Use of biosilica to improve loading and delivery of bone morphogenic protein 2.

The clinical utility of bone morphogenetic protein 2 (BMP2) is limited because of the poor attraction between BMP2 and carriers, resulting in low loading efficiency and initial burst release. Here, the high binding affinity of BMP2 to the biosilica surface was utilized to overcome this limitation. Atomic force microscopy revealed that BMP2 bound nearly 8- and 2-fold more strongly to biosilica-coated hydroxyapatite than to uncoated and plain silica-coated hydroxyapatite, respectively. To achieve controlled release, collagen was introduced between the silica layers on hydroxyapatite, which was optimized by adjusting the collagen concentration and number of layers. The optimal biosilica/collagen formulation induced sustained BMP2 release without compromising loading efficiency. BMP2 combined with the mentioned formulation led to an increase in osteogenesis, as compared to the combination of BMP2 with either biosilica-coated or non-coated hydroxyapatite in vitro. In rat calvarial defect models, the biosilica/collagen-coated hydroxyapatite with 1 µg BMP2 showed 26 % more bone regeneration than the same dose of BMP2-loaded hydroxyapatite and 10.6 % more than hydroxyapatite with 2.5-fold dose of BMP2. Using BMP2 affinity carriers coated with biosilica/collagen allows for more efficacious in situ loading and delivery of BMP2, making them suitable for the clinical application of growth factors through a soaking method.

Capacitive Electrode-Based Electric Field Treatments on Redox-Toxic Iron Deposits in Transgenic AD Mouse Models: The Electroceutical Targeting of Alzheimer's Disease Feasibility Study.

Iron accumulation in the brain accelerates Alzheimer's disease progression. To cure iron toxicity, we assessed the therapeutic effects of noncontact transcranial electric field stimulation to the brain on toxic iron deposits in either the Aß fibril structure or the Aß plaque in a mouse model of Alzheimer's disease (AD) as a pilot study. A capacitive electrode-based alternating electric field (AEF) was applied to a suspension of magnetite (Fe3O4) to measure field-sensitized reactive oxygen species (ROS) generation. The increase in ROS generation compared to the untreated control was both exposure-time and AEF-frequency dependent. The frequency-specific exposure of AEF to 0.7-1.4 V/cm on a magnetite-bound Aß-fibril or a transgenic Alzheimer's disease (AD) mouse model revealed the degradation of the Aß fibril or the removal of the Aß-plaque burden and ferrous magnetite compared to the untreated control. The results of the behavioral tests show an improvement in impaired cognitive function following AEF treatment on the AD mouse model. Tissue clearing and 3D-imaging analysis revealed no induced damage to the neuronal structures of normal brain tissue following AEF treatment. In conclusion, our results suggest that the effective degradation of magnetite-bound amyloid fibrils or plaques in the AD brain by the electro-Fenton effect from electric field-sensitized magnetite offers a potential electroceutical treatment option for AD.

The Potential Neuroprotective Effects of Extracts from Oat Seedlings against Alzheimer's Disease.

The physiological or dietary advantages of germinated grains have been the subject of numerous discussions over the past decade. Around 23 million tons of oats are consumed globally, making up a sizeable portion of the global grain market. Oat seedlings contain more protein, beta-glucan, free amino acids, and phenolic compounds than seeds. The progressive neurodegenerative disorder of Alzheimer's is accompanied by worsening memory and cognitive function. A key indicator of this disorder is the unusual buildup of amyloid-beta protein (or Aß) in human brains. In this context, oat seedling extract (OSE) has been identified as a new therapeutic candidate for AD, due to its antioxidant activity and AD-specific mechanism of action. This study directly investigated how OSE affected AD and its impacts by examining the cognitive function and exploring the inflammatory response mechanism. The dried oat seedlings were grounded finely with a grinder, inserted with 50% fermented ethanol 10 times (w/v), and extracted by stirring for 10 h at 45 °C. After filtering the extract by 0.22 um filter, some of it was used for UHPLC analysis. The results indicated that the treatment with OSE protects against Aß25-35-induced cytotoxicity in BV2 cells. Tg-5Xfad AD mice had strong deposition of Aß throughout their brains, while WT mice did not exhibit any such deposition within their brains. A drastic reduction was observed in terms of numbers, as well as the size, of Aß plaques within Tg-5Xfad AD mice exposed to OSE. This study indicated OSE's neuroprotective impacts against neurodegeneration, synaptic dysfunction, and neuroinflammation induced by amyloid-beta. Our results suggest that OSE acts as a neuroprotective agent to combat AD-specific apoptotic cell death, neuroinflammation, amyloid-beta accumulation, as well as synaptic dysfunction in AD mice's brains. Furthermore, the study indicated that OSE treatment affects JNK/ERK/p38 MAPK signaling, with considerable inhibition in p-JNK, p-p38, and p-ERK levels seen in the brain of OSE-treated Tg-5Xfad AD mice.

Development of an Auxiliary Device for Patellar and Femoral Joint Tangential Axial Radiographic Imaging and a Method for Obtaining an Optimal Radiographic Image Using the Development.

This study evaluated the accuracy of tangential axial radiography of the patellar and femoral joint using an auxiliary device based on three image evaluation criteria, which we named the patellofemoral joint radiography auxiliary device (PJR). To compare the PJR method with conventional radiographic methods, such as Laurin, Merchant, and Settegast, a whole-body phantom (PBU-31) was used and three image evaluation items were set. The radiographic method, the smallest inclination of the patellar and showed the best half lateral image of the patella, is Settegast, and the measurement is 9.40. The second-best PJR measurement is 9.97, and the difference between the two measures is 5.76% (p = 0.001). The radiographic method showing the image with the largest distance between the patellar and femoral joint space is PJR which a measurement is 12.35. The second best Merchant measure is 10.55, and the difference between the two measures is 14.54% (p = 0.001). The method in which the two bones were well overlapped (i.e., evaluate the distortion of the image by measured as the distance between the femoral trochlear groove and the tibial tuberosity) is the PJR and the measurement is -0.37. The second-best Merchant measure is 3.93, and the difference between the two measures is 91.4% (p = 0.001). The Settegast has the image with the smallest inclination of the patella, but the PJR has the image that best describes the patellar-femoral joint and the least distortion of the image. As a result of the comprehensive evaluation, when using PJR, bending the knee by 40° and setting a 140° angle between the long axis of the femur and the long axis of the lower leg were considered to be the most beneficial conditions. Therefore, we propose the use of PJR for tangential axial radiography of the patellar-femoral joint.

Tumor-treating fields in combination with sorafenib restrain the proliferation of liver cancer in vitro.

Liver cancer is a common malignancy worldwide, with a poor prognosis and a high recurrence rate despite the available treatment methodologies. Tumor-treating fields (TTFields) have shown good preclinical and clinical results for improving the prognosis of patients with glioblastoma and malignant pleural mesothelioma. However, there is minimal evidence for the effect of TTFields on other cancer types. Thus, the present study aimed to investigate the therapeutic efficacy of TTFields in an in vitro model, and to further elucidate the underlying mechanisms. In the present study, two hepatocellular carcinoma (HCC) cell lines (Hep3B and HepG2) were treated with TTFields (intensity, 1.0 V/cm; frequency, 150 kHz) in order to determine the potential antitumor effects of this approach. TTFields significantly inhibited the proliferation and viability of HCC cell lines, as measured using Trypan blue and MTT assays, as well as colony formation in three-dimensional cultures. The TTFields also significantly inhibited the migration and invasion of HCC cells in Transwell chamber and wound-healing assays. Moreover, TTFields enhanced the production of reactive oxygen species in the cells and increased the proportion of apoptotic cells, as evidenced by increased caspase-3 activity, as well as PARP cleavage in western blotting experiments. All of these effects were increased following the application of TTFields in combination with the multi-kinase inhibitor sorafenib, which demonstrated a synergistic effect. Thus, to the best of our knowledge, these results demonstrate for the first time the potential of TTFields in improving the sensitivity of HCC cells to sorafenib, which may lay the foundation for future clinical trials for this combination treatment strategy.

Enhanced proton treatment with a LDLR-ligand peptide-conjugated gold nanoparticles targeting the tumor microenvironment in an infiltrative brain tumor model.

The tumor microenvironment (TME) of glioblastoma malforms (GBMs) contains tumor invasiveness factors, microvascular proliferation, migratory cancer stem cells and infiltrative tumor cells, which leads to tumor recurrence in the absence of effective drug delivery in a Blood Brain Barrier (BBB)-intact TME and radiological invisibility. Low-density lipoprotein receptor (LDLR) is abundant in the blood brain barrier and overexpressed in malignant glioma cells. This study aimed to treat the TME with transmitted proton sensitization of LDLR ligand-functionalized gold nanoparticles (ApoB@AuNPs) in an infiltrative F98 glioma rat model. BBB-crossing ApoB@AuNPs were selectively taken up in microvascular endothelial cells proliferation and pericyte invasion, which are therapeutic targets in the glioma TME. Proton sensitization treated the TME and bulk tumor volume with enhanced therapeutic efficacy by 67-75% compared to that with protons alone. Immunohistochemistry demonstrated efficient treatment of endothelial cell proliferation and migratory tumor cells of invasive microvessels in the TME with saving normal tissues. Taken together, these data indicate that the use of LDLR ligand-functionalized gold nanoparticles is a promising strategy to treat infiltrative malignant glioma while overcoming BBB crossing.

Tumor-treating fields as a proton beam-sensitizer for glioblastoma therapy.

Few advances in GBM treatment have been made since the initiation of the Stupp trials in 2005. Experimental studies on immunotherapy drugs, molecular inhibitors, radiation dosage escalation and vascular growth factor blockers have all failed to provide satisfactory outcomes. TTFields therapy, on the other hand, have emerged as a viable substitute to therapies like radiation in GBM patients having a highly immunosuppressive tumor microenvironment. To enhance the biofunctional impacts, we explored the combination events with TTFields and proton treatment in this study. We conducted a cell viability test, a cell death detection evaluation, a ROS analysis, a three-dimensional (3D) culture system, and a migration assay. The combination of proton radiation and TTFields therapy laid a substantial anticancer impact on the F98 and U373 as compared to the consequences of either of these therapies used separately. The combination proton beam therapy used by TTFields was very successful in curbing GBM from migrating. GBM cell metastasis is restricted by TTFields combined proton by downregulating the MAPK, NF-κB, and PI3K/AKT indicating pathways, caused by reduced EMT marker expression. These findings furnish biological proof for the molecular grounds of TTFields in combination with proton used for GBM therapy.

Proton Stimulation Targeting Plaque Magnetite Reduces Amyloid-ß Plaque and Iron Redox Toxicity and Improves Memory in an Alzheimer's Disease Mouse Model.

BACKGROUND: The coexistence of magnetite within protein aggregates in the brain is a typical pathologic feature of Alzheimer's disease (AD), and the formation of amyloid-ß (Aß) plaques induces critical impairment of cognitive function. OBJECTIVE: This study aimed to investigate the therapeutic effect of proton stimulation (PS) targeting plaque magnetite in the transgenic AD mouse brain. METHODS: A proton transmission beam was applied to the whole mouse brain at a single entrance dose of 2 or 4 Gy to test the effect of disruption of magnetite-containing Aß plaques by electron emission from magnetite. The reduction in Aß plaque burden and the cognitive function of the PS-treated mouse group were assayed by histochemical analysis and memory tests, respectively. Aß-magnetite and Aß fibrils were treated with PS to investigate the breakdown of the amyloid protein matrix. RESULTS: Single PS induced a 48-87%reduction in both the amyloid plaque burden and ferrous-containing magnetite level in the early-onset AD mouse brain while saving normal tissue. The overall Aß plaque burden (68-82%) and (94-97%) hippocampal magnetite levels were reduced in late onset AD mice that showed improvements in cognitive function after PS compared with untreated AD mice (p < 0.001). Analysis of amyloid fibrils after exposure to a single 2 or 4 Gy proton transmission beam demonstrated that the protein matrix was broken down only in magnetite-associated Aß fibrils. CONCLUSION: Single PS targeting plaque magnetite effectively decreases the amyloid plaque burden and the ferrous-containing magnetite level, and this effect is useful for memory recovery.

Tumor treating fields can effectively overcome trastuzumab resistant breast cancer multiplication.

The Human Epidermal Growth Receptor 2, or the HER2 is one of the highest expressed negative receptor that constitutes approximately 15-20% of malevolent breast cancerous tumors among women. The prevalence of HER2 has untimely and unfavorable consequences on breast cancer, and its underlying carcinomous cell processes, structures, and growth. Trastuzumab (TRZ), a humanized antibody that is rooted in relatively recent foundations, has been found operational in its construction of treatments against HER2-positive breast cancer. This drug is combined with radiotherapy or chemotherapy to deregulate HER2 genes in the body. However, patients who suffer from evolved tumors in advanced stages of cancer exhibit a good amount of tolerance towards singularly used TRZ treatment. Inversely, the factorization of Tumor Testing Fields (TTFields or TTFs) into cancer therapy revives the functions of a TRZ treatment plan, by sensitizing the HER2 genes to the drug. In turn, this facilitates TRZ to continue limiting cancerous cell multiplication and toxicity levels within the treatment. This research evaluates the aspects and effects of this pairing, both in vivo and in vitro through BT474 cells. The TTFields conduct an electromagnetic boundary, which generates sine-wave radiations to manipulate the HER2 gene structure. The methods followed in the research also examines the gene cell cultures and their viability through solutions like Tryptophan blue, or the Crystal violet which may or may not deliver certain testmants to the experiment. The Western Blot Test and the IHC confirm the presence of antibodies and negative receptors in the BT474 cells. These procedures contribute to the formulation of a treatment plan that overcomes the TRZ-resistant nature of the tumor, which is essentially the aim of the research. Thus, the paper substantiates that a healthy combination of TTF's with TRZ can enhance the penetration of TRZ after inducing apoptosis due to TTFields therapy. The success of a TTField in undertaking this pursuit makes room for more utilization of it in future cancerous treatment ventures.

X-ray dark-field phase-contrast imaging: Origins of the concept to practical implementation and applications.

The basic idea of X-ray dark-field imaging (XDFI), first presented in 2000, was based on the concepts used in an X-ray interferometer. In this article, we review 20 years of developments in our theoretical understanding, scientific instrumentation, and experimental demonstration of XDFI and its applications to medical imaging. We first describe the concepts underlying XDFI that are responsible for imparting phase contrast information in projection X-ray images. We then review the algorithms that can convert these projection phase images into three-dimensional tomographic slices. Various implementations of computed tomography reconstructions algorithms for XDFI data are discussed. The next four sections describe and illustrate potential applications of XDFI in pathology, musculoskeletal imaging, oncologic imaging, and neuroimaging. The sample applications that are presented illustrate potential use scenarios for XDFI in histopathology and other clinical applications. Finally, the last section presents future perspectives and potential technical developments that can make XDFI an even more powerful tool.

Stimulus-Responsive Contact Lens for IOP Measurement or Temperature-Triggered Drug Release.

Purpose: Continuous monitoring of elevated intraocular pressure and timely drug delivery for successful treatment of glaucoma are necessary to reduce intraocular pressure (IOP), which shows wide variations across the circadian pattern and in response to medication. This in vivo study presents a new contact lens-based method of optical IOP measurement or temperature-triggered drug elution. Methods: A contact lens with moiré patterns of concentric circles measures the changes in eyeball diameter of a rabbit glaucoma model due to changes in IOP by superimposing a camera-captured image onto the micro pattern of the contact lens with a computer-assisted virtual reference image. Drug elution from the nanoporous bicontinuous microemulsion contact lens (BME-CL) into the eye of the rabbit was triggered by a temperature-responsive nanogel drug carrier. Results: The moiré pattern change on the contact lens was proportional to the IOP increase in the rabbit eye either ex vivo or in vivo and was also correlated with imaging-based alterations in the anterior chamber angle at a range of IOP values (3-40 mm Hg). The cumulative drug absorbed reached as high as 10.6 µg/mL aqueous humor until 7 days after wearing the BME-CL, and a 33% decrease in IOP was observed at 3 hours after drug elution. Conclusions: The results suggest that continuous measurement and treatment of elevated IOP are feasible using moiré pattern-inscribed and thermosensitive drug-eluting contact lenses, respectively. Translational Relevance: Pressure-sensing or thermosensitive contact lenses enable monitoring IOP or drug release triggered by body temperature for the treatment of glaucoma patients.

Medulla loss of scalp hair in breast cancer patients determined by near-infrared microscopy.

Inexpensive near-infrared microscopy (NIRM) was developed as a convenient technique to detect the medulla loss of scalp hair while reducing analytical time with easy sample preparation, leading to a field screening tool for breast cancer. NIRM has been evaluated as an alternative to synchrotron-based nanoscopy and to the relatively expensive method of conventional infrared microscopy to determine the degree and pattern of medulla loss of scalp hairs of patients with breast cancer and benign diseases, as well as normal healthy individuals. NIR imaging showed a strong, scattering-based hyperintense contrast of the medulla compared to the fully attenuated cortex in medullated healthy hair. Complete medulla loss (CML) per hair strand was more extensively (60.9 ± 10.2 %) (p < 0.001) detected in the hair of all cancer patients than in the hair of either healthy individuals (less than 3.7 ± 7.5%) or those with benign disease (30.6 ± 5.9 % ), suggesting a potential biomarker for breast cancer diagnosis. The medulla structure was retained mostly in the hair of age-matched healthy individuals, but discontinuous medulla loss was observed concomitantly with less CML in fibroadenoma patients. Potentially, compact NIRM modules can be integrated into a mobile platform as point-of-care technology for breast cancer screening.

Direct immobilization and recovery of recombinant proteins from cell lysates by using EctP1-peptide as a short fusion tag for silica and titania supports.

Immobilization of protein, compared to the use of free protein, offers improved stability, easy separation and continuous reusability. However, the classic routes for protein immobilization, based on non-specific adsorption, often negatively affect protein functionality. In this study, EctP1 peptide was explored as a novel short fusion tag for non-covalent adsorption on unmodified solid surfaces, silica and titania. A fusion of EctP1 with bovine carbonic anhydrase (BCA) was employed to investigate the optimal binding conditions that could diminish the nonspecific adsorption of Escherichia coli proteins. The stable binding of BCA-EctP1 on titania was observed in the pH range of 2-9, while the stable binding on silica was in the pH range 6-9. Moreover, the immobilized BCA-EctP1 on silica and titania particles showed enhanced thermal and storage stability and retained 95% of its residual activity after 5 uses. We further demonstrated the merits of the noncovalent immobilization of EctP1 fusion proteins to silica and titania in the recovery of the bound proteins. Interestingly, monomeric arginine showed better recovery yield of EctP1 fusion proteins (about 78-84%), compared to the recovery yield by the salts, NaCl and MgCl2 (about 30-51%). Using BCA and monomeric red fluorescent protein (mRFP) as model proteins, the EctP1 fusion proteins were released in a biologically active form with approximately 80% recovery and 93% purity. Our approach is a simple and reproducible technique for direct immobilization of recombinant proteins from E. coli lysates on solid supports, with the potential high-purity recovery of recombinant proteins.

Anti-Flt1 peptide and cyanine-conjugated gold nanoparticles for the concurrent antiangiogenic and endothelial cell proton treatment.

Anti-Flt1 peptide of GNQWFI binds to vascular endothelial growth factor receptor 1 (VEGFR1 or Flt1) and prevents binding of VEGF, inhibiting VEGFR1-mediated endothelial cell migration and tube formation. Bare gold nanoparticle (AuNP) was known to have anti-angiogenic properties by specific binding with VEGF. In this study, anti-Flt1 peptide (GGNQWFI) and cyanine were chemically conjugated to AuNPs (Flt1@AuNP-cyanine 5.5 or Flt1@AuNP-hydrocyanine 5.5 [HCy5.5]) to enhance antiangiogenic properties with targeting to VEGFR-1 as well as producing Coulomb nanoradiator therapeutic effect on the retinal endothelial cells. Anti-Flt1 AuNP complex showed binding with VEGFR-1 and showed more protein-induced fluorescence enhancement (PIFE) by various VEGFs compared with bare AuNPs, suggesting enhanced antiangiogenic properties compared to bare AuNP. Nonfluorescent Flt1@AuNP-HCy5.5 successfully reacted with reactive oxygen species (ROS) produced from Fenton reactions or a proton-induced Coulomb nanoradiator, enabling quenching-free oxidant fluorescence ROS imaging in HRMECs under oxidative stress. Flt1@AuNP-HCy5.5 alone induced 50% greater cytotoxicity for HRMECs compared to bare AuNPs and 80% greater cell death by the Au-nanoradiator effect. In conclusion, this study describes a new therapeutic anti-Flt1 gold nanocomplex with enhanced antiangiogenic properties and nanoradiator-mediated cytotoxicity on retinal endothelial cells. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1272-1283, 2019.

Thermo-sensitive nanogel-laden bicontinuous microemulsion drug-eluting contact lenses.

The bicontinuous microemulsion contact lens (BMCL) has nanoporous biphasic structures (100-250 nm) that are interconnected via multiple nano-channels, providing suitable retention of various drugs for glaucoma. Timolol maleate (TM)-carried thermosensitive poly(N-isopropylacrylamide) (PNIPAM) nanogel (30-50 nm) was incorporated into BMCLs by soaking or by centrifuging plus soaking. Here, we present drug-loading and release in silicon- or polyethylene oxide-microemulsion BMCLs under various conditions. Nanoporous BMCLs containing thermosensitive TM-laden nanogel were capable of potent body-temperature-triggered release of TM. Daily drug release was controllable according to the initial volume of drug-loaded (VDL) and loading method for sustained drug release, making them reduce drug-loss during transportation or storage. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1159-1169, 2019.

Track analysis of a synchrotron X-ray photoelectric nanoradiator by in situ fluorescence imaging of reactive oxygen species: comparative study of gold and iron oxide nanoparticles.

The emission of fluorescent X-rays and low-energy electrons by mid-/high-Z nanoparticles upon irradiation with either X-ray photons or high-energy ion beams is referred to as the nanoradiator effect (NRE). A track analysis of NRE was performed using reactive oxygen species (ROS) gels, to which macrophages containing gold nanoparticles (AuNPs) were attached, together with single-cell irradiation of the intracellular nanoparticles from a microbeam of synchrotron X-rays, and the range and distribution of ^\bulletOH and O2^{ \bullet - } produced were compared with those of the Fe-nanoradiator by magnetite nanoparticles (FeONP, Fe3O4). The Au-nanoradiator generated ROS fluorescence to a greater depth and wider angle with respect to the incident X-rays than that of the Fe-nanoradiator. The ROS-oxidant fluorescence intensity ratios of ^\bulletOH to O2^{ \bullet - } were different for the AuNPs and FeONPs, reflecting different relative yields of electrons and fluorescent X-rays from NRE. In the region immediately (<100 µm) below the irradiated cell, ^\bulletOH-radicals were distributed mainly along two or three tracks in the depth direction in the FeONP- or AuNP-ROS gel. In contrast, O2^{ \bullet - } was scattered more abundantly in random directions in the AuNP-ROS gel than in the FeONP-ROS gel. Track analysis of X-ray photoelectric nanoradiator radiation showed a different range of dose distribution and relative emission compositions between Au- and Fe-nanoradiators, suggesting more extensive damage beyond a single cell containing AuNPs than one containing FeONPs.

Intravitreal implantable magnetic micropump for on-demand VEGFR-targeted drug delivery.

In this paper, we propose an intravitreal implantable magnetic micropump integrated with micro check valve capable of on-demand vascular endothelial growth factor receptor (VEGFR)-targeted drug delivery for the treatment of age-related macular degeneration, diabetic retinopathy and other eye pathologies characterized by ocular neoangiogenesis. Precise on-demand drug release is realized by the deflection of the magnetic membrane assembly according to the external magnetic field, and the membrane assembly consists of a thin elastic polydimethylsiloxane (PDMS) membrane and a cylindrical magnetic nanoparticle-PDMS composite block. Additionally, a micro check valve composed of two PDMS layers was integrated into the micropump to realize a diode-like one-directional drug delivery and prevent undesired drug diffusion. For specifically targeting VEGFR and suppression of VEGF-induced proliferation of microvascular endothelial cells, anti-Flt1 gold nanocomplexes are synthesized. In vitro and in vivo experiments and quantitative analysis are carried out in order to verify our proposed concept: precise drug release control according to the external magnetic field, targeting to microvascular endothelial cells, and efficient and on-demand drug delivery from the proposed micropump to the macular area of rabbit's eye.

Enhanced production of reactive oxygen species in HeLa cells under concurrent low­dose carboplatin and Photofrin® photodynamic therapy.

Concurrent low­dose carboplatin/Photofrin® photodynamic therapy (ccPDT) has been shown to promote relapse­free complete tumor regression in cervical or endometrial cancer patients as a fertility­preservation therapy. This study aimed to investigate the molecular mechanism of the enhanced therapeutic efficacy of ccPDT by determining intracellular reactive oxygen species (ROS) and necrotic or apoptotic cell damage in HeLa cells loaded with fluorescent oxidant agents and Photofrin or/and carboplatin under light irradiation. The cytotoxic effects of ccPDT were compared when monitored with a light dose under carboplatin or Photofrin alone. Photofrin­PDT alone did not enhance either hydroxyl radicals (OH•) or superoxide anions (O2•-), but a slight enhancement of hydrogen peroxide (H2O2) production was observed. A larger enhancement of ROS production was obtained in a dose­dependent manner following ccPDT, especially OH• and H2O2, in conjunction with both necrotic and apoptotic cell death, compared with necrotic­prone PDT alone. The carboplatin­mediated Fenton reaction: 2[PtII]2 + H2O2 → [Pt2.25]4 + OH¯+ OH• was proposed to explain the dose­dependent enhancement of OH•. In conclusion, the therapeutic enhancement of ccPDT in vitro was attributable to the carboplatin­mediated synergetic production of OH▪ and apoptotic cellular damage, compared with Photofrin­PDT alone.

Development of Gallic Acid-Modified Hydrogels Using Interpenetrating Chitosan Network and Evaluation of Their Antioxidant Activity.

In this work, antioxidant hydrogels were prepared by the construction of an interpenetrating chitosan network and functionalization with gallic acid. The poly(2-hydroxyethyl methacrylate) p(HEMA)-based hydrogels were first synthesized and subsequently surface-modified with an interpenetrating polymer network (IPN) structure prepared with methacrylamide chitosan via free radical polymerization. The resulting chitosan-IPN hydrogels were surface-functionalized with gallic acid through an amide coupling reaction, which afforded the antioxidant hydrogels. Notably, gallic-acid-modified hydrogels based on a longer chitosan backbone exhibited superior antioxidant activity than their counterpart with a shorter chitosan moiety; this correlated to the amount of gallic acid attached to the chitosan backbone. Moreover, the surface contact angles of the chitosan-modified hydrogels decreased, indicating that surface functionalization of the hydrogels with chitosan-IPN increased the wettability because of the presence of the hydrophilic chitosan network chain. Our study indicates that chitosan-IPN hydrogels may facilitate the development of applications in biomedical devices and ophthalmic materials.