ABSTRACT
Asphalt is used globally in construction for roads, pavements, and buildings; however, as a fossil-derived material, it is known to generate volatile organic compounds (VOCs) upon exposure to heat and light that can be harmful to human health. Several heterogeneous strategies have been reported for the inhibition of these VOCs; however, the direct use of inexpensive, accessible Earth-Abundant metals has not been extensively explored. In this study, simple metal salts are examined for their coordination capability toward asphalt-derived VOCs. From UV-visible (UV-vis) spectroscopic studies, FeCl3 emerged relative to other metal salts (metal = Mn, Co, Ni, Cu, Zn) as a promising candidate for the adsorption and retention of Lewis basic compounds. Coordination of an example oxygen-containing VOC, benzofuran (Bf), to Fe yielded a paramagnetic semi-octahedral complex Fe(Bf)3Cl3. Evaluation by thermal gravimetric analysis (TGA) coupled to infrared spectroscopy (IR) demonstrated that the complex was stable up to 360 °C. Spectroscopic evaluation demonstrated the stability of the complex upon visible light irradiation and in the presence of a variety of organic pollutants. The potential application of Fe was demonstrated by subjecting biochar to FeCl3 followed by the addition of Bf. It was discovered that this Fe-rich biochar was successful at adsorbing Bf suggesting the possibility of introducing Fe to biochar late-stage in processing to deter asphalt degradation and VOC emissions. An understanding of the binding and stability of Fe salts to VOCs provides insight into how a sustainable infrastructure can be achieved.
ABSTRACT
BACKGROUND AND PURPOSE: Mepitel Film (MF) has been demonstrated to reduce the severity of radiation dermatitis (RD) in patients receiving breast cancer radiotherapy (RT). The objective of this study was to characterize patient-reported experience with MF use, including its impact on daily activities and wellbeing. MATERIALS AND METHODS: This single-institution study analyzed anonymized responses to a questionnaire completed by patients who used MF for the prevention of RD during breast cancer RT. RESULTS: Of the 254 patients contacted, 192 patients completed the survey. Most patients disagreed or strongly disagreed that MF limited their ability to perform their daily activities, including household chores (88%, n = 169/191), their ability to work (83%, n = 157/189), or their ability to sleep (85%, n = 163/191). Furthermore, patients agreed or strongly agreed MF was comfortable on their skin (67%, n = 126/189) and protected their skin from rubbing against clothing (86%, n = 161/188). Some patients agreed or strongly agreed that MF affected their ability to shower (31%, n = 50/162), wear bras (28%, n = 51/185), and impacted their level of pruritus (35%, n = 67/189). However, most patients agreed or strongly agreed that their overall experience with MF was positive (92%, n = 173/189) and would recommend MF to a friend undergoing breast cancer RT (88%, n = 166/188). CONCLUSION: MF use is associated with positive patient-reported experience during breast RT with minimal impact on daily activities.
Subject(s)
Breast Neoplasms , Radiodermatitis , Humans , Female , Breast Neoplasms/radiotherapy , Radiodermatitis/prevention & control , Skin , Patient Reported Outcome MeasuresABSTRACT
INTRODUCTION: Malignant spinal cord compression (MSCC) is an oncological emergency that may result in a devastating combination of malignancy and disability. Existing quality of life (QoL) questionnaires commonly used in MSCC literature (EORTC QLQ-C30, BM-22, Brief Pain Inventory, and Spine Oncology Study Group Outcomes) may not capture all the commonly reported symptoms and lack specificity to MSCC. The primary objective of this systematic review is to determine unmet patient needs and underreported QoL issues and compile a comprehensive list of QoL issues. The secondary objective of this review is to compile all existing QoL tools and questionnaires and determine whether any QoL issues are not addressed in the existing tools currently used in the literature. METHODS: A literature search was conducted on Ovid MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases between 1946 and February 6, 2023, to compile all QoL issues and existing questionnaires used to assess QoL in patients with MSCC. All study designs were included given that they discussed QoL issues specific to patients with MSCC. RESULTS: The results of this systematic review identified the most frequently discussed QoL issues in the literature studying MSCC. This included direct symptoms of MSCC such as back pain, paralysis, limb weakness/numbness, and urinary/bowel incontinence. Indirect symptoms coming from radiotherapy treatment such as dysphagia, painful swallowing, mouth pain, dry mouth, diarrhea, fatigue, and nausea/vomiting were also noted. Other symptoms resulting from corticosteroid treatment included difficulty sleeping, blurring of vision, weight gain, and mood disturbance. Patients also experienced psychosocial issues such as anxiety, depression, emotional distress, low self-esteem, concerns about dependence on others, concerns about getting home, and fear about their prognosis and future. CONCLUSION: This review highlights the QoL issues specific to patients with MSCC and QoL tools capturing these issues. Relevance of QoL issues identified in this systematic review must be prospectively validated by patients and healthcare professionals with experience in treating MSCC.
Subject(s)
Quality of Life , Spinal Cord Compression , Humans , Spinal Cord Compression/etiology , Pain , Patients , SpineABSTRACT
PURPOSE: The primary objective is to systematically review primary studies, such as randomized control trials (RCTs), feasibility, exploratory, and case studies; and the secondary objective is to evaluate all secondary articles, such as reviews, guidelines, and editorials, relevant to the use of StrataXRT for the prevention and/or management of radiation dermatitis (RD) in cancer patients. METHODS: A literature search was conducted up to February 26, 2023, for articles investigating the use of StrataXRT for the prevention and treatment of RD, in the following databases: Ovid MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Google Scholar. The keywords "StrataXRT", "dermatitis", "radiotherapy", and "radiation" were used to identify relevant articles. RESULTS: Twenty-seven articles from 2018 to 2022 were identified to fulfill the inclusion criteria of this review, of which nine are primary studies and 18 are secondary papers. Significant heterogeneity was observed in the current literature studying the effects of StrataXRT, making it difficult to make cross-trial comparisons. There is a suggestion of the efficacy of StrataXRT in the prevention and treatment of RD. CONCLUSION: The findings of this review recommend further adequately powered RCTs with robust methodology including patient and clinician assessments to determine the efficacy of StrataXRT in preventing and treating RD. This is essential to improve the quality of life of patients and identify which groups of patients would benefit most from StrataXRT.
Subject(s)
Radiation Oncology , Radiodermatitis , Humans , Quality of Life , Radiodermatitis/etiology , Radiodermatitis/prevention & controlABSTRACT
INTRODUCTION: Randomized clinical trials support Mepitel Film (MF) as a prophylactic treatment for radiation dermatitis (RD) in patients undergoing breast radiotherapy. Although several studies have canvassed the opinion of patients on using MF, no such studies have been done to investigate the perception of healthcare professionals (HCPs). The objective of this study was therefore to investigate the perceptions of HCPs on MF as a treatment option for RD. METHODS: Anonymized responses to a web-based survey sent to HCPs at a single institution managing patients using MF during breast radiotherapy were analyzed. RESULTS: Of the 28 HCPs contacted, 22 completed the survey, including 6 radiation oncologists (ROs), 11 radiation therapists (RTTs), and 5 nurses. Most HCPs reported MF was better at preventing severe RD than the standard of care and improved radiation-induced skin reactions (n = 20/22, 91%, and n = 19/22, 86%, respectively). MF was recommended for mastectomy patients without reconstruction (n = 15/21, 71%). The majority of HCPs believed that patients' families could be trained to apply and remove MF (n = 19/22, 86%). Many HCPs perceived that implementation of MF would be difficult in terms of maintaining patient flow and wide-scale implementation within their institution (n = 11/22, 50%, and n = 10/22, 46%, respectively). Most HCPs perceived that fewer than 50% of their patients could afford MF if priced at $100 CAD (n = 15/20, 75%). CONCLUSION: These findings provide insights into the possibility of MF to be incorporated into standard practice of care for RD. Although most HCPs were satisfied with MF as a prophylactic treatment for RD, there are concerns about its resource-intensive operationalization and financial accessibility to patients. Future research should focus on ways to improve HCP experience with MF and to improve its implementation into clinical settings as standard of care.
Subject(s)
Breast Neoplasms , Radiodermatitis , Humans , Female , Breast Neoplasms/radiotherapy , Mastectomy , Health Personnel , Radiodermatitis/prevention & control , Delivery of Health CareABSTRACT
PURPOSE: This systematic review and meta-analysis aimed to evaluate the efficacy of Mepitel film in preventing or treating acute radiation dermatitis (RD) in patients with breast cancer in randomized controlled trials (RCTs). METHODS: Embase, APA PsychInfo, Journals@Ovid Full Text, Ovid MEDLINE, PubMed, and Cochrane Trials were searched until December 12, 2022, to identify RCTs on the use of Mepitel film for preventing or treating acute RD from breast cancer radiotherapy. Per-protocol analysis was used to compare outcomes, calculate pooled effect sizes, odds ratio (OR), and 95% confidence intervals (CI), and to create forest plots using random effects analysis in RevMan 5.4. RESULTS: Three RCTs were included in this review. Mepitel film significantly reduced the incidence of grade 3 RD (OR 0.15 95% CI 0.06, 0.37, p<0.0001) and grade 2 or 3 RD (OR 0.16 95% CI 0.04, 0.65, p=0.01) as scored on either the CTCAE or the RTOG scale. Additionally, Mepitel film significantly reduced RISRAS mean scores assessed by patients and combined researcher and patient (standardized mean difference (SMD) -7.59, 95% CI -14.42, -0.76, p=0.03; SMD -15.36, 95% CI -30.01, -0.71 p=0.04) but not the researcher component of the assessment tool (SMD -17.55, 95% CI -36.94, 1.84, p=0.08). CONCLUSION: Mepitel film reduced the incidence of acute RD and improved patient-reported outcomes with minimal side effects, the main one being itchiness. Future research should assess the feasibility of Mepitel film with respect to specific patient-reported outcomes such as health-related quality of life issues associated with its use.
Subject(s)
Breast Neoplasms , Radiodermatitis , Humans , Female , Randomized Controlled Trials as Topic , Breast Neoplasms/radiotherapy , Breast Neoplasms/complications , Silicones , Radiodermatitis/prevention & control , Radiodermatitis/etiologyABSTRACT
PURPOSE: This systematic review and meta-analysis evaluates the efficacy of Mepitel Film in preventing acute radiation dermatitis (RD) in patients with head and neck cancer (HNC) across randomized controlled trials (RCTs). METHODS: Embase, MEDLINE, and Cochrane Central Register of Controlled Trials were searched on 5 March 2023 to identify relevant RCTs. RD assessment tools and outcomes were compared across studies. Pooled effect sizes and 95% confidence intervals (CI) were estimated based on random-effects analysis using RevMan 5.4. RESULTS: Three RCTs conducted between 2018 and 2020 were included. Mepitel Film decreased RD severity when compared to Sorbolene or Biafine but not when compared to mometasone. A per-protocol analysis of two of the trials revealed that, overall, Mepitel Film significantly reduced the incidence of grade 2-3 RD (odds ratio (OR), 0.24; 95% CI, 0.09-0.65; p = 0.005) and moist desquamation (OR, 0.21; 95% CI, 0.10-0.46; p < 0.0001) and decreased average patient, researcher, and combined components of the Radiation-Induced Skin Reaction Assessment Scale (the standardized mean difference (SMD) for patient ratings, - 2.56; 95% CI, - 3.15 to - 1.96, p < 0.00001; SMD for researcher ratings, - 3.47; 95% CI, - 6.63 to - 0.31, p = 0.03; SMD for combined scores, - 3.68; 95% CI, - 6.43 to - 0.92, p = 0.009). Noted issues with Mepitel Film included itchiness and poor adherence. CONCLUSION: While there were discrepancies across studies, Mepitel Film demonstrated a decrease in the incidence of grade 2-3 RD and moist desquamation. These findings emphasize the need for further examining Mepitel Film's efficacy across diverse patient groups and the importance of standardizing RD severity assessment methodologies and control arms.
Subject(s)
Dermatitis , Head and Neck Neoplasms , Humans , Randomized Controlled Trials as Topic , Head and Neck Neoplasms/radiotherapy , Motion PicturesABSTRACT
PURPOSE: To evaluate the overall efficacy of StrataXRT, a topical gel dressing, in preventing acute radiation dermatitis (RD) in breast cancer patients undergoing radiotherapy (RT). METHODS: A systematic search was conducted on April 25, 2023 in Ovid MEDLINE, Embase, and Cochrane Central Register of Controlled Trials. Randomized controlled trials (RCTs) assessing the effectiveness of StrataXRT in preventing acute RD in breast cancer patients undergoing adjuvant RT to the breast or chest wall with or without regional nodes were included. Pooled incidence odds ratio (OR) and 95% confidence interval (CI) were calculated using a random-effects model, with analysis and forest plots generated in RevMan v5.4. RESULTS: The analysis included three RCTs with a total of 189 patients assessed using per-protocol analysis. Two RCTs compared StrataXRT to standard of care, while the third compared it with Mepitel film and was reported separately. In the former RCTs, the odds ratio (OR) for developing acute grade 3 RD favored StrataXRT at 0.05 (95% CI, 0.01-0.22; P < 0.0001). The OR for developing acute grades 2-3 RD was 0.32 (95% CI, 0.03-3.18; P = 0.33). The RCT comparing StrataXRT with Mepitel film showed insignificant ORs for grade 3 and grades 2-3 RD. One RCT reported significantly lower erythema index (P = 0.008) and melanin index (P = 0.015) in StrataXRT patients. The use of StrataXRT did not raise additional safety concerns. CONCLUSION: StrataXRT may help prevent severe acute RD in breast cancer RT patients. Further high quality, large-scale studies are needed to confirm these findings.
Subject(s)
Breast Neoplasms , Radiodermatitis , Humans , Female , Randomized Controlled Trials as Topic , Breast Neoplasms/radiotherapy , Silicones , Radiodermatitis/prevention & controlABSTRACT
BACKGROUND AND PURPOSE: Regional nodal irradiation (RNI) is commonly administered in patients with breast cancer with node-positive disease to prevent cancer recurrence. The purpose of this study is to identify whether RNI is associated with greater acute symptom burden from baseline to 1 to 3 months post completion of radiotherapy (RT) when compared to localized RT. MATERIALS AND METHODS: Patient and treatment characteristics were collected prospectively for breast cancer patients with and without RNI from February 2018 to September 2020. The Edmonton Symptom Assessment System (ESAS) and Patient-Reported Functional Status (PRFS) tool were completed by patients at baseline, weekly during RT, and at a 1- to 3-month follow-up visit. The Wilcoxon rank-sum or Fisher exact tests were used to compare variables between patients with or without RNI. RESULTS: A total of 781 patients were included in the analysis. Baseline symptom reporting was similar between cohorts, with the exception of PRFS scores (p = 0.0023), which were worse in patients receiving RNI. Across all time points, differences in outcomes between cohorts were minimal, except for lack of appetite (p = 0.03) and PRFS scores (p = 0.049), which were significantly aggravated in patients treated with RNI. CONCLUSION: There is insufficient evidence to suggest that RNI is associated with greater symptom burden as assessed with the ESAS. Further research should be conducted over a longer time period to determine the impact of late effects of RNI on patient-reported symptoms.
Subject(s)
Breast Neoplasms , Humans , Female , Breast Neoplasms/radiotherapy , Neoplasm Recurrence, Local , Patient Reported Outcome MeasuresABSTRACT
BACKGROUND AND PURPOSE: Patients undergoing radiotherapy (RT) for breast cancer may receive adjuvant or neoadjuvant chemotherapy prior to the initiation of RT treatment. In the present study, baseline Edmonton Symptom Assessment System (ESAS) scores of patients who received neoadjuvant and adjuvant chemotherapy were collected prior to RT and compared to assess the association of each chemotherapy intent with pre-RT symptom burden. MATERIAL AND METHODS: The ESAS and Patient-Reported Functional Status (PRFS) tools were used to collect patient-reported symptoms at baseline. Patient and treatment-related factors were collected prospectively from February 2018 to September 2020. Univariate general linear regression analysis was applied to compare baseline scores between adjuvant and neoadjuvant chemotherapy patients. RESULTS: A total of 338 patients were included for analysis. Comparison of baseline ESAS scores revealed that patients who received adjuvant chemotherapy were more likely to report higher scores, reflecting higher symptom burden, compared to patients receiving neoadjuvant chemotherapy, including tiredness (p = 0.005), lack of appetite (p = 0.0005), shortness of breath (p < 0.0001), and PRFS (p = 0.012). CONCLUSION: This study suggests an association between patients who have received adjuvant chemotherapy for breast cancer and higher RT baseline ESAS scores when compared to patients who received neoadjuvant chemotherapy. Due to these findings, considerations should be made by healthcare providers of the symptom burden during RT for patients who receive adjuvant chemotherapy.
Subject(s)
Breast Neoplasms , Radiation Oncology , Humans , Female , Breast Neoplasms/drug therapy , Breast Neoplasms/diagnosis , Neoadjuvant Therapy , Symptom Assessment , Chemotherapy, AdjuvantABSTRACT
BACKGROUND AND PURPOSE: As breast cancer radiotherapy (RT) has been shown to give rise to adverse pulmonary outcomes, such as radiation pneumonitis, trends in patient-reported shortness of breath (SOB) associated with RT were investigated. Adjuvant RT is commonly administered for local and/or regional control of breast cancer and was therefore included. METHODS: The Edmonton Symptom Assessment System (ESAS) was used to observe changes in SOB during RT, up to 6 weeks after RT completion, and one to three months post-RT. Patients with at least one completed ESAS were included in the analysis. Generalized linear regression analysis was performed to identify associations between demographic factors and SOB. RESULTS: A total of 781 patients were included in the analysis. There was a significant association between ESAS SOB scores and adjuvant chemotherapy when compared to neoadjuvant chemotherapy (p=0.0012). Meanwhile, loco-regional RT had no significant impact on ESAS SOB scores in comparison to local RT. SOB scores were stable over time (p>0.05) from baseline to follow-up appointments. CONCLUSION: The findings of this study suggest that RT was not associated with changes in SOB from baseline to 3 months post-RT. However, patients who underwent adjuvant chemotherapy reported significant higher SOB scores over time. Additional research is recommended to analyze the lasting effects of adjuvant breast cancer RT on SOB during physical activity.
Subject(s)
Breast Neoplasms , Humans , Female , Breast Neoplasms/radiotherapy , Breast Neoplasms/diagnosis , Radiotherapy, Adjuvant , Breast , Dyspnea/etiology , Patient Reported Outcome MeasuresABSTRACT
PURPOSE: Radiation dermatitis (RD) is common in patients undergoing breast radiotherapy. Mepitel film (MF) can reduce RD, but the results from two randomized controlled trials are conflicting. We aimed to conduct a confirmatory randomized controlled trial in patients at risk of RD. METHODS: Patients were randomly assigned to receive MF or standard care (2:1 ratio). Patients with large breasts after lumpectomy (bra size ≥ 36 inches or cup size ≥ C) or after mastectomy were eligible. Stratification factors included surgery type, dose fractionation, and administration of boost/bolus. The primary end point was grade (G) 2 or 3 RD using the Common Terminology Criteria for Adverse Events v5.0. Secondary end points included patient- and clinician-reported outcomes. RESULTS: Between January 2020 and May 2022, 376 patients were included in the modified intention-to-treat analysis. The incidence of G2 or 3 RD was significantly lower in MF patients compared with standard care (n = 39/251, 15.5%; 95% CI, 11.3 to 20.6% v n = 57/125, 45.6%; 95% CI, 36.7 to 54.8% respectively, odds ratio (OR): 0.20, P < .0001). Benefits of MF remained significant in patients who developed G 3 RD (n = 7, 2.8%; 95% CI, 1.1 to 5.7% v n = 17, 13.6%; 95% CI, 8.1 to 20.9%, OR: 0.19) and moist desquamation (n = 20, 8.0%; 95% CI, 4.9 to 12.0% v n = 24, 19.2%; 95% CI, 12.7 to 27.1%, OR: 0.36). When evaluating the combined patient and health care provider score using Radiation-Induced Skin Reaction Assessment Scale, the MF arm had significantly lower scores (P < .0001). Individual items on the Radiation-Induced Skin Reaction Assessment Scale also favored the MF for both patient- and clinician-reported outcomes. Blistering/peeling, erythema, pigmentation, and edema were significantly reduced in the MF arm. Three patients removed the film prematurely because of rash (n = 2) and excessive pruritus (n = 1). CONCLUSION: MF significantly reduces RD in patients undergoing breast radiotherapy.
Subject(s)
Breast Neoplasms , Radiodermatitis , Humans , Female , Breast Neoplasms/radiotherapy , Breast Neoplasms/surgery , Breast Neoplasms/complications , Mastectomy/adverse effects , Radiodermatitis/etiology , Radiodermatitis/prevention & control , Silicones , Randomized Controlled Trials as TopicABSTRACT
This research demonstrates the development, application, and mechanistic value of a multi-detector asymmetric flow field-flow fractionation (AF4) approach to acquire size-resolved drug loading and release profiles from polymeric nanoparticles (NPs). AF4 was hyphenated with multiple online detectors, including dynamic and multi-angle light scattering for NP size and shape factor analysis, fluorescence for drug detection, and total organic carbon (TOC) to quantify the NPs and dissolved polymer in nanoformulations. The method was demonstrated on poly(lactic-co-glycolic acid) (PLGA) NPs loaded with coumarin 6 (C6) as a lipophilic drug surrogate. The bulk C6 release profile using AF4 was validated against conventional analysis of drug extracted from the NPs and complemented with high performance liquid chromatography - quadrupole time-of-flight (HPLC-QTOF) mass spectrometry analysis of oligomeric PLGA species. Interpretation of the bulk drug release profile was ambiguous, with several release models yielding reasonable fits. In contrast, the size-resolved release profiles from AF4 provided critical information to confidently establish the release mechanism. Specifically, the C6-loaded NPs exhibited size-independent release rate constants and no significant NP size or shape transformations, suggesting surface desorption rather than diffusion through the PLGA matrix or erosion. This conclusion was supported through comparative experimental evaluation of PLGA NPs carrying a fully entrapped drug, enrofloxacin, which showed size-dependent diffusive release, along with density functional theory (DFT) calculations indicating a higher adsorption affinity of C6 onto PLGA. In summary, the development of the size-resolved AF4 method and data analysis framework fulfills salient analytical gaps to determine drug localization and release mechanisms from nanomedicines.
Subject(s)
Nanoparticles , Polyglycolic Acid , Polyglycolic Acid/chemistry , Polylactic Acid-Polyglycolic Acid Copolymer , Lactic Acid/chemistry , Drug Liberation , Particle Size , Nanoparticles/chemistry , Drug Carriers/chemistryABSTRACT
Asphalt-surfaced areas such as roads have been reported as major non-combustion sources of reactive organic compounds in urban areas. Emission of latter compounds from asphalt is exacerbated due to exposure to sunlight and high temperature, contributing to negative human and environmental health outcomes. Furthermore, loss of asphalt components over time is linked to bitumen's aging that reduces service life of roads. Here, we introduce a designed bio-grafted-silica nano-filler derived from wood pellet as a sink for latter volatile compounds in an asphalt mixture. Molecular modeling calculations showed the remarkable adsorptive activity of the bio-grafted silica for trapping select asphalt volatiles, especially for the sulfur-containing aromatics and the oxygen-containing aromatics. Laboratory experiment revealed that the bitumen modified with bio-grafted silica exhibited up to 23% lower signs of aging. Thermogravimetric analysis proved that the modified bitumen exhibited a 16% reduction in mass loss compared to neat bitumen. Dynamic vapor sorption analysis also showed bio-grafted silica adsorbed higher amounts of a candidate volatile than pristine silica. The study outcomes highlights the advantages of a bio-derived modifier in asphalt to address concerns associated with the loss of hazardous compounds.
Subject(s)
Environmental Pollutants , Silicon Dioxide , Humans , Hydrocarbons , Oxygen , SulfurABSTRACT
It has been reported that adding polyphosphoric acid (PPA) to bitumen modified with Montmorillonite clay (MMT) makes the bituminous composite less prone to swelling and more resistant to moisture damage, thus improving two major causes of pavement distress. There has been no in-depth study on the underlying mechanism for such a synergistic effect between MMT and PPA. Here, we used laboratory experiments and computational modeling to study how PPA moderates the intermolecular interactions in bitumen modified with MMT. The results showed that PPA had notable interactions with both MMT and bitumen components (BCs); however, PPA's preferential adsorption to MMT was verified by a significantly higher binding energy (-127.3 kcal/mol) for PPA-sealed MMT than for PPA-BCs (-85.9 kcal/mol). The higher binding energy for PPA-sealed MMT caused PPA to be strongly adsorbed on the MMT surface in the first stage, causing partial intercalation into the clay gallery and blocking subsequent entry of water. PPA's affinity to interact with BCs then allowed PPA to be a bridge between MMT and BCs, leading to more intermolecular interactions and better sealing for MMT. The calculated binding energies for interactions of BC with pre-adsorbed PPA on MMT were higher than those for interactions of BC with PPA alone. In both dry and wet laboratory conditions, bitumen modified with PPA-sealed MMT had higher values of shear thinning and G*/sin(δ) than bitumen modified with MMT.