Consultation Pricing of the Online Health Care Service in China: Hierarchical Linear Regression Approach.

BACKGROUND: Online health care services are a possible solution to alleviate the lack of medical resources in rural areas, and further understanding of the related medical service pricing system would contribute to improvement of the online health care community (OHC). Although many studies have investigated the OHC, the impact of physicians' reputations and wage levels on consulting prices in the OHC has rarely been discussed in the literature. OBJECTIVE: This study was designed to explore the determinants of consulting prices in the OHC. We addressed the following questions: (1) Are the prices of online health consultation services affected by wage levels at the doctor's location? (2) How does a physician's online and offline reputation affect their consulting prices? METHODS: Employing a large-scale sample of 16,008 doctors in China, we first used descriptive statistics to investigate the determinants of consulting prices in their entirety. Hierarchical linear modeling was then used to investigate the determinants of consulting prices in the OHC. RESULTS: The empirical results led to the conclusion that if doctors have more elevated clinic titles, work in higher-level hospitals, have better online reputations, and/or have made more past sales, their consulting prices will be higher. Additionally, the wage level in the city in which the doctor is working determines their opportunity cost and therefore also affects consulting prices. CONCLUSIONS: The findings indicate that the characteristics of the doctor, the doctor's online reputation, and past sales affect the consulting price. In particular, the wage level in the city affects the price of the consultation. These findings highlight that the OHC is important because it can indeed break through geographical restrictions and give rural residents the opportunity to obtain medical service from doctors in big cities. However, doctors from cities often charge higher fees because of their higher opportunity cost. The results reveal that one of the most important functions of the OHC is to reduce the medical disparity between urban and rural areas; however, planners appear to ignore the possibility that rural residents with lower incomes may not be able to afford such high medical consultation costs. Therefore, the government should consider providing incentives to encourage urban doctors to provide discounts to rural residents or directly offer appropriate subsidies.

Exploring Types of Information Sources Used When Choosing Doctors: Observational Study in an Online Health Care Community.

BACKGROUND: Patients attempt to make appropriate decisions based on their own knowledge when choosing a doctor. In this process, the first question usually faced is that of how to obtain useful and relevant information. This study investigated the types of information sources that are used widely by patients in choosing a doctor and identified ways in which the preferred sources differ in various situations. OBJECTIVE: This study aims to address the following questions: (1) What is the proportion in which each of the various information sources is used? (2) How does the information source preferred by patients in choosing a doctor change when there is a difference in the difficulty of medical decision making, in the level of the hospital, or in a rural versus urban situation? (3) How do information sources used by patients differ when they choose doctors with different specialties? METHODS: This study overcomes a major limitation in the use of the survey technique by employing data from the Good Doctor website, which is now China's leading online health care community, data which are objective and can be obtained relatively easily and frequently. Multinomial logistic regression models were applied to examine whether the proportion of use of these information sources changes in different situations. We then used visual analysis to explore the question of which type of information source patients prefer to use when they seek medical assistance from doctors with different specialties. RESULTS: The 3 main information sources were online reviews (OR), family and friend recommendations (FR), and doctor recommendations (DR), with proportions of use of 32.93% (559,345/1,698,666), 23.68% (402,322/1,698,666), and 17.48% (296,912/1,698,666), respectively. Difficulty in medical decision making, the hospital level, and rural-urban differences were significantly associated with patients' preferred information sources for choosing doctors. Further, the sources of information that patients prefer to use were found to vary when they looked for doctors with different medical specialties. CONCLUSIONS: Patients are less likely to use online reviews when medical decisions are more difficult or when the provider is not a tertiary hospital, the former situation leading to a greater use of online reviews and the latter to a greater use of family and friend recommendations. In addition, patients in large cities are more likely to use information from online reviews than family and friend recommendations. Among different medical specialties, for those in which personal privacy is a concern, online reviews are the most common source. For those related to children, patients are more likely to refer to family and friend recommendations, and for those related to surgery, they value doctor recommendations more highly. Our results can not only contribute to aiding government efforts to further promote the dissemination of health care information but may also help health care industry managers develop better marketing strategies.

Causal Effect of Honorary Titles on Physicians' Service Volumes in Online Health Communities: Retrospective Study.

BACKGROUND: An OHC online health community (OHC) is an interactive platform for virtual communication between patients and physicians. Patients can typically search, seek, and share their experience and rate physicians, who may be involved in giving advice. Some OHC providers provide incentives in form of honorary titles to encourage the web-based involvement of physicians, but it is unclear whether the award of honorary titles has an impact on their consultation volume in an OHC. OBJECTIVE: This study is designed to identify the differential treatment effect of the incentive policy on the service volumes for the subgroups of treatment and control in an OHC. This study aims to answer the following questions: Does an honorary title for physicians impact their service volumes in an OHC? During the period of discontinuity, can we identify the sharp effect of the incentive award on the outcomes of physicians' service volumes? METHODS: We acquired the targeted samples based on treatment, namely, physicians with an honorary title or not and outcomes measured before and after the award of the 2 subgroups. A regression discontinuity design was applied to investigate the impact of the honorary titles incentive as a treatment in an OHC. There was a sharply discontinuous effect of treatment on physicians' online health service performance. The experimental data set consisted of 346 physicians in the treatment group (with honorary titles). Applying the propensity score matching method, the same size of physicians (n=346) was matched and selected as the control group. RESULTS: A sharp discontinuity was found at the time of the physician receiving the honorary title. The results showed that the parametric estimates of the coefficient were significantly positively (P<.001) associated with monthly home page views. The jump in the monthly volumes of home page views was much sharper than that of the monthly consultations. CONCLUSIONS: The changes in the volumes of monthly consultations and home page views reflect the differential treatment effect of honorary titles on physicians' service volumes. The effect of the incentive policy with honorary titles is objectively estimated from both the perspective of online and offline medical services in an OHC. Being named with honorary titles significantly multiplied monthly home page views, yet it did not significantly impact monthly consultations. This may be because consultation capacity is limited by the physician's schedule for consultations.

Understanding a Nonlinear Causal Relationship Between Rewards and Physicians' Contributions in Online Health Care Communities: Longitudinal Study.

BACKGROUND: The online health care community is not just a place for the public to share physician reviews or medical knowledge, but also a physician-patient communication platform. The medical resources of developing countries are relatively inadequate, and the online health care community is a potential solution to alleviate the phenomenon of long hospital queues and the lack of medical resources in rural areas. However, the success of the online health care community depends on online contributions by physicians. OBJECTIVE: The aim of this study is to examine the effect of incentive mechanisms on physician's online contribution behavior in the online health community. We addressed the following questions: (1) from which specialty area are physicians more likely to participate in online health care community activities, (2) what are the factors affecting physician online contributions, and (3) do incentive mechanisms, including psychological and material rewards, result in differences of physician online contributions? METHODS: We designed a longitudinal study involving a data sample in three waves. All data were collected from the Good Doctor website, which is the largest online health care community in China. We first used descriptive statistics to investigate the physician online contribution behavior in its entirety. Then multiple linear and quadratic regression models were applied to verify the causal relationship between rewards and physician online contribution. RESULTS: Our sample included 40,300 physicians from 3607 different hospitals, 10 different major specialty areas, and 31 different provinces or municipalities. Based on the multiple quadratic regression model, we found that the coefficients of the control variables, past physician online contributions, doctor review rating, clinic title, hospital level, and city level, were .415, .189, -.099, -.106, and -.143, respectively. For the psychological (or material) rewards, the standardized coefficient of the main effect was 0.261 (or 0.688) and the standardized coefficient of the quadratic effect was -0.015 (or -0.049). All estimates were statistically significant (P<.001). CONCLUSIONS: Physicians with more past physician online contribution, with higher review ratings, coming from lower level clinics, not coming from tertiary hospitals, and not coming from big cities were more willing to participate in online health care community activities. To promote physician online contribution, it is necessary to establish an appropriate incentive mechanism including psychological and material rewards. Finally, our findings suggest two guidelines for designing a useful incentive mechanism to facilitate physician online contribution. First, material reward is more useful than psychological reward. Second, as indicated by the concave-down-increasing causal relationship between rewards and physician online contribution, although an appropriate reward is effective in encouraging willingness on the part of physicians to contribute to the online health care community, the effect of additional rewards is limited.

Deficiency of the microRNA-31-microRNA-720 pathway in the plasma and endothelial progenitor cells from patients with coronary artery disease.

OBJECTIVE: Defects in angiogenesis/vasculogenesis or vessel repair are major complications of coronary artery disease (CAD). Endothelial progenitor cells (EPCs) play a fundamental role in postnatal vascular repair and CAD. The role of microRNAs in CAD pathogenesis and their potential as biomarkers remain to be elucidated. APPROACH AND RESULTS: MicroRNA-31 (miR-31) level in both the plasma and EPCs of patients with CAD is found lower. miR-31 regulates EPC activities by targeting FAT atypical cadherin 4 and thromboxane A2 receptor, which show increased expression in CAD EPCs. Overexpressing miR-31 in CAD EPCs rescued their angiogenic and vasculogenic abilities both in vitro and in vivo. When exploring approaches to restore endogenous miR-31, we found that far-infrared treatment enhanced the expression of not only miR-31, but also miR-720 in CAD EPCs. miR-720, which was also decreased in EPCs and the plasma of patients with CAD, stimulated EPC activity by targeting vasohibin 1. The miR720-vasohibin 1 pair was shown to be downstream of FAT atypical cadherin 4, but not of thromboxane A2 receptor. FAT atypical cadherin 4 inhibited miR-720 expression via repression of the planar cell polarity signaling gene four-jointed box 1 (FJX1), which was required for miR-720 expression through a hypoxia-inducible factor 1, α subunit-dependent mechanism. Restoring miR-720 level strengthened activity of CAD EPCs. The miR-31-miR-720 pathway is shown critical to EPC activation and that downregulation of this pathway contributes to CAD pathogenesis. Circulating levels of miR-31, miR-720, and vasohibin 1 have the potential to allow early diagnosis of CAD and to act as prognosis biomarkers for CAD and other EPC-related diseases. CONCLUSIONS: Manipulating the expression of the miR-31-miR-720 pathway in malfunction EPCs should help develop novel therapeutic modalities.

The association between leisure activity and mental health in the older adults in China: amazing Guangchangwu.

Objective: Since the mental health of older adult is an important topic in the aging society, the main purpose of this study is to understand the mental health status of the older adult in China under different conditions. More importantly, although people generally believe that leisure activities can improve mental health, the impact of these activities on older adult has not yet been fully discussed. Hence, this study further explores that what kind of leisure activity is associated with mental health of the older adult given different conditions. Methods: We conducted a cross-sectional questionnaire survey to explore the relationships of various leisure activities on mental health among older adults under different demographics. This study used the Geriatric Depression Scale short forms scale (GDS-15) to assess the mental health of older adults. Based on a sample of 2,006 participants, both two-sample t-test and ANOVA were adopted to analyze the characteristics of mental health among specific subsamples. Results: Our findings indicated that older adults generally have higher mental health scores if they do not have chronic diseases, live with other family members, or reside in urban. First, three leisure activities including walking, Guangchangwu, and hiking have positive associations on mental health for older adults with chronic diseases. Second, the older adults living alone engaged in Guangchangwu or hiking significantly associated with their good mental health. Finally, only Guangchangwu has a significantly positive associated with the mental health of rural older adults. Conclusions: Based on our results, the government and healthcare planners can better allocate limited resources under different conditions to promote certain leisure activities, which are helpful to enhance the mental health of older adults. Guangchangwu is an activity that meets the characteristics of Chinese culture, so we further conclude that it is significantly associated with the good mental health of older adults in China.

Electronic consultation accessibility influence on patient assessments: A case-control study with user-generated tags of physician expertise.

Objective: In online health communities (OHCs), patients often list their physicians' expertise by user-generated tags based on their consulted diseases. These expertise tags play an essential role in recommending the match of physicians to future patients. However, few studies have examined the impact of the accessibility of e-consults on patient assessments using marking of the physicians' expertise in OHCs. This study aims to investigate what are the patient assessments of the physicians' expertise if they have e-consult accessibility. Methods: Through a case-control study, this article examined the effect of e-consult accessibility on patient-generated tags of physician expertise in OHCs. With data collected from the Good Doctor website, the samples consisted of 9841 physicians from 1255 different hospitals widely distributed in China. The breadth of voted expertise (BE) is measured by the number of consulted disease-related labels marked by a physician's served patients (SP). The volume of votes (VV) is measured by the number of a physician's votes given by the SP. The degree of voted diversity (DD) is measured by the information entropy of each physician's service expertise (labeled and voted by patients). The data analysis of e-consult accessibility is conducted by estimating the average treatment effect on the DD of physicians' expertise. Results: For the BE, its mean was 7.305 for the case group of physicians with e-consults accessible (photo and text queries), while the mean was 9.465 for the control for physicians without e-consults. For the VV, its mean was 39.720 for the case group, while the mean was 84.565 for the control. For the DD, its mean on patient-generated tags was 2.103 for the case group, which is 0.413 lower than the control group. Conclusion: The availability of e-consults increases the concentration on physician expertise in the patient-generated tags. e-Consults reinforce the increment of the already-received physician expertise (reflected in tags), reducing the tag information diversity.

Understanding the Inequality of Web Traffic and Engagement in Online Healthcare Communities.

The online healthcare community (OHC) is a kind of doctor-patient communication platform, in which doctors can share medical knowledge and provide various kinds of counsel for patients. However, if the OHC's web traffic is concentrated on a small number of doctors, or if only a few doctors are actively involved in the OHC's activities, this will not be conducive to the optimal development of the OHC. This study explores this issue of inequality and makes three main innovations. First, based on data on web traffic and engagement extracted from 139,037 doctors' web pages in one popular OHC, we point out how serious the inequality phenomenon is. Second, we confirm that the Matthew effect indeed exists in this context and leads to greater inequality. Third, we demonstrate that the inequality of psychological or material rewards causes the inequality of web traffic or engagement to become worse; hence, an appropriate reward mechanism should be designed to mitigate the Matthew effect rather than enhance it. Finally, we discuss the managerial implications of these results, as well as avenues for future studies.

Do Critical Reviews Affect Box Office Revenues Through Community Engagement and User Reviews?

With advances in technology and the popularity of the Internet, consumers increasingly rely on various sources of electronic word-of-mouth (eWOM), such as online user reviews and critical reviews, in their decision-making processes. Despite general consensus on the importance of eWOM and the ability of critical reviews to influence product sales, very little is known about the mediation between critical reviews and user reviews. Therefore, we used path analysis to examine how critical reviews and user reviews simultaneously affect box office revenues using eWOM data collected from Metacritic.com and IMDb.com, and box office revenue information collected from BoxOfficeMojo.com. The results showed that critical reviews valence not only directly affects box office revenues but also increases active postings in the community and user reviews volume, thus indirectly leading to greater box office revenues. The study provides strategic guidance and practical implications for eWOM communication management.

Can online health information sources really improve patient satisfaction?

Internet information has become the main way for individuals to obtain health information. The purpose of this paper is to explore the role online information sources play in health decision-making. Specifically, we investigated the relationship between online information sources and patient satisfaction, as well as their moderating effects as compared to those of other information sources. Using logistical regression analysis, we conducted the longitudinal data on 54,027 doctors and 952,877 online doctor reviews from 3,525 hospitals in 31 provinces to test a proposed research model. The results showed that patient satisfaction was generally lower for individuals who found a doctor through online information sources. Therefore, we suggest that patients consider the doctor quality, the doctor popularity, and patient involvement. In addition, we found that the doctor popularity had a negative moderating effect between online information sources and patient satisfaction, while patient involvement had a positive moderating effect between online information sources and patient satisfaction. The study provides strategic guidance and practical implications for policies, online healthcare community managers, and patients.

Impacts of physician promotion on the online healthcare community: Using a difference-in-difference approach.

In this study, we use a difference-in-difference approach to explore how physician promotion, the advancement of a physician's offline reputation, affects patient behavior toward physicians in online healthcare communities; this allows us to explore how patients interpret the signals created by physician promotion. The study sample was collected from over 140,000 physician online profiles after 25 months of continuous observation, with 280 physicians who were promoted at month 13 as the treatment group and a control group obtained by propensity score matching. Our results show that a physician's promotion causes more patients to choose that physician, makes patients willing to give more psychological rewards, and makes them tend to give that physician a higher online rating. This implies that patient behavior is susceptible to the signal of physician promotion because the quality of the physician is unlikely to have changed significantly in the short term. These findings extend prior research on reputation in online communities and have crucial implications for theory and practice.

Identification of the Differential Effect of City-Level on the Gini Coefficient of Health Service Delivery in Online Health Community.

Inequality of health services for different specialty categories not only occurs in different areas in the world, but also happens in the online service platform. In the online health community (OHC), health services often display inequality for different specialty categories, including both online views and medical consultations for offline registered services. Moreover, how the city-level factors impact the inequality of health services in OHC is still unknown. We designed a causal inference study with data on distributions of serviced patients and online views in over 100 distinct specialty categories on one of the largest OHCs in China. To derive the causal effect of the city-levels (two levels inducing 1 and 0) on the Gini coefficient, we matched the focus cases in cities with rich healthcare resources with the potential control cities. For each of the specialty categories, we first estimated the average treatment effect of the specialty category's Gini coefficient (SCGini) with the balanced covariates. For the Gini coefficient of online views, the average treatment effect of level-1 cities is 0.573, which is 0.016 higher than that of the matched group. Similarly, for the Gini coefficient of serviced patients, the average treatment effect of level-1 cities is 0.470, which is 0.029 higher than that of the matched group. The results support the argument that the total Gini coefficient of the doctors in OHCs shows that the inequality in health services is still very serious. This study contributes to the development of a theoretically grounded understanding of the causal effect of city-level factors on the inequality of health services in an online to offline health service setting. In the future, heterogeneous results should be considered for distinct groups of doctors who provide different combinations of online contributions and online attendance.

In situ chemically crosslinked injectable hydrogels for the subcutaneous delivery of trastuzumab to treat breast cancer.

Recently, novel approaches for the delivery of therapeutic antibodies have attracted much attention, especially sustained release formulations. However, sustained release formulations capable of carrying a high antibody load remain a challenge for practical use. In this study, a novel injectable hydrogel composed of maleimide-modified γ-polyglutamic acid (γ-PGA-MA) and thiol end-functionalized 4-arm poly(ethylene glycol) (4-arm PEG-SH) was developed for the subcutaneous delivery of trastuzumab. γ-PGA-MA and 4-arm PEG-SH formed a hydrogel through thiol-maleimide reactions, which had shear-thinning properties and reversible rheological behaviors. Moreover, a high content of trastuzumab (>100 mg/mL) could be loaded into this hydrogel, and trastuzumab demonstrated a sustained release over several weeks through electrostatic attraction. In addition, trastuzumab released from the hydrogel had adequate stability in terms of its structural integrity, binding bioactivity, and antiproliferative effect on BT-474 cells. Pharmacokinetic studies demonstrated that trastuzumab-loaded hydrogel (Her-hydrogel-10, composed of 1.5% γ-PGA-MA, 1.5% 4-arm PEG-SH, and 10 mg/mL trastuzumab) and trastuzumab/Zn-loaded hydrogel (Her/Zn-hydrogel-10, composed of 1.5% γ-PGA-MA, 1.5% 4-arm PEG-SH, 5 mM ZnCl2, and 10 mg/mL trastuzumab) could lower the maximum plasma concentration (Cmax) than the trastuzumab solution. Furthermore, Her/Zn-hydrogel-10 was better able to release trastuzumab in a controlled manner, which was ascribed to electrostatic attraction and formation of trastuzumab/Zn nanocomplexes. In a BT-474 xenograft tumor model, Her-hydrogel-10 had a similar tumor growth-inhibitory effect as that of the trastuzumab solution. By contrast, Her/Zn-hydrogel-10 exhibited a superior tumor growth-inhibitory capability due to the functionality of Zn. This study demonstrated that this hydrogel has potential as a carrier for the local and systemic delivery of proteins and antibodies. STATEMENT OF SIGNIFICANCE: Recently, novel sustained-release formulations of therapeutic antibodies have attracted much attention. However, these formulations should be able to carry a high antibody load owing to the required high dose, and these formulations remain a challenge for practical use. In this study, a novel injectable chemically cross-linked hydrogel was developed for the subcutaneous delivery of trastuzumab. This novel hydrogel possessed ideal characteristics of loading high content of trastuzumab (>100 mg/mL), sustained release of trastuzumab over several weeks, and maintaining adequate stability of trastuzumab. In vivo studies demonstrated that a trastuzumab-loaded hydrogel possessed the ability of controlled release of trastuzumab and maintained antitumor efficacy same as that of trastuzumab. These results implied that a γ-PGA-MA and 4-arm PEG-SH-based hydrogel has great potential in serving as a carrier for the local or systemic delivery of therapeutic proteins or antibodies.

Oral Nonviral Gene Delivery for Chronic Protein Replacement Therapy.

Efficient nonviral oral gene delivery offers an attractive modality for chronic protein replacement therapy. Herein, the oral delivery of insulin gene is reported by a nonviral vector comprising a copolymer with a high degree of substitution of branched polyethylenimine on chitosan (CS-g-bPEI). Protecting the plasmid from gastric acidic degradation and facilitating transport across the gut epithelium, the CS-g-bPEI/insulin plasmid DNA nanoparticles (NPs) can achieve systemic transgene expression for days. A single dose of orally administered NPs (600 µg plasmid insulin (pINS)) to diabetic mice can protect the animals from hyperglycemia for more than 10 d. Three repeated administrations spaced over a 10 d interval produce similar glucose-lowering results with no hepatotoxicity detected. Positron-emission-tomography and computed-tomography images also confirm the glucose utilization by muscle cells. While this work suggests the feasibility of basal therapy for diabetes mellitus, its significance lies in the demonstration of a nonviral oral gene delivery system that can impact chronic protein replacement therapy and DNA vaccination.

Aglycone geniposidic acid, a naturally occurring crosslinking agent, and its application for the fixation of collagenous tissues.

A natural compound, aglycone geniposidic acid (aGSA), originated from the fruits of Gardenia jasminoides ELLIS was used for the fixation of collagenous tissues. The presumed crosslinking reaction mechanism of collagenous tissues with aGSA was inferred by reacting aGSA with a bifunctional amine, 1,6-hexanediamine, using a series of (1)H NMR, FT-IR, and UV/Vis spectra analyses. aGSA reacted with 1,6-hexanediamine by a nucleophilic attack on the olefinic carbon atom at C-2 of deoxyloganin aglycone, followed by opening the dihydropyran ring to form heterocyclic amine compounds. It is inferred that aGSA may form intramolecular and intermolecular crosslinks with a heterocyclic structure within collagen fibers in tissues. The degrees of tissue fixation by aGSA at different pH values were investigated by examining the fixation indices and denaturation temperatures of test samples. It was found that the fixation indices and denaturation temperatures of test samples fixed at neutral or basic pH (pH 7.4 or pH 8.5) were significantly greater than at acidic pH (pH 4.0). The results obtained in this study may be used to elucidate the crosslinking mechanism and optimize the fixation process for developing bioprostheses fixed by aGSA.

Paclitaxel-loaded poly(gamma-glutamic acid)-poly(lactide) nanoparticles as a targeted drug delivery system for the treatment of liver cancer.

The study was to develop paclitaxel-loaded formulations using a novel type of self-assembled nanoparticles (P/NPs) composed of block copolymers synthesized by poly(gamma-glutamic acid) and poly(lactide). For the potential of targeting liver cancer cells, galactosamine was conjugated on the prepared nanoparticles (Gal-P/NPs). In the in vitro studies, it was found that both the P/NPs and the Gal-P/NPs had a similar release profile of paclitaxel. The activity in inhibiting the growth of HepG2 cells by the Gal-P/NPs was comparable to that of a clinically available paclitaxel formulation (Phyxol), while the P/NPs displayed a significantly less activity (p<0.05). The biodistribution and anti-tumor efficacy of the prepared nanoparticles were studied in hepatoma-tumor-bearing nude mice. It was found that the groups injected with Phyxol, the P/NPs or the Gal-P/NPs significantly delayed the tumor growth as compared to the control group injected with PBS (p<0.05). Among all studied groups, the group injected with the Gal-P/NPs appeared to have the most significant efficacy in the reduction of the size of the tumor. This is because a large number of the Gal-P/NPs were observed at the tumor site, and subsequently released their encapsulated paclitaxel to inhibit the growth of the tumor. The aforementioned results indicated that the Gal-P/NPs prepared in the study had a specific interaction with the hepatoma tumor induced in nude mice via ligand-receptor recognition. Therefore, the prepared Gal-P/NPs may be used as a potential drug delivery system for the targeted delivery to liver cancers.

Physicochemical, antimicrobial, and cytotoxic characteristics of a chitosan film cross-linked by a naturally occurring cross-linking agent, aglycone geniposidic acid.

The purpose of this study was to evaluate the characteristics of a chitosan film cross-linked by a naturally occurring compound, aglycone geniposidic acid (aGSA). This newly developed aGSA-cross-linked chitosan film may be used as an edible film. The chitosan film without cross-linking (fresh) and the glutaraldehyde-cross-linked chitosan film were used as controls. The characteristics of test chitosan films evaluated were their degree of cross-linking, swelling ratio, mechanical properties, water vapor permeability, antimicrobial capability, cytotoxicity, and enzymatic degradability. It was found that cross-linking of chitosan films by aGSA (at a concentration up to 0.8 mM) significantly increased its ultimate tensile strength but reduced its strain at fracture and swelling ratio. There was no significant difference in the antimicrobial capability between the cross-linked chitosan films and their fresh counterpart. However, the aGSA-cross-linked chitosan film had a lower cytotoxicity, a slower degradation rate, and a relatively lower water vapor permeability as compared to the glutaraldehyde-cross-linked film. These results suggested that the aGSA-cross-linked chitosan film may be a promising material as an edible film.

A novel drug-eluting stent spray-coated with multi-layers of collagen and sirolimus.

In the study, a novel drug-eluting stent for treating the coronary arterial stenosis was developed. Using a spray-coating method, aqueous bovine type I collagen and sirolimus were coated layer-by-layer alternatively onto the surface of a metallic stent and a topcoat of collagen was used as a barrier to control drug release. To prevent dissolution of the collagen matrices, the spray-coated collagen was further crosslinked by genipin, a naturally occurring crosslinking agent. The results obtained in the atomic force microscopy (AFM) examination suggested that the spray-coated collagen was tightly adhered to the surface of the stent. Additionally, the collagen coating was demonstrated by the scanning electron microscopy (SEM) to be sufficiently flexible to allow balloon expansion of the stent without cracking or peeling from the wire. The resistance against enzymatic degradation and the hemocompatibility of the collagen matrices increased significantly as their degree of crosslinking increased. All the studied sirolimus-loaded stents exhibited a nearly linear sustained-release profile (except at the end stage of release) with no significant burst releases. It was found that a topcoat of collagen on the collagen/sirolimus coated stent did slow down the release of sirolimus to some extent. Additionally, the number of layers of collagen/sirolimus coated significantly affected the duration of sirolimus released. Furthermore, the sustained-release duration of sirolimus was proportional to the actual amount of drug loaded on the stent. The aforementioned results indicated that the drug-eluting stent developed had a tightly adhered collagen coating and can be used as a drug reservoir to sustain release of sirolimus.

Photothermal tumor ablation in mice with repeated therapy sessions using NIR-absorbing micellar hydrogels formed in situ.

Repeated cancer treatments are common, owing to the aggressive and resistant nature of tumors. This work presents a chitosan (CS) derivative that contains self-doped polyaniline (PANI) side chains, capable of self-assembling to form micelles and then transforming into hydrogels driven by a local change in pH. Analysis results of small-angle X-ray scattering indicate that the sol-gel transition of this CS derivative may provide the mechanical integrity to maintain its spatial stability in the microenvironment of solid tumors. The micelles formed in the CS hydrogel function as nanoscaled heating sources upon exposure to near-infrared light, thereby enabling the selective killing of cancer cells in a light-treated area. Additionally, photothermal efficacy of the micellar hydrogel is evaluated using a tumor-bearing mouse model; hollow gold nanospheres (HGNs) are used for comparison. Given the ability of the micellar hydrogel to provide spatial stability within a solid tumor, which prevents its leakage from the injection site, the therapeutic efficacy of this hydrogel, as a photothermal therapeutic agent for repeated treatments, exceeds that of nanosized HGNs. Results of this study demonstrate that this in situ-formed micellar hydrogel is a highly promising modality for repeated cancer treatments, providing a clinically viable, minimally invasive phototherapeutic option for therapeutic treatment.