adhesion medical tapes may be applied to avoid MARSI, leading to dressing or device dislodgement and further medical complications.

METHOD

This paper reports on the clinical testing of a new, high-adhesion medical tape, ThermoTape (University of Washington, US), designed for low skin trauma upon release. ThermoTape was benchmarked with Tegaderm (3M, US) and Kind Removal Tape (KRT) (3M, US). All three tapes were applied to both the left and right forearm of healthy volunteers and were removed 24 hours later-the right arm without applying heat and the left arm by applying a heat pack for 30 seconds before removal. Tape wear, self-reported pain (0-10 scale) and skin redness 15 minutes after removal were recorded.

RESULTS

This was a 53-subject comparative, single-blind clinical trial. There were clinically and statistically significant results supporting reduced pain during removal of ThermoTape with warming, with an average 58% decrease in pain, paired with a statistically significant 45% reduction in skin redness (p<0.01 for both values). In contrast, there were statistically insignificant differences in pain and redness for removal of Tegaderm and KRT with warming. ThermoTape after warming, in comparison with Tegaderm without warming, produced a reduced pain score of >1 on the 0-10 Wong-Baker/Face pain scale, which was statistically significant (p<0.01).

CONCLUSION

These results provide compelling evidence that warming ThermoTape prior to removal can reduce pain and injury when compared with standard medical tapes. This could allow for stronger attachment of wound care dressings and critical medical devices while reducing cases of MARSI.

Prototype Development of a Temperature-Sensitive High-Adhesion Medical Tape to Reduce Medical-Adhesive-Related Skin Injury and Improve Quality of Care

Medical adhesives are used to secure wound care dressings and other critical devices to the skin. Without means of safe removal, these stronger adhesives are difficult to painlessly remove from the skin and may cause medical-adhesive-related skin injuries (MARSI), including skin tears and an increased risk of infection. Lower-adhesion medical tapes may be applied to avoid MARSI, leading to device dislodgement and further medical complications. This paper outlines the development of a high-adhesion medical tape designed for low skin trauma upon release. By warming the skin-attached tape for 10-30 s, a significant loss in adhesion was achieved. A C14/C18 copolymer was developed and combined with a selected pressure-sensitive adhesive (PSA) material. The addition of 1% C14/C18 copolymer yielded the largest temperature-responsive drop in surface adhesion. The adhesive film was characterized using AFM, and distinct nanodomains were identified on the exterior surface of the PSA. Our optimized formulation yielded 67% drop in adhesion when warmed to 45 °C, perhaps due to melting nanodomains weakening the adhesive-substrate boundary layer. Pilot clinical testing resulted in a significant decrease in pain when a heat pack was used for removal, giving an average pain reduction of 66%.

O-pH: Optical pH Monitor to Measure Oral Biofilm Acidity and Assist in Enamel Health Monitoring

OBJECTIVE

Bacteria in the oral biofilm produce acid after consumption of carbohydrates which if left unmonitored leads to caries formation. We present O-pH, a device that ca measure oral biofilm acidity and provide quantitative feedback to assist in oral health monitoring.

METHOD

O-pH utilizes a ratiometric pH sensing method by capturing fluorescence of Sodium Fluorescein, an FDA approved chemical dye. The device was calibrated to a lab pH meter using buffered fluorescein solution with a correlation coefficient of 0.97. The calibration was further verified in vitro on additional buffered solution, artificial, and extracted teeth. An in vivo study on 30 pediatric subjects was performed to measure pH before (rest pH) and after a sugar rinse (drop pH), and the resultant difference in pH (diff pH) was calculated. The study enrolled subjects with low (Post-Cleaning) and heavy (Pre-Cleaning) biofilm load, having both unhealthy/healthy surfaces. Further, we modified point-based O-pH to an image-based device using a multimode-scanning fiber endoscope (mm-SFE) and tested in vivo on one subject.

RESULTS AND CONCLUSION

We found significant difference between Post-Cleaning and Pre-Cleaning group using drop pH and diff pH. Additionally, in Pre-Cleaning group, the rest and drop pH is lower at the caries surfaces compared to healthy surfaces. Similar trend was not noticed in the Post-Cleaning group. mm-SFE pH scope recorded image-based pH heatmap of a subject with an average average diff pH of 1.5.

SIGNIFICANCE

This work builds an optical pH prototype and presents a pioneering study for non-invasively measuring pH of oral biofilm clinically.

Optical pH measurement system using a single fluorescent dye for assessing susceptibility to dental caries (Erratum)

The erratum corrects a grant number listed in Acknowledgments section of the original article.

Proof of Concept of a Surrogate High-Adhesion Medical Tape Using Photo-Thermal Release for Rapid and Less Painful Removal

Medical tapes often hold critical devices to the skin so having high adhesion for the lifespan of this product is of great importance. However, the removal process is challenging for caregivers and patients alike, often a painful process that can cause medical adhesive-related skin injury (MARSI). By using an industrial thermally sensitive tape, a surrogate photosensitive tape was developed that switched from the equivalent of high-adhesion medical tape to low-adhesion medical tape. This resulted in an 86% reduction in the average peel strength when heated from 45 to 55 °C using a custom test apparatus. To photo-release the prototype tape (PT), a near-infrared (NIR) absorbing layer was painted on the visibly clear thermal-sensitive tape and an NIR optical wand using 15-LEDs (940 nm) with thermal feedback control was designed and tested. Preliminary performance of photo-to-thermal conversion was numerically modeled with transient results matching experimental measurements with 96.8% correspondence. Using the verified energy conversion model of the surrogate photosensitive tape, a new NIR optical wand was designed for rapid and noncontact release of a future medical tape at 10 deg lower than the release temperature (RTemp) of the custom adhesive, called UnTape. Numerical simulations compared to the thermal skin pain threshold of 45 °C predicts photo-release within 1.1 s of NIR exposure (85.5% absorption in PT at &lt; 1.3 W/cm2). The unique properties of the multifunctional UnTape system (tape and portable NIR wand) may allow even stronger skin adhesion for critical medical devices while concurrently reducing the risk of MARSI upon photo release and easy removal.

Optical pH measurement system using a single fluorescent dye for assessing susceptibility to dental caries

Sugar-rich diets and poor dental hygiene promote the formation of a biofilm (plaque) that strongly adheres to the dental enamel surface and fosters the evolution of aciduric bacteria. The acid contributes to demineralization of the exterior tooth enamel, which accelerates after the pH drops below a critical value (∼5.5) for extended time periods resulting in the need for restorative procedures. Preventative techniques to alert the dentist and caries-susceptible patients regarding vulnerability to dental decay require a clinical measure of plaque activity. Therefore, there is a need to evaluate the acid production capability of plaque deposits in the pits and fissures of occlusal and interproximal regions. A ratiometric fluorescence pH-sensing device has been developed using an FDA-approved dye and LED excitation. Fluorescein spectral profiles were collected using a spectrometer and analyzed with a spectral unmixing algorithm for calibration over the pH range of 4.5 to 7. An in vivo pilot study on human subjects was performed using a sucrose rinse to accelerate bacterial metabolism and to measure the time-dependent drop in pH. The optical system is relatively immune to confounding factors such as photobleaching, dye concentration, and variation in excitation intensity associated with earlier dye-based pH measurement techniques.

Dental pH Opti-Wand (DpOW): measuring oral acidity to guide enamel preservation

Undetected caries can lead to painful cavities and surgical restorations. Lack of proper detection tools makes caries prevention dependent on dentist's expertise and presents obstacles in oral health monitoring. To overcome this problem, we have developed a new approach to predict early stages of enamel demineralization caused by oral bacteria. These bacteria metabolize sugars in our food and produce organic acids that lead to cavities. Measuring the acidity level can help predict early stages of tooth decay. pH paper or pH electrodes can be used to monitor acidity, but neither are able to track pH levels in all dental locations. Our device, DpOW, is a noncontact optics-based pH device that uses changes in the spectral fluorescence of FDA allowed fluorescein dye to measure acidity levels in difficult to access dental locations such as occlusal fissures. A prototype has been tested over a wide pH range (7.12 to 3.89) and shown to track the change in pH with 0.94 correlation coefficient.

Scanning Fiber Endoscope Improves Detection of 5-Aminolevulinic Acid-Induced Protoporphyrin IX Fluorescence at the Boundary of Infiltrative Glioma

OBJECTIVE

Fluorescence-guided surgery with protoporphyrin IX (PpIX) as a photodiagnostic marker is gaining acceptance for resection of malignant gliomas. Current wide-field imaging technologies do not have sufficient sensitivity to detect low PpIX concentrations. We evaluated a scanning fiber endoscope (SFE) for detection of PpIX fluorescence in gliomas and compared it to an operating microscope (OPMI) equipped with a fluorescence module and to a benchtop confocal laser scanning microscope (CLSM).

METHODS

5-Aminolevulinic acid-induced PpIX fluorescence was assessed in GL261-Luc2 cells in vitro and in vivo after implantation in mouse brains, at an invading glioma growth stage, simulating residual tumor. Intraoperative fluorescence of high and low PpIX concentrations in normal brain and tumor regions with SFE, OPMI, CLSM, and histopathology were compared.

RESULTS

SFE imaging of PpIX correlated to CLSM at the cellular level. PpIX accumulated in normal brain cells but significantly less than in glioma cells. SFE was more sensitive to accumulated PpIX in fluorescent brain areas than OPMI (P < 0.01) and dramatically increased imaging time (>6×) before tumor-to-background contrast was diminished because of photobleaching.

CONCLUSIONS

SFE provides new endoscopic capabilities to view PpIX-fluorescing tumor regions at cellular resolution. SFE may allow accurate imaging of 5-aminolevulinic acid labeling of gliomas and other tumor types when current detection techniques have failed to provide reliable visualization. SFE was significantly more sensitive than OPMI to low PpIX concentrations, which is relevant to identifying the leading edge or metastasizing cells of malignant glioma or to treating low-grade gliomas. This new application has the potential to benefit surgical outcomes.

Design and Fabrication of a Disposable Dental Handpiece for Clinical Use of a New Laser-Based Therapy-Monitoring System

Dental caries, the breakdown of tooth enamel by bacteria infection that causes cavities in the enamel, is the most common chronic disease in individuals 6–19 years of age in the U.S. Optical detection of caries has been shown to be sensitive to the presence of bacteria and the resulting demineralization of enamel. The scanning fiber endoscope (SFE) is a miniature camera system that can detect early stages of caries by performing high-quality imaging and laser fluorescence spectroscopy with 405 nm excitation. Because optical imaging of caries does not involve radiation risk, repeated imaging of the teeth is acceptable during treatment of the bacterial infection to monitor healing. A disposable handpiece was designed and fabricated to position the flexible fiber optic SFE probe for quantitative measurements. Plastic 3D-printed handpiece prototypes were tested with the SFE and a fluorescence calibration standard to verify mechanical fit and absence of signal contamination. Design feedback was provided by pediatric dentists and staff engineers to guide iterations. The final design configuration was based on the need to image interproximal regions (contact surfaces between adjacent teeth), ergonomics, and probe safety. The final handpiece design: (1) is safe for both the patient and the probe, (2) allows easy SFE insertion and removal, (3) does not interfere with spectral measurements, (4) standardizes the SFE's positioning during imaging by maintaining a consistent distance from the target surface, and (5) is significantly less expensive to produce and use than purchasing sanitary endoscope sheaths. The device will be used to help determine if new medicinal therapies can arrest caries and repair early interproximal demineralization under the clinical monitoring program. Ultimately, we anticipate that this handpiece will help us move closer toward widespread implementation of a dental diagnostic laser system that is safer and more sensitive than conventional methods for early caries detection.

Target-to-background enhancement in multispectral endoscopy with background autofluorescence mitigation for quantitative molecular imaging

Fluorescence molecular imaging with exogenous probes improves specificity for the detection of diseased tissues by targeting unambiguous molecular signatures. Additionally, increased diagnostic sensitivity is expected with the application of multiple molecular probes. We developed a real-time multispectral fluorescence-reflectance scanning fiber endoscope (SFE) for wide-field molecular imaging of fluorescent dye-labeled molecular probes at nanomolar detection levels. Concurrent multichannel imaging with the wide-field SFE also allows for real-time mitigation of the background autofluorescence (AF) signal, especially when fluorescein, a U.S. Food and Drug Administration approved dye, is used as the target fluorophore. Quantitative tissue AF was measured for the ex vivo porcine esophagus and murine brain tissues across the visible and nearinfrared spectra. AF signals were then transferred to the unit of targeted fluorophore concentration to evaluate the SFE detection sensitivity for sodium fluorescein and cyanine. Next, we demonstrated a real-time AF mitigation algorithm on a tissue phantom, which featured molecular probe targeted cells of high-grade dysplasia on a substrate containing AF species. The target-to-background ratio was enhanced by more than one order of magnitude when applying the real-time AF mitigation algorithm. Furthermore, a quantitative estimate of the fluorescein photodegradation (photobleaching) rate was evaluated and shown to be insignificant under the illumination conditions of SFE. In summary, the multichannel laser-based flexible SFE has demonstrated the capability to provide sufficient detection sensitivity, image contrast, and quantitative target intensity information for detecting small precancerous lesions in vivo.

Trimodal detection of early childhood caries using laser light scanning and fluorescence spectroscopy: clinical prototype

There is currently a need for a safe and effective way to detect and diagnose early stages of childhood caries. A multimodal optical clinical prototype for diagnosing caries demineralization in vivo has been developed. The device can be used to quickly image and screen for any signs of demineralized enamel by obtaining high-resolution and high-contrast surface images using a 405-nm laser as the illumination source, as well as obtaining autofluorescence and bacterial fluorescence images. When a suspicious region of demineralization is located, the device also performs dual laser fluorescence spectroscopy using 405- and 532-nm laser excitation. An autofluorescence ratio of the two excitation lasers is computed and used to quantitatively diagnose enamel health. The device was tested on five patients in vivo as well as on 28 extracted teeth with clinically diagnosed carious lesions. The device was able to provide detailed images that highlighted the lesions identified by the clinicians. The autofluorescence spectroscopic ratios obtained from the extracted teeth successfully quantitatively discriminated between sound and demineralized enamel.

Mitigating fluorescence spectral overlap in wide-field endoscopic imaging

The number of molecular species suitable for multispectral fluorescence imaging is limited due to the overlap of the emission spectra of indicator fluorophores, e.g., dyes and nanoparticles. To remove fluorophore emission cross-talk in wide-field multispectral fluorescence molecular imaging, we evaluate three different solutions: (1) image stitching, (2) concurrent imaging with cross-talk ratio subtraction algorithm, and (3) frame-sequential imaging. A phantom with fluorophore emission cross-talk is fabricated, and a 1.2-mm ultrathin scanning fiber endoscope (SFE) is used to test and compare these approaches. Results show that fluorophore emission cross-talk could be successfully avoided or significantly reduced. Near term, the concurrent imaging method of wide-field multispectral fluorescence SFE is viable for early stage cancer detection and localization in vivo. Furthermore, a means to enhance exogenous fluorescence target-to-background ratio by the reduction of tissue autofluorescence background is demonstrated.

Color-matched and fluorescence-labeled esophagus phantom and its applications

We developed a stable, reproducible three-dimensional optical phantom for the evaluation of a wide-field endoscopic molecular imaging system. This phantom mimicked a human esophagus structure with flexibility to demonstrate body movements. At the same time, realistic visual appearance and diffuse spectral reflectance properties of the tissue were simulated by a color matching methodology. A photostable dye-in-polymer technology was applied to represent biomarker probed "hot-spot" locations. Furthermore, fluorescent target quantification of the phantom was demonstrated using a 1.2 mm ultrathin scanning fiber endoscope with concurrent fluorescence-reflectance imaging.

Spectrally enhanced imaging of occlusal surfaces and artificial shallow enamel erosions with a scanning fiber endoscope

An ultrathin scanning fiber endoscope, originally developed for cancer diagnosis, was used to image dental occlusal surfaces as well as shallow artificially induced enamel erosions from human extracted teeth (n=40). Enhanced image resolution of occlusal surfaces was obtained using a short-wavelength 405-nm illumination laser. In addition, artificial erosions of varying depths were also imaged with 405-, 404-, 532-, and 635-nm illumination lasers. Laser-induced autofluorescence images of the teeth using 405-nm illumination were also obtained. Contrast between sound and eroded enamel was quantitatively computed for each imaging modality. For shallow erosions, the image contrast with respect to sound enamel was greatest for the 405-nm reflected image. It was also determined that the increased contrast was in large part due to volume scattering with a smaller component from surface scattering. Furthermore, images obtained with a shallow penetration depth illumination laser (405 nm) provided the greatest detail of surface enamel topography since the reflected light does not contain contributions from light reflected from greater depths within the enamel tissue. Multilayered Monte Carlo simulations were also performed to confirm the experimental results.

Red-shifted fluorescence of sound dental hard tissue

Autofluorescence spectra were recorded in vitro from dentin, enamel, and whole teeth. The spectra exhibited a broad peak shifted by about 50 to 75 nm from the excitation wavelength and the shape of the spectra remained similar regardless of the excitation wavelength. The maximum of the autofluorescence spectra also exhibited a red-shift that depended upon the laser excitation wavelength. The amplitude of the red-shifted fluorescence spectra produced by 444 and 532 nm excitation lasers were compared to that produced by a 405 nm excitation laser. It was determined that the autofluorescence amplitude was not proportional to the inverse fourth power of the excitation laser wavelength. Therefore, the red-shifted fluorescence is not compatible with the previously proposed mechanism of Raman scattering. Instead, the mechanism giving rise to the laser-induced dental autofluorescence is explained by the red-edge-excitation effect.

Longitudinal-mode control of a CO(2) TE laser by means of intracavity absorbers

Single longitudinal mode output of a pulsed TE CO(2) laser has been obtained using several different intracavity gas-phase absorbers. The method described is simple and inexpensive and appears to be extremely general.